Qos and Traffic Load b8 8as902001424vhzza3

1

© Alcatel University - 8AS 90200 1424 VT ZZA Ed.031.1

Introduction to

QUALITY OF SERVICE and TRAFFIC LOAD

MONITORING

BSS release B8

B8

1.2

PROGRAM

1 INTRODUCTION2 GLOBAL INDICATORS3 DETAILED INDICATORS4 HANDOVER INDICATORS5 DIRECTED RETRY INDICATORS6 RADIO MEASUREMENT STATISTICS INDICATORS7 TRAFFIC INDICATORS

B8

2


1 INTRODUCTION

1.4

1 IntroductionSession presentation

t Objective: to be able to explain what is QoS and Traffic Load monitoring of the BSS and what are the information sources available for that purpose

t Program: 1.1 Monitoring the QoS of the BSS 1.2 Monitoring the Traffic Load of the BSS1.3 Information sources available1.4 Introduction to K1205 PC emulation

3


1 INTRODUCTION

1.1 Monitoring the QoS of the BSS

1.6

1.1 Monitoring the QoS of the BSSDefinition

t ”Monitor" "network" "quality"èmonitor = measure or ensure? è network = BSS? BSS+NSS? BSS+NSS+PSTN …è quality = service (end-user) and/or system (technical)

t But also detect, localize, diagnose outagesè detect (decide according to thresholds)è localize (which cell, BSC, etc.)è diagnose: radio, BSS, TC problems

4

1.7

1.1 Monitoring the QoS of the BSSUsage

QoS ResultsQoS Results

Management•network monitoring•comparison with competitor•comparison of manufacturers•contractual requirement: licence•quality responsible

Management•network monitoring•comparison with competitor•comparison of manufacturers•contractual requirement: licence•quality responsible

Radio optimization•cell radio quality survey•HO quality monitoring•assessment of tuning efficiency

Radio optimization•cell radio quality survey•HO quality monitoring•assessment of tuning efficiency

BSS maintenance•cell/BSC/TC problem detection

BSS maintenance•cell/BSC/TC problem detection


1 INTRODUCTION

1.2 Monitoring the Traffic Load of the BSS

5

1.9

1.2 Monitoring the Traffic Load of the BSS Definition

t Measure the "quantity" of traffic handled by:è the networkè the BSCsè the cells

t Analyze traffic characteristicsè call, handover, location update, etc.

t As input for dimensioning/architecture team


1 INTRODUCTION

1.3 Information sources available

6

1.11

1.3 Information sources available Observation means

t DIFFERENT WAYS TO OBSERVE/MEASURE the GSM network

External Interface AnalysisA interface: MSC/TC-BSCAbis interface: BSC/BTSAir MS/BTS

Counter browser

OMC CountersBSC(NSS)

Tektronix K1205

Gnnettest MPAW&G NPA

1.12

1.3 Information sources available A interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "A"

t Capture/decode signaling between MSC and BSC-TC (A or AterMUX)with "protocol analyzer" (Wandel, Tektronix, Gnnettest, etc.)

+ GSM standard, can be used for arbitrage between manufacturers+ Complete information (message contents, time-stamp)+ Possible detection of User/MS/BSS/TC/NSS problems- High cost of equipment- Time consuming, "post mortem" (installation of tool, file analysis)- Important expertise needed for analysis- Low coverage (K1103/MA10: 8 COCs, K1205/MPA: 32 COCs maximum!) - Large amount of data (>> 10 Mbytes /hour/BSC)

7

1.13

1.3 Information sources available Example of trace

t on a K1205 protocol analyzer

1.14

1.3 Information sources available Abis interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "Abis"t Capture/decode signaling between BSC and BTS with "protocol

analyzer" (Wandel, Tektronix, Gnnettest, etc.): Complete information (message contents, time-stamp): Possible detection of User/MS/BSS/TC/NSS problems: Complete radio information thanks to measurement messages: Downlink and uplink – High cost of equipment– Time consuming, "post mortem" (installation of tool, file analysis)– Important expertise needed for analysis– Very low coverage (A few RSLs, a few cell(s))– Very large amount of data (>> 10 Mbytes/hour/BTS)

8

1.15

1.3 Information sources available Air interface trace

INFORMATION SOURCE: EXTERNAL INTERFACE "Air"

t Use trace MS to capture signaling and signal characteristics

: Give precise location (x,y) of problems: Give downlink radio information: Only way to localize a lack of coverage: Only way to monitor competitor– High cost of equipment– Very time-consuming– Difficulty to perform a lot of calls

è number of samples insufficient è only a few streets

– No uplink

1.16

1.3 Information sources available Performance Measurement counters

SUB-SYSTEM COUNTERS

t Counts events seen by sub-system, value reported periodically (1 hour)

: Low cost: collected directly at OMC: Compact data: possibility to store counters for a complete network

– Raw information, having to be consolidated to be understandable– Manufacturer's dependent: questionable/difficult to compare– Weak to analyze other sub-systems

9

1.17

1.3 Information sources available Exercise

t Training exercisel Draw the BSS PM counters flow on the chartl In which sub-system are the BSS QoS indicators computed

and stored?

BSC

BSC

BSC

OMC-R

OMC-R OMC-R

NPA

1.18

1.3 Information sources available BSS counters

BSS COUNTERS

t Combined into significant formulae: indicatorst Used to monitor BSS network qualityt Over a complete network, with breakdown per cell/BSC

t SPECIFIC DRAWBACKl NSS/PSTN/MS/USER problems not seen

10

1.19

1.3 Information sources available NSS counters

NSS COUNTERS

t Combined into significant formulas: indicatorst Used to monitor NSS network qualityt Over a complete network, with breakdown per BSC (maximum)

t SPECIFIC DRAWBACKSl BSS problems usually not precisely identifiedl No breakdown per cell

1.20

1.3 Information sources available ALCATEL BSS counters

INFORMATION SOURCES: BSS CountersIn order to provide the operators with an easy and cost-effective way to monitor their network and carried traffic, BSS manufacturers have implemented specific software features, called performance management.

The principle is to count for a given duration called granularity period (typically 1 hour) pre-defined events occurring on the Abis or A interface, or internally. These counters are stored for each duration, with breakdown per network component (i.e. cell).

In BSS B8, about 970 counters are available (without GPRS).

In Alcatel BSS (except GPRS), counters are computed by BSC, based mainly on Abis messages.Every reporting period, counters values are sent to the OMC-R for storage.In B7 159 ALCATEL counters are reported to the OMC-R permanently every PM granularity period:

è3 per cell adjacency è20 per TRXè127 per cellè4 per N7 linkè5 per BSC

⇒ millions of counters are collected every day

11

1.21

1.3 Information sources available Example of BSS counter

t MC718: counter numbert NB_TCH_NOR_ASS_SUCC_TRX: counter namet Cumulative: method of computationt Type 110: Overview measurements: BSS PM measurement type to which the counter

belongs t Measured object: minimum object level for which the counter is provided: TRX or CELL or

BSC or N7 LINK or X25 LINK etc.

Counter Example

1.22

1.3 Information sources available BSS counter characteristics

Collection mechanism

t Cumulativel The counter is incremented at the occurence of a specific eventl Abis or A message, or internal eventl At the end of a collection period, the result is the sum of the events

t Inspectionl Every 20 or 10 seconds, a task quantifies an internal resource status

(usually a table)l At the end of a collection period, the result is the mean value

t Observationl Set of recorded information about a telecom procedure (handover,

channel release, UL & DL measurements reporting)

12

1.23

BSS Performance Measurement types

1.3 Information sources available BSS PM types

N° Type Name Type definition1 Traffic Measurement Set of counters related to the traffic evaluation per telecom procedure2 Resource Availability Measurement Set of counters related to the availability of the CCCH, SDCCH, or TCH channels3 CCCH channel resource usage measurements Set of counters related to the usage of CCCH channel (PCH, AGCH, RACH)4 SDCCH channel resource usage measurements Set of counters related to the usage of SDCCH channel5 TCH channel resource usage measurements Set of counters related to the usage of TCH channel6 TCH Handover Measurements Set of counters related to the TCH handover procedure7 LAPD Measurement Set of counters related to the LapD logical links8 X.25 Measurement Set of counters related to the X25 links OMC-BSC9 N7 Measurement Set of counters related to the N7 Signaling Links

10 SDCCH Observations Observation counters on SDCCH channels allocated11 TCH measurements observations Observation counters on 08.58 MEASUREMENT REPORT for a TCH12 Internal Handover Observations Observation counters on internal intra-cell or inter-cell SDCCH or TCH handover13 Incoming External Handover Observations Observation counters on incoming external SDCCH or TCH handover14 Outgoing External Handover Observations Observation counters on outgoing external SDCCH or TCH handover15 TCH Observation Observation counters on TCH channel allocated18 A Interface measurements different causes of 08.08 CLEAR REQUEST and 08.08 ASSIGNMENT FAILURE19 SMS PP Measurements Set of counters related to Short Message Service Point to Point25 SCCP Measurements Set of counters related to SCCP Layer of the N7 signaling Links26 TCH outgoing Handover per adjency Set of counters related to outgoing TCH handover provided per adjency27 TCH incoming Handover per adjency Set of counters related to incoming TCH handover provided per adjency28 SDCCH Handover Set of counter related to the SDCCH handover procedure29 Directed Retry measurements Set of counter related to the directed retry handover procedure30 SMS CB Measurements Set of counters related to Short Message Service Cell Broadcast31 Radio Measurement Statistics Set of counters providing radio quality measurements for TRX/Cell32 Change of frequency band measurements Set of counters related to handovers including a change of TCH Frequency band

110 Overview measurements Set of key counters allowing to access Quality of Service of a given Cell/BSC/Network180 Traffic Flow measurements Set of counters related to incoming inter-cell SDCCH/TCH handover performed

per (servin a cell, target cell) adjency

B8

NewB8

1.24

1.3 Information sources available Observation means

t Training exercise: find the best source of information

Observation to be done : best source why

overall radio quality of 1 cell Counters Type 31 : RMS

monitor user failures

get average network quality

localise precise location of a radio pb

identify abnormal cells in a network

history of network quality for several weeks

compare networks quality

discriminate problems between BSS/ NSS. BSSand NSS coming from different providersmake statistics about complete network

In a building, one is thinking that an elevator isinducing PCM trouble, how to confirm ?Identify potential interfering cells of 1 cell

13


1 INTRODUCTION

1.4 Introduction to K1205 PC emulation

1.26

1.4 Introduction to K1205 PC emulation Usage

INTRODUCTION TO K1205 PC EMULATION

t The trace done with K1205 can be read: lDirectly on K1205 itselflOn any PC Windows NT with dedicated emulation software

t Practical exercises will be done during the course using this software

t The following slides and exercises are here to teach you the basic skill needed to operate the tool for A Interface decoding

14

1.27

1.4 Introduction to K1205 PC emulation Scenarios screen

To select binary trace file and

decoding protocol

To select binary trace file and

decoding protocolTo enter in

monitoring modeTo enter in

monitoring mode

1.28

1.4 Introduction to K1205 PC emulation Monitor screen

1 line / message1 line / message

Full decoding of selected messageFull decoding of

selected message

Message content in hexadecimal

Message content in hexadecimal

To extract 1 callTo extract 1 call

15

1.29

1.4 Introduction to K1205 PC emulation Filter configuration

HOW TO EXTRACT A CALL ON THE INTERFACE

1) Filter out paging messaget Keep only BSSAP and DTAPt Except PAGING

2) Use SCCP references t 1 on any messaget The 2 on CC message

ANNEX 3

1.30

1.4 Introduction to K1205 PC emulation Call extraction

Then

16

1.31

PRACTICAL EXERCICE

t Use the tool to extract a few calls from file PAIB29.REC

1.4 Introduction to K1205 PC emulation Exercise


2 GLOBAL INDICATORS

17

1.33

2 Global indicatorsSession presentation

t Objective: to be able to explain what is a Global indicator and what are the main BSS indicators regarding GSM services provided by the Alcatel BSS

t Program: 2.1 Indicators definition2.2 Methodological precautions2.3 Typical call failures2.4 Description of global indicators2.5 Traps and restrictions of global indicators2.6 Global indicators interpretation


2 GLOBAL INDICATORS

2.1 Indicators definition

18

1.35

2.1 Indicators definitionGlobal / detailed

BSS INDICATORS DEFINITION (Alcatel)

t Numerical data providing information about network performance regarding: l The complete network: GLOBAL indicatorl An element of the network: DETAILED indicatorèTS/TRX/CELL/BTS/BSC/TC

t A formulae of several counter(s)t Counters vs. Indicatorsl Counters: provided by the BSS equipmentsl Indicators: computed by BSS Monitoring equipments

1.36

2.1 Indicators definitionGlobal

GLOBAL INDICATORS

t Measure the performance of the complete network

t Analyzed according their trend and valuesl Usually every day (week, month)

t Compared with:l Competitor results if availablel Contractual requirementsl Internal quality requirements

19

1.37

2.1 Indicators definitionThresholds

EXAMPLE: Thresholds on Call Drop Rate indicator

Weekly CDR "GSM"

0,00%

0,50%

1,00%

1,50%

2,00%

2,50%

3,00%

3,50%

1 5 9 13 17 21 25 29 33 37 41 45week number

CD

R

weekly call drop ratecontractual call drop ratequality CDR

Weekly CDR "GSM"

0,00%

0,50%

1,00%

1,50%

2,00%

2,50%

3,00%

3,50%

1 5 9 13 17 21 25 29 33 37 41 45week number

CD

R

weekly call drop ratecontractual call drop ratequality CDR

1.38

2.1 Indicators definitionExercise

TRAINING EXERCISE: GLOBAL OR NOT

INDICATOR DESCRIPTION G ?average of call setup success rate for the network Yesrate of call lost due to radio pb on cell CI=14, LAC=234 Nocall drop rate in your capitalcall drop rate of the cell covering a specific buidling% of HO with the cause better cell (among other causes) for the networkaverage rate of TCHs dropped for all TRXs of the network carrying 1 SDCCH8rate of SDCCHs dropped on TRX1 of cell 12,24call success of 1 PLMN% of cells being congested today

20


2 GLOBAL INDICATORS

2.2 Methodological precautions

1.40

2.2 Methodological precautions Objective

METHODOLOGICAL PRECAUTIONS

t Avoid typical errors regarding indicators interpretation

21

1.41

A good value for a global indicator

⇓All network components are OK regarding this indicator

Examplet A global call drop rate of 1%t Can hide some cells with 10 % of call drop rate

2.2 Methodological precautions Global indicator value

1.42

2.2 Methodological precautions Network Element aggregation

t THE AVERAGE VALUE OF AN INDICATOR FOR A NETWORKl IS NOT THE AVERAGE OF CELL RESULTS (or any sub-part

of it)l BUT THE AVERAGE WEIGHTED BY THE TRAFFIC

number of calls number of call drop call drop ratecell 1 390 8 2,10%cell 2 546 29 5,25%cell 3 637 20 3,10%cell 4 1029 12 1,14%cell 5 536 3 0,50%cell 6 2 1 50,00%cell 7 3 1 33,00%cell 8 210 4 2,11%cell 9 432 5 1,20%cell 10 321 4 1,11%

average of cell results 9,95%total nb of drop/total number of calls 2,10%

22

1.43

2.2 Methodological precautions Global indicator validity

t To be reliable, an indicator must be based on a sufficient number of eventsl Estimation theory (MR.Spiegel, « theory and problems of probability and statistics »,

SCHAUM): è if « p » is the probability of success for a complete populationè if one is measuring the probability P based on a sample of size « N »

l There is a probability of 95 % that p is between P +/- 1.96*[(p*(1-p))/n] 0.5

l Example: for p = 90 % and N = 100 => [ 84,12% ; 95,88% ]

t This law cannot be used directly for indicators (an hourly indicator is not based on a random sample), but it is giving a rough estimate of level of confidence one can apply regarding the size of the samplel If a sample (number of calls) is too small, one can take it for a longer

duration

1.44

2.2 Methodological precautions Time period aggregation

t Take care of data consolidation

t Example: l Mean cell congestion rate during busy hourl Weighted average of cell congestion at the busy hour of the

network? l Weighted average of cell congestion rate for its specific

busy hour? l (definition of busy hour?)

23

1.45

2.2 Methodological precautions Exercise

METHODOLOGICAL PRECAUTION: Training exercise

INDICATOR Sample(calls)

conclusion OK ?

call drop = 0.9% in your country 2456435 all the cells have a good call drop NOK

call setup success for cell 15, 145 = 99,5% 2315 there is a good call setup success rate for15,145

In Paris : 2500 cells with 95% of call setupsuccessIn the rest of France : 5000 cells with98%

3267872for France

In France, call setup success = 97 %

call drop for BSS «BSS_1 » = 1% 4500 the call drop for BSS_1 is good

call drop for cell 156;13 = 5% 215 cell 156;13 has certainly a trouble

for BSS 1, call drop of 2,0%for BSS 2, call drop of 3,0%

40002000

LA = BSS1 + BSS2 has a call drop of 2,3 %

MSC « Stadium » has a call setup success of95 %

15346 BSS1 belonging to MSC Stadium has a call setupsuccess of 95¨%


2 GLOBAL INDICATORS

2.3 Typical call failures

24

1.47

2.3 Typical call failures Objective

t Description of the main call success and failures cases, withl Main specific countersl Main protocol timers

t Diagnose the main case of failures on A interface traces using K1205 emulation software

1.48

2.3 Typical call failures Call Setup phasing

4 stages for a call establishment, 2 for a location updatet Radio link establishmentt "SDCCH phase"

then only for "Circuit Switch call"t TCH assignment t "Alerting/connection" phase

Each phase has a specific utility and weaknesses

25

1.49

2.3 Typical call failures Radio Link Establishment - OC success

Originated Call: RLE success case

t T3101: guard timer for SDCCH allocation (Default: 3 seconds)t CR/CC are used to exchange SCCP references

l Any further message related to this call will have one (or 2) of these 2 referencesl K1205 can extract the call using these references (SLR, DLR!!)

MS BTS BSC MSC

CHANNEL REQUEST-------------(RACH)------------> CHANNEL REQUIRED

----------------------------------------------> MC8CCHANNEL ACTIVATION (SDCCH)

<---------------------------------------------- MC148CHANNEL ACTIVATION ACK

---------------------------------------------->IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- start T3101MC8B

<------------(AGCH)-------------SABM (L3 info)

-------------(SDCCH)-----------> ESTABLISH IND (L3 info)UA (L3 info) ----------------------------------------------> stop T3101

<----------- (SDCCH)------------- MC02CR (COMPLETE L3 INFO)---------------------------------->

CC<----------------------------------

B8

NewB8

Specific case of Call establishmentfailure:

Loss of messages due to LapD congestioncan be follow with a new counter (see notes)LapD

1.50

2.3 Typical call failures Radio Link Establishment - TC success

Terminated Call: RLE success caseMS BTS BSC MSC

PAGINGPAGING COMMAND <----------------------------------

PAGING REQUEST <---------------------------------------------- start T3113<-------------(PCH)-------------- MC8A


----------------------------------------------> MC8CCHANNEL ACTIVATION (SDCCH)

<---------------------------------------------- MC148CHANNEL ACTIVATION ACK

---------------------------------------------->IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- Start T3101<------------(AGCH)------------- MC8B

SABM (PAGING RESP)-------------(SDCCH)-----------> ESTABLISH IND (PAGING RESP)

UA (PAGING RESP) ----------------------------------------------> Stop T3101<-----------(SDCCH)------------- MC01

CR (COMPLETE L3 INFO)---------------------------------->

stop T3113CC

<----------------------------------

26

1.51

2.3 Typical call failures Radio Link Establishment - Paging

RLE > PagingMC8A=C8A

1.52

2.3 Typical call failures Radio Link Establishment - RACH counter

RLE > RACHMC8C=C8C

27

1.53

2.3 Typical call failures Radio Link Establishment - OC success counters split

RLE > success MO splitMC02x=C02x

MC02 = MC02A+MC02B+MC02C+…….+MC02G+MC02H+MC02i

MC02A: LU

MC02B: SMS

MC02C: SS

MC02D: LU follow-on

MC02E: CR

MC02F: unknown

MC02G: IMSI Detach

MC02H: EC or NC

MC02i: LCS

B8

NewB8

1.54

2.3 Typical call failures LCS

LCS function (linked to MC02i) and other counters …t LCS allows to access the MS location provided by the BSS.l On MS request to know its own location (MC02 impacted,

see the previous slide)l On network request (especially during Emergency calls)l On external request (LCS Client)

t Positioning methods provided can be:

l Cell-ID or Cell-ID + TA (Timing Advance)l Conventional (standalone) GPSl Assisted GPS (with the help of A-GPS server to compute location)

èMS based (MB): MS is able to perform a pre computation

èMS assisted (MA): MS sends info, Network computes

B8

28

1.55


LCS function: Architecture

B8

SMLCBTS

BTS

MS

BSC

MSC

HLR

GMLC

OSP

Lg

Lh

ExternalLCS client

LeA

Abis

Abis

Lb

SMLC function integrated in MFS:

- receives the loc. Request from the GMLC through the MSC/BSC

- Schedules all the necessary actions to get MS location

- Computes MS location

- Provides the result back to the GMLC

MFSA-GPS server

SAGI

GPS reference network

LCS: Location ServicesSMLC: Serving Mobile Location CenterGMLC: Gateway Mobile Location CenterA-GPS: Assisted GPS

Where is my son?

Where am I?

Where is the accident? Emergency call

MS Request

Network Request

External Request

2

1

3

3

2

1

1.56


Example: Mobile terminated location request failure / success (External request)

B8

SMLCMS BSCBTS LCS ClientMSC

BSSAP-LE Perform_Location_Request

.

GMLC

BSSMAP Perform_Location_Request

BSSAP-LE Perform_Location_Response

BSSMAP Perform_Location_Response

BSSMAP Clear Command and Release

Adequat positionning method chosen by SMLC

HLR

Paging

Authentication + Ciphering

LCS Service Response

LCS Service Request

Send_Routing_Info rqst

Send_Routing_Info resp

Provide_Subscriber_Location

Provide_Subscriber_Location Result

MC923a

MC923b

MC923d

MC923cBSSAP-LE Perform_Location_Response (failure)

BSSMAP Perform_Location_Response (failure)

BSSMAP Perform_Location_Abort

Failure

Success

29

1.57


See comments for details about LCS counters located in MFS

B8

1.58

2.3 Typical call failures Radio Link Establishment - SDCCH congestion failure

SDCCH ACCESS FAILURE

SDCCH congestionSDCCH congestion

SDCCH RF access failureSDCCH RF access failure

SDCCH access failure BSS pbSDCCH access failure BSS pb

Main failure cases for Radio Link Establishment

30

1.59

2.3 Typical call failures Radio Link Establishment - SDCCH congestion

RLE > SDCCH congestion

The Immediate Assignment Reject mechanism can be disabled at OMC-R levell And is not activated for answer to paging l If disabled, no answer to the MS

t The MS will repeat automatically its request in case of congestion (next slides)l Waiting for T3122 expiry in case of Immediate Assignment Rejectl Waiting for T3120 expiry otherwise

MS BTS BSCMSC


----------------------------------------------> MC8CNo free SDCCH !!MC04

IMMEDIATE ASSIGN COMMAND<----------------------------------------------

IMM. ASS. REJECT (immediate assignment reject) MC8D, and MC8B<-------------(AGCH)------------

1.60

2.3 Typical call failures Radio Link Establishment - SDCCH congestion counter

RLE > SDCCH congestionMC04=C04

31

1.61

2.3 Typical call failures Radio Link Establishment - SDCCH cong. consequence

RLE > SDCCH congestionMAIN CONSEQUENCESt The MS will try "max_retrans +1 " time before giving up

l Immediately for phase 1 MSl After T3126 for phase 2 MS (still waiting for Immediate Assignment

during this timer)

t In case of "max_retrans+1" failures, the MS willl Either try an automatic cell reselectionl Or do nothing

t In case of LU, the MS will attempt a new LU requestt In case of Call establishment, the MS will not re-attempt automatically, it is up

to the subscriber to try to set up the call again

1.62

2.3 Typical call failures Radio Link Establishment - SDCCH cong. causes


MAIN CAUSES

t Too much SDCCH "normal" traffic for cell SDCCH designl Radio resource capacity not sufficient (too many calls)l Inadequate LA design (too many LUs)

t "Common Transport Effect"l Difficult to avoid for small cells

t Abnormal SDCCH trafficl ”Phantom" channel requests (seen in SDCCH RF failure session)l Neighboring cell barred

32

1.63

2.3 Typical call failures Radio Link Establishment - SDCCH cong. Resolution?


DYNAMIC SDCCH ALLOCATION

t Defining too many SDCCHs will lead to a lack of TCH resources... and money. t Defining too few SDCCH channels will result in SDCCH congestion. TCH channels

cannot be allocated and, once again, the operator 's revenue decreases. t At OMC-R level, it is possible to configure:

l a set of static SDCCH/x timeslots to handle normal SDCCH traffic;l a set of dynamic SDCCH/8 timeslots, which can be used for TCH traffic, or for

SDCCH traffic depending on the need.t With the "Dynamic SDCCH allocation" feature, the BSS is automatically looking after

varying SDCCH traffic and is particularly adapted to the situations such as: change of LA, change of SMS traffic model, SDCCH traffic varying due to LCS.

t This feature is particularly useful in very dense (hierarchical) networks, where the effort to optimize the SDCCH configuration becomes more important.

B8

1.64

2.3 Typical call failures Radio Link Establishment - SDCCH cong. Resolution?


DYNAMIC SDCCH ALLOCATION

B8

CHANNEL REQUESTCHANNEL REQUIRED

MS BTS BSC

(RACH)

If No free SDCCH, thenrun dynamic SDCCH/8 timeslot allocationalgorithm. If allocation is successful, then

activate dynamic SDCCH sub-channel and serve request

If allocation was unsuccessful, then reject SDCCH request (possiblyusing the Immediate Assignment Reject procedure).

MC801a&b

MC802a&b

33

1.65

2.3 Typical call failures Radio Link Establishment - SDCCH radio failure

TYPICAL CALL FAILURES






1.66

2.3 Typical call failures Radio Link Establishment - SDCCH radio access failure

RLE > SDCCH RF Failure

MS BTS BSC MSCCHANNEL REQUEST

-------------(RACH)------------> CHANNEL REQUIRED----------------------------------------------> MC8C

CHANNEL ACTIVATION (SDCCH)<---------------------------------------------- MC148

CHANNEL ACTIVATION ACK---------------------------------------------->IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- start T3101<------------(AGCH)------------- MC8B

IMMEDIATE ASSIGN-------(SDCCH)-----X

T3101expiry->“radio failure”MC149

34

1.67

2.3 Typical call failures Radio Link Establishment - real radio problems


Main causes > real radio problems

t Unbalanced cell power budgett Bad coverage (for example a moving car)t Interference (for example downlink)

t In case of radio failure, the MS will retry as for SDCCH congestion

1.68

2.3 Typical call failures Radio Link Establishment - Ghost RACH (1/7)


Main causes > "Phantom/Ghost/Spurious/Dummy ... RACH"

t Channel request received but not sent: 3 causesl Noise decodingl Reception of channel request sent to a neighboring celll Reception of HO_ACCESS sent to a neighboring cell

35

1.69

2.3 Typical call failures Radio Link Establishment - Ghost RACH (2/7)


Main causes > "Phantom/Ghost/Spurious/Dummy ... RACH"t Example of a channel required message

1.70

2.3 Typical call failures Radio Link Establishment - Ghost RACH causes (3/7)


Main causes > "Phantom RACH" >noise decoding

t GSM 05.05: " 0.02 % of Rach Frame can be decoded without error without real input signal"l BCCH not combined: 51 Rach/Multi Frame > (3600 * 1000) ms / 4.615 ms at 0.02 %: 156

dummy RACH/hourl BCCH combined: 27/51 RACH/Multi-Frame > 83 dummy RACH/hourl 3/8 of causes (field of channel request, 5 valid causes over 8) will be unvalidl Example of induced SDCCH traffic: (5/8*156*T3101 (3 sec))/3600 = 0.08 Erlang SDCCH

è This extra-load has no impact for the system

t Some tips: l Dummy Rach load depends on minimum level for decoding configured in

Evolium BTSl During period with low real traffic (night), high rate of dummy RACHl For dummy RACH, the channel required has a random value of TA

36

1.71



Main causes > "Phantom RACH" >noise decoding

t No subscriber -> no impact for subscribert But MC149 incremented -> SDCCH RF access failure is impacted

MS BTS BSC MSC

CHANNEL REQUIRED----------------------------------------------> MC8C


CHANNEL ACTIVATION ACK---------------------------------------------->

IMMEDIATE ASSIGN COMMANDIMMEDIATE ASSIGN <---------------------------------------------- start T3101

<------------ (AGCH) ------------- MC8B

T3101expiry->“radio failureMC149

1.72



Main causes > "Phantom RACH" > Channel Request sent to the neighboring cell

t Subscriber not impacted (real transaction performed elsewhere)

t But MC149 incremented -> SDCCH RF access failure is impacted

t Usual radio planning rules are sufficient to avoid the trouble

l 2 cells must not have same (BCCH, BSIC) couple

M S B T S B S C M S C

C H A N N E L R E Q U IR E D- -- -- - -- -- -- -- -- - -- -- -- -- - -- -- -- -- -- - -- -- -- -- - > M C 8 C

C H A N N E L A C T IV A T IO N (S D C CH )< - -- -- -- - -- -- -- -- - -- -- -- -- -- - -- -- -- -- -- - -- -- -- - M C 1 4 8

C H A N N E L A C T IV A T IO N A C K- -- -- - -- -- -- -- -- - -- -- -- -- - -- -- -- -- -- - -- -- -- -- - >

IM M E D IA T E A S S IG N C O M M A N DIM M E D IA T E A S S IG N < - -- -- -- - -- -- -- -- - -- -- -- -- -- - -- -- -- -- -- - -- -- -- - s ta rt T 3 1 0 1 M C 8 B

< - -- -- - -- -- -- (A G C H )-- -- - -- -- -- --

T 3 1 0 1 e x p ir y M C 1 4 9-> “ ra d io f a ilu re

37

1.73



Main causes > "Phantom RACH" > Channel Request due to handover

t During HO, the first message sent to the target cell is HO Accesst This message is an Access Burst like Channel Request

t If received on BCCH, can be understood as a Channel Request (RACH)

t A new case of "Phantom RACH"

1.74



Main causes > "Phantom RACH" > Channel Request due to handover

This case is the most dangeroust The MS sends usually a sequence of HO Access message, every framet In some cases, this can create a phantom RACH if

l The frequency of the TCH is identical or adjacent to the one of interfered BCCH

t Characteristics of such phantom RACH (Channel Required)l Subsequent frame numberl Random, but stable timing advance

t Can block very easily SDCCH

38

1.75

2.3 Typical call failures Radio Link Establishment - BSS failure

TYPICAL CALL FAILURES






1.76

2.3 Typical call failures Radio Link Establishment - BSS problem

RLE > BSS problem

t No specific counter

MS BTS BSC MSCCHANNEL REQUEST

-------------(RACH)------------> CHANNEL REQUIRED----------------------------------------------> MC8C


CHANNEL ACTIVATION ACK---------------------------------------------->IMMEDIATE ASSIGN COMMAND

IMMEDIATE ASSIGN <---------------------------------------------- start T3101<------------(AGCH)------------- MC8B

SABM (L3 info)------------(SDCCH)------------>

39

1.77

RLE counters

2.3 Typical call failures Radio Link Establishment - counters

Request MC8C

GPRS causes P62CGSM invalid causes unknown

Preparation GSM valid causes unknown

Congestion MC04BSS Pb unknown

Execution Attempt MC148

Radio Access Failure MC149BSS Pb MC148 - (MC01+MC02) - MC149

Success MC01+MC02

Radio Link Establishment

REQUEST

Congestion

ATTEMPT

Radio access failure

SUCCESS

BSS problem

Preparation Failure

Execution Failure

GPRS causes GSM/GPRS invalid causes GSM valid causes

BSS problem

1.78

2.3 Typical call failures Radio Link Establishment - indicators

TYPICAL CALL FAILURES: RLE indicators

40

1.79

2.3 Typical call failures SDCCH phase - OC success

Successful SDCCH phase: OC call

t transparent message: no dedicated counters

MS BTS BSC MSCSDCCH Phase : Originating Call case

< -------------------------------------------------------------------------------------------------------------------------AUTHENTICATION REQUEST

------------------------------------------------------------------------------------------------------------------------- >AUTHENTICATION RESPONSE

< -------------------------------------------------------------------------------------------------------------------------CIPHERING MODE COMMAND

------------------------------------------------------------------------------------------------------------------------- >CIPHERING MODE COMPLETE

------------------------------------------------------------------------------------------------------------------------- >SETUP

< -------------------------------------------------------------------------------------------------------------------------CALL PROCEEDING

1.80

2.3 Typical call failures SDCCH phase - TC success

Successful SDCCH phase: TC call


MS BTS BSC MSCSDCCH Phase : Terminating Call case





< -------------------------------------------------------------------------------------------------------------------------SETUP

------------------------------------------------------------------------------------------------------------------------- >CALL CONFIRM

41

1.81

2.3 Typical call failures SDCCH phase - LU success

successful SDCCH phase: Location Update


MS BTS BSC MSCSDCCH Phase : Location Update Case (with TMSI reallocation)

------------------------------------------------------------------------------------------------------------------------- >LOCATION UPDATE REQUEST





< -------------------------------------------------------------------------------------------------------------------------LOCATION UPDATE ACCEPT

------------------------------------------------------------------------------------------------------------------------- > TMSI REALLOCATION COMPLETE

1.82

2.3 Typical call failures SDCCH phase - drops

SDCCH phase

t Loss of connection during SDCCH phase = "SDCCH drop"

t 3 origins of SDCCH dropl Radio problems when connected on SDCCHl BSS problemsl Call lost during an SDCCH HO (handover failure without

reversion to old channel)

42

1.83

2.3 Typical call failures SDCCH phase - radio drop

SDCCH phase > drop radio

t Connection lost due to radio problem

MS BTS BSC MSCSDCCH Phase established

Radio connection lost---------------------------------------------------- > MC138CONNECTION FAILURE INDICATION

(cause : radio link failure)--------------------------------------- >CLEAR REQUEST

Cause : radio interface failure

1.84

2.3 Typical call failures SDCCH phase - BSS drop

SDCCH phase > drop BSS

t Connection lost due BSS problem


MC137

--------------------------------------- >CLEAR REQUEST

Cause : O&M interventionCause : radio interface failure

43

1.85

SDCCH phase > drop HO

l Connection lost during HandOver


HO FAILURE WITHOUT REVERSION MC07--------------------------------------- >

CLEAR REQUESTRadio Interface Message Failure (Alcatel)

2.3 Typical call failures SDCCH phase - HO drop

1.86

SDCCH phase counters

2.3 Typical call failures SDCCH phase - counters

SDCCH connection MC01+MC02+MC10

SDCCH Drop Drop radio MC138Drop BSS MC137Drop HO MC07

SDCCH Phase

TCH assignment phase SDCCH drop

SDCCH connection

Normal release

Drop radio

Drop BSS

Drop HO

44

1.87

2.3 Typical call failures SDCCH phase - indicators

SDCCH phase indicators

1.88

2.3 Typical call failures SDCCH phase - exercise

SDCCH phase: Exercises

t With K1205 (file PAIB29.REC)ü Extract a location update

(successful case)ü Extract a transaction with an

SDCCH dropWhat is the cause of the failure? Is it possible to "guess" the type of transaction (OC,

TC, LU,etc)?

ü As 2, but for a different cause

Time allowed: 15 minutes

45

1.89

2.3 Typical call failures TCH assignment - success

TCH assignment success case

t T3107: guard timer for TCH assignment

MS BTS BSC MSCTCH ASSIGNMENT PHASE (OC or TC)

< -----------------------------------ASSIGNMENT REQUEST

< --------------------------------------------------------PHYSICAL CONTEXT REQUEST

-------------------------------------------------------- >PHYSICAL CONTEXT CONFIRM

< -------------------------------------------------------- MC703CHANNEL ACTIVATION (TCH)

-------------------------------------------------------- >CHANNEL ACTIVATION ACKNOWLEDGE

< ----------------------------------------------------------------------------------- Start T3107 (SDCCH) ASSIGNMENT COMMAND

---------------------- >TCH SABM -------------------------------------------------------- >

< ---------------------- ESTABLISH INDICATIONUA

----------------------------------------------------------------------------------- > Stop T3107ASSIGNMENT COMPLETE MC718

----------------------------------- >ASSIGNMENT COMPLETE

MC140a

MC140b

B8

MC460a New B8

MC140a

MC140b

MC460a

(see comments)

1.90

TCH assignment > congestion

t 5 causes of congestion ⇒ 5 counters: C612A, B, C, D, E wheneverå Queuing is not allowedå Queue is Fullå T11 expireså RTCH request is removed from the queue due to a higher priority

request to be queuedå No Abis-TCH resource is available (Restriction in B8)


< -----------------------------------------------ASSIGNMENT REQUEST

No RTCH available on requested cell MC812

------------------------------------------------ >ASSIGNMENT FAILURE

Cause No Radio Resource Available

2.3 Typical call failures TCH assignment - TCH congestionB8 (See comments)

46

1.91

TCH assignment > radio failure

t Radio problemMS BTS BSC MSC

TCH ASSIGNMENT PHASE (OC or TC)< -----------------------------------ASSIGNMENT REQUEST






SABM----(TCH)------X

T3107 ExpiryMC746B----------------------------------- >

ASSIGNMENT FAILURERadio interface failure

2.3 Typical call failures TCH assignment - radio failure

MC140a

MC140b

1.92

TCH assignment > BSS problem

t BSS problem (Abis, BTS/BSC HW or SW)

2.3 Typical call failures TCH assignment - BSS problem








SABM----(TCH)---- >

MC14B

MC140a

MC140b

No specific counter

B8

47

1.93

TCH assignment counters

2.3 Typical call failures TCH assignment - counters

Congestion

ATTEMPT

Radio access failure

SUCCESS

BSS problem

Preparation Failure

Execution Failure

REQUEST

BSS problemTCH Assignment

Preparation Request MC140a

Congestion MC812

BSS Pb MC140a-MC140b-MC812

Execution Attempt MC140b

Radio Access Failure MC746b

BSS Pb MC140b-MC718-MC746b

Success MC718

B8

NewB8

BSS PB

discrimination

1.94

TCH Assignment indicators

2.3 Typical call failures TCH assignment - indicators

48

1.95

TCH assignment failure

t With K1205 (file PAIB29.REC)ü Find and extract a case of TCH

congestion (if any)ü Find and extract a case of

assignment failure due to radio problem (if any)

2.3 Typical call failures TCH assignment - exercise


1.96

TCH phase

t Transparent messages for BSS, no specific counterst TCH DROP: any problems occurring after TCH assignment (during or after

connection) cannot be discriminated

MS BTS BSC MSCAlerting Connection Phase (OC case) : ringing phase

< ---------------------------------------------------------------------------------------------------------------------------ALERTING

< ---------------------------------------------------------------------------------------------------------------------------CONNECT

--------------------------------------------------------------------------------------------------------------------------- >CONNECT ACK

MS BTS BSC MSCAlerting Connection Phase : TC case

--------------------------------------------------------------------------------------------------------------------------- >ALERTING

--------------------------------------------------------------------------------------------------------------------------- >CONNECT

< ---------------------------------------------------------------------------------------------------------------------------CONNECT ACK

2.3 Typical call failures TCH phase - success

49

1.97

TCH phase > drop radio

t Radio problem

MS BTS BSC MSCAlerting Connection Phase or Communication : at any time

Radio problem-------------------------------------------------------- > MC736

CONNECTION FAILURE INDICATION --------------------------------------- >Cause radio link failure CLEAR REQUEST

Cause radio interface failure(alcatel)

2.3 Typical call failures TCH phase - radio drop

1.98

TCH phase > drop TC

t Remote TransCoder problem


Radio problem-------------------------------------------------------- > MC739

CONNECTION FAILURE INDICATION --------------------------------------- >Remote transcoder failure CLEAR REQUEST

Equipment failure

2.3 Typical call failures TCH phase - remote TC drop

50

1.99

TCH phase > drop BSS internal

t Other internal BSS problem (excluding TC)


MC14C--------------------------------------- >

CLEAR REQUESTO&M intervention

Radio interface failure

2.3 Typical call failures TCH phase - BSS internal drop

1.100

TCH phase > drop HO

t Handover failure


HO FAILURE WITHOUT REVERSION MC621--------------------------------------- >

CLEAR REQUESTRadio Interface Message Failure (Alcatel)

2.3 Typical call failures TCH phase - HO drop

51

1.101

TCH phase > drop preemption

t TCH preempted

MS BTS BSC MSCAlerting Connection Phase of a call

with priority level pl2 and preemption vulnerability indicator pvi=1no TCH free

ASSIGNMENT REQUEST<---------------------------------------

Priority level pl1 > pl2preemption capability indicator pci=1

MC921C--------------------------------------- >

CLEAR REQUESTpreemption

2.3 Typical call failures TCH phase - preemption drop

1.102

TYPICAL CALL FAILURES: TCH phase counters

2.3 Typical call failures TCH phase - counters

TCH connection MC718+MC717A+MC717B

Outgoing HO success MC712

Call drop Drop radio MC736Drop TC MC739Drop internal BSS MC14CDrop HO MC621Drop preemption MC921C

Normal release unknownNSS abnormal release unknown

TCH Phase

Outgoing HO success Call drop

TCH connection

Normal release

Call drop radio

Call drop BSS

Call drop HO

Call drop preemption

TC

BSS internal

NSS abnormal release

52

1.103

TYPICAL CALL FAILURES: TCH phase indicators

t Call drop rate = call drop / RTCH success end

t RTCH success end = RTCH assignment success + RTCH incoming (HO+DR) success - RTCH outgoing HO

2.3 Typical call failures TCH phase - call drop rate

Incoming internal HO+DR

BSS1 BSS2

Incoming external HO+DR

outgoing HO

TCH assignment

1.104


t RTCH drop rate = call drop / RTCH success begin

t RTCH success begin = RTCH assignment success+ RTCH incoming (HO+DR) success- RTCH intra cell HO success

2.3 Typical call failures TCH phase - RTCH drop rate

BSS1 BSS2


TCH assignmentIncoming external HO+DR

outgoing HO

Intra-cell HO

53

1.105


t TRX TCH drop rate = call drop / RTCH success

t RTCH success = RTCH assignment success+ RTCH incoming (HO+DR) success

2.3 Typical call failures TCH phase - TRX TCH drop rate


TCH assignment

outgoing HOBSS1 BSS2

Incoming external HO+DRIntra-cell HO

1.106

TYPICAL CALL FAILURES: TCH phase indicatorst See comments

2.3 Typical call failures TCH phase - indicators

54

1.107

Alerting/Connection phase: TCH dropt With K1205 (file PAIB29.REC)

ü Find a TCH drop, find the causeCan you tell if it is occurring during thecommunication phase?

ü Find a TCH drop due to handover, extract the callü Find a TCH drop due to BSS problem,

extract the call, identify PCM, CICü As 3, next case

Any remark?

2.3 Typical call failures TCH phase - exercise


1.108

TYPICAL CALL FAILURES: summary

call stage A interface cause field related problem

radio linkestablishment

no message - - SDCCH congestion- radio problem- dummy rach

SDCCH phase Clear Request - radio interface failureradio interface failure- O&M intervention

- radio problem- BSS system HW/SW pb- recovery/operator

TCH assignment Assignment Failure - no radio resource avalaible- Radio Interface Failure

- TCH congestion- Radio problem

Alerting/connectioncall established

Clear Request - radio interface failureradio interface message failure- equipment failure- O&M interventionradio interface failure-preemption

- radio problem- HO failure w/o reversion- Transcoderfailure- operator action/recovery

- BSS system HW/SW pb- preemption

2.3 Typical call failures summaryB8 (See comments)

NewB8 New LAPD counter to analyze the cause of call establishment failures

55


2 GLOBAL INDICATORS

2.4 Description of global indicators

1.110

2.4 Description of global indicatorsrecall

t Global Indicators arel A set of indicators selected by Alcatel l Useful to monitor the overall network

üWhat are the user and or system impacts if a GI is bad?

56

1.111

t SDCCH CONGESTION rate: may have impact for subscriberl Call setup failure only after 3 subsequent congestionsl If not, only some extra delay for call establishment

è (less than 1 second) without immediate_assign_rejectè Can be longer with reject (but usually short values are used for call

request)

2.4 Description of global indicatorsSDCCH congestion rate

INDICATOR(G)

SDCCH ASSIGN CONG FAIL RATE

DEFINITION Rate of SDCCH not allocated during radio link establishment procedure due to congestion on the Airinterface

FORMULA B7.2 Σ cell (MC04) / SDCCH ASSIGN REQUESTSTHRESHOLD > 5%COMMENT Check SDCCH Erlang : if not critical, SDCCH availability/allocation problem, or HO access on a

nearby cell side effect or interference on the carrier handling SDCCH (the last 2 can lead to highrate of « phantom RACH »)

REF NAME SDNACGR UNIT %

1.112

DESCRIPTION OF GLOBAL INDICATORSt SDCCH CONGESTION rate

2.4 Description of global indicatorsSDCCH congestion rate

57

1.113

t SDCCH DROP ratet User impact: call setup failure

2.4 Description of global indicatorsSDCCH drop rate

INDICATOR(G)

SDCCH DROP RATE

DEFINITION Rate of dropped SDCCH (SDCCH is established for any transaction OC, TC, LU,etc.)FORMULA B7.2 Σcell (MC138 + MC07 + MC137) / SDCCH ASSIGN SUCCESSTHRESHOLD > 4%COMMENT Drop radio + Drop HO + Drop BSSREF NAME SDCDR UNIT %

1.114

t TCH ASSIGN UNSUCCESS rate: l congestionl radio probleml BSS problems

2.4 Description of global indicatorsTCH assign unsuccess rate

INDICATOR(G)

TCH ASSIGN UNSUCCESS RATE

DEFINITION Rate of unsuccessful RTCH seizures for normal assignment purpose (congestion + HO&radiofailures)

FORMULA B7.2 (TCH ASSIGN REQUESTS – TCH ASSIGN SUCCESS) / TCH ASSIGN REQUESTSTHRESHOLD > 3%COMMENTREF NAME TCNAUR UNIT %

58

1.115

t GLOBAL RADIO CONGESTION LEVEL (TCH congestion rate)l Subscriber impact: call setup failurel More a management indicator: % of network which has congestion

S2: GLOBAL 2.4 Description of global indicatorsGlobal radio congestion level

INDICATOR(G)

GLOBAL RADIO CONGESTION LEVEL

DEFINITION Global radio congestion level : number or rate of cells recurrently congestedFORMULA B7.2 COUNT_OF_CELLS (AVERAGE (MAX (TCH ASSIGN FAIL CONG RATE)) > 2%))THRESHOLD According to operatorCOMMENT This indicator reports the global radio congestion rate on the network. We define a specific

indicator counting the number of cells that are in congestion in a recurrent manner.MAX (TCH ASSIGN FAIL CONG RATE) : is the peak of failures due to congestion observedduring the period (the day normally). See the definition of TCH ASSIGN FAIL CONG RATE in theQuality of Service chapter)AVERAGE : is an averaging function of the blocking rate over the selected period, that is over BHof days for a week, or over BH of weeks for a monthCOUNT_OF_CELL : is a function counting the number of cells for which condition between () isrespected.The number of cells can be used as indicator, or the rate of cells over the total number of cells in thenetwork or area.

REF NAME QSCGR UNIT Number

1.116

t CALL DROP rate: The most important indicatorl Used with call setup success rate to compare PLMN (GSM and other

one)l Subscribers impact: call drop!!

2.4 Description of global indicatorsCall drop rate

INDICATOR(G)

CALL DROP RATE

DEFINITION Rate of dropped calls (system + radio+ HO + preemption) over the total amount of calls with asuccessful end

FORMULA B7.2 Σcell (MC621 + MC14c + MC736 + MC739 + MC921c) / TCH SUCCESS ENDTHRESHOLD > 4%COMMENT Drop system + Drop radio + Drop HO + Drop preemption

TCH drops occurring after successful assignment but before speech connection are considered ascall drops even if from the customer point of view it is a call setup failureMC739, MC736 and MC621 derive from B6 counters C139, C136 and C21. These new countersare per TRXMC921c is new in B7.2

REF NAME QSCDR UNIT %

59

1.117

t CALL SETUP SUCCESS rate: the second most important indicatorl Used to compare PLMNl Subscriber: call not established at the first attempt

t Beware: call setup failures due to a lack of coverage are not taken into account in this indicator!!

è No way to quantify them (as there is no initial access)

2.4 Description of global indicatorsCall setup success rate

INDICATOR(G)

CALL SETUP SUCCESS RATE (BSS view)

DEFINITION Rate of calls going until TCH successful assignment, that is not interrupted by SDCCH DROPneither by Assignment failures

FORMULA B7.2 (1 – ( SDCCH DROP / SDCCH ASSIGN SUCCESS ) ) * (1 TCH ASSIGN UNSUCCESS RATE)THRESHOLD > 95%COMMENT SDCCH assignment failures are not considered in CSSR as :

• ghost (spurious) RACH cannot be discriminated from a real access failure• effect of re-attempts performed autonomously by the MS cannot be quantified

REF NAME QSCSSR UNIT %

1.118

t 1 call success =l 1 call successfully establishedl Without any call drop

2.4 Description of global indicatorsCall success rate

INDICATOR(G)

CALL SUCCESS RATE (BSS view)

DEFINITION Rate of calls going until normal release , that is not interrupted by SDCCH DROP, neither byAssignment Failures nor by CALL DROP

FORMULA B6.2 (CALL SETUP SUCCESS RATE) * (1 – CALL DROP RATE)THRESHOLD < 92%COMMENTREF NAME QSCCR UNIT %

60

1.119

t CALL SETUP SUCCESS rate t CALL SUCCESS rate

2.4 Description of global indicatorsCall (setup) success rate

1.120

2.4 Description of global indicatorsHandover cause distribution

t Indicator aiming at measuring the efficiency of planning /optimization

INDICATOR(G)

HO CAUSE DISTRIBUTION

DEFINITION Distribution of Handover attempts by cause X : UL/DL Qual, UL/DL Lev, UL/DL Interference,Distance, Better Cell, Interband, Micro cells HO, Concentric cell, Traffic, AMR, TFO causes.

FORMULA B7.2 Σ cell (MC67w or MC785x or MC586y or MC10zz or MC447 or MC461)Σcell (MC67all + MC785all + MC586all + MC10all + MC447 + MC461)

MC67all = MC671+MC672+MC673+MC674+MC675+MC676+MC677+MC678+MC679+MC670MC785all = MC785a + MC785d + MC785e + MC785f (microcell)MC586all = MC586a + MC586b + MC586c (concentric)MC10all = MC1040 + MC1044 + MC1050

THRESHOLD Quality DL > 10%, Qual UL > 10%, Level UL > 20%, Level DL > 20%Interf UL > 5%, Interf DL > 5%, Better Cell < 30%

COMMENTREF NAME HCSTBPBR, HCCCELVDR, HCCCELVUR, HCCCBCPR,

HCSTEDIR, HCSTEIFDR, HCSTELVDR, HCSTEQLDR,HCSTBDRR, HCMBBCPR, HCMCEBSR, HCMCELVDR,HCMCBCPR, HCMCELVUR, HCSTEMIR, HCSTEIFUR,HCSTELVUR, HCSTEQLUR, HCSTAMR, HCSTBTFR

UNIT %

61

1.121

2.4 Description of global indicatorsHandover standard cause distribution

t Indicator aiming at measuring the efficiency of planning / optimizationt Interesting for comparing HO distribution after concentric or micro cell

implementation

INDICATOR(G)

DISTRIBUTION HO CAUSE STANDARD

DEFINITION Distribution of Handover attempts by standard cause : Power Budget, quality too low, level too low,high interference and MS-BTS distance too long.

FORMULA B7.2Σ cell ( (MC67x) / GLOBAL HO CAUSE STANDARD)

MC67x = MC670 or MC672 or MC671 or MC673 or MC676 or MC677 or MC678 or MC674 or(MC670+MC672) or (MC671+MC673) or (MC676+M677)

THRESHOLDCOMMENTREF NAME HCSTEIFDSR, HCSTEIFUSR, HCSTEIFSR, HCSTELVDSR,

HCSTELVUSR, HCSTELVSR, HCSTEQLDSR,HCSTEQLUSR, HCSTEQLSR, HCSTBPBSR, HCSTEDISR

UNIT %

1.122

2.4 Description of global indicatorsHandover cause distribution

t HANDOVER CAUSE rates

62

1.123

t Global success rate of Outgoing HO

t Success rate of execution of Outgoing HO

2.4 Description of global indicatorsOutgoing handover success rate

INDICATOR(G)

OUTGOING HO SUCCESS RATE

DEFINITION Rate of successful outgoing external and internal intercell SDCCH and TCH handoversFORMULA B7.2 Σcell (MC646 + MC656) / Σcell (MC645a + MC655a)THRESHOLD < 90%COMMENT This indicator includes preparation and execution.REF NAME HOORSUR UNIT %

INDICATOR(G)

EFFICIENCY OF OUTGOING HANDOVER EXECUTION

DEFINITION Rate of successful outgoing external and internal intercell SDCCH and TCH handoversFORMULA B7.2 Σcell (MC646 + MC656) / Σcell (MC650 + MC660)THRESHOLD < 90%COMMENT This indicator takes into account HO execution only (not ho preparation).REF NAME HOOREFR UNIT %

1.124

t Global success rate of Incoming HO

t Success rate of execution of Incoming HO

2.4 Description of global indicatorsIncoming handover success rate

INDICATOR(G)

INCOMING HANDOVER SUCCESS RATE

DEFINITION Rate of successful incoming external and internal intercell SDCCH and TCH handovers.FORMULA B7.2 Σcell (MC642 + MC652) / Σcell(MC820 + MC830)THRESHOLD < 90%COMMENTREF NAME HOIRSUR UNIT %

INDICATOR(G)

EFFICIENCY OF INCOMING HANDOVERS

DEFINITION Rate of successful incoming external and internal intercell SDCCH and TCH HOsFORMULA B7.2 Σcell (MC642 + MC652) / Σcell (MC821 + MC831)THRESHOLD < 90%COMMENT Excluding congestion failures and BSS preparation failures from requests.REF NAME HOIREFR UNIT %

63

1.125

t The highest, the best is the cellt But the traffic handled is not taken into account

2.4 Description of global indicatorsCall quality factor absolute

INDICATOR(G)

CELL QUALITY FACTOR ABSOLUTE

DEFINITION Indicator summarizing the cell behavior and allowing the operator to sort out cell for investigation.This indicator is based on failure events. For each part of the indicator,twothresholds are used: Topt and TQoS. TQoS is the QoS warning threshold (e.g. above or

belowthe threshold, a warning is generated on the cell. Topt + TQoS is the optimal valuethat should be acheived. Each part as a weighting factor (WF) according to the

impact on the subscriber’s point of view.

investigation. This indicator is based on failure events. For each part of the indicator, two

FORMULA B6.2 ((1 – SDCCH CONGESTION rate) - TQoS)/ Topt * WF+ (CALL SETUP SUCCESS rate - TQoS)/ Topt *WF+ ((1 – CALL DROP rate - TQoS)/ Topt * WF+ (OUTGOING HO SUCCESS rate - TQoS)/ Topt * WF+ ((1 – HO QUALITY rate - TQoS)/ Topt * WF

THRESHOLD SDCCH CONGESTION rate : TQoS = 0.97, Topt = 0.03, WF = 0.1CALL SETUP SUCCESS rate : TQoS = 0.9, Topt = 0.09, WF = 0.2CALL DROP rate : TQoS = 0.96, Topt = 0.04, WF = 0.3OUTGOING HO SUCCESS rate : TQoS = 0.85, Topt = 0.12, WF = 0.15HO QUALITY rate : TQoS = 0.85, Topt = 0.1, WF = 0.25

COMMENTREF NAME QSCQAR UNIT %

1.126

t For optimizationt Try to improve cells with the worst CQFR

2.4 Description of global indicatorsCall quality factor relative

INDICATOR(G)

CELL QUALITY FACTOR RELATIVE

DEFINITION This indicator is the Cell Quality Factor Absolute weighted by the cell traffic.Investigation shouldbe done in priority on the cell having a high rate of failures with high traffic (the traffic is the rate oftraffic handled by the cell over the total network traffic – traffic is TCH seizure attempts)

FORMULA B7.2 CQFA * ((MC15a + MC15b + MC703)cell / (MC15a + MC15b + MC703)network)THRESHOLD N/ACOMMENTREF NAME QSCQRR UNIT %

64

1.127

t Management indicator, maintenance oriented, assessingl Quantity of stability problemsl Reaction time to problems

2.4 Description of global indicatorsNetwork TCH availability

INDICATOR(G)

NETWORK (TCH) AVAILABILITY

DEFINITION Rate of TCHs able to carry traffic (upon the total number of traffic channels)FORMULA B7.2 (Σcell (MC250) / #Available TCH)THRESHOLD < 95%COMMENT #Available TCH : according to channel configurationREF NAME TCAVAR UNIT %

1.128

t GLOBAL INDICATORS

2.4 Description of global indicatorsExercise

Indicator value OK ? Impact

SDCCH congestion 10 % NOK difficulties to establish call

Call drop 5 %

Call success 95 %

Efficiency of outgoing HO 91 %

Network TCH availability 94 %

TCH assignment failure 2,4 %

Call drop 2,3 %

SDCCH drop 2 %

HO cause distribution(ratio of better cell)

45 %

Call success 88 %

SDCCH drop 1 %


65


2 GLOBAL INDICATORS

2.5 Traps and restrictions of global indicators

1.130

2.5 Traps and restrictions of global indicatorsObjective

t Beaware of traps and restrictions about some global indicators

t So as to be able to provide a reliable interpretation

66

1.131

2.5 Traps and restrictions of global indicatorsCall set-up success rate / Call drop rate

t CALL SETUP SUCCESS l The radio link establishment failure is not taken into account,

because: è most of failures during RLE are due to ghost RACHè the MS is attempting MAX_RETRANS+1 times before giving upè difficult to assess subscriber's impact, anyhow very low

t CALL DROPl For BSS, the last stage is considered as established,

although it is not the cause from a user point of viewl If a TCH drop occurs during this phaseè for the user, it is a setup failureè for the OMC-R indicators, counted as a call drop

1.132

2.5 Traps and restrictions of global indicatorsCall duration

IMPACT OF CALL DURATION

t The longest a call is, the highest the risk to have a drop ist If statistics are done on abnormally long or short calls, the result

can be less accurate t Typical case: drive testt Typical call duration: 80/90 seconds in most of European

countries

67

1.133

2.5 Traps and restrictions of global indicatorsMobility

IMPACT OF MOBILITYt Most of drop problems are due to mobilityl Usually 2/3 of calls are static (no HO will be done)l For example, if 40 drops are observed for 1000 calls

è 40/1000 = 4% of global call dropè but most of call drops are generated by "moving calls"ü 40/(1000*1/3) = 40/333 = 12 % of call drop rate for moving callü 0 % for static call

t Typical trap when comparing drive tests results with OMC-R statistics

1.134

2.5 Traps and restrictions of global indicatorsExercise

t TRAPS AND RESTRICTIONS OF GLOBAL INDICATORS: Case conclusion OK ? why

global call drop : 2% for 1 call of 20 mn,The risk of drop is 2%

NOK The call duration is higher than the average

In 1 BSS, some transcoders arefaulty : as soon as TCHs are

established on these TCs, they are lost

The call setupsuccessrate indicatorwill beincreased due to thisproblem

In 1 network, drive test are showinga general call drop of 7%. The OMC-R call drop indicator isgiving 2.1%.

The OMC-R indicatoris erroneous (drivetest is the reality)

In 1 network, the global call setupsuccessis 92 %

For moving calls, callsetupsuccesswill beabout 76 %

In a pedestrian zone, 80 % of callsare static

The measured call drop is 1,7 %

For taxi, calldone in Taxi in this zone will

bedroppedat 5.1 %


68


2 GLOBAL INDICATORS

2.6 Global indicators interpretation

1.136

2.6 Global indicators interpretation Exercise 1

ü Is this network OK? N a m e v a l u e

S D C C H co n g e st io n 1 %

S D C C H d r o p 3 %

T C H a ssi g n m e n t fa i l u r er a te

2 %

C a ll d r o p 1 %

C a ll se tu p su c ce ss r a te 9 6 %

C a ll su cce ss r a te 9 4 %

E f f i c i e n cy o f o u tg o in gH O

9 2 %

E f f i c i e n cy o f i n co m i n gH O

9 3 %

H O c a u se d ist r ib u t i o nb e t te r / l e v e l / q u a l i t y

7 0 / 2 0 / 1 0

N e tw o r k TC Ha v a i l a b i l i ty

9 8 %


69

1.137


t Can one say that : ü all indicators are OK? ü the coverage of the network is 95%? ü the call success of all the cells are 95%

(minimum)? N a m e v a l u e

S D C C H c o n g e s t i o n 5 %

S D C C H d r o p 2 %

T C H a s s i g n m e n t f a i l u r er a t e

1 %

C a l l d r o p 1 %

C a l l s e t u p s u c c e s s r a t e 9 7 %

C a l l s u c c e s s r a t e 9 5 %

E f f i c i e n c y o f o u t g o i n gH O

9 2 %

E f f i c i e n c y o f i n c o m i n gH O

9 2 %

H O c a u s e d i s t r i b u t i o nb e t t e r / l e v e l / q u a l i t y

7 5 / 1 5 / 1 0

N e t w o r k T C Ha v a i l a b i l i t y

9 8


1.138


t Results of field tests on a network

ü Is the network better if QSCDR = 2%?

Name value

SDCCH congestion

SDCCH drop

TCH assignment failurerateCall drop 4.6 %

Call setup success rate 92 %

Call success rate

Efficiency of outgoingHO

Efficiency of incomingHO

HO cause distributionbetter/level/qualityNetwork TCHavailability


70


3. DETAILED INDICATORS

1.140

3 Detailed indicatorsSession presentation

t Objective: to be able to use the BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS document in order to get some more detailed indicators of the Alcatel BSS

t Program: 3.1 Indicator reference name3.2 Indicators classification

71



3.1 Indicator reference name

1.142

3.1 Indicator reference nameDescription

t each QOS indicator has a unique REFERENCE NAME of 10 characters

UnitFamily

Procedure Type JokerPrefix Sub-type

mandatory

optional

72



3.2 Indicators classification

1.144

3.2 Indicators classification Main categories

t Classification in BSS - DEFINITION OF QUALITY OF SERVICE INDICATORS document

Control Channels

SCCP

TCH

SDCCH

Traffic load

Call statistics

RTCH

SDCCH

Global QoS

Couple of cells

SDCCH /TCHHO repartition

Intracell HO

Incoming HO

Outgoing HO

HO causes

Handoverstatistics

Resourceavailability

Multiband

Multilayer / MultibandNetwork

Concentric cells

Directed retry

Densificationtechniques

GSMindicators

73

1.145

3.2 Indicators classification SDCCH traffic

t Traffic Load and Traffic Model > SDCCH traffic

Estab

SDCCH Traffic

TrafficMT

TrafficMO

Loc. Update

IMSI Detach

Sup. Service

Call

LU Follow on

SMS

CallRe-Estab

Other

MSPenetration Rate

TrafficDual Band

ResourceOccupancy

SDCCHErlang

SDCCH MeanHolding TimeGlobal

Traffic

GlobalRequests

TrafficModel

HandoverNormalAssignment

NormalAssignment

Handover

1.146

3.2 Indicators classification TCH traffic

t Traffic Load and Traffic Model > TCH traffic

RTCH Traffic

ResourceOccupancy

TCHErlang

Full RateErlang

Full RateAllocated

Full RateMean TCH

Time

Half RateErlang

Half RateAllocated

Half RateMean TCH

Time

Blocking Peak

Ratio ofHR Traffic

TCHMultibandOccupancy

Traffic Model

REQUESTSAssign / HO / DR

SUCCESSAssign / HO / DR

HO PER CALL

REQUESTSFR, DR, DR/EFR, AMR, DATA

Speech Version&

Channel Type

ALLOCATIONSFR, HR, EFR, AMR, DATA

SUCCESSAMR / TFO

74

1.147

3.2 Indicators classificationSCCP resource occupancy / Control channels traffic

t Traffic Load and Traffic Model > SCCP resource occupancyl SCCP traffic in Erlang

t Traffic Load and Traffic Model > Control Channels trafficl PCH channel loadl AGCH channel loadl RACH channel load

1.148

3.2 Indicators classificationQoS SDCCH

t GLOBAL Quality of service > SDCCH

Drop BSS

SDCCH

EstablishedPhase

Drop Rate

Drop Radio Drop HO

Unsuccess

Congestion

Assignment Phase/

Handover

RadioFailure

BSS Failure

Access Reject

Dynamic Allocation

B8

New B8

(See comments)

75

1.149

3.2 Indicators classificationQoS RTCH

t GLOBAL Quality of service > RTCH

DirectedRetry

RTCH

Unsuccess

Assignment Phase/

Handover

Global RadioCongestion Level

Congestion

RadioFailure

BSSFailure

EstablishedPhase

Drop rate

Drop Radio

Drop BSS

Drop HO

Preemption

PreemptionPhase

PCI =1 PVI =1

Requests

Allocationwith / withoutPreemption

Failure

Success

Success

QueuingPhase

Queue Length

AssignQueuing Fail

AssignQueued

& Reject

QueuedSuccess

Queue Full

HigherPriority

Timeout

AssignQueued

NormalAssign.

1.150

3.2 Indicators classificationQoS call statistics

t GLOBAL Quality of service > Call statistics

Call Statistics

Call Success

Call SetupSuccess Rate

CallSuccess Rate

Cell QualityFactor Absolute

Cell QualityFactor Relative

Call Drop

Call Drop Rate

Drop Radio Drop BSSDrop HO

Transcoder Failure

BSS Internal Failure

Call DropEnd User Rate

Preemption

76

1.151

t Handover STATISTICS > Handover causes

3.2 Indicators classificationHandover causes

Handover causes

HO causes

All HO

cause distribution

Outgoing HO Incoming HOHO standard

cause distribution

HO cause category

distribution

HO causes per Adjacency

HO cause category

distribution

B8

Fast traffic HO taken into account

New type of counter for dual band HO

(See comments)

New B8

1.152

t Handover STATISTICS > Outgoing handovers

3.2 Indicators classificationOutgoing handovers

Failure With Reversion

Call Drop Rate

Efficiency

Preparation Success Rate

Intra-BSC


Call Drop Rate

Efficiency


External

Call Drop Rate

Efficiency

Success Rate

Intra-BSC & External

Outgoing HO

B8

New B8 New LAPD counter to analyze the cause of delay in HO procedures

77

1.153

t Handover STATISTICS > Incoming handovers

3.2 Indicators classificationIncoming handovers

Failure BSS

Failure Radio

Congestion

Efficiency

Intra-BSC

Failure BSS

Failure Radio

Failure No CIC

Congestion

Efficiency

External

Efficiency

Intra-BSC & External

Incoming HO

B8

New counters and indicators for:

Incoming external HO 3G - > 2G

Incoming external HO 2G - > 2G only

New B8

(See comments)

1.154

t Handover STATISTICS > Intracell handovers

3.2 Indicators classificationIntra-cell handovers

CDR Radio CDR BSS


Failure BSS

Call Drop Rate

Congestion

Efficiency

Intracell HO

78

1.155

t Handover STATISTICS > Handover statistics per couple of cell

3.2 Indicators classificationHandover statistics per couple of cells

HO Success Distribution

Success Rate

Efficiency


HO statisticsper Couple of Cell


4 HANDOVER INDICATORS

79

1.157

4 Handover indicatorsSession presentation

t Objective: to be able to explain what are the main Handover counters and indicators provided by the Alcatel BSS in order to monitor the quality of handovers

t Program: 4.1 Intra-cell handover indicators per cell4.2 Internal handover indicators per cell4.3 External handover indicators per cell4.4 Handover indicators per couple of cells



4.1 Intra-cell handover indicators per cell

80

1.159

4.1 Intra-cell handover indicators per cell Handover types

HO FAIL. CASES > HO Remindert Intra-Cell: Handover between two

TCHs of the same cellt Internal

l between two cells of the same BSCl also called intra BSCl and not using the forced external

handover mode

t Externall between two cells of different BSCsl also called inter BSCl or between two cells of the same

BSC when using the forced external handover mode

TCH/(SDCCH) Handovert Synchronous

l between 2 cellsl sharing the same clocksl collocatedl usually 2 sectors of the same BTS

è tunable at OMC-R level

t Asynchronousl not synchronous for any reasonl no dedicated monitoring for

synchronous/asynchronous HO

t Incomingl as considering the target cell

t Outgoingl as considering the serving cell

1.160

4.1 Intra-cell handover indicators per cell Intracell HO - success

HO FAIL. CASES > intracell HO > successful caseMS BTS BSC MSC

MEAS REPORT-----------------------------> MEASUREMENT RESULT

--------------------------------------------------------------> MC870PHYSICAL CONTEXT REQUEST (old channel)<--------------------------------------------------------------PHYSICAL CONTEXT CONFIRM (old channel)

-------------------------------------------------------------->CHANNEL ACTIVATION (new channel)

<--------------------------------------------------------------CHANNEL ACTIVATION ACK (new channel)

-------------------------------------------------------------->ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel) MC871

<----------------------------- <-------------------------------------------------------------- start T3107SABM

-----------------------------> ESTABLISH INDICATION (new channel)UA -------------------------------------------------------------->

<-----------------------------ASSIGNMENT CMP ASSIGNMENT COMPLET(new channel)-----------------------------> --------------------------------------------------------------> stop T3107

MC662HANDOVER

PERFORMED------------------->

RF CHANNEL RELEASE (old channel)<--------------------------------------------------------------

RF CHANNEL RELEASE ACK (old channel)-------------------------------------------------------------->

81

1.161

4.1 Intra-cell handover indicators per cell Intracell HO - failures

HO FAIL. CASES > intracell HO failures

Ø Handover Preparation: l congestion l BSS problem (no specific counter)

Ø Handover Execution: l reversion to old channell drop radiol BSS problem (no specific counter)

1.162

HO FAIL. CASES > intracell HO failure: congestionMC561TCH+MC101SDCCH

4.1 Intra-cell handover indicators per cell Intracell HO - congestion

MS Serving BTS Serving BSC MSC


--------------------------------------------------------------> MC870No free TCH

MC561

82

1.163

4.1 Intra-cell handover indicators per cell Intracell HO - radio failure ROC

HO FAIL. CASES > intracell HO failure: reversionold channel

Serving ServingMS BTS BSC MSC

MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)start T200

SABM (new channel)-----------------------------> ESTABLISH INDICATION (new channel)

----------------------------------------------------------------->UA (new channel)

X- - - - - --------------------SABM (new channel)

----------------------------->UA (new channel)

X- - - - - --------------------

SABM (old channel)-----------------------------> ESTABLISH INDICATION (old channel)

UA (old channel) -----------------------------------------------------------------><-----------------------------ASSIGNMENT FAIL ASSIGNMENT FAILURE-----------------------------> -----------------------------------------------------------------> stop T3107

MC667PHYSICAL CONTEXT REQUEST (new channel)

<-----------------------------------------------------------------PHYSICAL CONTEXT CONFIRM (new channel)

----------------------------------------------------------------->RF CHANNEL RELEASE (new channel)

<-----------------------------------------------------------------RF CHANNEL RELEASE ACK (new channel)

----------------------------------------------------------------->

1.164

HO FAIL. CASES > intracell HO failure: radio dropMC663=C63TCH+C103SDCCH


MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)

MC663Release of old and new channels T3107 expiry

4.1 Intra-cell handover indicators per cell Intracell HO - radio failure drop

83

1.165

HO FAIL. CASES > intracell HO failure: BSS drop

t no specific counter


MC871ASSIGNMENT CMD ASSIGNMENT COMMAND (old channel)<----------------------------- <----------------------------------------------------------------- start T3107 (= T10)

--------------------------------------- >CLEAR REQUEST

O&M interventionRadio interface failure

4.1 Intra-cell handover indicators per cell Intracell HO - BSS problem

1.166

HO FAIL. CASES > intracell HO counters

4.1 Intra-cell handover indicators per cell Intracell HO - counters

Request MC870

Congestion MC561+MC101BSS Pb MC870-MC871-(MC561+MC101)

Attempt MC871

Reversion old channel MC667Drop radio MC663BSS Pb MC871-MC662-MC667-MC663

Success MC662

Preparation

Execution

INTRACELL Handover

REQUEST

CONGESTION

ATTEMPT

REVERSION OLD CHANNEL

DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

84



4.2 Internal handover indicators per cell

1.168

HO FAIL. CASES > internal HO > success case

4.2 Internal handover indicators per cell Internal HO - success

The same inter-cellhandover procedure leads to an incrementation of two sets of counters: incoming HO counters for the target cell: MC830, MC831, MC652, etc.outgoing HO counters for the serving cell: MC655A, MC660, MC656, etc.In HO_PERFORMED MESSAGEt Target cell (CI,LAC)t "cause" of HO

MS serving cell target cell BSC MSCMEAS REP

-----------------------> MEASUREMENT RESULT------------------------------------------------------------------------> MC830, MC655A

CHANNEL ACTIVATION<----------------------------------

CHAN ACTIV ACK---------------------------------->

HO CMD HANDOVER COMMAND<----------------------- <------------------------------------------------------------------------ start T3103

MC831, MC660start T3124

HANDOVER ACCESS------------------------------------------------------------->-------------------------------------------------------------> HO DETECTION

PHYSICAL INFORMATION ----------------------------------><------------------------------------------------------------- start T3105stop T3124start T200------------------------ SABM ---------------------------> stop T3105<-------------------------- UA ----------------------------- ESTABLISH INDICATIONstop T200 ---------------------------------->

HANDOVER COMPLETE HO CMP stop T3103-------------------------------------------------------------> ----------------------------------> HO PERFORMED

------------------------>Release of old TCH MC652, MC656

85

1.169

HO FAIL. CASES > Incoming internal HO failures:

Handover procedure from the target cell point of view

Ø Handover Preparation: l congestion: no RTCH available in the target cell

O does not concern the outgoing side (serving cell point of view)l BSS problem (no specific counter)

Ø Handover Execution: l radio problem: the MS fails to access the new channel

O the reversion/drop discrimination concerns only the serving celll BSS problem (no specific counter)

4.2 Internal handover indicators per cell Incoming internal HO - failures

1.170

HO FAIL. CASES > Incoming internal HO fail: congestionMC551TCH+MC91SDCCH

4.2 Internal handover indicators per cell Incoming internal HO - congestion

MS Serving Cell Serving BSC MSC


--------------------------------------------------------------> MC830No free TCH

MC551MC91

If no free SDCCH

86

1.171

HO FAIL. CASES > Incoming internal HO fail: MS access problem

4.2 Internal handover indicators per cell Incoming internal HO - radio failure


-----------------------> MEASUREMENT RESULT------------------------------------------------------------------------>

CHANNEL ACT IVATION<----------------------------------

CHANNEL ACTIV ACK---------------------------------->


MC660SABM

-----------x T3103 expiry MC653

MS Serving cell Target Cell BSC


HANDOVER ACCESS MC660------------------------------------------------------------->-------------------------------------------------------------> HO DETECTION

PHYSICAL INFORMATION ----------------------------------><------------------------------------------------------------- start T3105

SABM-------------------------------------------------------------> ESTABLISH INDICATION

UA ----------------------------------><------------------------------------------------------------- stop T3105

HANDOVER COMPLETE----------------------------------------------------- - - - -X

SABM-----------------------> ESTABLISH INDICATION

UA ------------------------------------------------------------------------><-----------------------

HO FAILURE HANDOVER FAILURE-----------------------> ------------------------------------------------------------------------> MC653

Release of new channel

1.172

HO FAIL. CASES > Incoming internal HO counters

4.2 Internal handover indicators per cell Incoming internal HO - counters

Request MC830


Attempt MC831

Radio (MS access problem) MC653BSS Pb MC831-MC652-MC653

Success MC652

Execution

Preparation

INCOMING INTERNAL Handover

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

87

1.173

4.2 Internal handover indicators per cell Incoming internal HO - indicators

SUCCESS

HO FAIL. CASES > Incoming internal HO indicators

1.174

HO FAIL. CASES > Outgoing internal HO failures

Handover procedure from the serving cell point of view

Ø Handover Preparation: l congestion on the target cell (no specific counter on the serving cell)l BSS problem (no specific counter)

Ø Handover Execution: l radio problem: the MS reverts to the old channell radio problem: the MS dropsl BSS problem (no specific counter)

4.2 Internal handover indicators per cell Outgoing internal HO - failures

88

1.175

HO FAIL. CASES > Outgoing internal HO fail: reversionold channel

4.2 Internal handover indicators per cell Outgoing internal HO - radio failure ROC



HANDOVER ACCESS MC660------------------------------------------------------------->-------------------------------------------------------------> HO DETECTION



UA ----------------------------------><------------------------------------------------------------- stop T3105



UA ------------------------------------------------------------------------><-----------------------

HO FAILURE HANDOVER FAILURE-----------------------> ------------------------------------------------------------------------> MC657


1.176

HO FAIL. CASES > Outgoing internal HO fail: drop

t clear_request: ask the MSC to release the connectiont In case of call drop due to HO, the cause is "radio interface

message failure" (for Alcatel)


-----------------------> MEASUREMENT RESULT------------------------------------------------------------------------> MC655A

CHANNEL ACTIVATION<----------------------------------

CHAN ACTIV ACK---------------------------------->


MC660SABM

----------xT3103 expiryMC658

Clear_request------------------------>

Clear_commandRelease of old and new TCH <------------------------

4.2 Internal handover indicators per cell Outgoing internal HO - radio failure drop

89

1.177

HO FAIL. CASES > Outgoing internal HO counters

4.2 Internal handover indicators per cell Outgoing internal HO - counters

Preparation Request MC655A

Any preparation failure MC655A-MC660

Attempt MC660


Success MC656

Execution

OUTGOING INTERNAL Handover

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

1.178

4.2 Internal handover indicators per cell Outgoing internal HO - indicators

SUCCESS

HO FAIL. CASES > Outgoing internal HO indicators

90

1.179

With K1205, find in the PAIB29.REC file:

1) One case of intra-cell failure with reversion2) One case of Internal handover success

l Identify the target celll Identify the serving cell (in CR for call

establishment)

3) One case of Internal handover failure with reversion

4) One case of Internal handover failure without reversion

4.2 Internal handover indicators per cell Intra-cell HO / Internal HO - exercise




4.3 External handover indicators per cell

91

1.181

4.3 External handover indicators per cell External HO - success

HO FAIL. CASES > External HO > successful case

B8

MS serving_cell BSC MSC BSC target_cell MS- MEAS_REPORT ->

------- MEAS_RESULT -------->MC645A ------ HO_REQUIRED ---------->

----------CR (HO_REQUEST) -----> MC820<--------- CC ------------------------ ---- CHANNEL_ACTIVATION ------>

<- CHANNEL_ACT_ACK-------------<----- HO_REQUEST_ACK -------- Start T9113

(HO_COMMAND) MC821<------------------------- HO_COMMAND ------------------------------------------------------ <---- HO_ACCESS -----

MC650 Start T8 <---- HO_ACCESS -----<------ HO_DETECTION--------------

<-- HO_DETECTION -------------- --- PHYSICAL_INFO -->

<--- SABM ---------------<----- ESTABLISH_INDICATION ---- ----- UA -------------->

<----------- HO_COMPLETE ----------------------------------------<--- HO_COMPLETE --------------- Stop T9113

<---- CLEAR_COMMAND ------ MC642MC646 Cause: HO_SUCCESSFUL

Release of TCH Stop T8

MC462A

MC462B

MC462C

MC463A

MC463B

MC463C

(See comments)

1.182

4.3 External handover indicators per cell External HO - failures

HO FAIL. CASES > Incoming external HO failures

Handover procedure from the target cell point of view

Ø Handover Preparation: l congestion: no RTCH available in the target cell OR no TTCH available

on the A interfaceO does not concern the outgoing side (serving cell point of view)

l BSS problem (no specific counter)

Ø Handover Execution: l radio problem: the MS fails to access the new channel


92

1.183

4.3 External handover indicators per cell Incoming external HO - RTCH congestion

HO FAIL. CASES > Incoming external HO fail: Air/Abis cong.MC541ATCH+MC81SDCCH

MS serving_cell BSC MSC BSC target_cell MS- MEAS_REPO RT ->

------- MEAS_RESULT -------->M C64 5A ------ HO _REQUIRED ------->

----------CR (HO _REQUEST) -----> M C82 0

< ----- HO _FAILURE --------------- M C54 1A( < -HO _REQ UIRED_REJECT-) Cause: no radio resource available

1.184

4.3 External handover indicators per cell Incoming external HO - TTCH congestion

HO FAIL. CASES > Incoming external HO fail: A int. cong.MC41B


------- MEAS_RESULT -------->MC645A ------ HO_REQUIRED ------->

----------CR (HO_REQUEST) -----> MC820

< ----- HO_FAILURE --------------- MC41BCause: terrestrial circuit already allocatedRequested terrestrial resource unaivalableBSS not equiopoed

( < -HO_REQUIRED_REJECT-)

93

1.185

HO FAIL. CASES > Incoming external HO fail: MS accessproblem

4.3 External handover indicators per cell Incoming external HO - radio failure


------- MEAS_RESULT -------->MC645A ---- HO_REQUIRED ------->

----------CR (HO_REQUEST) -------------------> MC820< -------- CC --------------------------------------- - CHANNEL_ACT ---------->

< --- CHA_ACT_ACK --------Start T9113

< ----- HO_REQUEST_ACK----------------------- Start T9113< -------------------------- HO_COMMAND ------------------------------------------------ HO-COMMAND) included° MC821

Start T8 X --- HO_ACCESS -----X ---- HO_ACCESS -----

----- SABM --- X----- SABM --- X

----- SABM --- X T9113 expiryMC643

Release of connection



----------CR (HO_REQUEST) -------------------> MC820< -------- CC --------------------------------------- - CHANNEL_ACT ---------->

< --- CHA_ACT_ACK --------< ----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included MC821

< -------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----

X ---- HO_ACCESS ---------- SABM -------->< --- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>----- CLEAR_COMMAND ----------------------> MC643Radio interface fail : Reversion to old channel Release of connection

1.186

HO FAIL. CASES > Incoming external HO counters

4.3 External handover indicators per cell Incoming external HO - counters

Request MC820


Attempt MC821

Radio (MS access problem) MC643BSS Pb MC821-MC642-MC643

Success MC642

Execution

Preparation

INCOMING EXTERNAL Handover

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

ATTEMPT SUCCESS

REQUEST

RATIO

Inter PLMN HO Intra PLMN HO

B8

New B8

94

1.187

4.3 External handover indicators per cell Incoming external HO - indicators

ATTEMPT

BSS PB

SUCCESS

HO FAIL. CASES > Incoming external HO indicators

B8 (See comments)

1.188

4.3 External handover indicators per cell Outgoing external HO - failures

HO FAIL. CASES > Outgoing external HO failures

Handover procedure from the serving cell point of view

Ø Handover Preparation: l congestion on the target cell (no specific counter on the serving cell)l BSS problem (no specific counter)

Ø Handover Execution: l radio problem: the MS reverts to the old channell radio problem: the MS dropsl BSS problem (no specific counter)

95

1.189

4.3 External handover indicators per cell Outgoing external HO - radio failure ROC

HO FAIL. CASES > Outgoing external HO fail: reversion old channel



----------CR (HO_REQUEST) ------------------->< -------- CC --------------------------------------- - CHANNEL_ACT ---------->

< --- CHA_ACT_ACK --------< ----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included

< -------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----MC650 X ---- HO_ACCESS -----

----- SABM -------->< --- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>MC647 ----- CLEAR_COMMAND ---------------------->

Radio interface fail : Reversion to old channel Release of connection

1.190

4.3 External handover indicators per cell Outgoing external HO - radio failure drop

HO FAIL. CASES > Outgoing external HO fail: drop



----------CR (HO_REQUEST) ------------------->< -------- CC --------------------------------------- - CHANNEL_ACT ---------->

< --- CHA_ACT_ACK --------< ----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included

< -------------------------- HO_COMMAND ------------------------------------------------Start T8 X --- HO_ACCESS -----MC650 X ---- HO_ACCESS -----

----- SABM --- X----- SABM --- X

----- SABM --- X

T8 expiry ----- CLEAR_REQUEST ->MC648 Radio interface message fail Release of connection

96

1.191

HO FAIL. CASES > Outgoing external HO counters

4.3 External handover indicators per cell Outgoing external HO - counters

Preparation Request MC645A

Any preparation failure MC645A-MC650

Attempt MC650


Success MC646

Execution

OUTGOING EXTERNAL Handover

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

ATTEMPT SUCCESS

REQUEST

RATIO

Inter PLMN HO Intra PLMN HO

B8

New B8

1.192

4.3 External handover indicators per cell Outgoing external HO - indicators

ATTEMPT

SUCCESS

HO FAIL. CASES > Outgoing external HO indicators

B8 (See comments)

97

1.193

In PAIB29.REC, extract (if available):

ü 1 incoming external HO successü 1 outgoing external HO successü 1 incoming external HO failureü 1 outgoing external HO failure

4.3 External handover indicators per cell External HO - exercise




4.4 Handover indicators per couple of cells

98

1.195

4.4 Handover indicators per couple of cells Type 180 counters

t Some handover indicators available per couple of (serving, target) cells: l permanently for all adjacencies through PM type 180

counters 3 counters for each (Serving,Target) adjacency: C400(S,T): Incoming handovers requested to cell T from cell SC401(S,T): Incoming handovers attempted to cell T from cell SC402(S,T): Incoming handovers successfully performed to cell T from cell S

both internal and external inter cell handovers are counted

both SDCCH and TCH handoversare counted

a

e

d

c

b

f

C40i(f,d)

C40i(a,b)C40i(c,b)

C40i(c,d)

1.196

4.4 Handover indicators per couple of cells Type 180 indicators

The following indicators can be computed from PM Type 180 counters in order to

t Detect the most important neighboring cells as per their traffic l Distribution of incoming handovers performed to cell T from serving cells

Sn= C402(Sx,T) / ∑ C402(Sn,T)

t Ease the diagnosis of the bad handover performance of a cell l Global efficiency of incoming handovers to cell T from cell S

HOOASUR = C402(S,T) / C400(S,T)

l Efficiency of the incoming handover preparation to cell T from cell SHOOACAR = C401(S,T) / C400(S,T)

l Efficiency of the incoming handover execution to cell T from cell SHOOAEFR = C402(S,T) / C401(S,T)

n

99

1.197

counters for each (Serving,Target x) adjacency: C720(S,Tx): Outgoing handovers attempted from

cell S to cell TxC721(S,Tx): Outgoing handovers successfully

performed from cell S to cell TxC722(S,Tx): Outgoing handovers failed from cell

S to cell Tx with Reversion Old ChannelC723(S,Tx): Outgoing handovers failed from cell

S to cell Tx with drop

these type 26 counters are available for several cells at the same time (40 cells)


t Some handover indicators are available per couple of (serving, target) cells: l on demand for all outgoing adjacencies of a serving cell

through PM type 26

Target a

Te

Serving

Tc

Tb

Tf

C72i(S,Te)

C72i(S,Tc)

B8

Modified in B8

1.198


The following indicators can be computed from PM Type 26 counters in order to:

t ease the diagnosis of the bad outgoing handover performance of acell l Efficiency of the outgoing handover execution from cell S to cell Tx

HOOXSUR = C721(S,Tx) / C720(S,Tx)l Rate of outgoing ho execution failures due to radio problems from S to Tx

with dropHOOXCDRR = C723(S,Tx) / C720(S,Tx)

l Rate of outgoing ho execution failures due to radio problems from S to Txwith Reversion Old ChannelHOOXOCR = C722(S,Tx) / C720(S,Tx)

l Rate of outgoing ho execution failures due to BSS problems from S to TxHOOXCDBR = [C720(S,Tx)-C721(S,Tx)-C722(S,Tx)-C723(S,Tx)] / C720(S,Tx)

these type 26 counters are available for several cells at once (40 cells)

B8

Modified in B8

100

1.199

counters for each (Serving,Target x) adjacency:

C730(Sx,T): Incoming handovers attempted to cell T from cell Sx

C731(Sx,T): Incoming handovers successfully performed to cell T from cell Sx

C733(S,Tx): Incoming handovers failed due to MS radio access problems to cell T from cell Sx


t Some handover indicators are available per couple of (serving, target) cells: l on demand for all incoming adjacencies of a target cell

through PM type 27

Serving a

Se

Target

Sc

Sb

Sf

C73i(Se,T)

C73i(Sc,T)

1.200


The following indicators can be computed from PM Type 27 counters in order to

t Ease the diagnosis of the bad incoming handover performance of a cell l Efficiency of the incoming handover execution to cell T from cell Sx

HOIXSUR = C731(Sx,T) / C730(Sx,T)

l Rate of incoming ho execution failures due to MS radio access problems to cell T from cell Sx

HOIXCDRR = C733(Sx,T) / C730(Sx,T)

l Rate of incoming ho execution failures due to BSS problems to cell T from cell Sx

HOIXCDBR= [C730(Sx,T)-C731(Sx,T)-C733(Sx,T)] / C730(Sx,T)

101


5 DIRECTED RETRY INDICATORS

1.202

5 Directed retry indicatorsSession presentation

t Objective: to be able to describe the counters and indicators used for monitoring the efficiency of the directed retry feature

t Program: 5.1 Directed Retry definition

102


5 DIRECTED RETRY INDICATORS

5.1 Directed Retry definition

1.204

5.1 Directed Retry definition Queuing is mandatory

When there is no TCH available in a cell for TCH normal assignment:

t Queuing: TCH request is put in a queue, waiting for a TCH to be released in this cell

t With default BSS tuning: the call establishment fails if no TCH has been freed after T11 seconds

è but an optional mechanism can be activated …

103

1.205

5.1 Directed Retry definition Normal and Forced Directed Retry

t Directed Retry (DR): When a TCH request is in queue, the BSC tries to establish the TCH connection on a neighboring cell if:

l the normal handover condition is met (Normal DR)

l specific directed retry conditions are met (Forced DR): è the MS receives a sufficient signal level from a neighboring cell

è the number of free TCHs in this neighboring cell is sufficient

1.206

5.1 Directed Retry definition Directed Retry types

DR FAIL. CASES > DR ReminderDR as an SDCCH to TCH handover can bet Internal

l between two cells of the same BSCl also called intra BSC

t Externall between two cells of different BSCsl also called inter BSC

t Incomingl as considering the target cell

t Outgoingl as considering the serving cell

t Synchronousl between 2 cellsl sharing the same clocksl collocatedl usually 2 sectors of the same

BTSè tunable at OMC-R level

t Asynchronousl not synchronous for any

reasonl no dedicated monitoring for

synchronous/asynchronous HO

104


6 RADIO MEASUREMENT STATISTICS INDICATORS

1.208

6 Radio Measurement Statistics indicatorsSession presentation

t Objective: to be able to describe the RMS indicators used for radio quality assessment of a TRX or cell and to use them in thedetection of some typical radio problems

t Program: 6.1 Radio Measurement Statistics objectives6.2 RMS implementation in the BSS6.3 RMS data6.4 Call quality statistics per TRX6.5 Radio quality statistics per TRX6.6 C/I statistics6.7 RMS indicators usage6.8 Additional information

105



6.1 Radio Measurement Statistics objectives

1.210

6.1 Radio Measurement Statistics objectivesRMS objectives

RMS objectivest Assess the quality of cell coveraget Assess the radio link quality of a TRX / a cellt Assess Carrier/Interference ratio of a TRX / a cellt Estimate of the voice quality of a TRX / a cell

In order to: èOptimize the neighborhood & frequency planningè Improve the network coverageèDetect faulty hardware components responsible for bad

QoSèHelp logical parameters fine tuning

106

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6.1 Radio Measurement Statistics objectivesRMS objectives

RMS objectives

t Provide Radio Measurement Statistics l On all the network elements (all TRXs/cells)l Permanently (RMS results available every day)

In order to èReduce the cost of Radio Network Optimization



6.2 RMS implementation in the BSS

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6.2 RMS implementation in the BSSRMS management

t RMS results are reported permanently (once a day) by the BSS as new PM counters to the OMC-R

t The RMS job is defined and activated on a per BSS basis

t RMS job parameters are managed through RMS templates

t RMS templates provide means to tune RMS parameters according to Cell Planning (cell profile, cell class)

1.214

6.2 RMS implementation in the BSSRMS configuration in the OMC-R

PM

RMS in binary filesTemplatesTemplates

RMS with OMC-R only

t Templates are defined on the OMC-Rt RMS results are retrieved once a day

from the BSCt Binary files can be exported for post-

processing

108

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6.2 RMS implementation in the BSSRMS configuration in RNO

RMS with OMC-R, NPA & RNOt Templates are defined on RNOt RMS results are retrieved once a day

from the BSCt Binary files are transferred to NPAt RMS warnings on NPAt RMS QoS reports on RNOt RMS reports used in RNO

l Checkl QoS follow-upl Diagnosisl Tuning

t The Experience matrix can be generated for network planning

t Excel export is adapted to RMS

Benefit to whole RNO

Templates

PMComputeexperience

matrix

1.216

6.2 RMS implementation in the BSSRMS data flow

RNO defines and sends RMS templates to the OMC-RThe OMC-R activates an RMS campaignin the BSSRMS counters are transferred tothe OMCRMS counters are stored in NPA RMS indicators requested by RNORMS QOS reportdisplayedRNO calculates and exports the Experience matrix to RNP

1

2

3

4

5

A9156 RNO

NPA

RNP

OMC-R

BSS

Template

1

Experience matrix

7

PM4

7

2PM

3

6

5QOS

6

QOS

109

1.217

t In all this chapter

l System parameters (user tunable or not) will always be written in BLUE BOLD FONT

l Indicators and counters will be typedin ITALIC and SHADOW EFFECT FONTITALIC and SHADOW EFFECT FONT

t The light blue font highlights important points

6.2 RMS implementation in the BSSRMS data presentation



6.3 RMS data

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t 3 main RMS statistics types

l Call quality statistics which qualify calls according to coverage/interference criteria

è based on samples corresponding to measurement results averaged over a number of SACCH multi-frames

l Radio statistics:

ü UL/DL level, UL/DL qual,

ü CFE

l C/I statistics on neighboring freq/MAFA freq

è last 2 statistics types based on samples corresponding to measurement results

6.3 RMS dataRMS data presentation

Annex 1



6.4 Call quality statistics per TRX

111




6.4.1 Generalities

1.222

6.4.1 GeneralitiesVoice Quality problem

Suspecting a Voice Quality problemt Percentage of Noisy calls

112

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6.4.1 GeneralitiesCall Quality measurements

VQ_AVERAGE = 4 SACCH

AV_RXLEV_UL_VQ = (RxlevUL1+RxlevUL2+RxlevUL3+RxlevUL4) / 4AV_RXLEV_DL_VQ = (RxlevDL1+RxlevDL2+RxlevDL3+RxlevDL4) / 4

AV_RXQUAL_UL_VQ = (RxqualUL1+RxqualUL2+RxqualUL3+RxqualUL4) / 4AV_RXQUAL_DL_VQ = (RxqualDL1+RxqualDL2+RxqualDL3+RxqualDL4) / 4

AV_RXFER_UL_VQ = (Nb of speech frames wrongly decoded (BFI=1)/ Total nb of speech frames of the CQS)

Average level, quality and FER of a Call Quality Sample

SACCH meas.begin end

CALL

480ms

CQS1 CQS2 CQS3 CQS4 CQS5 CQS6 CQS7 CQS8 CQS9 CQS10 CQS11 CQS12 CQS13 CQS14 CQS15 CQS16 CQS375

1 measurement report⇔

1 SACCH mfr

1.224

6.4.1 GeneralitiesClassification of a CQS and Noisy Call identification

quality

Level (dBm)

7

0

-110 -47VQ_RXLEV

bad quality + good levelò

interfered CQS

bad quality & levelò

bad coverage CQS

VQ_RXQUAL

CQS

How to qualify the quality of a call? By looking at the repartition of the CQS!!:

113




6.4.2 Call quality parameters

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6.4.2 Call quality parametersRMS parameters

Call quality statisticsParameters used to determine if a call is noisy (according to

RXQUAL) and of bad voice quality (according to FER)

t VQ_AVERAGE: averaging window size on measurement results to obtain Call Quality Samples (CQSs) (0 SACCH mfr to 128 Smf)

t VQ_RXLEV: radio level threshold to specify a bad coverage CQS for noisy call statistics (-110 to -65 dBm)

t VQ_RXQUAL: radio quality threshold to specify a bad quality (RXQUAL) CQS for noisy call statistics (0 to 7)

t VQ_RXQUAL_VS_RXFER: radio quality threshold to specify a bad or a good quality CQS correlated to bad or good FER measurements for noisy call statistics (0 to 7)

114

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6.4.2 Call quality parametersRMS parameters

call quality statistics

t VQ_GOOD_RXFER: Frame Erasure Rate threshold to specify a good FER CQS for noisy call statistics (0 to 20%)

t VQ_BAD_RXFER: FER threshold to specify a bad FER CQS for noisy call statistics (0 to 20%)

t VQ_INTF_THRESHOLD: Call Quality Samples threshold to characterize a call as noisy (0 to 100%)

t VQ_FER_THRESHOLD: Call Quality Samples threshold to characterize a call as “of bad or good” voice quality (0 to 100%)




6.4.3 Call quality counters

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6.4.3 Call quality countersRMS counters (1/4)

tt VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCERMS10 = Number of calls suffering from interference problem on the uplink path

tt VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCE is incremented whenever a call verifies: 100*(INTERFERED_UL_SAMPLES / NUM_UL_SAMPLES) > VQ_INTF_THRESHOLD

with INTERFERED_UL_SAMPLES = nb of times where AV_RXQUAL_UL_VQ > VQ_RXQUALand AV_RXLEV_UL_VQ>VQ_RXLEV

1.230

tt VQ_NOISY_UL_INTERFERENCEVQ_NOISY_UL_INTERFERENCERMS10 = Number of calls suffering from interference problem on the uplink path

tt VQ_NOISY_DL_INTERFERENCEVQ_NOISY_DL_INTERFERENCERMS11 = Number of calls suffering from interference problem on the downlink path

tt VQ_NOISY_UL_COVERAGEVQ_NOISY_UL_COVERAGERMS12 = Number of calls suffering from bad coverage problem on the uplink path

tt VQ_NOISY_DL_COVERAGEVQ_NOISY_DL_COVERAGERMS13 = Number of calls suffering from bad coverage problem on the downlink path


116

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tt VQ_NOISY_UL_UNDEFINEDVQ_NOISY_UL_UNDEFINEDRMS14 = Number of calls suffering from both problems of interference and bad coverage on the uplink path

è These calls are not counted in VQ_NOISY_UL_COVERAGE or VQ_NOISY_UL_INTERFERENCE

tt VQ_NOISY_DL_UNDEFINEDVQ_NOISY_DL_UNDEFINEDRMS15 = Number of calls suffering from both problems of interference and bad coverage on the downlink path

è These calls are not counted in VQ_NOISY_DL_COVERAGE or VQ_NOISY_DL_INTERFERENCE


1.232

tt VQ_NOISY_UL_BAD_FERVQ_NOISY_UL_BAD_FERRMS16 = Number of calls with bad quality measurements and with bad FER measurements on the uplink path

è Bad quality means bad RXQUAL whatever RXLEV is

tt VQ_NOISY_UL_GOOD_FERVQ_NOISY_UL_GOOD_FERRMS17 = Number of calls with bad quality measurements but with good FER measurements on the uplink path

tt VQ_ABNORMAL_BAD_FERVQ_ABNORMAL_BAD_FERRMS18 = Number of calls with fair quality measurements but with bad FER measurements on the uplink path


117



6.5 Radio quality statistics per TRX




6.5.1 Generalities

118

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6.5.1 Generalities TRX hardware problem

Suspecting a TRX hardware problem t Average Path Balance

1.236

6.5.1 Generalities Vector counter

t The real number of Measurement Results in which Path balance is in PATH BALANCE band j is equal to:l S(PATH BALANCE band j) x Max / 254 l TPR_PATH_BALANCE(j) x MAX_PATH_BALANCE / 254

RMS7a=TPR_PATH_BALANCETPR_PATH_BALANCE RMS7b=MAX_PATH_BALANCEMAX_PATH_BALANCE

119

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6.5.1 Generalities Cell coverage problem

Suspecting a cell coverage problem

t Distribution of samples per RxQual value and RxLev band

t Distribution of samples per RxLev band

1.238

6.5.1 Generalities Matrix counter

TPR_RXQUAL_UL_RXLEV_ULTPR_RXQUAL_UL_RXLEV_UL TMR_RXQUAL_UL_RXLEV_ULTMR_RXQUAL_UL_RXLEV_UL

120




6.5.2 Radio quality parameters

1.240

6.5.2 Radio quality parametersRMS parameters (1/3)

Radio quality statisticsparameters used to define intervals for RXLEV, Path Balance,

Radio Link Counter and Consecutive Frame Erasure statistics

t MEAS_STAT_LEV1 to MEAS_STAT_LEV9: 9 thresholds on the received radio level value defining 10 RXLEV bandsl -110 ≤ MEAS_STAT_LEV(i+1) ≤ MEAS_STAT_LEV(i) < -47 dBm

t MEAS_STAT_PATH_BAL1 to MEAS_STAT_PATH_BAL9: 9 thresholds on the radio signal propagation loss difference between UL and DL defining 10 Path Balance bandsl -110 < MEAS_STAT_PATH_BAL(i) ≤ MEAS_STAT_PATH_BAL(i+1) ≤ +110 dB

121

1.241


Radio quality statistics

t TA_STAT: threshold on the timing advance value defining a priori the range of the cell (0 to 64 bits)

t MEAS_STAT_S1 to MEAS_STAT_S9: 9 thresholds on the BTS Radio Link Counter S value defining 10 S bands l 0 < MEAS_STAT_S(i) ≤ MEAS_STAT_S(i+1) ≤ 128 SACCH mfrl S: counter managed by the BTS on a per call basisl S = RADIOLINK_TIMEOUT_BS if good radio conditionsl S decremented if bad radio conditionsl The BSS triggers a call drop when S = 0

1.242



t MEAS_STAT_BFI1 to MEAS_STAT_BFI9: 9 thresholds on the number of consecutive speech frames with BFI set to 1 defining 10 BFI bands l 0 < MEAS_STAT_BFI(i) ≤ MEAS_STAT_BFI(i+1) ≤ 25 speech frame

t The BTS decodes 24 speech frames (sf) from 1 uplink SACCH multi-frame:

and 1 SACCH frame (or block)

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH mfrTDMA: 4,616ms

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

SACCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

TCH

Sf 1 Sf 2 Sf 3 Sf 4 Sf 5 Sf 6 Sf 7 Sf 8 Sf 9 Sf 10 Sf 11 Sf 12 Sf 13 Sf 14 Sf 15 Sf 16 Sf 17 Sf 18 Sf 19 Sf 20 Sf 21 Sf 22 Sf 23 Sf 24

122




6.5.3 Radio quality counters

1.244

6.5.3 Radio quality counters RMS counters (1/7)

Radio quality statistics tt TPR_RXQUAL_UL_RXLEV_ULTPR_RXQUAL_UL_RXLEV_UL: matrix of 8x10 elements

UL(RXQUAL i, RXLEV band j), each element is made up of: l Samplesij: norm of number of measurement result samples

in which UL RxQual is equal to i and UL RxLev is reported in RXLEV band j

l MS PWR levelij: average value of MS power (in dBm) from pwr levels reported in these samples

l Timing Advanceij: average value of TAs reported in these samples

tt TMR_RXQUAL_UL_RXLEV_ULTMR_RXQUAL_UL_RXLEV_UL: vector of 10 elements ULRXQUAL(RXLEV band j), each element is made up of: l the maximum value of the 8 real numbers of samples in

which UL RxQual is equal to i (i=0 to 7) and UL RxLev is reported in RXLEV band j

123

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Radio quality statistics tt TPR_RXQUAL_DL_RXLEV_DLTPR_RXQUAL_DL_RXLEV_DL: matrix of 8x10 elements

DL(RXQUAL i, RXLEV band j), each element is made up of: l Samplesij: norm of number of measurement result samples

in which DL RxQual is equal to i and DL RxLev is reported in RXLEV band j

l BS PWR levelij: average value of BS power (in dBm) from pwr levels reported in these samples

l Timing Advanceij: average value of TAs reported in these samples

tt TMR_RXQUAL_DL_RXLEV_DLTMR_RXQUAL_DL_RXLEV_DL: vector of 10 elements DLRXQUAL(RXLEV band j), each element is made up of: l the maximum value of the 8 real numbers of samples in

which DL RxQual is equal to i (i=0 to 7) and DL RxLev is reported in RXLEV band j

1.246



tt TPR_PATH_BALANCETPR_PATH_BALANCE: vector of 10 elements UL/DL(PATH BALANCE band j), each element is made up of: l the norm of number of measurement result samples for which

the computed Path Balance is in PATH BALANCE band j

tt MAX_PATH_BALANCEMAX_PATH_BALANCE: l the maximum value of the 10 real numbers of samples for

which the computed Path Balance is in PATH BALANCE band j (j=1 to 10)

124

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tt TPR_RADIO_LINKTPR_RADIO_LINK: vector of 10 elements UL(S band j), each element is made up of: l the norm of number of measurement result samples for which

the Uplink Radio Link Counter is in S band j

tt MAX_RADIO_LINKMAX_RADIO_LINK: l the maximum value of the 10 real numbers of samples for

which the Uplink Radio Link Counter is in S band j (j=1 to 10)

1.248



tt TPR_BFI_RXLEV_ULTPR_BFI_RXLEV_UL: matrix of 10x10 elements UL(BFI i, RXLEV band j), each element is made up of: l the norm of number of SACCH multi-frames in which the

number of consecutive speech frames with BFIs set to 1 is in BFI band i and UL RxLev reported in the corresponding measurement results is in RXLEV band j

tt TMR_BFI_RXLEV_ULTMR_BFI_RXLEV_UL: vector of 10 elements ULBFI(RXLEV band j), each element is made up of: l the maximum value of the 10 real numbers of SACCH multi-

frames in which the number of consecutive speech frames with BFIs set to 1 is in BFI band i (i=0 to 9) and UL RxLevreported in the corresponding measurement results is in RXLEV band j

125

1.249



t The BTS increments the BFI (or CFE) counter as soon as consecutive speech frames cannot be decodedl isolated speech frames with BFIs set to 1 are not countedl sequences of not decoded speech frames are cumulated

SACCH mfr

CFE0 0 0 0 0 0 0 0 1 2 3 3 3 3 4 4 4 5 6 6 6 6 6 7 7

BFI

Sf 1 Sf 2 Sf 3 Sf 4 Sf 5 Sf 6 Sf 7 Sf 8 Sf 9 Sf 10 Sf 11 Sf 12 Sf 13 Sf 14 Sf 15 Sf 16 Sf 17 Sf 18 Sf 19 Sf 20 Sf 21 Sf 22 Sf 23 Sf 24 SACCH f.

0 0 0 1 0 0 0 1 1 1 1 0 0 1 1 0 1 1 1 0 1 0 1 1 0

RxLev UL10 11 9 12 12 11 11 10 3 2 0 8 9 5 3 7 2 1 2 7 3 8 2 3 5

Av_RxLev_UL= - 110 + INT[(10+11+9+12+12+11+11+10+3+2+0+8+9+5+3+7+2+1+2+7+3+8+2+3+5)/25]= -104 dBm

1.250



tt PERC_TA_GT_TA_STATPERC_TA_GT_TA_STAT: l percentage of measurement results reported with a Timing

Advance value > TA_STAT parameter

tt MAX_TAMAX_TA: l maximum value of Timing Advance among all TA values

reported in the measurement results used for RMS

126



6.6 C/I statistics



6.6 C/I statistics

6.6.1 C/I Generalities

127

1.253

6.6.1 C/I Generalities Storage and computation methods

t In order to provide an efficient storage, the "vector method" already seen for previous RMS statistics will be used for C/I counters

t C/I expressed in logarithmic scale (dB)l (C/I)dB = CdBm - IdBm = 10 log10(CmW) - 10 log10(ImW)

= 10 log10(C/I)mW



6.6 C/I statistics

6.6.2 C/I Parameters

128

1.255

6.6.2 C/I parameters RMS parameters

C/I statistics parameters defining intervals for C/I statistics

t MEAS_STAT_C_I1 to MEAS_STAT_C_I9: 9 thresholds on the Carrier/Interference ratio defining 10 C/I bands l -63 < MEAS_STAT_C_I(i) ≤ MEAS_STAT_C_I(i+1) ≤ +63 dB

t EN_BALANCED_CI: boolean indicating if the C/I value reported by the BTS is balanced or not

t NEIGB_CELL_ID: (BCCH,BSIC) of the neighboring cell for which the C/I statistics per neighboring cell are reported

t Frequency ARFCN: ARFCN of the frequency for which the C/I statistics per MAFA frequency are reported Annex 2



6.6 C/I statistics

6.6.3 C/I Counters

129

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6.6.3 C/I counters RMS counters

C/I statistics per neighboring cell

tt TPR_CINTPR_CIN: vector of 10 elements C/In(C/I band j), each element is made up of: l the norm of number of measurement result samples for which

the computed Carrier/Interference ratio is in C/I band jtt MR_CINMR_CIN: l maximum value of the 10 real numbers of samples for which

the computed Carrier/Interference ratio is in C/I band j (j=1 to10)

TPR_CINTPR_CIN and MR_CINMR_CIN counters are provided for up to 42 neighboring cells

1.258

6.6.3 C/I counters RMS counters

C/I statistics per MAFA frequency

tt TPR_CIFTPR_CIF: vector of 10 elements C/If(C/I band j), each element is made up of: l the norm of number of Extended Measurement Results

samples for which the computed Carrier/Interference ratio is in C/I band j

tt MR_CIFMR_CIF: l maximum value of the 10 real numbers of samples for which

the computed Carrier/Interference ratio is in C/I band j (j=1 to10)

TPR_CIFTPR_CIF and MR_CIFMR_CIF counters are provided for up to 21 frequencies (serving cell BCCH + 20 MAFA frequencies)

130



6.7 RMS indicators usage

1.260

6.7 RMS indicators usage Voice quality problem

Suspecting a Voice Quality problem RMS indicatorst Percentage of Noisy calls

t FER is more reliable than RXQUAL to assess VQt Noisy calls indicators can also be computed from FER

measurementsl Noisy calls with bad or good FERl Calls not detected as noisy but with bad FER

Voice Quality indicators are based on calls

Noisy calls are associated with a cause of

bad coverage, interference or with an undefined cause

131

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6.7 RMS indicators usage Cell coverage problem

Suspecting a cell coverage problem

t Distribution of samples per RxQual value and RxLev band

t Distribution of samples per RxLev band

Not acceptablecoverage limit: Too low level Too bad quality

1.262

6.7 RMS indicators usage Cell coverage problem

Suspecting a cell coverage problem RMS indicatorst Average TA values per RxQual value and RxLev band

Not acceptablecoverage limit: Too low level Too bad quality

Acceptable coverage limit: Sufficient level and good quality

% of TA value over TA threshold has also to be considered

132

1.263

6.7 RMS indicators usage RMS Exercise 1

ü Give the list of the RMS counters and parameters used in the 3 previous slides


1.264

6.7 RMS indicators usage RMS exercise 2

üWhat does this graph represent?ü Interpret this graph


133

1.265

6.7 RMS indicators usage Cell interference problem

Suspecting a cell interference problemt Number of samples per RxQual value and RxLev band

Average DL RxQuality = 0.34

RMS results show no problemof radio link quality in this cell

Average RxQual value per RxLev band has also to be considered

1.266


Average RxQual value per RxLev band has also to be considered

Average DL RxQuality = 2.81


ü Interpret this graph

134

1.267


Time allowed: 15 minutes ü Interpret this graph

1.268


ü Interpret this graph


135

1.269


ü Compute the RMS counters and indicators in the file




6.8 Additional information

136

1.271

6.8 Additional information RMS counters (1/3)

Counters used for: t post-processing the RMS results provided per TRX

l TOT_SEIZ_TCH: number of TCH channels successfully seized by the MS

l TOT_MEAS: number of Measurement Results used for RMSl TOT_MEAS_L1INFO_NOL3INFO: number of Measurement Results

used for RMS statistics for which Layer 1 info is present but Layer 3 is missing

l TOT_MEAS_DTX_UL: number of Measurement Results used for RMS statistics for which DTX UL was used in the corresponding SACCH mfr

l TOT_MEAS_DTX_DL: number of Measurement Results used for RMS statistics for which DTX DL was used in the corresponding SACCH mfr

l TOT_EMR: number of Extended Measurement Results used for RMS statistics

1.272


Counters used for: t interpreting the RMS results provided per TRX

l TRE_BAND: frequency band of the TRX l BS_TX_PWRMAX: effective maximum output power of the BTS on any

channel of the TRX as an offset from the maximum absolute outputpower (in dB)

l MS_TX_PWRMAX: effective maximum output power of the MS using any channel of the TRX (in dBm)

l IND_TRE_OVERLOAD: boolean indicating if the TRE handling the TRX function has experienced a data loss due to a processor overload during the RMS campaign

l IND_RMS_RESTARTED: boolean indicating if the RMS job has been restarted on the concerned TRE during the RMS campaign due to a modification of the RMS parameter values or a TRE reset

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Counters used for: t interpreting the C/I RMS results provided per TRX

l IND_CI_PARTIAL_OBSERVATION: made up of 2 booleans indicating that:

è C/In computation has been restarted due to the modification of the list of neighboring cells during the RMS campaign

è C/If computation has been restarted due to the modification of the list of MAFA frequencies during the RMS campaign

l IND_CI_OVERFLOW: boolean indicating that the upper limit of 42 C/I sets of counters has been exceeded (each new reported neighboring cell (BCCH, BSIC) has not been taken into account in RMS statistics)


7 TRAFFIC INDICATORS

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7 Traffic indicatorsSession presentation

t Objective: to be able to describe BSS traffic indicators used for radio resource dimensioning

t Program: 7.1 Call mix definition7.2 Basis of traffic theory7.3 TCH resource allocation indicators7.4 Resource occupancy indicators7.5 Traffic model indicators7.6 Preemption indicators



7.1 Call mix definition

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7.1 Call mix definitionGSM transactions

t In a GSM Network, there are a lot of different transactions : l location update: periodic, new updating, ~imsi_attach,

~imsi_detachl Hand Over (intra-cell, internal, external, etc.)l SMS (Short Message Service, originating or terminating)l SS (Supplementary Service)l Pagingl and also Originating and Terminating calls, etc.l and so on (data, SMS-CB, etc.)

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7.1 Call mix definitionGSM transactions

t One can quantify the number of each transaction per hour

t For example, for one cell, one can measure: l 900 calls (600 TCs, 300 OCs)l 3600 LUs (any type)l 1350 HOs (900 internal, 450 external)l 100 SMSsl 5 SSsl 6000 pagingsWith the following characteristicsl mean call duration on TCH: 50 secondsl mean SDCCH duration: 3.2 seconds

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7.1 Call mix definitionExample

t Set of such measurements is called "call mix"l sometimes improperly called "traffic model"

t Usually presented in the following way: l Calls /hour : 900 (2/3 TC)l LU/call : 4l HO/Call : 1.5 (2/3 internal, 1/3 external)l SMS/Call : 11 %l SS/call : 5 %l Paging/hour : 6000l mean call duration on TCH : 90 secondsl mean SDCCH duration : 4.2 seconds

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7.1 Call mix definitionVariation

t A call mix is varying a lot: l from a cell to anotherèTCH traffic (induced by subscribers)è number of LU/call and HO/call (induced by network

design)l from one hour to anotherè by default: busy hour

l from one year to anotherèmodification of traffic intensity and distribution

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7.1 Call mix definitionUsage

t Interests of call mix: Input data for dimensioningl Cell and BSC resources dimensioningèRTCH, SDCCH, TTCH, BTS, BSC and MSC CPU

processorl Some examples of "risky" call mix è too many LU/Calls: SDCCH congestion, TCU load,

MSC overloadè too many HO/calls: speech quality, call drop, DTC loadè too many calls: TCH congestionè too many pagings: DTC processor load, PCH

congestion

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7.1 Call mix definitionAdvises

t Some advises

l LU/CALL: 1 is "good", 2 is "bad", 4 and more can be dangerousè beware of the Network or BSC averages which can hide

critical cellsl HO/Call: less critical (1 is good)è 2 or 3 is not a direct problem, but the trend has to be

monitoredl Call: to be checked with an Erlang table (seen in next

session)

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7.1 Call mix definitionExercise

Training exercise

t Compute the call mix of a cell according the following informationl 256 call/hourl 1300 LU/hourl 450 HO/hour

t Is it complete? t What are the risks of such a call mix?



7.2 Basis of traffic theory

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7.2 Basis of traffic theory Erlang definition

t ERLANG: unit used to quantify traffic (intensity)t T = (resource usage duration) / (total observation duration)

[ERLANG]t Example: l For 1 TCH, observed during 1 hourl one can observe 2 calls: 1 of 80 seconds and 1 of 100

seconds

è T = (80+100)/3600 = 0.05 ERLANG

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7.2 Basis of traffic theory Erlang from call mix

CALL MIX => ERLANGt Call mix example: l 350 call/hourl 3 LU/calll TCH mean call duration: 85 secondsl SDCCH mean duration: 4.5 seconds

l Computation of Carried Erlang èTCH = (350*85)/3600: 8.26 ERLANGSèSDCCH = [ (350+350*3) * 4.5 ] / 3600 = 1.75 Erlang

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7.2 Basis of traffic theory Erlang B law

t In a Telecom system, the call arrival frequency is ruled by the POISSON law

t Erlang B law: relationship between: l offered trafficl number of resourcesl blocking rate

call/second

0

1

2

3

4

5

6

7

8

9

10

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97

call/second

0

1

2

3

4

5

6

7

8

9

10

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97

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t The call request arrival rate (and leaving) is not stablel number of resources = average number of requests * mean durationl is sometimes not sufficient => probability of blocking

t => Erlang B lawl Pblock: blocking probabilityl N: number of resourcesl E: offered traffic [Erlang]

t Good approximation when the blocking rateis low (< 5 %)

7.2 Basis of traffic theory Erlang B law

Telecom system

Offered Carried

Rejected

P b lo c k N

k

N

k

k

N

EE

=

=∑!

!0

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7.2 Basis of traffic theory Erlang B formulae

t There are two different ways to use this law

l Using Abacus

l Using SW (here Excel)èPblock = f (T, Nc)èOffered = f (Nc, Pblock)èChannels = f (T, Pblock)

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7.2 Basis of traffic theory Erlang B abacus

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t Example: 1 cell with 8 TRXs, with 60 TCH channels

l Maximum blocking rate: 2 %

èErlang law: 50 Offered Erlang

è 83 % of TCH resources used to reach 2% of blocking

7.2 Basis of traffic theory Erlang B example

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t But be careful, the Erlang B law is not linear:

l In B4, we use for example a combined BCCH with a micro BTS.è 4 SDCCHs, Pblock = 2% => T = 1.1 Eè 25% resources used to reach 2% blocking

l In B5, if we decide to provide SMSCB (Cell Broadcast information), 1 SDCCH stolen for CBCHè 3 SDCCH, Pblock = 2% => T = 0.6 Eè 25 % resources less => 50 % Traffic less!!

7.2 Basis of traffic theory Non linearity of Erlang B

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t Given an Offered traffic, compute the number of TRXs (and SDCCH) needed to carry it => What is the accepted blocking rate?

t default blocking ratel RTCH: 2 %l SDCCH: 0.5 %l (for BSC TTCH: 0.1%)

7.2 Basis of traffic theory Cell dimensioning

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t Cell dimensioning from call mix (bid, architecture)

l to handle an offered traffic of 12 Erlangs (RTCH), compute the number of channels, then the number of TRXs

èChannels (12;2%) = 19

l example: 3 TRXs, 21 TCHs, 1 BCCH, 2 SDCCHs/8

7.2 Basis of traffic theory Dimensioning "a priori"

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t Cell dimensioning from measurement (re-planning)

l one is measuring a traffic of 15 Erlangs, with a blocking rate of 10 %

l how to dimension the cell?

èOffered traffic = 15 / (1-10%) = 16.7 Erlangs!!!!èChannels (16.7;2%) -> 25 TCHs -> 4 TRXs needed

7.2 Basis of traffic theory Dimensioning "a posteriori"

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t Forecast traffic

l traffic forecasting must be computed according to the offered trafficMnot directly on the measured traffic

l In order to plan the necessary actions soon enough, one must compute regularly the date when the traffic of a cell will become critical

t Critical trafficl critical traffic: when the offered traffic will induce 2% of

blocking l traffic capacity of a cell = critical traffic of this cell

7.2 Basis of traffic theory Forecast / Critical traffic

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7.2 Basis of traffic theory Exercise

t Training exercise: complete the form to get less than 2% of blocking

cell call mix info Erlang TCHO ffered traffic

traffic forecast proposed config

12, 743 450 call/ hourmean TCH call duration : 80secblocking rate TCH : 0 .8%

10,08 Erlang TCH 30 % offered trafficincrease

13,1 Erlang TCH - > 20 TCH3 TRX

12,675 330 call/ hourmean TCH call duration 129secblocking rate 4%

30 % offered trafficincrease

12,865 600 call/ hourmean TCH call duration 96secblocking rate 8 %

30 % offered trafficincrease



7.3 TCH resource allocation indicators

B8

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7.3 TCH resource allocation indicators Radio Allocation and Management

t Radio resource allocation and management (RAM) aims at: l Managing pools of TCH radio resources by: è defining TCH radio timeslots as a function of the cell

radio configuration from the operatorè sorting these TCH TS according to their radio

capabilities (FR or DR, frequency band (G1 or GSM/DCS))

l Allocating dedicated TCH radio resources by: è selecting the TCH pool in which the TCH should be

chosen according to:ü the requested channel rate (FR or HR)ü the radio capability of the mobileü the TRE DR capability and the TRE band

è selecting the best TCH resource among the available TCH channels of this pool according to several criteria

B8

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7.3 TCH resource allocation indicators MS access

t MS access types distribution (NA only)B8: Accessibility in type 110

l TCH requests from FR only MSTCNARQMN= MC701A

l TCH requests from DR MSTCNARQBN= MC701B

l TCH requests from DR+EFR MSTCNARQTN= MC701C

l TCH requests from AMR MSTCNA3RQTN= MC701D

l TCH requests from Data callsTCNARQDN= MC701E

B8

Modified in B8

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7.3 TCH resource allocation indicators Speech coding version

t Speech coding Version capabilities distribution (NA only)B8: Accessibility in type 110

l TCH allocations with FR SV1TCNACAFN= MC702A

l TCH allocations with HR SV1 TCNACAHN= MC702B

l TCH allocations with FR SV2 (EFR) TCNACAEN= MC702C

l TCH allocations with FR SV3 (AMR FR) TCNA3CAFN= MC704A

l TCH allocations with HR SV3 (AMR HR) TCNA3CAHN= MC704B

l TCH allocations for data call TCNACADN= MC705

B8

Modified in B8

These 2 counters are

new in B8.

In B7, only one

without details: MC704

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7.3 TCH resource allocation indicators Distributions

t FR/HR calls distribution (NA+HO) l FR TCH allocation ratio

TCAHCAFO = MC370A / (MC370A+MC370B)

l HR TCH allocation ratioTCAHCAHO = MC370B / (MC370A+MC370B)

t NA/HO distribution l Normal Assignment TCH allocation ratio

TCNACAO = MC703 / (MC703 + [MC15A+MC15B])

l Handover TCH allocation ratio TCHOCAO = [MC15A+MC15B] / (MC703 + [MC15A+MC15B])

t TCH allocation distribution per TRXl Number of TCH allocations for Normal Assignment

TCNACAN = MC703

B8

152



7.4 Resource occupancy indicators

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7.4 Resource occupancy indicatorsTCH resource

t TCH resource occupancyl TCH traffic in Erlang

TCTRE= (MC380A+MC380B) / 3600

l TCH mean holding time (TCH average duration)TCTRMHT= (MC380A+MC380B) / (MC370A+MC370B)

l FR TCH traffic in Erlang TCTRE= MC380A / 3600

l FR TCH mean holding timeTCTRFMHT= MC380A/ MC370A

l HR TCH traffic in Erlang TCTRE= MC380B / 3600

l HR TCH mean holding timeTCTRHMHT= MC380B/ MC370B

B8 (See comments)

New B8

A split of the counters 380a and b

provides information about multiband

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7.4 Resource occupancy indicatorsSDCCH / ACH resource

t SDCCH resource occupancyl SDCCH traffic in Erlang

SDTRE= MC400 / 3600

l SDCCH mean holding time (SDCCH average duration)SDTRMHT= MC400 / MC390

t ACH resource occupancyl ACH traffic in Erlang

C750 / 3600

l ACH mean holding time (ACH average duration) QSTRN =C750 / C751



7.5 Traffic model indicators

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7.5 Traffic model indicatorsSDCCH establishment

t SDCCH establishment cause distributionl Ratio of MT calls

TMMTO= MC01 / SDCCH ASSIGN SUCCESS

l Ratio of MO normal and emergency callsTMMTO= MC02H / SDCCH ASSIGN SUCCESS

l Ratio of LU normal (resp. follow-on)TMMOLUR = MC02A (resp. MC02D) / SDCCH ASSIGN SUCCESS

l Ratio of IMSI detachTMMOLUDR= MC02G / SDCCH ASSIGN SUCCESS

l Ratio of Short Message ServiceTMMOSMSR= MC02B / SDCCH ASSIGN SUCCESS

l Ratio of Supplementary ServiceTMMOSSR= MC02C / SDCCH ASSIGN SUCCESS

l Ratio of Call re-establishmentTMMOCRR= MC02E / SDCCH ASSIGN SUCCESS

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7.5 Traffic model indicatorsMobiles penetration

t E-GSM mobiles penetrationl Ratio of E-GSM MS access over all MS accesses (except LU)

TMMSEGR = MC706 / ([MC01+MC02]-[MC02A+MC02D+MC02G])

t Multiband mobiles penetrationl Ratio of Multiband MS access over all MS accesses (except LU)

TMMSMBR = MC850 / ([MC01+MC02]-[MC02A+MC02D+MC02G])

t AMR mobiles penetrationl Ratio of TCH allocation for AMR MS over all TCH allocations

TCTR3CATTO = MC704A+ MC704B / MC703

t TFO calls ratiol Ratio of successful TFO establishment over all TCH allocations

QSTRCCTR = MC170 / MC703

t Handover per Calll Number of Handovers (intra cell,internal,external) per Normal Assignment

TMHOCO = (MC717A+MC717B) / MC718

B8

New B8

(See comments)

155



7.6 Preemption indicators

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7.6 Preemption indicatorsPreemption principle

t Preemption attributes (in Assignment or HO Request): l pci : preemption capability indication

è indicates if the call can preempt another call (pci=1) or not

l pvi : preemption vulnerability indicationè indicates if the call is preemptable (pvi=1) or not

l priority level: 1=highest priority / 14=lowest priority

t Preemption rules:l A TCH request with pci=1 and priority level=p1 will preempt an on-going

call with pvi=1 and priority level=p2, p2 lower than p1 (whatever pcivalue)

l the on-going call with the lowest priority level value shall be elected first and if several calls have the same lowest p2 value, one of them with pcibit set to 0 is preferred

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7.6 Preemption indicatorsPreemption counters

t MC921A = Number of TCH Requests with the capability to preempt another call with lower priority (pci=1)

t MC921B = Number of preemption capable TCH Requests (pci=1) served with TCH resource (with or without using the preemption feature).

t MC921C = Number of preempted callst MC921D = Number of preemption capable TCH Request (pci=1)

successfully served in a neighboring cell with the help of the directed retry procedure

t MC921E = Number of preemptable calls successfully established (pvi=1)

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7.6 Preemption indicators

t Preemption capable TCH Request rejection ratel TCPPFLCR = (MC921A-MC921B-MC921D) / MC921A

t Ratio of preemption capable TCH Request which led to a successful Directed Retryl TCPPDSUCR = MC921D / MC921A

t Ratio of preemptable calls established over all callsl TCPPSUVO = MC921E / (MC718+MC717A+MC717B)

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Thank you for answeringthe self-assessment

of the objectives sheet

Introduction to QoS and Traffic Load monitoring / B8Evaluation

t Objective: to be able to interpret:

ü Global indicators, in order to assess the general quality of the network

ü Detailed indicators, in order to detect / identify / locate the main malfunctions

ü Handover indicators, in order to quantify the efficiency and the reason for HO

ü Directed retry indicators, in order to quantify the efficiency of a directed retry

ü Indicators provided by the new RMS feature to ease radio optimization and fault detection

ü Traffic indicators, in order to detect/predict overload and compute adequate cell dimensioning as well as to understand how RTCH resources are used in the network

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Radio Measurement Reporting

ANNEX 1


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t Radio measurement mechanismsl MS connected (TCH or SDCCH)l The serving cell gives to the MS the list of the neighboring

cells to listenl Every SACCH, the MS reports to the serving cell:

measurement report messageè Received level of 6 best cells (which can change)è DL level and quality of serving cell


Meast

Report

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t Radio measurement mechanismsl For each MS connected to the BTS (TCH or SDCCH)


BSC

DL measurements UL+DL measurements

è The UL received level and quality are measured every SACCH

è The Timing advance (TA) is computed

è The UL information is gathered into a measurement report

è this is the message result sent by the BTS to the BSC

Meast

Report

Meast

Result

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t Measurement Result message


L1 Info

L3 Info

MeasurementReportFrom the MS

Back

1.318

Extended Measurement Reporting

ANNEX 2

Extended Measurement Reporting(MAFA)

160

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t The Extended Measurement Reporting is a feature allowing the BSS to request an MS to measure and report up to 21 frequencies of the band that are not included in its BA list

t Such phase 2+ mobiles must support the optional MAFA feature (Mobile Assisted Frequency Allocation)

1.320





< --------------------------------------------------------CHANNEL ACTIVATION (TCH)

(EMO included)-------------------------------------------------------- >CHANNEL ACTIVATION ACKNOWLEDGE

.

.TCH establishment.

--------TCH---------> .ASSIGNT COMPLETE ------------------------------------------------------- >

ASSIGNMENT COMPLETE ----------------------------------- ><------SACCH-------- ASSIGNMENT COMPLETE

--------SACCH------><------SACCH--------

--------SACCH------><-------SACCH--------

EMO(MAFA freq. List)

--------SACCH------>EMR

(MAFA freq. RxLev)<------SACCH--------

--------SACCH------>

t Extended Measurement Reporting mechanisms


l The Extended Measurement Order includes the MAFA frequencies the MS is asked to measure

l EMO sent once to the MS on SACCH after TCH seizure

l Extended Measurement Results include the average signal level measured on each MAFA frequency over one SACCH mf duration

l EMR received once per call on SACCH

Back

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ANNEX 3

Directed Retry Indicators

GSM BSS Protocol Stacks

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DR FAIL. CASES > internal DR > success case

Internal directed retry indicators Internal DR - success

The same internal DR procedure leads to an incrementation of two sets of counters: incoming DR counters for the target cell: MC153, MC151, etc.outgoing DR counters for the serving cell: MC144E, MC142E, etc.

MCx counters belong to Standard Type 110 reported permanentlyCx counters belong to Detailed Type 29 reported on demand in B7.

Becomes a Standard type in B8.

MS serving cell target cell BSC MSCTCH ASSIGNMENT PHASE (OC or TC)

< -----------------------ASSIGNMENT

REQUESTNo free TCH

TCH request queuedQueuing allowed

Start T11 ----------------------- >QUEUING_INDIC.

MC13A

IDR condition met MC153, MC144e,

CHANNEL ACTIV. (TCH)<---------------------------------- MC15A

CHAN ACTIV ACK---------------------------------->

HO CMD HANDOVER COMMAND<----------------------

(SDCCH)<------------------------------------------------------------------------ start T3103

C154, MC607start T3124 C145A+C145C

HANDOVER ACCESS------------------------(TCH)---------------------------->-------------------------------------------------------------> HO DETECTION

PHYSICAL INFORMATION ----------------------------------><------------------------------------------------------------- start T3105stop T3124start T200------------------------ SABM --------------------------> stop T3105<-------------------------- UA ----------------------------- ESTABLISH INDICATIONstop T200 ---------------------------------->

HANDOVER COMPLETE HO CMP stop T3103-------------------------------------------------------------> ----------------------------------> ASSIGNMENT

COMPLETE------------------------>

Release of old SDCCH MC151,MC717A,MC142e

B8 (see comments)

Modified inB8

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DR FAIL. CASES > Incoming internal DR failures:

Directed Retry procedure from the target cell point of view

Ø DR Preparation: l congestion: no RTCH available in the target cell

O does not concern the outgoing side (serving cell point of view)l BSS problem (no specific counter)

Ø DR Execution: l radio problem: the MS fails to access the new channel


Internal directed retry indicators Incoming internal DR - failures

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DR FAIL. CASES > Incoming internal DR fail: congestionMC555=C155

Internal directed retry indicators Incoming internal DR - congestion

MS serving cell target cell BSC MSCTCH ASSIGNMENT PHASE (OC or TC)

< ----------------------------------------------------ASSIGNMENT REQUEST

No free TCHIn serving cell

Queuing allowed

Start T11 --------------------------------------------------- >QUEUING_INDIC.

MC13A

IDR condition met MC153, MC144e,MC607

No free TCHIn target cell

MC555

B8 (see comments)

type 29 becomes

a standard type:

Available in PMC

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DR FAIL. CASES > Incoming internal DR fail: MS access problem

Internal directed retry indicators Incoming internal DR - radio failure


-----------------------> MEASUREMENT RESULT------------------------------------------------------------------------>

CHANNEL ACT IVATION<----------------------------------

CHANNEL ACTIV ACK---------------------------------->


C154SABM

-----------x T3103 expiry C152



HANDOVER ACCESS C154------------------------------------------------------------->-------------------------------------------------------------> HO DETECTION



UA ----------------------------------><------------------------------------------------------------- stop T3105



UA ------------------------------------------------------------------------><-----------------------

HO FAILURE HANDOVER FAILURE-----------------------> ------------------------------------------------------------------------> C152


B8 (see comments)

Modified inB8 Becomes a standard type

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DR FAIL. CASES > Incoming internal DR counters

Internal directed retry indicators Incoming internal DR - counters

Request MC153, C153

Congestion MC555, C155BSS Pb C153-C154-C155

Attempt C154

Radio (MS access problem) C152BSS Pb C154-C151-C152

Success MC151, C151

Execution

Preparation

INCOMING INTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT

MS ACCESS PB

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

B8 (see comments)

Modified inB8

Type 29 counters becomes a standard (PMC)

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Internal directed retry indicators Incoming internal DR - indicators

DR FAIL. CASES > Incoming internal DR indicatorst see comments

B8 (see comments)

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DR FAIL. CASES > Outgoing internal DR failures

Directed Retry procedure from the serving cell point of view

Ø DR Preparation: l congestion on the target cell (no specific counter on the serving cell)l BSS problem (no specific counter)

Ø DR Execution: l radio problem: the MS reverts to the old channell radio problem: the MS dropsl BSS problem (no specific counter)

Internal directed retry indicators Outgoing internal DR - failures

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DR FAIL. CASES > Outgoing internal DR fail: reversionold channel

C144A, C143A: Forced DR

C144C,C143E: Normal DR

Internal directed retry indicators Outgoing internal DR - radio failure ROC


HO CMD HANDOVER COMMAND<-------SDCCH----- <------------------------------------------------------------------------ start T3103

HANDOVER ACCESS MC144E----------------------TCH--------------------------------> C144A or C144C-------------------------------------------------------------> HO DETECTION



UA ----------------------------------><------------------------------------------------------------- stop T3105



UA ------------------------------------------------------------------------><-----------------------

HO FAILURE HANDOVER FAILURE-----------------------> ------------------------------------------------------------------------> C143A or C143E


B8 (see comments)

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DR FAIL. CASES > Outgoing internal DR fail: drop

M S serving ce ll targe t cell BSC M SC

H O C M D H AN DO VE R C O M M AN D<----------------------- <------------------------------------------------------------------------ start T3103

M C 144ES ABM C144A or C144C

----------x

T3103 exp iryC143B or C 143F------------------------>

ASSIGN M EN TFAILU RE

“R ad io in te rfacem essage failu re ”

R elease of S DC CH and TC H

Internal directed retry indicators Outgoing internal DR - radio failure drop

C144A,C143B: Forced DR

C144C,C143F: Normal DR

(See comments)B8

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DR FAIL. CASES > Outgoing internal DR counters

Internal directed retry indicators Outgoing internal DR - counters

Preparation Request MC144E, C144A+C144C

Any preparation failure (C144A+C144C) - (C145A+C145C)

Attempt C145A+C145C

Reversion old channel C143A+C143EDrop radio C143B+C143FBSS Pb (C145A+C145C) - (C143A+C143E+C143B+C143F)

Success MC142E, C142A+C142C

Execution

OUTGOING INTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

(See comments)B8

Modified in B8

Detailed Pb available in standard type

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DR FAIL. CASES > Outgoing internal DR indicatorst see comments

Internal directed retry indicators Outgoing internal DR - indicatorsB8 (see comments)

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External directed retry indicators External DR - success

DR FAIL. CASES > External DR > successful case

MS serving_cell BSC MSC BSC target_cell MSTCH request queued < ------ASSIGNT REQUEST-------

EDR condition met ------ HO_REQUIRED ---------->MC144F ----------CR (HO_REQUEST) -----> MC820

< --------- CC ------------------------ ---- CHANNEL_ACTIVATION ------>< - CHANNEL_ACT_ACK-------------

< ----- HO_REQUEST_ACK -------- Start T9113(HO_COMMAND) MC821

< ------------------------- HO_COMMAND ------------------------------------------------------ < ---- HO_ACCESS -----C145B+ C145D Start T8 < ---- HO_ACCESS -----

< ------ HO_DETECTION--------------< -- HO_DETECTION -------------- --- PHYSICAL_INFO -->

< --- SABM ---------------< ----- ESTABLISH_INDICATION ---- ----- UA -------------->

< ----------- HO_COMPLETE ----------------------------------------< --- HO_COMPLETE --------------- Stop T9113

< ---- CLEAR_COMMAND ------ MC642MC142F Cause : HO_SUCCESSFUL

Release of SDCCH Stop T8

The same external DR procedure leads to an incrementation of two sets of counters: incoming external HO counters for the target cell: MC820, MC821, etc.outgoing external DR counters for the serving cell: MC144F, MC142F, etc.

B8 (see comments)

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External directed retry indicators Outgoing external DR - failures

DR FAIL. CASES > Outgoing external DR failures

Directed Retry procedure from the serving cell point of view

Ø DR Preparation: l congestion on the target cell (no specific counter on the serving cell)l BSS problem (no specific counter)

Ø DR Execution: l radio problem: the MS reverts to the old channell radio problem: the MS dropsl BSS problem (no specific counter)

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External directed retry indicators Outgoing external DR - radio failure ROC

DR FAIL. CASES > Outgoing external DR fail: reversionold channel

MS serving_cell BSC MSC BSC target_cell MSASSIGNT REQUEST---------------------> TCH request queued

EDR condition met ---- HO_REQUIRED ------->MC144F ----------CR (HO_REQUEST) ------------------->

< -------- CC --------------------------------------- - CHANNEL_ACT ---------->< --- CHA_ACT_ACK --------

< ----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included


C145B+ C145D X ---- HO_ACCESS ---------- SABM -------->< --- UA ------------- -- ESTABLISH_INDICATION->

----- HO_FAILURE (reversion to old channel) ------------------------------------------>C143C+ C143G ----- CLEAR_COMMAND ---------------------->

Radio interface fail : Reversion to old channel Release of connection

C145B,C143C: Forced DR

C145D,C143G: Normal DR

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External directed retry indicators Outgoing external DR - radio failure drop

DR FAIL. CASES > Outgoing external DR fail: drop

MS serving_cell BSC MSC BSC target_cell MSASSIGNT REQUEST---------------------> TCH request queued

EDR condition met ---- HO_REQUIRED ------->MC144F ----------CR (HO_REQUEST) ------------------->

< -------- CC --------------------------------------- - CHANNEL_ACT ---------->< --- CHA_ACT_ACK --------

< ----- HO_REQUEST_ACK----------------------- Start T9113 (HO-COMMAND) included


C145B+ C145D X ---- HO_ACCESS ---------- SABM --- X----- SABM --- X

----- SABM --- X

T8 expiry ----- CLEAR_REQUEST ->C143D+ C143H Radio interface message fail Release of connection

C145B,C143D: Forced DR

C145D,C143H: Normal DR

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DR FAIL. CASES > Outgoing external DR counters

External directed retry indicators Outgoing external DR - counters

Preparation Request MC144F, C144B+C144D

Any preparation failure (C144B+C144D) - (C145B+C145D)

Attempt C145B+C145D

Reversion old channel C143C+C143GDrop radio C143D+C143HBSS Pb (C145+C145D) - (C143C+C143G+C143D+C143H)

Success MC142F, C142B+C142D

Execution

OUTGOING EXTERNAL Directed Retry

REQUEST

CONGESTION

ATTEMPT


DROP RADIO

BSS PB

SUCCESS

BSS PB

Preparation Failure

Execution Failure

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External directed retry indicators Outgoing external DR - indicators

DR FAIL. CASES > Outgoing external DR indicatorst See comments

170

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ANNEX 4



1.340

t Signaling Links

A-Interface MT-Link signaling #7 System with SCCPMSC BSC

BSC BTSAbis Interface RSL with LAPD Protocol

BTS MSAir-Interface (CCCH/SACCH/FACCH) with LAPDm Protocol

BSC OMC-ROML Link with X25 connection LAPB Protocol


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The reference Model

7 Application

6 Presentation

4 Transport

5 Session

2 Data Link

3 Network

1 Physical

User of Transport Service

Transport ServiceNetworkService


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t Layer 1l Physical; Responsible for the transparent transmission of

information across the physical medium (HDB3, PCM, AMI)t Layer 2l Data Link; Responsible for providing a reliable transfer

between the terminal and the network (#7, LAPD,etc.)t Layer 3l Network; responsible for setting up and maintaining the

connection across a network (CM, MM, RR, Message routing, etc.)


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t Layer 4l Transport; responsible for the control of quality of service

(Layer of information)t Layer 5l Session; Handles the coordination between the user

processes (Set up transfer of information)t Layer 6l Presentation; responsible for ensuring that the information

is presented to the eventual user in a meaningful way (Type format. Ex. ASCII)

t Layer 7l Application; provides user interface to lower levels

(Operating System)


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BTS PSTNISDN

Air Intfc Abis Intfc A Intfc B .. F Intfc

MS BSC MSC

CM

MM

RR

LAPDm

digit

radio

RR BSSAP

LAPDm LAPD

digit

radio64 kb/s 64 kb/s 64 kb/s 64 kb/s

LAPD

RR

BTSM

BSSAP

CM

MM

BSSAP

SCCP

MTP

SCCP

MTP LAYER 2

LAYER 1

LAYER 3


t BSS protocol stacks

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SSCS

SSTM 3

SSTM 2

SSCS

SSTM 3

SSTM 2

SSGT

MAP

SSGT

MAP

SSCS

SSTM 3

SSTM 2

PCM TS

DTAP

SSCS

SSTM 3

SSTM 2

PCM TS

DTAP

LAPDLAPDm LAPD

SS (SMS)SS (SMS)

BSSMAP

MM

CC

BSSMAPRR

RR

RR' BTSMBTSM

LAPDm

(SMS)SSCC

MM

(Relay)

MS BTS BSC MSC / VLR NSS(ex. : HLR)

Um A bis A (D)1

2

3

(Relay

64 kbit/sor PCM TS

64 kbit/sor PCM TS PCM TS PCM TSPhycal

Layer

t BSS protocol stacks (detailed)

PhycalLayer

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t Signaling on the A Interfacel Uses #7 with Signaling Connection Control Part (SCCP)

with a new Application Base Station Application Part (BSSAP). BSSAP is divided into Direct Transfer Application Part (DTAP) and Base Station Subsystem Management Application Part (BSSMAP)

DTAP

BSSMAP

SCCP

MTP 1-3

User Data

Layer 1-3

BSSAP


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t BSSMAPl Contains the messages, which are exchanged between the BSC and the

MSC and which are evaluated from the BSC. l In fact all the messages, which are exchanged as RR (Radio Resource

Management Services between the MSC, BSC and MS). Also control Information concerning the MSC and BSC.

l Example: Paging, HND_CMD, Reset

t DTAPl Messages which are exchanged between an NSS and an MS

transparent. In this case, the BSC transfers the messages without evaluation transparent. Mainly Messages from Mobility Management(MM) and Call control (CC)


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t Relationship between DTAP, CC, MM, BSSMAP, RR

MS BSS MSC

Call Control (CC) DTAP

Radio Resource (RR)BSSMAP


Back

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ANNEX 5

B8 Improvements summary

B8 Improvements summaryB8

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t Location Services (LCS)t SDDCH Dynamic allocationt Counters Improvement

l Inter PLMN HOl 3G to 2G HO (and 2G to 2G only)l Dual band HO (New type: 32)l LapD congestion counterl QOS Followup

è TCH assignment failure BSS PB now detailedè HO Attempts for Fast Traffic added in type 110è AMR counters added in type 110è MS penetration (per speech version and channel type) was type 1 counters

now available in type 110è HO Causes: type 26 extended from 1 to 40 cellsè Directed retry: type 29 becomes a standard (for PMC)

B8 Improvements summaryB8

Qos and Traffic Load b8 8as902001424vhzza3

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