3G RANOP RU40 NSN Call Setup and Capacity Optimization

18/08/2015 1 © Nokia 2014 RN3703 – 50A

Call Setup and Capacity Optimization

• RN3703 – 50A

© Nokia 2014 RN3703 – 50A 18/08/2015 2

Module Objectives

At the end of the module you will be able to:

• Monitor and analyse all aspects of call and data session setup using network observability

• Examine sample or live measurement data for call setup issues

• Propose optimisation actions to resolve call setup issues

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Content

• Introduction

• RRC Setup

• RAB Setup

• Packet Session Setup

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Content

• Introduction

- Terms definition • RRC connection, • RAB setup, • Radio Bearer, • Radio Link, • data session

- Phases of RRC connection and RAB

• RRC Setup

• RAB Setup


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Introduction Terms definition

RRC connection setup RAN resources are reserved for signalling connection between UE and RNC

RRC access Connection between UE and RRC

RRC active UE has RRC connection. If dropped, also active RAB is dropped.

RAB setup Attempts to start the call

RAB setup access RAB active phase

UE has RAB connection

CSSR affected if any of the followings take place. • RRC Conn. Setup Fail • RRC Conn. Access Fail • RAB Setup Fail • RAB Setup Access Fail

RRC Drop

Setup

Complete

Access

Complete

Active

Complete

Setup Access Active

Att

em

pts

Setup failures (blocking)

Access failures

Acc

ess

Active

Release

Active

Failures

Su

cce

ss

Phase:

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Content

• Introduction

- Terms definition

- Phases of RRC connection and RAB

• RRC Setup

• RAB Setup


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Introduction RRC Connection Setup & Access and Active

RRC ACCESS fails if the UE does not reply to RRC: RRC CONNECTION SETUP message with the RRC: RRC CONNECTION SETUP COMPLETE message in given time, if the BTS reports a radio link synchronisation failure or in an RNC internal failure occurs

RRC SETUP fails if some of the needed resources (RNC, BTS, AIR, Transport) are not available. When an RRC setup failure occurs the RNC sends an RRC: RRC CONNECTION REJECT message to UE

RRC ACTIVE fails when an interface related (Iu, Iur , Iub, or Radio) or RNC internal failure occurs, and the failure causes the release of the RRC Connection. When an RRC active failure occurs, the RRC send a RANAP: IU RELEASE REQUEST to all involved CNs and waits for RANAP: IU RELEASE COMMAND message (s)

RRC ACTIVE release cause can be either

ISHO, IFHO, SRSN relocation or pre-emption

RRC SETUP phase

(Resource Reservation in RNC, BTS, Transport)

BTS UE RNC CN

RRC: RRC connection Request

RRC: RRC connection Setup

RRC: RRC connection Setup Complete

RR

C S

etu

p tim

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RRC: Initial Direct Transfer

RANAP: Initial UE Message

RANAP: Iu Release Command

UE-CN Signalling

(E.g. RAB Establishment and Release)

RRC: RRC connection Release

RRC: RRC connection Release Complete

Release RRC resources in RNC, BTS, Transport

RRC ACTIVE phase

RRC ACCESS phase

(RNC waits for Reply from UE)

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Introduction RAB Setup & Access and Active

RAB SETUP fails if some of the needed resources (RNC, BTS, AIR, Transport) are not available. When an RAB setup failure occurs the RNC sends a RANAP: RAB ASSINGMENT RESPONSE message to the CN with an appropriate failure cause

RAB ACCESS fails if the UE replies with an RRC: RADIO BEARER SETUP FAILURE message or the connection cannot be established in a give time. When a RAB access failure occurs, the RNC sends a RANAP: RAB ASSINGMENT RESPONSE message to the CN with an appropriate failure cause. Immediately after this, the RNC sends also a RANAP: IU RELEASE REQUEST to the CN and waits for RANAP: IU RELEASE COMMAND message

RAB ACTIVE fails when an interface related (Iu, Iur, Iub, or Radio) or RNC internal failure occurs, and the failure causes the release of the RAB connection.

• If the UE has more than one RAB connection and the failure is not so critical that it would lease to an RRC Connection drop, only the failed RAB connection is released. The RNC sends a RANAP: RAB RELEASE REQUEST message to the CN and waits for a RANAP: RAB RELEASE COMMAND or RANAP: IU RELASE COMMAND from CN

• Otherwise, both the RRC connection and RAB connection (s) are released. The RNC send a RANAP: IU RELASE REQUEST message to the CN and waits for a RANAP: IU RELEASE COMMAND MESSAGE from the CN

RAB Reconfiguration Actions

(Reconfigure RAB resources in RNC, BTS, Transport)

BTS UE RNC CN

RRC: Radio Bearer Setup

RAB SETUP phase

(Resource Reservation in RNC, BTS, Transport)

RAB ACCESS phase

(RNC waits for Reply from UE)

RRC: RB Setup Complete

RA

B S

etu

p tim

e

RRC: RB Reconfiguration

RANAP: RAB Assignment Response


Release RAB resources in RNC, BTS,

Transmission

RRC Connection Active Phase, UE-CN Signalling

RANAP: RAB Assignment Request


RAB ACTIVE phase

(User Plane Data Transfer)

RANAP: RAB Assignment Request with IE: RAB reconfiguration

RRC: Radio Bearer Release

RRC: RB Reconfiguration Complete

RANAP: RAB Assignment Request with IE: RAB Release

RRC: Radio Bearer Release Complete

RA

B H

old

ing

Tim

e

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Content

• Introduction

• RRC Setup

- RRC connection setup procedure

- RRC connection setup failures

- counters and KPIs for failure reasons

• RAB Setup


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RRC Setup RRC Connection Set-up

UE RNC WBTS

Admission Control

RRC: RRC CONNECTION REQUEST (RACH)

NBAP: RADIO LINK SETUP REQUEST

NBAP: RADIO LINK SETUP RESPONSE

RRC: RRC CONNECTION SETUP (FACH)

L1 Sync

NBAP: SYNCH INDICATION

RRC: CONNECTION SETUP COMPLETE (DCH)

ALCAP: ERQ

ALCAP: ECF

FP Downlink Sync

FP Uplink Sync

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RRC or RAB setup failures could be due to issues related to

• Coverage or interference

• Inter RNC problem

• Capacity

• Configuration & SW issues

Capacity issues could result in RRC/RAB setup failures related to

• BTS, for Baseband or Control Plane capacity issues,

• TRANS, for Iub capacity issues or

• AC for radio capacity issues (UL Load, DL Load and DL spreading codes)

Some type of RRC/RAB failures should NOT be present

• RRC_ACC_FAIL_RNC

• RAB_ACC_FAIL_xxx_RNC

SRNC relocation issues will also cause RRC/RAB failures

RRC Setup criteria for setup failure analysis

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RRC Setup RRC connection setup failures due AC

Existing M1001C3 RRC setup failure due AC counter can be updated either based on UL, DL or codes

• RU40 new counters to show detail AC failure cause

If setup failures due AC check M1001C731-C733

• Check UL Interference, DL Power & Code occupancy if there is need to upgrade radio capacity

• M1002C1 DCH REQ FOR SIG LINK REJECT IN UL IN SRNC --> Evaluate Prx Resource Problem

• M1002C2 DCH REQ FOR SIG LINK REJECT IN DL IN SRNC --> Evaluate Ptx Resource Problem

Included to RSRAN073 accessibility report

RNC_3200a RRC Setup FR due AC UL power

RNC_3201a RRC Setup FR due AC DL Power

RNC_3202a RRC Setup FR due AC Code

[RACH] RRC:RRC Connection Request

[FACH] RRC:RRC Connection Reject

M1001C3 RRC_CONN_STP_FAIL_AC: The number of RRC setup failures caused by Admission Control. The reason for the rejection can be uplink power, downlink power, spreading codes or a temporary failure in the cell common measurement reporting by the BTS

M1001C731 RRC_CONN_STP_FAIL_AC_UL: The number of RRC setup failures caused by AC because of uplink power limitation. M1001C3 is also updated along with this counter.

M1001C732 RRC_CONN_STP_FAIL_AC_DL: The number of RRC setup failures caused by AC because of DL power limitation. M1001C3 is also updated along with this counter.

M1001C733 RRC_CONN_STP_FAIL_AC_DR: The number of RRC setup failures caused by AC because of downlink spreading code congestion. M1001C3 is also updated along with this counter.

UE BTS

AC to check to accept or reject RRC Connection

Request

RNC

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RRC Connection Setup failures due BTS • Check BTS configuration in terms of WAM and BTS BB resources – Use BTS BB Counters (M5001,

M5006, M5008) in order to evaluate lack of BB resources • Evaluate NBAP counters (radio link reconfiguration failures) and KPIs for troubleshooting BTS

resources • Expand the Capacity or decrease the traffic offered to the site • (In case BTS is not responding delete and re-create COCO (ATM transport only))

RRC Connection setup failures due transmission • Evaluate Number of reconfiguration failure due the transmission • Expand the capacity or decrease the traffic offered to the site

For ATM based Iub • Check COCO Configuration • Use AAL2 Multiplexing in case of two WAM

For IP based Iub • Check IP based route parameters (ZQRL;)

RRC Setup RRC connection setup failures

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RRC Connection setup failures due RNC

• Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border)

• DMPG problem in RNC

• Required ICSU log tracing if no RNC fault or SRNC relocation problem

RRC Connection setup failure due ICSU overload

• ICSU Overload

RRC Setup failures due RNTI allocation fail

• RNC decides to reject RRC connection request due to RNTI allocation failure caused by RRMU overload

RRC Setup RRC connection setup failures

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RRC Setup Example: RRC Setup Failures

RRC Setup failures mainly due BTS and AC

Detail AC failure counters show that failures are mainly

coming from UL direction

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RRC Setup Example: RRC Setup Failures

• Using BTS/Cell level accessibility data/template we can monitor setup failures in site level

• Analysis show that there is 3 main offender causing setup failures due BTS.

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RRC Setup RRC Access Failure reasons

NBAP: Synchronisation Indication

L1 Synchronisation

RRC: RRC Connection Setup Complete (DCH)

L1 Synchronisation

X UE BTS RNC

X RRC Access Failures for L1 synchronization

NBAP: Synchronisation Indication

L1 Synchronisation

RRC: RRC Connection Setup Complete (DCH)

L1 Synchronisation

X UE BTS RNC

RRC Access Failures due to MS

Cell Reselections (no error)

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RRC Setup RRC Access Failure reasons

RRC Connection access fail radio

• Perform drive test to detect if UL or DL coverage lacks

- UL Coverage - > Tune cell dominance if the is UL interference

- DL Coverage - > Tune SCCPCH power if UE does not receive the RRC Setup messages

• If UE does not synchronize

- Tune CPICHToRefRABOffset vs. Qqualmin (or Qrxlevmin)

- Due to Increased interference with HSDPA this max radio link power for AMR (offset parameter) has been increased (0-> -2 dB)

RRC Connection access fail MS

• UL Coverage - > Tune Cell dominance in order to balance UL and DL (if UL interference is not the cause)

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RRC Setup RRC Connection & Access Analysis

If RRC setup/access failure due to Radio/MS, it is also possible to check whether UEs are located at distance area or close to cell edge area

• Propagation delay counters from RRC measurement M1006C128-C148 reports call setup distance during RRC connection request or cell update

• This give hints that either cells has large coverage area (tall sites with over-shooting) or non-optimum cell coverage from neighbouring cells

0

100000

200000

300000

400000

500000

600000

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

120.00%

average

CDF

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RRC Setup Example: RRC Access Failure Distribution

• Radio failures are dominant failure cause under this RNC

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RRC Setup RAN - MS Connection Establishment Counters

Correctly Received message RRC Connection Request Triggers: RRC_CONN_STP_ATT (M1001C0)

M1001C678 RRC_CONN_STP_ATT_CCH : The number of RRC connection requests that are

handled with CCH. Also counter M1001C0 is updated along with this counter.

M1006C203RRC_CONN_REJ_IUB_OVERLOAD

The number of RRC connection rejections due to Iub overload control. The counter is updated

when the RNC sends RRC CONNECTION REJECT message to the UE because NBAP

operations are restricted due to window-based self adjusting Iub overload control, C-NBAP

overload or overload indication received from the BTS.

Also M1006C21 is updated along with this counter.

M1006C204RRC_CONN_REJ_MAX_REGIST

The number of RRC connection rejections due to maximum amount of registrations and inter-

RAT cell reselections per ICSU. Counter is updated when the RNC sends RRC CONNECTION

REJECT message to the UE due to attempting registration or inter-RAT cell reselection, and the

maximum number of such procedures per ICSU has been exceeded.


M1006C205RRC_CONN_REJ_CENT_UNIT_OVERL

The number of RRC connection rejections due to centralized signaling unit RSMU overload.

Counter is updated when the RNC sends RRC CONNECTION REJECT message to the UE

because RSMU unit is overloaded.


M1006C206RRC_CONN_REJ_BUF_LIMIT_CTRL

The number of RRC connection rejections due to buffer limit control.

Counter is updated when the RNC sends RRC CONNECTION REJECT

message to the UE because the number of unhandled messages in a

signalling unit has exceeded a specified threshold value.

Also M1006C21 and M1001C618 are updated along with this counter.

M1006C207RRC_CONN_REJ_CN_FAIL

The number of RRC connection rejections due to the Core Network failure. Counter updated

when the RNC sends an RRC CONNECTION REJECT message to the UE because the core

network connection is recovering from a failure or both CS and PS core networks are out of use.


M1006C208RRC_CONN_REJ_RNC_RESTART

The number of RRC connection rejections due to RNC recovery after

restart. Counter updated when the RNC sends RRC CONNECTION

REJECT message to the UE because the RNC has recently restarted

and the maximum number of RRC connection establishments is limited

until a guard timer expires.


[RACH] RRC:RRC Connection Request

UE RNC BTS

AC to check to accept or reject RRC Connection Request

[FACH] RRC:RRC Connection Reject

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RRC Setup Example: RRC connection reject counters

• RRC Connection reject due Iub Overload and max registrations.

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Content

• Introduction

• RRC Setup

• RAB Setup

- CS RAB setup procedure, counters and KPIs for setup failure reasons

- PS RAB setup procedure, counters and KPIs for setup failure reasons


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Content

• Introduction

• RRC Setup

• RAB Setup




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RAB Setup CS RAB setup

Radio Link Reconfiguration Commit

AAL2SIG:ERQ

RAB Assignment Request

Facility

Call Proceeding

Setup

Security Mode Complete

Security Mode Command

Common ID

UE RNC MSS/MGW Node B

RRC Connection Establishment

Initial Direct Transfer (CM Service Request) SCCP: Connection Request

SCCP: Connection Confirm

Location Reporting Control

Radio Link Reconfigure Prepare

Radio Link Reconfigure Ready

AAL2SIG:ERQ

AAL2SIG:ECF

FP: Downlink Sync

FP: Uplink Sync

AAL2SIG:ECF

Radio Bearer Setup

Radio Bearer Setup Complete

Admission Control

RAB Assignment Response

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RAB Setup failures due AC for CS voice

RAB Setup failures due AC

• Typically indicate lack of Air interface capacity

- UL load

- DL load

- DL codes

Existing M1001C80 RAB setup failure due AC for Voice counter can be updated either based on UL, DL or codes

• RU40 new counters to show detail AC failure cause

RAB Setup RAB setup & Access Fail Root Cause Analysis

RNC_3203a RAB Setup Access FR for CS Voice due to UL PW

RNC_3204a RAB Setup Access FR for CS Voice due to DL PW

RNC_3205a RAB Setup Access FR for CS Voice due to Code

M1001C80 RAB_STP_FAIL_CS_VOICE_AC When the RNC decides to reject the CS voice RAB request because the admission control entity reports a failure (excluding frozen BTS reason). This happens before the RRC: RADIO BEARER SETUP message would be sent to the UE. (See the section "Failure and abnormal release causes" for more details.)

M1001C734 RAB_STP_FAIL_CS_VOICE_AC_UL The number of RAB setup failures caused by AC because of UL power limitation for CS voice. M1001C80 is also updated along with this counter. Updated: When the RNC decides to reject the CS voice RAB request because of UL power AC.

M1001C735 RAB_STP_FAIL_CS_VOICE_AC_DL: The number of RAB setup failures caused by AC because of DL limitation for CS voice. M1001C80 is also updated along with this counter. Updated: When the RNC decides to reject the CS voice RAB request because of DL power AC

M1001C736 RAB_STP_FAIL_CS_VOICE_AC_COD: The number of RAB setup failures caused by AC because of DL spreading code congestion. M1001C80 is also updated along with this counter Updated: When the RNC decides to reject the CS voice RAB request because of DL spreading code congestion.

UE RNC BTS

AC to check to accept or reject RRC Connection Request


CN

RANAP: RAB Assignment Response: Failure

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RAB Setup Example of RRC and CS Voice setup failures

• Example from test network – this is in RNC/daily level as number of failures is very low.

• Typically monitored in cell level

• For both RRC and Voice, the capacity bottleneck is in DL.

• New counters does not cover all AC failure causes. It is possible that old M1001C3/C80 shows higher value. (for example cases when AC queue is full, no answer from BRM etc)

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RAB Setup failures due BTS

• Check BTS BB resources – Use BTS counters (M5001, M5006, M5008) in order to evaluate lack of BTS BB resources

• Evaluate NBAP Counters (radio link reconf. Add failures) and KPIs for troubleshooting BTS resources.

• Expand the capacity or decrease the traffic offered to the site

RAB Setup Failures for CS Voice can be monitored separately for

- M1001C621 RAB Setup fail CS Voice Iur_TR

- M1001C625 RAB Setup fail CS Voice Iu_CS

- M1001C619 RAB Setup fail CS Voice License

Related to RNC licensed capacity – only for Voice


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RAB setup failures due transmission

• Evaluate Number of reconfiguration failure due the transmission

• Check M1005C128 CANC_ADD_SRNC_TRAN_STP_FAIL (The number of cancelled synchronised radio link reconfigurations on SRNC side due to a transmission setup failure or RNC DMPG/DSP resource allocation failure)

For ATM based Iub • Check RAB_STP_FAIL_XXX_IUB_AAL2, M1001C531-C533

• Check COCO Configuration

For IP based Iub

• Check IP based route parameters (ZQRL;)

Transmission Setup failures are often CAC failures

• For ATM reservation M550 and for ATM CAC rejects M800

• For IP reservation M568 and for IP CAC M804


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RAB Setup Example: RAB setup failure distribution - Voice

• Mainly AC failures, but RNC failures are relevant as well.

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RAB Setup Example: RAB setup for Voice – transmission failure details

Note!! Scale

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Content

• Introduction

• RRC Setup

• RAB Setup




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Packet RAB Setup Packet RAB allocation procedure


UE RNC SGSN Node B


Uplink Direct Transfer : Activate PDP context request (DCH) Direct Transfer : Activate PDP context request

RRC: Radio Bearer Setup

Direct Transfer: Activate PDP Context Accept Downlink Direct Transfer : Activate PDP Context Accept (DCH)

Admission Control

RAB Assignment Response

GPRS Attach

Radio Bearer Setup Complete

Measurement Control

Measurement Control

Connection established (CELL_DCH state)

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RAB Setup Example: RAB setup failure distribution - PS

• Small amount of RNC failures (note scale)

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RAB Access Failures MS

• Evaluate cell resourece Prx and Ptx (for example high uplink interference)

• Check RB reconfiguration failure ratio (if ATO settings is insufficient, rec. 500ms)

RAB Access Failures RNC

• Typically RNC fault or incoming SRNC relocation failure (inter-RNC border)

• Need ICSU log tracing if there is no obvious reason


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RAB Setup Example: RAB Access failure distribution - Voice

• UE related failures

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RAB Setup Example: RAB Access failure distribution - PS

UE related failures also in PS Note the scale.

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Content

• Introduction

• RRC Setup

• RAB Setup


- PS allocation procedure

- HSDPA and HSUPA accessibility analysis

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Content

• Introduction

• RRC Setup

• RAB Setup




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Packet Session Setup PS allocation procedure

UE RNC SGSN Node B


Measurement Report : e4a

NBAP: Radio Link Reconfigure Prepare

GPRS Attach

Connection established (CELL_DCH state)

AAL2SIG:ECF

AAL2SIG:ERQ


FP: Downlink Sync

FP: Uplink Sync


RRC: Radio Bearer Reconfiguration (DCH)

RRC: Radio Bearer Reconfiguration Complete (DCH)

Measurement Control

Data Flow

Admission Control

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Separate Packet call counters could be used in UL/DL to see the accessibility/retainability of DCH radio bearers (R99 NRT, HSDPA, HSUPA)

• There could be multiple packets inside single RAB

Packet calls starts with user plane capacity allocation (transfer from FACH/PCH, DCH 0/0) and ends with dedicated resource release (transfer back to FACH/PCH, DCH 0/0, RAB release, outgoing relocation, HHO, ISHO)

• There are counters for the following channel combinations:

- Rel99 DL = DCH UL = DCH

- HSDPA DL = HS-DSCH UL = DCH

- HSUPA DL = HS-DSCH UL = E-DCH

• There are counters for the following events

- Attempts, Allocations, Channel switches, Setup failures, Normal and abnormal releases

Packet Session Setup Packet Call Counters

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Normally CCSR for NRT DCH (0/0), RNC_576d, is showing about 100 %, so it is not useful for data call issues (PS RAB setup)

Packet calls starts with user plane capacity allocation (transfer from FACH/PCH, DCH 0/0) and ends with dedicated resource release (transfer back to FACH/PCH, DCH 0/0, RAB release, outgoing relocation, HHO, ISHO)

• Initial Setup fail procedure

- AC failure : lack of DL power or high interference

- BTS failure: lack of HW capacity

- DMCU failure: lack of DSP resources in RNC

- TRANS failure: lack of Iub capacity (COCO parameters)

- UE failure: UE internal problem (not capability issue)

• Separate Packet SSSR for R99 NRT, HSDPA and HSUPA to see the main failure type

Packet Session Setup Packet Call Setup Failures

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Packet Session Setup PS RAB Upgrade or HSDPA/HSUPA Activation

If RNC receives RRC: Measurement Report indicating event 4a when UE has been

allocated DCH0/0 or in cell_PCH state RNC receives Cell Update indicating need

for dedicated channel (i.e. cause UPLINK DATA TRANSMISSION), following

counter is incremented:

M1022C0 PS_SESSION_REQ_UL

If the network wants to initiate any downlink activity and the UE is in Cell_PCH

state, it needs to make a paging request. Counter M1022C1

PS_SESSION_REQ_DL is incremented when RNC receives RRC: CELL UPDATE

message with the cause PAGING RESPONSE

NOTE: These counters are NOT incremented when resources (DMPG) are re-

allocated due to: Direct switching from DCH xx/yy to HS-DSCH/E-DCH or HS-

DSCH/DCH

In case of inter RNC HHO or SRNC relocation counter M1022C2

PS_SESSION_REQ_OTHER is incremented when RANAP: RELOCATION

REQUEST message request is received

Note: PS ISHO do not use relocation signaling as it is a normal PS call setup

where the resources are reserved by UL/DL capacity request


UE Node B RNC

AC to check to accept or

reject RAB Assignment

Request

SGSN

[DCH] RRC: Radio Bearer Setup

[DCH] RRC: Radio Bearer Setup Complete

RANAP: RAB Assignment Response: Success

[DCH] RRC: Measurement Control

Direct Transfer : Activate PDP Context Accept

[DCH] RRC: Measurement Report


NBAP: RL Reconfiguration Prepare

NBAP: RL Reconfiguration Failure

AC to check to accept or

reject Capacity request

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Packet Session Setup RU40 New Counters – PS setup failures due AC

Resource reservation happens during PS user plane allocation.

-If user plane allocation is rejected by the admission control. PS call counters

- M1022C9 Packet Call Setup Fail due to AC for Interactive

- M1022C10 Packet Call Setup Fail due to AC for Background

are updated

• RU40 AC failures counters per cause (UL Power, DL Power and DL codes)

In case the starting state of the terminal is Cell_FACH (Cell_PCH) or DCH 0/0 and AC rejects the bit rate allocation and terminal stays at Cell_FACH or DCH0/0, following counters are incremented: M1022C9 PS_SETUP_FAIL_AC_INT M1022C10 PS_SETUP_FAIL_AC_BGR

M1022C234 PS_SETUP_FAIL_AC_UL_NRT: The number of packet call setup failures caused by Admission control because of UL power limitation for PS NRT calls. M1022C9 or M1022C10 is also updated along with this counter.

M1022C235 PS_SETUP_FAIL_AC_DL_NRT: The number of packet call setup failures caused by admission control because of downlink power limitation for PS NRT calls. M1022C9 or M1022C10 is also updated along with this counter.

M1022C236 PS_SETUP_FAIL_AC_COD_NRT: The number of packet call setup failures caused by admission control because of downlink spreading code congestion. M1022C9 or M1022C10 is also updated along with this counter.


AC to check to accept or reject RAB Assignment Request

[DCH] RRC: Radio Bearer Setup

[DCH] RRC: Radio Bearer Setup Complete

RANAP: RAB Assignment Response: Success


Direct Transfer : Activate PDP Context Accept

[DCH] RRC: Measurement Report


AC to check to accept or reject Capacity request

UE RNC BTS SGSN

Note: These counters are only incremented in case of initial allocation for terminal has been Cell_FACH (Cell_PCH) or DCH0/0 (counters incremented to main cell only).Successful Packet Call setup allocations and allocation attempts due to Incoming relocation or Inter-RNC HHOs are not counted separately.

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Packet Session Setup Example: PS Setup failure distribution

Failures mainly related to UE and AC.

• Detail AC failure analysis shows UL power

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Packet Session Setup HSDPA Accessibility Analysis

• High level HSDPA Accessibility analysis can be done with traffic measurements

• RNC_605b HSDPA Resource Accessibility for NRT Traffic

• For Packet call measurements, the relevant KPI is RNC_914c

Low HSDPA

accessibility (cell)

Check Number of simultaneous HSDPA users in

BTS or cell level depending on the scheduler type

Check BH Channel Element resource Usage

(Lack of CE for UL return Channel)

Check BH UL Power Congestion

(Lack of Radio resources for UL return Ch.)

Check BH AAL2 Iub congestion

(Lack of Iub resources for UL return Ch.)

Check RB reconfiguration failure rate

(Terminal Problem)

Check RNC Unit load (DMPG), max number of

users/RNC, DSP failures and faulty alarms

No Action

Needed

Too many HSDPA

users reached

HSDPA Setup Fail

due BTS

Rejection of UL

Return Channel

HSDPA Setup Fail

Iub (Both UL & DL)

HSDPA Setup Fail

UE

HSDPA Setup Fail

RNC Internal

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

© Nokia 2014 RN3703 – 50A 18/08/2015 49

Packet Session Setup HSDPA Activation (Without DRA for HSPA)

AAL2SIG:ECF AAL2SIG:ERQ


UE RNC SGSN Node B


PDP Established Measurement Report : e4a

FP: Downlink Sync FP: Uplink Sync

Radio Link Reconfiguration Commit RRC: Radio Bearer Reconfiguration (DCH)

RRC: Radio Bearer Reconfiguration Complete (DCH)

Measurement Control

AAL2SIG:ECF AAL2SIG:ERQ

FP: Downlink Sync

FP: Uplink Sync

HSDPA Traffic

HS-DSCH: Capacity Request

HS-DSCH: Capacity Allocation

UL NRT Return channel transport in Iub

HS-DSCH transport in Iub. DL:CAC in RNC already

Setup information for the UE


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Identify root cause of failure distribution and main failure contributor

1. HSDPA access failures due too many HSDPA users (RNC_660d)

- Check simultaneous HSDPA users

2. If high HSDPA access failure due UL DCH (RNC_661d)

- Rejected HS-DSCH return channel due to lack of UL radio resources, UL load

3. If high HSDPA access failure UE (RNC_667d)

- Check RB reconfiguration failure rate

- ICSU log for UE types troubleshooting ?

4. If high HSDPA access failure due BTS (RNC_673d)

- Lack of BTS BB resources for UL return channel.

- Too SHO overhead – all branches must have enough BTS BB resources if UE is in SHO when HS-DSCH allocation started

Packet Session Setup HSDPA Accessibility analysis

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5. HS-DSCH setup failures due Iub transport

- Related to HSDPA UL return channel

- Evaluate number of reconfiguration failure due the transmission

- Check M1005C128 CAN_ADD_SRNC_TRAN_STP_FAIL

- Check RAB_STP_FAIL_XXX_IUB_AAL2, M1001C531-C533

6. HSDPA setup failures due RNC internal reason

- Check RNC unit load (DMPG)

- Max number of users in RNC

- DSP failures and faulty alarms

Packet Session Setup HSDPA Accessibility analysis

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Packet Session Setup Example: HSDPA setup failure distribution

Failures mainly related to UE, BTS and max users.

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3GPP TS32.405 Required Counters for HSDPA setup • M1005C241 MAC-d setup attempt for HSDPA • M1005C242 Success MAC-d setup for HSDPA • M1005C247 Failed MAC-d setup for HSDPA due the no response • M1005C248 Failed MAC-d setup for HSDPA due the RN layer • M1005C249 Failed MAC-d setup for HSDPA due to transport layer • M1005C250 Failed MAC-d setup for HSDPA due the protocol • M1005C251 Failed MAC-d setup for HSDPA due to MISC • M1006C149 RB Setup attempt for HSDPA • M1006C150 Successful RB Setup for HSDPA • M1006C192 RB Setup fail for HSDPA due no reply • M1006C193 RB Setup fail for HSDPA due UE

Dual Cell HSDPA Counters • M1005C252 MAC-D Setup attempt for DC HSDPA • M1005C254 Successful MAC-d setup for DC HSDPA • M1005C254 Failed MAC-d setup for DC HSDPA • M1006C209 RB Setup attempt for DC HSDPA • M1006C210 Successful RB setup for DC HSDPA • M1006C211 RB setup fail for DC HSDPA due to no Reply • M1006C212 RB Setup fail for DC HSDPA due the UE

Packet Session Setup HSDPA Setup Counters

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Packet Session Setup HSDPA Activation, Cell DCH – HS-DSCH

Radio Link Reconfigure Failure

UE



UE Node B RNC

AC to check to accept or reject

Capacity request

M1005C241ATT_MACD_SETUP_FOR_HSDPA : The number of attempted radio link

setups/reconfigurations for HSDPA MAC-d flow. Updated when the RNC sends NBAP:

RADIO LINK SETUP REQUEST or NBAP: RADIO LINK RECONFIGURATION PREPARE

with information to configure HSDPA MAC-d flow for the radio link

M1005C247FAIL_MACD_SETUP_HSDPA_NORESP : The number of HS-DSCH Mac-d flow

setup failures due to BTS not responding. Updated when the RNC does not receive NBAP:

RADIO LINK SETUP RESPONSE, NBAP: RADIO LINK SETUP FAILURE, NBAP: RADIO

LINK RECONFIGURATION READY or NBAP: RADIO LINK RECONFIGURATION FAILURE

and a timer expires

M1005C248FAIL_MACD_SETUP_HSDPA_RNL : The number of failed HS-DSCH Mac-d

flow setup failures due to radio network layer cause. Updated When the BTS responds with

NBAP: RADIO LINK SETUP FAILURE or NBAP: RADIO LINK RECONFIGURATION

FAILURE including error cause in radio network layer category

M1005C249FAIL_MACD_SETUP_HSDPA_TR : The number of failed HS-DSCH Mac-d flow

setup failures due to transport network layer cause. Updated when the BTS responds with


FAILURE including error cause in transport layer category.

M1005C250FAIL_MACD_SETUP_HSDPA_PROT : The number of failed HS-DSCH Mac-d

flow setup failures due to protocol cause. Updated when the BTS responds with NBAP:

RADIO LINK SETUP FAILURE or NBAP: RADIO LINK RECONFIGURATION FAILURE

including error cause in protocol category.

M1005C251FAIL_MACD_SETUP_HSDPA_MISC : The number of failed HS-DSCH Mac-d

flow setup failures due to miscellaneous cause. Updated when the BTS responds with


FAILURE including error cause in miscellaneous category.

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Packet Session Setup HSDPA Activation, Cell DCH – HS-DSCH

AAL2SIG:ECF

AAL2SIG:ERQ


UE




RRC: Radio Bearer Reconfiguration (DCH)

UE Node B RNC

AAL2SIG:ECF

AAL2SIG:ERQ


M1006C149ATT_RB_SETUP_HSDPA : The number of attempted Radio Bearer setups for HSDPA. Updated when the RNC sends RRC: RADIO BEARER SETUP or RRC: RADIO BEARER RECONFIGURATION to the UE with information to configure the radio bearer to use HS-DSCH

M1006C209ATT_RB_SETUP_DCHSDPA The number of attempted Radio Bearer setups/reconfigurations for DC-HSDPA. Includes initial DC-HSDPA allocations, reconfigurations from SC-HSDPA to DC-HSDPA, hard handovers and serving cell changes. Also M1006C149 is updated along with this counter if the radio bearer was not using HSDPA previously. Counter is updated when the RNC sends RRC: RADIO BEARER SETUP, RRC: RADIO BEARER RECONFIGURATION, RRC: PHYSICAL CHANNEL RECONFIGURATION or RRC: TRANSPORT CHANNEL RECONFIGURATION to the UE with information to configure the radio bearer to use DC-HSDPA

M1006C211FAIL_RB_SETUP_DCHSDPA_NOREP The number of failed Radio Bearer setups/reconfigurations for DC-HSDPA due to UE not responding. Also M1006C192 is updated along with this counter if the radio bearer was not using HSDPA previously. Counter is updated when the UE does not respond to the RRC: RADIO BEARER SETUP, RRC: RADIO BEARER RECONFIGURATION, RRC: PHYSICAL CHANNEL RECONFIGURATION or RRC: TRANSPORT CHANNEL RECONFIGURATION message sent by the RNC for DC-HSDPA establishment and a timer expires in the RNC.

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Direct resource allocation for HSPA feature (DRAenabled) allocates HSPA during RAB setup establishment which replaces the allocation of a 0/0 kbps.

• Direct resource allocation is applicable to full HSPA connections using PS NRT Interactive or Background traffic classes.

• In case HSPA allocation is not possible due to BTS, TRS or DSP congestion, no further attempt shall be made and DCH 0/0 shall be allocated and TVM started as per existing principles.

• There is own counters to monitor DRA attempts and Success

• If F-DPCH is in use, and SRB are already on HSPA during the “initial” NRT-RAB setup phase, the Direct Resource Allocation for HSPA is used as a default.

• I.e. the MAC-d flow for NRT-RAB is allocated during the RB setup without DCH-0/0 allocation and waiting for UL/DL capacity request first.

• If there aren’t the required resources (radio, BTS, transport, DMCU, …) for an immediate u-plane setup available, the NRT-RB shall be mapped to DCH-0/0 as in the “classic” NRT-RAB setup scenario and the RAB Assignment Request is acknowledged to the SGSN. After this the (next) UL/DL capacity request triggers the next resource allocation attempt

Packet Session Setup Direct Resource Allocation for HSPA

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Packet Session Setup Direct Resource Allocation for HSPA

RNC UE BTS

HSPA/HSDPA capacity

request for direct resource

allocation

NBAP: Radio Link Reconfiguration Prepare

NBAP: Radio Link Reconfiguration Ready

NBAP: Radio Link Reconfiguration Commit

RRC: Radio Bearer Setup (HS-DSCH + E-DCH)

SGSN


L2 resource allocation and Iub transmission

setup

GTP tunnel creation

RRC: Radio Bearer Setup Complete


M1002C672ATT_HSPA_DIREAL_BGR,

M1002C673ATT_HSPA_DIREAL_INT

The number of HS-DSCH/E-DCH or HS-DSCH/DCH allocation attempts by

Direct Resource Allocation for background/interactive traffic class. This

counter is updated for the first cell that is attempted to make HS-DSCH

serving cell. Possible attempts to other cells after a failure of the initial cell

are not anymore counted and thus the counter is updated only once per RAB

Assignment Request. Counter is updated when HS-DSCH/E-DCH or HS-

DSCH/DCH user plane setup is triggered immediately upon receiving

RANAP: RAB ASSIGNMENT REQUEST.

M1002C674ALLO_SUCC_HSPA_DIREAL_BGR,

M1002C675ALLO_SUCC_HSPA_DIREAL_INT

The number of successful HS-DSCH/E-DCH or HS-DSCH/DCH allocations

with Direct Resource Allocation for background/interactive traffic class. This

counter is updated for the HS-DSCH serving cell. In case of retries were

done to multiple cells, attempt counter M1002C672 could have been updated

to different cell than this allocation counter. Also counter M1002C389 is

updated along with this counter. Counter is updated when the UE responds

with RRC: RADIO BEARER SETUP COMPLETE indicating a successful user

plane setup

© Nokia 2014 RN3703 – 50A 18/08/2015 58

Packet Session Setup HSUPA Accessibility Analysis

HSUPA Accessibility Analysis can be done based on Traffic measurements

• RNC_913b HSUPA Resource Accessibility for NRT Traffic

For packet call measurement, the relevant KPI is RNC_915c

Low HSUPA

accessibility

Check Number of simultaneous HSUPA

users

Check BTS BB resource usage (BTS in state

that no capacity available for EDCH)

HSUPA is not supported in SHO branch

Check BTS BB resource usage

Check RB reconfiguration failure rate

(Terminal problem)

Check AAL2 connections (CID) or signalling

problems

No Action Needed

Too many HSUPA users

reached

UL DCH selected due

BTS HW

HSUPA fail due Not

Acceptable Active Set

HSUPA Setup fail BTS

HSUPA Setup Fail UE

HSUPA Setup Fail

TRANS

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

Go for troubleshooting (ICSU logs etc)

E.g. RNC internal failures HSUPA Setup fail Other

Yes

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If HSDPA setup is failing also HSUPA setup will fail, but it could be also that only HSUPA will fail.

The reasons are similar to HSDPA:

• RNC_956d EDCH setup FR due to BTS (RL reconfiguration failure to RNC) • RNC_1105d EDCH setup FR due to Transport (RL reconfiguration cancel from RNC) • RNC_1106d EDCH setup FR due to UE (RB reconfiguration failure from UE) • RNC_1104d EDCH setup FR due to Other failures (RNC internal reason)

Due too many users

• RNC_968d UL DCH selected due too many HSUPA users

HSUPA setup failed due the BTS reports HSUPA cannot be allocated.

• RNC_957d EDCH not selected due the BTS HW (BTS sent radio resource measurement report

EDCH cannot be allocated in case HSUPA is not supported in SHO branch

• RNC_1103d EDCH allocation FR due to not acceptable active set

Packet Session Setup HSUPA Accessibility Analysis

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•Selection between DCH and E-DCH is completed when RNC receives the Uplink or downlink capacity request

Packet Session Setup HSUPA Selection & Setup failures due BTS

UE RNC Node B

PDP Established



NBAP: Radio Link Reconfigure Failure

AC to check to accept or reject

Capacity request

AC to continue or cancel the E-

DCH setup based on

acceptable (or not) AS

The number of E-DCH setup failures due to BTS for background and interactive class connections:

M1002C526 SETUP_FAIL_EDCH_BTS_BGR,

M1002C525 SETUP_FAIL_EDCH_BTS_INT

The counters count the E-DCH setup failures, that can happen in:

• channel type switching from non-E-DCH (FACH, DCH xx/yy, HS-DSCH/DCH) to HS-DSCH/E-DCH

• initial allocation of user plane from DCH 0/0 to HS-DSCH/E-DCH

• soft/softer handover E-DCH branch addition

Note that the BTS failure counters are updated only for the cells in which the BTS failure occurred

If the BTS reports that no HSUPA cannot be allocated then counter (each BTS sends the Radio Resource

Measurement reports to RNC indicating the HSUPA availability):

M1002C517 UL_DCH_SEL_BTS_HW_INT or

M1002C518 UL_DCH_SEL_BTS_HW_BGR is incremented

© Nokia 2014 RN3703 – 50A 18/08/2015 61

When E-DCH cannot be setup due to uplink admission control rejection. This happens when the averaged estimated Rel99 interference exceeds the limit value defined as the maximum of the values of the management parameters PrxTarget, PrxTargetMax and PrxMaxTargetBTS.

• The counter is updated only for initial E-DCH allocation attempts, not for channel type switches or serving cell changes.

• TN159 to activate power based AC for HSUPA

• New HSUPA reject due AC counters are added to RNC_913b and RNC_923d

• RNC_2713a EDCH setup FR due to AC rejection can be used to monitor HSUPA AC failure

Packet Session Setup HSUPA Setup Failures due Admission Control

Counter id Counter Name Updated

M1002C681 SETUP REJECT EDCH AC INT

When E-DCH cannot be setup due to UL AC rejection. This happens when the averaged

estimated Rel99 interference exceeds the limit value defined as the maximum of the

values of the management parameters PrxTarget, PrxTargetMax and

PrxMaxTargetBTS.

M1002C682 SETUP REJECT EDCH AC BGR

When E-DCH cannot be setup due to UL AC rejection. This happens when the averaged

estimated Rel99 interference exceeds the limit value defined as the maximum of the

values of the management parameters PrxTarget, PrxTargetMax and

PrxMaxTargetBTS.

© Nokia 2014 RN3703 – 50A 18/08/2015 62

Packet Session Setup Example: HSUPA accessibility analysis

Mainly UE and BTS failures Max users triggers also.

3G RANOP RU40 NSN Call Setup and Capacity Optimization

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