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Transcript of 07 HandoverControl 2006 Partner
1 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Course Content
• Radio Resource Management Overview
• Parameter Configuration
• Common Channels & Power Control
• Load Control
• Admission Control
• Packet Scheduling
• Handover Control
• Resource Manager
2 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Course Objectives
At the end of the course you will be able to:
• Name and describe the different Handover types
• Describe and list the steps of the Handover procedure for each Handover type
• Name and describe the main RAN parameters related to Handover reporting triggering
• Describe the main difference between inter system Handover and other Handover types
• Name and describe the main RAN parameters related to inter system Handover
3 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing• Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Measurements• HO decisions
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
4 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Intra-Frequency Handovers• Softer Handover
• Handover between sectors of the same Node B (handled by BTS)• No extra transmissions across Iub interface• Maximum Ratio Combining (MRC) is occurring in both the UL and DL
• Soft Handover• MS simultaneously connected to multiple cells (from different Node Bs)• Extra transmission across Iub, more channel cards are needed (compared to non-SHO)• Mobile Evaluated Handover (MEHO)• DL/UE: MRC & UL/RNC: Frame selection combining
• Hard Handover• Arises when inter-RNC SHO is not possible (Iur not supported or Iur congestion)• Decision procedure is the same as SHO (MEHO and RNC controlled)• Causes temporary disconnection of the (RT) user
• Inter-Frequency Handover• Can be intra-BS, intra-RNC, inter-RNC • Network Evaluated Handover (NEHO)• Decision algorithm located in RNC
• Inter-RAT Handover• Handovers between GSM and WCDMA (NEHO)
Handover Types
5 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
6 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
HC Parameter Database Structure
• RNC = Radio Network Controller level parameters
• WBTS = Node B level parameters
• WCELL = Cell level parameters
• FMCx = Frequency Measurement Control parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)
• ADJx = Adjacent Cell parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)
• HOPx = Handover Path parameters (S=intra- frequency set; I=inter-frequency; G=inter-RAT)
S:Intra-FrequencyS:Intra-
Frequency
I:Inter-FrequencyI:Inter-
Frequency
G:Inter-System
G:Inter-System
WCELL
ADJG
ADJI
ADJS
WBTS
RNC
FMCS
FMCI
FMCG
100
100
100
HOPS 100
HOPI 100
HOPG 100
32
48
32
7 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SHO: Neighbour Cell Definition
ADJS
ADJS
ADJS
FMCS(NRT)
FMCS(RT)
HOPS(RT)
HOPS(NRT)
HOPS(NRT)
HOPS(NRT)
HOPS(RT)
HOPS(RT)
HOPSid = 5
HOPSid = 10
FMCSid = 3
FMCSid = 40
ADJSid = 1
ADJSid = 2
ADJSid = 3
WCELWCELWCEL
WCEL
WCELWCELWCELWBTS
NrtFmcsIdentifier = 3
RtFmcsIdentifier = 40
NrtHopsIdentifier = 5RtHopsIdentifier = 10
Each WCEL has associated 1 FMCS for NRT & 1 for RT, both can be reused for other cells. Different FMCS’scould be defined for the different type of cells (urban, rural, macro/micro/pico)
Each ADJS has associated 1 HOPS for NRT & 1 for RT, both can be reused for other cells. Different HOPS’sparameters could be defined for the different type of cells (urban, rural, macro/micro/pico)
8 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
ADJS, HOPS & FMCSHO Parameter Categories
Intra-Frequency
Inter-Frequency
Inter-System
Handover Control ParametersRNC parametersWCEL parametersHOPS parameters FMCS parametersADJS parameters HOPI parameters FMCI parametersADJI parameters HOPG parameters FMCG parameters ADJG parameters
100HOPS parametersCell Re-selection HCS PriorityCell Re-selection HCS ThresholdCell Re-selection Minimum QualityCell Re-selection Minimum RX LevelCell Re-selection Penalty TimeCell Re-selection Quality Offset 1Cell Re-selection Quality Offset 2Cell Re-selection Temporary Offset 1Cell Re-selection Temporary Offset 2CPICH Ec/No Averaging WindowEnable Inter-RNC Soft HandoverEnable RRC Connection ReleaseHHO Margin for Average Ec/NoHHO Margin for Peak Ec/NoRelease Margin for Average Ec/NoRelease Margin for Peak Ec/No
Define Target Cell Selection
1100
FMCS parametersActive Set Weighting CoefficientAddition Reporting IntervalAddition TimeAddition WindowCPICH Ec/No Filter CoefficientCPICH Ec/No HHO CancellationCPICH Ec/No HHO Cancellation TimeCPICH Ec/No HHO ThresholdCPICH Ec/No HHO Time HysteresisCPICH RSCP HHO CancellationCPICH RSCP HHO Cancellation TimeCPICH RSCP HHO Filter CoefficientCPICH RSCP HHO ThresholdCPICH RSCP HHO Time HysteresisDrop TimeDrop WindowMaximum Active Set SizeReplacement Reporting IntervalReplacement TimeReplacement Window
Define Adjacent Cell Measurement Control
1
In GSM: Define HO TriggerHoThresholdsLevDL Rx (LDR): -92 dBm Px (LDP): 3 Nx (LDN): 4
Define Target Cell SelectionRx Lev Min Cell: -95 dBm
Define Adj Cell
31ADJS parameters Cell Identifier CPICH Ec/No Offset Disable Effect on Reporting Range Location Area Code Maximum UE TX Power on RACH Mobile Country Code Mobile Network Code Mobile Network Code LenPrimary CPICH power NRT HOPS Identifier Primary Scrambling Code RNC Identifier Routing Area Code RT HOPS Identifier Tx Diversity Indicator
Define Adj Cell
1
9 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Separate Handover Parameter Set (HOPS) identifiers for real time(RT) & non-real time(NRT) traffic
• RtHopsIdentifier - real time
• NrtHopsIdentifier - non-real time
• Each HOPS object is identified by a unique HOPSid (HOPS) in the RNC - on to which the RtHopsIdentifier and/or NrtHopsIdentifier parameters are mapped to identify the appropriate HOPS parameter set for that particular neighbor cell
• Primary scrambling code for neighbor cell specified using AdjsScrCode
• AdjsTxDiv specifies whether the neighbor cell is using Tx diversity
• AdjsTxPwrRACH determines the maximum power the UE can use on the PRACH when accessing the neighbor cell
Neighbour Cell Definition
10 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SHO: Neighbour Cell Definition• Each intra-frequency neighbor (ADJS) is identified using ADJSid (ADJS)
• The ADJS parameters provide information on the identity of each neighbor cell together with its properties (i.e. Handover parameter set identifier, scrambling code etc..)
• Each neighbor cell is defined using the UTRAN cell identifier which comprises
UTRAN Cell Identifier = MCC + MNC + RNC identifier + Cell identifierUTRAN Cell Identifier = MCC + MNC + RNC identifier + Cell identifier
• Each neighbor cell is defined using the UTRAN cell identifier which comprises;
MCC (Mobile Country Code) = AdjsMCCMNC (Mobile Network Code) = AdjsMNCRNC Identifier = AdjsRNCidCell Identifier = AdjsCI
• The LAC (AdjsLAC) & RAC (AdjsRAC) are also in ADJS parameter set
ADJS Parameters
11 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SHO: Neighbour Cell Definition
AdjsMCCAdjsMNCAdjsRNCidAdjsCI
UTRAN Cell ID
ADJSid
MaxActiveSetSizeRNCAdjsScrCodeAdjsTxDivAdjsTxPwrRACH
• RT HO Control Parameter: RtHopsIdentifier• NRT HO Control Parameter: NrtHopsIdentifier
12 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
13 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Soft Handover
• HC supports the following measurement reporting events:• Event 1A: A primary CPICH enters the reporting range (Ncell addition)
• Event 1B: A primary CPICH leaves the reporting range (Ncell deletion)
• Event 1C: A non-active CPICH becomes better than an active primary CPICH (Ncellreplacement)
• Cell individual offsets for modifying measurement reporting behaviour
• Mechanism for forbidding a neighbor ing cell to affect the reporting range
• Handover decision performed by RNC based on measurements and available resources
• Admission Control can reject the branch addition in case the maximum load is achieved in DL (threshold + offset), valid both for RT and NRT bitrates.
• Hard blocking may prevent branch addition
14 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• The Handover measurement is based on CPICH Ec/Io
• The accuracy of pilot Ec/Io measurements is important for Handover performance
• Measurement accuracy depends on the filtering length and mobile speed.• When a MS moves slowly or is stationary, filtering length (in ms) has to be just long enough to
avoid fast fades leading to errors and causing unnecessary Handovers within a short period.• Long filtering length will cause Handover delays to fast moving MS
• UE can perform averaging on EC/IO measurement prior to the event reporting process
• EcNoFilterCoefficient (FMCS) defines the measurement period for intra-frequency CPICH EC/IO measurements used by UE (default = 600ms). In the CELL_DCH state the UE physical layer measurement period for intra frequency CPICH Ec/No measurements is 200 ms. The Filter Coefficient parameter controls the higher layer filtering of physical layer CPICH Ec/No measurements before the event evaluation and measurement reporting is performed by the UE.
• RNC averages CPICH Ec/Io measurements using EcNoAveragingWindow (HOPS) - defines the number of event triggered periodic intra-frequency measurement reports used by RNC to calculate averaged CPICH EC/IO (default = 8 Measurements)
SHO: Measurement Control
15 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SHO: Measurement Control
Node B
UTRAN
RNCUE
Measurement Control [ ]
I am in the CELL_DCH sub-state
Measurement Type: Intra-frequency measurements• Reporting events:
1A: A primary CPICH enters the reporting range 1B: A primary CPICH leaves the reporting range 1C: A non-active CPICH becomes better than an active primary CPICH
• Event triggered / Periodical reporting • Measurement quantity: CPICH Ec/No• etc.
System Information [ ]
SIB 11/12• EcNoFilterCoefficient
Measurement accuracy depends on• speed &• Filter Coefficient
EcNoAveragingWindow
16 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1A: A Primary CPICH Enters the Reporting Range• Reporting range defined by offset (point 1 on next slide) from either
(i) best CPICH Ec/Io in the AS, or(ii) sum of the AS measurement resultsset using ActiveSetWeightingCoefficient (FMCS) (0 = use best CPICH : <>0 = use sum)
• Offset defined using AdditionWindow (FMCS)
• Event 1A triggered when CPICH3 Ec/Io enters UE reporting range (point 2)
• If CPICH3 Ec/Io remains within reporting range for a time period defined by AdditionTime (FMCS) , and the AS is not full, UE sends measurement report to RNC which adds Ncell3 to AS if possible (point 3)
• AdditionTime defines the 'time-to-trigger' interval between the Ncell first entering the reporting range and the UE sending the measurement report to the RNC
• If RNC is unable to add Ncell to AS, UE will wait for a period of time, defined by AdditionReportingInterval (FMCS) (point 4) after the first measurement report, before sending further reports periodically, with interval AdditionReportingInterval, until (a) Ncell moves out of reporting range, or (b) RNC adds Ncell to AS.
17 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
4
Strongest CPICH in AS
1A: A Primary CPICH Enters the Reporting Range
time
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2
1
2
3
AdditionWindow
AdditionTime
AdditionReportingInterval
RNC
MeasurementReport
Add tothe AS?
no
ActiveSetWeightingCoefficient
18 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Reporting criteria of event 1A in 25.331/RRC Measurement Control :
• Reporting Cell Status: All active cells + 2 monitored cells.
• Triggering Condition: Monitored Set cells
• Reporting Range Constant AdditionWindow / 4 dB
• Cells forbidden to affect Reporting range: AdjsDERR / Enable
• W: ActiveSetWeightingCoefficient / 0
• Time to trigger: AdditionTime / 0 = 0 ms
• Reporting deactivation threshold: MaxActiveSetSize = 3
• Amount of reporting: infinity
• Reporting interval: AdditionReportingInterval / O.5 s
1A: A Primary CPICH Enters the Reporting Range
19 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1A: A Primary CPICH Enters the Reporting Range
20 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1B: A Primary CPICH Leaves the Reporting Range
• Event 1B triggered when CPICH3 EC/I0 drops out of the UE reporting range for a defined period of time (point 1 on next slide)
• Reporting range = Strongest CPICH in AS - DropWindow (FMCS) (point 2)
• Time-to-trigger period set using DropTime (FMCS) (point 3)
• UE sends RNC measurement report on expiry of DropTime to remove Ncell (CPICH3) from AS.
• RNC drops the cell from the AS and UE drops the cell from the AS to the Neighbour Set
21 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Strongest CPICH in AS
time
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2
1
2
3
DropWindow
DropTime
MeasurementReport
1B: A Primary CPICH leaves the Reporting Range
Remove the reported cell from the AS
22 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Reporting criteria of event 1B in 25.331/RRC Measurement Control :
• Reporting cell Status: 3 active cells
• Triggering Condition: Active cells
• Reporting Range Constant: DropWindow / 4 dB
• Cells forbidden to affect Reporting range AdjsDERR / Enable
• W : ActiveSetWeightingCoefficient / 0
• Time to trigger: DropTime / 320 ms
1B: A Primary CPICH Leaves the Reporting Range
23 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1B: A Primary CPICH Leaves the Reporting Range
24 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Soft and Softer Handover (case1)
reportCriteria intraFreqReportingCriteria : {eventCriteriaList {{event e1a : {
triggeringCondition monitoredSetCellsOnly,reportingRange 4,w 0,reportDeactivationThreshold t2,reportingAmount ra-Infinity,reportingInterval ri0-5},hysteresis 0,timeToTrigger ttt100,reportingCellStatus allActiveplusMonitoredSet :
viactCellsPlus2}
event e1b : {triggeringCondition activeSetCellsOnly,reportingRange 6,w 0},hysteresis 0,timeToTrigger ttt640,reportingCellStatus withinActiveSet : e3},
• SIB 11 contains the relevant parameters to read when in idle mode
• These are valid in connected mode prior to receiving the measurement control that overwrites them
• In this example:• Addition window= 2 dB (factor of 2
mapping between the signalled value and the actual value, TS 25.331 defines this mapping)
• Addition time = 100 ms
• Reporting interval = 500 ms
• Drop window = 3 dB (factor of 2 mapping between the signalled value and the actual value)
• Drop time = 640 ms
Extract from SIB 11
25 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SIB11 length limitation• 3GPP has inconsistent requirements concerning the maximum number of neighbouring
cells that can be broadcasted in the SIB 11 and 12• SIB 11 and 12 can contain information on the maximum of 96 cells (32 intra-
frequency cells, 32 inter-frequency cells and 32 GSM cells)• On the other hand, the physical size of SIB data (no more than 3552 bits) has capacity
only for 47 cells!!
• If too many adjacencies are declared, the cell will go blocked by system with alarm: 7771 WCDMA CELL OUT OF USE (BCCH scheduling error) in RAN04
• As a rule of thumb, assuming that …
ADJS=15, ADJG=15, ADJI=15
… and “realistic worst case values”, SIB11 length = 3187.5 < 3552 -> OK!!
• Some sites might need additional neighbors and might pose a problem with the SIB11 limitation
• Avoid setting AdjsQoffset2 values, different CPICH values or other parameters used to tune cell reselection or handover
Further information Technical Note No. 046 / Restriction on number of cells in SIB11/12 due to inconsistency problem in 3GPP TS 25.331
26 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1C: A non-active CPICH becomes better than an active primary CPICH
• UE AS full (MaxActiveSetSize = 3)
• Event 1C triggered when CPICH4 EC/IO > CPICH3 in AS by a defined margin, ReplacementWindow (FMCS). (point 1 in next slide)
• Sending of measurement report to RNC can be delayed by using 'time-to-trigger' period set by ReplacementTime (FMCS)
• If 'time-to-trigger' is used difference between CPICH4 and CPICH3 must be ≥ReplacementWindow for the period of ReplacementTime (point 2)
• If the RNC is not able to replace the Ncells, the UE continues to send measurement reports periodically, with interval ReplacementReportingInterval, to the RNC until (a) CPICH4 falls out of ReplacementWindow or (b) RNC replaces CPICH4 by CPICH3 (point 3)
27 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
time
weakest CPICH3 in AS
Ec/Io
P CPICH 3
P CPICH 1P CPICH 2P CPICH 4
AS has 3 cells
ReplacementReportingInterval3
1
2
ReplacementWindow
ReplacementTime
MeasurementReport
RNC
ASupdate?
no
1C: A non-active CPICH becomes better than an active primary CPICH
28 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Reporting criteria of event 1C in 25.331/RRC Measurement Control :
• Reporting cell Status: All active cells + 2 monitored cells.
• Hysteresis: ReplacementWindow / 2 dB
• Time to trigger: ReplacementTime / 0 = 0 ms
• Replacement activation threshold : MaxActiveSetSize / 3
• Amount of reporting: infinity
• Reporting interval: ReplacementReportingInterval / 0.5s
1C: A non-active CPICH becomes better than an active primary CPICH
29 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1C: A non-active CPICH becomes better than an active primary CPICH
30 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Soft and Softer Handover (case 2)
event e1c : {replacementActivationThreshold t3,reportingAmount ra-Infinity,reportingInterval ri0-5},hysteresis 4,timeToTrigger ttt100,reportingCellStatus withinActiveSet : e3}
• In this example:• Replacement window = 1 dB
• Replacement time = 100 ms
• Reporting interval = 500 ms
• Replacement window requires mapping to its true value according to:
4/(2*2) = 1 dB
• There are two mappings – first is the signalled value to actual value mapping and second is the way in which hysteresis is applied in the event triggering equation (TS25.331)
• Once in connected mode the networks sends the same set of information elements via a measurement control message
• Nokia’s implementation is that the values in the measurement control message are the same as those within SIB 11
• Events 6F and 6G are configured in a similar fashion i.e. within SIB 11 and subsequently
Extract from SIB 11 cont.
with a measurement control message
31 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Individual Ncell Offset &Forbidding Neighbour Cell from Reporting Range
Individual Ncell Offset
• cell individual offsets for modifying measurement reporting behaviour
• effectively 'moves' cell border (shrinks or enlarges cell)
• offset set using AdjsEcNoOffset (= CPICH Ec/No Offset) (ADJS)
• offset applied to Primary CPICH measurements before event evaluation by the UE
Forbidding Neighbour Cells from Reporting Range
• the primary CPICH of certain cells can be forbidden from reporting range calculation in some instances
• cells can be forbidden from reporting range using AdjsDERR (ADJS)
32 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Individual Ncell Offset
time
P CPICH 1
P CPICH 2
P CPICH 3
Reporting Range
Reporting Event 1B
Reporting Event 1A
AdjsEcNoOffset
Artificially EnlargingCell 3 by x dB
Ec/Io
33 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Forbidding Neighbour Cell from Reporting Range
Time
P CPICH 1
P CPICH 2
P CPICH 3
PCPICH3 is forbidden to affect the reporting range as its quality is quite unstable.
Reporting Range
AdjsDERR
Ec/Io
34 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Event 1A(Add)
Event 1B(Drop)
Event 1C(Replace)
Active set cells +2 monitored set
cells
Monitored set cells
Addition Window/4 dB
Active set cells Active set cellsDrop Window/
6 dB
Active set cells +2 monitored set
cells- Replacement
Window/4 dB
Addition Time/0 ms
AdditionReportingInterval/0.5 s
Drop time/320 ms -
Replacementtime/0 ms
ReplacementReportingInterval/
1s
Event Reporting cell status
Triggering Condition
Reporting Range/Hysteresis Time to Trigger Reporting
Interval
• 3GPP reporting events 1A, 1B and 1C (also 6F and 6G)• CPICH Ec/Io is used as a measurement quantity rather than CPICH RSCP
• CPICH Ec/Io measurements are more accurate• 1A and 1B reporting range is defined by strongest active set cell• 1C reporting range is defined by weakest active set cell
SHO Summary
35 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• SHO for synchronisation reason:• Event 6F: The UE Rx-Tx time difference for a Radio Link (RL) included in the active set
becomes larger than an absolute threshold Reporting• Reporting event 6G: The UE Rx-Tx time difference for a RL included in the active set
becomes smaller than an absolute threshold
• Estimation of these events:• Based on UE Rx-Tx time difference
• Measurement configuration:• Time-to-trigger: not used.• 6F: UE Rx-Tx time difference threshold: UpperRxTxTimeDiffdefault: 1174 chips, range:1152 ... 1280 chips, step 1 chip
• 6G: UE Rx-Tx time difference threshold: LowerRxTxTimeDiffdefault: 874 chips range: 768 ... 896 chips, step 1 chip
• NOTE: Some UE does not support these events
UE Internal Measurements
36 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Node B
UTRAN
RNCUE
Measurement Control [ ] I am in the
CELL_DCH sub-state
Measurement Type: UE Internal measurements• Reporting events:
6F: The UE Rx-Tx time difference for a RL included in the active set becomes larger than an absolute threshold Reporting 6G: The UE Rx-Tx time difference for a RL included in the active set becomes smaller than an absolute threshold
DLnom
time
T0
UL DPCH
time
time
6F 6G
UE Internal Measurements
Question: what is the action after receiving MR e6f ?
37 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Measurement reporting criteria are cell specific
• Neighbouring cells (ADJS and HOPS parameters) are defined on a controlling cell (cell from which the call has been started or best cell in case the original cell has been deleted from the active set)
• During SHO the measurement reporting criteria are taken from the cell where the UE has started the connection
• The measurement reporting criteria are updated only when the Original (Reference) cellleaves the Active Set (Nokia Implementation), according to the strongest cell in the Active Set, by sending the MEASUREMENT CONTROL message, transmitted on the downlink DCCH. Standard would allow to update reporting criteria, according thecurrent best server.
• Note: When Reference cell (not always the best cell) leaves the Active Set, it could be easily identified since this is followed by UTRAN MOBILITY INFORMATION & UTRAN MOBILITY INFORMATION CONFIRM to indicate that AS Reference Cell has changed.
• When the UE receives a MEASUREMENT CONTROL message, the UE shall stop monitoring and measurement reporting and shall replace the measurement reporting criteria with the new information received in the MEASUREMENT CONTROL message.
Measurement Report Updating
38 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurements Reporting Criteria Updating during Soft Handover
Cell 1 Cell 2
•Neighbour ListCell1• Addition WindowCell1•Drop WindowCell1•Drop TimeCell1
1. Idle Mode
System Information
(BCCH)
BEST Server: Cell 1BEST Server: Cell 1
2. Connected Mode: Cell_DCH
The UE shall continue monitoring the list of neighboring cells assigned in System Information during Idle Mode
The UE shall continue monitoring the list of neighboring cells assigned in System Information during Idle Mode
Measurement Reporting Criteria according to Cell 1
Measurement Reporting Criteria according to Cell 1
The UE shall send the MEASUREMENT REPORT message when reporting
criteria are fulfilled.
The UE shall send the MEASUREMENT REPORT message when reporting
criteria are fulfilled.
Connected Mode: Cell_DCH
3. MEASUREMENT REPORT (DCCH)
Measurement Reporting Criteria according to Cell 1
Measurement Reporting Criteria according to Cell 1
Intra-frequency MeasurementIntra-frequency Measurement
The measurement reporting criteria are updated as soon as the original cell drops out from the Active Set (Nokia
Implementation).
The measurement reporting criteria are updated as soon as the original cell drops out from the Active Set (Nokia
Implementation).
Connected Mode: Cell_DCH
4. MEASUREMENT
CONTROL (DCCH)
•Neighbour ListCell2•Addition WindowCell2•Drop WindowCell2•Drop TimeCell2
BEST Server: Cell 2BEST Server: Cell 2
Measurement Reporting Criteria according to Cell 2
Measurement Reporting Criteria according to Cell 2
Reporting Criteria
Updating
39 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Neighbour List Measurement during SHO
Cell 1 Cell 2
Intra-frequency MeasurementIntra-frequency Measurement
•Addition WindowCell1•Drop WindowCell1•Drop TimeCell1
1. System Information (BCCH)
BEST Server: Cell 1BEST Server: Cell 1
Neighbour List Cell 1Neighbour List Cell 1
Measurement Reporting Criteria according to
Cell 1
Measurement Reporting Criteria according to
Cell 1
Active Set: Cell 1Active Set: Cell 1
2
3
5
2
3
5
3. MEASUREMENT REPORT (DCCH)
1A1B6. MEASUREMENT REPORT
(DCCH)
4. ACTIVE SET UPDATE
8. MEASUREMENT CONTROL (DCCH)
•Addition WindowCell2•Drop WindowCell2•Drop TimeCell2
BEST Server: Cell 2BEST Server: Cell 2
Measurement Reporting Criteria according to Cell 2Measurement Reporting
Criteria according to Cell 2
Neighbour List Update
1
3
4
1
3
4
Neighbour List Cell 2Neighbour List Cell 2
Active Set: Cell 2Active Set: Cell 2Meas. Rep.
Criteria Update
Measurement Reporting Criteria according to
Cell 1
Measurement Reporting Criteria according to
Cell 1
3
1
4
2
5
3
1
4
2
5
Neighbour List CombinationNeighbour List Combination
Neighbour List Update
5. MEASUREMENT CONTROL (DCCH)
Active Set: Cell1 - Cell2Active Set: Cell1 - Cell2
2. Setup Call
2. Setup Call
7. ACTIVE SET UPDATE
40 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• In Nokia RAN the measurement quantity for events 1A, B, C, E, F is P-CPICH Ec/No and for 1E,F also P-CPICH RSCP
• There are a huge number of intra-frequency measurement parameters.
• Please refer to the WCDMA Parameter Dictionary.
• See Measurement Control Parameter Set (FMCS object) which controls the intra-frequency measurements radio bearer, such as:
• 1A paramters:•ActiveSetWeightingCoefficient, AdditionReportingInterval, AdditionWindow, AdditionTime, MaxActiveSetSize, etc.
• 1B parameters:•ActiveSetWeightingCoefficient, DropTime, DropWindow, etc.
• 1C parameter:•MaxActiveSetSize, ReplacementReportingInterval, ReplacementTime, ReplacementWindow, etc.
• 1E parameter:•HHoEcNoCancel, HHoEcNoCancelTime, HHoRscpCancel, HHoRscpCancelTime, etc.
• 1F parameter:•HHoEcNoCancel, HHoEcNoTimeHysteresis, HHoRscpCancel, HHoRscpThreshold, HHoRscpTimeHysteresis, etc.
Nokia Parameters for Intra-Frequency Measurements
41 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• In the RRC idle state and in the RRC connected sub-states CELL_FACH, CELL_PCH and URA_PCH, the UE is responsible for cell selection and re-selection.
• It camps on one cell or it is served by one cell. • By reading the System Information Block 11 and/or 12, the UE gets the
•Intra-frequency cell info list,•Inter-frequency cell info list, and•Inter-RAT cell info list,•i.e. it gets several neighbourhood lists.
• In the CELL_DCH sub-state, the RNC must be able to continuously update the neighbour cell lists in order to reflect the changing neighbourhood of a moving mobile station.
• This is part of the RNC‘s handover control. • If we have more than one active set cell, which participate in a soft handover, the handover control
of the RNC is responsible to combine the lists into one neighbour cell list which is then transmitted to the mobile station.
• The neighbour cell list combination is carried out in the steps depicted in next slide.• A soft handover only takes place with cells on the same UTRA carrier band. Consequently, the
combining of neighbourhood lists of several active set cells is only required for intra-frequency handovers and has to combined with their measurements.
Neighbour Lists
42 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell 5 Cell 6 Cell 7 Cell 8
Cell 9 Cell 10 Cell 11 Cell 12
Cell 1 Cell 2 Cell 3 Cell 4
Neighbour List Cell 6:•Cell 2•Cell3•Cell 7
•Cell 11•Cell 10•Cell 5
Neighbour List Cell 7:•Cell 3•Cell4•Cell 8
•Cell 12•Cell 11•Cell 6
Cell 3Cell11
Cell 3Cell11
Neighbour cells which are common to Cell 6 and
Cell 7 Cell 4Cell 8
Cell 12Cell 6
Cell 4Cell 8
Cell 12Cell 6
Neighbour cells defined only for Cell 7
Cell 2Cell7
Cell 10Cell 5
Cell 2Cell7
Cell 10Cell 5
Neighbour cells defined only for Cell 6
Two Cells in the Active Set
Neighbourhood List Combination for Intra-frequency HOs
43 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell 2Cell 5Cell 7Cell 9
Cell 11Cell 15Cell 48Cell 4
Cell 41Cell 6
.....
Cell 43
Cell 2Cell 5Cell 7Cell 9
Cell 11Cell 15Cell 48Cell 4
Cell 41Cell 6
.....
Cell 43
Cell 15Cell 21Cell 2Cell 7
Cell 37Cell 51Cell 49Cell 9
Cell 10Cell 56
…...
Cell 25
Cell 15Cell 21Cell 2Cell 7
Cell 37Cell 51Cell 49Cell 9
Cell 10Cell 56
…...
Cell 25
Cell 1Cell 2Cell 3Cell 7
Cell 11Cell 50Cell 9
Cell 13Cell 10Cell 22
…...
Cell 33
Cell 1Cell 2Cell 3Cell 7
Cell 11Cell 50Cell 9
Cell 13Cell 10Cell 22
…...
Cell 33
Neighbour Cells Lists Step 1Step 1
Three Cells in the Active Set
Cell2Cell 7Cell 9
Cell2Cell 7Cell 9
Common to 3 Neighbour Lists
Step 2Step 2
Cell 11Cell 15Cell 10
Cell 11Cell 15Cell 10
Cell 37Cell 41Cell 49
…..…
Cell 22
Cell 37Cell 41Cell 49
…..…
Cell 22
Max 32 Cells
Neighbour Cells defined for only 1 Neighbourlist: best Ec/No first Step 4Step 4
Common to 2 Neighbour
Lists
Step 3Step 3
Neighbourhood List Combination for Intra-frequency HOs
44 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• The neighbourhood lists for intra-frequency handover measurements can be composed like this:• Step 1: Active set cells
•First the handover control sets the active set cells into the neighbour cell list.• Step 2: Neighbour cells which are common to three active set cells
•During the second step of neighbour cell list combination the handover control selects those neighbour cells which are common to all three active set cells. •If the total number of relevant neighbour cells exceeds the maximum number of 32 after the second step, the handover control removes in random order those surplus cells from the combined neighbour cell list which are selected during the second step
• Step 3: Neighbour cells which are common to two active set cells•During the third step of neighbour cell list combination the handover control selects those neighbour cells which are common to two active set cells. •If the total number of relevant neighbour cells exceeds the maximum number of 32 after the third step, the handover control removes in random order those surplus cells from the combined neighbour cell list which are selected during the third step.
• Step 4: Neighbour cells which are defined for only one active set cell•During the fourth step of neighbour cell list combination the handover control selects those neighbour cells which are defined for only one active set cell (random).•If the total number of relevant neighbour cells exceeds the maximum number of 32 after the fourth step, the handover control removes those surplus neighbours from the combined neighbour cell list which are selected during the fourth step, starting from the neighbours of the weakest (CPICH Ec/Io) active set cell.
Neighbourhood List Combination for Intra-frequency HOs
45 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Testing Details
06Mar29 adjs Ec_no offset update_in to outdoor--a lot round.rar
46 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjsEcNoOffset Testing Candidate Sites / Cells
1-way AdjsEcNoOffset = 6dB:13016 (36) 26016 (382) Rest = 0dB offset
1-way AdjsEcNoOffset = 6dB:13016 (36) 26016 (382) Rest = 0dB offset
• Testing sequence / scenario:
• 1-way AdjsEcNoOffset = 6dB defined between 11036 (36) 26016 (382). Rest of the ADJS = 0dB offset.
• UE initiate call under 16016 (374) with AS: SC374 as Reference Cell. MC indicates that SC382 (intraFreqCellID = 12) is without any AdjsEcNoOffset = 6dB
• UE moves towards 11036 (36), with SHO in between.
• When Reference cell change occurs; i.e. SC374 leaves the AS, SC36 became the newAS Reference Cell. (signified by UE receiving UMI & UMIC after MR e1b to remove Reference Cell from AS)
• DL sends MC to indicate new set of intra-frequency reporting criteria (e1a, e1b etc) ; as well as modify UE NB list; i.e. removing old NBs unique to SC374 & add new common NBs. Also, modify FreqCellID=12, SC382 with AdjsEcNoOffset=6dB.
• Individual Cell Offset works!!
47 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjsEcNoOffset Verification• RRC connection setup
on 16016 (374). SC374 is the Active Set (AS) Reference Cell.
48 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjsEcNoOffset Verification• RRC connection setup
on 16016 (374).
• Measurement Control sent indicating AS Reference Cell neighbour list.
• Note: intraFreqCellID = 12 SC382 has NO AdjsEcNoOffset defined.
49 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjsEcNoOffset Verification• RRC connection setup
on 16016 (374).
• Measurement Control sent indicating AS Reference Cell neighbour list.
• Note: intraFreqCellID = 12 SC382 has NO AdjsEcNoOffset defined.
• UE sends MR e1b to remove Reference Cell SC374 from AS.
• This is followed by UMI & UMIC to indicate that AS Reference Cell has changed (to SC36).
50 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjsEcNoOffset Verification• RRC connection setup on
16016 (374).
• Measurement Control sent indicating AS Reference Cell neighbour list.
• Note: intraFreqCellID = 12 SC382 has NO AdjsEcNoOffset defined.
• UE sends MR e1b to remove Reference Cell SC374 from AS.
• This is followed by UMI & UMIC to indicate that AS Reference Cell has changed (to SC36).
• DL sends MC (based on SC36) to indicate new set of intra-frequency reporting criteria (e1a, e1b etc). As well as modify UE NB list; i.e. removing old NBs unique to SC374 & add new common NBs.
• Note: Also, modify intraFreqCellID=12, SC382 with AdjsEcNoOffset=6dB (mapping IE x 2 12).
• Individual Cell Offset works!!
51 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Conclusion
52 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Conclusion of Parameter Verification:• Obviously the Individual Ncell individual offsets for modifying measurement reporting
behaviour works!! Else we would be in deep shit!! ;-)• However, based on the test scenario in this report, and Nokia Implementation**, it
should be noted that the Individual Cell Ec/No Offset definition or chaining between NCells would only come into effect IF the mutual cells became the AS Reference Cell with the old Reference Cell (who did not define AdjsEcNoOffset) removed.
• So, depending on the direction of drives, it may happen that in the case of some inconsistant drop calls along the highways or byways (with consistant deep fades due to physical structures obstruction etc) may still occur, although the individual cell EcNo offset was defined mutually between 1 pair of cells. Becos the AS Reference Cell was simply not changed in time to either of the supposedly chained pair of cells to modify the NB list to reflect the Ec/No Offset.
• For those serious and consistant drop call cases with the above symptom, on a case-by-case basis, it may be so that the possible solution is to define AdjsEcNoOffset to the earlier AS Reference Cell as well, which has NB definition both the supposedly chained pair of cells. (example to be included later, ZhongSan HW 6009U case)
• ** - The measurement reporting criteria are updated only when the original cell leaves the Active Set (Nokia Implementation), according to the strongest cell in the Active Set, by sending the MEASUREMENT CONTROL message, transmitted on the downlink DCCH. Standard would allow to update reporting criteria, according the current best server.
53 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
54 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• If RNC is not able to add (Event 1A) to or replace (Event 1C) an Ncell from the AS, UE sends periodic measurement reports (AdditionReportingInterval /ReplacementReportingInterval) until;
• Ncell is added/replaced in to AS• Ncell leaves reporting range• HO no longer required (e.g. different Ncell enters AS)
• RNC may not be able to add/replace Ncell due to (a) Iur congestion or (b) inter-RNC SHO is prevented due to setting of EnableInterRNCsho (HOPS) (Point 1 in next slide)
• If CPICH EC/NO of non-active Ncell continues to increase it will cause additional interference due to a non-optimal connection (point 2)
Hard Handover
55 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
HHO decision
• To avoid excessive uplink interference, RNC will perform an intra-frequency hard Handover if either of the following criteria are met
AveEcNoDownlink + HHoMarginForAveEcNo(n) < AvEcNoNcell(n)
EcNoDownlink + HHoMarginPeakEcNo(n) < EcNoNcell(n)
• AveEcNoDownlink and AvEcNoNcell(n) = measured values for the best AS cell and the nth NS cell, averaged over EcNoAveragingWindow measurements
• EcNoDownlink and EcNoNcell(n) = instantaneous values
• HHoMarginForAveEcNo (HOPS) = average Ec/N0 margin [-6 … 6]dB, default 1dB
• HHOMarginPeakEcNo (HOPS) = peak Ec/N0 margin [-6 … 6]dB, default 2dB
56 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Time
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2Reporting
range
AdditionReportingInterval
1
2
HHOMarginAverageEcNoHHOMarginPeakEcNo
1A (AdditionTime = 0)
AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcell
Hard Handover
3
57 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter-RNC intra-frequency Hard Handover(HHO)
• Intra-frequency hard handover is required to ensure handover between cells controlled by different RNCs when an inter-RNC Soft Handover is not possible
• No Iur between RNCs• Iur congestion or failure
• Intra-frequency hard Handover is lossless for NRT radio bearer but it causes short disconnection of RT radio bearer.
• Intra-frequency hard handover decisions made by the RNC are based on the intra-frequency measurement results, which are usually applied to the SHO procedure
• Also Enable Inter-RNC SHO parameter in intra-frequency HO path defines whether intra-frequency HO from the serving cell to a specified neighbour cells is performed as soft of hard
• Mobile evaluated Handover (MEHO)
CN
RNCRNC
Iu Iu
Iur
CN
RNCRNC
Iu Iu
Iur
58 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter-RNC intra-frequency Hard Handover (HHO)
• If RNC is not able to add (Event 1A) to or replace (Event 1C) an Ncell from the AS, UE sends periodic measurement reports (AdditionReportingInterval/ ReplacementReportingInterval) until;
• Ncell is added/replaced in to AS• Ncell leaves reporting range• HO no longer required (e.g. different Ncell enters AS)
• RNC may not be able to add/replace Ncell due to (a) Iur congestion or (b) inter-RNC SHO is prevented due to setting of EnableInterRNCsho (HOPS) (point1 on next slide)
• If CPICH EC/NO of non-active Ncell continues to increase it will cause additional interference due to a non-optimal connection (point 2)
• To avoid excessive uplink interference, RNC will perform an intra-frequency hard handover to the Ncell (CPICH3) if either of the following criteria are met (point 3);
AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcell
EcNoDownlink + HHOMarginPeakEcNo < EcNONcell
Parameters :
• Enable Inter-RNC Soft Handover ( YES/NO, default = YES )
• HHO margin for Peak EcNo (-6…6 dB, default =2 dB)
• HH Margin for Average EcNo (-6…6 dB, default=1 dB)
59 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Time
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2Reporting
range
AdditionReportingInterval
1
2
HHOMarginAverageEcNoHHOMarginPeakEcNo
1A (AdditionTime = 0)
AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcellAveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcell
3
Inter-RNC intra-frequency Hard Handover (HHO)
60 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Case #1-1 – Inter-RNC, Intra-Frequency Hardhandover (HHO)
TMSI 00 01 86 55
RNTI RN26:00 57 8 (= 1400)
RN27: 02 2E 6 (= 8934)
Time_orig 15:21:45.882
RNC_orig / CID (SC) RN26 / 22952 (258)
RNC_End / CID (SC) RN27 / 32242 (264)
• Handover Category:
• Iur Failure - Inter-RNC SRNC Relocation failure => Triggering Inter-RNC, Intra-Frequency HHO.
• Analysis:
• Iur failure was simulated / purposely disabled via blocking AAL2 User Plane, to invoke Inter-RNC, Intra-Frequency HHO.
• Solution / Action proposed:ScannerScanner
UE RSCPUE RSCP
UE Ec/NoUE Ec/No
RNTI_00000578_0157.zip
RNTI_000022E6_03EF.zip
RN26RN26
RN27RN27
Iur Failure !Iur Failure !
61 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Case #1-2 – Inter-RNC, Intra-Frequency Hardhandover (HHO)
TMSI 00 01 86 55
RNTI RN26:00 57 8 (= 1400)
RN27: 02 2E 6 (= 8934)
Time_orig 15:21:45.882
RNC_orig / CID (SC) RN26 / 22952 (258)
RNC_End / CID (SC) RN27 / 32242 (264)
• Handover Category:
• Iur Failure - Inter-RNC SRNC Relocation failure => Triggering Inter-RNC, Intra-Frequency HHO.
• Analysis:
• Iur failure was simulated / purposely disabled via blocking AAL2 User Plane, to invoke Inter-RNC, Intra-Frequency HHO.
• Solution / Action proposed:ScannerScanner
UE RSCPUE RSCP
UE Ec/NoUE Ec/No
RN26RN26
RN27RN27
62 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• If difference between the best AS cell and the NS cell is too high and SHO is not performed, the RRC connection is released to avoid excessive interference
• Why might an AS update not be possible?• Excessive load in the neighbor ing cell• Hard blocking in the target BTS• Unavailability of DL spreading codes• Iub transport resources unavailable
• This function is activated by EnableRRCRelease (HOPS parameter)/0=no (def),1 =yes
• The RRC connection is released if either:
AveEcNoDownlink + ReleaseMarginForAveEcNo(n) < AvEcNoNcell(n)EcNoDownlink + ReleaseMarginPeakEcNo(n) < EcNoNcell(n)
• ReleaseMarginForAveEcNo (HOPS) = average Eb/N0 margin [-6 … 6] dB, default 2.5dB• ReleaseMarginPeakEcNo (HOPS) = peak Eb/N0 margin [-6 … 6] dB, default 3.5dB
• Emergency calls are exempt from RRC Connection Release process
RRC Connection Release
63 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
64 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Traffic Balancing
• Traffic balancing with Call setup control or during hard HO to another frequency
• Directed RRC connection setup => direct the user to the frequency with lower loading within the same sector
• A second frequency can be added for each sector/site independently as the capacity needs to be increased
f1f1 f1f1 f1f1
f2f2
f2f2 f1f1 f1f1
High capacity site
Start call on f2 Coverage reasonHandover
High capacity WCDMA sites can be utilized with RAN1.5
High capacity WCDMA sites can be utilized with RAN1.5
65 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Directed RRC Connection Setup
If either the UL or DL load of the Source cell exceed a certain threshold value, the DRRC Connection setup process is initiated.
• CurrentCellPrxTotal > PrxTarget (default 4 dB)+ DRRCprxOffset (default -1 dB)• CurrentCellPtxTotal > PtxTarget (def. max-3 dB)+ DRRCptxOffset (default -3 dB)
• The load of the current cell (UL/DL) is compared with the load of other cells in same sector to find out cell having less load:
• CurrentCellPrxTotal > CellPrxTotal(n) - DRRCprxMargin(default -0.5 dB)• CurrentCellPtxTotal > CellPtxTotal(n) - DRRCptxMargin(default -2 dB)
• Decision of Directed RRC connection setup is done by Admission Control in RNC
• Directed RRC connection setup is used for balancing the load (UL/DL) between cells which belong to same sector
• Same sector has cells with equal primary CPICHpower, PtxTarget, PtxOffset, PrxTarget and PrxOffsetvalues
• Parameter Sector Identifier tells to which sector cellbelongs to
66 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Site – Sector – Cell in 3G
f 1
1+1+1
2+2+2
f 1 f 2
Each WCDMA cell consits of:Load Control (LC)Admission Control (AC)Packet Scheduler (PS) / HSDPA
3 cells covering 3 sectors. 6 cells covering 3 sectors.
Sector 1
Sector 2
Sector 3
Cell 1
Cell 2Cell 3
Site „Bonn 77“
1 site (NodeB, WBTS) with 3 cells.
high capacity-site „Bonn 99“
1 site (NodeB, WBTS) with 6 cells.
Sector is meant as geographical coverage area
Cell 1
Cell 2Cell 3
Cell 4
Cell 5
Cell 6
Sector 3Sector 2
Sector 1
67 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
RACH: RRC Connection Setup Request
Cell_2 frequency 2
Cell_1 frequency 1
FACH: RRC Connection Setup
DCCH: RRC Connection Setup Complete
Cell_1 load > Cell_2 load + load threshold-> DRRC activated
Directed RRC Connection Setup - Signalling
incl. UARFCN of target cell
68 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Technical Background – DRRC (2)
Load of Source cell Load of Target cell
0 %
60 %
NoDRRCallowed
PrxTarget PtxTarget
DRRCprxOffset (-1 dB) DRRCptxOffset (-3 dB)
0 %
60 %
DRRCprxMargin (0dB) DRRCptxMargin (-0.5 dB)
DRRCNoDRRCneeded
CurrentCellPrxTotalCurrentCellPtxTotal
PrxTargetPtxTarget
CellPrxTotal(n)CellPtxTotal(n)
DRRC
DRRC connectionsetup
DRRC connection setup to the target cell if both of the following equations are fulfilled:CurrentCellPrxTotal (source cell) > CellPrxTotal(n) – DRRCprxMargin (default 0dB)
CurrentCellPtxTotal (source cell) > CellPtxTotal(n) – DRRCptxMargin (default –0.5dB).
If either the UL or DL load of the Source cell exceed a certain threshold value, the DRRC Connection setup process is initiated.
CurrentCellPrxTotal(s) > PrxTarget(s) + DRRCprxOffset (default –1dB)CurrentCellPtxTotal(s) > PtxTarget(s) + DRRCptxOffset (default –3dB)
69 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Basic 2nd Carrier & DRRC Parameter Settings (Example)Parameter 1st Carrier 2nd Carrier Remark
LCR ID 1,2,3 4,5,6Ptx_CPICH 33 dBm 33 dBm Cell specific. Carrier 1 & 2 must
have same value.Ptx_Target 42 dBm 42 dBm Cell specific. Carrier 1 & 2 must
have same value.Ptx_Offset 1 dB 1 dB Cell specific. Carrier 1 & 2 must
have same value.Prx_Target 30 dB 30dB Cell specific. Carrier 1 & 2 must
have same value.Prx_Offset 1 dB 1 dB Cell specific. Carrier 1 & 2 must
have same value.Sector ID As defined As defined Carrier 1 & 2 must have same
value/ sector.DRRCptxOffset - 3 dB - 3 dBDRRCptxMargin -0.5dB -0.5 dBDRRCprxOffset -1 dB -1 dBDRRCprxMargin 0 dB 0 dB
*FMCS 7 / 8HHoRscpThreshold: -95dBmHHoRscpCancel:-92dBm*FMCI 1 / 1IFHO caused by CPICH RSCP:used
GSM HO caused by CPICH RSCP:not used
Minimum Required quality level -20 dB -20 dBMinimum Required RX level -115 dBm -90 dBmSintrasearch On/12 off Off:always measureSintersearch On/2 off Off:always measureSsearchRAT On/4 On/4
FMCG (RT/NRT) 1 / 11 NA
FMCS (RT/NRT) 2 / 12 7 / 8
FMCI (RT/NRT) 1 / 11 1 / 1
These parameters MUST BE the same for cells defined as same Sector, in order for DRRC functionality to work.
These parameters MUST BE the same for cells defined as same Sector, in order for DRRC functionality to work.
70 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
71 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Compressed Mode in UplinkGSM BTS WCDMA BTS
DL
DL CM (this should be offwhen GSM is measured)
UL CM (needed to avoid interference)
During WCDMA transmissionsignal leakage will go to GSMRx also
72 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Compressed Mode (CM)• CM was introduced to WCDMA to allow inter-frequency (system) Handovers• CM is used to create idle periods (gaps) in the transmission during which ncell measurements on
another frequency can be made
• The reception/transmission gap is always seven slots in RN2.0. Gaps can be created using single or double frame approach (Nokia supports both)
• Because same data amount is sent in a shorter time more power is needed during CM (both in UE and BTS)
=> affects WCDMA coverage
• Fast Power control information might be lost during the gap => higher Eb/No=> affects WCDMA capacity
• Compressed frames may be lost if power control is not set correctly=> affects WCDMA quality
• CM methods are Spreading Factor Halving and Higher Layer Scheduling (both supported in RN2.0)
Normal frame Normal frame
Measurement gapMeasurement gapPower / Data Rate
CompressedMode
Normal frame
73 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Gap
Min transmitted TSs per Frame: ≥ 8
radio frame radio frame
TGL
Length of gap:3, 4, 5, 7 timeslots
Single-frame method
radio frame radio frame
TGL
Double-frame method
Length of gap:3, 4, 5, 7, 10, or 14 timeslots
The reception/transmission gap is always 7 time slots in RN2.0.
The reception/transmission gap is always 7 time slots in RN2.0.
74 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Gap
75 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Compressed mode methods • Halving Spreading Factor, SF/2 for RT and NRT services (UL
and DL)• Doubles temporarily the physical channel data rate, possible for all services• Needs 3 dB more UE power due to halved spreading ratio • If new channelization code is available from code tree in DL
• WCEL: AltScramblingCodeCM/0=used (def), 1=not used
• Higher Layer Scheduling, HLS (UL and DL) • Only possible for PS services (RT or NRT)• Does not cause extra load to the cell but reduces DCH user data• HLS ¾ data rate or HLS ½ data rate possible
Double frame is used in case of HLS ¾ data rateSingle frame is used in case of spreading factor halving and HLS ½ data rate.
76 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Compressed mode parameters
• CM can be activated/deactivated by CMmasterSwitch (RNC) /0=in use (def)
• HLS rate configurable using HLSModeSelection (RNC)/def 0=1/2 HSL , 1=3/4 HSL
• Maximum number of UEs in CM is controlled through MaxNumbUECMcoverHO (RNC)/16 (range 0..255)
• The number of UEs in DL CM depends on the PtxTotal value• The number of UEs in UL CM depends on the PrxTotal value
77 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
How many UEs in Compressed Mode ?
PtxTarget/PrxTarget
DL/ULtransmission power
Load
PtxOffset/PrxOffset
New UEs can be switched to CM when:Pxx_Total < Pxx_Target &
# of UEs in CM < MaxNumbUECMcoverHO
One new UE in CM can be allowedif the limit is not reached
No new UE can be in CM here
78 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AMR, RT PS or CS data serviceAMR, RT PS or CS data service
SF/2 used for both UL and DL
• Selection of the compressed mode method is performed in the following way:
SF/2 used for both UL and DL •compressed mode trigger parameters have to be set so that there is room for power increase due to code splitting otherwise power increase is cut and quality of connection gets worse during the compressed frames•Usage of alternative scrambling code is possible if RNP parameter AltScramblingCodeCM enables
Transmission Gap Pattern:Single frame: 7 slot gap,
variable # of normal frames
Transmission Gap Pattern:Single frame: 7 slot gap,
variable # of normal frames
NRT PS data serviceNRT PS data service
Higher layer scheduling is usedfor both UL and DL
Higher layer scheduling is usedfor both UL and DL
Transmission Gap Pattern:Transmission Gap Pattern:
Single frame: 7 slot gap,# of normal frames
Single frame: 7 slot gap,# of normal frames
Double frame: 7 slot gap,# of normal frames
Double frame: 7 slot gap,# of normal frames
Selection between HLS ½ and HLS ¾
Selection between HLS ½ and HLS ¾
Compressed Mode Initiate Compressed Mode
Configure GSM measurements
79 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Multi Service : AMR + PS data, AMR + CS data,
PS data + CS data
Multi Service : AMR + PS data, AMR + CS data,
PS data + CS data
SF/2 used for both UL and DL
• Selection of the compressed mode method is performed in the following way:
SF/2 used for both UL and DL•also same power and alternative scrambling code aspects as in pure AMR or CS data service cases
Transmission Gap Pattern:Single frame: 7 slot gap,
variable # of normal frames
Transmission Gap Pattern:Single frame: 7 slot gap,
variable # of normal frames
• Note that same method according to service is used for all Handover triggers• Both uplink and downlink gap patterns can be used despite of whether other direction is compressed or not
• If both directions (UL and DL) are compressed, gap pattern is chosen so that both directions support it• E.g. downlink support single frame but uplink double frame, it means that double frame shall be used
• The number of normal frames between gapped frames is defined with parameters• This solution leaves the following problem in certain multi service call
• Currently UEs of certain vendor do not support in downlink DPCCH and DPDCH slot format #15B (compressed mode code splitting when SF=4)
• This means that 320 kbps PS data + AMR does not work for these terminals • This problem can be partly avoided by denying compressed mode with that high data rate
• It can be done in downlink with RNP parameter HHOMaxAllowedBitRateDL
Compressed Mode Initiate Compressed Mode
Configure GSM measurements
80 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Compressed mode
• The normal compressed mode strategy includes fewer combinations of compressed mode configurations
• The non-configurable RNC parameter CompressedModeStrategy is used to select between the two strategies
• This parameter is configured to apply the normal strategy
• The normal strategy has been selected to minimise system complexity while the quantity of field experience is relatively low
CM Method SF/2AMR Speech RT Data
SF/2NRT Data
½ or ¾ Rate HLS
81 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
82 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
IFHO/ISHO Process Overview
HO Triggering Thresholds set in RNCHO Triggering Thresholds set in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
RNC commands selected UE(s) to startIF/IS measurements
RNC commands selected UE(s) to startIF/IS measurements
Measurements are done in Compressed Mode (CM)
Measurements are done in Compressed Mode (CM)
UE reports GSM cells withstrongest RSSI signals to RNCUE reports GSM cells with
strongest RSSI signals to RNC
RNC makes HO decision andcommands UE to target cell
RNC makes HO decision andcommands UE to target cell
RSSI measurements and BSICverification for GSM cells
RSSI measurements and BSICverification for GSM cells
Different decision methods for IF HOOnly one decision method for IS HO
5 Coverage/Capacity HO Reasons
About 25 HO parameters
Reporting cells are active set cells (max 3) + max 6 IFHO, max 6 ISHO neighb.
Max 32 neighbor s could be measured
(31 Intra-Freq neighbor s)48 Inter-Freq neighbor s 32 Inter-System neighbor s can be measured
83 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
IFHO/ISHO measurements- difference• IF measurements
• IS measurements
• BSIC verification required in case neighbor list includes multiple GSM neighbor s using the same RF carrier
WCDMA
IS-HOMeasurement
Trigger Target Cell found
RSSI meas. BSIC verification
IS-HODecision
WCDMA
IF-HOMeasurement
TriggerTarget Cell found
IF -measurements
IF-HODecision
84 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
85 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
IF/IS Handover Triggering Reasons
4. DL DPCH approaches itsmaximum allowed powerFMCI: IFHOcauseTxPwrDLFMCG: GSMcauseTxPwrDL
5. Quality deterioration report from UL outer loop PCFMCI: IFHOcauseUplinkQualityFMCG: GSMcauseUplinkQuality
3. UE Tx power approaches itsmaximum allowed power, event 6A/6DFMCI: IFHOcauseTxPwrULFMCG: GSMcauseTxPwrUL
2 . Low measured absoluteCPICH RSCP, events 1E/1FFMCI: IFHOcauseCPICHrscp, FMCG: GSMcauseCPICHrscp
1. Low measured absolute CPICH Ec/No, event 1E/1FFMCI: IFHOcauseCPICHEcNoFMCG: GSMcauseCPICHEcNo
HO trigger
6 . Others (Not implemented in RAN 1.5):e.g. Traffic & load reason IS-HO, etc
Frequency Measuring Control for Inter-Frequency = FMCIFrequency Measuring Control for Inter-System (GSM) = FMCG
86 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1. Measurement trigger CPICH Ec/NoReporting event: 1E: A P-CPICH exceeds an absolute threshold (triggered if one)
1F: A P-CPICH falls below an absolute threshold (triggered if all)
time
Cell 1 Cell 2
Cell 3
absolutethreshold
e.g.
P-C
PICH
Ec/
No
1E: HHoEcNoCancel
1E: HHoEcNoCancelTime
1F: HHoEcNoThreshold
1F: HHoEcNoTimeHysteresis
87 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
1. Measurement trigger CPICH Ec/No
• RNC starts IF/IS measurement when event 1F occurs for all cells in the active set: A Primary CPICH becomes less than an absolute threshold
• RNC stops IF/IS measurement when event 1E occurs for at least one cell of the active set : A Primary CPICH becomes better than an absolute threshold
• Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasIntervalGsmMinMeasInterval/default 10s, recommendation 2s .
• Filtering applied before event evaluation in the UE:• FMCS: EcNoFilterCoefficient/0= 200ms filtering period
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1. Measurement trigger CPICH Ec/No• Event 1E parameters:
• Triggering conditions: Active set cells• Hysteresis: not used in 1F• Threshold used frequency: FMCS : HHoEcNoCancel/ -20 dB• Time-to-trigger: FMCS: HHoEcNoCancelTime/ 1280 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells
• Event 1F parameters:• Triggering conditions: Active set cells• hysteresis: not used in 1F• Threshold used frequency: FMCS : HHoEcNoThreshold / - 22 dB (range 0..-24 dB)• Time-to-trigger: FMCS: HHoEcNoTimeHysteresis / 640 ms (range 0..5000ms)• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells
89 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
2. Measurement trigger CPICH RSCP
• UE continually monitors pilot channels of BTSs in AS
• If RSCP of a Node B falls below threshold, HHoRscpThreshold, UE sends event 1F report
• RNC starts IF/IS measurements when event 1F occurs for all cells in AS
• RNC stops IF/IS measurements when event 1E occurs for at least one cell of AS
• Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasIntervalGsmMinMeasInterval/default 10s, recommendation 2s .
• UE filtering applied before event evaluation using HHoRscpFilterCoefficient (FMCS) /200ms, range 200…1600ms
90 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
2. Measurement trigger CPICH RSCP• Event 1E (A primary CPICH exceeds an absolute threshold) parameters:
• Triggering conditions: Active set cells• hysteresis: not used in 1E• Threshold used frequency: (FMCS) : HHoRscpCancel/ - 100 dBm• Time-to-trigger: (FMCS): HHoRscpCancelTime/ 1280 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells
• Event 1F (A primary CPICH falls below an absolute threshold) parameters:• Triggering conditions: Active set cells• Hysteresis: not used in 1F• Threshold used frequency: HHoRscpThreshold (FMCS)/ - 105 dBm• Time-to-trigger: HHoRscpTimeHysteresis (FMCS)/ 640 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells
91 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Reporting Events 6A, 6B and 6D
timetime totrigger
UE T
xPo
wer
UE Transmitted Power Tx Threshold
6B6A
6Dmin(UEtxPowerMaxDPCH, P_MAX)
6A: The UE Tx power exceeds an absolute threshold 6B: The UE Tx power falls below an absolute threshold 6D: The UE Tx power reaches its maximum value
InterfreqUETxPwrTimeHystGSMUETxPwrTimeHyst
92 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
3. Measurement trigger UE Tx Pw (UL Coverage)
• RNC orders IF/IS measurements when one of the following event occurs:• Event 6A: The UE Tx power becomes larger than an absolute threshold• Event 6D: The UE Tx power reaches its maximum value
• Also GSM measurements could be measured first depending on UE Tx power values in IFHO and ISHO parameters
• Only lower threshold is send to UE, so either WCDMA or GSM is measured first, but also other RAT could be measured if not good enough neighbor is found
• In addition, the UL data rate allocated to the user must not exceed WCEL: HHoMaxAllowedBitrateUL/32 kbits/s
• RNC calls off inter-frequency measurements when event 6B occurs: the UE Tx power becomes less than an absolute threshold.
• Filtering applied before event evaluation in the UE.• FMCI : InterfreqUETxPwrFilterCoeff/8=10ms (range 10..480ms)• FMCG: GSMUETxPwrFilterCoeff/8 =10ms (range 10..480ms)
• NOTE: Not all UE vendors support 6A event
93 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
3. Measurement trigger UE Tx Pw (UL Coverage)• Event 6A parameters:
• Time-to-trigger: 0s• UE Transmitted Power threshold = min (UEtxPowerMaxDPCH, Pmax) –
UE_TX_POWER_threshold• UEtxPowerMaxDPCH is the maximum allowed UL tx power on DPCH in the active
cell (range -50..24 dBm, step 1, default 21 dBm), Pmax is the maximum RF output power
• UE_TX_POWER_Threshold depends on the type of service:• FMCI: InterfreqUETxPwrThrAMR/-3 dB (range -10..0, step1)• FMCI: InterfreqUETxPwrThrCS/-3 dB (same range and step)• FMCI: InterfreqUETxPwrThrNrtPS/-3 dB • FMCI: InterfreqUETxPwrThrRtPS/-3 dB • FMCG: GSMUETxPwrThrAMR/CS/NrtPS/RtPS -1/-3/-1/-3/ dB
• Event 6B parameters: time-to-trigger• FMCI: InterfreqUETxPwrTimeHyst/1280 ms • FMCG: GSMUETxPwrTimeHyst/1280 ms
• Event 6D parameter: time-to-trigger: 0s
94 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
DL_code_PWR > Ptx_RL_max + DL_DPCH_TXPWR_Thresholdexample: -100dBm > 33dBm+XXX+(-1dB)
4. Measurement trigger DL DPCH (DL Coverage)• RNC orders UE to make IF/IS measurements when DL TX power of a single radio link reaches threshold
defined as:
NOTE: Either WCDMA or GSM will be measured, not both systems
• DL_CODE_PWR = measured DL code power
• Ptx_RL_max = CPICH Pwr + MAX_DL_DPCH_ TXPWR• CPICH Pwr = Tx power of the CPICH of an active cell. PtxPrimaryCPICH (serving RNC) or
AdjsCPICHTxPwr (drifting RNC)/33 dBm, range -10…50 dBm, step 0.1 dBm• MAX_DL_DPCH_TXPWR = maximum transmission power level of the DPDCH symbols a
base station can use on the DPCH, expressed as a relative value to the CPICH pw
• DL_DPCH_TXPWR_Threshold = depends on the service type• FMCI: InterfreqDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB (range -10 dB..0, step 0.5
dB)• FMCG: GSMDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB (range -10 dB..0, step 0.5 dB)
• In Addition, the DL data rate allocated to the user must not exceed• WCEL: HHoMaxAllowedBitrateDL
95 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
4. Measurement trigger DL DPCH (DL Coverage)
Node BRNC
DCH Data Frame
IubUE
PO1TPC
Pilotbits not used
TFCIData 2 bitsData 1 bits
PO2DL_CODE_PWR
≥ Ptx_RL_max+ DL_DPCH_TXPWR_THRESHOLD
Max Power on DPCH (e.g. 33 dBm)
Serving WCDMA cell
time
It‘s time to triggerHO measurements
in the UE
e.g. Radio Link Measurement Report(e.g. Transmitted Code Power Value)
HHoMaxAllowedBitrateDL
Example Speech:Power Data Bits > 33dBm + (-3dB) + (-1dB)
Power Data Bits > 29 dBm (~1W)
Max Power on Channel
96 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
5. Measurement trigger UL Quality
• RNC starts IF/IS measurements based on UL outer-loop power control reports (see Module 3 Outer-loop PC)
• Enable reports from Outer-loop Power Control Controller to trigger IF/IS HO, RNC: EnableULQualDetRep/default 0=no, 1=yes
• Time duration for which BER/BLER target has not been reached, despite SIR target at maximum level, RNC: ULQualDetRepThreshold/0.5 s, 0.5..5, step 0.5s
• Periodic report, every RNC: ULQualDetRepThreshold seconds, while BLER/BLER target is not reached
• In addition, the UL data rate allocated to the user must not exceed WCEL: HHoMaxAllowedBitrateUL (default value: 32 kbits/s)
See Module 3 Channels & PowerControlSee Module 3 Channels & PowerControl
97 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
5. Measurement trigger UL QualityTa
rget
SIR
Max SIR target
Min SIR target
Actual SIR target
1st Quality deterioration report from PC to HC inside RNC
2nd Quality deterioration report (while the condition issatisfied the message is periodically repeated)
default 0.5s time
ΔSIRΔSIR
RNC
ULQualDetRepThreshold (recommendation 0.5s)
EnableULQualDetRepHHoMaxAllowedBitrateUL
RNC
98 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
99 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Decision Algorithm
UE Tx Power (Event 6A\6B)•Threshold:InterFreqUETxPwrThrXX•L3 filter:InterFreqUETxPwrFilterCoeff *•Hysteresis margin (time to trigger):InterFreqUETxPwrTimeHyst *•Data rate thresholdHHOMAxAllowedBitrateUL *
UL Quality•Timer:ULQualDetRepThreshold•Data rate thresholdHHOMAxAllowedBitrateUL
DL DPCH power•Threshold:InterFreqDLTxPwrThrXX
•Data rate thresholdHHOMAxAllowedBitrateDL
(XX=AMR,NrtPS,RtPS)
CPICH RSCP (Event 1F)•Thresholds:HHoRscpThresholdHHoRscpCancel•L3 filter:HHoRscpFilterCoefficient *•Time to trigger:HHoRscpTimeHysteresis *HHoRscpCancelTime *
CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:EcNoFilterCoefficient *•Time to trigger:HHoEcNoTimeHysteresis *HHoEcNoCancelTime *
AdjiPlossMarginAdjiMinEcNoAdjiMinRSCPAdjiTxPwrDPCHAdjiEcNoMargin
InterFreqMaxMeasPeriod *InterFreqMeasRepInterval *InterFreqNcellSearchPeriod * InterFreqMinHoInterval *InterFreqMinMeasInterval * InterFreqMeasAveWindow *
Handover Triggering
Handover Execution
IF HO meas control parameters
(* = parameters already optimised)
IF HO Parameters
(in blue = parameters under study)
1 more IFHO triggers in RAN04:
• IMSI basedIFHO
100 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
IFHO measurements• After HO triggering message is sent to RNC, a RRC message ”Measurement Control” is
sent to UE containing details of the measurement that the UE must execute. Measurement reporting is periodical. Max 6 IF cells can be reported. No filtering in measurements by UE.
• Upon reception of the measurements reported by the UE, RNC applies a sliding averaging window to the CPICH Ec/No & CPICH RSCP measurements. The averaged levels are used as input to the inter-frequency decision algorithm.
• From each cell in active set (max=3) also intra-frequency measurements are done at same time
RNCRRC: ”Measurement control ” message
("carrier 2" measurements)
UE
RNC
CPICH Ec/No and CPICH RSCP measurements are reported through ”Measurement report” messages
UE
RRC: ”Measurement report”
RRC: ”Measurement report”
In one measurement report there is both intra-and inter-frequency
results, no measurement filtering is used in UEAdjiMeasRepInterval
(default 0.5s)
3 neighbor info send to UE:UTRA RF channel, cell
individual offset (Ec/No) and primary scrambling code
101 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Control Parameters: FMCI
• InterFreqMeasRepInterval: 0.5 seconds• This is the interval between measurement reports, which are sent to BTS
• InterFreqMinMeasInterval:10 s• This is Minimum Measurement Interval, wait time when the following CM starts,
In case of an unsuccessful IFHO attempt, the network will deactivate compressed mode for a time period given by this parameter, thus better value will be 2 s to speed up the reactivation of CM.
• InterFreqMeasAveWindow: 6• This is Measurement Averaging Window size, sliding window is used
• InterFreqMaxMeasPeriod: 20 reports• This is Maximum Measurement Period which determines the maximum allowed
duration of the inter-frequency measurement• If the RNC is not able to execute an inter-frequency Handover, it shall stop the
inter-frequency measurements after the UE has sent the predefined number of measurement reports to the RNC.
102 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Control Parameters: FMCI• Maximum allowed duration of the inter-frequency measurement is calculated:
• InterFreqMeasRepInterval * InterFreqMaxMeasPeriod (0.5*20s) =10s,
• This seems to be too long time, because CM time was noticed to be about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if there is failure, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IFHO attempt. Proposed value for GSMMaxMeasPeriod is 6
• This seems to be too long time, because the CM time was noticed to be about 3 s, thus proposed value for InterFreqMaxMeasPeriod is 6
• InterFreqNcellSearchPeriod:0 • This is neighbor cell search period parameter, IFHO is not allowed until the are
enough measurement reports given by this parameter• O means that only 1 measurement result is enough for decision making• Duration of the cell search period is calculated:
InterFreqMeasRepInterval * InterFreqNcellSearchPeriod).
103 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Decision Algorithm
UE Tx Power (Event 6A)•Threshold:GsmUETxPwrThrXX•L3 filter:GsmUETxPwrFilterCoeff•Hysteresis margin:GsmUETxPwrTimeHyst•Data rate threshold
HHOMAxAllowedBitrateUL
UL Quality•Timer:ULQualDetRepThreshold•Data rate threshold
HHOMAxAllowedBitrateUL
DL DPCH power•Threshold:
GsmDLTxPwrThrXX•Data rate threshold
HHOMAxAllowedBitrateDL
(XX=AMR,CS,NrtPS,RtPS)
CPICH RSCP (Event 1F)•Thresholds:HHoRscpThresholdHHoRscpCancelL3 filter:HHoRscpFilterCoefficient•Timers:HHoRscpTimeHysteresisHHoRscpCancelTime
CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:Done already for SHO•Timers:HHoEcNoTimeHysteresisHHoEcNoCancelTime
AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow
GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod
Handover Triggering
Handover Execution2G-to-3G back prevention
GsmMinHoInterval
GSM measurement reporting
ISHO parameters
2 more ISHO triggers in RAN04:
• Emergency ISHO (EMISHO)
• IMSI basedISHO
104 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
ISHO measurements• After HO triggering message is sent to RNC, a RRC message ”Measurement Control” is
sent to UE containing details of the measurement that the UE must execute. Measurement reporting is periodical. Max 6 GSM cells could be measured by UE and reported to RNC. No filtering in measurements by UE
• Upon reception of the measurements reported by the UE, RNC applies a sliding averaging window to the RXLEV measurements. The averaged levels are used as input to the IS-HO decision algorithm.
RNCRRC: ”Measurement control ” message
(GSM RSSI measurements)
UE
RNC
RXLEV measurements are reported through”Measurement report” messages
UE
RRC: ”Measurement report”
RRC: ”Measurement report”
The first measurement report has info from the best GSM cell:
BCCH freq & RSSI, no filteringused in UE
GsmMeasRepInterval(default 0.5s)
105 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
ISHO Signalling
RRC: Measurement controlwith IE TGMP=”GSM RSSI”
RRC: Measurement report
. .
UE
ISHO triggered: Event 6A/1F/
RRC: Measurement controlwith IE TGMP=”GSM BSIC”
Handover from UTRAN
... .
RRC: Measurement report : BSIC decoded
RRC: Measurement report: BSIC no decoded
RNC
106 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Control Parameters: FMCG• GSMMeasRepInterval: 0.5 seconds
• This is the interval between measurement reports, which are sent to BTS• This parameter should be kept to 0.5 seconds. Increasing the reporting interval
would increase the IS-HO process delay.
• GSMMinMeasInterval:10 s• This is Minimum Measurement Interval, wait time when the following CM starts.
In case of an unsuccessful IS-HO attempt, the network will deactivate compressed mode for a time period given by this parameter, thus better value will be 2 s to speed up the reactivation of CM.
• GSMMeasAveWindow: 6• This is Measurement Averaging Window size, sliding window is used
• GSMMaxMeasPeriod: 20 reports• This is Maximum Measurement Period which determines the maximum allowed
duration of the inter-sytem measurement• If the RNC is not able to execute an inter-system Handover, it shall stop the
inter-system measurements after the UE has sent the predefined number of measurement reports to the RNC.
107 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Measurement Control Parameters: FMCG• Maximum allowed duration of the inter-system measurement is calculated:
• GSMMeasRepInterval * GSMMaxMeasPeriod (=0.5*20s) =10s,
• This seems to be too long time, because based on field measurements BSIC and RSSI delays are about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt. Proposed value for GSMMaxMeasPeriod is 6
• GSMNcellSearchPeriod: 0 • This is neighbor cell search period parameter, ISHO is not allowed until the are
enough measurement reports given by this parameter• O means that only 1 measurement result is enough for decision making• Duration of the cell search period is calculated: • GSMRepInterval * GSMNcellSearchPeriod).
108 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
ISHO: BSIC Verification• After the selection of the target GSM cell, the RNC sends to UE the RRC message
"Measurement control” which includes details to measure ”BSIC” .
• UE stops RSSI measurements and updates the transmission gap pattern to the pattern used for BSIC decoding. The measurement reports are sent periodically to RNC.
• If the UE is unable to decode the BSIC during the given period, the BSIC measurement operation is aborted.
RNC
RRC: ”Measurement control ” message (BSIC decoding)
WCDMA
IS-HO trigger Target Cell foundIS-HO
command
RSSI meas. BSIC verification
•Numbers of GSM cells in the neighbor cell list
•Reporting interval•Sliding averaging window•Transmission gap pattern forRSSI measurements
TBSIC depends on :
•Transmission gap pattern forBSIC decoding
TRSSI depends on
109 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter System Handover 3G -> 2G TuningRNC
RRC: ”Measurement report”
RRC: ”Measurement report”GsmMeasRepInterval (default 0.5s)GSMMaxMeasPeriod
Max 6 GSM cells reported RRC: ”Measurement report”
RRC: ”Measurement report”
RRC: ”Measurement Control”
Handover Command
Handover CompleteHandover Failure
•Inter-system measurement stops if RNC has not been able to perform inter-system handover after GSMMaxMeasPeriod (value 10, default =20, 1…20, step 1 meas report)•RNC could not initiate inter-system measurements if:
•The UE has « recently » performed an inter-system HO:GSMMinHoInterval / 10s, 0…60, step 1s•An inter-system HO « recently » fails for this UE: GSMMinMeasInterval /10s, 0…60, step 1s
Triggering
Details about the measurements
The first measurement report has info from the best GSM cell:
BCCH freq & RSSI, no filteringused in UE
110 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
ISHOInter System Handover 3G -> 2G Tuning
• There is a large number of parameters to optimize• However, part of the inter-system handover optimization was done empirically, based on
verification measurements done previously
2. GSM Measurement reporting process• GsmMeasRepInterval (default value=0.5 seconds)
• The GSM measurement reporting interval given by this parameter should be kept to 0.5 seconds (default value)
• Increasing the reporting interval would increase the IS-HO process delay• Besides, accuracy requirements related to the GSM measurements in compressed mode
are given for a reporting interval of 0.5 seconds (480ms TS 25.133)
• GsmMaxMeasPeriod ( default value = 20 measurement reports)• This parameter controls the maximum compressed mode duration time for each GSM
RSSI and BSIC decoding measurement process. The duration of this parameters in seconds is given by:
max_meas_time (s) = GsmMaxMeasPeriod x GsmMeasRepInterval + 4 x GsmMeasRepInterval
• Thus, the default value of max_meas_time in seconds is 12sec• it was found (based on field measurements) that BSIC and RSSI delays are below 3 seconds, it makes
senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 12 seconds has expired
• Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt
AMR
111 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
112 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
It is not sufficient to have triggers, which detect that a Handover has to be done. Criteria are required to decide, whether to carry out an intra-frequency, inter-frequency, or inter-RAT Handover – if there is the possibility for a Handover at all!
Conditions shown here have to be satisfied, before an inter-frequency Handover can be conducted. The best neighbor ing cell must fulfil following criteria („best“ according to Ec/No):
• Quality Criterion in case trigger was DL DPCH Power or CPICH Ec/No:AVE_RSCP_NCELL (n) > AdjiMinRSCP(n) + max(0, AdjiTxPwrDPCH(n) - P_MAX)
Signal level from new cell > required Signal level in new cell + adjustment due to allowed power
AVE_EcNo_NCELL (n) > AVE_CPICH_EcNo + AdjiEcNoMargin(n)EcNo on new cell better than EcNo in old cell + margin
• Pathloss Criterion in case trigger was UE Tx Power, CPICH RSCP or UL DPCH Quality:AVE_EcNo_NCELL (n) > AdjiMinEcNo(n)
EcNo on new cell better than required EcNo in new cell (default –14 dB)
CPICH_POWER - AVE_CPICH_RSCP > CPICH_POWER_NCELL (n) - AVE_RSCP_NCELL (n) + AdjiPlossMargin(n)
PathLoss in old cell > PathLoss in new cell + Margin (default 2 dB)(continued)
IFHO Decision
113 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
RRC: MEASUREMENT CONTROL (IF meas details)
UEISHO triggered: Event 6A\1F….
RNC
RRC: MEASUREMENT REPORT (Event 6A\1F..)
RRC: MEASUREMENT CONTROL (CFN, TGPS)
RRC: MEASUREMENT REPORT (CFN, TGPS)
Radio Link Setup
Periodic IF measReporting
RRC: PHYSICAL CHANNEL RECONFIGURATION (Timing Indication)
RRC: PHYSICAL CHANNEL RECONFIG COMPLETE
.
. Handover Decision
Compressed Mode Activation
RNC commandsIF measurements
and Compressed Mode
There is bad qualityconditions in the link ..
IF HO Signalling
With the informationgotten, the RNC assessthe best cell, and decides to attempt a IFHO to it
114 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter-frequency HO – Quality Criteria
HO?
a) AVE_RSCP_NCELL (n) > AdjiMinRSCP(n) + max(0, AdjiTxPwrDPCH(n) – P_MAX)b) AVE_EcNo_NCELL (n) > AVE_CPICH_EcNo + AdjiEcNoMargin(n)
AdjiMinRSCP(n)
☺
max(0, AdjiTxPwrDPCH(n) - P_MAX)
b)
AdjiMinEcNo(n)
AdjiEcNoMargin(n)☺
AVE_EcNo_NCELL (n)
a)AVE_EcNo_NCELL(n) >AVE_CPICH_EcNo + AdjiEcNoMargin(n)
115 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter-frequency HO – Pathloss Criteria
a) AVE_EcNo_NCELL(n) > AdjiMinEcNo(n)b) CPICH_POWER - AVE_CPICH_RSCP
> CPICH_POWER_NCELL(n) - AVE_RSCP_NCELL(n) + AdjiPlossMargin(n)
best active setcell
AdjiPlossMargin(n)
☺
best inter-frequencycell
b)AVE_EcNo_NCELL (n) > AdjiMinEcNo(n)
AdjiMinEcNo(n)
☺
a)
116 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
117 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
AdjgRxLevMinHO(n)
max(0, AdjgTxPwrMaxTCH(n) - P_max)
☺
AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) - P_max)
GSM cell
ISHO Decision
118 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
119 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Load based Handover GSM -> WCDMA
100%
80%
0%
Load reason Handoversfor speech
Load of GSM cell
Packet Data to WCDMAregardless of GSM load
Packet Data to WCDMAregardless of GSM load
Speech to WCDMAonly with high GSM load
Speech to WCDMAonly with high GSM load
Higher bit ratesfor data users
Higher bit ratesfor data users
More capacity for speech
More capacity for speech
Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA
Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA
120 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
GSMGSM
GSMGSM
Load and Coverage Reason Handover
GSMGSM
GSM highloaded
WCDMA lowloaded
GSMGSM GSMGSM
WCDMAWCDMA WCDMAWCDMA
Load reason Handover for speech and for HSCSD
Load reason Handover for speech and for HSCSD
WCDMAWCDMA GSMGSM
Load reason Handover
Coverage reason Handover
WCDMA can be usedto relieve GSM overload
GSM can be used to extend WCDMA coverage area
WCDMA can be usedto relieve GSM overload
GSM can be used to extend WCDMA coverage area
Mobile moving
121 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Load based Handover Process: GSM-> WCDMA
Handover Triggering Thresholds set in BSCHandover Triggering Thresholds set in BSC
Inter-RAT measurements starts in case The RXLEV of the serving cell is above or
below the given threshold Qsearch_C
Inter-RAT measurements starts in case The RXLEV of the serving cell is above or
below the given threshold Qsearch_C
Handover Decision is done in case ofLoad of the serving cell > Load_Thresholdand CPICH Ec/No> min Ec/No Threshold
Handover Decision is done in case ofLoad of the serving cell > Load_Thresholdand CPICH Ec/No> min Ec/No Threshold
MS selects the target UTRAN cell based on measurement results
MS selects the target UTRAN cell based on measurement results
Handover command is send to MSCHandover command is send to MSC
In the S10.5 MS is measuring the UTRAN cells continuously if they are defined as a neighbor ,
The number of GSM neighbor reported could be 3-6 depending on the set value of parameter FDD_MULTIRAT_REPORT (0,1,2=def,3).
The load is measured in the cell level by comparing the occupied TCHs to the available TCHs (20 s interval used)
Load Threshold for Speech Calls or Transparent Data inter-RAT Handover:utranHoThScTpdc (Min Traffic Load TDHO), default = 80%minEcnoThreshold (Min CPICH EC/NO Threshold), default –15 dB
Parameters are sent from the BSC to the mobilein the Measurement Information message
122 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
123 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Emergency ISHO (EMISHO)Directed Emergency Call Inter-system Handover directs emergency calls from UTRAN to GSM network in order to allow more accurate than Cell ID and RTT based location service.It is an optional feature and designed for US market to support FCC requirements.
Source UMTS RAN
Target GSM BSS
PSAP
GMLCGMLC
1. Emergency CallEstablishment
6. Location
2. Location Request
8. LocationRequest
9. Location
5. Positioning
3. Handover to GSM7. Location
Route of call before handover
Route of call after handover
4. Location Request
3G MSC
2G MSC
124 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
EMISHO Call-Flow
RANAP: Location Reporting Control
NBAP: Dedicated Measurement Init Req
RRC: Measurement Control UE Tx-Rx
NBAP: Dedicated Measurement Init Resp
RRC: Measurement Report Tx-Rx
Location Calculation based on CId and RTT
ISHO measurements & HO to GSM
Case a) ISHO to GSM is successful, no response to MSS
Case b) ISHO to GSM is not successful:RANAP: Location Report
Report Area IE: Geographical AreaClient Type IE: Emergency Call
SMLC
Radio Bearer setup
In case ISHO to GSM fails, RNC keeps location based on CI+RTT in mind
and sends RANAP:Location Report*
*
125 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
126 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Forced Handover for AMR Voice Call
• Feature can be used to push
3G AMR calls to 2G
• Extreme parameter setting
for ISHO trigger cause
“UE Tx power” (event 6A)
WCDMA
GSM
AMR voice call setup in 3G
forced handoverto GSM
[..]UE RNC
RRC: RadioBearerSetup
RRC: RadioBearerSetupComplete
RRC: MeasurementControl
RRC: MeasurementReport (event 6A)
FMCG: GSMcauseTxPwrUL
FMCG: GsmUETxPwrThrAMR
ISHO measurements & HO to GSM
UE immediately answers
with Measurement Report
„push“ means Handover, not Directed-Retry !
127 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Forced Handover for AMR Voice Call
• GSMcauseTxPwrUL
• Range and step: 0 (False), 1 (True)
• Indicates whether a handover to GSM caused by high UE TX power level is enabled. The handover is enabled when the value of the parameter is "Used“
• To enable feature, setting must be 1 (True)
• GsmUETxPwrThrAMR
• Range and step: -60..0 dB
• This parameter determines the UE TX power threshold for a CS voice connection. If the handover to GSM caused by high UE TX power level is enabled, the RNC starts inter-RAT (GSM) measurements when the UE TX power reaches this threshold. The UE TX power threshold is relative to the maximum TX power level an UE can use on the DPCH in the cell (or the maximum RF output power capability of the UE, whichever is lower
• To enable feature, setting must be –60 dB
128 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
129 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Reselection List
GSM MS starts WCDMA measurements if :RLA_C< F(Qsearch_I) for 0<Qsearch_I<=7
orRLA_C> F(Qsearch_I) for 7<Qsearch_I<=15
If, for suitable UMTS cell & for a period of 5 s:
CPICH RSCP > RLA_C + FDD_Qoffset
CPICH Ec/No ≥ FDD_Qmin
no prioritiesbetween WCDMA neighbor s
Measurement Updates:• RLC_C value of the serving cell• + least 6 strongest non serving GSM cells
at least every 5 s
check
and
WCDMA cellreselection
BCCH: FDD_Qmin, FDD_Qoffset
Fdd_Qoffset: selectallways (value is -infinity)
FDD_Qmin= -13 dB
Cell Reselection 2G -> 3G
130 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
• Re-selection measurements are controlled by the parameter threshold to search WCDMA RAN cells (QSRI)
• The parameter defines a threshold and also indicates whether these measurements are performed when RLA_C (a running average of received signal level) of the serving GSM cell is below or above the threshold
Cell Reselection 2G -> 3G
GSM MS starts WCDMA measurements in case running average signal (RLA_C) level is below or above
certain threshold:RLA_C # Qsearch _I (Non GPRS)
131 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Re-selection Parameters • Qsearch_I and Qsearch_P define the threshold for non-GPRS/GPRS (respectively)
capable UEs to measure 3G neighbour cells when a running average of the received downlink signal level (RLA_C) of the serving cell is below (0-7) or above (8-15) the threshold Value 0 1 … 6 7 8 9 10 … 14 15
dBm -98 -94 … -74 Always -78 -74 -70 … -54 Never
• FDD_Qoffset and FDD_GPRS_Offset the non-GPRS/GPRS (respectively) capable UEsadd this offset to the RLA_C of the GSM cells. After that the UE compares the measured RSCP values of 3G cells with signal levels of the GSM cells
Value 0 1 2 3 … 8 … 14 15
dBm -always -28 -24 -20 … 0 … 24 28
Always select irrespective of RSCP
value
Reselect in case RSCP > GSM RXLev (RLA_C) +28dB
If RLA_C>-94 UE starts 3G measurements
UE always measures 3G cells
132 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Re-selection Parameters• FDD_Qmin, defines minimum Ec/No threshold that a 3G cell must exceed, in order the UE
makes a cell reselection from 2G to 3G. This is the new mapping table
• FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default 1). This parameter is hidden and it can not be tuned
• 3G_Search_PRIO parameter allows to extend the BSIC reporting interval from 10 s to 13s by checking the BSICs from non-serving BCCH carriers and also make WCDMA measurements as often as possible. Range is 0=no, 1=yes, default value .This parameter is hidden and it can not be tuned
• Defined in the SI2quater and PSI3quater if PBCCH is allocated
ParameterParameter
Name for Sys Info (SI)Name for
Sys Info (SI)
Qsearch_IQsearch_I
2quater2quater
Qsearch_PQsearch_P Qsearch_PQsearch_P
2quater2quater 3quater3quater
FDD_QMinFDD_QMin
2ter2ter
FDD_(GPRS)Qoffset
FDD_(GPRS)Qoffset
2quater2quater
FDD_REP_QUANT
FDD_REP_QUANT
2ter2ter
3G_search_PRIO
3G_search_PRIO
2(3)quarter(PBCCH)
2(3)quarter(PBCCH)
Fdd_Qmin mappingAif parameter 0 1 2 3 4 5 6 7Fdd_Qmin (old) [dB] -20 -19 -18 -17 -16 -15 -14 -13Fdd_Qmin (new) [dB] -20 -6 -18 -8 -16 -10 -14 -12
133 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Re-selection Example-Weaker WCDMANon GPRS case
t
Serving GSM Cell
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin=0(-20 dB)
FDD_Qoffset =6 (-8 dB)
Qsearch_I=0 (-98 dBm)
RLA_C
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA Ec/N0
RSCP
134 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Re-selection Example-Weaker WCDMAGPRS case
t
Serving GSM Cell (Best)
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin=-20 dB
FDD_GPRS_Qoffset =10 (8 dB)Qsearch_P=0(-98 dBm)
RLA_P
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA
Ec/N0
RSCP
135 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Reselection 3G -> 2G
• Whilst camping in a 3G cell the UE performs intra-frequency, inter-frequency, and inter-system measurements based on the measured CPICH EcNo of the serving cell according to the following rules:
• Serving cell parameters Sintrasearch, Sintersearch and SsearchRAT are compared with Squal (CPICH Ec/No - Qqualmin) in S-criteria for cell re-selection
• UE will measure neighbor cells depending on how parameters are set & send (if parameters are not sent UE shall measure all cells)
• 1 - None (Squal > Sintrasearch ) • 2 - WCDMA intra-frequency (Sintersearch < Squal ≤ Sintrasearch)• 3 - WCDMA intra- and inter- frequency, no inter-RAT cells (SsearchRAT < Squal ≤ Sintersearch) • 4 - WCDMA intra- and inter-frequency and inter-RAT cells (Squal ≤ SsearchRAT )
Sintrasearch Sintersearch SsearchRAT
WCDMACELL
1234
136 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Reselection 3G -> 2G
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
Rn (GSM) > Rs (WCDMA)And
Rxlev (GSM) >QrxlevMin
YesNo
Cell re-selection to GSM
Neighbour WCDMA or GSM cell calculation with offset
parameter
Serving WCDMA cell calculation, with
hysteresis parameter
UE starts GSM measurements if CPICH Ec/No < qQualMin + sSearchRAT
SintraSearch
SinterSearch
SsearchRAT
CPICH EcNo
qQualMin
Second ranking only for WCDMA cells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn=CPICH_Ec/No(n)-Qoffset2 Cell re-selection to
WCDMA cell of highest R value
137 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Reselection 3G -> 2G
• UE ranks the serving cell and the measured neighboring cells to find out if reselection should be made
• All the measured suitable cells (S-criteria) are included in the ranking.
• Criteria for a suitable cell (S-criteria) is defined as • WCDMA intra-frequency neighbor cell:
– CPICH Ec/No > AdjsQqualmin and CPICH RSCP > AdjsQrexlevmin• WCDMA inter-frequency cell:
– CPICH Ec/No > AdjiQqualmin and CPICH RSCP > AdjiQrexlevmin• GSM cell:
– Rxlev > Qrxlevmin
• Ranking is done using Criteria R, and the UE reselects to the cell with highest R-criteria. R-criteria is defined as:
• For serving cell: Rs = Qmeas,s + Qhysts• For neighboring cell Rn = Qmeas,n – Qoffsetts,n
• Qmeas is CPICH Ec/No for WCDMA cell and RxLev for GSM cell
138 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Cell Reselection 3G -> 2G
• There is no timer defined how long the GSM should be fulfilling the re-selection criteria
• However there is running average of 4 GSM measurements which provides some protection against ping – pong (time vice –based on DRX cycle length and as sliding window average)
• In case additional protection is needed it can be arranged by using the Qhyst1 parameter (for WCDMA serving cell RSCP) or AdjgQoffset1(for GSM neighbor ing cell RxLev)
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
139 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
How to avoid ping pong ?• When phone is camped on 3G, GSM measurements can start when CPICH Ec/Io of
serving cell is below Ssearch_RAT + QqualMin.
• When phone is camped on GSM, cell reselection to 3G is possible if CPICH Ec/Io of the candidate is above FDD_Qmin.
• Therefore, to avoid ping pongs between 3G and GSM the following condition should be met:
FDD_Qmin >= QqualMin+Ssearch_RAT
QqualMin=-18 dB
Ssearch_RAT=4 dB
CPICH Ec/Io
FDD_Qmin >= -12 dB
QqualMin +Ssearch_RAT
tCamping on 3G Camping on GSM Camping on 3G
140 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
141 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
Inter-RNC Mobility• Most of the times the UE hands over among WBTS belonging to the same RNC (Intra-
RNC Handovers)• However, what happens when the target WBTS is under a different WBTS??• 3GPP gives two different options to handle inter-RNC mobility in WCDMA
• Anchoring: the UE will be connected to the CN via the “old” RNC. It is required Iur connection between the RNCs involved
• SRNS relocation: the UE will be connected to the CN via the “new” RNC. It is the Nokia implemented method
*) SRNS relocation needs core networksupport; UE support mandatory in 3GPP
CN
RNCRNC
Iu Iu
Iur
CN
RNCRNC
Iu Iu
Iur
AnchoringCN
RNCRNC
Iu Iu
Iur
CN
RNCRNC
Iu Iu
Iur
SRNS relocation *)
142 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
RNCRNCRNC
RNCRNC
RNC
RNCRNCRNC
RNC
SRNS Relocation
SRNS Relocation
SRNS Relocation
SRNS Relocation
SRNS Relocation
Call will drop
SRNC anchored
Anchor RNC (SRNC)
SRNS Anchoring
143 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
SRNC Relocation• The SRNC relocation is used for moving the SRNC functionality from one RNC to
another RNC, that is, closer to where the UE has moved during the communication. Both the radio access network and the core network are involved
• There are the following types of relocations• Relocation for circuit-switched services• Relocation for NRT PS services• Relocation for NRT services started by the Cell/Ura Update message from target
RNC(CELL_FACH state relocation)• Relocation for RT PS services
• An inter-RNC Hard Handover can be associated to the SRNS relocation, if so the relocation is UE involved, since the UE is ordered to switch to another carrier or to replace the whole active by sending s HHO command to the UE during the relocation procedure. An inter-RNC Hard Handover can be due to:
• Inter frequency HHO is needed, and the target cell is located in the DRNS• No resources (mainly Iur capacity) available between the involved RNCs (so no
inter-RNC SHO possible)• No Iur interface configured between the neighbour RNCs
144 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
UE not involved SRNC Relocation for RT UETarget RNC
SRNC Relocation Decision
SRNC operation started
CN
UP switching
User plane set -up
RANAP:Relocation Required
RANAP:Relocation Request
RANAP:Relocation Request Ack
RANAP:Relocation complete
RRC:UTRAN Mobility Information
RANAP:Relocation Command
RNSAP:Relocation Commit
RANAP:Relocation Detect
RRC:UTRAN Mobility Information Confirm
RANAP:Iu Release
RANAP:Iu Release Complete
User plane release
Source RNC SRNC Relocation is initiated in the Serving RNC when all the cells of the active set belong to a different RNC. The SRNC sends a Relocation Required
• The CN evaluates if the relocation is possible and in that case, it sends a Relocation Request to the target RNC with parameters for the bearer establishment
• Relocation Command sent from CN to Source RNC with UTRAN information and bearer parameters
• After that, the Source RNC sends Relocation Commit message over Iur to the Target RNC
• When target RNC starts to act as Serving RNC, it sends a Relocation Detect message to CN. This message has no parameters
• At the same time UTRAN Mobility Information is sent to the UE, to inform that the relocation is performed and should use the new RLs
• After the confirm, the target RNC informs CN with Relocation Complete –message that the relocation procedure was successful and Iu is released from source RNC
Start RelocPrep
Stop RelocPrep
Start RelocOverall
Start RelocOverall
Stop RelocOverall
Stop RelocOverall
RelocationSupport =1NrncRelocationSupport =1
145 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
UE involved: Combined SRNC Relocation and inter-RNC HHO for RT
UETarget RNC
SRNC Relocation Decision
L1 sync. Established between BTS and UE
CN
UP switching
User plane set -up
RANAP:Relocation Required
RANAP:Relocation Request
RANAP:Relocation Request Ack
RANAP:Relocation complete
Physical Ch Reconfig Complete
RANAP:Relocation Command
Physical Channel Reconfiguration
RANAP:Relocation Detect
RANAP:Iu Release
RANAP:Iu Release Complete
User plane release
Source RNC
• Because there is no Iur interface, combined SRNS relocation and HHO are done before the UE is completely under the target RNC
• The procedure is quite similar to the not UE involved case until Relocation Command
• The only difference in the Relocation Requiredmessage, the Relocation Type IE is set to "UE involved in relocation of SRNS"
• Instead of Relocation Commit via Iur, the serving RNC sends a Physical CH Reconfiguration, after which the UE stops transmitting and receiving on the old radio links and starts on the new radio link
RelocationSupport =1NrncRelocationSupport =1
Start RelocPrep
Stop RelocPrep
Start RelocOverall
Stop RelocOverall
Start RelocOverall
Stop RelocOverall
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UE reconfiguration
UE moving
RRC: TRANSPORT CHANNEL RECONFIGURATION
RRC: TRANSPORT CHANNEL RECONFIGURATION COMPLETE
Change during HO: • User Plane, Bitrate• Spreading factor• Rate matchingor:
RRC: PHYSICAL CHANNEL RECONFIGURATION
RRC: PHYSICAL CHANNEL RECONFIGURATION COMPLETEChange during HO: • Scrambling Code
RANAP: Relocation Required
UE involvedI´m involved in
relocation procedureWhole AS will change..
SRNS relocation
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SRNC Relocation Parameters• TRelocPrep : range = 1 ... 16 s, step 1 s, default = 6s
• Specifies the maximum time for Relocation Preparation procedure in the source RNC. The timer is set when a Relocation Required message is sent. The timer is stopped when a Relocation Command or a Relocation Preparation Failuremessage is received
• TRelocOverall : range = 1 ... 16 s, step 1 s, default = 8s• This timer is used in both source and target RNC. In the source RNC specifies the
maximum time for the protection of overall Relocation procedure. It is set in the source RNC when a Relocation Command message is received; and it is stopped when an Iu Release Command is received, or the relocation procedure is cancelled. The timer is set in the target RNC when a Relocation Request Acknowledgemessage is sent. The timer is stopped when a Relocation Complete message is sent, or the relocation procedure is cancelled
• T_Reloc_Inhibit_NRT : fixed to 5s• The timer is started in source RNC when a SRNC relocation procedure is triggered
for a NRT RAB(s) in a Cell_DCH state. The SRNC relocation procedure is inhibited as long as a DCH is used for the NRT RAB(s) or this timer expires
• TDataFwd : fixed to 4s• The timer is set when a SRNS Data Forward Command message (or a Relocation
Command message) is received from the PS CN. The timer is internally stopped in the SRNC when the SRNS Data Forwarding procedure has been completed
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Parameters• IuPSrelWait3G2GMultiServ : range = 0 (10s), 1 (20s), 2 (30s), 3 (60s), 4 (120s), 5
(180s), 6 (300s), 7 (600s), default value= 4 • This RNC object parameter, controls the release of the Iu-PS connection after the
3G/2G inter-system handover with CS+PS multi-service.
When the UE does not immediately after switching to the 2G-service initiate a routing area update procedure towards the PS-CN, the RNC can keep the Iu-PS connection and wait for the RAU and the release of the CS-service in the 2G-side
When the timer expires, the RNC sends the Iu release request to the SGSN• RelocationSupport : range = 0 (Not supported), 1 (Supported), default value = 1
• RNC object parameter, identifies whether the Core Network supports the relocation of SRNC or not
• NrncRelocationSupport : range = 0 (Not supported), 1 (Supported), default = 1 • RNC object parameter, identifies whether a neighbouring RNC supports relocation
of SRNC or not
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Handover Control• Handover Types• Intra-Frequency Handover:
• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release
• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:
• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision
• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection
• SRNS Relocation• IMSI Based Handover
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IMSI Based Handover – Solution Overview• IMSI based Handover is optional RAN’04 feature
• The purpose of the IMSI specific Handover feature is that a mobile subscriber in a visited network can be commanded to measure selectively only specified PLMN cells and to make Handover accordingly to those specified (home or authorised) PLMNs. The input for the selective measurement control is the PLMN id that is included in the IMSI of the subscriber.
IMSI = MCC + MNC + MSIN
MCC+MNC =PLMN IDIMSI International Mobile Subscriber IdentityMCC Mobile Country CodeMNC Mobile Network CodeMSIN Mobile Subscriber Identification NumberPLMN Public Land Mobile Network
• There are four kind of IMSI based Handover:•IMSI based Intra-frequency HO•IMSI based Inter-frequency HO•IMSI based Inter-system HO•Immediate IMSI based inter-frequency/intra-frequency HO
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IMSI Based HO• There is two new Management object class related to IMSI based HO
• WANE-WCDMA authorised networks• Authorized network identifier (AuthorisedNetworkId)• List of authorized networks (AuthorisedNetworkList)• Authorised network PLMN (AuthorisedNetworkPLMN)• Technology used in the authorised network (Technology)• WANE name (WANEName)
• WSG-WCDMA Subscriber group• Subscriber home PLMN (HomePLMN)• Name of subscriber home PLMN (OperatorName)• Subscriber Group identifier (SubscriberGroupID)• Identifier of the authorised network (WSGAuthorisedNetworkId)• GSM roaming allowed (GSM roaming)
• WANE set contains PLMN ids where the UE is allowed to make Handovers• WSG object maps the subscriber (PLMN id) to certain WANE set with a WANE id. A
WSG object should be created for every subscriber (PLMN id) visiting the network. • Max Number of WANEs is 10 and max number of WSGs is 128
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WSG – Selecting the list of Authorised PLMNs• The RNC shall select the desired list of authorised PLMNs for the selective
measurement control on the basis of the PLMN Id that is included in the IMSI of the subscriber
• The RNC links the PLMN ID of the subscriber with the desired list of authorised PLMNs by means of an index table
PLMN 242 07 Authorised PLMN list #2
IMSI 24207XXX
PLMN 24207
Each IMSI has hard coded the PLMN that
belongs to.The WSG associates
one list number (WANE ID) to each PLMN
WSG id PLMN id List id0 24305 (Op F 3G, border
country)1
1 24201 (Op B Shared 3G) 4… … …7 24207 (Op A 3G) 28 24208 (Op B 3G) 3… … …
127IMSI 24208XXX
PLMN 24208
PLMN 242 08 Authorised PLMN list #3
MCC MNC
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WANE - Structure of the Authorised PLMN lists• A list of authorised PLMNs shall contain the maximum of six PLMN identifiers
• The radio network database shall have ten separate authorised PLMN lists (WANEs)
• It is not necessary to add the home PLMN Id of the subscriber to the list of authorised PLMNs
List # Authorised PLMNs (max. 6)#1 24210 (Op D
3G)…
#2 24206 (Op A GSM
24200 (Op C 3G
24201 (Op C GSM)
24305 (Op F 3G, border country)
…
#3 24209 (Op B GSM)
24201 (Op B Sh 3G)
24210 (Op D 3G)
24306 (Op G 3G, border country)
…
#4 24208 (Op B 3G)
24209 (Op B GSM)
…
… …
#0 All …
• 'All' in the list #0 indicates that all PLMNs are considered authorised PLMNs (RNC shall combine the neighbour cell list for the inter-frequency or inter-RAT (GSM) measurement from all neighbouring cells regardless of their PLMN identifiers)
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Types of IMSI Based handover
There are five kind of IMSI based Handover:
• IMSI based Intra-frequency HO (IMSIBasedSHO=enabled)
• IMSI based Inter-frequency HO (IMSIBasedIFHO= enabled)
• IMSI based Inter-system HO (IMSIBasedGsmHO= enabled)
• Immediate IMSI based Inter-frequency HO (IMSIBasedIFHO=immediate)
• Immediate IMSI based Inter-system HO (IMSIBasedGsmHO=immediate)
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IMSI based Intra Frequency HO
• If at least one of the AS cells has IMSIbasedSHO enabled, then Intra Frequency HO is possible only if the PLMN ID of the monitored cell, which needs to be added, is the same as either the home PLMN ID of the subscriber or the authorized PLMNs or an AS cell's PLMN
• If none of the AS cells has IMSIbasedSHO enabled, then the monitored cell is added into the active set regardless of the PLMN IDs
• The IMSI based Intra Frequency HO does not affect the intra frequency measurement procedure: the RNC makes the neighbour cell lists for the intra-frequency measurements regardless of the PLMN IDs of the neighbour cells
• When a cell triggers the events 1A or 1C, the RNC checks whether fulfils the PLMN requirements, in that case it is added to the AS
• If a cell, that triggers the events 1A or 1C, does not fulfil the PLMN requirements and becomes the strongest (increases the interference), the RNC may release the RRC connection
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Example: IMSI based Intra Frequency HO
f1 f1f1
Op ACountry X
The RNC shall be able to perform inter-PLMN handovers (SHO and IFHO) within the RNC (otherwise it will not be possible to add the green operator cell to the active set)
f1 f1f1
RNC 1(Shared Op A - Op B)
Op BBorder Country
The IMSI Intra Frequency HO is between different PLMNs -> Intra Frequency Hard Handover (there is no Iur between those RNCs)
Example 1
Example 2
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IMSI based Inter Frequency/ Inter System HO
• If at least one of the AS cells has IMSIbasedIFHO/ IMSIbasedISHO enabled, then Inter Frequency / Inter System HO is possible only if the PLMN ID of the monitored cell, which needs to be added, is the same as either the home PLMN ID of the subscriber or the authorized PLMNs
• Unlike IMSI based Intra Frequency HO, the measurement list sent by the RNC in IMSI based IF/IS HO only includes the IF/IS HO cells which fulfil the PLMN requirement
• The procedure is the same for IF/IS HO causes
1. DL DPCH approaches its maximum allowed power2. Quality deterioration report from UL outer loop PC3. Low measured absolute CPICH Ec/No4. UE Tx power approaches its maximum allowed power5. Low measured absolute CPICH RSCP
158 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim
IMSI IF HO Signalling
RRC: MEASUREMENT CONTROL (IF meas details)
UEISHO triggered
RNC
RRC: MEASUREMENT REPORT (Trigger Event )
RRC: MEASUREMENT CONTROL (CFN, TGPS)
RRC: MEASUREMENT REPORT (CFN, TGPS)
Radio Link Setup
Periodic IF measReporting
RRC: PHYSICAL CHANNEL RECONFIGURATION (Timing Indication)
RRC: PHYSICAL CHANNEL RECONFIG COMPLETE
.
. Handover Decision
Compressed Mode Activation
RNC commands measurements of the authorized IF cells
There is bad quality conditions in the link ..
With the information gotten, the RNC assess the best cell, and decides to attempt a IFHO to it
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Immediate IMSI based Inter Frequency/ Inter System HO
• It is new cause that triggers the Inter Frequency or Inter System HO
• If at least one of the AS cells has IMSIbasedSHO enabled and IMSIbasedIFHO/ IMSIbasedISHO is set to immediate, then RNC starts a Immediate IMSI IF/IS HO in case the RNC cannot add a cell, which triggers the event 1A or 1C, into the AS, due to it does not fulfil the requirement of home/authorised/active set PLMNs
• It is possible to monitor a cell which does not fulfil the PLMN requirements because the RNC provides information about all the intra frequency cells, regardless of the PLMN IDs
• The compress mode is started and the RNC sends in a MEASUREMENT CONTROL message only information about the inter-frequency or inter-system cells whose PLMN is the same as either the home PLMN ID of the subscriber or the authorized PLMNs
• The IF HO/ISHO takes place normally
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Op A IMSI
Example 1 : IMSI Based IFHO ActivatedIMSI parameters in all
RNC 1 cells
IMSIbasedGsmHO=disabledIMSIbasedSHO=disabledIMSIbasedIFHO=enabled
Authorised PLMNs
#1 10011
#2 10010
#3 10020
f2
f1 f1f1
RNC 1(Shared Op A - Op B)
RNC 2(Op A)
f2
2100213810011231002011100100
List idPLMN id
WSG id
IMSI Objects in RNC 1
Op A own cell (PLMN 10010)
Op A controlled cell shared RNC(PLMN 10011)
Op B own cell (PLMN 10010)Op B controlled cell shared RNC (PLMN 10021)
Op A
Op A
Op BOp A
RNC reports all the intra-freq cells. There is no PLMN analysis since IMSIbasedSHO=disabled, so ->
Intra Freq HO to Op B cell
One of the IFSO causes reaches its threshold, so IMSI
IFHO triggered(IMSIbasedIFHO=enabled)
and RNC sends the list of the allowed cells-> IFHO to Op A
Notice that an Op B IMSI would
behave differently in
the very same scenario!!!
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Immediate IMSI HO cause conditions
1. If at least one of the AS cells has IMSIbasedSHO=enabled and IMSIbasedIFHO/ IMSIbasedISHO=immediate
2. The AS cell in question has one or more inter-frequency/inter-system neighbour cells whose PLMN ID equals either the home PLMN ID of the subscriber or a PLMN ID in the authorised list
3. The PLMN ID of a monitored cell (that has triggered the reporting event 1A or 1C) does not fulfil the requirement of the home/authorised/active set PLMNs (that is why IMSIbasedSHO=enabled is needed , otherwise it wouldn’t be possible to detect that the cell does not fulfil the PLMN requirement)
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Summarizing ….IMSI Based Intra Freq HO IMSI Based IFHO/ISHO
Immediate IMSI Based IFHO/ISHO
Settings in an active set cell
IMSIbasedSHO=enabled
IMSIbasedGsmHO= enabled/
IMSIbasedIFHO= enabled
IMSIbasedSHO= enabledAND
(IMSIbasedGsmHO=immediate /
IMSIbasedIFHO= immediate)
PLMN criteria (IMSI HO trigger)
Home\ Authorised \Active set Home\Authorised
An IMSI Intra-Freq attempt to a cell that does not fulfil the Intra Freq PLMN criteria
Neighbour list sent by the RNC
All the Intra Freq cells Only the If/IS HO cells that fulfil the PLMN criteria
Only the If/IS HO cells that fulfil the PLMN criteria
PLMN criteria applied by RNC only over a cell which is
candidate to be added in the active set
Notice the Immediate IMSI HO involves 2 cell lists: (1) To fulfil the
(IMSI Intra Freq) PLMN criteria (2)Once the Immediate IMSI is triggered, the allowed PLMN IF/IS cells where the
subscriber can hand over to
It is not required for these cells to have the IMSI feature
enabled, in order to be includedin the neighbour list. Just to
have the proper PLMN ID
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• IMSI-based Handover can be used in different network sharing cases• case 1: geographical sharing• case 2: common shared RAN with gateway core• case 3: mobile virtual network operator (MVNO)
• Based on IMSI, users of each operator can be handed over to their home or authorised WCDMA network from the shared area, when coverage becomes available (cases 1 and 2)
• Based on IMSI, inter-system Handovers to the user’s home or authorised GSM network can be performed in the shared area (all cases)
- inter-frequency HO to home or authorised WCDMA cell
- inter-system HO to home or authorised GSM network
IMSI-based Handovers from the shared area:
Different neighbor cell definitions in RNC for different IMSI ranges
IMSI Based HandoverExample Cases
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Case 1: IMSI Based Handover andGeographical Sharing
GSM GSM GSM
GSM
WCDMA
GSM GSM GSM
WCDMA WCDMA WCDMA
WCDMA WCDMA WCDMA WCDMA
GSM GSM GSM GSM GSM
Operator A GSM cellOperator A own WCDMA cellOperator A controlled sharedWCDMA cell
Operator B GSM cellOperator B own WCDMA cell
Operator B controlled shared WCDMA cell
Operator A user path Operator B user path
Based on IMSI, load and service-based inter-
system HOs to their own GSM network in shared
area
Separate neighbor lists for different IMSI ranges (different PLMN users)
Based on IMSI, operator A user is handed over to its
own WCDMA network when coverage
becomes available
GSM
GSM
Based on IMSI, operator B user is handed over to its
own WCDMA network when
coverage becomes available
Based on IMSI, users are handed over to
their own GSM networks when
WCDMA coverage ends
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Case 2: IMSI Based Handover andCommon Shared RAN
GSM GSM GSM
WCDMA
WCDMA
GSM GSM GSM
Operator A GSM cellOperator A own WCDMA cell
Common shared WCDMA cell
Operator B GSM cellOperator B own WCDMA cell
Operator A user path Operator B user path
WCDMA WCDMA
Separate neighbor lists for different IMSI ranges (different PLMN users)GSM
GSM
WCDMA
GSM
GSM
Based on IMSI, load and service-based inter-
system HOs to their own GSM network in shared
area
Based on IMSI, operator A user is handed over to its
own WCDMA network when coverage
becomes available
Based on IMSI, operator B user is handed over to its
own WCDMA network when
coverage becomes available
Based on IMSI, users are handed over to
their own GSM networks when
WCDMA coverage ends
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Case 3: IMSI Based Handover andMobile Virtual Network Operator
GSM GSM
GSM GSM
WCDMA WCDMA
Separate neighbor lists for different IMSI ranges (different PLMN users)
GSM
GSM
Operator A GSM cellOperator A controlled WCDMA cell
Operator B GSM cell
Operator A user path Operator B user path
Based on IMSI, load and service-based inter-
system HOs to their own GSM network in shared
area
Based on IMSI, users are handed over to
their own GSM networks when
WCDMA coverage ends