193219515 hsdpa-performance-improvement-discussion-nsn-20070518

1 © Nokia Siemens Networks Presentation / Author / DateFor internal use

HSDPA Performance Improvement Discussion

- April 30, 2007


HSDPA Performance Testing

• Table below is Performance table in initial and final HSDPA mobility test report and it is our target to improve and HSDPA can have better performance (enhancement). However, some might not be easy to see improvement. So we can focus on some KPI

– Application Throughput (Most important)

– HSDPA Status (channel type distribution)

– HSDPA Call Drop

– EcNo and RSCP should not be focus because not much L1 optimization and EcNo might be worse if higher average throughput (more HSDPA using)

Event Count % Uu_HSDPA_Status %Uu_PS_Attach 53 Total Time Spent in DCH_R99 73%Uu_PS_Attach_OK 53 Total Time Spent in HSDSCH 23%Attach Successful Rate 100.0% Total Time Spent in FACH 4%

Uu_PS_PDPAct_From_UE 60 Average EcNo dBUu_PS_PDPAct_From_UE_OK 60 Uu_ActiveSet_EcNo_0 -8.28PDP Activation Successful Rate 100.0% Average RSCP dBm

Uu_ActiveSet_RSCP_0 -86.19Uu_HSDPACallSetup_OK 55 Average Throughput kbpsUu_HSDPACallSetup_Fail 0 App_Throughput_DL 681.63HSDPA Call Setup Successful Rate 100.0%

Uu_HSDPA_CQI_Average 17.20HSDPA_Call Drop 4 Uu_HSDPA_NACK_Rate 8.7%HSDPA Call Completion Rate 92.7% Uu_TrCh_DownlinkBlerAgg 2.9%


HSDPA Performance Improvement (RN5.0)

• Plot right is for Channel Type Distribution in Tainan Tech Park Cluster Test on April 24

– 73% is DCH99

– 23% is HSDSCH (HSDPA)

• Application Throughput and HSDPA status can be optimized if we can increase HSDPA channel assignment or reduce Inter-frequency handover to carrier1 (No HSDPA service)

• To reduce HSDPA Call Drop, we can tune handover related parameter and make cell change smoothly


HSDPA Call Drop Case• UE sent e_1a at

11:32:25 but no cell change, it might cause not meet cell change criteria (SHO disable and Release Margin for Average Ec/No:2.5dB and Release Margin for Peak Ec/No:3.5dB)


HSDPA mobility in RAS05

•Serving Cell Change switches the user from HS-DSCH to Cell_FACH then back to HS-DSCH

HS-DSCH coverage HS-DSCH coverage

Service in HSDPA

Switching to Cell_FACH within the SHO area

UE on HS-DSCH

Cell A Cell B

HSDPA

DCH

0

Throughput

64kbps

128kbps or 384kbps according to parameter settings

Wei Yun

Cell_Fach on target cell


Details on Cell Change via cell-FACH

• HSDPA Serving Cell Change via Cell-FACH feature is used only in intra frequency handover cases, in case of IFHO or ISHO the original DCH switching procedures are used

• If the user was moved to Cell-FACH because of intra frequency handover no HSDPA user penalty timers are used on Cell-FACH, the user will be immediately switched to a new HSDPA connection when there is a data volume request either from the UE or RNC

• If the user was moved to Cell-FACH because of low throughput then the HSDPA user penalty timers are used on Cell-FACH

• If the HSDPA user moves to non-HSDPA cell, the user in HO area will be moved to Cell-FACH. The user will be immediately switched to the DCH of the requested bit rate when there is a data volume request either from the UE or RNC (no need for first DCH0/0 DCH Initial bit rate DCH Final bit rate)

• In RAS05, UE goes to cell_FACH in the current serving cell. Possible cell reselection to best server happens in cell_FACH.


EnableRRCrelease (1/4)- disabled

Measurement event 1A triggered HS-DSCH MAC-d flow release and parameter EnableRRCrelease is disabled:

UE is transferred to the CELL_FACH state and the radio bearer is mapped to

the FACH with the RRC: Radio bearer reconfiguration procedure.


EnableRRCrelease (2/4)- disabled

time

Ec/No

HSDPA AdditionTime

MR(e1A)

HSDPA AdditionWindow

P CPICH 1

HSDPA allocation FACH cell updateAddition Window (HSDPA FMCS) = 0dB

Addition Time (HSDPA FMCS) = 1280ms

EcNo Filter coefficient (HSDPA FMCS) = 800ms

SHO of the HSDPA Capable UE (RNC) = disabled

Enable RRC release (HSDPA HOPS) = disabled

Release Margin Average EcNo (HSDPA HOPS) = 2dB

Release Margin Peak EcNo (HSDPA HOPS) = 3.5 dB

EcNo Averaging Window (HSDPA HOPS) = 8

RB_Reconfiguration (FACH)

Wei Yun

addition window cannot be set to negative value


• Measurement event 1A triggered HS-DSCH MAC-d flow release and parameter EnableRRCrelease is enabled:

• For users other than HS-DSCH allocated, • EnableRRCRelease indicates whether the RRC connection release (excluding emergency calls) is allowed due to non-optimum fast closed loop power control.•For users with a HS-DSCH, • If the RNC receives measurement event 1A and the EnableRRCRelease parameter is enabled, HS-DSCH MAC-d flow release is not allowed to be triggered directly.•When a cell has entered the reporting range and triggered event 1A and the RNC has not added the cell into the active set, the UE reverts to periodical reporting. This means that the UE continues reporting after the initial report by switching to periodical measurement reporting mode.•As the EnableRRCRelease parameter is enabled, the RNC’s decision on HSDSCH MAC-d flow release is based on CPICH Ec/No of the serving cell (EcNoDownlink), CPICH Ec/No of the neighbouring cell (EcNoNcell) and the ReleaseMarginAverageEcNo and ReleaseMarginPeakEcNo control parameters.•Based on the periodic measurement reporting mode and the control parameters, the UE is transferred to the CELL_FACH state and the radio bearer is mapped to the FACH with the RRC: Radio bearer reconfiguration procedure if the following conditions are effective:•(1) EcNoDownlink + ReleaseMarginPeakEcNo(n) < EcNoNcell(n)•(2) AveEcNoDownlink + ReleaseMarginAverageEcNo(n) < AveEcNoNcell(n)

EnableRRCrelease (3/4) - enabled

Wei Yun

if either one condition met, cell change will be triggered


EnableRRCrelease (4/4) - enabled

time

Ec/No

HSDPA AdditionTime

Periodic MR(e1A)

HSDPA AdditionWindow

P CPICH 1

HSDPA allocation FACH cell updateAddition Window (HSDPA FMCS) = 0dB




Enable RRC release (HSDPA HOPS) = enabled




ReleaseMarginAverageEcNoReleaseMarginPeakEcNo

RB_Reconfiguration (FACH)

Wei Yun

enable this parameter is to delay the cell change process


HSDPA Call Drop Case (1) • UE sent e_1a at

11:32:25 but no cell change, it might cause not meet cell change criteria (SHO disable and Release Margin for Average Ec/No:2.5dB and Release Margin for Peak Ec/No:3.5dB)

Log file for RAS5.0 test


HSDPA Call Drop Case (2) • UE sent e_1a again at

11:32:36 but might be too late (addition window: 0dB and addition time: 320ms) to perform cell change, drop due to bad EcNo

• Handover related parameter can be tuned to avoid this kind of drop

• Signaling SHO can be performed in RAS5.1 and UE no need to enter cell-FACH for serving cell change. Can adjust addition window and time to perform SHO earlier

Drop


• In HSDPA service, UE will perform cell change after RRC release criteria fulfill

• Parameters: Release Margin for Average Ec/No:2.5dB and Release Margin for Peak Ec/No:3.5dB

• RNC refer to EcNo of active set and monitor set in e_1a MR

• E_1a parameter in FMCS for HSDPA is used

– Addition window:0dB

– Addition time: 1280ms

– Filter coefficient: 600ms

• In case, 1st e_1a MR sent by UE but EcNo of active set is -23dB, cell change might not be performed properly (UE can’t decode RB reconfiguration)

• SHO can be performed in RAS5.1

HSDPA Call Drop Case - adjust event_1a addition time and fc


HSDPA Call Drop Case - adjust event_1a addition time and fc

• Another case have the similar problem

• Many call drop have similar situation

• Delay cell change in HSDPA service must be considered because throughput gap in cell-FACH during cell change. But it can be controlled by parameters:

– Release Margin for Average Ec/No:2.5dB

– Release Margin for Peak Ec/No:3.5dB

• E_1a parameter in FMCS for HSDPA can be adjusted to trigger earlier to avoid drop

– Addition window:0dB

– Addition time: 320ms

– Filter coefficient: 300ms


Serving Cell Change Functionality Verification (SHO for HSDPA user) _ Message Flow (RN5.1)

After SW upgrade: Test on April 29

ASU to add SC 267

Measurement control to ask UE to perform Periodical EcNo reporting

Periodic EcNo report

RAB reconfiguration for Serving cell change to SC267

No RAB reconfiguration to ask UE to cell-FACH for Serving cell change

ASU to remove SC208

No Physical channel reconfiguration in intra-NodeB handover (Softer handover)


HSDSCH to DCH

• UE sent e_1f of SC169 11:34:25 (active set is 1 in HSDPA in RAN5.0)

• Before compress mode (physical channel reconfiguration), RNC have sent two radio bearer reconfiguration. One is for 0/0 bit rate and another is for initial bit rate (64/64)


IF/IS Handover Measurement 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/1F FMCI: IFHOcauseCPICHEcNoFMCG: GSMcauseCPICHEcNo

Measurement

Trigger

6 . Others- Load and Service based HO- IMSI based HO- Emergency ISHO

Frequency Measuring Control for Inter-Frequency = FMCIFrequency Measuring Control for Inter-System (GSM) = FMCG


1. Measurement trigger CPICH Ec/No

Reporting event: 1E: A P-CPICH exceeds an absolute threshold 1F: A P-CPICH falls below an absolute threshold (HO

triggered if all)

time

Cell 1 Cell 2

Cell 3

absolutethreshold

e.g

. P

-CP

ICH

Ec/N

o

1E: HHoRSCPCancel

1E: HHoEcNoCancelTime

1F: HHoRSCPThreshold

1F: HHoEcNoTimeHysteresis


HSDSCH to DCH but no Physical Channel Reconfiguration (CM mode didn’t be triggered) (1)




HSDSCH to DCH but no Physical Channel Reconfiguration (CM mode didn’t be triggered) (2)

• However, UE sent e_1e of SC169 11:34:27 (active set is 1 in HSDPA in RAN5.0), so compress mode didn’t start (no physical channel reconfiguration) and UE stay in Carrier2 (no IFHO)

• But UE is in DCH99, not in HSDSCH channel, radio bearer reconfiguration is update UE to R99 Max bit rate in downlink, UL/DL: 64/384)

• NRT SHO criteria will be used to perform SHO and might cause HSDPA didn’t be used again (resumption didn’t expire)

• No IFHO but DCH99 is used due to signal fading, better to adjust e_1f criteria to avoid it.


HsdschGuardTimerHO

HS-DSCH guard time after switching to DCH due to HO

The parameter determines a period of time during which the HS-DSCH allocation is denied after successful channel type switching from HS-DSCH to DCH 0/0 kbps due to handover reasons(e1F, e6A).

Timer is not applied if UE is transferred directly to the CELL_FACH state due to reporting event 1A.

Range and step 0...30 s, step 1 s

Default value 5 s


Inter-Frequency Handover (1)



• Different with previous case, no e_1e from UE, so compress mode is triggered (first physical channel reconfiguration)

• Measurement report to report ADJI measure. If fulfill HO criteria, RNC send second physical channel reconfiguration to ask UE to carrier1


Inter-Frequency Handover (2)

• UE is in carrier1 and DCH99 is used because HSDPA didn’t implement in carrier1. NO chance to use HSDPA service because no ADJI setting in cell of carrier1.

• HSDPA can be used in next call by DRRC function

• To evaluate if this IFHO is necessary. If didn’t perform, will cause PS drop? try to adjust e_1f criteria to avoid IFHO and no drop.


No HSDSCH assignment ( >1 active set before RAB reconfiguration)

• More than 1 active set before RAB reconfiguration though SHO not allow for HSDPARRCDiversity parameter (follow RRC Release criteria for HO). RNC won’t assign HSDSCH, instead of DCH99

• Parameters: Release Margin for Average Ec/No:2.5dB and Release Margin for Peak Ec/No:3.5dB can be considered to adjust, but drop must be avoided.

• Cell reselection related parameter can adjust to avoid UE camp to worse cell to initial call

• HSDPA can be assigned even Active set more than 1 in RAS5.1 and Serving cell change function but worse cell to initial call still need to avoid


CHANNEL TYPE SELECTIONHS-DSCH is selected if all of the following conditions are met:1. Traffic class and traffic handling priority are allowed on HS-DSCH

1. The operator can configure which traffic classes and handling priority are allowed to be used with HSDPA with HSDSCHQoSclasses parameter.

2. RAN05 only interactive and background traffic classes are supported

2. UE capability supports HS-DSCH

3. The cell supports HSDPA and HS-DSCH is enabled in the cell

4. No multi-RAB (RAN05) or supported multi-RAB combination (RAN05.1)

1. No multiRAB in RAN05

2. AMR + HSDPA possible in RAN05.1

5. The number of simultaneous HS-DSCH allocations in the BTS/cell is below the maximum number.

6. HsdschGuardTimerHO and HsdschGuardTimerLowThroughput guard timers are not runnig

1. Both guard timers are operator-configurable parameters

7. UE is not performing inter-frequency or inter-system measurements

8. Active set size = 1 (RAN05)

9. UE does not have DCHs scheduled with bit rates higher than 0kbps.

10. HS-DSCH physical layer category is supported

11. If there is no existing MAC-d flow in the cell, condition (A or B, depending on the HSDPApriority parameter) has to be valid.

1. A) PtxNC<=PtxtargetHSDPA

2. B) Ptxtotal<=PtxtargetHSDPA


HSDPARRCdiversity (1/4)- Diversity handover of stand-alone signalling link

•If the active set size is greater than one, allocation of a HS-DSCH transport channel to the UE is prohibited.

•The operator can disable diversity handover of the RRC connection (stand-alone signalling link) of a HSDPA-capable UE with the HSDPARRCdiversity parameter to maximise the use of the HS-DSCH.

•The value of the parameter HSDPARRCdiversity shall be checked immediately after a successful RRC connection setup procedure.

•If SHO of the RRC connection (stand-alone signalling link) of the HSDPA-capable UE is not allowed, the active set size is limited to one for the RRC connection.

•Restriction is effective after RRC-connection establishment when SRB only or SRB and DCH 0/0 is/are allocated.


• The RNC ignores the parameter value (and allows diversity handover of standalone signalling link) if measurement event 1A is received and the reported CPICH Ec/No of the entering cell meets the following conditions (that is, the threshold to perform HS-DSCH to Cell_FACH transition is exceeded):

(1) EcNoDownlink + ReleaseMarginPeakEcNo(n) < EcNoNcell(n)

(2) AveEcNoDownlink + ReleaseMarginAverageEcNo(n) < AveEcNoNcell(n)

EcNoDownlink :CPICH Ec/No of the serving cellEcNoNcell(n) : CPICH Ec/No of the entering cell AveEcNoDownlink : averaged CPICH Ec/No of the serving cellAveEcNoNcell(n) : averaged CPICH Ec/No of the entering cell

• The comparison is applied when a cell has entered the reporting range, and triggered event 1A, and RNC has not added the cell into the active set.

• In this case, the UE reverts to periodical reporting and continues reporting after the initial report by switching to the periodical measurement reporting mode.

• ReleaseMarginPeakEcNo(n) determines the maximum allowed difference between the CPICH Ec/No of the entering cell (n) and the CPICH Ec/No of the serving cell so that active set update is not executed.

• ReleaseMarginAverageEcNo(n) determines the maximum allowed difference between the averaged CPICH Ec/No of the entering cell(n) and the averaged CPICH Ec/No of the serving cell correspondingly.

• The HSDPA-specific HOPS parameters are used in the equation.

HSDPARRCdiversity (2/4)- Diversity handover of stand-alone signalling link - Exception


HSDPARRCdiversity (3/4) - Diversity handover of stand-alone signaling link

Ec/No

P CPICH 2

DCH AdditionWindow

P CPICH 1

Call StartHSDPARRCDiversity: Not AllowedAddition Window (HSDPA FMCS) = 0dB




Enable RRC release (HSDPA HOPS) = enabled





Periodic MR (e1A)

DCH Addition Time

ASU

DCH DeletionWindow

DCH Deletion Time

MR (e1B)

ASU

2 Active Set

HSDPA

Allocation

Stand-alone Signalling Link


HSDPARRCdiversity (4/4) - Diversity handover of stand-alone signaling link

Ec/No

P CPICH 2

DCH AdditionWindow

P CPICH 1

Call StartHSDPARRCDiversity: Not Allowed


Periodic MR (e1A)

DCH Addition Time

ASU

DCH DeletionWindow

DCH Deletion Time

MR (e1B)

ASU

Stand-alone Signalling Link

DCH Allocation

HSDPA Resumption Timer

HSDPA Allocation

* HSDPA enabled for both Serving & Target Cells


• More than 1 active set before RAB reconfiguration though SHO not allow for HSDPARRCDiversity parameter (follow RRC Release criteria for HO). RNC won’t assign HSDSCH, instead of DCH99

• Parameters: Release Margin for Average Ec/No:2.5dB and Release Margin for Peak Ec/No:3.5dB can be considered to adjust, but drop must be avoided.

• Cell reselection related parameter can adjust to avoid UE camp to worse cell to initial call

• Drop window and time can be adjusted

• HSDPA can be assigned even Active set more than 1 in RAS5.1 and Serving cell change function but worse cell to initial call still need to avoid

No HSDSCH assignment - adjust event_1b drop time and window


No HSDSCH assignment - adjust event_1b drop time and window

•Objective: try to keep 1 active set as possible before HS-DSCH assignment (RAB reconfiguration.•No E_1b MR might cause drop-window (6dB) and time setting (640ms) though 5 dB difference between 2 active set. If change drop window smaller and drop time short (FMCS for HSDPA). Event_1b might be triggered and HS-DSCH might be assignment (active set is1)

•E_1b parameter in FMCS for HSDPA is used in SRB period. It is not affect after RB assignment (RT/NRTFMCS will be used in RT/NRT DCH, Cell-change will be used in HSDPA)

•Ping-pong addition and deletion? “NO”

• SHO not allow for HSDPARRCDiversity

• Addition window is 0dB


HSDSCH assignment ( >1 active set before RAB reconfiguration)- For reference and not for tuning)- RN5.1

• HSDSCH can be assigned even more than 1 active set before RAB reconfiguration


Test in RN42

Scenario1:

Change parameter in FMCS61

HHoRscpThreshold: -105dB (from -95) HHoRscpCancel:-102dB (from -92)

Initial Test


Test in RN42

Scenario1:


HHoRscpThreshold: -105dB (from -95) HHoRscpCancel:-102dB (from -92)

Scenario1+ Scenario2


HHoRscpThreshold: -105dB (from -95)

HHoRscpCancel:-102dB (from -92)


Addition Time: 320ms (from 1280ms)

Filter Coefficient:300ms (from 600ms)

DropWindow: 2dB (from 6dB)

Drop timer: 320 ms (from 640ms)

How to reduce drop?


RAS5.1


Inter-Frequency Handover

• In RAS 05, unnecessary CM preparation (HSDSCH to DCH) must be reduction (same as RAN5.0), no matter compress mode have been triggered or not

• Except e_1f parameter can be adjusted, SHO related can be adjusted to avoid HSDSCH to DCH99

• Measurement report to report ADJI measure. If fulfill HO criteria, RNC send second physical channel reconfiguration to ask UE to carrier1

• Case left, UE sent e_1f earlier than e_1a (SC142:89). If add SC142 earlier, CM preparation (HSDSCH to DCH) or IFHO might not be performed

Log file


NO dominator server

• This area have mess signals and strength is very close (SC 161, 169, 142, 211 and 280)

• L1 optimization can be considered if not affect carrier1 performance (Actual, L1 tuning might help to improve carrier1 performance, too)


No HSDSCH after serving cell change? (RAS5.1)

• Original Active set is SC203 and SHO to add SC280

• SC280 is stronger in periodic measurement EcNo report

• RNC have sent two radio bearer reconfiguration. One is for 0/0 bit rate and another is for initial bit rate (64/64)-DCHR99 but no HSDSCH. Fail serving cell change?

• Possible to cause by ULSIRError problem

• Under investigation

Log file


HSDPA Testing in Tainan Tech Park

• HSDPA performance comparison between “before” and “after SW upgrade” might not be fair and corrected because the test area haven’t tuned and percentage of HSDPA using is low. Suggest to test in fine tuned area for comparison

After SCC SW upgrade: Test on April 28

Before SCC SW upgrade: Test on April 16

Event Count % Uu_HSDPA_Status %Uu_PS_Attach 16 Total Time Spent in DCH_R99 67.74%Uu_PS_Attach_OK 16 Total Time Spent in HSDSCH 32.15%Attach Successful Rate 100.0% Total Time Spent in FACH 0.11%




Event Count % Uu_HSDPA_Status %Uu_PS_Attach 16 Total Time Spent in DCH_R99 58.0%Uu_PS_Attach_OK 16 Total Time Spent in HSDSCH 42.0%Attach Successful Rate 100.0% Total Time Spent in FACH 0.0%





Test Result _ Parameter Change

Test day: May 4

Parameter change:

• HSDPAresumptiontimer:2s

• MACdflowutilTimetoTrigger: 5s

• HsdschguardtimerLowThroughput: 0s

• Didn’t change back

• Can’t say throughput is worse because most of time use cell-DCH



Test day: May 8

Parameter change: (Scenario 1)

– HSDPASIRErrorServCell: -7dB

– HSDPASIRErrorTargetCell:-6dB

– Didn’t change back

• Can’t say throughput is worse because most of time use cell-DCH

Scenario2: Change parameter in RNC

HSDPASIRErrorReportPeriod:0

Didn’t complete test due to problem observe


Problem in Scenario2 Test:

HS_DSCH assignment and throughput can be observed in test, should not have problem if set HSDPASIRErrorReportPeriod:0


Problem in Scenario2 Test: After data transfer and PDP deactivation, no detach from UE and no RRC release for long time. can’t sure if it is tool problem, better to re-test. If problem still, can add attach /detach in script



Test day: May 8

Parameter change: (Scenario 3)

– HHoRscpThreshold: -105dB

– HHoRscpCancel:-102dB

– change back

• Throughput is much better but drop increase, should analyze and improve drop rate (Handover related parameter?)


HSDPA Cluster Follow up:

1. L1 optimization

2. SHO parameter tuning, ex: addition window and time

3. HHoRSCP threshold/cancel parameter tuning

• Border cell/ inner cell

• PS drop and must be analysed

• KPI need to monitor

• “HSDPASIRErrorReportPeriod:0” test


Appendix

Initial HSDPA Serving Cell Selection

HSDPA Serving Cell Change

• Introduction

• Periodical CPICH Ec/No Measurements

• CPIHC Ec/No Triggered SCC

• Periodical UL SIRerror Triggered SCC

• Periodical UL SIRerror Measurements

• Event 1B Triggered SCC

• Event 1C Triggered SCC

• RL Failure, Serving HS-DSCH Link Moved to DRNC, RL Removal Due to 6F, 6G

• Too Frequent Serving Cell Changes

• ISHO with SCC


Contents

HS-DSCH AC

Dynamic Power Allocation (DPA)

Link Adaptation Optimisation

Proportional Fair Scheduler


HSDPA Serving Cell Change• Introduction









• ISHO with SCC


HSDPA Initial Serving Cell Selection

Note that in order to allocate HS-DSCH, HS-DSCH channel type selection algorithm must be successful, i.e. UE and Cell/BTS must fulfill all the criteria regarding HS-DSCH allocation

The serving HS-DSCH cell selection algorithm is executed when a NRT PS RAB is established and a capacity request leads to the HS-DSCH allocation

• UL return channel allocation must also be successful in order to allocate HS-DSCH transport channel

Initial serving HS-DSCH cell selection is based on the latest received intra-frequency DL CPICH Ec/No measurement result reported by UE

If the size of the active set is one, i.e. there is only one cell in the active set, DL CPICH Ec/No is not used as criteria, but HS-DSCH allocation can be executed without taking it into account


If the size of the active set is greater than one, i.e. there is more than one cell in the active set, DL CPICH Ec/No is used as criteria

All the HSDPA-capable cells, which fulfil the following condition, are selected as possible candidate cells for HS-DSCH allocation:

Where CPICHEc/NoCell is the CPICH Ec/No measurement of the candidate cell, CPICHEc/NoCell is the CPICH Ec/No measurement of the best cell in the active set and HSDPAServCellWindow (def. 2dB) is the management parameter, which determines the window – relative to the best cell in the active set – inside of which the serving HS-DSCH cell must be in order to allocate HS-DSCH

)_( // ellWindowHSDPAServCcellBestCPICHCellCPICH NoEcNoEc


Wei Yun

condition to find candidate list


When the cells, which fulfil the DL CPICH Ec/No condition are found, the serving HS-DSCH selection is executed according to the following priorities:

1. The cell, which has already HSDPA power allocated is chosen as the serving HS-DSCH cell– If several cells fulfil the criterion, DL CPICH Ec/No determines the order of the cells

2. The cell, which has the best DL CPICH Ec/No is chosen as the serving HS-DSCH cell

3. The cell, which has the next best DL CPICH Ec/No (first 2nd and then 3rd best) is chosen as the serving HS-DSCH cell

If the RL is out of synchronisation, it is excluded from the candidate list for the serving HS-DSCH cell

If allocation of the HS-DSCH fails or is unsuccessful due to any reason, the next best cell, in accordance with the priorities above, is attempted

• If none of the cells in the active set can be chosen as the serving HS-DSCH cell, or if all the attempted allocations of the HS-DSCH are unsuccessful, DCH is scheduled immediately, i.e. capacity request is handled without queuing



HSDPA Initial Serving Cell Selection – Resumption TimerDCH to HS-DSCH switch is attempted if conditions for HSDPA connections are fulfilled for certain time period• This time period is defined by non hidden RNP parameter HSDPAResumptionTimer (def. not in use)The Handover Control starts HSDPA resumption timer when the following preconditions are fulfilled:• PS I/B RB has been mapped to DCH > 0/0• UE is HSDPA capable• cell is HSDPA capable• Active set size is 1 RAN05 or in RAN05.1 when HSDPAMobility parameter is disabled• Active set contains at least one HSDPA capable cell in RAN05.1 when HSDPAMobility is activated• UE has suitable RAB configuration

(allowed RAB configurations can be found from requirement HSDPA.6) • Resumption timer functionality is activated (the value of the timer does not indicate it is off)• HSDPA resumption prevention timer is not activeThe Handover Control stops the HSDPA resumption timer for the following reasons:• In RAN05 or in RAN05.1 when HSDPAMobility parameter is disabled

- Handover (active set change, compressed mode is initiated)• In RAN05.1 when HSDPAMobility parameter is enabled

- there is no HSDPA capable cell in the active set anymore- compressed mode is initiated

• RAB configuration changes so that HSDPA is not possible anymore(allowed RAB configurations can be found from requirement HSDPA.6)

• NRT DCH is released


HSDPA Initial Serving Cell Selection – Resumption TimerIn RAN05.1, when the HSDPAMobility parameter is enabled, the periodic CPICH Ec/No measurement is used to check the quality of HSDPA capable cell (check the Periodical CPICH Ec/No Measurements section)When the active set size is 1, then the Handover Control asks DCH to HS-DSCH switch from the UE specific PS if HSDPA resumption timer expiresWhen the active set size is bigger than 1, then the handover control checks condition for initial HSDPA service cell selection, after the resumption timer expires

• This means that the switch can not be started until at least one CPICH Ec/No measurement report is received (for example in the case where the value of the resumption timer is 0 s)

• If the condition is fulfilled (good enough HSDPA capable cells are found) then the handover control asks DCH to HS-DSCH switch from the UE specific PS



HSDPA Initial Serving Cell Selection – Resumption Timer

Switch (DCH -> HS-DSCH) can be refused for the following reasons:

• There exists parallel procedures for the UE (UE specific PS)

• It is not possible to allocate HSDPA power to the cell (cell specific PS)

• Nbr of HSDPA users is exceeded for the cell/BTS (cell specific PS)

• HdschGuardTimerHO (def 5s) or HsdschGuardTimerLowThroughput (def 30s) is running

If the switch can not be done or is refused, then the Handover Control starts HSDPA resumption prevention timer (5s, 10s, 15s)

• Resumption timer can be started again after HSDPA resumption prevention timer has expired

• HSDPA resumption prevention timer is increased by 5 seconds every time it is started (i.e. every time the switch DCH -> HS-DSCH is consecutively refused)

• However maximum value for HSDPA resumption prevention timer is 15 seconds


HSDPA Initial Serving Cell Selection – Resumption Timer

When DCH to HS-DSCH switch is being made then the following things are done:

• DCH is released

• RB is mapped to DCH 0/0

• normal channel type selection is made to get a HS-DSCH channel, when the next capacity request is received

The HS-DSCH allocation follows the principles specified for the MAC-d flow setup starting in the Cell-DCH state

• A HS-DSCH is added, MAC-d flow setup and UL/DL DCH replaced with the unidirectional UL DCH with the same synchronised RRC- and NBAP-procedures


Contents

HS-DSCH AC














• ISHO with SCC



RAS05 solution via FACH• Cell change via FACH causing typically 3 s break• HSDPA not available in soft handover soft handover is disabled for HSDPA connections

RAS05.1 solution with HSDPA serving cell change• Direct handover from Cell A HSDPA to Cell B HSDPA. Connection break in good case

<100 ms.• Uplink soft handover can be used also for HSDPA connections

Cell with HSDPA capabilityCell without HSDPA capability

12

3

Wei Yun

In RAS5.1, SHO is capable in SRB and UL



The serving HS-DSCH cell change is based on the intra-frequency CPICH Ec/No measurements reported periodically by the UE and dedicated UL SIRerror measurements reported periodically by the BTS

The serving HS-DSCH cell change may be categorized in regards to whether the decision of the target HS-DSCH cell is made by the UE or by the network

• In Release 5 (RAN05.1), only network controlled serving HS-DSCH cell changes are supported

In the case of a network-controlled serving HS-DSCH cell change the network makes the decision of the target HS-DSCH cell, and the decision is based on UE and BTS measurement reports, different management parameters and available RNC and BTS resources

• A network controlled HS-DSCH cell change is performed as RRC layer signaling procedures to UE



With respect to synchronisation between UE and UTRAN as to when transmission and reception is stopped and re-started, two possibilities for a serving HS-DSCH cell change exist:

• Synchronised serving HS-DSCH cell change: Start and stop of HS-DSCH transmission and reception is performed at a certain time typically selected by the network; (RAN05.1)

• Unsynchronised serving HS-DSCH cell change: Start and stop of HS-DSCH transmission and reception is performed "as soon as possible" (stated by UE performance requirements) at either side (not supported in RAN05.1)



The serving HS-DSCH cell change may be categorized with respect to the serving HS-DSCH Node B:

• Intra-Node B serving HS-DSCH cell change: The source and target HS-DSCH cells are both controlled by the same Node B

– The serving HS-DSCH Node B is not change

• Inter-Node B serving HS-DSCH cell change: The Node B controlling the target HS-DSCH cell is different from the Node B controlling the source HS-DSCH cell

UE

Original Serving

Cell Node B

1HSDPA Traffic

NBAP: Radio Link Setup Response

Measurement Report (DCH) – e1A

RRC: Active Set Update (DCH)

NBAP: Radio Link Setup

NBAP: Radio Link SynchronisationRRC: Active Set Update Complete (DCH)

NBAP: Radio Link Reconfiguration Prepare

NBAP: Radio Link Reconfiguration Ready

RRC: Measurement Control

NBAP: Radio Link Reconfiguration Commit

RRC: Physical Channel Reconfiguration


RRC: Physical Channel Reconfiguration Complete (DCH)

Measurement Report (DCH)



NBAP: Radio Link Reconfiguration ReadyNBAP: Radio Link Reconfiguration Ready

ALCAP : ERQ


ALCAP : ECF

NBAP: Radio Link Reconfiguration CommitNBAP: Radio Link Reconfiguration Commit

RRC: Radio Bearer Reconfiguration

RRC: Radio Bearer Reconfiguration Complete (DCH)

Target Serving

Cell Node B

2



Serving HS-DSCH cell change algorithm is executed when HS-DSCH is allocated and need for the serving HS-DSCH cell change is detected

The measurements and reasons, which may trigger serving HS-DSCH cell change are the following ones:

• Periodical CPICH Ec/No measurement

• Periodical UL SIRerror measurement

• Measurement event 1B– Serving HS-DSCH cell is removed from the active set

• Measurement event 1C– Serving HS-DSCH cell is replaced with another cell

• RL failure of the serving HS-DSCH radio link (loss of UL synchronisation)– Serving HS-DSCH radio link is deleted

• Serving HS-DSCH radio link is handed over to DRNC

• RL removal due to Rx-Tx time difference– Serving HS-DSCH radio link is deleted

Each case is specified in detail in separate requirements



Following event triggered measurements are order by RNC to be performed by the UE having HS-DSCH allocation

• Event 1A

• Event 1B

• Event 1C

• Event 1E

• Event 1F

• Event 6F

• Event 6G

And periodical measurements

• Periodical CPICH Ec/No measurements (in case AS size > 1)

The serving HS-DSCH cell change is based on the intra-frequency CPICH Ec/No measurements reported periodically by the UE and dedicated UL SIRerror measurements reported periodically by the BTS


Contents

HS-DSCH AC














• ISHO with SCC


Periodical CPICH Ec/No Measurements

Intra-frequency measurement reporting criteria of the periodical CPICH Ec/No measurement is determined in the following way:

• Measurement reporting mode is fixed– Transfer Mode is 'Acknowledged mode RLC'

– Reporting Mode is 'Periodical reporting'

• Measurement quantity is CPICH Ec/No– Filtering of CPICH Ec/No measurement in UE is controlled with the RNP-

parameter EcNoFilterCoefficient, defined by the HSDPAFmcsIdentifier or RTWithHSDPAFmcsIdentifier parameter set

• Reporting quantity is CPICH Ec/No for active set cells – fixed

• Reporting criteria is periodical reporting– The reporting interval is determined by the RNP-parameter

HSDPACPICHreportPeriod

Wei Yun

will be triggered by network when there is > 1 active set



Periodically reported DL CPICH Ec/No measurement results are averaged in RNC

HSDPACPICHAveWindow (def 3) is RNC specific parameter, which defines how many CPICH Ec/No measurements, which are received in the RRC: MEASUREMENT REPORT message, are included in the sliding window used in the averaging

CPICH Ec/No is averaged using the following formula:

• Where CPICHEc/No (t) is the latest CPICHEc/No measurement and n equal to HSDPACPICHAveWindow

• RNC starts the averaging already from the first measurement sample, that is, the RNC calculates the averaged values from those measurement samples which are available until the number of measurement samples is adequate to calculate averaged values over the whole averaging window (=> serving HS-DSCH cell change can be initiated based on 1st Measurement Report as longs as conditions are fulfilled)

• RNC calculates the averaged values directly from the measured dB values, linear averaging is not used in this case

n

ntCPICHtCPICHtCPICHCPICH NoEcNoEcNoEc

NoEc))1((...)1()( ///

/



Whenever the AS>1 for HSDPA call the RNC orders the UE to start to perform periodical CPICH Ec/No measurements

UE RNCNode B 1

HSDPA Traffic



Node B 2










Setting up periodical Ec/No measurements for HS-DSCH serving cell change procedure

Periodical CPICH Ec/No measurement are started only if the size of the active set is greater than one. If the size of the active set is one, periodical CPICH Ec/No reporting is not started and if on going stopped

DL-DCCH-Message {

integrityCheckInfo {

messageAuthenticationCode '0111010101010011111110011001

0010'B,

rrc-MessageSequenceNumber 12

}, message measurementControl : later-than-r3 : {

rrc-TransactionIdentifier 3,

criticalExtensions r4 : {

measurementControl-r4 {

measurementIdentity 5,

measurementCommand setup : intraFrequencyMeasurement : {

intraFreqMeasQuantity {

filterCoefficient fc3,

modeSpecificInfo fdd : {

intraFreqMeasQuantity-FDD cpich-Ec-N0 } },

intraFreqReportingQuantity {

activeSetReportingQuantities {

dummy noReport,

cellIdentity-reportingIndicator FALSE,

cellSynchronisationInfoReportingIndicator FALSE,


cpich-Ec-N0-reportingIndicator TRUE,

cpich-RSCP-reportingIndicator FALSE,

pathloss-reportingIndicator FALSE } },

monitoredSetReportingQuantities {

dummy noReport,




cpich-Ec-N0-reportingIndicator FALSE,


pathloss-reportingIndicator FALSE } } },

reportCriteria periodicalReportingCriteria : {

periodicalReportingCriteria {

reportingInterval ril0-5

}, reportingCellStatus withinActiveSet : e3 } },

measurementReportingMode {

measurementReportTransferMode acknowledgedModeRLC,

periodicalOrEventTrigger periodical } },

v4d0NonCriticalExtensions {

measurementControl-v590ext {

rrc-TransactionIdentifier-MSP-v590ext 1

} } } } } }


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change - Periodical CPICH Ec/No Measurement TriggeredWhen the serving HS-DSCH cell change due to any reason has successfully been executed, the timer is started

During the time period, determined by the parameter HSDPACellChangeMinInterval (def 3s), serving HS-DSCH cell change due to periodical CPICH Ec/No measurement, is not allowed for the particular UE

The serving HS-DSCH cell change due to any other reason is NOT forbidden even if the timer is running

Wei Yun

HSDPACellChangeMinInterval only valid for periodical CPICH measurement. If cell change triggered by other reason, this timer is ignored.


HSDPA Serving Cell Change - Periodical CPICH Ec/No Measurement Triggered

When UE reports periodical intra-frequency CPICH Ec/No measurement report, need for the serving HS-DSCH cell change is evaluated (UE is ordered to report periodically the CPICH Ec/No values of the AS cells when AS size > 1)If the CPICH Ec/No of the serving HS-DSCH cell is not close enough to the currently best cell in the active set, serving HS-DSCH cell change is initiatedThe condition to initiate serving HS-DSCH cell change is defined in the inequality below

If CPICH Ec/No of the serving HS-DSCH cell is greater than or equal to the threshold, determined by the parameter HSDPACPICHEcNoThreshold (def -5dB), serving HS-DSCH cell change is not initiated but the current serving cell is keptIf the CPICH Ec/No of the serving HS-DSCH cell is greater than or equal to CPICH Ec/No of the best cell subtracted with the value of the parameter HSDPAServCellWindow (def 2dB), serving HS-DSCH cell change is not initiated • CPICHEc/NoServ_cell is the average CPICH Ec/No measurement result of the serving HS-DSCH

cell• CPICHEc/NoBest_cell is the average CPICH Ec/No measurement result of the best cell in the active

set • HSDPAServCellWindow is the management parameter , which determines the window - relative to

the best cell in the active set - inside of which the serving HS-DSCH cell must be in order to allocate HS-DSCH

)_(_ // ellWindowHSDPAServCcellBestCPICHcellServCPICH NoEcNoEc


HSDPA Serving Cell Change – Impact of Other & Own Cell InterferenceLooking into the target HSDPA service cell selection formula

• The parameter HSDPAServCellWindow value should be set carefully, below is analysis which shows the impact of delaying the SCC too much or advancing it too much (analysis only takes 2 cells into account)

)_(_ // ellWindowHSDPAServCcellBestCPICHcellServCPICH NoEcNoEc

Preferable SCC execution area is achieved with HSDPAServCellWindow = 2dB

Also HSDPACPICHEcNoThreshold = -5dB means that there is no other cell interefrence present at all (assuming CPICH power 2W CCCH power 2W and HSDPA power 6W, the best possible CPICH Ec/No would be ~-7dB) -> -5dB includes nicely some measurement inaccuracies (spec allows +/- 3dB)

Wei Yun

SCC = serving cell change


HSDPA Serving Cell Change – Impact of Other & Own Cell Interference

Clarifications of graph in previous slide

0

105

40...20

__

__

_

dBedgecell

dBmedgecell

dBfactor

G

RSCP

G

2_

6_

299_

2_

W

W

W

W

CCCHPtx

HSDPAPtx

trafficRPtx

CPICHPtx

_min-_maxminGmaxG

minG_min-_max

minGmaxGG

_min

_max

minG

maxG

factor-G on based

dBdB

dBdBdB

dB

G

dB

dB

dB

__

___

3.0

96.0

20_

50_

min

GRSCPCPICHPtxotherPL

:PL cell other

GRSCPCPICHPtxownPL

:PL cell own

factor-G of function a as athLossP

dBmedgecelldBmdB

dBmedgecelldBmdB

__

__

__

__


HSDPA Serving Cell Change – Impact of Other & Own Cell InterferenceClarifications of graph in previous slide

WGW

WWW

WW

WWWWG

own_G

NOownPL

trafficRPtxCCCHPtxCPICHPtx

NOownPL

HSDPAPtxtrafficRPtxCCCHPtxCPICHPtx

easeEc/No_decr

cell own in HSDPA to due decrease Ec/No

dB

dB

1_

99____

_99___1

factor

WW

WWW

WW

WWWW

other_G G

NOotherPL

trafficRPtxCCCHPtxCPICHPtx

NOotherPL

HSDPAPtxtrafficRPtxCCCHPtxCPICHPtx

easeEc/No_decr

cell other in HSDPA to due decrease Ec/No

_

99____

_99___1

dBowndBtotaldBother

dBotherdBowndBtotal

decreaseNoEcdecreaseNoEcdecreaseNEc

decreaseNoEcdecreaseNoEcdecreaseNoEc

___

___

_/_/_/

_/_/_/



Periodical CPICH Ec/No measurement are started only if the size of the active set is greater than one

If the size of the active set is one, periodical CPICH Ec/No reporting are not started / if running are stopped

RRC: MEASUREMENT CONTROL message is used for starting and stopping of the CPICH Ec/No measurement

Periodical CPICH Ec/No measurement is not possible to switch off by operator, but the measurement is always active


In order to execute inter-BTS serving the HS-DSCH cell change triggered by CPICH Ec/No measurements, the UL SIRerror of the target BTS must be above the threshold determined by the parameter HSDPASIRErrorTargetCell (def -2dB, typically used values -6dB) this has to be set according to HSDPASIRErrorServCell (def -3dB, typically used values -7dB)

• SIRerror measurement to be utilised for evaluation is the latest averaged value

• In the case of intra-BTS serving HS-DSCH cell change, UL SIRerror needs not to be checked

• If UL SIRerror measurement of the target cell has not been received by RNC, handover control executes serving HS-DSCH cell change triggered by DL CPICH Ec/No without taking UL SIRerror measurement into account, i.e. missing UL SIRerror measurement does not prevent serving HS-DSCH cell change

• It is possible to switch off usage of the UL SIRerror measurement by setting the reporting interval to 0

• In this case, HS-DSCH allocation is executed without taking UL SIRerror into account

More about SIRerror measurements, check HSDPA Serving Cell Change – UL SIRerror Measurement


Wei Yun

SIRerror check only for inter Node B


HSDPA power allocation shall also affect the selection of the serving HS-DSCH cellAll the HSDPA-capable cells, which fulfil the following condition, are selected as possible candidate cells for new serving HS-DSCH cells

• CPICHEc/NoBest_cell is the CPICH Ec/No measurement of the best cell in the active set

• CPICHEc/NoCell is the CPICH Ec/No measurement of the candidate • HSDPAServCellWindow is the management parameter , which determines the

window - relative to the best cell in the active set - inside of which the serving HS-DSCH cell must be in order to allocate HS-DSCH




When the cells, which fulfil the DL CPICH Ec/No and UL SIRerror conditions - as specified in the previous slide – are found, the serving HS-DSCH selection is executed according to the following priorities:1.The cell, which has already HSDPA power allocated is chosen as the serving

HS-DSCH cell– If several cells fulfil the criterion, DL CPICH Ec/No determines the order of the cells

2.The cell, which has the best DL CPICH Ec/No is chosen as the serving HS-DSCH cell

3.The cell, which has the next best DL CPICH Ec/No is chosen as the serving HS-DSCH cell

Note that in order to execute serving HS-DSCH cell change and allocate HS-DSCH at the target cell, channel type selection algorithm, must be successful, i.e. Cell/BTS must fulfill all the criteria regarding HS-DSCH allocationIf none of the cells in the active set can be chosen as serving HS-DSCH cell, i.e. serving HS-DSCH cell change cannot be executed, the current HS-DSCH allocation is kept



HSDPA Serving Cell Change - Failure in the Selection of Serving Cell in the Serving HS-DSCH Cell ChangeFailure in allocation of Iub AAL2 or RNC internal resources:

• When the target cell for serving HS-DSCH cell change has been chosen and if the reservation of the RNC internal resources or Iub AAL2 for the MAC-d flow fails, other possible candidate cells are attempted

• If similar failure occurs also for other candidate cells, serving HS-DSCH cell change is not executed

• If the current serving HS-DSCH cell cannot be kept, e.g. due to low UL SIRerror or lost radio link, HS-DSCH shall be released and RB mapped to DCH 0/0

Failure in RL reconfiguration:

• If the BTS with the serving HS-DSCH cell does not accept RL reconfiguration request and it returns some other general cause code than ‘Bearer re-arrangement needed', then serving HS-DSCH cell selection is interrupted

• If some other BTS than BTS with serving HS-DSCH cell does not accept RL reconfiguration request, then possible other candidates for serving HS-DSCH cell are tried to be selected

• If the serving HS-DSCH cell selection is interrupted or new cell can not be found, then current serving HS-DSCH cell is kept or HS-DSCH is released and RB mapped to DCH 0/0 (depending on handover reason)


Cell DCH – HS-DSCH -> HS-DSCH ->Cell ChangeDue to Periodical Ec/No

MeasurementsDue to Periodical Ec/No

Measurements

UE RNC SGSNNode B 1

HSDPA Traffic


Node B 2

UL-DCCH-Message {


messageAuthenticationCode '11010001000110111110010011011001'B,

rrc-MessageSequenceNumber 4 },

message measurementReport : {


measuredResults intraFreqMeasuredResultsList : {

{ cellSynchronisationInfo {


countC-SFN-Frame-difference {

countC-SFN-High 0,

off 4 },

tm 7681 } },


primaryCPICH-Info {

primaryScramblingCode 256 },

cpich-Ec-N0 37 } },

{cellSynchronisationInfo {



countC-SFN-High 0,

off 137 },

tm 14429 } },


primaryCPICH-Info {


cpich-Ec-N0 29 } },

{ cellSynchronisationInfo {



countC-SFN-High 0,

off 247 },

tm 36469 } },


primaryCPICH-Info {


cpich-Ec-N0 24 } } },

eventResults intraFreqEventResults : {

eventID e1a,

cellMeasurementEventResults fdd : {

{ primaryScramblingCode 297

} } },

v390nonCriticalExtensions {

measurementReport-v390ext { },

laterNonCriticalExtensions {

v4b0NonCriticalExtensions {

measurementReport-v4b0ext { },

v590NonCriticalExtensions {

measurementReport-v590ext {

measuredResults-v590ext intraFrequencyMeasuredResultsList : {

{ }, { }, { } } } } } } } } }


Cell DCH – HS-DSCH -> HS-DSCH ->Cell ChangeUE RNC SGSNNode B 1

HSDPA Traffic



Node B 2



DL-DCCH-Message {




}, message activeSetUpdate : r3 : {

activeSetUpdate-r3 {


maxAllowedUL-TX-Power 24,

rl-AdditionInformationList {

{ primaryCPICH-Info {


dl-DPCH-InfoPerRL fdd : {

pCPICH-UsageForChannelEst mayBeUsed,

dpch-FrameOffset 56,

dl-ChannelisationCodeList {

{ sf-AndCodeNumber sf256 : 12 } },

tpc-CombinationIndex 1 },

tfci-CombiningIndicator FALSE

} } } } }

Normal RL Setup, setting up RL with:

UL SF 16 (64kbps service) and

DL SF 256 and channelisation code 12

Due to Periodical Ec/No Measurements




HSDPA Traffic



Node B 2



NBAP: Radio Link Reconfiguration Commit:

CFN for the change to be taken into use: 252






NBAP: Radio Link Reconfiguration Prepare:

Modifying the HS DSCH (HS-DPCCH in SHO for better ACK/NACK and CQI detection):

CQI Power Offset = 7 -> Delta CQI 4dB

ACK Power Offset = 7 -> Delta ACK 4dB

Nack Power Offset =7 -> Delta NACK 4dB





HSDPA Traffic



Node B 2









DL-DCCH-Message {




}, message physicalChannelReconfiguration : later-than-r3 : {


criticalExtensions criticalExtensions-r4 : r5 : {

physicalChannelReconfiguration-r5 {

activationTime 252,

rrc-StateIndicator cell-DCH,

ul-ChannelRequirement ul-DPCH-Info : {

ul-DPCH-PowerControlInfo fdd : {

dpcch-PowerOffset -48,

pc-Preamble 0,

sRB-delay 7,

powerControlAlgorithm algorithm1 : 0,

deltaACK 7,

deltaNACK 7 },


scramblingCodeType longSC,

scramblingCode 1290484,

numberOfDPDCH 1,

spreadingFactor sf16,

tfci-Existence TRUE,

puncturingLimit pl0-68 } },

modeSpecificInfo fdd : { },

dl-HSPDSCH-Information {

measurement-feedback-Info {


measurementPowerOffset 9,

feedback-cycle fc4,

cqi-RepetitionFactor 1,

deltaCQI 7 } },

modeSpecificInfo fdd : NULL

} } } } }





HSDPA Traffic



Node B 2









DL-DCCH-Message {




}, message measurementControl : later-than-r3 : {


criticalExtensions r4 : {

measurementControl-r4 {


measurementCommand setup : intraFrequencyMeasurement : {

intraFreqMeasQuantity {

filterCoefficient fc3,


intraFreqMeasQuantity-FDD cpich-Ec-N0 } },

intraFreqReportingQuantity {

activeSetReportingQuantities {

dummy noReport,



RRC: Measurement Control modeSpecificInfo fdd : {

cpich-Ec-N0-reportingIndicator TRUE,


pathloss-reportingIndicator FALSE } },

monitoredSetReportingQuantities {

dummy noReport,




cpich-Ec-N0-reportingIndicator FALSE,


pathloss-reportingIndicator FALSE } } },

reportCriteria periodicalReportingCriteria : {

periodicalReportingCriteria {

reportingInterval ril0-5

}, reportingCellStatus withinActiveSet : e3 } },

measurementReportingMode {

measurementReportTransferMode acknowledgedModeRLC,

periodicalOrEventTrigger periodical } },

v4d0NonCriticalExtensions {

v590NonCriticalExtensions-r5 {

measurementControl-v590ext {

rrc-TransactionIdentifier-MSP-v590ext 1 } } } } } }

Setting up periodical Ec/No measurements for HS-DSCH serving cell change procedure

Periodical CPICH Ec/No measurement are started only if the size of the active set is greater than one. If the size of the active set is one, periodical CPICH Ec/No reporting is not started and if on going stopped





HSDPA Traffic



Node B 2














UL-DCCH-Message {




}, message measurementReport : {



{ modeSpecificInfo fdd : {

primaryCPICH-Info {

primaryScramblingCode 256

}, cpich-Ec-N0 37 } },


primaryCPICH-Info {


cpich-Ec-N0 27 } } },



}, laterNonCriticalExtensions {


measurementReport-v4b0ext {

}, v590NonCriticalExtensions {



{ }, { } } } } } } } } }

Periodical Measurement Reports




Cell DCH – HS-DSCH -> HS-DSCH ->Cell ChangeUL-DCCH-Message {




}, message measurementReport : {




primaryCPICH-Info {


}, cpich-Ec-N0 37 } },


primaryCPICH-Info {


cpich-Ec-N0 27 } } },



}, laterNonCriticalExtensions {


measurementReport-v4b0ext {

}, v590NonCriticalExtensions {



{ }, { } } } } } } } } }

Periodically reported DL CPICH Ec/No measurement results are averaged in RNC

HSDPACPICHAveWindow is RNC specific management parameter, which defines how many CPICH Ec/No measurements, which are received in the RRC: MEASUREMENT REPORT message, are included in the sliding window used in the averaging

RNC starts the averaging already from the first measurement sample (so the Serving cell change is possible after just one measurement report), that is, the RNC calculates the averaged values from those measurement samples which are available until the number of measurement samples is adequate to calculate averaged values over the whole averaging window





HSDPA Traffic



Node B 2















Old BTS to delete the HS-DSCH user (MAC-d flow) and

to new BTS to set up the HS-DSCH (MAC-d flow) with

CQI Power Offset = 7 -> Delta CQI 4dB

ACK Power Offset = 7 -> Delta ACK 4dB

Nack Power Offset =7 -> Delta NACK 4dB








HSDPA Traffic



Node B 2
















ALCAP : ERQ


ALCAP : ECF


NBAP: Radio Link Reconfiguration Commit for both BTSs

to inform the CFN when the HS-DSCH serving cell change will be taken into use.

CFN 148





HSDPA Traffic



Node B 2
















ALCAP : ERQ


ALCAP : ECF


DL-DCCH-Message {




}, message radioBearerReconfiguration : later-than-r3 : {


criticalExtensions criticalExtensions-r4 : r5 : {

radioBearerReconfiguration-r5 {

activationTime 148,

new-H-RNTI '1001101111001111'B,

rrc-StateIndicator cell-DCH,

specificationMode complete : {

dl-AddReconfTransChInfoList {

{ dl-TransportChannelType hsdsch : NULL,

tfs-SignallingMode hsdsch : {

addOrReconfMAC-dFlow {

mac-hs-AddReconfQueue-List {

{ mac-hsQueueId 0,

mac-dFlowId 0,

reorderingReleaseTimer rt120,

mac-hsWindowSize mws16

} } } } } } },

modeSpecificPhysChInfo fddphch : {

}, dl-CommonInformation {


}, mac-hsResetIndicator true

}, dl-InformationPerRL-List {


primaryCPICH-Info {


}, servingHSDSCH-RL-indicator TRUE

}, dl-DPCH-InfoPerRL fdd : {

pCPICH-UsageForChannelEst mayBeUsed,

dpch-FrameOffset 56,

dl-ChannelisationCodeList {

{ sf-AndCodeNumber sf256 : 12 } },

tpc-CombinationIndex 1

} } } } } } }RRC: Radio Bearer Reconfiguration





HSDPA Traffic



Node B 2















ALCAP : ERQ


ALCAP : ECF


RRC: Radio Bearer Reconfiguration

RRC: Radio Bearer Reconfiguration Complete (DCH)



ALCAP : Release RequestALCAP : Release Confirm


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – UL SIRerror Measurement Triggered

It is possible to switch off usage of the UL SIRerror measurement by setting the reporting interval to 0

• In this case, HS-DSCH allocation is executed without taking UL SIRerror into account

• In this case, serving HS-DSCH cell change due to UL SIRerror is not allowed

When BTS reports periodical dedicated UL SIRerror measurement, need for the serving HS-DSCH BTS change is evaluated

If UL SIRerror measurement of the serving cell is not received by RNC, HS-DSCH allocation is not interrupted but the handover control applies other available triggers for the serving HS-DSCH cell change procedure

If SIRerror of the current serving HS-DSCH BTS is below the threshold determined by the parameter HSDPASIRErrorServCell (def -3dB, typically used value -7dB), serving HS-DSCH BTS change is initiated

Wei Yun

not a must that target cell SIR is better, it can also be triggered if serving cell SIR is poor


HSDPA Serving Cell Change – UL SIRerror Measurement TriggeredThe new serving HS-DSCH cell is chosen as follows:

• DL CPICH Ec/No and UL SIRerror are used as criteria

• Note that CPICH Ec/No of the candidate cell does not have to fulfil equation below i.e. it does not have to be inside of the window in order to allocate HS-DSCH (this means that SCC due to UL SIRerror can change the HSDPA Service Cell to non optimal cell – in DL direction)

• The CPICH Ec/No and UL SIRerror measurements to be used for evaluation are taken from the latest averaged value of periodical measurement reports from UE and BTS

• UL SIRerror of the target cell must be above or equal to the threshold determined by the parameter HSDPASIRErrorTargetCell (def -2dB, typically used value -6dB) in order to allocate HS-DSCH, i.e. the target cell fulfills the following condition:

– ,where SIRerrorBTS is the SIRerror measurement of the candidate BTS and HSDPASIRErrorTargetCell is the threshold, which SIRerror of the candidate BTS must fulfill


)ellrorTargetCHSDPASIRer BTSSIRError


HSDPA Serving Cell Change – UL SIRerror Measurement Triggered

If UL SIRerror measurement of the target cell has not been received by RNC, handover control excludes this particular cell from the candidate list of the serving HS-DSCH cell change procedure triggered by UL SIRerror measurement of the serving cell

When the cells, which fulfil the UL SIRerror condition are found, the serving HS-DSCH selection is executed according to the following priorities:

1. The cell, which has already HSDPA power allocated is chosen as the serving HS-DSCH cell

– If several cells fulfil the criterion, DL CPICH Ec/No determines the order of the cells


3. The cell, which has the next best DL CPICH Ec/No is chosen as the serving HS-DSCH cell

Note that in order to execute serving HS-DSCH cell change and allocate HS-DSCH at the target cell, channel type selection algorithm must be successful, i.e. Cell/BTS must fulfill all the criteria regarding HS-DSCH allocation

If the cell, which fulfils the condition specified above cannot be found, HS-DSCH is released an switch to DCH 0/0 kbps executed


Contents

HS-DSCH AC














• ISHO with SCC

Wei Yun

periodic SIR report can only be seen in Iub


HSDPA Serving Cell Change – UL SIRerror Measurement

UL SIRerror measurement is used as a criterion for serving HS-DSCH cell change

UL SIRerror can also initiate release of the HS-DSCH

After HS-DSCH is allocated to the UE, periodical UL SIRerror measurement is started

Dedicated UL SIRerror measurement is applied to the selection of the serving HS-DSCH cell and it is also used as criterion for a sufficient UL quality for HS-DPCCH transmission

Reporting is periodical, except when measurement report is filtered in BTS

Reporting criteria of the dedicated UL SIRerror measurement is determined in the following way

• Dedicated measurement type is SIRerror

• Dedicated measurement object type is ALL RLS



Measurement filter coefficient is determined by the RNP-parameter HSDPASIRErrorFilterCoefficient

• The parameter determines the value of filtering coefficient to be used in higher layer filtering of the measurement result

• The filter coefficient parameter controls the higher layer filtering of physical layer UL SIRerror measurements before measurement reporting is performed by the BTS

• The approximated weight of the latest measurement result with the different values of the parameter is as follows: Value (Weight): 0 (100%), 1 (71%), 2 (50%), 3 (35%), 4 (25%), 5 (18%), 6 (13%), 7 (9%), 8 (6%), 9 (4%), 11 (2%)

• Higher layer filtering has been specified in the 3GPP TS 25.433 – “The Measurement Filter Coefficient IE indicates how filtering of the measurement values shall be performed before measurement

event evaluation and reporting.

– The averaging shall be performed according to the following formula.

– The variables in the formula are defined as follows:

– Fn is the updated filtered measurement result

– Fn-1 is the old filtered measurement result

– Mn is the latest received measurement result from physical layer measurements, the unit used for Mn is the same unit as the reported unit in the COMMON MEASUREMENT INITIATION RESPONSE, COMMON MEASUREMENT REPORT messages or the unit used in the event evaluation (i.e. same unit as for Fn)

– a = ½^(k/2) , where k is the parameter received in the Measurement Filter Coefficient IE. If the Measurement Filter Coefficient IE is not present, a shall be set to 1 (no filtering)

– In order to initialise the averaging filter, F0 is set to M1 when the first measurement result from the physical layer measurement is received”

nnn MaFaF 1)1(


HSDPA Serving Cell Change – UL SIRerror Measurement• The SIRerror measurements are specified in the TS 25.433, 25.133 and 25.215

– 25.133: ▪ The measurement period is 80 ms

▪ NOTE: The measurement period is the same as for the SIR measurement, SIRerror is calculated from SIR and SIRtarget (SIRerror = SIR – SIRtarget_ave )

▪ The reporting range for SIRerror is from -31 ... 31 dB

▪ In table 9.39 the mapping of measured quantity is defined. The range in the signalling may be larger than the guaranteed accuracy range.

Parameter Accuracy Range

SIRerror 3 dB The accuracy requirement for SIRerror is valid for SIR within the guaranteed accuarcy range specified in section 9.2.2.

Conditions Parameter Unit Accuracy [dB]

Range SIR dB 3 For -7<SIR<20 dB when

Iob > -105 dBm/3.84 MHz

Reported value Measured quantity value Unit UTRAN_SIR_00 SIR < -11.0 dB UTRAN_SIR_01 -11.0 SIR < -10.5 dB UTRAN_SIR_02 -10.5 SIR < -10.0 dB … … … UTRAN_SIR_61 19.0 SIR < 19.5 dB UTRAN_SIR_62 19.5 SIR < 20.0 dB UTRAN_SIR_63 20.0 SIR dB


HSDPA Serving Cell Change – UL SIRerror Measurement• Report characteristics is periodic

– The report periodicity is determined by the RNP-parameter HSDPASIRErrorReportPeriod (def. 0.5s)

NBAP: Dedicated Measurement Initiation procedure is used for starting and stopping of the UL SIRerror measurement

Periodical UL SIRerror reporting is possible to switch off by operator by setting the reporting interval to 0 with the management parameter HSDPASIRErrorReportPeriod

• If reporting is switched off, UL SIRerror is used as a criterion for neither serving HS-DSCH cell change nor HS-DSCH release


SIRerror is the difference between the SIRtarget used in the BTS for Fast Closed Loop PC and and the actual measured SIR as follows:

SIRerror = SIR – SIRtarget_ave

• where:SIR is the SIR measured by the BTS and SIRtarget_ave is the SIRtarget averaged over the same time period as the SIR used in the SIRerror calculation

• SIRerror measurement is specified in TS 25.215

From 25.215

“Signal to Interference Ratio, is defined as: (RSCP/ISCP)SF. The measurement shall be performed on the DPCCH of a Radio Link Set. In compressed mode the SIR shall not be measured in the transmission gap. The reference point for the SIR measurements shall be the Rx antenna connector. If the radio link set contains more than one radio link, the reported value shall be the linear summation of the SIR from each radio link of the radio link set. If Rx diversity is used in the Node B for a cell, the SIR for a radio link shall be the linear summation of the SIR from each Rx antenna for that radio link. When cell portions are defined in the cell, the SIR measurement shall be possible in each cell portion.

• where:– RSCP = Received Signal Code Power, unbiased measurement of the received power on one code.

– ISCP = Interference Signal Code Power, the interference on the received signal.

– SF=The spreading factor used on the DPCCH.”




Periodically reported UL SIRerror measurement results are averaged in RNC

HSDPASIRErrorAveWindow (def. 3) is RNC specific management parameter, which defines how many SIRerror measurements, which are received in the NBAP: DEDICATED MEASUREMENT REPORT message, are included in the sliding window used in the averaging. SIRerror is averaged using the following formula:

• Where SIRError (t) is the latest received SIRError measurement and n equals to HSDPASIRErrorAveWindow

RNC starts the averaging already from the first measurement sample, that is, the RNC calculates the averaged values from those measurement samples which are available until the number of measurement samples is adequate to calculate averaged values over the whole averaging window

RNC calculates the averaged values directly from the measured dB values, linear averaging is not used in this case

n

ntSIRtSIRtSIRSIR ErrorErrorError

Error))1((...)1()(


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – Event 1B Triggered

Intra-frequency measurement event 1B (A primary CPICH leaves the reporting range) initiates serving HS-DSCH cell change if the cell to be removed from the active set is the serving HS-DSCH cell

Active set update is delayed until either serving HS-DSCH cell change or HS-DSCH release (switch to DCH 0/0) has been performed

DL CPICH Ec/No and UL SIRerror are used as criteria

• Note that CPICH Ec/No of the candidate cell does not have to fulfil equation below i.e. it does not have to be inside of the window in order to allocate HS-DSCH




DL CPICH Ec/No measurements used for the selection of the new serving HS-DSCH cell are taken from the reported measurement event 1B

• If, for some reason, CPICH Ec/No measurement results of all the active set cells are not available in the measurement event 1B, the latest averaged value of periodical CPICH Ec/No measurement report is used

The new serving HS-DSCH cell is chosen as follows:

UL SIRerror of the target cell must be above or equal to the threshold determined by the parameter HSDPASIRErrorServCell in order to allocate HS-DSCH

• If UL SIRerror measurement of the target cell has not been received by RNC, handover control execute serving HS-DSCH cell change triggered by measurement event 1B without taking UL SIRerror measurement into account, i.e. missing UL SIRerror measurement does not prevent serving HS-DSCH cell change








Note that in order to execute serving HS-DSCH cell change and allocate HS-DSCH at the target cell, channel type selection algorithm, must be successful, i.e. Cell/BTS must fulfill all the criteria regarding HS-DSCH allocation

If a new serving HS-DSCH cell cannot be found, HS-DSCH is released and RB is mapped to DCH 0/0


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – Event 1C Triggered

Intra-frequency measurement event 1C (A non-active primary CPICH becomes better than an active one) initiates serving HS-DSCH cell change if the cell to be removed from the active set is the serving HS-DSCH cell

Active set update is delayed until either serving HS-DSCH cell change or HS-DSCH release (switch to DCH 0/0) has been performed


• Note that CPICH Ec/No of the candidate cell does not have to fulfil equation below i.e. it does not have to be inside of the window in order to allocate HS-DSCH




DL CPICH Ec/No measurements used for the selection of the new serving HS-DSCH cell are taken from the reported measurement event 1C

• If, for some reason, CPICH Ec/No measurement results of all the active set cells are not available in the measurement event 1C, the latest averaged value of periodical measurement CPICH Ec/No measurement report is used.

The new serving HS-DSCH cell is chosen as follows:


• If UL SIRerror measurement of the target cell has not been received by RNC, handover control executes serving HS-DSCH cell change triggered by measurement event 1C without taking UL SIRerror measurement into account, i.e missing UL SIRerror measurement does not prevent serving HS-DSCH cell change









If a new serving HS-DSCH cell cannot be found, HS-DSCH is released and RB is mapped to DCH 0/0


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – Removal of Radio Link TriggeredThe following reasons, which may cause removal of the radio link from the active set initiate serving HS-DSCH cell change:

RL failure of the serving HS-DSCH radio link (loss of UL synchronisation)

• If BTS sends NBAP: RADIO LINK FAILURE message (loss of UL synchronisation) to RNC regarding the current serving HS-DSCH radio link and there are other HSDPA-capable cells in the active set, the serving HS-DSCH cell change is executed

Serving HS-DSCH radio link is handed over to DRNC

• If the current serving HS-DSCH radio link is handed over to DRNC, and there are other HSDPA-capable cells under SRNC in the active set, the serving HS-DSCH cell change is executed

• The candidate cell must be located under SRNC in order to execute serving HS-DSCH cell change

RL removal due to Rx-Tx time difference

• If the current serving HS-DSCH radio link is deleted from the active set due to Rx-Tx time difference measurement (Event 6F, 6G), and there are other HSDPA-capable cells in the active set, the serving HS-DSCH cell change is executed


HSDPA Serving Cell Change – Removal of Radio Link TriggeredThe new serving HS-DSCH cell shall be chosen as follows:


Note that CPICH Ec/No of the candidate cell does not have to fulfil equation below i.e. it does not have to be inside of the window in order to allocate HS-DSCH

The CPICH Ec/No and UL SIRerror measurements to be used for evaluation are taken from the latest averaged value of periodical measurement reports from UE and BTS


If UL SIRerror measurement of the target cell has not been received by RNC, handover control executes serving HS-DSCH cell change triggered by removal of the radio link without taking UL SIRerror measurement into account, i.e. missing UL SIRerror measurement does not prevent serving HS-DSCH cell change



HSDPA Serving Cell Change – Removal of Radio Link Triggered







If a new serving HS-DSCH cell cannot be found, HS-DSCH shall be released and RB is mapped to DCH 0/0


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – Too Frequent Serving Cell ChangesFrequent serving HS-DSCH cell changes initiate HS-DSCH release and switching to DCH

The number of successful serving HS-DSCH cell changes due to any reason is counted

• If the number of serving HS-DSCH cell changes, determined by the parameter HSDPAMaxCellChangeRepetition (def. 4), in a time period determined by the parameter HSDPACellChangeRepetitionTime (def. 10s), is exceeded, HS-DSCH is released and RB is mapped to DCH 0/0

• HSDPACellChangeRepetitionTime determines a window in seconds during which calculation is made

• Window is moved forward once per second with a step size of one second


Contents

HS-DSCH AC














• ISHO with SCC


HSDPA Serving Cell Change – Existence with ISHO/IFHOInter System and Inter Frequency handovers can be triggered as with R99 DCH via event triggered measurement reports 1F or event 6A or UL Quality Deterioration report received by RNC

• HS-DSCH is released and DCH is allocated instead

• On DCH then the compressed mode can be started

Service HSDPAmobility disabled HSDPAmobility enabled

Measurement Single NRT PS RAB AMR multi-service Single NRT PS RAB AMR multi-service

Event 1E (CPICH Ec/No)

Cancel event 1F Cancel event 1F Cancel event 1F Cancel event 1F

Event 1E (RSCP)

Cancel event 1F Cancel event 1F Cancel event 1F Cancel event 1F

Event 1F (CPICH Ec/No)

Release HS-DSCH (switch to DCH 0/0)


and start IFHO/ISHO measurements



and start IFHO/ISHO

measurements

Event 1F (RSCP)






and start IFHO/ISHO

measurements

DL Tx code power

Ignore (not relevant) Release HS-DSCH (switch to DCH 0/0)


Ignore (not relevant) Release HS-DSCH (switch to DCH 0/0)

and start IFHO/ISHO

measurements

Event 6A (UE Tx power)





Event 6B (UE Tx power)

Cancel event 6A Cancel event 6A Cancel event 6A Cancel event 6A

UL DCH quality deterioration





193219515 hsdpa-performance-improvement-discussion-nsn-20070518

Engineering