06 RN31576EN30GLA0 Capacity Enhancement

Confidential 1 © Nokia Siemens Networks RN31576EN30GLA0

Capacity Enhancement3G RANOP RU30


Course Content

KPI overviewPerformance monitoringAir interface optimizationTraffic MonitoringCapacity Enhancement


Module ObjectivesAt the end of the module you will be able to:• Describe capacity enhancing R99 features

• Discuss the impact of R5 and R6 HSPA features on capacity

• Demonstrate the capacity enhancement potentials of HSPA features introduced with R7 and beyond


R99 Features

AMR

BLER target settings

Eb/No settings

Throughput based optimization

Maximum radio link power

4Rx diversity

HSDPA

HSUPA

HSDPA+

HSUPA+

Capacity Enhancement


Voice calls performed as FR or HR calls in dependence on• Non controllable load on DL

• Code tree occupation

• Iub throughput

For each criterion there is a load indicator having three thresholds• Underload threshold

• Target threshold

• Overload threshold

FR call• Voice codec sample = {12.2/7.95/5.9/4.75} Kbit/s

• DL SF = 128 fixed

HR call• Voice codec sample = {5.9/4.75} Kbit/s

• DL SF = 128 or 256 in dependence on code tree occupation

AMR - Idea


AMR - Role of LoadLoad

Underload thresholdIf no load indicator exceeds underload threshold

New calls start as FR

Running HR calls automatically switched to FR

If no load indicator exceeds underload threshold


Running HR calls automatically switched to FR

At least one load indicator exceeds underload threshold

But no load indicator exceeds target threshold


Running HR calls remain HR

At least one load indicator exceeds underload threshold

But no load indicator exceeds target threshold


Running HR calls remain HR

Target threshold

At least one load indicator exceeds target threshold

But no load indicator exceeds overload threshold

New calls start as HR

Running FR calls remain FR

At least one load indicator exceeds target threshold

But no load indicator exceeds overload threshold


Running FR calls remain FR

Overload threshold

If one load indicator exceeds overload threshold


Running FR calls automatically switched to HR

If one load indicator exceeds overload threshold


Running FR calls automatically switched to HR


AMR - Role of LoadLoad thresholds for non controllable load on DL

• Set relative to PtxTarget (default 40 dBm)

• AMRUnderTxNc (default -10 dB)

• AMRTargetTxNc (default -2 dB)

• AMROverTxNc (default -1 dB)

Load thresholds for code tree occupation

• AMRUnderSC (default 50%)

• AMRTargetSC (default 70%)

• AMROverSC (default 90%)

Load thresholds for Iub throughput

• AMRUnderTransmission (default 200 Kbit/s)

• AMRTargetTransmission (default 800 Kbit/s)

• AMROverTransmission (default 900 Kbit/s)


AMR - Selection of SF for HR Calls

AMRSF set relative to maximum allowed RL power determined by AC (default -2 dB)In case of high RL power SF128 (NOT SF256) better for voice transmission due to DPCCH overhead


For R99 bearers the operator can define the BLER target controlled by outer loop power control

Strict BLER target (low BLER)• Little throughput degradation and delay by re-transmission → good quality for user

• But higher Eb/No needed → higher power consumption per radio link

Less strict BLER target (high BLER)• Strong throughput degradation and delay by re-transmission → bad quality for user

• But less Eb/No needed → lower power consumption per radio link

BLER Target Settings - Idea


BLER target can be defined for the following services• SRB of 3.4 and 13.6 Kbit/s (EbNoDCHOfSRB34/136Qua, default 1%)

• Narrowband and wideband AMR (EbNoDCHOfCSN/WBAMRQua, default 1%)

• Streaming service

• NRT service

In case of streaming and NRT service one can define two BLER targets• Strict target for low bit rate up to 64 Kbit/s (EbNoDCHOfPSStr/NRTPriQua, default = 1%)

• Less strict target for high bit rate > 64 Kbit/s (EbNoDCHOfPSStr/NRTSecQua, default = 5%)

• One can select per bit rate, which of the two BLER targets shall be used

BLER Target Settings - Role of Service


BLER Target Settings - Example

Consider DL bearer with 256 Kbit/s

Default target 5%Pedestrian → Eb/No = 3.6 dBFast vehicle → Eb/No = 7.3 dB

Less strict target 10%Pedestrian → Eb/No = 3.4 dB (0.2 dB gain)Fast vehicle → Eb/No = 6.9 dB (0.4 dB gain)

Source

J.J. Olmos, S.Ruiz, Transport Block Error Rates for UTRA FDD

Downlink with Transmission Diversity and Turbo Coding

In Proc. IEEE 13th PIMRC 2002, vol.1, pp 31-35, Sept. 2002.


BLER Target Settings - Example

RW

NEi b

DL /

/])1[( 0

Consider load factor for previous example in typical macro cell• Orthogonality α = 0.6

• Adjacent to own cell interference ratio i = 0.6

Consider activity factor = 1 for NRT service

5% BLER target

• 15.3% load for pedestrian

• 35.8% load for fast vehicle

10% BLER target

• 14.6% load for pedestrian (0.7% gain)

• 32.7% load for fast vehicle (3.1% gain)

Small capacity gain obtained with less strict BLER target only especially for slow moving user


For R99 and HSUPA bearers the operator can define Eb/No values as well• Eb/No settings cannot be treated as independent configuration, as Eb/No affects BLER

• Eb/No settings offered by NSN applied to initial radio link power only

• Afterwards Eb/No adjusted by outer loop power control to follow BLER target

• Thus Eb/No settings affect setup and access only, but not load in the network

High initial Eb/No• High initial radio link power → high blocking probability

• But low initial BLER → low risk of drop during initial phase

Low initial Eb/No• Low initial radio link power → low blocking probability

• But high initial BLER → high risk of drop during initial phase

Eb/No Settings - Restrictions


The initial Eb/No can be defined for the following services• SRB of 3.4 and 13.6 Kbit/s (EbNoDCHOfSRB34/136, default 8 dB)

• AMR 12.2 and 5.9 Kbit/s (EbNoDCHOfCSN/BAMR122/59, default 8 dB)

• Streaming service

• NRT service

In case of streaming and NRT service one can define Eb/No in dependence on BLER target• Strict target (EbNoDCHOfPSStr/NRTPri, default = 8 dB)

• Less strict target (EbNoDCHOfPSStr/NRTSec, default = 6.5 dB)

For the following situations gain factors can be specified• Receive diversity (EbNoDCHRxDiv2/4, default 3 and 4 dB gain for 2 and 4 Rx diversity)

• Rate matching (one parameter for each type of service, up to 2 dB gain for effective coding rate < 1:3)

Eb/No Settings - Role of Service


Consider initial radio link power in typical macro cell• Total power = 10 Watt

• CPICH power = 2 Watt

• Ec/Io = -10 dB

• Orthogonality α = 0.6

• R = 256 Kbit/s

5% BLER initially (Eb/No = 3.6 and 7.3 dB)

• 2.1 W power for pedestrian

• 5.0 W power for fast vehicle

10% BLER initially (Eb/No = 3.4 and 6.9 dB)

• 2.0 W power for pedestrian (0.1 W gain)

• 4.6 W load for fast vehicle (0.4 W gain)

Eb/No Settings - Example

rtotal_powerCPICH_powe

0

01

__I

E

NE

c

b

W

RpowerRLInitial

Small power gain obtained with less strict initial BLER only especially for slow moving user


Consider NRT DCH of low utilization• Inactivity timers do not expire in case of frequent transmission of small packets

• Huge amount of resources might be reserved unnecessarily • Code of low SF (blocks many codes of high SF)

• Channel elements

• Iub resources

Throughput based optimization• Downgrade DCH to lower level in this case

• Can be enabled for each NRT traffic class individually• Inactive with traffic handling priority 1/2/3

• Background

Throughput Based Optimization - Idea


Actual throughput suddenly drops

Consider throughput averaged over sliding window• Short window to react to strong drops

• Long window to react to moderate drops

Compare average throughput with thresholds• Downgrade upper threshold (long time to trigger)

• Downgrade lower threshold (short time to trigger)

• Release threshold (short time to trigger)

Throughput Based Optimization - Mechanism

Actual DCH level

Downgrade upper threshold

Default 2 levels below actual DCH

Downgrade upper threshold

Default 3 levels below actual DCH

Release threshold

Default 256 Bit/s

Actual throughput

Average – long window

Average – short window

Short time to triggger

Long time to triggger

Time

Throughput


Throughput Based Optimization - Example

AMR traffic → no impact, as not considered by featurePS traffic → about 1/3 less CE occupied in the average

Feature OFF Feature ON

Usage of channel elements




About 5% less resources reserved on Iub

Reservation of ATM resources on Iub




Due to lower resource reservation about 2/3 less blocking on Iub

Blocking on Iub


Throughput Based Optimization – Example


Less downgrades required due to• Preemption• Overload control• Dynamic link adaptation

But dramatic increase of downgrades due to TBOPing-Pong RB reconfiguration upgrade-downgrade• Define bigger guard timer against consecutive bit rate adaptations• Enable TBO for certain traffic classes only

Downgrade causes


Maximum Radio Link Power - MechanismMaximum radio link power set automatically by RNC

Three different thresholds based on different criteria• 1) Relative to maximum cell power (same threshold for any service)

• 2) Relative to CPICH power (corrected by SF adjustment in dependence on service)

• 3) Absolute threshold (for PS services)

Finally lowest threshold is used

PtxDPCHMax (Default 3 dB)

CPICHtoRefRABOffset (Default 2 dB)

PtxCellMax (Default 43 dBm)

Maximum RL power Criterion 1

PtxDLabsMax (Default 37 dBm)

PtxPSstreamAbsMax (Default 37 dBm)

PtxPrimaryCPICH (Default 33 dBm)

Maximum RL power Reference service (Default 12.2 Kbit/s voice) Criterion 2

SF adjustmentCalculated by RNC

Maximum RL power Any service Criterion 2

Maximum RL power PS service Criterion 3


Comparison of actual service with reference service based on• SF

• Eb/No

If several bearers are running simultaneously, all of them are taken into account

Examples• Reference service = voice → R = 12.2 Kbit/s, Eb/No = 7 dB

• Actual service PS → R = 64 Kbit/s, Eb/No = 7 dB

• Actual service PS → R = 384 Kbit/s, Eb/No = 5 dB

Results• 64K PS → SF adjustment = (100.7 * 64) / (100.7 * 12.2) = 5.2 = 7.2 dB

Maximum RL power = 33 dBm – 2 dB + 7.2 dB = 38.2 dBm

• 384K PS → SF adjustment = (100.5 * 384) / (100.7 * 12.2) = 19.9 = 13.0 dB

Maximum RL power = 33 dBm – 2 dB + 13.0 dB = 44.0 dBm

In both cases cutoff due to criterion 3 at 37 dBm

refref

CCTrCHDCHDCHDCH

REbNo

REbNoadjustmentSF

_

Maximum Radio Link Power – SF Adjustment


CPICHtoRefRABOffset• Maximum power of reference service relative to CPICH power

• Shifts all services to higher or lower maximum radio link power

• Low power for reference service• Low coverage in general

• But higher capacity, as no single user can take away too much power

• High power for reference service• High coverage in general

• But lower capacity, as single user can take away much power

PtxDLAbsMax / PtxPSstreamAbsMax• Maximum power of NRT / RT PS service

• Cutoff to avoid, that single user takes too much power

• Similar compromise between coverage and capacity needed as for CPICHtoRefRABOffset

Maximum Radio Link Power – Key Parameters


BTS

UE

384kbps 128kbps

distance

Maximum Radio Link Power – Dynamic Link Optimization

Radio link power comes close to maximum power• Reduce bit rate of NRT services by increasing SF

• Reduce bit rate of AMR voice service by taking more robust voice codec


time

Triggering of DyLO (Default = 35 dBm)

DLOptimisationPwrOffset (Default = 2 dB)


BTS measures power of each radio links and sends periodic report to RNC

RNC averages reports over settable sliding window (default 4 reports)

Dynamic link optimization triggered if

Average RL power > Maximum RL power - DLOptimisationPwrOffset

Average RL power

Maximum RL power (Default for PS = 37 dBm)


BTS

UE

384 K

distance


Dynamic link optimization not performed any more, if• Actual bit rate ≤ MinAllowedBitRateDL (Default 8 Kbit/s) OR

• Actual bit rate ≤ HHoMaxAllowedBitRateDL (Default 32 Kbit/s)

In the latter case HHO will be triggered instead

In case of AMR voice HHO will be triggered, if even with the most robust codec too much RL power is consumed

128 K64 K32 KHHO area


2 Rx diversity• Compensation of fast fading on the UL by usage of two receive paths

• Space diversity

– Horizontal separation (gain depends on azimuth)

– Vertical separation

• Polarization diversity

• Coverage gain on UL about 3 dB (less Eb/No and SIR target needed)

2-3 m

space

diversity

polarization

diversity

4Rx Diversity - Idea


4 Rx diversity• Enhanced compensation of fast fading on the UL by usage of four

receive paths• Combined space and polarization diversity (two cross-polarized antennas)

• Pure space diversity (four single-polarized antennas)

• Additional coverage gain against 2 Rx diversity around 1-3 dB (again less Eb/No and SIR target needed)

Combined space and polarization

diversity

Pure space

diversity

4Rx Diversity - Idea


• 4 Rx diversity can be realized together with the following features, defined by the following implementation phases• Phase 1 MIMO

• Phase 2 + Frequency domain equalizer

• Phase 3 + HSUPA Interference cancellation receiver

4Rx Diversity - Interoperability


RA

KE

At least two additional strong

signals on RAKE input

•2 additional antennas (one in case dual beam antenna)

•2 times more fibers and jumpers or feeders

4Rx Diversity – Impact on HW


Consider UE transmission power during drive test2Rx diversity → average UE power 4.4 dBm4Rx diversity → average UE power 1.6 dBmGain = 4.4 dBm – 1.6 dBm = 2.8 dB

Source

Antti Tölli and Harri Holma

Comparison of WCDMA UL antenna solutions with 4Rx branches

In: Proceedings of the CDMA International Conference (CIC), South Korea, 25-28 October 2000, pp. 57-61

4Rx Diversity – ExampleUE transmission power during drive test


Coverage enhancement

• 3dB gain in UL

• Area size 1000 km2

• Clutter type urban

• Output power 40W

32% less sites

2 Rx Diversity 4 Rx DiversityCell Range [km] 1.341 1.631Site-to-Site Distance [sqkm] 2.011 2.447Number of sites 857 579

Number of sites reduction could be reached only in UL

limited scenarios

Total Network Cost

0.00

0.20

0.40

0.60

0.80

1.00

1.20

2Rx Diversity 4Rx Diversity

-27%

Include:

• Lower number of sites

• 2x more number of antennas

4Rx Diversity – Example


Without feature With feature

Mean HSUPA throughput [kbps]

0

50

100

150

200

250

300

350

2Rx Diversity 4Rx Diversity

28%

• Active Users: 53

• Mean throughput: 248.7

• UL Power Outage: 4.79

• Active Users: 68

• Mean throughput: 318.5

• UL Power Outage: 4.44

Capacity enhancement

4Rx Diversity – Example


R99 Features

HSDPA

Fractional DPCH

Dynamic BLER

72 HSPA users per cell

HSUPA

HSDPA+

HSUPA+



Fractional DPCH - IdeaAvailable since RU20

Mapping of SRB on HS-DSCH, not on associated DCH

DPCH than needed for UL power control only → reduced to F-DPCH

Node B

RNCIub

HS-SCCH

HS-SCCHHS - DSCH

HS-PDSCH

HSUPA channels

HSUPA channels

F-DPCH

F-DPCH

HS-DPCCH

HS-DPCCH


Fractional DPCH - Mechanism

Data block 1 TPC TFCIoptional

Data block 2 PilotData block 1 TPC TFCIoptional

Data block 2 Pilot

1 Slot = 2/3 ms = 2560 chip

TPCF-DPCH slot: power control commands only

DPCH slot: full configuration

TX OFF TX OFF

SRB on associated DCH• Full configuration of DPCH needed

• Dedicated to single user

SRB on HS-DSCH• No data on DPCH any more

→ TFCI field not needed any more

• TPC used not only for power control, but also SIR measurements

→ pilot field not needed any more

• Can be shared by 10 users by time multiplex


Fractional DPCH - LimitationsFractional DPCH requires good performance on air interface• CPICH coverage better than CPICHRSCPThreSRBHSDPA (Default -103 dBm)

• CPICH quality better than CPICHECNOSRBHSPA (Default -6 dB)

Due to strict quality requirements fractional DPCH available only if• Low DL traffic

• Little adjacent cell interference (UE close to BTS)

BTS

UE F-DPCH

NormalDPCH

distance


Fractional DPCH - LimitationsFurther restriction if F-DPCH shall be setup in SHO area

Ec/Io of non serving cell must not exceed Ec/Io of serving cell by HSDPASRBWindow (Default 1 dB)

CPICH 1 = server

CPICH 2 = non server

EC/I0

time

HSDPASRBWindow

F-DPCH setup allowed Normal DPCH only


Fractional DPCH - DL Power ConsumptionConsider radio link power for SRB on associated DCH• Total power = 8 Watt (low DL power, as otherwise Ec/Io = -6 dB not fulfilled)

• CPICH power = 2 Watt

• Ec/Io = -6 dB

• Orthogonality α = 0.6

• R = 13.6 Kbit/s

• Eb/No = 8 dB

RL power = 0.071 W = 18.5 dBm

rtotal_powerCPICH_powe

0

01

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E

NE

c

b

W

RpowerRLInitial


Fractional DPCH - DL Power ConsumptionConsider radio link power for F-DPCH• No power control

• Static power set relative to CPICH with PtxFDPCHMax (Default 9 dB)

• In SHO area more power allocated according PtxOffsetFDPCHSHO (Default 1 dB)

RL power = 24 / 25 dBm outside / within SHO area• But shared among up to 10 users

• Effectively 14 / 15 dBm per user → gain of about 3-4 dB per user

PtxFDPCHMax (Default 9 dB)

PtxPrimaryCPICH (Default 33 dBm)

F-DPCH power outside SHO area (Default 24 dBm)

PtxOffsetFDPCHSHO (Default 1 dB)

F-DPCH power within SHO area (Default 25 dBm)


Fractional DPCH - Code and CE ConsumptionAssociated DCH (13.6 Kbit/s)• One SF128 per user → 72 x SF128 for 72 users → 9 codes with SF16 lost

• One CE per user → 72 CE for 72 users

F-DPCH• One SF256 per 10 users → 8 x SF256 for 72 users → 1 code with SF16 lost

• One CE per 10 users → 8 CE for 72 users

• But in reality only few users get F-DPCH due to limitation Ec/Io ≥ -6 dB !


RU20• Non configurable BLER target, independent on the CQI

• 10% for static channel

• 25% for fading channel

RU30• BLER target configurable, in dependence on

• fading

• CQI

• With stricter BLER target under good conditions up to 8 % more throughput can be achieved

Dynamic BLER Target - Idea


• BLER target settings can be done in dependence on the CQI• Low range reported CQI < medCQIRangeStart

• Intermediate rangemedCQIRangeStart ≤ Reported CQI < highCQIRangeStart

• High range highCQIRangeStart ≤ Reported CQI

• The CQI ranges are defined by NodeB commissioning parameters

medCQIRangeStartDefault = 12

highCQIRangeStartDefault = 25

Low CQI Intermediate CQI High CQI

Dynamic BLER Target - CQI Scenarios


• BLER target settings can be done in dependence on fading

• The amount of fading is expressed by the variance of the CQI• Static channel Variance < 1

• Weak fading 1 < Variance < 1.5

• Intermediate fading 1.5 < Variance < 2.5

• Strong fading Variance > 2.5

• The fading scenarios are non configurable

• BLER targets can be set for the most extreme fading scenarios only• Static channel

• Strong fading

• For the other fading scenarios the BLER targets still are non configurable• Weak fading BLER target = 6%

• Intermediate fading BLER target = 10%

Static

BLER target configurable

Default = 2-6 %

Weak fading

BLER target

= 6%

Intermediate fading

BLER target

= 10%

Strong fading

BLER target configurable

Default = 25%

Dynamic BLER Target - Fading Scenarios


• BLER targets for different CQI and fading scenarios configured with further Node B commissioning parameters

• Each parameter can have four values only• 2%

• 6%

• 10%

• 25%

• With RU20 10% under best fading conditions

• With RU30 2% under best fading and intermediate / good CQI conditions

• 10% - 2% = 8% gain for throughput achievable

Variance of Reported CQI

Low CQI Range Medium CQI Range High CQI Range

0 to 1 6% 2% 2%

1 to 1.5 6% 6% 6%

1.5 to 2.5 10% 10% 10%

>2.5 25% 25% 25%

Dynamic BLER Target - Default Settings

Non configurable


72 users

72 users72 users

72 HSPA Users per Cell - IdeaHSPA cells have high capacity of several Mbit/s

But for RT services often low data rate per user• AMR voice 4.75 - 12.2 Kbit/s

• Streaming e.g. 64 Kbit/s

Many users can have HSPA session simultaneously

Feature available since RU20


36 users

12 users24 users

72 HSPA Users per Cell - LimitationsRole of scheduler• 72 HSPA users per cell requires

• Either RU20 dedicated scheduler (full baseband)

• Or RU30 scheduler

• Otherwise 72 HSPA users per shared scheduler only

Logical and physical connection• 72 HSPA users referred to logical connection (MAC-d flow)

• Number of users served with packets simultaneously restricted by MaxNbrOfHSSCCHCodes (≤ 4)

Shared scheduler with 72 users


72 HSPA Users per Cell - HS-SCCH72 HSPA cells per user usually combined with code multiplexing

Up to 4 HS-SCCH running simultaneously• Some 0.01 to 0.1 W needed per HS-SCCH in dependence on CQI

→ total loss of power about 0.1 to 1 W (0.5 to 5 % of capacity of 20 W cell)

• Code with SF128 needed per HS-SCCH

→ maximum of 14 codes for HSDPA

SF 16

SF 32

SF 64

SF 128

SF 256

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

HS-SCCH2

HS-SCCH3

HS-SCCH4

SF16,0 SF16,1


72 HSPA Users per Cell - E-RGCH and E-HICHFor each HSUPA user individual E-RGCH and E-HICH signature needed

One channelization code can be shared by 40 signatures, i.e. 20 users

With 72 users 4 codes running simultaneously• By default 22 dBm = 0.158 W needed per E-RGCH and E-HICH

→ with 4 codes 0.634 W needed for E-RGCH and E-HICH

→ altogether 1.268 W needed (6.3 % of capacity of 20 W cell)

• Code of SF128 needed for E-RGCH/E-HICH

→ still fits into second tree above SF16

SF 16

SF 32

SF 64

SF 128

SF 256

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

HS-SCCH2

HS-SCCH3

HS-SCCH4

SF16,0 SF16,1

E-RGCH / E-HICH2 E-RGCH /

E-HICH3E-RGCH / E-HICH4


R99 Features

HSDPA

HSUPA

2ms TTI

5.8 Mbit/s

HSDPA+

HSUPA+



2ms TTI - IdeaSince RU20 HSUPA data channel E-DPDCH can operate on two time scales

10 ms TTI• Re-transmission after 40 ms

• Peak data rate of 3.84 Mbit/s supported

2 ms TTI• Re-transmission after 16 ms (i.e. less re-transmission delay)

• Peak data rate of 5.76 Mbit/s supported (i.e. higher peak data rate)

NodeB

associatedDCHAssociated DCH

E-DPCCHE-DPCCH

E-DPDCHE-DPDCH

2 or 10 ms TTI

E-HICHE-HICH

E-RGCHE-RGCH

E-AGCH

UE


2ms TTI - UE Classes

E- DCHCategory

max. E-DCHCodes

min. SF

2 & 10 ms TTI E-DCH

support

max. #. of E-DCH Bits* /

10 ms TTI

max. # of E-DCH Bits* /

2 ms TTI

Modu- lation

Referencecombination

Class

1 1 4 10 ms only 7296 - QPSK 0.73 Mbps

2 2 4 10 & 2 ms 14592 2919 QPSK 1.46 Mbps

3 2 4 10 ms only 14592 - QPSK 1.46 Mbps

4 2 2 10 & 2 ms 20000 5772 QPSK 2.92 Mbps

5 2 2 10 ms only 20000 - QPSK 2.0 Mbps

6 4 2 10 & 2 ms 20000 11484 QPSK 5.76 Mbps

7 4 2 10 & 2 ms 20000 22996 QPSK & 16QAM

11.5 Mbps


E-DPDCH packet → 2 or 10 ms time scale

Layer 1 signaling information → always 2 ms time scale

10 ms TTI• Signaling content can be repeated 5 time per E-DPCH packet

• Reliable signaling even at cell edge

2 ms TTI• Signaling content can be transmitted just once per E-DPCH packet

• Reliable signaling at cell centre only

2ms TTI - Limitations

1

1 1 1 1 1

E-DPDCH packet

Signaling information

1 2 3 4 5

E-DPDCH packets

Signaling information


UE coming from Cell_DCH state• Check of coverage

• Path loss must remain below CPICHRSCPThreEDCH2MS (Default 136 dB)

• Check includes following corrections• Cable loss (if MHA used)

• UE power class P_MAX (if lower than maximum allowed UE power in cell UETxPowerMaxRef)

• With PtxPrimaryCPICH = 33 dBm, CableLoss = 3 dB and UE of high power class

RSCP = -106 dBm needed by default


PtxPrimaryCPICH - CableLoss - measured CPICH RSCP < CPICHRSCPThreEDCH2MS + MAX(0, UETxPowerMaxRef – P_MAX)

BTS

UE2 ms TTIUE from Cell_DCH

10 ms TTI


UE coming from Cell_FACH state• Check of quality

• CPICH Ec/Io must be better than CPICHECNOThreEDCH2MS (Default -6 dB)

• In practise stricter limitation than for user coming from Cell_DCH


BTS

UE

2 ms TTIUE from Cell_DCH

10 ms TTI2 ms TTIUE from Cell_FACH


2ms TTI - ExampleSimulation performed by Qualcomm based on 3GPP TR 25.896 specifications

Network assumptions• Network with hexagonal cells of inter-site distance of 1000 m

• Users uniformly distributed

Receiver assumptions• Rake receiver and 2Rx diversity at Node B

• Rake receiver or equalizer at UE, without or with 2Rx diversity

Voice transmission assumptions• 12.2 Kbit/s

• VoIP with robust header compression

• DTX cycle of 8 TTIs for TTI = 2 ms and of 2 TTIs for TTI = 10 ms


2ms TTI - ExampleCapacity results (UE per cell)

95 UE 103 UE

10 ms TTI 2 ms TTI

106 UE

136 UE

10 ms TTI 2 ms TTI

No DTX

(CPC not used)

DTX

(CPC used)

Without CPC about 10% gain with 2ms TTI due to lower re-transmission delay

With CPC about 30% gain with 2ms TTI mainly due to DTX


5.8 Mbit/s - MechanismWith 2ms TTI maximum HSUPA configuration available• 2 codes SF2 + 2 codes SF4

• 1 code SF2 + 1 code SF4 on each branch of QPSK modulator

According 3GPP than no DPDCH

Thus SRB mapped onto E-DPDCH

SF2 SF4 SF8

Cch,2,0

Cch,2,1

Cch,4,0

Cch,4,1

Cch,4,2

Cch,4,3

E-DPDCH(on I- and Q-branch

2SF2 + 2SF4)


5.8 Mbit/s - Load per UserConsider load factor for 5.8 Mbit/s user under different conditions• Macro cell i = 0.6

• Micro cell i = 0.2

• Pico cell i = 0

User profile• R = 5.76 Mbit/s

• Eb/No about 1.3 dB according NSN EXCEL network planning sheet

• Activity factor = 1

Results• Macro cell L = 1.07 > 1 → service not available

• Micro cell L = 0.80 close to 1 → service just available

• Pico cell L = 0.67 < 1 → service clearly available

jjb

jj

NE

RWi

DPDCHEL

1

/

/1

1)(

0


R99 Features

HSDPA

HSUPA

HSDPA+

Flexible RLC

64QAM and MIMO

Dual cell HSDPA

HS Cell_FACH

CS voice over HSPA

Continuous packet connectivity

HSUPA+



Prior to RU20 one IP packet segmented into many small RLC packets of fixed size

Two options configurable by operator• 336 bit RLC PDU (16 bit header + 320 bit user data)

• 656 bit RLC PDU (16 bit header + 640 bit user data)

Than several RLC packets concatenated into one HSDPA packet

Number of concatenated RLC packets depends on CQI

Loss of capacity by following overheads• RLC header

• Granularity

Example• Actual CQI = 8

• Corresponds to HSDPA packet of 792 bit

• Can be filled with 2 RLC PDUs of 336 bit = 672 bit

• Remaining 792 - 672 = 120 bit remain unused

RLC - Static Handling

Segmentation

RNC

Node B

Concatenation / Padding

MAC-hs Header

Good air interface

Bad air interface

Padding


With RU20 size of RLC PDU adapted to size of IP packet

Than in dependence on CQI• If low → one IP packet segmented into several HSDPA

packets

• If high → several IP packets concatenated into one HSDPA packet

Much less loss of capacity• Just one RLC header per IP packet

• Much less padding, as most HSDPA packets filled up to the end with IP content

RLC - Flexible Handling

RNC

Segmentation / Concatenation

Node B

Maximum 1500 byte

Padding

MAC-hs Header

Example for segmentation of IP packet



Example for concatenation of IP packets

RNC

Segmentation / Concatenation

Node B

Maximum 1500 byte

PaddingMAC-hs Header

Maximum 1500 byte

Maximum 1500 byteMaximum 1500 byte


0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500

Rel. 6 with RLC PDU Size of 336 bits

Rel. 6 with RLC PDU Size of 656 bits

Rel. 7 Flexible RLC

overhead

HSDPA packet size in byte


RLC overhead almost negligible with big HSDPA packet size (high CQI)Very high gain especially for small HSDPA packet size (low CQI) due to much less padding


QPSK 2 bits/symbol

16QAM 4 bits/symbol

64QAM 6 bits/symbol

R5/R6 HSDPA modulation

• QPSK and 16QAM

R7 HSDPA modulation

• QPSK, 16QAM and 64QAM

64QAM - Principles


ModulationModulation

QPSKQPSK

Coding rateCoding rate

1/41/4

2/42/4

3/43/4

15 codes15 codes

1.8 Mbps1.8 Mbps

3.6 Mbps3.6 Mbps

5.4 Mbps5.4 Mbps

16QAM16QAM

2/42/4

3/43/4

4/44/4

7.2 Mbps7.2 Mbps

10.8 Mbps10.8 Mbps

14.4 Mbps14.4 Mbps

64QAM64QAM

3/43/4

5/65/6

4/44/4

16.2 Mbps16.2 Mbps

18.0 Mbps18.0 Mbps

21.6 Mbps21.6 Mbps

HS- DSCH

category

max. HS-DSCH Codes

min. * Inter-TTI interval

ModulationMIMO

supportPeakRate

13 15 1 QPSK/16QAM/ 64QAM

No 17.4 Mbps

14 15 1 QPSK/16QAM/ 64QAM

No 21.1 Mbps

17 15 1 QPSK/16QAM/ 64QAM or Dual-Stream MIMO

17.4 or 23.4 Mbps


21.1 or 28 Mbps

• HSDPA peak rate up to 21.1 Mbps

• UE categories 13,14,17 and 18 supported

• Available since RU20

64QAM - Principles


• Good channel conditions required to apply / take benefit of 64QAM CQI 26 !

• 64QAM requires 10 dB higher SINR than 16QAM

• Average CQI typically 20 in the commercial networks

21 Mbps0 Mbps 10 Mbps 14 Mbps

no gain from 64QAMsome gain from 64QAM

only available with 64QAM

64QAMQPSK 16QAM

1/4 2/42/4

1/6 2/4 3/4 3/43/4 5/6 4/4

CQI > 15 CQI > 25

64QAM - CQI Requirements


1 136 1 QPSK 0

2 176 1 QPSK 0

3 232 1 QPSK 0

4 320 1 QPSK 0

5 376 1 QPSK 0

6 464 1 QPSK 0

7 648 2 QPSK 0

8 792 2 QPSK 0

9 928 2 QPSK 0

10 1264 3 QPSK 0

11 1488 3 QPSK 0

12 1744 3 QPSK 0

13 2288 4 QPSK 0

14 2592 4 QPSK 0

15 3328 5 QPSK 0

CQI TB Size # codes Modulation Power Offset


Example

UE of category 13

3GPP 25.214 Annex Table 7F


16 3576 5 16-QAM 0

17 4200 5 16-QAM 0

18 4672 5 16-QAM 0

19 5296 5 16-QAM 0

20 5896 5 16-QAM 0

21 6568 5 16-QAM 0

22 7184 5 16-QAM 0

23 9736 7 16-QAM 0

24 11432 8 16-QAM 0

25 14424 10 16-QAM 0

26 15776 10 64-QAM 0

27 21768 12 64-QAM 0

28 26504 13 64-QAM 0

29 32264 14 64-QAM 0

30 32264 14 64-QAM -2


CQI TB Size # codes Modulation Power Offset

Example

UE of category 13

3GPP 25.214 Annex Table 7F


-10 0 10 20 30 40 500

2

4

6

8

10

12

14

16

18

20UE Cat.14 (64QAM) Throughput, Flex. RLC, Flat030 channel

Average HSDPA SINR / dB

Thro

ughput

/ M

bps

UE Cat. 10 (ref.)

UE Cat. 14

64QAM benefits starts at 10 Mbps

UE category 10

UE category 14

Min SINR of 28 dB required for 64QAM

64QAM - Throughput


64QAM - Usage

64QAM usageIn macro cell negligibleIn micro cell significantUsage improved, if UE supports Rx diversity


Tm

T2

T1

Rn

R2

R1

•••

•••

Input

Input 1

Input 2

Input m M x NMIMO system

OutputMIMOProcessor

• M transmit antennas and N receive antennas form MxN MIMO system

• Huge data stream (input) distributed towards M spatial distributed antennas (M parallel input bit streams 1..M)

• Spatial multiplexing generate parallel “virtual data pipes”

• MIMO uses multi-path effects instead of mitigating them

MIMO - Principles


HS- DSCH

category

max. HS-DSCH Codes

min. * Inter-TTI interval

ModulationMIMO

supportPeakRate

15 15 1 QPSK/16QAM Yes 23.4 Mbps

16 15 1 QPSK/16QAM Yes 28 Mbps


17.4 or 23.4 Mbps


21.1 or 28 MbpsD

ata

stre

am 1

UE: 2 Rx

antennas

WBTS: 2 Tx

antennas

Dat

a st

ream

2

• RU20 (3GPP R7) introduces 2x2 MIMO with 2 Tx / 2 Rx

• Double transmit on BTS side, 2 receive antennas on UE side

• System can operate in dual stream (MIMO) or single (SISO, non-MIMO) mode

• MIMO 2x2 enables 28 Mbps peak data rate in HSDPA

• 28 Mbps peak rate in combination with 16QAM

• No simultaneous support of 64QAM and MIMO with RU20, but with RU30

• Not possible to enable MIMO and DC-HSDPA in parallel with RU20, but with RU30

• UE categories for MIMO support are 15, 16, 17 and 18

MIMO - Principles


• When using Spatial Diversity (single stream) only primary TB is sent

• Weights w1 and w2 applicable

• When using Spatial Multiplexing (dual stream) primary and secondary TB are sent

• Weights w1, w2, w3 and w4 applicable

• Contributions from both transport blocks sent via both antennas

MIMO - NSN Implementation


• With MIMO two CPICH are required• 2nd CPICH orthogonal to first one

• 2nd CPICH has to operate with same power as first one

• UE measures CQI for each CPICH individually• Both values reported via single HS-DPCCH

• MIMO offered only, if CQI difference does not exceed mimoDeltaCQIThreshold (hardcoded to 2)

• UE consideres sum of both CPICH at both Rx antennas• Should be zero due to orthogonality

• But in reality at each Rx antenna non zero amplitude and phase due to multi-path

• Preferred weights• w1, w3 and w4 fixed

• Only w2 has to be estimated by UE on basis of downgraded orthogonality

• w2 reported via HS-DPCCH

MIMO - NSN Implementation


MIMO - Throughput

Source

Christian Mehlführer, Sebastian Caban and Markus Rupp

MIMO HSDPA Throughput Measurement Results in an Urban Scenario

In: Proceedings of the IEEE, Anchorage, USA, September 2009

2Tx 2Rx 2Tx+ 2Rx

2x2 MIMO

2x2 MIMO+2Tx

2x2 MIMO +2Rx

4x4 MIMO

Urban cell with radius = 400 mHSDPA power = 30 dBmHardly any gain with 2TxBut about 100% gain with 2x2 MIMO


Peak throughput• MIMO alone with 16QAM → 2 * 14 Mbps = 28 Mbps• 64QAM alone without MIMO → 6 / 4 * 14 Mbps = 21 Mbps• MIMO with 64QAM → 2 * 21 Mbps = 42 Mpbs

UE categories• MIMO alone → Category 15 + 16• 64QAM alone → Category 13 + 14• 64 QAM OR MIMO → Category 17 + 18• 64 QAM AND MIMO → Category 19 + 20

HS- DSCHcategory

max. HS-DSCH Codes

ModulationMIMO

supportPeakRate

19 15 QPSK/16QAM/ 64QAM

Yes 35.3 Mbps

20 15 QPSK/16QAM/ 64QAM

Yes 42.2 Mbps

64QAM AND MIMO - Principles


Selection of MIMO mode and modulation• Both the MIMO mode and the modulation are offered in dependence on the air

interface• Bad conditions → Single stream• Good conditions → Dual stream• Excellent conditions → Dual stream + 64QAM

• If both MIMO AND 64QAM is not possible, but either MIMO OR 64QAM, then MIMO is preferred

Dual stream + 64QAM

Dual stream

Single stream

64QAM AND MIMO - Feature Selection


MIMO + 64QAM requires

Very high SINR > 25 dB

Uncorrelated multi-path

components

From Landre et al., realistic performance

of HSDPA MIMO in macro cell

environment, Orange 2009

64QAM AND MIMO - Throughput


5 MHz 5 MHz

F1 F2

MIMO (28 Mbps) or 64QAM (21 Mbps)

10 MHz

DC-HSDPA and 64QAM (42 Mbps)

2 UE, each using 5 MHz RF Channel

Peak Connection Throughput = 28 Mbps

1 UE, using 2 × 5 MHz RF Channels

Peak Connection Throughput = 42 Mbps

F1 F2

Dual Cell ApproachBasic Approach

• Prior to 3GPP R8 HSDPA channel bandwidth limited to 5 MHz

• 3GPP R8 allows 2 adjacent channels to be combined effective HSDPA channel bandwidth of 10 MHz

• 3GPP R8 dual cell HSDPA (RU20) can be combined with 64QAM but not with MIMO 42 Mbps HSDPA peak rate

• 3GPP R9 (RU30) allows combination with both 64QAM and MIMO

Dual Cell HSDPA - Principles


F1 F2F1 F2 F1 F2

UE on top of ranking list on both RF carriers

UE on top of ranking list on RF carrier 1

UE on top of ranking list on RF carrier 2

UEx UExUE1UE1 UE1

• Dual cell HSDPA provides greater flexibility to HSDPA Scheduler (can allocated resources in the frequency domain as well as in the code and time domains)

• UE categories for dual cell HSDPA support are 21, 22, 23 and 24

HS- DSCH

category

max. HS-DSCH Codes

ModulationMIMO

supportPeakRate

21 15 QPSK/16QAM No 23.4 Mbps

22 15 QPSK/16QAM No 28 Mbps

23 15 QPSK/16QAM/64QAM No 35.3

Mbps

24 15 QPSK/16QAM/64QAM No 42.2

Mbps

Dual Cell HSDPA - Principles


• Cells paired for dual cell HSDPA must obey the following rules• Belong to same sector

• Have same Tcell value

• Thus belong to same logical cell group

• Dual cell HSDPA cells belonging to different sectors must fulfil the following rules• Belong to different logical cell groups

• Thus have different Tcell valueSectorID = 1

Tcell = 0

RF Carrier 2

SectorID = 2

Tcell = 3

SectorID = 3

Tcell = 6

SectorID = 1

Tcell = 0 SectorID = 2

Tcell = 3

SectorID = 3

Tcell = 6

RF Carrier 1

Dual Cell HSDPA - Sector Configuration


• Serving cell (primary carrier) provides full set of physical channels• Inner loop power control driven by serving cell by F-DPCH

• HARQ ACK/NACK and CQI for both carriers reported to serving cell

• Uplink data sent to serving cell

• Secondary carrier provides only HS-SCCH and HS-PDSCH

• The return channel must be HSUPA

HS-SCCH

HS-SCCHHS-PDSCH

HS-PDSCHHS-DPCCHDPCCH

F-DPCH

E-DPDCHE-DPCCH

Downlink Channels

Uplink Channels

Primary RF CarrierServing cell

Secondary RF Carrier

Dual Cell HSDPA - Physical Channel Configuration


• Scheduling metric calculated for each RF carrier individually

• Same schedulers available as for single carrier HSDPA

• Instantaneous Transport Block Size TBS generated for each carrier individually by link adaptation

• Average TBS based upon previously allocated TBS in both cells belonging to the DC-HSDPA cell pair, i.e. the total average throughput allocated to the UE

• An UE which is scheduled high throughput in cell 1 will have a reduced scheduling metric for being allocated resources in cell 2

• UE served by both carriers at the same time, if it has highest scheduling metric for both simultaneously

Cell2Cell1

Cell1Cell1 TBS Average

TBS Metric

Cell2Cell1

Cell2Cell2 TBS Average

TBS Metric

Shared Scheduler per DC-HSDPA cell pair

DC-HSDPA UE

Dual Cell HSDPA - Packet Scheduling


Peak throughput• Dual cell HSDPA alone → 2 * 14 Mbps = 28 Mbps• Dual cell HSDPA with 64QAM → 6 / 4 * 28 Mbps = 42 Mbps• Dual cell HSDPA with MIMO → 2 * 28 Mbps = 56 Mbps• Dual cell HSDPA with 64QAM + MIMO → 2 * 42 Mbps = 84 Mbps

UE categories• Dual cell HSDPA alone → Category 21 + 22• Dual cell HSDPA with 64QAM alone → Category 23 + 24• Dual cell HSDPA with MIMO → Category 25 + 26• Dual cell HSDPA with 64 QAM + MIMO → Category 27 + 28

Dual Cell HSDPA - Combination with MIMO


HS- DSCHcategory

max. HS-DSCH Codes

ModulationMIMO

support

DC-HSDPA support

PeakRate

19 15 QPSK/16QAM/ 64QAM Yes No 35.3 Mbps

20 15 QPSK/16QAM/ 64QAM Yes No 42.2 Mbps

21 15 QPSK/16QAM No Yes 23.4 Mbps

22 15 QPSK/16QAM No Yes 28 Mbps

23 15 QPSK/16QAM/ 64QAM No Yes 35.3 Mbps

24 15 QPSK/16QAM/ 64QAM No Yes 42.2 Mbps

25 15 QPSK/16QAM Yes Yes 46.7 Mbps

26 15 QPSK/16QAM Yes Yes 56 Mbps

27 15 QPSK/16QAM/ 64QAM Yes Yes 70.6 Mbps

28 15 QPSK/16QAM/ 64QAM Yes Yes 84.4 Mbps

Single cell

Dual cell

Dual Cell HSDPA - Combination with MIMO


HS-DPCCH

Other common channels like

E-AGCH, E-RGCH, F-DPCH

Other common channels like

E-AGCH, E-RGCH, F-DPCH UE

BTS

HS-SCCH

HS-SCCH

HS-DSCH

TBS3

TBS4HS-DSCH

TBS1

TBS2

Primary Cell

Secondary Cell

Dual Cell HSDPA - Combination with MIMO• With RU30 dual cell HSDPA can be combined with MIMO for NRT services

• 4 HSDPA packets can be transmitted simultaneously to one UE

• ACK/NACK for all of them transmitted to serving cell via single HS-DPCCH


Huge impact on cell coverage as compared to normal HSDPA mode (r = 1)

Small Overhead on HS-DPCCH

S-CPICH needed for MIMO

Dual Cell HSDPA - Throughput

About 100% gain of throughput with dual cell HSDPAAbout 50% additional gain of throughput with MIMO


RU20• Very low capacity available in Cell_FACH state only

• 32 kbps on DL (FACH, S-CCPCH)• 16 kbps on UL (RACH, PRACH)

• Causes problems in case of applications requiring frequent transmission of small amount of data

• High signaling load due to frequent state transitions• High battery power consumption for UE• Strong occupation of dedicated resources for low total throughput

RU30• HSDPA available in Cell_FACH state, thus much higher capacity of 1.8 Mbps on DL• UEs downloading small amount of data need not to enter Cell_DCH any more• HSUPA in Cell_FACH NOT available yet

HS Cell_FACH - Principles


• All logical channels up to now mapped onto FACH now can be mapped onto HS-DSCH

• Even broadcast and paging information can be transmitted via HS-DSCH (to UEs in Cell_PCH or URA_PCH)

HS Cell_FACH - Channel Mapping


HS Cell_FACH on DL, but not on UL• Low UL performance (RACH used)

• No ACK/NACK and CQI sending• Blind repetition for HARQ • “Default CQI” value for link adaptation

• Mobility based on cell reselection as usual in Cell_FACH

DL: HS-D

SCH

UL: RACHHS-DPSCH

Example:4 retransmissions

Original transmissions

HS Cell_FACH - Air Interface Transmission


• Like for R99• One can select for which RRC establishment cause HS Cell_FACH or HS Cell_DCH is

preferred• Transition Cell_FACH to Cell_DCH triggered by high activity, i.e. huge amount of data in DL

RLC buffer

• In contradiction to R99• Cell_FACH can be offered, until no resource available in this state any more• Thresholds FachLoadThresholdCCH and PtxThresholdCCH are ignored

HS Cell_FACH - Channel Type Selection


[REF. WCDMA for UMTS – HSPA Evolution and LTE, HH AT]

Assumed IP Header Compression

• Two different voice transmission scenarios are being considered with HSPA

• VoIP

• UE connects with network as for standard packed data transmission

• Connection is established by using “web communicators”

• Hard to establish appropriate charging schemes

• CS voice over HSPA

• AMR voice frames being carried by HSPA transport channels transparent for the user

CS Voice over HSPA - Principles


HS-DSCH

E-DCH

for voice, SRB and other services

• SRB must be mapped to HSPA

• Supported RAB combinations:

• Speech CS RAB

• Speech CS RAB + PS streaming RAB

• Speech CS RAB + 1...3 PS interactive / background RABs

• Speech CS RAB + PS Streaming RAB + 1...3 PS interactive / background RABs

• Codecs supported for CS voice over HSPA

• AMR FR set (12.2, 7.95, 5.9, 4.75), AMR HR set (5.9, 4.75), AMR with 12.2 alone

• AMR-WB set (12.65, 8.85, 6.6)

• Load based AMR selection algorithm not used while CS Voice is mapped on HSPA

• Priority class of CS voice over HSPA = 14

• Lower than SRB (15)

• Higher than streaming 13)

CS Voice over HSPA - Principles


PtxTargetTotMin (40 dBm)

CS Voice over HSPA - DL Admission Control

Common channels

DCH voice + SRB

DCH streaming

DCH NRT

HSDPA voice + SRB

HSDPA streaming

HSDPA NRT

PtxCellMax (43 dBm)

PtxTargetTotMax (41 dBm)

PtxTarget (40 dBm)

PtxNCDCH

PtxNCHSDPA

Power

New load target for total non controllable traffic PtxTargetTot• Adjusted in dependence on DCH non controllable traffic PtxNCDCH

• Adjusted within configurable limits PtxTargetTotMin and PtxTargetTotMax

Limitations• Lower threshold PtxTargetTotMin ≥ PtxTarget

• Upper threshold PtxTargetTotMax ≤ PtxCellMax

Available capacity for total NCT

Available capacity for DCH NCT


CS Voice over HSPA - DL Admission ControlPtxTargetTot depends on• Actual DCH non controllable traffic PtxNCDCH (e.g. 38/39dBm = 6.3/7.9 W)

• Setting of maximum allowed target PtxTargetTotMax (e.g. 41 dBm = 12.6 W)

• Setting of classical DCH load target PtxTarget (e.g. 40 dBm = 10 W)

Example• PtxNCDCH = 6.3 W → PtxTargetTot = 12.6 W – 6.3 W (12.6 W / 10 W – 1) = 11.0 W = 40.4 dBm

• PtxNCDCH = 7.9 W → PtxTargetTot = 12.6 W – 7.9 W (12.6 W / 10 W – 1) = 10.5 W = 40.2 dBm

Conclusions• The higher the DCH non controllable traffic, the lower PtxTargetTot

• PtxNCDCH = PtxTarget → PtxTargetTot = PtxTarget

no capacity for CS voice over HSPA at all

• PtxNCDCH = 0 → PtxTargetTot = PtxTargetTotMax

maximum capacity for CS voice over HSPA

PtxTargetTot = PtxTargetTotMax - PtxNCDCH

PtxTargetTotMax

PtxTarget-1( )


PtxNCDCH + PtxNCHSDPA + Pnew < PtxTargetTot

PtxNCHSDPA + Pnew < PtxMaxHSDPA

Pnew = (GBR × Activity Factor) ×Existing HSDPA Power

Existing Throughput

CS Voice over HSPA - DL Admission ControlTo admit CS voice over HSPA, the following conditions must be fulfilled

Like for DCH voice, RT over NRT can be applied in case of lack of resources

The power Pnew needed for the new user is estimated as follows

Activity factor• Initial value set by parameter RRMULDCHActivityFactorCSAMR (Default 50 %)

• Than measured on running connection

Example• GBR = 12.2 Kbit/s, activity factor = 0.5, HSDPA power = 6 W, throughput = 1 Mbit/s

• Pnew = 12.2 Kbit/s * 0.5 * (6 W / 1000 Kbit/s) = 0.037 W = 16 dBm


CS Voice over HSPA - UL Admission Control

DCH voice + SRB

DCH streaming

DCH NRT

HSUPA voice + SRB

HSUPA streaming

HSUPA NRT

PrxMaxTargetBTS (e.g. 6 dB)

PtxTargetMax (e.g. 4 dB)

PrxTarget (e.g. 3 dB)

PrxNCDCH

PrxNCHSUPA

RTWP

Analogue to DL new load target for total non controllable traffic PtxTargetAMR• Adjusted in dependence on DCH non controllable traffic PrxNCDCH

• Adjusted within configurable limits PtxTarget and PtxTargetMax

Limitations• Lower threshold given by classical DCH load target PrxTarget

• Upper threshold PtxTargetMax ≤ PtxMaxTargetBTS

Available capacity for total NCT

Available capacity for DCH NCT

PrxNoise (e.g. -106 dBm)


CS Voice over HSPA - UL Admission ControlAccording NSN documentation for PtxTargetAMR complex dependency on• Power situation

• Throughput situation

Rearrangement of original NSN formulas gives, however, relationship analogue to DL

• Actual DCH non controllable traffic PrxNCDCH (e.g. 1/2 dB = 1.26/1.58)

• Setting of maximum allowed target PrxTargetMax (e.g. 4 dB = 2.51)

• Setting of classical DCH load target PrxTarget (e.g. 3 dB = 2.00)

Example• PrxNCDCH = 1 dB = 1.26 → PtxTargetAMR = 2.51 – 1.26 (2.51 / 2.00 – 1) = 2.19 = 3.4 dB

• PrxNCDCH = 2 dB = 1.58 → PtxTargetAMR = 2.51 – 1.58 (2.51 / 2.00 – 1) = 2.11 = 3.2 dB

Same conclusions as for DL

PrxTargetAMR = PrxTargetMax - PrxNCDCH

PrxTargetMax

PrxTarget-1( )


Load factor () [0..1]

Noise Rise [dB]

Noise floor e.g. -106 dBm

PrxTarget -103 dBm

PrxTargetMax -102 dBmPrxTargetMax e.g. 4 dB

PrxNCDCH e.g. 2 dBPrxNCDCH -104 dBm

PrxTargetAMR -102.8 dBm

PrxTarget e.g. 3 dB

CS Voice over HSPA - UL Admission Control

PrxTargetAMR 3.2 dB


CPC “Sub-features”:

• UL DPCCH Gating (UL DTX)

• CQI Reporting reduction

• Discontinuous UL Reception (MAC DTX)

• Discontinuous DL Reception (DL DRX)

• Discontinuous UL DPCCH transmission and reception during UE UL traffic inactivity (UL DPCCH gating + DRX at BTS)

• CQI reporting reduction (switched from periodical to synchronized with DPCCH burst)

• Stopping E-DPCCH detection at NodeB during DPCCH inactivity

• Discontinuous DL Reception (DRX at UE)

• Stop receiving HS-SCCH, E-AGCH and E-RGCH when not needed

• Faster response times

• Increased number of low activity packet users in CELL_DCH state

• Motivation and Benefits

• Increased capacity for low data rate applications

• Longer battery life

Continuous Packet Connectivity - Principles


• CPC eliminates the requirement for continuous transmission and reception during periods when data is not transferred

• Exploits discontinuities in packet data services

• Designed to work with VoIP

UE Power Saving Inactive HSPA UE require less resource

Increased talk time

USER GAIN SYSTEM GAIN

Reduced delay for re-starting data transfer

Increased Capacity

Potential to keep more inactive UE

in CELL_DCH

Uplink DTX

Downlink DRX

Reduced CQI Reporting

Uplink DRX

Continuous Packet Connectivity - Principles

HS-SCCH Less Operation

New Uplink DPCCH Slot Format


DPDCH

DPCCH

E-DPDCH

DPCCH

E-DPDCH

DPCCH

R99 service Voice (20ms)

R6 Voice 2ms (R6 VoIP)

R7 Voice 2ms (R7 VoIP) UL DPCCH Gating

• UL Gating (UL DTX) reduces UL control channel (DPCCH) overhead

• If no data to sent on E-DPDCH or HS-DPCCH UE switches off UL DPCCH

• DPCCH Gating precondition for other CPC sub-features

Continuous Packet Connectivity - UL Gating


E-DCH 2ms TTI example: CPCNRT2msTTI

10ms Radio Frame 10ms Radio Frame

2ms subframe

CFN

UE_DTX_Cycle_1

UE_DTX_Cycle_2

Inactivity Threshold for UE cycle 2

10ms Radio Frame

UE_DTX_Cycle_2

switch to UE cycle 2

cycle 1 cycle 2

E-DPDCH

Tx, 2ms TTI

DPCCH

pattern

DPCCH with

E-DCH, 2ms TTI

synch reference

CFN = Connection Frame Number

Used for any synchronized procedure in UTRAN

Pre/Postambles not shown here

no data on E-DPDCH

N2msUEDPCCHburst1

RNC; 1, 2, 5; 1 subframe

N2msUEDTXCycle1

RNC; 1, 4, 5, 8, 10, 16, 20; 8 subframes

N2msInacThrUEDTXCycl2

RNC; 1, 2, 4, 8, 16, 32, 64, 128, 256; 64 TTIs

N2msUEDPCCHburst2

RNC; 1, 2, 5; 1 subframe

N2msUEDTXCycle2

RNC; 4, 5, 8, 10, 16, 20, 32, 40,

64, 80, 128, 160; 16 subframes

Continuous Packet Connectivity - UL Gating


Reduced CQI reporting takes

place only if the CQI reporting

pattern defined by the last

HS-DSCH transmission and

CQI cycle overlaps the UL

DPCCH burst of the UE DTX

pattern

CQI Reporting Reduction reduces the CQI reporting when there are no data transmitted on HS-DSCH for a longer period of time

ACK/NACK transmission

CQI period 2ms

CQI period 4ms

CQI period 8ms

CQI transmission time defined by CQI period, but not overlapping with DPCCH transmissionno CQI transmission

CQI Transmission

DPCCH pattern

UE_DTX_cycle_1 UE_DTX_cycle_1

UE_DTX_cycle_2 UE_DTX_cycle_2

7.5slots

HS-DSCH reception CQI_DTX_TIMER

UE_DTX_cycle_2

CQI_DTX_Priority set to 1

CQI_DTX_Priority set to 0

N2msCQIFeedbackCPC

CQI feedback cycle (when CQI reporting not reduced)

RNC; 0, 2, 4, 8, 10, 20, 40, 80, 160 ; 10 ms

N2msCQIDTXTimer

RNC; 0, 1, 2, 4, 8, 16, 32, 64, 128,

256, 512, infinity; 64 subframes

Continuous Packet Connectivity - Reduced CQI Reporting


UE can transmit E-DPDCH data only at predefined time instances

N2msMACInacThr

RNC; infinity, 1, 2, 4, 8, 16, 32, 64, 128,

256, 512; infinity subframes

N2msMACDTXCycle

length of MAC DTX Cycle

RNC; infinity, 1, 4, 5, 8, 10, 16, 20; 8 subframes

DTX

Continuous Packet Connectivity - Discontinuous UL Reception


UE battery power consumption

Cell_DCH No CPC

Cell_DCH With CPC

Cell_FACH

Cell_PCH

optimization for RTT measurements OR

CPC currently not active for UE

No delayed transition, as with Cell_PCH lowest power consumption

optimization for battery power consumption AND

UE can power down in Cell_PCH

Moderate delay for transition

Cell_DCH with CPC better than Cell_FACH

But worse than Cell_PCH for power consumption

optimization for battery power consumption AND

UE can NOT power down in Cell_PCH

Strong delay for transition

Cell_DCH with CPC better than Cell_FACH

Continuous Packet Connectivity - Battery Power Optimization


R99 Features

HSDPA

HSUPA

HSDPA+

HSUPA+

Interference cancellation receiver

Frequency domain equalizer



RU20• Users with low level services (usually with 10ms TTI) strongly interfered by

users with high level services (usually with 2ms TTI)

RU30• Interference contribution of 2ms TTI users subtracted from total signal

arriving at BTS before demodulating and decoding the signals of 10ms TTI users

• Less power needed by 10ms TTI users due to cancelled interference of 2ms TTI users

• 2ms TTI users less interfered by 10ms TTI users due to lower power

• Optionally interference contribution of individual 2ms TTI users subtracted before demodulating and decoding other 2ms TTI users

Interference Cancellation - Principles


Types of users• IC users

• Users whose interference contribution is cancelled from the total signal• Users mapped on E-DCH with 2ms TTI (usually those with highest power)• Do not get any direct benefit from interference cancellation

• Non-IC users• Users for which interference is reduced, as the contribution of the non IC users is cancelled from the

total signal• Remaining users mapped on E-DCH with 2ms TTI (usually such ones with lower power)• All 10ms TTI E-DCH users• All DCH users

RTWP

Time

IC Users = interferers to be cancelled

Non IC Users = users for which interference is reduced

Interference Cancellation - Principles


Re-modulate2ms HSUPA

De-modulate2ms HSUPA

2ms HSUPAuser data

Total UL signal from

antenna

De-modulateother

10ms HSUPADCH

user data

2ms HSUPA

Interference cancelled

Non-IC users signal

(Residual signal)

“IC users”

“Non-IC users”

Parallel interference cancellation PIC• Total UL signal received with rake receiver or frequency domain equalizer• Turbo decoding to obtain (strongest) 2 ms TTI E-DCH signals • Decoded data used to reconstruct original 2 ms TTI signals (= interferers for other

users). Reconstruction includes turbo encoding, spreading and modulation• Cancel interference from (strongest) 2 ms TTI user: Reconstructed signals are

summed up and subtracted from the original total antenna signal non-IC users’ signal (residual signal)

• Individual non-IC user signals demodulated on the residual signal, benefiting from lower interference level improving cell coverage and capacity

Interference Cancellation - Basic Algorithm


Benefit• Part of received total wideband power is cancelled

• RTWP = PNoise + PR99 + P10ms + P2ms

• Residual RTWP = PNoise + PR99 + P10ms + (1-β) * P2ms

• Achievable interference reduction factor β highly dependent on• Quality of signal that should be cancelled• Data rate of UE to be cancelled• Radio channel of the UE (multi-path profile, velocity)

Noise

R99 users

HSUPA

10 ms

HSUPA 2 ms

Noise

R99 users

HSUPA

10 ms

HSUPA 2 ms

RTWP ResidualRTWP

Interference Cancellation - Basic Algorithm


Residual stream reconstruction RSR• Basic PIC

• IC users do not benefit directly from the reduced interference • Their signals are demodulated in parallel on the original antenna signal

• Enhanced PIC• Demodulate signals of IC users again after residual signal reconstruction for

these signals (to gain from basic interference cancellation)• Residual Stream Reconstruction RSR

• For each 2 ms TTI user, his individual signal is reconstructed• The reconstructed signal is added to the common residual signal• Interference introduced by 2 ms TTI users canceled from the signals of other 2 ms TTI users

Interference Cancellation - Enhanced Algorithm


Total UL signal fromantenna

De-modall others

2ms HSUPAinterference

cancelled

RSR De-mod2ms HS

10ms HSUPADCH

user data

“Non-IC users”

2ms HSUPAuser data

“IC users”

Common

residual signal

First stage detected IC users data

Individual residual signal after interference cancellation and residual stream reconstruction

Second stage detected IC users data

Re-modulate2ms HSUPA

De-modulate2ms HSUPA

Interference Cancellation - Enhanced Algorithm


PIC pool handling• IC can be enabled only, if a cell belongs to a PIC pool

• One pool supports up to 6 cells• 3 cells may perform IC simultaneously• One BTS supports up to 4 pools• Basic IC requires 48 channel elements per pool

• A cell is assigned to a specific PIC pool by the parameter AssignedPICPool

f1 f2

f1f1

f2 f2 Cells in PIC pool

Cells with IC

Interference Cancellation - PIC Pool


With 2x diversity• Up to 6 cells per PIC pool (6x2 antennas)• Up to 3 of them can perform IC simultaneously (3x2 antennas)

With 4x diversity• Up to 3 cells per PIC pool (3x4 antennas)• Only 1 of them can perform IC simultaneously (1x4 antennas)

f1 f1

f12 Rx 4 Rx

Interference Cancellation - PIC Pool


• The total traffic is checked against the following thresholds• Total RTWP before IC against PrxMaxOrigTargetBTS (Default 8 dB)• Residual RTWP after IC against PrxMaxTargetBTS (Default 6 dB)

• The R99 RT traffic is checked against• PrxTargetOrig before IC (Default 4 dB)• PrxTarget after IC (Default 4 dB)

RTWP

PrxNoise

PrxMaxOrigTargetBTS

PrxTargetOrig

PrxMaxTargetBTS

PrxTarget

R99 users

HSUPA

10 ms

HSUPA 2 ms

R99 users

HSUPA

10 ms

HSUPA 2 ms

Interference Cancellation - Modified Load Targets

With interference cancellation 2dB higher load target for total traffic8dB corresponding to 84% load instead of6dB corresponding to 75% load


Interference gain

Example2 Rx diversity10 users in HSUPA cell

With interference cancellation user experiences about ½ to 1 dB less noise rise effectively

From Sambhwani et al., UL interference

cancellation in HSPA, Qualcomm 2009

Interference Cancellation - Effective Noise Rise


Example2 Rx diversity10 users in HSUPA cell

With lower experienced noise rise about 2 times more throughput

From Sambhwani et al., UL interference

cancellation in HSPA, Qualcomm 2009

Interference Cancellation - Throughput


Handling of multi-path propagation• Identify time delays at which significant energy arrives and allocation of the

rake fingers to those peaks• Track fast changes of phase and amplitude originating from fast fading by

each rake finger• Combine demodulated and phase adjusted symbols across all active fingers

and present them to decoder for further processing

Rake Receiver - Principles


Problem• With HSUPA very short spreading codes (SF down to 2) introduced• Very sensitive to inter-symbol interference introduced by time delay• Maximum data rate of e.g. 5.8 Mbit/s not achieved, saturation at e.g. ≈ 4

Mbit/s even under very good signal-to-noise-ratio conditions

Rake Receiver - Problems


Idea• Reduce inter-symbol interference by combination of

• Linear equalization• Fast convolution

• Obtain peak data rates closer to the limits of• HSUPA 5.8 Mbit/s (2xSF2 + 2xSF4 with QPSK• HSUPA 11.5 Mbit/s (2xSF2 + 2xSF4 with 16QAM)

Frequency Domain Equalizer - Principles


• Frequency domain equalizer is a combination of linear equalization and fast convolution

• Linear equalization → current and the past values of received signal linearly weighted by equalizer coefficients and summed up to produce output

• Fast convolution → filtering of signal not done in time domain, but after FFT by multiplication in frequency domain (low pass filter)

• Reduces effects of inter-symbol-interference arising from user’s own signal due to multipath propagation

• Applied to users with granted 2xSF2 + 2xSF4 (QPSK or 16-QAM)

signal FFT

pilotChannel

estimation

IFFT Despreading and detection

bits

Time domain

Frequency domain

MMSE filter coefficient calculation



x(k) h(k)

Before filtering

After filtering

High frequencies removed by low pass



non-boosted mode

DPCCH DPCCH

E-DPCCH E-DPCCH

E-DPDCH

E-DPDCH

low E-TFC high E-TFC

• Frequency domain equalizer requires reliable decoding of E-DPCCH• In case of 2xSF2 + 2xSF4 E-DPCCH very strongly interfered by E-DPDCH• Boosted mode

• Power of E-DPCCH not related to power of DPCCH• But related to power of E-DPDCH

DPCCH DPCCH

E-DPCCH

E-DPCCHE-DPDCH

E-DPDCH

low E-TFC high E-TFC

boosted mode

E-DPCCH power proportional to E-DPDCH power

non-boosted mode

E-DPCCH power goes parallel to DPCCH power

Frequency Domain Equalizer - E-DPCCH Boosted Mode


Data rate vs average CIR @ 10% BLER after 1st Tx (Ped A 3)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

-20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0

CIR @ 10% BLER

Tp

[kb

its]

FDE 16QAM -boosted

FDE QPSK

RAKE QPSK

Throughput versus average CIR (10% BLER after first transmission) – pedestrian fading channel A3

FDE + 16QAM => 77,8% higher throughput achievable

FDE + QPSK => 22,2% higher throughput achievable

FDE enables achieving higher data rates for users

closer to the antenna

Frequency Domain Equalizer - Throughput

Date post:	30-Nov-2015
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06 RN31576EN30GLA0 Capacity Enhancement

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