NSN 3G Uplink Optimization

Nokia Siemens Networks – 3G Uplink OptimizationNSN response to Annex 6, Chapter 5 in T-Mobile Netherlands Single RAN RfQ

1 © Nokia Siemens Networks 2011 Customer Confidential

NSN response to Annex 6, Chapter 5 in T-Mobile Netherlands Single RAN RfQSeptember 2011

Introduction

TargetTarget

This presentation is intended to provide response to Annex 6 Chapter 5 in T-Mobile Netherlands Single RAN RfQ where the Supplier is requested to provide an overview of measures taken to reduce the radio and baseband/RNC resource allocation in a high smartphone penetration environment with extremely high signaling load.

ConfidentialityConfidentiality


All information related to the Nokia Siemens Networks 3G Uplink Optimization features, functionality’s and roadmaps presented in this document are strictly Nokia Siemens Networks Customer confidential.

No information shall be disclosed to any third party without permission from Nokia Siemens Networks.

Uplink vs Downlink Traffic in Live 3G Networks (1)

Europe 2

South America

Europe 1

0.25

0.20

0.15

HSUPA / HSDPA daily volume ratio at selected operators

MEA

Europe 3


Source: NSN Analysis, April 2011

0.10

0.05

0

01.03.2010 01.07.2010 01.01.201101.10.2010 01.04.2011

• Uplink traffic volume is 15-20% of downlink

• Uplink volume is growing faster than downlink (due to HSUPA)

Europe 3

Uplink vs Downlink Traffic in Example Live 3G Network

HSDPA vs HSUPA ratio 10x now and getting smaller due to higher HSUPA penetration

HSDPA vs HSUPA + WCDMA UL ratio 6x and

stabile


Uplink vs Downlink Capacity in Theory

1.06 1.11

1.311.44 1.52

1.74

0.65 0.650.79

0.8

1.0

1.2

1.4

1.6

1.8

2.0

bp

s/H

z/c

ell

Evolution of HSPA efficiency

Downlink

Uplink

• Downlink 1.31 bps/Hz/cell

• Uplink 0.33 bps/Hz/cell (0.53 with IC)

• => Theoretical ratio 4x


0.55

0.33 0.33 0.33

0.530.65 0.65

0.79

0.0

0.2

0.4

0.6

0.8

HS

PA

R6

HS

PA

R6

+ U

E

eq

ualiz

er

HS

PA

R7

64

QA

M

HS

PA

R8

DC

-H

SD

PA

HS

PA

R9

DC

-H

SD

PA

+M

IMO

HS

PA

R1

0 Q

C-

HS

DP

A+

MIM

O

LT

E R

8

bp

s/H

z/c

ell

Smartphones Increase Signalling Load

• Smartphones create frequent transmission of small packets which requires frequent RRC state

• More multi-RABs due to smartphones


which requires frequent RRC state changes (DCH allocations) and RACH signalling which increases uplink interference

Starting Point for Uplink Optimization

• In theory, the networks should be downlink limited because the traffic is 5-6x in downlink while the capacity is 4x.

• The higher uplink noise rise is mainly caused by the control overhead

– RACH preambles and messages, like RRC requests, uplink capacity request and user plane data, especially related to smartphone traffic

– DPCCH overhead. For example, with AMR5.9 kbps 64% of interference comes from DPCCH.

– DPCCH overhead from PS 0/0 kbps users


– DPCCH overhead from PS 0/0 kbps users

– HS-DPCCH overhead for HSUPA

• It is possible to improve the situation because we are not hitting any fundamental theoretical limit. The limit is ”only” system protocol design and configuration. There are already promising indications since RU20 ontop releases have stabilized the uplink in many networks.

• NSN uses interference based uplink RRM while some RAN vendors use throughput based solution (number of users). The interference based solution has the benefit that cell breathing can be controlled. But interference based solution requires also careful control of the uplink interference sources to provide optimal performance.

NSN Solutions for Uplink Interference Control – Summary

HS-RACH

Interference cancellation

Dynamic HSUPA power offset RU20

RU30

RU40

Cell_PCH

Load aware outer loop power control RU30

3GPP Release 99-6

HSUPA DPCCH interpolation RU30

Fast dormancy RU20

High noise optimized RRM1 RU20

High noise

Cell level control of uplink parameters RU30

3GPP Release 7

Continuous packet connectivity RU20

3GPP Release 8

RACH access class


High noise optimized RRM2 RU20

Dynamic initial bit rate allocation RU20

DPCCH overhead calculation RU20

Downgrade of DCH in SHO congestion RU20

RRC IPhone workaround RU20

Fast BTS load control

RACH access class barring RU40

Dynamic parameter settings

Dynamic CQI frequency

Dynamic HSUPA Power Offset

DynPwrOffsetTable2 (High/low power offset indication table for 2ms TTI)

RSCP [dBm] EcNo [dB]

< -108 < - 14 L L L L L L

-105…-108 -13…-14 L L L L L L

• Two sets of DPCCH offset values defined. Lower DPCCH power is used when the condition(H=High load) is fulfilled


-105…-108 -13…-14 L L L L L L

-101…-104 -11…-12 L L L L L L

-98..100 - 10 H H L L L L

-98..-95 - 9 H H H L L L

> -95 > -9 H H H L L L

0-1 2-3 4-6 7-12 13-20 >20

# of HSPA serving cell

users

High Noise Optimized RRM1

• Five features for optimizing the power based uplink RRM

• Correction of the filtering parameter MaxIncrInterferenceUL

• Filter out the short term spikes of the measured RTWP for avoiding the unnecessary admission control blockings during the period of the spike

• Corrections in power increase and decrease estimations of the estimated R99 power

• Correction of the power increase and decrease estimations in the HSUPA cells


• Correction of the power increase and decrease estimations in the HSUPA cells

• Reference power of the management parameter DeltaPrxMaxUp

• Reduction of the SIR target values for the PS HSPA calls

Initial SIR Target Optimization

Parameters 1-RX 2-RX 4-RX nonSHO SHO beta_d / beta_c R_b

SIRDPCCHInitialDCHHS256 4.5 2.5 -0.5 -1.5 1.3 2.0

SIRDPCCHInitialDCHHS128 4.5 2.5 -0.5 -1.5 1.3 2.0 1.2 16 kbps

SIRDPCCHInitialDCHHS64 4.5 2.5 -0.5 -1.5 1.3 2.0

SIRDPCCHInitialDCHHS32 6.0 4.0 1.0 0.0 1.3 2.0 1.4 64 kbps


SIRDPCCHInitialDCHHS8 8.0 6.0 3.0 2.0 1.0 1.6


SIRDPCCHInitialDCH64 4.5 2.5 -0.5 -1.5 1.2 AMR 12.2

Initial DPCCH SIR w HSDPA AmplitudeRatioACK

SIRDPCCHInitialDCHOffset -2 dB

SIRDPCCHInitialDCHRxDiv2 -3 dB

SIRDPCCHInitialDCHRxDiv4 -4 dBSIRDPCCHInitialDCHMax 6 dB

SF DPCCH 256

Graphs are assuming activity factor as given below: 16kbps – 63%, 64kbps – 16%, 384kbps – 3%

Original Defaults New Recommendation


/

UL noise rise at initial SIR with DPCCH and HS-DPCCH overhead

0

1

2

3

4

5

6

7

8

9

10

1 3 5 7 9 11 13 15 17 19 21 23 25

Number of links (DPCCH + HS-DPCCH + DPDCH)

UL n

ois

e ris

e (dB)

16 kbps

64 kbps

384 kbps

UL noise rise at initial SIR with DPCCH and HS-DPCCH overhead

0

1

2

3

4

5

6

7

8

9

10

1 3 5 7 9 11 13 15 17 19 21 23 25

Number of links (DPCCH + HS-DPCCH + DPDCH)

UL n

ois

e ris

e (dB)

16 kbps

64 kbps

384 kbps

Original Defaults New Recommendation

High Noise Optimized RRM2

• 12 features for optimizing the power based uplink RRM

• Emergency call failure for the power blocking

• PrxNoise autotuning only in the cell without any CELL_DCH traffic

• PrxNoise is autotuned only if all cells of the same frequency in the BTS are on the low traffic level

• Adjusting of the increased reference noise floor value in the loaded cell

• Detection of the common measurement reports filtered by BTS


• Candidate prioritization and bit rate selection in PBS

• R99 Overload Control procedure

• Downgrading the PS NRT DCH for the soft handover branch addition congestion handling

• PRFILE parameter control for triggering the channel type switching from the SIR error

• Limited value of UL DPCCH power offset for the first RL setup in the RTWP spiking cell

• Power based Admission Control for the HSUPA call setups

• Correction in updating the the MIN and MAX PRXTOTAL counters of the Received Rel99 wideband power measurement

Dynamic Initial Bit Rate Allocation

• Allows more PS NRT users admitted at initial and minimum bit rates in and keep the existing PS NRT users longer in the CELL_DCH state.

• High bit rate PS DCH users are selected first for downgrade, the QoS priority is applied only when the PS calls of the cell are not using higher than the initial DCH bit rates

• PBS candidates will be prioritized in all congestion cases as follows:

• PS NRT DCHs users having higher bit rate than initial bit rate users, in the QoS priority order.

• PS NRT DCHs users having higher bit rate than minimum bit rate users, in the QoS priority order.


• PS NRT DCHs users having higher bit rate than minimum bit rate users, in the QoS priority order.

• Finally the minimum bit rate users, in the QoS priority order.

• Initial/minimum DCH bit rate selection of the PS call triggered the PBS:

• New functionality applies to the UL interference, DL power and UL load congestion.

• If BRM detects congestion and the PBS triggers, then:

• If high bit rate (higher than initial) PBS candidates are available, then the incoming user gets the initial bit rate

• If only low bit rate (lower or initial) PBS candidates are available, then the incoming user gets the minimum bit rate.

Downgrading NRT DCH in Soft Handover Congestion

• Present implementation does not allow the downgrading of the DCH bit rates of the PS bearers if a congestion occurs in the soft handover branch addition. If the target cell is better than the ones in the active set, the failed soft handover may cause significant spiking of the RTWP, unless the PS DCH is removed.

• In the new implementation, the PS DCH is downgraded to the minimum bit rate and then attempted the branch addition once more.

• If the congestion occurs still, the UE is switched to CELL_FACH state without applying the management parameter EnableRRCRelease. If the UE has also the AMR, the PS bearers are


management parameter EnableRRCRelease. If the UE has also the AMR, the PS bearers are downgraded to DCH 0/0 as it is done already in the original implementation.

• Function is similar if the congestion occurs in the soft handover branch addition over the Iur.

RRC IPhone Workaround UE 1 Cell1 RNC

RACH: RRC: RRC Connection Request

UE starts decoding FACH

FACH: RRC: RRC Connection Setup, state indicator: Cell-DCH (Spreading code 1)

RACH: RRC: RRC Connection Request cause: protocol error

UE decodes some rubbish from FACH

RNC thinks first RRC connection request has

RL setup procedure, spreading code1

UE 2Cell1

Solution: RNC ignores the repeated RRC connection request with protocol

error cause and wait for the RRC connection setup complete for the first

RRC connection setup.


RNC thinks first RRC connection request has

failed, and releases resources, and setup resources for second RRC connection request

RL deletion procedure, spreading

code 1

RL setup procedure, spreading code2

FACH: RRC: RRC Connection Setup state indicator: Cell-DCH (Spreading code 2)

RNC allocates spreading code1 to UE2

UE decodes first RRC Connection

setup message, and starts using spreading code 1 in Cell_DCH state

UE1 and UE2 decoding the same DL spreading code

and TPC bits. UE1 can cause uncontrolled interference.

DCH: RRC: RRC Connection Setup Complete spreading code 1

DPCCH Overhead Calculation

• DPCCH overhead included in load factor estimation has too conservative value based on initial UL SIR target. This modification multiplies the initial SIR target value with the activity factor of the signaling link DCH.


Interference Cancellation

• Estimate the physical channel data after channel (Turbo) decoding. The physical channel data is generated by encoding the decoded data. Large gain from channel decoding

• Uplink throughput gain 23-62%

• SW upgrade to Flexi Rel.2 baseband

ROT = 6 dB ROT = 8 dB


RXRX RAKERAKE

ICIC DECODERDECODERRAKERAKE

DECODERDECODER ENCODERENCODER

no PIC PIC

PIC

(uncod.) PIC

PIC

(uncod.) no PIC PIC

PIC

(uncod.) PIC

PIC

(uncod.)

1 user 5,84 7,61

2 user 4,78 5,92 5,92 24% 24% 5,53 7,69 7,69 39% 39%

3 user 3,96 5,87 5,39 48% 36% 4,29 6,93 6,19 62% 44%

thrput Mbps trp gain thrput Mbps trp gain

ROT = 6 dB ROT = 8 dB

Cell Level Control of Uplink Parameters

• Some of the existing UL interference impacting parameters that are controlled in RNC level, change to cell level

• HSDPAinitialBitrateUL

• HSDPAminallowedBitrateUL

• TrafVolPendingTimeDL

• TrafVolPendingTimeUL



• Prx NoiseMaxTuneAbsolute

• WaitTimeRRC

Load Aware of Outer Loop Power Control

• Target: prevent too high increase of SIR target during high load

• Reason: SIR target increases if UE hits its max power

• Freeze AMR SIR targets and decrease NRT PS SIR targets until noise rise gets lower

• Potentially also decrease AMR SIR and/or increase BLER target with higher noise rise


RACH Access Class Barring

• The access classes [0,…9] which are barred are actually rotated by specified intervals.

• If during first time interval, the access classes [1,2,3] were barred, in the next time interval [4,5,6] would be barred covering access classes 0,…,9, i.e. rotation by mod 10. Rotation time needs to be long enough.


-0.1

0

Fast BTS Load Control

• Reduce SIR target if noise rise exceeds PrxTarget + offset (2 dB)

( )

( )10

_

,_

arg,

,arg,arg

arg,

OffsetPriseNoiseSIRSIR

OffsetPriseNoiseIf

ettrx

RNCettBTSett

ettrx

−−−=

+>


0 2 4 6 8 10 12 14 16 18 20-1

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

Noise rise [dB]

SIR

targ

et

corr

ection [

dB

]

PrxTarget 8 dB

SIR target

adjustment

Dynamic Parameter Setting

• High interference cases can be solved by using suitable timer and other parameters during mass events. Some of those parameters are not good for the non-congested cells. Therefore, the parameters should be automatically tuned according to the instantaneous load.

• Example parameters

• WaitTimeRRC




Dynamic CQI Frequency

• Channel Quality Information (CQI) frequency is 4 ms currently

• CQI frequency could be lowered during high uplink load to minimize the interference in the same way as DPCCH offset values are optimized

• Current CQI interference contribution with 4 ms period = 0.41 x DPCCH. If we would lower CQI frequency to 10 ms or 20 ms, the interference would reduce to 0.08..0.16 x DPCCH.

• The total uplink interference from HSDPA users without any uplink activity would be reduced be 1-(1+0.08)/(1+0.41) = 23%


be 1-(1+0.08)/(1+0.41) = 23%

A/N CQIA/N CQI

DPCCH

HS-DPCCH

DPCCH

A/N CQI CQI power offset –2 dB in

single link and +4 dB in SHO

compared to DPCCH

Continuous Packet Connectivity

• Uplink DPCCH and E-DPCCH gating reduces interference especially for low data rate users

• Gating is part of Continuous packet connectivity (CPC). It is part of 3GPP Release 7

300

400

500

600

700

800

900

1000

1100

1200

1300

Cell T

hro

ug

hp

ut

(kb

ps)

PedA_not gated

PedA_9/15300

400

500

600

700

800

900

1000

1100

1200

1300

Cell T

hro

ug

hp

ut

(kb

ps)

PedA_not gated

PedA_9/15

PedA_not gated

PedA_9/15


(E-)DPCCH

E-DDCH

Web page download

User reading web page

0

100

200

300

0 5 10 15 20 25 30 35 40 45 50 55

Number of no-data UEs in CELL_DCH

Cell T

hro

ug

hp

ut

(kb

ps)

PedA_9/15

PedA_12/15

PedA_9/15 ideal

PedA_12/15 ideal0

100

200

300

0 5 10 15 20 25 30 35 40 45 50 55

Number of no-data UEs in CELL_DCH

Cell T

hro

ug

hp

ut

(kb

ps)

PedA_9/15

PedA_12/15

PedA_9/15 ideal

PedA_12/15 ideal

PedA_9/15

PedA_12/15

PedA_9/15 ideal

PedA_12/15 ideal

HSUPA DPCCH Interpolation

• Release 7 solution allows to minimize DPCCH overhead for low data rate HSUPA users

• Fixed DPCCH power in Release 6 leads typically to too high DPCCH overhead at low kbps

Optimised

gain factors

E-TFC

[kbps]

Pred

[dB]

Relative power of E-DPDCHs over DPCCH

2 ms TTI

16

18

P(E

-DP

DC

Hs

) [d

B]


[kbps] [dB]

32 6

64 7.1

128 8.1

256 8.9

384 9.9

512 8.1

768 8.1

1024 6

1450 6

1920 6

2900 7.1

3800 8

4

6

8

10

12

14

16

0

256

512

768

1 02

41

280

1 53

61

792

2 04

82

304

2 56

02

816

3 07

23

328

3 58

43

840

4 09

6

Data rate [kbps]

P(E

-DP

DC

Hs

) [d

B]

Computed P(E-DPDCHs)

Optimal P(E-DPDCHs)

Fast Dormancy

Other vendors

2 s IDLEIDLE

DCH/HSPA inactivity timer

CELL_FACH inactivity timer30 signalingmessages

Heavy signaling load Low battery life time

Idle = <5 mA

Cell_PCH = <5 mA

Cell_FACH = >100 mA

Active = >200 mA

IDLE

Fast Dormancy to save battery


Nokia Siemens Networks

<0.3 s

3 signalingmessages

2 s

PCH PCH

DCH/HSPA inactive

CELL_FACH inactive12 signalingmessages

Idle = <5 mA

Cell_PCH = <5 mA

Cell_FACH = >100 mA

Active = >200 mA

Network avoids signaling stormBattery lasts longer

HS-RACH

• HS-RACH allows carrying medium size data packets without allocation of dedicated resources

kB per DCH or HS-DSCH Allocation315

199

160180200220240260280300320

• The avarage data volume per allocation is typically 10-60 kB for the smartphones. The median value is even smaller: 60% of allocations are below 1 kB ⇒ largepart of smartphone traffic could becarried by HS-RACH


47

25

46506868

3238

2

3414

44

212

155 1116

117

12 8

100

65

2034

6 1413112320

5 1 2 4 3 6 3

78

17

94

1 8 15

53

020406080

100120140160

Ap

ple

iP

ad 3

G (

A1

33

7)

Ap

ple

iP

hon

e 3

G (

A1

24

1)

App

le iP

hone

3G

A1

24

1

Ap

ple

iP

hon

e 3

G S

- A

130

3

Ap

ple

iP

hon

e 3

G S

(A

130

3)

App

le iP

ho

ne 3

GS

A1

30

3

Apple

iP

ho

ne 4

(A

133

2)

AS

US

Te

k

N³v

ifo

ne A

50

HT

C D

RE

A11

0

HT

C D

esire

HT

C H

ero

HT

C L

eg

en

d

HT

C W

ildfire

HT

C M

AP

L11

0

HT

C P

B9

220

0

HT

C P

B9

910

0

HT

C P

B9

921

0

HT

C P

D9

81

00

Hu

aw

ei E

16

0E

Huaw

ei E

169

Hu

aw

ei E

17

62

LG

GT

54

0

Moto

rola

MB

501,

ME

501

No

kia

E5-0

0

No

kia

E63

-1

No

kia

E71

-1

No

kia

E72

-1

No

kia

N97

-4

Nokia

No

kia

E63

-1

Nokia

No

kia

E71

-1

Nokia

No

kia

E72

-1

Nokia

No

kia

N8-0

0

Qis

da

Str

eak

RIM

900

0

RIM

930

0

RIM

970

0

RIM

97

00

(G

ene

ric)

RIM

978

0

RIM

Bla

ckbe

rry 9

800

Sam

su

ng

GT

-I58

00

Sam

su

ng

GT

-I87

00

Sam

su

ng

GT

-I90

00

Sam

sung

Sam

su

ng

GT

-I900

0

Sie

rra

Wire

less M

C87

75V

Son

y E

ricsson

E10

i

Sony E

ricsson X

10i

Sony E

ricsson X

10i

carried by HS-RACH

• HS-RACH reduces controloverhead considerably

• No setup signalling

• Immediate stop of controlchannel transmission compared to DCH with >1 second timer

Summary

• 3G networks have turned to be uplink limited due to interference limited nature of CDMA uplink. The main problems come from the control channel and signalling overhead which is driven by increased smartphone traffic and HSUPA high data rates

• NSN has introduced a large number of features in RU20 and RU30 to improve the uplink performance. The features have already shown to be highly useful in the practical networks.


• NSN has been active in 3GPP to improve the system performance

NSN 3G Uplink Optimization

Documents

Transcript of NSN 3G Uplink Optimization