263361913 nsn 3g uplink optimization by Emerson Rodrigues Setim

Nokia Siemens Networks â&#x20AC;&#x201C; 3G Uplink Optimization NSN response to Annex 6, Chapter 5 in T-Mobile Netherlands Single RAN RfQ September 2011

ÂŠ Nokia Siemens Networks 2011

Customer Confidential

Introduction Target 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. Confidentiality All information related to the Nokia Siemens Networks 3G Uplink Optimization features, functionalityâ&#x20AC;&#x2122;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.

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Customer Confidential

Uplink vs Downlink Traffic in Live 3G Networks (1) HSUPA / HSDPA daily volume ratio at selected operators 0.25

Europe 1

0.20

South America Europe 2

0.15

MEA Europe 3

0.10

• 0.05

• 0 01.03.2010

01.07.2010

01.10.2010

01.01.2011

Source: NSN Analysis, April 2011

Customer Confidential

01.04.2011

Uplink traffic volume is 1520% of downlink Uplink volume is growing faster than downlink (due to HSUPA)

Uplink vs Downlink Traffic in Example Live 3G Network HSDPA vs HSUPA ratio 10x now and getting smaller due to higher HSUPA penetration

Â© Nokia Siemens Networks 2011

HSDPA vs HSUPA + WCDMA UL ratio 6x and stabile

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Uplink vs Downlink Capacity in Theory

• •

Evolution of HSPA efficiency

1.74

Downlink Uplink

1.44

1.31

0.53

0.65

0.79

Customer Confidential

LTE R8

HSPA R10 QCHSDPA+MIMO

0.33

HSPA R8 DCHSDPA

0.33

HSPA R7 64QAM

0.55 0.33

1.52

1.11

HSPA R9 DCHSDPA+MIMO

1.06

HSPA R6 + UE equalizer

2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0

HSPA R6

bps/Hz/cell

•

Downlink 1.31 bps/Hz/cell Uplink 0.33 bps/Hz/cell (0.53 with IC) => Theoretical ratio 4x

Smartphones Increase Signalling Load •

More multi-RABs due to smartphones

• Smartphones create frequent transmission of small packets which requires frequent RRC state changes (DCH allocations) and RACH signalling which increases uplink interference

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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 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. © Nokia Siemens Networks 2011

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NSN Solutions for Uplink Interference Control – Summary 3GPP Release 99-6 Cell_PCH

3GPP Release 7

Interference cancellation

RU30

Continuous packet connectivity

RU20

Fast dormancy

RU20

HSUPA DPCCH interpolation

RU30

HS-RACH

RU40

Dynamic HSUPA power offset

RU20

Cell level control of uplink parameters

RU30

High noise optimized RRM1

RU20

Load aware outer loop power control

RU30

High noise optimized RRM2

RU20

RACH access class barring

RU40

Dynamic initial bit rate allocation

RU20

Fast BTS load control

Downgrade of DCH in SHO congestion

RU20

Dynamic parameter settings

RRC IPhone workaround

RU20

Dynamic CQI frequency

DPCCH overhead calculation

RU20

3GPP Release 8

Customer Confidential

Dynamic HSUPA Power Offset • Two sets of DPCCH offset values defined. Lower DPCCH power is used when the condition (H=High load) is fulfilled DynPwrOffsetTable2 (High/low power offset indication table for 2ms TTI) RSCP [dBm]

EcNo [dB]

< -108

< - 14

-105…-108

-13…-14

-101…-104

-11…-12

-98..100

- 10

-98..-95

-9

> -95

> -9

0-1 9

2-3

4-6

Customer Confidential

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 Reference power of the management parameter DeltaPrxMaxUp Reduction of the SIR target values for the PS HSPA calls

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Initial SIR Target Optimization Parameters SIRDPCCHInitialDCHHS256 SIRDPCCHInitialDCHHS128 SIRDPCCHInitialDCHHS64 SIRDPCCHInitialDCHHS32 SIRDPCCHInitialDCHHS16 SIRDPCCHInitialDCHHS8 SIRDPCCHInitialDCHHS4 SIRDPCCHInitialDCH64

4.5 4.5 4.5 6.0 7.5 8.0 9.0 4.5

Initial DPCCH SIR w HSDPA AmplitudeRatioACK 1-RX 2-RX 4-RX nonSHO SHO beta_d / beta_c 2.5 -0.5 -1.5 1.3 2.0 2.5 -0.5 -1.5 1.3 2.0 1.2 2.5 -0.5 -1.5 1.3 2.0 4.0 1.0 0.0 1.3 2.0 1.4 5.5 2.5 1.5 1.0 1.6 1.7 6.0 3.0 2.0 1.0 1.6 7.0 4.0 3.0 0.8 1.3 2.5 2.5 -0.5 -1.5 1.2

R_b

SIRDPCCHInitialDCHOffset SIRDPCCHInitialDCHRxDiv2 SIRDPCCHInitialDCHRxDiv4 SIRDPCCHInitialDCHMax SF DPCCH

16 kbps 64 kbps 128 kbps

-2 -3 -4 6 256

dB dB dB dB

384 kbps AMR 12.2

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 10

Customer Confidential

Num ber of links (DPCCH + HS-DPCCH + DPDCH)

0 15

0 13

384 kbps

64 kbps

384 kbps

16 kbps

64 kbps

16 kbps

UL noise rise (dB)

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

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 © Nokia Siemens Networks 2011

Customer Confidential

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. • 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. 13

Customer Confidential

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 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.

Customer Confidential

RRC IPhone Workaround UE 1

Cell1

RNC

Cell1

UE 2

RACH: RRC: RRC Connection Request UE starts decoding FACH RL setup procedure, spreading code1 FACH: RRC: RRC Connection Setup, state indicator: Cell-DCH (Spreading code 1) UE decodes some rubbish from FACH

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.

RACH: RRC: RRC Connection Request cause: protocol error RNC thinks first RRC connection request has failed, and releases resources, and setup resources for second RRC connection request

UE decodes first RRC Connection setup message, and starts using spreading code 1 in Cell_DCH state

RL deletion procedure, spreading code 1 RL setup procedure, spreading code2 RNC allocates spreading code1 to UE2

FACH: RRC: RRC Connection Setup state indicator: Cell-DCH (Spreading code 2) DCH: RRC: RRC Connection Setup Complete spreading code 1

UE1 and UE2 decoding the same DL spreading code and TPC bits. UE1 can cause uncontrolled interference. 15

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Customer Confidential

DPCCH Overhead Calculation â&#x20AC;˘ 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.

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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 thrput Mbps trp gain thrput Mbps trp gain PIC PIC PIC PIC (uncod.) (uncod.) no PIC (uncod.) (uncod.) no PIC PIC PIC PIC PIC 1 user 2 user 3 user

5,84 4,78 3,96

5,92 5,87

RAKE

5,92 5,39

24% 48%

DECODER

24% 36%

7,61 5,53 4,29

7,69 6,19

39% 62%

39% 44%

ENCODER IC

7,69 6,93

RAKE

DECODER Customer Confidential

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

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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

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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.

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Fast BTS Load Control •

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

If (Noise _ rise ) > Prx ,t arg et + Offset , SIRt arg et , BTS = SIRt arg et , RNC −

(Noise _ rise − P

rx ,t arg et

− Offset )

0 -0.1

SIR target correction [dB]

-0.2

SIR target adjustment

-0.3 -0.4 -0.5

PrxTarget 8 dB

-0.6 -0.7 -0.8 -0.9 -1

8 10 12 Noise rise [dB]

Customer Confidential

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 • TrafVolPendingTimeUL

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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%

HS-DPCCH

A/N

DPCCH

CQI

A/N

CQI

A/N

DPCCH

Customer Confidential

CQI

CQI power offset –2 dB in single link and +4 dB in SHO compared to DPCCH

Continuous Packet Connectivity reduces interference especially for low data rate users • Gating is part of Continuous packet connectivity (CPC). It is part of 3GPP Release 7

Web page download

Cell Throughput (kbps)

• Uplink DPCCH and E-DPCCH gating

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

User reading web page

Number of no-data UEs in CELL_DCH

E-DDCH (E-)DPCCH

PedA_not gated PedA_9/15 PedA_12/15 PedA_9/15 ideal PedA_12/15 ideal

Customer Confidential

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 Relative power of E-DPDCHs over DPCCH 2 ms TTI

18 16 14 12 10 8 6 4

Data rate [kbps]

Customer Confidential

09 6 4

84 0 3

58 4 3

32 8 3

07 2 3

81 6 2

56 0

30 4 2

04 8 2

79 2 1

53 6 1

28 0 1

02 4 1

76 8

51 2

Computed P(E-DPDCHs) Optimal P(E-DPDCHs) 25 6

Pred [dB] 6 7.1 8.1 8.9 9.9 8.1 8.1 6 6 6 7.1 8

E-TFC [kbps] 32 64 128 256 384 512 768 1024 1450 1920 2900 3800

P(E-DPDCHs) [dB]

Optimised gain factors

Fast Dormancy Other vendors DCH/HSPA

Active = >200 mA Cell_FACH = >100 mA

30 signaling messages IDLE

Nokia Siemens Networks

inactivity timer CELL_FACH

inactivity timer

Fast Dormancy to save battery

Cell_PCH = <5 mA Idle = <5 mA

Heavy signaling load Low battery life time

IDLE

Network avoids signaling storm Battery lasts longer

DCH/HSPA inactive

Active = >200 mA Cell_FACH = >100 mA Cell_PCH = <5 mA Idle = <5 mA

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12 signaling messages

CELL_FACH

3 signaling messages

PCH

<0.3 s

Customer Confidential

inactive

PCH

allocation is typically 10-60 kB for the smartphones. The median value is even smaller: 60% of allocations are below 1 kB ⇒ large part of smartphone traffic could be carried by HS-RACH • HS-RACH reduces control overhead considerably • No setup signalling • Immediate stop of control channel transmission compared to DCH with >1 second timer

Apple iPad 3G (A1337) Apple iPhone 3G (A1241) Apple iPhone 3G A1241 Apple iPhone 3G S - A1303 Apple iPhone 3G S (A1303) Apple iPhone 3GS A1303 Apple iPhone 4 (A1332) ASUSTek N³vifone A50 HTC DREA110 HTC Desire HTC Hero HTC Legend HTC Wildfire HTC MAPL110 HTC PB92200 HTC PB99100 HTC PB99210 HTC PD98100 Huawei E160E Huawei E169 Huawei E1762 LG GT540 Motorola MB501, ME501 Nokia E5-00 Nokia E63-1 Nokia E71-1 Nokia E72-1 Nokia N97-4 Nokia Nokia E63-1 Nokia Nokia E71-1 Nokia Nokia E72-1 Nokia Nokia N8-00 Qisda Streak RIM 9000 RIM 9300 RIM 9700 RIM 9700 (Generic) RIM 9780 RIM Blackberry 9800 Samsung GT-I5800 Samsung GT-I8700 Samsung GT-I9000 Samsung Samsung GT-I9000 SierraWireless MC8775V Sony Ericsson E10i Sony Ericsson X10i Sony Ericsson X10i

HS-RACH

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

• The avarage data volume per

315 320 300 280 260 240 220 199 200 180 160 140 117 120 100 94 100 78 6868 65 80 53 44 60 47 46 50 34 32 38 34 25 23 40 20 20 17 15 14 21 15 11 16 12 8 6 14 13 11 5 1 2 4 3 6 3 5 20 2 2 1 8 0

kB per DCH or HS-DSCH Allocation

Customer Confidential

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

Customer Confidential