8.aitor garcia vinas

1 VODAFONE C3 CONFIDENTIAL

Understanding how Vodafone Spain are managing their HSPA network to ensure optimum performance

Mobile Network Optimisation

Vienna 6th‐9th June 2011

Aitor Garcia Viñas

–

[email protected]

Vodafone Spain – Access Department

mailto:[email protected]


THE WAY WE HAVE BEEN SEEING THE NETWORK IS CHANGING

SMARTPHONES ARE THERE


SMARTPHONE EVOLUTION IN VODAFONE SPAIN

sep-10 oct-10 nov-10 dic-10 ene-11

M B/M onth Device Number

Smartphone Evolution in Vodafone Spain

+14%+65%


Understanding traffic mix and profiles in an existing HSPA

network to

improve HSPA Data performance

21%

31%

48%

95.74%

0.36%3.89%

Smartphones & modem data traffic

modem

mobile phone

smartphone

% devices with PS traffic

% total traffic


Understanding Device Requirements

•Mobile Phones:–

Voice quality and mobility

•Modems:–

User peak and average throughput

–

RNC data traffic processing load

–

DL interference

•Smartphones:–

Number of simultaneous users

–

RNC signalling processing load

–

UL interference

XXXXXX

RRU

Antenna

BBU

RNC

Node B

Different capacity issues depending on device type

Mobile Phones Modems Smartphones

MARKET DIRECTION

VOICE

DATA

VOICE + DATA


Understanding Capacity Requirements

•Capacity Improvement in DL: More steps

and more resources (power and codes)

•Better optimised for multi‐user

•Capacity Improvement in UL: Less and bigger

steps than in DL

•Simultaneous user affects significantly the

cell capacity

•Baseband consumption is very demanding

714

21

4228

84

10 codes 16QAM

15 codes 16QAM

Multi Carrier

MIMO

15 codes 64QAM

Combinations

2

5.7

11.5

10ms

2ms

Multi Carrier or 16QAM

Multi Carrier + 16QAM22


DL Cell Capacity and User Performance Enhancement

Dl

R99

HSDPA+ 64QAM

HSDPA 16QAM

11

0100

10

1111

111111

Scheduler

&

TFRC

Selection

HARQ

HARQ

Turbo

encoder

Turbo

encoder

Modulation

Spreading

Scrambling

Modulation

Spreading

Scrambling

•W11

•W12

•W21

•W22

•P‐CPICH

•S‐CPICH

Precoding

matrix

calculation

•W1•W2•W3•W4

•Pre‐coding control info•(PCI) from UE

R99 R99/HSDPA

R99

R99/HSDPA

R99/HSDPA+

R99/HSDPA+

5, 10 , 15 codes

5, 10 , 15 codes 15 codes

HSDPA+ WORLD: 64QAM, MIMO and Carrier Aggregation

MIMO 28.8Mbps

MULTI CARRIER 42.2Mbps

DUAL CARRIER +MIMO Up to

84Mbps

64QAM

21.8Mbp

s

384kbps Up to 10.8Mbps

Up to

84Mbps


Inter‐carrier Load Sharing vs

Non‐Load Sharing

•

15% CS Call drop rate improvement in

Smartphones

•

50% PDP Context activation time

•

Throughput improvement in node B

with high load: +15% DL and +10% UL *

•

Downlink and Uplink Noise distributed in

both layers

R99/HSDPA+

R99/HSDPA+ Cell barred

Any HSPA call to F2No HSPA call established in F1No interfreq

reselection

F2

F1 R99/HSDPA+

R99/HSDPA+

Full HSPA&R99 load balanceInterfreq

resel. allowed

F2

F1

Voice Only layer

HSPA and MRAB Layer

Complete sharing of traffic 50%/50% obtained unbarring F2 and making use of full load sharing

* Benefit seen by drive test

All users camp in F1PS Redirection to F2

Voice and data

redirection and

reselection

based on load

and quality


HSPA+ 64QAM, MIMO and Dual Carrier

Throughput Comparison at Different Radio Conditions (Mbps)

6.1

2.5

9.0

3.5

20.7

9.6

5.1

21.0

11.1

5.1

10.8

14.2

Good Radio Medium Radio Bad Radio

HSPA + 64QAMHSPA+ MIMOHSPA+ Dual Carrier 64QAM (20W)HSPA+ Dual Carrier 64QAM (40W)

Spectrum Efficiency Comparison at different Radio Conditions (Bits/Hz)

1.2

2.2

0.7

1.8

2.8

0.5

1.0

2.1

0.5

1.1

2.1

0.5

Good Radio Medium Radio Bad Radio

HSPA+ 64QAMHSPA+ MIMOHSPA+ Dual Carrier 64QAM (20W)HSPA+ Dual Carrier 64QAM (40W)

•

HSPA+ DC almost doubles HSPA+ 64QAM

throughput

•

MIMO sometimes unstable in good radio

•

Impact on legacy users due to MIMO data

and S‐CPICH Channel

•

40W Power availability performance

improvement not significant

•

But best spectrum efficiency for MIMO: highly

advisable for high loaded scenarios where DC

reduces its performance

Note: Tests performed on a cluster having average traffic load

according to VF‐ES traffic profile performing FTP downloads


Enhanced Virtual Antenna Mapping to cope with MIMO 2

VAM

matrixPA2

PA1∑

Rel’99 / HSMIMO stream #1

Primary Pilot

∑MIMO stream #2

Secondary Pilot

V1

V2

Virtual Antennas

(what the UE believes is transmitted)

Physical Antennas

(what the UE is actually transmitted)

Ant 1

Ant 2

θPhase adaptation to

Optimise power received

by HSPA users

CQI reporting from HSPA users

E-VAM algorithm

Enhanced VAM (E-VAM)

allows to dynamically control the phase offset between with the following objectives:

1)

Minimise interference from MIMO2 (virtual antenna 2 signals seen as interference for HSPA users).

2)

Maximise the throughput of HSPA legacy users (independently from MIMO).

Enhanced VAM (E-VAM)

was developed to build upon the partial

success of VAM by insertion of phase after

the signal passes the VAM matrix to one

of the output ports only


eVAM

to cope with MIMO 2 and improve coverage

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

cdf (

%)

CQI

E-VAM

VAM

E‐VAM activated at BH in VF

ES commercial Network with

high HSDPA traffic load with

no MIMO users present

Around 0.8dB average CQI

improvement achieved

0

5

10

15

20

25

Baseline ‐ 7.2 Mbps "14.4" Mbps MIMO HS ‐ HS HS ‐ MIMO VAM HS ‐ MIMO E‐VAM MIMO ‐ MIMO

user 2user 1

Mbp

s

single active user concurrent active users

DL throughput (good radio conditions)

Legacy throughput

degradation due to

MIMO 2


UL Cell Capacity and User Performance Enhancement

1.

Rake Receiver:

Place fingers on path delays Maximise Self Power

2.

Equaliser Receiver:

Add extra fingers to suppress the self interference Combat self interference

3.

Time Division Mux

Receiver:

Allocate different TTIs

to each user Combat intra‐cell interference + Interference Cancellation Receiver: Suppress dominant intra‐ and inter‐cell interference Maximise received SIR

4.

Dynamic Noise level and BLER target Increase cell capacity adapting to user location and traffic mix

5.

16QAM Increase spectrum efficiency + Multi Carrier Increase peak and average user throughput

2 4 51 3

TIMETODAY

Up to 3.2Mbps Up to 4Mbps Up to 6Mbps ? Mbps (Max 21 Mbps)


UL Expected Cell Capacity in multi‐user environment

2ms HSUPA User

10ms HSUPA User

2ms User Mix 10ms User Mix 2ms + 10ms User Mix

•

Significant cell capacity reduction with the 3rd user in the system

•

UL Cell capacity will depend on user location and 2ms to 10ms HSUPA user traffic mix due to

scheduler fairness

•

No Capacity gain when putting 3x2ms users vs

having 10ms in the system

Expected Max cell capacity 10ms: 1 user 1.7 Mbps, 2 user: 2.4 Mbps, 3 user 2MbpsExpected Max cell capacity 2ms: 1 or 2 user 4Mbps, 3 user: 3Mbps, 4 user 2Mbps

1


UL Receiver Equaliser and SIR Optimisation

2ms HSUPA Average Application Throughput comparison with Equaliser and SIR

•Equaliser benefit depends on layer type and traffic mix: over 8%

•Power control optimisation improves over 20% the average throughput

2


UL Interference Cancellation

+12%

+61% +51% +28%

•

Cell throughput gain between 12% and 61% depending on HSUPA user

combination

•

Major increase observed for HSUPA 5.76Mbps when HSUPA 2Mbps user

throughput is near its

achievable maximum rates (1.7Mbps)

2ms HSUPA User

10ms HSUPA User

3 x 10ms Use

rs

1 x 10

ms + 1 x 2ms Use

rs

2 x 10ms + 1 x 2ms Use

rs

2 x 2m

s Use

rs

Interference Cancellation feature benefits for different types of user mix

3


DL and UL Short Term Key Features: Fast Dormancy

•

Fast Dormancy enables the direct transition to cell‐PCH from

cell‐DCH or cell‐FACH for some specific UE’s

•

Pre‐Rel

8 Fast dormancy can be triggered by two reasons:1.

UE sends RRC Con. release to indicate no more data to send

2.

RNC detects no data from/to the UE during a certain period of time

•

Avoid scenarios with high signaling generated by UE’s

or

Paging channel congestion

•

Battery saving and better user experience

XX

XXX

X

RRU

Antenna

BBU

RNC

Nod

e B

SGSN

GGSN

DL and UL Baseband CE > 10%

Radio Links established > 20%

FACH usage > 7%

Significant Control plane load decrease

Very high #PS

RAB and Paging

reduction

CELL_DCH

CELL_FACH

CELL_PCH

URA_PCH

IDLE

FAST

DORMANCY

Call Drop Rate

increased for

specific UE’s

so

white list based

fast dormancy

generated

Pre or Post Rel‐8

devices


DL and UL Short Term Key Features: Traffic Offload

XX

XXX

X

RRU

Antenna

BBU

RNC

Nod

e B

SGSN

GGSN

WIFI NETWORKINTERNET

Traffic Offload

WIFI OFFLOAD NODE B OFFLOAD RNC OFFLOAD

TYPICAL 3G E2E

DATA CONNECTION

WITH OR WITHOUT

ONE TUNNEL


DL and UL Short Term Key Features: Coverage Improvement

UMTS2100 F2

UMTS900

UMTS2100 F1

Traffic Steering

Traffic SteeringMobility

Mobility

RRU

Passive Antenna

with Macro

equipment

Passive Antenna

With RRUActive Antenna

CARRIER 1CARRIER 2

VERTICAL BEAM FORMING

USER 2

USER 1

HORIZONTAL BEAM FORMING

ACTIVE ANTENNAS

UMTS 900


DL and UL Short Term Key Features: CPC

•UE battery saving gains by allowing to turn off the transmitter and/or receiver

when there is no data

•DL and UL interference level reduction

•Benefit is maximised with users in the system performing little data transmission

as it happens in the Smartphone case

•Live tests show reduction of the UL load in around 2 dB of RSSI

•Trade off of 10ms latency increase

UL DTXDL DRX

DRX Pattern INACTIViTY

TIMER – RX ON RX OFF

time

HS‐SCCH and

E‐AGCH/RGCH

time

DPCCH DPCCH

UL DTX CYCLE

ACK/NACK CQI ACK/NACK ACK/NACK

time

CPC OFF ‐

DPCCH

time


DL and UL Short Term Key Features: HS‐FACH

•Handle more traffic on FACH

•Higher data rate compared to FACH

•More users per cell

•Higher capacity for chatty applications

•Reduce signalling

•Faster up switch FACH ‐> HSPA

•Less Power Consumption

HSPA

HS‐FACHFACH

CELL‐PCH

URA‐PCHIDLE

Data Rates

Power

Connected


The SmartPhone effect….

•Smartphones make many more PS calls, because of "Fast dormancy" handset

behaviour and "Heart Beat" of their applications. These UEs

are very dangerous

because they repeat and repeat connection attempts if they are not successful

•The normal sequence of radio congestion is as follows when the number of

HSUPA users rises, mainly 2ms UL ones–

RTWP rises exponentially; RTWP reaching ‐80dBm begins to degrade BTS sensitivity

–

UEs

use higher and higher power to reach the NodeB/RNC RTWP gets worse

–

UL RRC establishment messages do not arrive to RNC due to high noise UL RTWP

–

UEs

repeat RRC establishment Requests in a loop

–

FACH channel is saturated by high number of RRC Setup messages. RRC Setup messages

are queued and reach Timeout Collapse and “snow ball” effect

–

DL power saturates due to the lack of UL In‐Sync. UL Innerloop

does not converge


Example of Hot Spot: May Puerta

del Sol

Protest (Madrid)

• “Puerta

del Sol”

event ‐> May 17th – 22nd

• Big numbers–

Traffic:–35%

in case of voice and 50%

in case of data more traffic than New Years Eve peak–28%

more voice traffic than the Real Madrid Bernabeu

football match peak

–

Performance:–Accessibility problems at the beginning

of the event due to UL saturation–Dense network changes improved performance and allowed keeping Voice and Data calls

were in 3G

–Voice accessibility above 97%–Data accessibility above 80%

‐> In this case, it is almost transparent for the customer due

to the handset retries it automatically

–Dropped Call Rate

below 1%


Performance Summary in Puerta

del Sol

Voice Accessibility

Voice Erlangs

0%

100%

Voice Accessibility vs

Voice Traffic

0%

100%

Packet Accessibility

Data Traffic

Packet Accessibility vs

Data TrafficUplink Noise Level

Minimum UL Noise

Average UL Noise


Action Summary in Puerta

del Sol, Madrid

•3 Non‐barred Cell Carriers allowing device continuously to camp on best cell

• 15 code with 64QAM HSPA+ capability with 2ms HSUPA

•Over 1000 Channel Element base band capacity per site (for the UL)

•Fast Dormancy with Cell/URA PCH

•Remote Radio Units with 80W power amplifiers

•An Edge based 2G network with Coordinated paging and protected against RACH

storms


Conclusion

•Philosophy and methodology change in terms of network dimensioning due to

smartphone

introduction

•Multi‐RAB CS + PS service more and more important voice and data must be shared, no more need to protect data in dedicated carrier

•Average and peak throughput necessary but mainly reliable fast connection. Multi

Carrier for the short/medium term, MIMO for the long term

•Main target to reduce UL interference level by means of interference cancellation, new features (CPC and HS‐FACH) and network parameter tuning

•Fast dormancy feature critical to avoid too many reestablishment

from idle

26 VODAFONE CONFIDENTIAL 13 June 2011

THANK YOU

8.aitor garcia vinas

Documents

vodafone spainsep

qam throughputmimosom

whspa dual carrier

whspa dcalmostdoubleshspa

8mbps384kbps upto10

codeshsdpa world