Dimensioning, configuration and deployment of Radio Access

Networks.

part 5: HSPA and LTE

HSDPA• Enhanced Support for Downlink Packet Data

– Higher Capacity– Higher Peak data rates– Lower round trip delay time

• Part of release 5• Similar to cdma2000 EV DO• Shared Channel Transmission• Higher order Modulation• Fast Link adaptation• Fast hybrid ARQ• (MIMO to be considered for later releases)

Shared Channel Transmission• Efficient code and power utilization by dynamically sharing radio resources among multiple users

• Time domain (TTI = 2 ms)• Code domain (up to 15 codes)

• Not all UEs are capable to receive data in consecutive TTI (Minimum inter-TTI time > 1)

• CC are not orthogonal due to multipath propagation self interference generated in the cell affecting capacity

Channelization codes allocatedfor HS-DSCH transmission8 codes (example)

SF=16

SF=8

SF=4

SF=2

SF=1

User #1 User #2 User #3 User #4

TTIShared channelization codes

time

HSDPA - Shared channel transmission

Channel coding and throughput

Channel coding at rates 1/4-3/4 – Dynamically changed

Higher order Modulation

• Allows for higher peak data rates– QPSK 480kbps channel bit rate per code– 16QAM 960kbps channel bit rate per code

• Requires higher SNIR– Smaller cells– Shared channel transmission

• Radio channel conditions changes fast due to:– Interference variations– Path loss and shadowing– Multipath fading

• HS-DSCH channel rate control = constant power– Adaptive channel coding– Adaptive modulation (QPSK <-> 16QAM)

• Fast adaptation - TTI=2 ms

• Available rate is adjusted by selecting a Transport Format and Resource Combination (TFRC)

• The achievable rate dependent on:– Available HS power– Radio conditions– UE category– Available # HS codes– 16QAM availability– Load

Fast link adaptation Modulation, coding and data rate

Modulation Coding rate Throughput 5 CC

Throughput10 CC

Throughput15 CC

QPSK

1/4 600 kbps 1.2 Mbps 1.8 Mbps

2/4 1.2 Mbps 2.4 Mbps 3.6 Mbps

3/4 1.8 Mbps 3.6 Mbps 5.4 Mbps

16QAM

2/4 2.4 Mbps 4.8 Mbps 7.2 Mbps

3/4 3.6 Mbps 7.2 Mbps 10.8 Mbps

4/4 4.8 Mbps 9.6 Mbps 14.4 Mbps

SINR vs throughput

• Throughput is a function of modulation, coding and SNIR

RNC

Air interface limitations HW limitations

Channel elementsin NodeB

Transmission(x E1)

- DL power- DL codes- UL interference

Capacity management overview – 3G RAN

384 kbps384 kbps384 kbps

1Mbps0.5Mbps

Power controlConstant bit rate

RNCR99

Power controlled

Power control and rate control

Rate controlConstant DL power

RNCR5

Rate controlled5Mbps3Mbps

384 kbps

Deployment strategy example

f1: R99

Hot spotsDense urban

UrbanSuburban

Rural

Deploymentphase

f2: R99 + HS

f1: R99 + HS

f2: R99 + HS

f1: R99 + HS

f1: R99 + HS

f2: R99 + HS

f1: R99

f1: R99 + HS

Initial phase

Mature phase

LTE – 4G Mobile Broadband

A SHORT SUMMARY ON BEHALF OF ERICSSON

HSPA and LTE = Mobile Broadband

• HSPA – High-Speed Packet Access (”Turbo-3G”)– Gradually improved performance in existing 3G networks

• LTE – Long-Term Evolution (”4G”)– Significantly higher performance and user experience

in a wide range of spectrum allocations– Packet-switched services only– Fulfills IMT-Advanced requirements

Studies Spec’s

LTE LTE-Advanced

HSPA HSPA evolutionHSDPA

2004 2006 20082002

Requirements

WCDMA

2005 2007

Stefan Parkvall

LTE – 4G Mobile Broadband

…via trials…

…to commercial operation!

http://www.teliasonera.com/4g/index.htm

LTE Testbed2007

http://www.ericsson.com/thecompany/press/releases/2009/12/1360881

Testbed 2007, 20 MHz, 2x2 MIMO

12

23

37

54

74

97

123

154

700 m

From early studies…

Rel-9 Rel-10Rel-8

Basic LTE functionality Enhancements & extensions Further extensionsIMT-Advanced compliant

FDD and TDD supportBandwidth flexibility

ICICMulti-antenna supportdata1data2data3data4

Channel-dependent scheduling Hybrid ARQ

OFDM transmission

MBMS Carrier Aggregation

Relaying

Multi-antenna extensionsDual-layer beamforming

Positioning

LTE – Basic Radio-Access Principles

2008 2009 2010

Transmission Scheme

Downlink – OFDM• Parallel transmission on large number of

narrowband subcarriers

Uplink – DFTS-OFDM• DFT-precoded OFDM

› Benefits:– Avoid own-cell interference– Robust to time dispersion

› Main drawback– Power-amplifier efficiency

› Tx signal has single-carrier properties Improved power-amplifier efficiency

– Improved battery life – Reduced PA cost– Critical for uplink

› Equalizer needed Rx Complexity– Not critical for uplink

Cyclic-prefixinsertion

OFDM modulatorDFT precoder

DFT IFFTIFFT Cyclic-prefixinsertion

Multi-antenna Transmission

Diversity for improved system peformance (robustness)

Beam-forming for improved coverage(less cells to cover a given area)

SDMA for improved capacity(more users per cell)

Multi-layer transmisson (”MIMO”) for higher data rates in a given bandwidth

The multi-antenna technique to use depends on what to achieve

Spectrum Flexibility

• Operation in differently-sized spectrum allocations– Core specifications support any bandwidth from 1.4 to 20 MHz– Radio requirements defined for a limited set of spectrum allocations

6 RB (1.4 MHz)

100 RB (20 MHz)

› Support for paired and unpaired spectrum allocations

timeFDD

timeHalf-duplex FDD

(terminal-side only)

timeTDD

10 MHz 15 MHz 20 MHz3 MHz 5 MHz1.4 MHz

with a single radio-access technology economy-of-scale

Supported Frequency Bands20251710

19801785 18801805

2110 2200

2110 2170

26902500

2500 2570 2620 26901710

2300 2400

Generalbands

Regional bands

Local bands

Band 3 Band 1 Band 7

Band 2Band 4

Band 10

Paired Uplink Paired Downlink

Legend:Unpaired

19101850 19901930

15251427

IMT IMT IMTITU: IMTMobile

Band 11 & 21 (Japan) Band 9 (Japan)Band 39 (China)

Band 36Band 35(Band 37)

19101850 19901930

Band 33Band 34

Band 40

Band 38

Band 41

2496 2690

Supported Frequency Bands

Paired Uplink Paired Downlink

Legend:

960698

IMT

General bands

Local bands

824 849 869 894

830 845 885875

880 915 925 960

Band 8

Band 5Band 12 Band 13Band 14

Band 18 &19 (Japan)

ITU:

Band 17

815 860

791 821 832 862

Band 20

Regional bands

Rel-9 Rel-10Rel-8

Basic LTE functionality Enhancements & extensions Further extensionsIMT-Advanced compliant

FDD and TDD supportBandwidth flexibility

ICICMulti-antenna supportdata1data2data3data4

Channel-dependent scheduling Hybrid ARQ

OFDM transmission

MBMS Carrier Aggregation

Relaying

Multi-antenna extensionsDual-layer beamforming

Positioning

LTE – Continuous Evolution

2008 2009 2010

RelayingRel-10

• Repeater– Possible already in Rel-8, simply amplifies and retransmits recevied signal

• Relaying (added in Rel-10)– Relay = small base station connected to RAN using LTE radio resources– Mainly interesting if fibre/microwave backhaul is more expensive than using LTE

spectrum

Relay cell

Donor cell

HetNets• What?

Low power nodes placed throughout a macro-cell layout– Heterogeneous Networks

› “Conventional”–Independent pico cells

›“Relay”–Independent relay cells–Relay connected to macro

›“RRU”–Remote “pico antenna”,processing in macro

–No new pico cells

› Why?High data rates dense infrastructure...but non-uniform user distribution

– Macro for coverage, pico for high data rates› How?

The Wireless Evolution

Additional functionality and capabilities

• Improved performance• New application areas

Everything is connected • 50 billion devices• Need for new business models?

More Reading…

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