Considerations for SDR Implementations in Commercial · PDF file1 © 2005 Nokia SDR ETSI...

1 © 2005 Nokia SDR ETSI Nokia.ppt / 08.02.2007 / HOS

Considerations for SDR Implementations in Commercial Radio Networks

Hans-Otto ScheckNokia NetworksP.O.Box 301 FIN-00045 Nokia [email protected]

ETSI Software Defined Radio (SDR) / Cognitive Radio (CR) WorkshopFriday 9th February 2007 - Sophia-Antipolis, France


End to end reconfigurability – E²R Vision


Why Software Defined Radio?

• UMTS – the “Universal Mobile Telecom Standard” isn’t the all universal solution• Even if there would be an universal standard it would not necessarily be the

single dominating standard

• To have a standard, open and flexible architecture for a wide range of communication products - life cycle cost reductions.

• Enhanced wireless roaming by extending the capabilities of current and emerging commercial air-interface standards.

• Over-the-air download of new features and services as well as S/W patches.

• Joint Tactical Radio – DoD initiative:Unified communication across commercial, civil, federal and military organizations.


The SDR BTS and its components

• The RF Block: “Software Defined RF”• From antenna to digital interface (OBSAI & CPRI)• Analog & digital signal processing• Frequency specific components

• The BaseBand Block: “Software Defined BB”• From digital interface (OBSAI, CPRI) to digital interface (transport)• Pure digital signal processing• Frequency independent

• The Transport Block: “End to end service”• Cellular specific networks (E1/T1 transmission, RNC, …)• IP networks


The SDR for commercial and consumer radio networks• Cellular industry: Growing number of incompatible radio technologies

Call for “technology agnostic” spectrum allocation• Consumer industry: Growing number of different applications. From low

rate RFID to high speed WLAN

• Fundamental difference between wide area and local area systems:

Wide Area• Spectral efficiency and cell planning• Coordinated spectrum usage

(minimize interference by design)• High performance RF

(TX power, RX sensitivity & blocking)Is SDR and cognitive radio feasible?

Local Area• No cell planning• Uncoordinated spectrum usage• Short term spectrum allocation• BTS (WLAN) listens before transmit• Low performance TRXSDR and cognitive radio essential


BTS Throughput vs. Interference

Node-BAvg. SINR ->

avg. cell throughput

Min. throughputat the cell edge

UL traffic on DPCH

• There is no “tolerable” interference level!• Low interference affects the BTS similar like increased noise• Every minute amount of interference reduces the capacity of a

system. The effect might be tolerable in the beginning, but increases gradually with usage of the interfering system

• Gradually decreasing capacity is difficult to detect • Will be compensated with TX power and/or additional sites• Increases gradually both CAPEX and OPEX• With fatal effects on the competitiveness of the network

Clean spectrum is an essential asset!


HW limits the capacity• Radio

• “Radiotelegraphy”: Transmission of news by radiation of electromagnetic waves. • C = W log2(1 + S/N) (Shannon) E = mc2 (Einstein)

• Software• Immaterial ware, non-apparative (m=0) functional parts of an installation.

• The downlink power (PA) is shared between the users • GSM: # of timeslots per carrier, # of carriers per TRX• WCDMA: Service (BW) used by each user, noise (interference, network load)

• Cell breathing is a SDR feature!

0%

20%

40%

60%

80%

100%

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Traffic load factor

Relative cell size

Increased load 800 kbps⇒ Decreased coverage

Low load 200 kbps⇒ Large coverage

128 kbps

64 kbps

8 kbps

128 kbps

64 kbps

8 kbps 144 kbps64 kbps

64 kbps

144 kbps

144 kbps

64 kbps64 kbps

144 kbps64 kbps

64 kbps

144 kbps

144 kbps

64 kbps64 kbps

• Traffic load has direct effect on the cell size

• Radio Resource Management provides means to control cell breathing in network optimisation


Spectrum Usage

1500 1600 1700 1800 1900 2000 2100 2200

WCDMAGSM1800Power(W)

GSM19001

Frequency(MHz)

WCDMADL

WCDMAUL

GSM1800UL

GSM1900UL

GSM 1900DL

GSM 1800DL

RX filter to protect theGSM1800 RX from it’s TX

RX filter to protect theGSM1900 RX from it’s TX

10-15

A wideband RF filter would leave the vulnerable RX LNAs unprotected from the high TX power!

GPS

WCDMA RX filter

GPS RX filter

11 -04© HOS


Why do we need RF Antenna Filters?

Commonly agreed radio rulesWithin GSM band

“Violent”, non-standardcompliant transmitters

100kHz GSM band 12GHz

Power(dBm)

Frequency

0

-10

-20

-30

-40

RX filter

GSM blocking spec.

Wanted channel

>25dB of additionalblocking robustness

12 -04© HOSIntermodulation


Noise in the TX

Modulator&

Digital filter

Modulator&

Digital filterD/AD/A Up-conversion

to RF

Up-conversionto RF PAPA Antenna

filter

Antennafilter

RFfilter

RFfilter

Noise floor: -165dBm/Hz -155dBm/Hz -115dBm/Hz -100dBm/HzPower: -10dBm 30dBm 43dBm

Noise(dBm/Hz) RF & antenna filter

Frequency

PA noise floor-100

-173

TX band RX band

RX noise floor


RF filters in wireless local area systems

-130dBm/Hz-145dBm/Hz

Noise(dBm/Hz)

-100PA noise floor

-173

TX band RX band

RX noise floor

RF & antenna filter

Wide Area Radio Local Area Radio

Reduced TX power

(20W to 20mW)

Reduced RX sensitivity

(<3dB to ~40dB)


Filter technology

Multimode ceramicresonator

Conductor loaded ceramic resonator

Resonator Q / Filter size@ 2GHz

100000

10000

1000

100

Coaxial duplex filterIL < 0.5dBAtt. >70dBPmax ~100W

1l

1ml

1µl

Pictures not in scale!

BAW filterIL = 3 dBAtt.= 25dBPmax ~2W

1.5l

Local area RF filterLocal area RF filter (<75µl)

Wide area RF filter (1.5l)


Cellular Standard Development

1992 2002 20101992 2002 2010

3G Radio

EDGE

Rel.4

Rel.6

HSDPA

Rel.7

Rel.5

03 -06© HOS

Rel.99

1G Radio 2G Radio

Analog CellularGSM P1

GPRSGSM P2

• Three radio generations • Over ten S/W releases within 30 years of cellular development

• Three radio generations • Over ten S/W releases within 30 years of cellular development

Frequency Hopping

VariableData Rates

Multi-Standard

WB channel equalization,

MIMOHSUPA

Variablemodulation

Com

plex

it y LTE

Voice VoiceData


Signal processing flexibility has its price

Flexibility

Power consumption(mW/MOPS)

Dedicatedlogic

Dedicatedlogic

µ Processorµ Processor

Memory

µ Processorµ Processor

Memory

µ Processor

Memory

Addr.MAC

µ Processor

Memory

Addr.MAC

0% (H/W) 100% (S/W)

0.01

0.1

1

10

ASIC

0.001

CPUFPGA

µProcessor

Memory

SatelliteProcessor

SatelliteProcessor

SatelliteProcessor

µProcessor

Memory

SatelliteProcessor

SatelliteProcessor

SatelliteProcessor

DSP

10 -06© HOS

Maximize flexibility

Minimize size & H/W cost


Conclusions

1. SDR is already implemented in existing cellular systems.2. Cellular networks provides us with a country / continent wide coverage and

uninterrupted services.3. Local area and peer to peer radio networks provide high speed in-building

coverage. 4. RF requirements for wide area and local area networks are not compatible

• Wide area: clean spectrum, network planning, high performance RF• Local area: ad-hoc spectrum usage, cognitive radio, low cost RF

5. End to end services require a seamless handover between different radio access networks

Considerations for SDR Implementations in Commercial · PDF file1 © 2005 Nokia SDR ETSI...

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