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Pag. 1

Evolutionary trends of mobilevolutionary trends of mobilesystems: from GSM to CRSystems: from GSM to CRSUniversity of Bolognaniversity of Bologna14 January 20114 January 2011

Enrico BuracchiniEnrico BuracchiniTILABTILAB

OutlineOutline GSM & GPRS OverviewGSM & GPRS Overview

UMTS R99 main characteristicsUMTS R99 main characteristics

HSDPA:HSDPA:

-- Rationale,Rationale, main characteristicsmain characteristics and differencesand differences vsvs R99R99

-- R5 UE categoriesR5 UE categories

-- HSPA evolution hintsHSPA evolution hints

SystemsSystemsbeyongbeyong 3G: LTE & LTE3G: LTE & LTE--AA

-- LTE: 3GPP requirements & enabling technologiesLTE: 3GPP requirements & enabling technologies

-- LTELTE--A: 3GPP requirements & additional functionalitiesA: 3GPP requirements & additional functionalities vsvs LTELTE

SDR (Software Defined Radio) & CRS (Cognitive Radio Systems)SDR (Software Defined Radio) & CRS (Cognitive Radio Systems)


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AA wireless mobile systemwireless mobile system

PSTN / ISDNOtherNetworks

IN

MSC (Switching & MM)

Control of

Radio Stations (BSC/RNC)

Radio

Coverage

(BTS,

Node B)

Radio

Access

Web, Internet

ACCESS TECHNIQUES FORACCESS TECHNIQUES FORMOBILE COMMUNICATIONSMOBILE COMMUNICATIONS

P - Power

T - Time

F - Frequency

P

TP

T

F

P

T

F

FDMA (TACS)

TDMA (GSM)

CDMA (UMTS)

F


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Pag. 3

GSM/GPRSGSM/GPRS

GSM FREQUENCIESGSM FREQUENCIES

900 11001000 1200 1300 1400 1500 1600 1700 1800 1900

GSM 900GSM 900 GSM 1800GSM 1800

MHz

890 935915 960

Up Down

1710 1785 1805 1880

Up Down

124124

channelschannels

374374

channelschannels


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BURSTTRANSMITTED

BY

TDMA FRAME(4.6 ms)

MOBILE 1

MOBILE 2

MOBILE 8TIME

TIME-SLOT: 577 s SIGNAL BURST: 543 s

GSM functionsGSM functions

--TDMA access techniqueTDMA access technique

GSM traffic burst structureGSM traffic burst structure

T

3

S

1

S

1

1

3

GP

8.25

Coded Data

57

Training Seq.

26

Coded Data

57

Type

Number of Bits

148 Bit

Stealing flagGuard Time

Tail bits

(guard bits)


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The GSM systemThe GSM system

ArchitectureArchitecture && EquipmentEquipment

MSC Mobile Switching CenterOMC Operations & Maxz intenance CenterSM-SC Short Message Service Center

MS Mobil e Stati onBTS Base Transceiver StationBSC Base Station ControllerBSS Base Station Subsystem

MS BSS

VLR

BTS

PSTN

ISDN

Other Netws

MSCBSC

HLR EIR

OMC

AuC

SM-SC

HLR Home Location RegisterVLR \ C enter EIR Equipment Identi ty Reg is ter

PHASE 1PHASE 1

BasicBasic ServicesServices

Telephony

Emergency calls

Short Message Services (Mobile Terminated & Originated)

Group 3 Fax & CS data @ 9.6 kb/s

Call Forwarding & Barring

PHASE 2PHASE 2

NewNew SupplementarySupplementary ServicesServices

Call Waiting & Call Hold

Line Identification & Multi-Party Call

Closed User Group & Advice of Charge

GSM StandardGSM Standard EvolutionEvolution (I)(I)


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PHASE 2+PHASE 2+ CS & PS DataCS & PS Data ServicesServices

HSCSD (High Speed Circuit Switched Data)

GPRS (General Packed Radio Service)

EDGE (Enhanced Data rate for the GSM Evolution)

SupplementarySupplementary ServicesServices

CCBS (Completion of Call to Busy Subscriber)

USSD (Unstructured Supplementary Service Data)

OtherOther Specific services support (e.g. SIM Toolkit)

Mobile Number Portability

GSM StandardGSM Standard EvolutionEvolution (II)(II)

GeneralGeneral PacketPacket Radio Service (GPRS)Radio Service (GPRS)

External

Data

Network

BSC

BTS

GGSN

MSC

SGSN

VLRHLR

Signalling

Data

RRM

Two (on 4) implemented coding scheme: CS1 & CS2, for a bit rate of 8 kb/s &12kb/s per slot

For a 4 (DL) +1 (UL) terminal, maximum bit rate @ 48kb/s (DL): the effective one isaround 40kb/s

TwoTwo (on 4)(on 4) implementedimplemented codingcoding schemescheme:: CS1 & CS2,CS1 & CS2, forfora bit rate of 8a bit rate of 8 kbkb /s &/s &12kb/s per slot12kb/s per slot

ForFor a 4 (DL) +1 (UL) terminal,a 4 (DL) +1 (UL) terminal, maximummaximum bit rate @ 48kb/s (DL): thebit rate @ 48kb/s (DL): the effectiveeffective oneone isisaroundaround 40kb/s40kb/s

Class A:PS&CS simultaneouslyClass A:PS&CS simultaneousl y

Class B: registration to both PS & CS, but noClass B: registration to both PS & CS, but no

simultaneous usagesimultaneous usage

Class C: registration & usage alternateClass C: registration & usage alternate

GatewayGateway

MobilityMobility managementmanagement

RouteingRouteing

EncapsulationEncapsulation

MobilityMobility managementmanagement

Authentic ationAuthen tic atio n

CipheringCiphering

RouteingRouteing


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New modulation scheme to increase the data rate per slot:New modulation scheme to increase the data rate per slot: 88PSKPSK

Both CS (ECSD) & PS (EGPRS)Both CS (ECSD) & PS (EGPRS)

ECSD:ECSD: up to 32 kb/s x slot & peak rate of 64kb/sup to 32 kb/s x slot & peak rate of 64kb/s

EGPRSEGPRS:: up to 59.2 kb/s per slot & peak rate of 384 kb/sup to 59.2 kb/s per slot & peak rate of 384 kb/s

New terminals (dualNew terminals (dual--mode EDGE/GSM) & new transceiver inmode EDGE/GSM) & new transceiver inBTSsBTSs

EnhancedEnhanced Data rateData rate forfor the GSMthe GSM EvolutionEvolution

(EDGE)(EDGE)

UMTSUMTS

R99R99


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IMTIMT--20002000 IMTIMT--20002000

18851885 2025202519201920 20102010

MSSMSS

19801980 21102110 22002200

MSSMSS

21702170 MHzMHz

ITUITU

IMTIMT--20002000 IMTIMT--20002000

18801880 2025202519001900 20102010

MSSMSS

19801980 21102110 22002200

MSSMSS

21702170 MHzMHz

EUROPEEUROPEEUROPE

DECTDECT

UMTSUMTS corecore bandsbands assignmentassignment

UMTS R99UMTS R99 architecturearchitecture

RNC

RNCNode B

Node B

Node B

Node B

UTRAN

Iucs

Iur

Iub

Access Network Core Network

HLR

BTS

PSTN

ISDN

Packet

Data

Networks3G SGSN GGSN

3G MSC/VLR

Iucs Iups

Iups

Gs

Gn


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FDD (WBFDD (WB--CDMA) techniqueCDMA) technique

P - Power

T - Time

F - Frequency

P

T

F

CDMA (UMTS)

All the users are on the samefrequencies and they aredistinguished by means of acode

TDD (TDTDD (TD--CDMA) techniqueCDMA) technique

Freq

uenc

y

One Time Slot

3.84

Mchip

/s

1 2 3 . . . 14 15

Codes

Energy

Time

frame with

15 time slots

WB-TDMA/CDMA


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UTRA/FDD UTRA/TDD

Access technique WCDMA Hybrid WCDMA+TDMA

Chip rate

Carrier spacing 4.4-5 MHz

3.84 Mcps (SF FDD:4-256, TDD 1-16)

Frame duration 10 ms

N. slot per frame 15

BTS synchronizationNot required Not required

(advisable)

Modulation DL: QPSKUL: Dual-channel QPSK UL: QPSK

Coherent receiver Uplink e downlink

Multi-rate Variabile SF + Mult i-code + Mult i-slot (TDD)

MainMain parametersparameters

DL: QPSK

Soft Handover andSoft Handover and MacrodiversityMacrodiversity(WCDMA)(WCDMA)

node

node

Node

A

Node

B

node

node

RNCRNC--AA

RNCRNC--BB

UTRA

N

RNS

RNS

UE

CN


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MacrodiversityMacrodiversity

circuit 1

circuit 2

Frame selection

Node B 1

Node B 2

RNC UMSC

SoftSoft capacity & cell dynamiccapacity & cell dynamic

C/I 1/N

Cell with radius R and N users

We assume that the user density increase:

Cell with radius R and (N+X) > N users

(C/I) 1/(N+X) < C/IIn the new load situation if we want to stick to

the original C/I target we have to reduce the cell

radius

N

N

N+X


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UMTSUMTS-- HSDPA (R5)HSDPA (R5)

HSDPA positioningHSDPA positioning vsvs other solutionsother solutions

100 m 1000 m 10 km

100 kbit/s

1 Mbit/s

10 Mbit/s

UMTSRelease99

HSDPA(UMTSRelease5)

WLAN (802.11b)

EDGE

GPRS

Velocit diTrasmissione

Raggio diCella

bit rate

cell radius


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HSDPAHSDPA rationalerationale

to improve data speeds per user High speed download (mails, video and mp3)

Video streaming

Highly interactive games

High speed brows ing

to improve service latency

to improve Network Capacity

The HSPA deployment is based on the reuse of 3G network

infrastructure: same NodeB (modified) and RNC

same Core Network

same site/mast/antennas.

3GPP HSDPA3GPP HSDPA Rel.5Rel.5

Introduced in 3GPP Release 5

Main Characteristics vs R99:

Shared packet transmission

Higher order modulation(16QAM)

Shorter TTI (2ms vs 10ms)

Adaptive modulation &coding

Fast Link Adaptation

Fast Hybrid HARQ

Advanced packet schedu ling


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HSDPA: Main characteristicsHSDPA: Main characteristics vsvs UMTS R99UMTS R99

R5 UE categoriesR5 UE categories

UE categories defined on the basis of:

1) Number of codes that can be elaborated per each TTI

2) Maximum bit rate over the entire frame

3) Minimum interval elapsing between two subsequent TTIs4) Possible modulation schemes (only QPSK, or both QPSK and 16-QAM)

5) Storage dimension for the HARQ, e.g the less powerful class does notaccept the Incremental Redundancy at the maximum bit rate.

3GPP TS 25.306


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Pag. 15

1,6

0,8

13,4

9,6

6,7

6,7

3,4

3,4

1,6

1,6

1,1

1,1

Bi t r a t edipicco al livelloRLC [Mbit/s]

1,8

0,9

14

10

7,2

7,2

3,6

3,6

1,8

1,8

1,2

1,2

Bi t r a t edipicco al livellofisico [Mbit/s]

QPSKNo1512

QPSKNo2511

QPSK, 16-QAMNo11510

QPSK, 16-QAMNo1159

QPSK, 16-QAMSi1108

QPSK, 16-QAMNo1107

QPSK, 16-QAMSi156

QPSK, 16-QAMNo155

QPSK, 16-QAMSi254

QPSK, 16-QAMNo253

QPSK, 16-QAMSi352

QPSK, 16-QAMNo351

Modulazionisupportate

IR al maxb i t r a t e

Minimo intervallointer-TTI

Max. Num.Codici

Classe

1,6

0,8

13,4

9,6

6,7

6,7

3,4

3,4

1,6

1,6

1,1

1,1

Bi t r a t edipicco al livelloRLC [Mbit/s]

1,8

0,9

14

10

7,2

7,2

3,6

3,6

1,8

1,8

1,2

1,2

Bi t r a t edipicco al livellofisico [Mbit/s]

QPSKNo1512

QPSKNo2511

QPSK, 16-QAMNo11510

QPSK, 16-QAMNo1159

QPSK, 16-QAMSi1108

QPSK, 16-QAMNo1107

QPSK, 16-QAMSi156

QPSK, 16-QAMNo155

QPSK, 16-QAMSi254

QPSK, 16-QAMNo253

QPSK, 16-QAMSi352

QPSK, 16-QAMNo351

Modulazionisupportate

IR al maxb i t r a t e

Minimo intervallointer-TTI

Max. Num.Codici

Classe

R5 UE categories and related bit ratesR5 UE categories and related bit ratesclass

maxcodes #

minimum TTIinterval

peak bit rateat layer 1

(mbps)

peak bit rateat RLC level

(mbps)

IR at peak

bit rate

supportedmodulation

Yes

Yes

Yes

Yes

3GPP TS 25.306

HSPA Evolution hintsHSPA Evolution hints

HSPA Evolution 710 Ericsson White Paper:

www.3g4g.co.uk/Hspa/HSPAE_WP_0710_Ericsson.pdf


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Systems beyond 3G:Systems beyond 3G:

LTE & LTELTE & LTE--AA

3GPP Requirements of LTE3GPP Requirements of LTE


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LTE: key enabling technologiesLTE: key enabling technologies

x1

x2

x3

y1

y2

y3

MIMOMIMO Network EvolutionNetwork Evolution

eNB eNB

eNB

MME/UPE MME/UPE

S1

X2

X2

X2

EvolvedPacketCore

E-UTRAN

OFDMOFDMScalable BandwidthScalable Bandwidth

OFDM: OrthogonalOFDM: Orthogonal FrequencyFrequency Division ModulationDivision Modulation

OFDM as modulation Spectrum is divided in several orthogonal sub-carriers : f=1/f=1/TsTs

Information flow is divided over the sub-carriers

Mo-demodulation by FFT/iFFT

OFDM as mulitple access (OFDMA) A group of sub-carr iers can be al located to d if ferent users inside the avai lab le

bandwidth

ffsingle-carrier mod.

fconventional multi-carrier modulation

OFDM


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OFDM:OFDM: CharacteristicsCharacteristics

Sub-carriers

FFT

Time

Symbols

N subcarriers in W

Bandwidth

Guard Intervals

Frequency

f=1/f=1/TsTs

High resistance to multipath propagation

Low implementation complexity (IFFT/FFT)

Sharp power spectrum decrease at the band edges

Inter-Symbol Interference (ISI) is eliminated at the receiver by removing the cyclic prefix (i.e.

no need for channel equalizers or Rake receivers) Space-time processing operations performed independently for each sub-carrier (lower

receiver complexity that single carrier transmission)

High Peak to Average Power Ratio (PAPR)

Power amplifiers with high linearity are required (critical issue on the terminal side)

Sensitivity to frequency offset and phase noise

Advantages

Disadvantages

OFDM:OFDM: prospros && conscons


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Pag. 19

In 3GPP Long Term Evolution:

Orthogonal Frequency Division Multiple Access (OFDMA) is to be used indownlink direction

Single Carrier Frequency Division Multi ple Access (SC-FDMA) is to be used in theuplink direction

OFDM in 3GPP Long Term EvolutionOFDM in 3GPP Long Term Evolution

DownlinkDownlink Multiple access is achieved in OFDMAOFDMA by assigning subsets of subcarriers toindividual users. The subcarrier spacing in the OFDM downlink is 15 kHz and there

is a maximum of 2048 subcarriers available. The transmission is di vided in time int o

time slots of du ration 0.5 ms and subframes of duration 1.0 ms. A radio frame is 10

ms long. Support ed modulation formats o n the downlink data channels are QPSK,

16QAM and 64QAM.

UplinkUplink SCSC--FDMAFDMA was chosen in order to reduce Peak to Average RatioPeak to A verage Ratio (PAR), which hasbeen identified as a critical issue for use of OFDMA in the uplink where power

efficient user-terminal amplifiers are required. Another impor tant requirement was to

maximize the coverage. For each time interval, the base station scheduler assigns a

unique time-frequency interval to a terminal for the transmissio n of user data,

thereby ensuring intra-cell orthogonality.

EE--UTRANUTRAN architecturearchitecture The E-UTRAN consists of eNBs, providing the E-UTRA user plane

(PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards theUE.

The eNBs are interconnected with each other by means of the X2 interface.

The eNBs are also connected by means of the S1 interface to the EPC (EvolvedPacket Core), more specifically to the MME (Mobility Management Entity) by meansof the S1-MME and to the Serving Gateway (S-GW) by means of the S1-U.

eNB

MME / S-GW MME / S-GW

eNB

eNB

S1

S1

S1

S1

X2

X2X2

E-UTRAN


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Data plane :


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.and what else?.and what else?

SDR & CRSSDR & CRS

Software Defined RadioSoftware Defined Radio

USERUSER

Multiple Needs & Locations

Multiple Environments

Multiple Radio Interfaces

Core Network Interworking

Emergingmerging technologyechnology foror flexiblelexible radioadio systemsystems,multiulti-serviceervice, multiulti-standardtandard, multiulti-bandand,reconfigurable andeconfigurable and reprogrammableeprogrammable byy softwareoftware


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Software radioSoftware radio transceivertransceiver

IDEAL SOFTWAREIDEAL SOFTWARE

RADIO RECEIVERRADIO RECEIVER::

DIGITAL RADIO RECEIVERDIGITAL RADIO RECEIVER

TechnicalTechnical issuesissues forfor a SW radioa SW radio transceivertransceiver

Swradio features

Technical issues

Flexibility

Adaptabil i ty

Mult imode /

Multiband/

Multistandard

Adaptive

Signal

Processing

Wideband RF

Wideband/ hign speed/ highreso lu t ion A/ D D/ A conver ter

High performance s ignal

processing devices

( DSPs, FPGAs, uPs)

Software


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Pag. 23

Cognitive RadiosCognitive RadiosCognitive Radio definit ions:

First defined by Mitola as the point in which wireless personal digitalassistants (PDAs) and the related networks are sufficiently computationallyintelligent about radio resources and related computer-to-computercommunications to: (a) detect user communications needs as a function of usecontext, and (b) to provide radio resources and wireless services mostappropriate to those needs.

The FCC suggests: A Cognitive Radio (CR) is a radio that can change itstransmitter parameters based on interaction with the environment in which itoperates. The majority of cognitive radios will probably be Software DefinedRadios (SDRs), but neither having software nor being field programmable arerequirements of a cognitive radio.

CognitiveCognitive RadiosRadios

Cognitive Radio System definition by ITU R Wp1B:

Cognitive Radio System (CRS): A radio system employing technology thatallows the system: to obtain knowledge of its operational and geographicalenvironment, established policies and its internal state; to dynamically and

autonomously adjust its operational parameters and protocols according to itsobtained knowledge in order to achieve predefined objectives; and to learn fromthe results obtained.

[ITU-Report SM.2152 Definitions of Software Defined Radio (SDR) andCognitive Radio System (CRS)]


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Pag. 24

TheThe

CognitionCognition

CycleCycle

A cognit ive radio cont inual ly observes the environment , or ients itself, createsplans, decides, and then acts (Mitola) :

Cognitive Cycle

Cognitive radio systemsCognitive radio systemsApplication/User

Specification Language

Cognition Layer

Configurable Network Elements

Network API

Network StatusSensors

Over the TOP

Cognitive Process

Software ConfigurableEquipment

Cognitive Framework

Applications for cognitive nodes

Advanced Antenna Systems

Multi-RAT ResourceManagement

Management of multiple connections

Cognition enablers, e.g. CPC (Cognitive Pilot Channel)

DYNAMICALDYNAMICAL resource adaptations on the basis of:

Radio conditionsRadio conditions

Traffic conditionsTraffic conditions

User contextUser context


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ImpactsImpacts of SDR/CRof SDR/CR

SimultaneousSimultaneous implementationimplementation of moreof more standardsstandards on theon the samesame BS:BS:

possiblepossible reductionreduction ofof investmentsinvestments,, coveragecoverage flexibleflexible upgrade and futureupgrade and future

adaptabilityadaptability toto traffictrafficvariationsvariations

FOR NETWORK OPERATORS:FOR NETWORK OPERATORS:

FOR MANUFACTURERS:FOR MANUFACTURERS:

Reduced set of HW platforms development for each radio system and for each

market

cost reduction, reduced inventory, scale economy

possibility to correct and improve SW in successive phases

FOR COSTUMERS:FOR COSTUMERS:

Better fruition of existing/new services depending on the context

OpenOpen issuesissues

R&DR&D effortsefforts stillstill necessarynecessary andand ongoingongoing ((maturitymaturity of technologyof technologyandand reliabilityreliability ofof relatedrelated algorithmsalgorithms//methodologiesmethodologies, impact on network, impact on network

management and planningmanagement and planning processesprocesses,, .).)

Dawning ofDawning of standardisationstandardisation & regulation& regulation


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