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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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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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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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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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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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Thanks for your kind attentionThanks for your kind attention
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