wireless data communication networks lecture 21: gsm evolution
DESCRIPTION
Wireless Data Communication Networks Lecture 21: GSM evolution. Outline. Evolution of GSM into a packet data network. GSM Evolution path . GSM – migrates towards packet data networks with broadband access air interface. Driver behind the migration – change in the use model for GSM networks. - PowerPoint PPT PresentationTRANSCRIPT
ECE DepartmentFlorida Institute of Technology
Wireless Data Communication Networks
Lecture 21: GSM evolution
ECE DepartmentFlorida Institute of Technology
Outline
Evolution of GSM into a packet data network
Page 2
ECE DepartmentFlorida Institute of Technology
GSM Evolution path
Page 3
GSM – migrates towards packet data networks with broadband access air interface
Driver behind the migration – change in the use model for GSM networks
ECE DepartmentFlorida Institute of Technology
Cellular data networks – throughput comparison
Page 4
ECE DepartmentFlorida Institute of Technology
GPRS Network Architecture
Page 5
ForeignPLMNBG
M S
BSC
DATA-BASESUBSYSTEM
Other SGSN BG
VLR H LRG R
EXTERNALNETW ORKS
BTS
BTS
GSMRADIOSUBSYSTEM
GPRSSUBSYSTEM
PDNGGSNSGSNPCU
AirInterface
GbInterface
GnInterface
GnInterface
GpInterface
GiInterface
GcInterface
GrInterface
GsInterface
AbisInterface
BTS - Base Transceiver StationBSC - Base Station ControllerPCU - Packet Control UnitSGSN - Service GPRS Support NodeGGSN - Gatew ay GPRS Support NodeBG - Border GatewayHLR - HomeLocation RegisterVLR - Visitor Location RegisterGR - GPRS RegisterPDN- Packet Data Netw ork
GPRS introduces new entities to support data packet transmissions New entities are PCU, GSN, Border Gateway, and GPRS register
ECE DepartmentFlorida Institute of Technology
GSM/GPRS – put together
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GMSC
M S
ForeignPLMNBG
BSC
BSC
Other MSC
DATA-BASESUBSYSTEM
Other SGSN BG
V LR H LRG R
EXTERNALNETW ORKS
BTS
BTS
BTS
GSMRADIOSUBSYSTEM
GSMSW ITCHINGSUBSYSTEM
GPRSSUBSYSTEM
PDN
ISDN
MSCTRAU
GGSNSGSNPCU
AirInterface
AbisInterface
GbInterface
GnInterface
GnInterface
GpInterface
GiInterface
GcInterface
GrInterface
GsInterface
AInterface
BInterface
CInterface
EInterface
DInterface
AbisInterface
AirInterface
PSTNBTS
MS
ECE DepartmentFlorida Institute of Technology
GPRS/EDGE – MCS and throughputs
Page 7
GPRS and EDGE introduce multiple Modulation and Coding Schemes (MCS)
MCS allows different data rates through the GSM time slot
Selection of MCS depends on channel condition and capability of mobile
GPRS and EDGE allow for multiple slot aggregation Slot aggregation allows increase in data rate offered to
the user EDGE introduces new modulation scheme – 8-PSK
GPRS MCS
EDGE MCSNote: EDGE supports both GMSK and 8-
PSK
PHY throughput for different MCS
ECE DepartmentFlorida Institute of Technology
UMTS architecture
Page 8Page 8
Node B
Node B
Node B
Node B
R ad ioN etw ork
Contro lle rR N C
U ser E qu ipm ent(U E )
U serS ubscriber
Iden tityM odu le(U S IM )
M obileE quipm ent
(M E )Cu
U M T S Terrestia l R ad io(U TR A N )
R ad ioN etw ork
Contro lle rR N C
M S C /V LR
G M S C /V LR
S G S N
H LR
G G S N
Core N etw ork(C N )
C ircuitSw itchedN e twork
Packet D ataN e twork
Uu Iu
IubIur
Acronyms:
Node B = Base Station
SGSN = Service GPRS Node
GGSN = Gateway GPRS Node
MSC = Mobile Switching Center
VLR = Visitor Location Registry
HLR = Home Location Registry
Open Interfaces:
Uu – W-CDMA air interface
Iub – Node B to RNC
Iur – between RNC
Iu – between UTRAN and CN
W-CDMA air interface for UMTS radio Access
Air interface is based on CDMA access
Reuse of the existing GSM network architecture
Iub fully standardized The core network allows
both GSM and UMTS radio access
ECE DepartmentFlorida Institute of Technology
UMTS Radio Interface
Page 9Page 9
• Air interface determines the performance of a cellular system
• W-CDMA – revolutionary change from GSM’s TDMA scheme
• Advanced radio resource management – required by diverse 3G applications
• Multi-rate spreading • W-CDMA is interference limited
• Provides soft capacity and• Coverage, capacity, quality tradeoffs
DL TX Diversity, DL and UL RAKE receiver reception, UL space diversityDiversity support
Coherent on both UL and DLDetection
Open loop and closed loop with 1500 commands/secPower control
10msFrame Length
15,30,60,120,240,480, 960, 1920 kb/sec
Up to 3 code aggregations
Single code user rates
DL(after coding)
15,30,60,120,240,480, 960 kb/sec
Up to 6 code aggregation
Single code user rates
UL (after coding)
Variable: UL 1-512 (power of 2), DL(1-256)Spreading
3.84 Mc/secondChip rate
5MHzBandwidth
DS-CDMA with FDD and asynchronous operationAccess scheme
ValueProperty
Summary of W-CDMA properties
UL – Uplink, DL - Downlink
10 ms 10 ms 10 ms
Power spectrumdensity
frequency
time
f1
f2
frame
W-CDMAChannel
W-CDMA Scheme
ECE DepartmentFlorida Institute of Technology
Long Term Evolution (LTE) LTE – 4 G technology Changes in both radio access and core Radio access is OFDM based (1.4-20MHz) Core is packet only; Voice as VoIP Simplified core – all IP eNodeB responsible for RRM
Page 10
ECE DepartmentFlorida Institute of Technology
Review
List successor technologies to GSM How is voice handled in GSM (as CS
or as PS) Which technology promises higher
data rates: EDGE or HSPA? What type of access scheme is used
in UMTS? What type of access scheme is used
in LTE? Does LTE core network contain
switches? How is voice handled in LTE? Explain the concept of adaptive MCS
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