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1 3G and beyond
2
Introduction GPRS improves GSM in a number of ways:
Increases data communication speed Increases interoperability with packet switched
data networks, e.g. internet. Allows billing by data transaction rather than
billing by connection time However, GPRS itself still has some issues:
Still quite slow, especially for multimedia and other high bandwidth transmission situations
Speech quality Inconsistent user interface across different
networks
3
UMTS vs GPRS UMTS: Addition of a new radio access network
(RAN) UTRAN: UMTS Terrestrial radio access network UTRAN and GSM RAN can coexist and connect to the
same core network UMTS: The CS-domain may be based on packet
based transport Evolution towards all IP Some day the CS-domain may be abandoned
Introduction of IMS (in Rel-5) IP Multimedia subsystem Supports IP based multimedia services IMS vital for locating IP address of addresses
4
Service RoadmapImproved performance, decreasing cost of delivery
Typical average bit rates (peak rates higher)
WEB browsingCorporate data accessStreaming audio/video
Voice & SMS Presence/location
xHTML browsingApplication downloadingE-mail
MMS picture / video
Multitasking
3G-specific services take advantage of higher bandwidth
and/or real-time QoS
3G-specific services take advantage of higher bandwidth
and/or real-time QoS
A number of mobile services are bearer
independent in nature
A number of mobile services are bearer
independent in nature
HSDPA1-10
Mbps
WCDMA2
Mbps
EGPRS473
kbps
GPRS171
kbps
GSM9.6
kbps
Push-to-talk
Broadbandin wide area
Video sharing Video telephonyReal-time IPmultimedia and gamesMulticasting
CD
MA
200
0-E
VD
O
CD
MA
200
0-E
VD
V
CD
MA
200
0 1
x
5
GSM Evolution to 3G
GSM9.6kbps (one timeslot)GSM DataAlso called CSD
GSM
General Packet Radio ServicesData rates up to ~ 115 kbpsMax: 8 timeslots used as any one timePacket switched; resources not tied up all the timeContention based. Efficient, but variable delaysGSM / GPRS core network re-used by WCDMA (3G)
GPRS
HSCSD
High Speed Circuit Switched DataDedicate up to 4 timeslots for data connection ~ 50 kbpsGood for real-time applications compare with GPRSInefficient -> ties up resources, even when nothing sentNot as popular as GPRS (many skipping HSCSD)
EDGE
Enhanced Data Rates for Global EvolutionUses 8PSK modulation3x improvement in data rate on short distancesCan fall back to GMSK for greater distancesCombine with GPRS (EGPRS) ~ 384 kbpsCan also be combined with HSCSDWCDMA
6
UMTS
Universal Mobile Telecommunications System (UMTS)
UMTS is an upgrade from GSM via GPRS or EDGE The standardization work for UMTS is carried out
by Third Generation Partnership Project (3GPP) Data rates of UMTS are:
144 kbps for rural 384 kbps for urban outdoor 2048 kbps for indoor and low range outdoor
Virtual Home Environment (VHE) users are consistently presented with the same
personalised features, User Interface capabilities and services in whatever network and whatever terminal, where ever the user may be located
7
UMTS Frequency Spectrum
UMTS Band 1900-2025 MHz and 2110-2200 MHz for 3G
transmission In the US, 1710–1755 MHz and 2110–
2155 MHz will be used instead, as the 1900 MHz band was already used.
8
UMTS Architecture
SD
Mobile Station
MSC/VLR
Base StationSubsystem
GMSC
Network Subsystem
AUCEIR HLR
Other Networks
Note: Interfaces have been omitted for clarity purposes.
GGSNSGSN
BTS BSC
NodeB
RNC
RNS
UTRAN
SIM ME
USIMME
+
PSTN
PLMN
Internet
9
UMTS Network Architecture
UMTS network architecture consists of three domains Core Network (CN): Provide switching,
routing and transit for user traffic UMTS Terrestrial Radio Access Network
(UTRAN): Provides the air interface access method for user equipment.
User Equipment (UE): Terminals work as air interface counterpart for base stations. The various identities are: IMSI, TMSI, P-TMSI, TLLI, MSISDN, IMEI, IMEISV
10
UTRAN Wide band CDMA technology is selected for
UTRAN air interface WCDMA TD-SCDMA
Base stations are referred to as Node-B and control equipment for Node-B is called as Radio Network Controller (RNC). Functions of Node-B are
Air Interface Tx/Rx Modulation/Demodulation
Functions of RNC are: Radio Resource Control Channel Allocation Power Control Settings Handover Control Ciphering Segmentation and reassembly
11
3.5G (HSPA)
High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing WCDMA protocols 3.5G introduces many new features that will enhance the UMTS technology in future. 1xEV-DV already supports most of the features that will be provided in 3.5G. These include:
Adaptive Modulation and Coding Fast Scheduling Backward compatibility with 3G Enhanced Air Interface
12
4G (LTE)
LTE stands for Long Term Evolution Next Generation mobile broadband
technology Promises data transfer rates of 100 Mbps Based on UMTS 3G technology Optimized for All-IP traffic
Lte benefits in a nutshell
Higher Speeds Low latency Faster downloads Simpler networks
Greater End-User Experience
More capacity New services Differentiation
14
Advantages of LTE
15
Comparison of LTE Speed
3GPP LTE Performance Targets
High data rates Downlink: >100 Mbps Uplink: >50 Mbps
Low delay/latency User plane RTT: <10 ms Channel set-up: <100 ms
Cost-effective migration
Key LTE radio access features
TX TX
Advanced antenna solutionsDiversityBeam-formingMulti-layer transmission (MIMO)
20 MHz1.4 MHz
Spectrum flexibilityFlexible bandwidthNew and existing bandsDuplex flexibility: FDD and TDD
SC-FDMA
OFDMALTE radio accessDownlink: OFDMUplink: SC-FDMA
18
Motivation Need for higher data rates and greater spectral efficiency
Can be achieved with HSDPA/HSUPAand/or new air interface defined by 3GPP LTE
Need for Packet Switched optimized system Evolve UMTS towards packet only system
Need for high quality of servicesUse of licensed frequencies to guarantee quality
of servicesAlways-on experience (reduce control plane
latency significantly)Reduce round trip delay
Need for cheaper infrastructureSimplify architecture, reduce number of network
elements
19
LTE performance requirements
Data Rate: Instantaneous downlink peak data rate of 100Mbit/s in a 20MHz downlink spectrum (i.e. 5 bit/s/Hz) Instantaneous uplink peak data rate of 50Mbit/s in a 20MHz uplink spectrum (i.e. 2.5 bit/s/Hz)
Cell range 5 km - optimal size 30km sizes with reasonable performance up to 100 km cell sizes supported with acceptable performance
Cell capacity
up to 200 active users per cell(5 MHz) (i.e., 200 active data clients)
20
LTE performance requirements
Mobility Optimized for low mobility(0-15km/h) but supports high speed
Latency user plane < 5mscontrol plane < 50 ms
Improved spectrum efficiency Cost-effective migration from Release 6 Universal Terrestrial Radio Access (UTRA) radio interface and architecture Improved broadcasting IP-optimized Scalable bandwidth of 20MHz, 15MHz, 10MHz, 5MHz and <5MHz Co-existence with legacy standards (users can transparently start a call or transfer of data in an area using an LTE standard, and, when there is no coverage, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS)
21
Key Features of LTE
Multiple access scheme Downlink: OFDMA Uplink: Single Carrier FDMA (SC-FDMA)
Adaptive modulation and coding DL modulations: QPSK, 16QAM, and 64QAM UL modulations: QPSK and 16QAM Rel-6 Turbo code: Coding rate of 1/3, two 8-state constituent
encoders, and a contention- free internal interleaver. Bandwidth scalability for efficient operation in
differently sized allocated spectrum bands Possible support for operating as single frequency
network (SFN) to support MBMS
22
Key Features of LTE(contd.)
Multiple Antenna (MIMO) technology for enhanced data rate and performance.
ARQ within RLC sublayer and Hybrid ARQ within MAC sublayer.
Power control and link adaptation Implicit support for interference coordination Support for both FDD and TDD Channel dependent scheduling & link adaptation for
enhanced performance. Reduced radio-access-network nodes to reduce
cost,protocol-related processing time & call set-up time
23
LTE Architecture
24
LTE vs UMTS Functional changes compared to the
current UMTS architecture