Evolution of cellular technologies

3G Overview• 3G is created by ITU-T and is called IMT-2000

IMT-2000, “International Mobile Telecommunications”

• Wideband Code Division Multiple Access• CDMA 2000 - Code Division Multiple Access 2000• UMTS - Universal Mobile Telecommunications System• time division duplex- code division multiple access• Time Division Synchronous Code Division Multiple Access• Universal Wireless Communications • Digital Enhanced Cordless Telecommunications

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

HSDPA1-10Mbps

WCDMA2

Mbps

EGPRS473kbps

GPRS171kbps

GSM9.6

kbps

Push-to-talk

Broadbandin wide area

Video sharing Video telephonyReal-time IPmultimedia and gamesMulticasting

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 c.w. GPRSInefficient -> ties up resources, even when nothing sentNot as popular as GPRS (many skipping HSCSD)

EDGE

Enhanced Data Rates for Global Evolutionmprovement in data rate on short distancesCan fall back to GMSK for greater distancesCombine with GPRS (EGPRS) ~ 384 kbpsCan also be combined with HSCSDWCDMA

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

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.

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

Gateway GPRS support node (GGSN)[

• Gateway GPRS support node (GGSN)• The gateway GPRS support node (GGSN) is a main

component of the GPRS network. The GGSN is responsible for the internetworking between the GPRS network and external packet switched networks, like the Internet

• From an external network's point of view, the GGSN is a router to a "sub-network", because the GGSN ‘hides’ the GPRS infrastructure from the external network.

Gateway GPRS support node (GGSN)[

• When the GGSN receives data addressed to a specific user, it checks if the user is active. If it is, the GGSN forwards the data to the SGSN serving the mobile user, but if the mobile user is inactive, the data is discarded. On the other hand, mobile-originated packets are routed to the right network by the GGSN.

• The GGSN is the anchor point that enables the mobility of the user terminal in the GPRS/UMTS networks

Gateway GPRS support node (GGSN)[

• The GGSN converts the GPRS packets coming from the SGSN into the appropriate packet data protocol (PDP) format (e.g., IP or X.25) and sends them out on the corresponding packet data network

Serving GPRS support node (SGSN)

• A serving GPRS support node (SGSN) is responsible for the delivery of data packets from and to the mobile stations within its geographical service area.

• Its tasks include packet routing and transfer, mobility management (attach/detach and location management), authentication and charging functions. The location register of the SGSN stores location information.

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

UTRAN

• Wide band CDMA technology is selected for UTRAN air interface

• 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

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 protocols3.5G introduces many new features that will enhance the UMTS technology in future.

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

Background of LTE

key requirements was defined for the new system • Packet-switched domain optimization • Roundtrip time between server and user equipment (UE) must be

bellow 30ms and access delay below 300 ms • Uplink peak rate 75 Mbps • Downlink peak rate 300Mbps • Improvements to mobility and security • Terminal power efficiency improvements • Capacity increase compared to 3GPP release 6 (HSDPA/HSUPA

Comparison of LTE Speed

HSPA vs LTE

Advantages of LTE

Major LTE Radio Technogies

• Uses Orthogonal Frequency Division Multiplexing (OFDM) for downlink

• Uses Single Carrier Frequency Division Multiple Access (SC-FDMA) for uplink

• Uses Multi-input Multi-output(MIMO) for enhanced throughput

• Reduced power consumption

OFDMA & SC-FDMA

• The LTE air interface uses Orthogonal Frequency Division Multiplexing (OFDM). Also to reach the agreed data levels multiple input / multiple output (MIMO)

• technologies, together with high rate modulation• OFDMA is used in the downlink of LTE but for the uplink

Single Carrier – Frequency Division Multiple Access (SC-FDMA)

• OFDM-based technology was chosen for the following reason – it can achieve the targeted high data rates with simpler

implementations involving relatively low cost and power-efficient hardware

multiple input / multiple output (MIMO)

• To minimize the effects of noise and to increase the spectrum utilization and link reliability LTE uses MIMO technique to send the data. The basic idea of MIMO is to use multiple antennas at receiver end and use multiple transmitters when sending the data

LTE impact on network architecture

• The LTE network architecture is an overall flat architecture

• It consists of an e-Node B and SAE gateway. This network is based on a TCP/IP protocol with higher service levels like voice, video, messaging, etc. built on it.

• Based on this, feasibility studies related to All IP networks (AIPNs) were started in 2004 by the 3GPP

LTE Architecture

LTE vs UMTS• Functional changes compared to the current

UMTS architecture

LTE Release 8 Key Features (1/2)

• High spectral efficiency– OFDM in Downlink– Single Carrier FDMA in Uplink‐

• Very low latency– Short setup time & Short transfer delay– Short hand over latency and interruption time

• Support of variable bandwidth– 1.4, 3, 5, 10, 15 and 20 MHz

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LTE Release 8 Key Features (2/2)

• Compatibility and interworking with earlier 3GPP Releases

• FDD and TDD within a single radio access technology

• Efficient Multicast/Broadcast

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Evolution of LTE-Advanced (4G)

• Advanced Multi-cell Transmission/Reception Techniques

• Enhanced Multi-antenna Transmission Techniques

• Support of Larger Bandwidth in LTE-Advanced

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LTE-Advanced (4G)

• Peak data rates up to 1Gbps are expected from bandwidths of 100MHz. OFDM adds additional sub-carrier to increase bandwidth

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LTE vs. LTE-Advanced

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