3rd Generation Wireless Network

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3rd Generation

Wireless Network


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Outline

IntroductiontoWCDMA

Why WCDMA ?

Evolution from 2G to 3G

WCDMA / UMTS Architecture Air Interface (WCDMA) Radio Access Network (UTRAN) Core Network

Radio Resources Management

Additional Briefs WCDMA V/s CDMA 2000


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Introduction to WCDMA

Wideband Code Division Multiple Access

(WCDMA) is a CDMA Channel that is four

times wider than the current channel that are

typically used in 2G Networks.

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Outline


Why WCDMA ?






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Why WCDMA ?

The significant increase in subscribers and trafficrequires large BW. The answer to the capacity and BW

demand is the provision of new spectrum and the

development of a new technology

Wideband CDMA

(WCDMA)

WCDMA was developed in order to create a global

standard for real time multimedia services that

ensured international roaming.

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Outline


Why WCDMA ?






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Evolution 2G to 3G Revolution

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GSM

CDMA2000

WCDMA

IS95A

IMT2000

IS95B

GPRS

EDGE


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Evolution : From 2G to 3G


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Evolution : From 2G to 3G

Fully specified and world-widely valid,Major interfaces should be standardized and open.

Supports multimedia and all of its components.

Wideband radio access.

Services must be independent from radio accesstechnology and is not limited by the network

infrastructure.

Primary Requirements of a 3G Network


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Standardization of WCDMA

Multiple Access Method DS-CDMADuplexing Method FDD/TDD

Base Station Synchronization Asychronous Operation

Channel Separation 5MHz

Chip Rate 3.84 Mbps

Frame Length 10 ms

Spreading modulation Balanced QPSK (downlink)Dual-channel QPSK(uplink)Complex spreading circuit

Data modulation QPSK (downlink), BPSK (uplink)Coherent detection User dedicated time multiplexed pilot

(downlink and uplink), common pilot inthe downlink

WCDMA Air Interface & Main Parameters


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Outline


Why WCDMA ?






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WCDMA System Architecture

USIM

ME

Node B

Node B

RNC

Node B

Node B

RNC

MSC/VLR

GMSC

SGSN GGSN

HLR

UTRAN CNUE

ExternalNetw

orks

Cu

Uu Iu

IubIur


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WCDMA Air Interface

Wideband CDMA, Overview

DS-CDMA, 5 MHz Carrier Spacing,

CDMA Gives Frequency Reuse Factor = 1

5 MHz Bandwidth allows Multipath Diversity using Rake

Receiver

Variable Spreading Factor (VSF) to offer Bandwidth onDemand (BoD) up to 2MHz

Fast (1.5kHz) Power Control for Optimal InterferenceReduction

Services multiplexing with different QoS Real-time / Best-effort 10% Frame Error Rate to 10-6 Bit Error Rate

UE UTRAN CN


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WCDMA Air Interface UE UTRAN CN

Direct Sequence Spread Spectrum

User 1

User N

Spreading

SpreadingReceived

Dispreading

Narrowband

CodeGain

Frequency Reuse Factor = 1

Wideband

Wideband

f

f

ff

f

f

VSF Allows Bandwidthon Demand. LowerSpreading Factor requiresHigher SNR, causingHigher Interference inexchange.

Variable Spreading Factor (VSF)

User 1

Spreading : 256

Wideband

f f

User 2

Spreading : 16

Widebandf f


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WCDMA Air Interface UE UTRAN CN

Protocol Architecture


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UTRAN UE UTRAN CN

USIM

ME

Node B

Node B

RNC

Node B

Node B

RNC

MSC/VLR

GMSC

SGSN GGSN

HLR

UTRAN CNUE

ExternalNetw

orks

Cu

Uu Iu

IubIur


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UTRAN UE UTRAN CN

Node B

Node BRNC

Node B

Node B

RNC

IubIur

UTRAN

RNS

RNS

Two Distinct Elements :

Base Stations (Node B)Radio Network Controllers (RNC)

1 RNC and 1+ Node Bs are group togetherto form a Radio Network Sub-system (RNS)

Handles all Radio-Related Functionality

Soft Handover

Radio Resources Management Algorithms

UMTS Terrestrial Radio Access Network, Overview


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UTRAN UE UTRAN CN

Protocol Model for UTRAN Terrestrial Interfaces

Application

Protocol

Data

Stream(s)

ALCAP(s)

Transport

Network

Layer

Physical Layer

Signaling

Bearer(s)

Transport

User

Network

Plane

Control Plane User Plane

Transport

User

Network

PlaneTransport Network

Control Plane

RadioNetwork

Layer

Signaling

Bearer(s)

Data

Bearer(s)

Derivatives :

Iur1, Iur2, Iur3, Iur4

Iub

Iu CS

Iu PS

Iu BC

Functions of Node B (Base Station)

Air Interface L1 Processing (Channel Coding, Interleaving, Rate Adaptation,Spreading, etc.)

Basic RRM, e.g. Inner Loop Power Control


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UTRAN UE UTRAN CN

Node B

Node B

RNC

Logical Roles of the RNC

Controlling RNC (CRNC)

Responsible for the load andcongestion control of its own cells

CRNC

Node B

Node B

SRNCServing RNC (SRNC)

Terminates : Iu link of user data,Radio Resource Control Signaling

Performs : L2 processing of datato/from the radio interface, RRMoperations (Handover, Outer LoopPower Control)

Drift RNC (DRNC)

Performs : Macro-diversityCombining and splitting

Node B

Node B

DRNC

Node B

Node B

SRNC

Node B

Node B

DRNC

UE

UE

Iu

Iu

Iu

Iu

Iur

Iur


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Core Network UE UTRAN CN

USIM

ME

Node B

Node B

RNC

Node B

Node B

RNC

MSC/VLR

GMSC

SGSN GGSN

HLR

UTRAN CNUE

ExternalNetw

orks

Cu

Uu Iu

IubIur


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Summary

System Architecture, Bearer Services, QoS Classes

WCDMA Air Interface : Spread Spectrum, Transport Channels

UTRAN : Roles of RNCs and Node Bs

Core Network : Responsible for switching system

USIM

ME

Node B

Node B

RNC

Node B

Node B

RNC

MSC/VLR

GMSC

SGSN GGSN

HLR

UTRAN CNUE

ExternalNetworks

Cu

Uu Iu

IubIur


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Outline


Why WCDMA ?






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Network Based Functions

Admission Control (AC)

Load Control (LC)

Packet Scheduler (PS)

Connection Based Functions

Handover Control (HC)

Power Control (PC)


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Outline


Why WCDMA ?






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WCDMA V/s cdma2000

Some of theMajor Differences

WCDMA cmda2000 Remarks

Spread SpectrumTechnique

5Mhz WidebandDS-SS

Multicarrier,

3x1.25MHzNarrowband DS-SS,250kHz Guard Band

Multicarrier does not requires acontiguous spectral band.

Both scheme can achieve similarperformance

Chip Rates 3.84Mcps 3.6864Mcps (1.2288

per carrier)

Chip Rate alone does not determine

system capacity

Frame Lengths 10ms 20ms for data, 5msfor control

Response and efficiency tradeoff

Power Control Rate 1.5kHz 800Hz Higher gives better link performance

Base StationSynchronization

Asynchronous Synchronized Asynchronous requires not timingreference which is usually hard toacquire.

Synchronized operation usually givesbetter performance


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Conclusion

The concept of a WCDMA adds flexibility in the 3Gdeployments, enhances system performance, andprotects network investments through reuse ofresources.

A WCDMA supports the growth of todays servicesas well as the creation and growth of mobileservices beyond voice, data, video.

In Short, WCDMA is the technology design toprovide service of voice, data and video with thesame handset that customer is using even oninternational roaming.

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Key References

Key References

WCDMA for UMTS Radio Access for Third Generation Mobile Communications, 2nd Ed., Edited by Harri Holma and Antti Toskala

Overview of UMTS Telecommunication Software and Multimedia Laboratory, Helsinki University of Technology

Course S-72.238 : Wideband CDMA systems, Communications Laboratory, Helsinki University of Technology

WCDMA Requirements and Practical Design Rudolf Tanner and Jason Woodard3

GPP, Technical Specification Group RAN, User Equipment (UE) Radio Transmission and Reception (FDD), 3GPP TS 25.101

version 6.11.0, March 2006, available at www.3gpp.org

GSM World www.gsmworld.com


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Thank You

Questions ???

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Documents

3rd Generation Wireless Network