UMTS Overview & Air-Interface

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CHAPTER 1 Introduction

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bit of cellular history

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LTE/4G5G ?!?


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Drivers for Mobile Data

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Past Trends & Projections

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Present Trends & Projections

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Third Generation Convergence

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Required Data Rates from 3G

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3 rd Generation Mobile Systems

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UMTS Key Points

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Parameter WCDMA GSM

Carrier Spacing 5 MHz 200 KHz

Frequency Reuse 1 1-18

Power Control 1500 Hz 2 Hz

Quality Control RRM algorithms Frequency Planning

Frequency Diversity Multipath Diversitywith RAKE Rx.

--

Packet Data Load BasedTime Slot based with

GPRS

WCDMA & GSM Comparison

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Migration Strategies

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Further Evolution

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CHAPTER 2 WCDMA Network Architecture

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USIM

ME

Node B

Node B

Node B

Node B

RNC

RNC

MSC/VLR GMSC

SGSN GGSN

HLR

PLMN,PSTN, ISDN,

etc.

Internet

Uu Iu

UE UTRAN CN External Networks

Cu IurIub

PLMN Elements

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BSC

BTS

BTS

BTS

GSM

BSS

Node B

Node B

Node B

Node B

Node B

RNC

RNC

IubRNS

RNS

Iur MSC/VLRGMSC

HLR

Other PLMN

PSTN/ISDN

Circuit Domain

Iu

Iu

Gb

A GGSNSGSN

INTERNET

CorporateNetworks

Packet Domain

IP Network

2G/3G Combined Network Architecture

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3G RAN

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3G RAN

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Conversational

Streaming

Interactive

Background

D e l a y I n s e n s i t i v i t y

UMTS QoS Classes

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Preserved timerelationshipbetweenpackets

Delay intolerant

Voice, videogames etc

Preserved timerelationshipbetweenpackets

Not delay

sensitive

Streamingmulti-media

Preserved

data integrity

Requestresponsepattern

Webbrowsing,networkgames

Destination

not expectingdata withincertain time

Preserve data

integrity

emails

Conversational Streaming Interactive Background

UMTS QoS Classes

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UMTS Bands

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UMTS Bands

UMTS Bands

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LAC / RAC in 3G RAN

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CHAPTER 3 WCDMA Concepts

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CDMA C


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CDMA Concept

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CDMA C


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CDMA Concept

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UMTS C i


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UMTS Carrier

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CDMA C t


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CDMA Concept

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CDMA C t


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CDMA Concept

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SPREADING / De SPREADING Concept


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SPREADING / De-SPREADING Concept

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SPREADING FACTOR & PROCESSING GAIN


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SPREADING FACTOR & PROCESSING GAIN

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Common Measurement Quantities in UMTS


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Signal Level (CPICH RSCP) and Signal Quality (CPICH Ec/No)

The coverage area of the cell are defined by the signal level (RSCP) and signal quality(Ec/No) of the Primary Common Pilot Channel (CPICH).

The Primary Common Pilot Channel Received Signal Code Power, commonly calledRSCP, is simply the received power ( dBm) of the Common Pilot Channel.

The Primary Common Pilot Channel (CPICH) received Energy per Chip (Ec) to Noise(No) ratio, is used to measure the received quality of the Primary Common PilotChannel (CPICH).

Ec/No is the ratio of the received Energy per Chip to the Noise power spectraldensity in the band. In this case, the Chip Energy (Ec ) is the power of the spreaded

Primary Common Pilot Channel (CPICH) at the receiver.

Ec is related to Received Signal Code Power (RSCP) in that both measure the powerof the Primary Common Pilot Channel (CPICH); the only difference being Ec is thepower of the spread signal whereas RSCP is the power measured after de-spreading.


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No (N-not) is the received wide band power, including thermal noise and noisegenerated in the receiver within the receivers bandwidth. It is generally used toidentify the Noise Spectral Density.

The Primary Common Pilot Channel (CPICH) is one of the continuously transmitteddownlink Physical Channels. It is the reference signal used by the UE to make radiorelated decisions for:

Cell Selection, Cell Reselection, Soft (intra-frequency) Handover and Hard (inter-frequency) Handover Inter-RAT Handover ( 3G to GSM, 3G to LTE )

All signal level (RSCP) and quality measurements (Ec/No) are made based upon orrelative to the Primary Common Pilot Channel.

Eb/No is the received energy per Bit (symbol) of the signal over the received wideband power after de-spreading, including thermal noise and noise generated in thereceiver, within the receivers bandwidth. The fundamental difference betweenEb/No and Ec/No is Spreading Factor.

Eb/No therefore equals Ec/No * Spreading Factor.


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Frame Structure in UMTS


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WCDMA Codes


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OVSF Codes : 4 256 (UL) although in HSUPA SF2 is also used now , 4 512 (DL)


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OVSF C d (S di C d )


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OVSF Codes (Spreading Codes)

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OVSF C d (S di C d )


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OVSF Codes (Spreading Codes)

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OVSF C d (UL/DL)


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OVSF Codes (UL/DL)

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WCDMA Codes


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Code Comparison

Does not affect Tx. BandwidthIncreases Tx. BandwidthSpreading

Long 10ms code: Gold CodeOVSFCodeFamily

Uplink= millionsDownlink= 512

No. of codes under one Scrmabling code is equalto the Spreading Factor

Number ofCodes

UL: 10ms=38400 chipsDL:10ms=38400 chips

UL: 4-256 chipsDL: 512 chips

Length

UL:Separation of TerminalsDL: Separation of sectors

UL: Separation of Physical dataDL:Separation od DL connections

Usage

ScramnblingCode

Channelisation CodeProperty

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WCDMA - OSI Model


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UMTS Air Interface Channels (UL/DL)


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Logical Channels


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Logical Channels


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Logical Channels


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Transport Channels


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Transport Channels


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Transport Channels


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Transport Channels


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Physical Channels (DL)


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Physical Channels (UL)


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Channel Mapping


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Channel Mapping (typical configuration)


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Downlink Signal


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Downlink Signal


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Remaining Power for Traffic Channel (DCH)

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Uplink Signal


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UE Power Classes


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CHAPTER 5 UMTS Functionalities

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Rake Receiver


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Rake Receiver


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Handovers (Soft / Softer / Hard)


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Soft Handover


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Compressed Mode


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Compressed Mode (Transmission Gap)


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3G Functionalities


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These functionalities extensively interact with each other81

Admission Control (AC)


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Load Control (LC)


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3G Functionalities (AC / LC in DL)


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3G Functionalities (AC / LC in UL)


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3G Functionalities (AC / LC in UL)


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3G Functionalities (Packet Scheduler)


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3G Functionalities (Packet Scheduler)


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3G Functionalities (Open loop Power Control)


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3G Functionalities (Closed loop Power Control)


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3G Functionalities (Closed loop Power Control)


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UMTS Overview & Air-Interface

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