3G Training Print Day2 7th June 2011

8/3/2019 3G Training Print Day2 7th June 2011

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UMTS Technology and comparison with GSM 2G and 2.5G Evolution to UMTS

UMTS Standards & Specifications

Evolution of data services

3G Services and Applications Circuit Switched Services

Packet Switched Services

Message Services

Network Architecture, Interfaces & Signaling protocols of UMTS Network Architecture of UMTS

Network elements used within RAN

Main functions of RNC, Core, IN

IMS Concept

Signaling Protocols of UMTS

Recap


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Agenda1. ..

2. .

a) .b) .

UTRAN functionality and working principle WCDMA Basics

Power, FDD, TDD and Cell Characteristics

Scrambling code and channelization code concept.

Structure of UMTS air interface, Modulation, Transport,

Physical and Logical channels

Radio Resource management

HSDPA and HSUPA concepts

Traffic Management in UMTS Databases used in UMTS Network

Subscriber addressing information

Identities related to subscriber in UMTS

Procedures used to maintain mobility management in the Network. Procedures done when mobile gains access to the network

Transport technologies in UMTS

Concepts of PDH

Concepts of SDH

IP and ATM Basics

Agenda


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UMTS Functionality & Working Principle


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WCDMA Basics


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Radio Path Basics: FDMA

The first generation of the mobilesystems used the Frequency DivisionMultiple Access (FDMA) technique.

The radio spectrum is divided into afixed number of channels on differentfrequencies and of a fixed bandwidth

UMTS Radio Path Fundamentals


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Radio Path Basics: TDMA

As systems evolved from analogue todigital, the same frequency could beshared by many users.

This lead to the evolution of 2G

mobile systems that used the TimeDivision Multiple Access (TDMA)technique.

In a TDMA mobile system, eachchannel at a particular frequency isdivided into timeslots.

As a result, multiple subscribers canuse the same frequency tocommunicate.



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Radio Path Basics: CDMA

CDMA functions are much like ourparty.

The CEO hosting the party is ourBase Station (BS) and the guests arethe Mobile Stations (MS).

The different languages correspondto codes in a CDMA system.

The BS can tell the mobiles apart,even though they are transmitting atthe same time, by the codes that theyuse.



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CDMA Technique

The number of subscribers who sharethe same frequency are limited by:

the number of codes and

the amount of interference in theregion of coverage called a cell.

The subscriber may use variable bitrates to transfer data.

Subscribers need more frequency totransfer data.



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The following two techniquescan be used for CDMAsequencing:

1. Frequency Hopping (FH)Sequencing In this technique theinformation to be transmitted is located

in different parts of the frequency bandas a function of time, according to acertain hopping sequence.

2. Direct Sequencing (DS) - In case

of DS, the information to be transferredis spread all over the defined frequencyband as a function of time, and itappears similar to background noise.

CDMA Sequencing

CDMA Sequencing Techniques


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Relationship between Frequency,Power, and Spreading Factor

The block is a variable, its volumeis constant, only the sizes of theedges change.

Therefore, you can calculate the

volume as follows: Volume of block = L X B X H

Here, length is the frequency bandwhich is constant for WCDMA as 5MHz breadth is the spreading factorand height is the power.

The volume of the block is constantbefore and after transmission of thedata.

UMTS Radio Path Fundamentals - WCDMA


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WCDMA uses Direct Sequence spreading.

Spreading process is done by directly combining the basebandinformation to high chip rate binary code.

Spreading factors vary from 4 to 512 in FDD UMTS.

Direct Sequence Spread Spectrum (DSSS)


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Spreading factor value) Symbol rate (ksymbol/s) Channel bit rate (kb/s)

256 15 15

128 30 30

64 60 60

32 120 120

16 240 240

8 480 480

4 960 960

Spreading factorsymbol ratebit rate relationshipin the uplink direction


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Spreading factorsymbol ratebit rate relationshipin the downlink direction

Spreading factor value) Symbol rate (ksymbol/s) Channel bit rate (kb/s)

512 7.5 15

256 7.5 30

128 30 60

64 60 120

32 120 240

16 240 480

8 480 960

4 960 1,920


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Frequency Division DupluexingTime Division Duplexing


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The WCDMA Carrier Bandwidths defined for the WCDMA, 5, 10, and 20 MHz.

5 MHz is the most commonly used bandwidth.

10 and 20 MHz alternatives will provide more capacity, but the occupancies occurringin the desired frequency band set some limits.

WCDMA Carrier


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UMTS FDD mode makes use of Frequency Division Duplexing

In the case of UMTS in Europe: The Uplink band is between

1.92 and 1.98GHz

The Downlink band is between

2.11 and 2.17GHz

The Uplink/Downlink Separation

is 190MHz

Principles of Radio Duplex: FDD

Downlink and Uplink Bandwidth in FDD


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Frequency Division Duplexing

1.8

GHZ

1.85

GHZ

1.9

GHZ

1.95

GHZ

2.0

GHZ

2.05

GHZ

2.1

GHZ

2.15

GHZ

2.2

GHZ

1.92

GHZ

1.98

GHZ

2.11

GHZ

2.17

GHZ

UMTS

UPLINK

UMTS

DOWNLINK

.

.

.

.

.

..

.

.

.

190 MHz


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FDD Air Interface

Parameter Value

Multiple Access Scheme Direct Sequence CDMA

Duplex Method FDD

Chip Rate 3.84 Mcps

Carrier Spacing 5 Mhz

Frame Length 10 msSlot per Frame 15

No. of Chips/Slot 2560 Chips(max.2560 bits)

Inter-Cell Synchronization None

Spreading Factor Variable ( 4-512)

Uplink SF 4-256

Downlink SF 4-512

User Data Rate 8->384 Kbps


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TDD supports variableasymmetry, which allows

operators to decide the capacitythat they want to allot to downlinkversus uplink servers.

This improves the effectivenessof the available spectrumresources because data trafficpatterns tend to heavily favordownlink.

Principles of Radio Duplex: TDD

Downlink and Uplink Bandwidth in TDD


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1. UMTS TDD Solutions provideenhanced performance by

supporting peak downlink sectorcapacities of up to 12Mbps.Even the average capacities persector provided by UMTS TDDare thrice as high when

compared to other commercialmobile platforms.

2. UMTS TDD solutions are costeffective when compared to

other technologies and thesecosts will reduce further whenthis globally accepted standardis produced at a higher scale.

Advantages of UMTS TDD

3. UMTS TDD improves spectralefficiency with the help of its N=1

frequency reuse standard. Thisstandard allows networkoperators to deploy a network thatuses multiple towers using onlyone 5 MHz RF channel for a 3.84

Mcps (Mega Chip per second)system or one 10 MHz channelfor a 7.68 Mcps system.

4. UMTS TDD subscribers alsobenefit from better connectivity

within the network footprint whilethey are mobile and traveling at aspeed more than 120 km/hr.UMTS TDD supports Tower-to-tower handoff as well as network-

to-network roaming.


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Spreading, Scrambling & Channelization


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Spreading means increasing the signal bandwidth

Spreading includes two operations: Channelization (increases signal bandwidth) - using orthogonal codes

Scrambling (does not affect the signal bandwidth) using pseudo noise codes

Spreading in WCDMA

Channelization code (SF)

Data

Bit rate Chip rate Chip rate

Scrambling Code


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Channelization codes are orthogonal codes

These are based on Orthogonal Variable Spreading Factor (OVSF)

They are of length 4 - 512 chips long (1.04-133.34s) depending on thechannel and required bit rate of the service.

Channelization codes are used for channel separation both in uplink anddownlink direction.

In DL, it can separate different users within one cell/sector. Channelization codes have different spreading factor values and

therefore different symbol rates.

The channelization code length is one symbol.

Channelization Codes


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SF = 1 SF = 2 SF = 4

ch,1,0 = (1)

ch,2,0 = (1,1)

ch,2,1 = (1,-1)

ch,4,0 = (1,1,1,1)

ch,4,1 = (1,1,-1,-1)

ch,4,2 = (1,-1,1,-1)

ch,4,3 = (1,-1,-1,1)

Channelization Code Tree


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In the scrambling process the code sequence is multiplied with apseudorandom scrambling code.

Only one primary scrambling code is allocated for a cell.

The scrambling code can be a long code or a short code Code period is of 10 ms

Gold Code with 10 ms period or short code S(2) code

In the downlink, scrambling codes are used to reduce the inter-basestation interference

In the downlink direction, always long scrambling codes are used.

In the uplink direction, there are millions of scrambling codes available.

All uplink channels may use either short or long scrambling codes

Long codes are used if the base station uses the RAKE receiver.

Scrambling Code


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Codes Channelization code Scrambling code

Usage

Uplink: Separation of physicaldata and control channels fromthe same terminalDownlink: Separation ofdownlink dedicated userchannels

Uplink: Separation ofterminalsDownlink: Separation ofsectors (cell)

LengthVariable (depends on the userallocation)

Fixed

Numberof codes

Depends on the spreadingfactor (SF)

Uplink: Several millionsDownlink: 512

Scrambling and Channelization Codes


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Difference between the Channelization and Scrambling codes

Scrambling and Channelization Codes


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In WCDMA, the terminal employs a RAKE receiver to handle Multipathpropagation.

The RAKE consists of receivers, adjustable-by-system delayfunctionality, code generator, and gain and phase tuning equipment.

Rake Receiver


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Simplified Block Diagram of the RAKE Receiver

Rake Receiver


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UMTS Air Interface


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Preparing the Data and Signaling for the UMTS Air Interface (Uu)

UMTS Air Interface Overview


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One basic frame is divided into15 slots, with each slot

measuring 2/3 ms in length.

The frame length is 10 ms. Thistiming structure is mainlyrequired for the synchronization

Signal arrangements does notimpact the Channelization

Every WCDMA frame isnumbered by the System FrameNumber (SFN) according to the3GPP specifications.

This has been done to ensurethe inter-operability betweenGSM and WCDMA.

DS-WCDMA-FDD Frame


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Chip

A chip is a bit of the code signal usedfor signal multiplication.

The chip rate used in WCDMA is3.84Mcps

This leads to a carrier bandwidth ofapproximately 5MHz

This chip rate can be generatedsimply from existing GSM clock rates

The size of one chip in time is 1 / 3840 000 seconds

Air Interface: Chip and Symbol

Symbol

A symbol is a data unit transmittedover the Air Interface.

In the downlink transmission, eachsymbol represents two bits.

Bits can be represented as a tuple(x1, y2).

In the tuple, x1 and y2 each representone bit.


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WCDMA Channels


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Channel Organization in UMTS


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There are three types of channels across the air interface and accessstratum that we are interested in:

Logical Channels Between the RLC and MAC layers

Transport Channels Between the MAC and Physical layers

Physical Channels

Between Physical Layers at the Node-B and UE

UMTS Air Interface Channel Structure


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Control Channels BCCH Broadcast Control Channel

PCCH Paging Control Channel

CCCH Common Control Channel

DCCH Dedicated Control Channel

Traffic Channels

DTCH Dedicated Traffic Channel

CTCH Common Traffic Channel

Major Logical Channels


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The Broadcast Control Channel (BCCH) Its a downlink channel for broadcasting system control information

The Paging Control Channel (PCCH) Its a downlink channel that transfers paging information

The Common Control Channel (CCCH)

Its a bi -directional channel transmitting control information between UEs and theUTRAN

The Dedicated Control Channel (DCCH) Its a point -to-point bidirectional channel transmitting control information between a

specific UE and the UTRAN

Logical Control Channels


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The Dedicated Traffic Channel (DTCH) Its a point -to-point channel dedicated to a single UE for the transfer of user

Information

The Common Traffic Channel (CTCH) Its a point -to-point unidirectional channel for transfer of user information to a group of

UEs

Logical Traffic Channels


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Common Control Channels BCH Broadcast Channel

FACH Forward Access Channel

PCH Paging Channel

RACH Random Access Channel

CPCH Common Packet Channel

Dedicated Channels DCH Dedicated Channel

DSCH Downlink Shared Channel

Major Transport Channels

C T Ch l


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The Broadcast Channel (BCH) Its a cell -wide channel that is used to broadcast system and cell-specific information.

The BCH is always transmitted over the entire cell with a low fixed bit rate.

The Forward Access Channel (FACH) Its a downlink channel that is used to carry control information to a UE when the

system knows the location cell of the UE. May also carry short user packets.

The Paging Channel (PCH)

Its a cell -wide channel that is used to carry control information to a UE when thesystem does not know the location cell of the UE

The Random Access Channel (RACH) Its an uplink control channel from the UE. May also carry short user packets

The Common Packet Channel (CPCH)

Its a contention based uplink channel used for transmission of burst data traffic.

Common Transport Channels

D di t d T t Ch l


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The Downlink Shared Channel (DSCH) Its a downlink channel shared by several UEs carrying dedicated control or traffic

data.

The Dedicated Channel (DCH) Its a channel dedicated to one UE used in uplink or downlink.

Dedicated Transport Channels

M j Ph i l Ch l f UMTS


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Common Control Channels P-CCPCH Primary Common Control Physical Channels (DL)

S-CCPCH Secondary Common Control Physical Channels (DL)

P-SCH Primary Synchronization Channel (DL)

S-SCH Secondary Synchronization Channel (DL)

CPICH Common Pilot Channel (DL)

AICH Acquisition Indicator Channel (DL)

PICH Paging Indicator Channel (DL) PDSCH Physical Downlink Shared Channel (DL)

PRACH Physical Random Access Channel (UL)

PCPCH Physical Common Packet Channel (UL)

AP-AICH Access Preamble Acquisition Indicator Channel (DL)

CD/CA-ICH Collision Detection/Channel Assignment Indicator Channel (DL)

Major Physical Channels for UMTS

M j Ph i l Ch l f UMTS


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Dedicated Channels

DPDCH Dedicated Physical Data Channel (DL & UL)

DPCCH Dedicated Physical Control Channel (DL & UL)

Major Physical Channels for UMTS

C Ph i l Ch l f UMTS


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The Primary-Common Control Physical Channels (P-CCPCH) It is used to carry broadcast information across the cell

The Secondary-Common Control Physical Channels (S-CCPCH) It is used to carry paging and forward access information across the cell

The Primary-Synchronization Channel (P-SCH) It is used during cell search to provide timing information

The Secondary-Synchronization Channel (S-SCH) It is used during cell search to provide information about

the primary scrambling codes in use in the cell

The Common Pilot Channel (CPICH)

It is used to provide the phase reference for downlink channels

Common Physical Channels for UMTS

how toget

synchronised?

C Ph i l Ch l f UMTS


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The Acquisition Indicator Channel (AICH) It is used to acknowledge random access requests

The Paging Indicator Channel (PICH) It is used to enable discontinuous reception of the SCPCCH

The Physical Downlink Shared Channel (PDSCH) It carries traffic to one or more users

The Physical Random Access Channel (PRACH) Its a contention based channel used for random access and to transmit small packets

of information

The Physical Common Packet Channel (PCPCH) Its an extension to the RACH used to carry larger packets of information on the uplink

The Access Preamble Acquisition Indicator Channel (AP-AICH)

It is used to indicate the reception of a preamble signature for Random Access

The Collision Detection/Channel Assignment Indicator Channel (CD/CA-ICH) It is used to indicate collisions and channel assignment for packet access

Common Physical Channels for UMTS

D di t d Ch l


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The Dedicated Physical Data Channel (DPDCH) It is used to carry user information

The Dedicated Physical Control Channel (DPCCH) It is used to carry dedicated control information regarding its associated DCHs

Dedicated Channels

FDD d L i l d T t Ch l DL


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FDD-mode: Logical and Transport Channel DL

BCCHBroadcast Control Channel,(system information)

PCCHPaging Control Channel(paging & notification)

CCCHCommon Control Channel(control information withoutRRC connection)

DCCHDedicated Control Channel(power control, TFI, etc.)

DTCHDedicated Traffic Channel(user data)

Logical Channels (content)

BCH

Broadcast Channel,

PCHPaging Channel

FACHForward Access Channel

DSCHDownlink Shared Channel

DCHDedicated Channel

Transport Channels

dedicatedtransportchannels

common

transportchannels

FDD mode Logical and Transport Channel UL


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FDD-mode: Logical and Transport Channel UL

CCCH

Common Control Channel(control information withoutRRC connection)

DCCHDedicated Control Channel

(power control, TFI, etc.)

DTCHDedicated Traffic Channel(user data)

Logical Channels (content)

RACH

Random AccessChannel

CPCHCommon Packet Channel

DCHDedicated Channel

Transport Channels

dedicatedtransportchannels

commontransportchannels

DS WCDMA FDD Channels


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DS-WCDMA-FDD Channels


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HSDPA & HSUPA

High Speed Downlink Packet Access


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HSDPA is the first evolutionary step for the 3GPP WCDMA architecture

It is specified in the Release 5 of the 3GPP standards.

HSDPA enhances the peak download data rate from the current 384kbps up to a theoretical maximum downloading peak rate of 14.4 Mbps.

In RAS05 the maximum supported peak downloading rate is 1.8 Mbps.

The increase in the downlink data rate and the actual cell throughput aredue to three main factors:

adaptive modulation and coding

fast scheduling

fast retransmission.




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The introduction of HSDPA to the 3G network mainly affects the RadioAccess Network, which consists of the Base Station (BTS), the RNC,

and the UE. The basic functionality of HSDPA




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The Data Rate in HSDPA




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Adaptive Modulation in HSDPA




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Hybrid Automatic Retransmission Quest


High Speed Uplink Packet Access


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High Speed Uplink Packet Access (HSUPA) defines a new radiointerface for the uplink communication.

HSUPA was introduced in Release 6.

HSUPA is also known as FDD Enhanced uplink or E-DCH.

Following key features are introduced with HSUPA to achieve this: A new dedicated uplink channel Enhanced Dedicated Channel (E-DCH)

Introduction of HARQ (Hybrid Automatic Retransmission request )

Fast Node B Scheduling in uplink - introduction of MAC

Support of Macro diversity ( Soft Handover) Shorter TTI of 2 ms




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Benefits of the HSUPA

The user data rates, the delay properties, the cell throughput and the

cell coverage are important properties that partly characterize theefficiency of the mobile network system.

The HSUPA is designed to improve all these properties and thus enableimproved user experience that brings added value for end users andnetwork operators.

The coverage gain is between 0.5 and 1.5 decibels.

In the HSUPA, the half rate, three to- four ratio rate and four-to-four ratiocoding rates are defined by the 3GPP specifications.


Introduction to High Speed Uplink Packet Access


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Transmission in HSUPA

Introduction to High Speed Uplink Packet Access


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UMTS Traffic Management

Databases Used in Traffic Management


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Databases Used in Traffic Management

Temporary subscriber identities


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Temporary subscriber identities

UMTS Traffic Bearer Classes


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UMTS Traffic Bearer Classes

Characteristics of a Bearer


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The following figure describes the Network Bearer:

The following figure explains data and speech is routed through the

bearer:




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Managing the Bearer Through The Network

The UMTS network is responsible for establishing a flexible bearer for

subscriber data transport between the Mobile Terminal (MT) and theexternal networks.

The following figure explains the QoS management in the control plane:


Types of bearer


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A bearer has different parameters, such as variable data rates,protection and delay.

The bearer is dependent on the service required.

RNC makes the decision about bearer

Types of bearer

Transmission over the network


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Transmission over the network

The above figure demonstrates this transmission through the useof pipes between elements in the network

Bearer Transmission in the Network

Characteristics of a Network Bearer


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The type of the bearer is reserved and the way it is routed through thenetwork depends on the subscriber's service need.

To better understand this concept, consider two examples: Voice Traffic

Internet Connection

Characteristics of a Network Bearer



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Managing the Bearer over UTRAN

The following figure shows how the different RABs are received by the

RNC and combined together to form a single RRC connection:


Management of the radio bearer


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3G MSC

Mobile has a single RRC

RNC

RNC

RNC3G SGSN



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a age e t o t e ad o bea e

As the subscriber moves a secondconnection is made for a cell on the

same site (softer handover)

RNC

RNC

RNC

3G SGSN

3G MSC



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g

As the mobile continues then thefirst link is dropped, and a second

cell is added from another site (softhandover)

NOTE: Those BTS with anactive connection are

known to be part of theactive set.

RNC

RNC

RNC

3G SGSN

3G MSC



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g

As the mobile continues then the second linkis dropped, and a second cell is added from

another RNC. A soft handover is possible asthe Iur interface exists.

The RNC is known as the serving(S-RNC) and the new RNC is the drift

(D-RNC). Note that the Iu connection isstill from the S-RNC.

RNC

RNC

RNC

3G SGSN

3G MSC



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g

As the mobile continues, the third connectionis dropped. The S-RNC has no active

connection's itself, so the Iu-RRC connection ismoved to the D-RNC.

RNC

RNC

RNC

3G SGSN

3G MSC



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g

Finally, the mobile is now in area where the forthconnection is dropped and the new site selected is

under another RNC. The S-RNC does not have an Iurinterface to the target RNC, so the core network isused to assist in the handover.

RNC

RNC

RNC

3G SGSN

3G MSC


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Procedures in UMTS Networks

Basic model of UMTS network transactions


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Paging

RRC Connection Setup

Transaction Reasoning

Authentication and Security

Transaction Setup &

Radio Access Bearer Allocation

Transaction

Transaction Clearing &

Radio Access Bearer Release

RRC Connection Release

Radio network (Control Plane)System Network (Control Plane)

Radio network (Control Plane)






Radio network (Control Plane)

Paging Procedure


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Paging Type 1 is used by CNdomains.

Paging those UEs who are in idlemode (no RRC connection).

g g

Paging Type 2 is used for pagingthose UEs who are in cell

dedicated channel (RRCconnected).

Paging Type 1 Paging Type 2

RRC Connection Setup Procedure


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When a UE needs networkservice, it triggers RRC

connection setup procedure.

The UE sends RRC ConnectionRequest (in message part ofPRACH) from the cell where it

camps.

RNC decides to set up RRCconnection in dedicated channel(DCH) or common channels.

The UE sends RRC ConnectionSetup Complete to the RNC.

p

Transaction setup with RAB allocation


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Simplified Bearer Establishmentfor a Call

It includes RAB Assignment andRAB Release Requestprocedure.

Circuit Switch Domain Packet Switch Domain

RAB allocation is the first stepwhere the different nature of CN

domains has to be taken intoaccount.

RRM Procedure Soft Handover


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Soft Hand Over - link addition

RRM Procedure Soft Handover


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Soft Hand Over - link deletion

CS Inter System Hand Over (ISHO) from theUTRAN to the GERAN


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UTRAN to the GERAN 3GPP specifications define HO between two radio accesses to be a

mandatory requirement of the system.

MM Procedure


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URA updateCell update

UE performs cell update when: Cell reselection.

Periodic cell update. Uplink data transmission. Paging response. Re-entering the service area.

The RNC maintains theregistration of the current URA

for each UE. URA consists of a number of

cells belonging to either oneRNC or several RNCs.

Routing area update to the CN PS domain


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The UEs latest RA differs from the one stored in the USIM, the UE

initiates a Routing Area Update (RAU) transaction.

Packet data transferuplink and downlink


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While moving UE has to first carry out cell update and ensure thatSRNC has the valid location information.

IMS registration procedure


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The objective of IMSregistration is to register and

authorize an IMS user.

Identities used in IMS are: User private identity.

User public identity

Home Network Domain The IP address allocated for the

UE in the visited network.

IMS session establishment


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Consider UE A is on themove and the GPRS

connection terminates at thehome network GGSN).

UE B is located in the homenetwork.

Fig. shows a signalingdiagram of UE A contactingUE B.

IMS Session establishmentstarts with a SIP inviterequest.

User Authentication


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The UE and the network authenticate each other by sending the MMauthentication request message.

UE responds with an MM authentication response message.


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Transport Technologies in UMTS


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PDH

PDH Plesiochronous Digital Hierarchy


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PDH employs PCM multiplexing techniques

PDH is one of the most widely used transmission techniques

The basic rate of data transfer in Europe consists of 32 multiplexed basePCM channels offering 2 Mbps (E-1)

Coaxial cable, optical fibre and radio links are applied for PDH at ratesover 2Mbps

3 different multiplexing standards exist in PDH technology:

1) European Standard: E1s2) North American: T1s

3) Japanese: JT1s

PDH Plesiochronous Digital Hierarchy


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397200 Kbit/s

97728Kbit/s

32064 Kbit/s

274176 Kbit/s

44736 Kbit/s

6312 Kbit/s

1544 Kbit/s

564992 Kbit/s

139264 Kbit/s

34368 Kbit/s

8448 Kbit/s

2048 Kbit/s

64 Kbit/s

X 4

X 3

X 4

X 4

X 4

X 4

X 6X 3

X 3

X 30X 24

X 4

X 5X 7

PDH Multiplexing : 3 Standards

Japanese Standard North AmericanStandard European Standard

primary rate

2. Order

3.

4.

5.

PDH Multiplexing


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CarrierEquipment

PrimaryMux

4th OrderMux

3rd OrderMux

2nd OrderMux

E1 - 2 MB

E4 - 140 MB

E3 - 34 MB

E2 - 8 MB

CarrierEquipment

PrimaryMux

4th OrderMux

3rd OrderMux

2nd OrderMux

E1 - 2 MB

E4 - 140 MB

E3 - 34 MB

E2 - 8 MB

Non standard Non standardEOW

Supervisory

Through channels

DroppedChannels

DroppedChannels

PDH Limitations


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Inability to identify individual channels in a higher-order bit stream

Insufficient capacity for network management

Most PDH network management is proprietary

There is no standardised definition of PDH bit rates greater than 140

Mbit/s

There are different hierarchies in use around the world. Specializedinterface equipment is required to interwork between two hierarchies.


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SDH

Why SDH?


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Provides solution to PDH Problems

First world standard in digital format with optical Interface standardized

Simple drop and insert of traffic channels

(direct access to lower level systems without synchronization)

Simpler multiplexing

(low SDH level can be directly identified from higher SDH level)

Allows mixing of SDH and PDH systems

Backward and forward compatibility: Backward compatibility to existingPDH, Forward compatibility to future B-ISDN, etc.

STM-1 Frame


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RSOH

MSOH

AU Pointer

9 261

270 columns (byte)

9rows(b

ytes)

2430 bytes/frame 8 bit/byte 8000 frame/s = 155.52 Mbit/s

transmitted from top to bottom and left to right

Payload

VC-4

3

5

P

O

H

STM-1 Frame Structure and SOH


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RSOH

MSOH

A U P T R

STM-1 PAYLOAD

261 bytes9 bytes

Section Overhead

9

rows

AU Pointer(s)

RSOH

MSOH

}

}: bytes reserved for national use

A1 A1 A1 A2 A2 A2 J0

B1 E1 F1D1 D2 D3

B2 B2 B2 K1 K2

D4 D5 D6

D7 D8 D9

D10S1 Z1 Z1 Z2 Z2 M1 E2

D11 D12

SDH Hierarchy Formation


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SDH Synchronization & Timing Distribution


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SDH Synchronization & Timing Distribution


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SDH Synchronous Digital Hierarchy Clock Supply Hierarchy


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ATM Basics

Contents


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Synchronous and Asynchronous Multiplexing

Network Transfer Mode

ATM Technology ATM Cell

ATM in 3G Networks

ATM Connections

ATM Switching

Synchronous and Asynchronous Multiplexing


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CACCC

A A

C C C C

A

CACAB

A A

BB B BB B B B

BB BB B

C

ABC

Asynchronous

Multiplexing

SynchronousMultiplexing

C

BB

CC

B

C

Network Transfer Modes


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Synchronous Transfer Mode

Packet Transfer Mode

Asynchronous Transfer Mode



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Derived from TDM technology

Divides the physical bandwidth into logical timeslots

Circuit switched networks (voice and leased lines)



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Benefits: Fixed and guaranteed bandwidth

Low and fixed delay Less delay variation (jitter)

Drawbacks: Waste of physical bandwidth in data networks

No over-subscription in the service provider network

Inflexible bandwidth, not ideal for burst traffic

Maximum number of connection equals maximum number of timeslots

Ideal for uncompressed voice networks



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X.25 or Frame Relay technology A DLCI identifies each virtual connection

( DLCI : Destination Link Control ID)



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Benefits: Less waste of physical bandwidth in data networks

Over-subscription in the service provider network is possible Guaranteed bandwidth is possible (CIR) Committed Information Rate.

Drawbacks: No guarantees for delay and jitter

Ideal for data networks with less demand of the quality of service

Variable length and delivery of packets Flexible bandwidth



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A compromise for voice, data, and video QoS defined/negotiated when the initial connection is made Asynchronous on layer 2 of the OSI reference model

Compromise of STM and PTM

Voice Video Data

ATM cells

48-octetPayload

ATM 53-octet cells areswitched in hardware



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Benefits: Over-subscription in the service provider network possible

Guaranteed bandwidth, delay and jitter are possible Proven technology

Drawbacks: Most applications are based on IP instead of ATM

A lot of overhead for IP over ATM

Complicated protocol architecture

Implemented in voice and data networks

Transport layer in 3G networks

What is ATM?


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ATM = Asynchronous Transfer Mode

Fast packet switching and multiplexing technology (cell-based )

Support the universe of services voice, video and data traffic

Provides quality of service guarantee and reliability

Offers "bandwidth on demand"

Connection-oriented, no error correction for user traffic error correction for user traffic is handled by the end user

the advantages are increased speed of switching and elimination of associated delay

Utilises statistical multiplexing less bandwidth can be reserved than if bandwidth reservation would be based on the peak rate

of the connections.

transmission cost saving is achieved

Why is ATM used as transport network in 3G?


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ATM provides efficient support for transmission of voice, data, and video

ATM provides QoS guarantee and reliability

ATM utilises statistical multiplexing, so less bandwidth can be reserved

transmission cost saving are considerable

ATM supports the soft handover functionality

ATM Cell


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Header contains routing and error control information

Payload carries the actual user information, either voice, data or video

Header5 bytes

Payload48 bytes

53 bytes

ATM interfaces in 3G network


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UNI User Network InterfaceNNI Network Node Interface

PSTNMGW MSCBSUE

A BIu-CSIubUu

UNI NNI

IP networkGGSN

Iu-PS

NNI

RNC

SGSN

RNCBS

BS

Iur

NNI

UNI

UNI

ATM is employed

Gn Gi

ATM Cell

Provides local functions such as The 1st bit - indicates whether the cell


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GFC Generic Flow ControlVPI Virtual Path IdentifierVCI Virtual Channel Identifier

PT Payload TypeCLP Cell Loss PriorityHEC Header Error Control

User Network Interface (UNI) Network Node Interface (NNI)

VCI

GFC VPI

VPI

VCI

VCI PT CLPHEC

123457 68

VCI

VPI

VPI

VCI

VCI PT CLPHEC

123457 68

Payload Payload

Header(5 bytes)

Payload(48 bytes)

Provides local functions, such asidentifying multiple stations thatshare a single ATM interface

The 1st bit - indicates whether the cellcontains user data or control dataThe 2nd bit - indicates congestion

Indicates two levels of priorityfor ATM cells, CLP=1 should bediscarded in preference to cellswith the CLP=0

ATM Cell Header


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GFC provides local functions.

VPI indicates the virtual path over which the cell should be routed.

VCI identifies a virtual channel over which the cell is to travel.

PT discriminates between a cell carrying management information orone, which is carrying user information.

CLP indicates two levels of priority for ATM cells.

HEC checks for an error and corrects the contents of the header byusing a CRC algorithm.

Coding of the PT field in ATM header


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PT code Interpretation

000 User data cell No congestion More data to come

001 User data cell No congestion Last cell

010 User data cell Congestion More data to come

011 User data cell Congestion Last cell

100 Virtual Channel Segment OAM flow F5

101 Virtual channel end to end OAM flow F5

110 Resource Management Cell

111 Reserved

ATM Virtual Path (VP) and Virtual Channel (VC)

ATM L


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48 bytes5 bytes

HEADER PAYLOAD

ATM cell (53 bytes)

ATM Layer

Transmissionpath

VirtualPath (VP)

Virtual

Channel (VC)ATM Cell

Si lifi d k hi

Advantages of Virtual Path Connections


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Simplified network architecture

Increased network performance and reliability

The network deals with fewer, aggregated entities Segregation of traffic

A form of priority control can be implemented by segregating traffic types requiringdifferent quality of service (QoS)

Reduced processing and short connection setup time

New VCCs can be established by executing simple control functions at the end pointsof the VPC; no call processing is required at transit nodes

it can decrease the connection setup delay

Enhanced network services The user may define closed user groups or closed networks of VC bundles.

Virtual channel and virtual path switching


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VPI 3

VPI 8

VPI 36

VPI 23 VPI 9

VP switch

Port

VCI 9VCI 10

VCI 9VCI 10

VCI 15

VCI 26

VCI 9VCI 10

VC switch

Port

Port

ATM cross-connect (AXC)RNC

C O G CO C C


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VC2 / VP2

VC1 / VP1

ATMswitch

VC1 / VP1

BTS 1

AXC

VC3 / VP3VC3, VC4 / VP4

VC3, VC4, VC5, VC6 / VP7VC5 / VP5

VC6 / VP6

VC1/VP1 THROUGH-CONNECTED IN AXC2

VC/VP CROSS-CONNECTION TABLEVC3/VP4 VC3/VP 7VC4/VP4 VC4/VP 7VC5/VP5 VC5/VP 7VC6/VP6 VC6/VP 7

AXC / ATM switch

BTS 2

AXC

BTS 3

AXC

BTS 4

AXC

BTS 5

AXC

BTS 6

AXC

StandaloneAXC

Statistical Multiplexing Gain


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For a group of bursty connections,less bandwidth can be reservedthan if bandwidth reservationwould be based on the peak rate

of the connections

Most of the traffic sources sendbursty traffic and with a highprobability all the sources do notsimultaneously transmit at their

peak rate One of the proposed advantages

of ATM is that statisticalmultiplexing gain can be utilized

Statistical multiplexing gain

Statistical multiplexing Deterministic multiplexing

Requiredbandwidth

Peak cell rate of

traffic type 1

Peak cell rate oftraffic type 2

Peak cell rate oftraffic type 3


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Thank YouCognitel Training Services (P) Ltd.

A-10, Infocity-I, Sector-34, GurgaonHaryana (INDIA)-122001

www.cognitel.in

Documents

3G Training Print Day2 7th June 2011