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WHY UMTS?

3G systems provides a global mobility with wide range of services

There are five main UMTS standardization areas: Radio Access Network,

Core Network, Terminals, Services and System Aspects and GERAN. UMTS is built on top of the existing GSM infrastructure and integrates both

packet and circuit data transmission.

Unlike GSM, UMTS is mainly based on CDMA scheme and now combines

it with TDMA.

UMTS900 system characteristics

Downlink band (MHz) 925-960

Uplink band (MHz) 880-915

Carrier separation(MHz) 5

Channel raster (KHz) 200

UMTS900 Advantages: Has a better coverage compared to UMTS at 2100 MHz

UMTS900 offers a considerably more cost efficient solution.

GSM and UMTS will be in co-existence and operated in adjacent channels.Security features1-Network access security User identity confidentiality

Entity authentication

Confidentiality Data integrity

Mobile equipment identification2-User domain security:

User-to-USIM authentication

USIM-Terminal Link

3-Application security: Secure messaging between the USIM and the network4-Security visibility and configurability

Core Network

RNS (Radio Network Subsystem)

RNC (Radio Network Controller)

Node B

Interfaces

Uu Interface (between UE and Node B)

Iu Interface (between CN and RNS)

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Iur Interface (between one RNS and another RNS)

Iub Interface (between RNC and Node B)

User Equipment (UE): By which the user can access the network.

1.UMTS Subscriber Identity Module (USIM)

2.Mobile Equipment (ME)

3G (UMTS) ArchitectureMain blocks:

Mobile Services Switching Center (MSC)

Visitor Location Register (VLR)

Gateway Mobile Switching Center (GMSC)

Home Location Register (HLR)

Gateway GPRS support node

GGSN

Serving GPRS support NodeSGSN

GPRS Support Node (GSN)

Operation And maintenance center (OMC)

AAA server and Home Agent

Air Interface

The UTRAN air interface uses QPSK or 16QAM. The modulation chip rate

is 3.84 Mcps.

There are two dedicated physical channels; DPCCH (for controlinformation) and the DPDCH (for user data).

UMTS Channel structure:

Logical channelsdefine what type of data is transferred.

Transport channelsdefine how and with which type of characteristics the

data is transferred by the physical layer.

Physical channels datadefine the exact physical characteristics of the radio

channel.

Handover in UMTS

Softer Handover (intra Node B/intra RNS)

Soft Handover (inter Node B/intra RNS)

Soft Handover (inter Node B/inter RNS/intra SGSN)

Soft Handover (inter Node B/inter RNS/inter SGSN)

Hard Handover: All the old radio links in the UE are removed before the

new radio links are established.