GSM AND BASICS OF 3G

SUBMITTED BY:BHANU PRATAP SHARMA

11470102810ECE-B

INTRODUCTION TO GSM

• GSM (Global System for Mobile Communications, is a standard set developed by the European counteries.Telecommunications Standards to describe protocols for second generation (2G) digital cellular networks• GSM networks operate in a number of different carrier

frequency ranges with most 2G GSM networks operating in the 900 MHz or 1800 MHz bands.• Extended GSM (EGSM) EGSM has 10MHz of bandwidth

on both transmit and receive. Receive bandwidth is from 880 MHz to 890 MHz Transmit bandwidth is from 925 MHz to 935 MHz

FEATURES OF GSM• CompatibilityThe need for a common standard for mobile

telecommunications was set up to co-ordinate the complicated task of specifying the new standardized network.

• Noise RobustIn order to combat the problems caused by noise, GSM uses

digital technology instead of analogue.• Improved Security With GSM, both the Mobile Equipment (ME) and Mobile

Subscriber are identified. The subscriber is authenticated by use of a smart card known as a Subscriber Identity Module (SIM)

GSM Architecture

Mobile station• MS consists of two parts, the Mobile Equipment (ME) and an

electronic ‘smart card’ called a Subscriber Identity module (SIM).

• Hardware has an identity number associated with it, which is unique for that particular device and permanently stored in it.

• This identity number is called the International Mobile Equipment Identity (IMEI)

Base Station System (BSS)• The BSS communicates with the MS over the digital air

interface • The BSS consists of three major hardware components• The Base Transceiver Station – BTSThis is the part of the GSM network which communicates with

the MS. The antenna is included as part of the BTS.• The Base Station Controller – BSCThe BSC as its name implies provides the control for the BSS.

The BSC communicates directly with the MSC. The BSC may control single or multiple BTS.

• The Transcoder The Transcoder is used to compact the signals from the MS so

that they are more efficiently sent over the terrestrial interfaces.

Network Switching System• Main function is to manage communications between the

GSM network and other telecommunications networks.• The components of the Network Switching System are listed

below: Mobile Services Switching Centre – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR

Mobile Services Switching Centre (MSC) The functions carried out by the MSC are

Call ProcessingIncludes control of data/voice call setup, inter-BSS and inter-MSC handovers and control of mobility management (subscriber validation and location).

Operations and Maintenance SupportIncludes database management, traffic metering and measurement, and a man–machine interface.

Home Location Register (HLR)The parameters stored in HLR are•Subscribers ID •Current subscriber VLR.•Supplementary services subscribed to.•Supplementary services information.

Visitor Location Register (VLR)

•The VLR provides a local database for the subscribers wherever they are physically located

•This function eliminates the need for excessive and time-consuming references to the “home” HLR database.

Equipment Identity Register (EIR)The EIR database consists of lists of IMEIs (or ranges of IMEIs) organized as follows:White ListContains those IMEIs which are known to have been assigned to valid MS equipment.Black ListContains IMEIs of MS which have been reported stolen or which are to be denied service for some other reason.Grey ListContains IMEIs of MS which have problems (for example, faulty software).

GSM Interfaces• The interfaces comprise all the connections between the GSM

system .• Um interface- The "air" or radio interface standard that is used

for exchanges between a mobile (ME) and a base station (BTS / BSC).

• A interface- The A interface is used to provide communication between the BSS and the MSC.

• B interface- The B interface exists between the MSC and the VLR• C interface- The C interface is located between the HLR and a

GMSC

GSM Channelization• There are two types of channels in GSM Physical channels and

logical channels.

• Physical ChannelsThe physical channel is the medium over which the information

is carried, in the case of a terrestrial interface this would be a cable.

• Logical channels.The logical channels consist of the information carried over the

physical channels. They are of two types control and traffic channels.

GSM HANDOVER

• One of the key elements of a mobile phone or cellular telecommunications system, is that the system is split into many small cells to provide good frequency re-use and coverage. However as the mobile moves out of one cell to another it must be possible to retain the connection. The process by which this occurs is known as handover or handoff.

Requirements for GSM handover• The process of handover or handoff within any

cellular system is of great importance. It is a critical process and if performed incorrectly handover can result in the loss of the call.

• Dropped calls are particularly annoying to users and if the number of dropped calls rises, customer dissatisfaction increases and they are likely to change to another network.

HSDPA• HSDPA provides packet

data support, reduced delays and a peak raw data rate (i.e. over the air) of 14 Mbps. • The improvement in

speed and latency reduces the cost per bit .• Standard values for

HSDPA are 3.6,7.2,14.4

HSUPA• HSUPA provides

improved uplink packet support, reduced delays and a peak raw data rate of 5.74 Mbps• The enhanced uplink

increases the data rate up to 5.8 Mbit/s.• Standard values for

HSUPA are 384kbps,2mbps,5.76

BENEFITS OF HSPA

•Use of higher order modulation•Shorter Transmission Time Interval (TTI)•Use of link adaptation

Basics of 3G

• 3G, short for 3rd Generation, is a term used to represent the 3rd generation of mobile telecommunications technology

• 3G finds application in wireless voice telephony, mobile Internet access, Fixed Wireless Internet access, video calls and mobile TV.

• The communication spectrum between 400 MHz to 3 GHz was allocated for 3G. Both the government and communication companies unanimously approved the 3G standard.

FEATURES OF 3G

•Data rates•Security•Evolution Of 3GPP and 3 GPP2

THANK YOU