Gsm

INDUSTRIAL TRAINING

Presented By:- Vishal Balana

Roll no:- 02104041

Date:- 15th july 2005

Hutchison Essar South Ltd.

(punjab)

Introduction Hutchison Max Telecom Pvt. Ltd. is a joint promotion by

Max and Hutchison Whampoa Ltd. (HWL) of Hong Kong. The Company holds licenses to provide cellular services in Mumbai, Gujrat, Kolkata, Chennai, Andhra Pradesh, New Delhi and Karnatka. The services are provided in the city of Mumbai under the brand name of ORANGE

Today with a subscriber base of 5.8 lacs subscribers ORANGE covers whole of Mumbai and Navi Mumbai. ORANGE has a superior coverage spread through various cell Sites across Mumbai. The company has International tie-ups for roaming customers as well as all India roaming. The inherent strength of the Network lies in the fact that ORANGE Mumbai has its own network backbone to carry its signal, thus, making the Company totally self dependent. As per the figures released by COAI (Cellular Operators Association of India), Hutchison Telecom is 2nd largest cellular service provider in India.

The Chaos That Existed

Before GSM networks, there were public mobile radio networks. They normally used analog technologies, which varied from country to country and from one manufacturer to another. These analog networks did not comply with any uniform standard. There was no way to use a single mobile phone from one country to another. The speech quality in most networks was not satisfactory.

Due to increasing use of radio communications throughout Europe, the frequency band was also getting congested.

The Birth of GSM

In 1982, the Conference of European Posts & Telecommunications Administrations (CEPT) established a committee called “Groupe Special Mobile” (GSM). This committee was set up to specify a unique radio communication system for Europe. This system came to be known as GSM.

In 1992, to avoid confusion between the GSM system and the GSM committee, the GSM system was renamed as “Global System for Mobile” and the committee was now called “Special Mobile Group” (SMG).

In 1988, the European Telecommunications Standards Institute (ETSI) was created to specify the standards for GSM.

GSM- Architecture

MS

BTS

BTS

BTS

BTS BTS

BTS

BTS

BTS

BSC

BSC

PSTN

VLR

TRAU HLREIR

OMC

SMSC

AUC

VMSC

MSC

Abi

s

A

OML

GSM – System Architecture

A typical GSM system is made up of the following components:

Mobile Switching Centre (MSC)

Base Station Controller (BSC)

Base Transceiver Station (BTS)

Transcoder (XCDR)

Messaging System

GSM – Cell Architecture

Features of GSM

Flexibility & increased capacity.

Compatibility – Support for international roaming.

Security – Distinction between user and device identification.

Noise Robust – Excellent speech quality.

Wide range of services.

Inter-working (e.g. with ISDN, DECT).

Feature: Flexibility

In analogue air interface, every connection between a mobile subscriber and a cell site requires a separate RF carrier.

In GSM, 8 simultaneous conversations can be carried out on one RF carrier.

The system is more versatile and it is possible to move capacity from one part of the network to another just by reconfiguring the system database.

Feature: Compatibility & SecurityCompatibility:

ISDN is a new & advanced standard in telecommunications

GSM is compatible with ISDN

GSM phones are ISDN compatible

Security:

In analogue systems, anyone can ‘eavesdrop’ if equipped with an appropriate receiver.

GSM offers high speech & data security.

In GSM, the calls are digitized, encoded and then ciphered (encrypted) before transmission. This makes listening to calls virtually impossible.

GSM – Air Interface

Frequency Band Used

Logical Channels

Frequency Hopping

Air Interface: Freq Band GSM 900:

Uplink: 890 - 915 MHz (MS to base station)

Downlink: 935 - 960 MHz (base station to MS)

124 RF carriers.

200 KHz bandgap.

GSM 1800 (previously DCS-1800):

Uplink: 1710 - 1785 MHz

Downlink: 1805 - 1880 MHz

GSM 1900 (previously PCS-1900):

Uplink: 1850 - 1910 MHz

Downlink: 1930 - 1990 MHz

Air Interface: Logical Channels

Traffic Channels

Signalling Channels

Dedicated Channels

Broadcast Channels

Common Control Channels

Air Interface: Freq. Hopping

Provide Diversity.

Reduce Interference.

Mobile transmits on one frequency during

one TS.

Switches to different frequency to transmit

during next TS.

Broadcast channel does not support hopping.

Sequence of Learning

Projects

Transmission

RF maintenance

OMC-R (Operations

and Maintenance-Radio)

Functions of OMC-R

The OMC-R performs the following functions:

Direct management of BSS and RXCDR and the links between them.

Management of the NE devices associated with the links (on the RXCDR side) between the MSC, the BSSs and RXCDRs. This is all done using the O&M data packets sent to/from the NE.

Monitoring of events and alarms, performing fault handling, NE re-configuration, NE software uploading and downloading, and performance data collection and reporting for all the NE under its control.

Provides a centralized facility for network management of up to 120 NEs with up to 45,000 traffic channels for the OMC-R.

OMC-R N/W Management

Fault Management Event/Alarm Management Performance Management Configuration Management Load management

Fault Management

Fault management provides the facility to change the status of any device using fault handling procedures. From the OMC-R, the GSM network operator can react to changes in the network and re-configure the site by taking devices in or out of service as required, thus maintaining continuity of service to mobile phone users. Fault management tasks can be performed from the map, the alarm window, Navigation Tree and through contained devices

Event/Alarm Management

A primary function of an OMC-R is to maintain the quality of service to customers/users of the GSM network by monitoring the state of Motorola equipment in the network. Event or alarm messages containing information on the state of the network, devices and links in the system are sent, via the X.25 network, to the OMC-R.There is the optional Alarm notification via Paging feature which automatically notifies key personnel of certain alarm or state changes. Operators can filter and select the way in which alarms are displayed and handled; for example, alarms which have been handled, but not yet cleared, can be deferred.An optional Network Health Analyst (NHA) provides a means by which operators can move from being purely reactive to a more proactive role by observing a combination of events, statistical information and configuration data that notifies them of network problems before any faults are raised..

Performance Management

Performance management provides collection and reporting of network performance statistics. The OMC-R collects, processes and stores performance statistics on the different NEs in the network, and provides reporting facilities for the presentation and printing of the processed statistics. These statistics can be then used to analyse network performance and aid long term planning.

Configuration Management

The OMC-R provides the configuration management facilities for a system that can cater for an expanding GSM network. The System Processor can be configured for a variety of expandable traffic channel capacities on the same basic platform. The OMC-R system allows customers to expand their network operations and maintenance support in line with their business growth and provide orderly migration for existing users and rapid deployment for new users.The OMC-R also includes the Call Trace function. Optional tools may also include the Intelligent Optimization Product (IOP) and the Motorola Analysis and Reporting System (MARS).

Load management

Load Management forms part of the Configuration Management and provides the operator with a central location to remotely load all the NEs with the latest compatible version of operating software. New software loads are installed at the OMC-R and later downloaded to the NEs under the OMC-Rs control

Connectivity dig.

Types of Links

Physical Links Logical Links

Physical Links

Path: A PATH device defines the connectivity between

a BSC site and BTS sites under its control. It is a logical representation of a 2 Mbit/s route between the BSC and a destination BTS. This connectivity specifies the physical route from the BSC, through intermediary BTSs to the destination BTS. A PATH may contain a route through a maximum of 10 BTS sites. The connection information between any two sites consists of an MSI (NIU for M-Cell)/MMS device at each end of the link.

Logical Links

Operation and Maintenance Link (OML) Message Transfer Link (MTL) Radio Signaling Link (RSL) XCDR to BSC Link (XBL) Cell Broadcast Link (CBL)

Operation & Maintenance Link (OML)

The purpose of the OML is to provide communication between an OMC-R and a BSC or RXCDR for transferring network management (O&M) data. Up to four OML links can be configured between an OMC-R and BSC or RXCDR; one OML is used at any one time, the other three OMLs exist for redundancy purposes.

Message Transfer Link (MTL)

The purpose of the MTL is to provide a link for signalling information between the BSC and the MSC. In the Motorola system, when local transcoding is used, this is a physical connection between the BSC and the MSC. When a Remote Transcoder is used, the logical MTL is made up of two physical parts; the connection between the BSC and the RXCDR and the connection between the RXCDR and the MSC. When more than one MTL is configured between the BSC and MSC, both load sharing and redundancy are present. Up to 16 MTLs may be configured between a BSC and MSC.

Radio Signaling Link (RSL)

A signalling link between a BSC and a remote BTS is called a Radio System Link (RSL). The purpose of an RSL is to provide signalling information between a BSC and a remote BTS. The Motorola software chooses the timeslots used, automatically. This is to ensure that new BTSs, added to the network, can be communicated with on default timeslots. Each RSL link is associated with a PATH. It is possible to have multiple (up to eight) RSLs between a BSC and a remote BTS. There are two RSLs between BTS2 and the BSC. This is possible because of the daisy chain connection in the BSS. The two RSLs provide both load sharing and redundancy functions for the signalling link.

XCDR to BSC Link (XBL)

An XBL link may be configured between the BSC and the RXCDR for exchanging internal Fault Management (FM) data between them. An Enhanced XBL (EXBL) will allow generic messaging between the RXCDR and BSC in support of current and future operator needs.

Cell Broadcast Link (CBL)

A CBL link can be configured between the BSC or RXCDR and the Cell Broadcast Centre (CBC). This is used for downloading messages to broadcast along with other necessary information such as repetition rate and number of broadcasts.

Site Containment

Information flow b/w OMC & NE

Thank You……