FUNDAMENTALS OF GSM

 What is the purpose of a cellular mobile communications system?

The purpose of a cellular mobile communications system is to provide a large number of low-power wireless transmitters to create cells, which serve as the basic geographic service area for a wireless communications system.

What is the function of variable power levels in a cellular mobile communications system?

Variable power levels in a cellular mobile communications system allow cells to be sized according to the subscriber density and demand within a particular region. This helps ensure efficient use of resources and optimal coverage for mobile users.

How are mobile conversations maintained as users travel from cell to cell?

As mobile users travel from cell to cell, their conversations are "handed over" between cells in order to maintain seamless service. This allows users to continue their conversations without interruption as they move from one cell to another.

What is the purpose of channel reuse in a cellular mobile communications system?

The purpose of channel reuse in a cellular mobile communications system is to maximize the use of available radio spectrum. By reusing channels in different cells, the system can accommodate a greater number of subscribers and provide more efficient service.

What are the important objectives of mobile communication systems?

The important objectives of mobile communication systems include providing anytime, anywhere communication; mobility and roaming capabilities; high capacity and subscriber density; efficient use of radio spectrum; seamless network architecture; low cost; innovative services; and a standard interface.

What is the first generation of technology in the cellular mobile communication system?

The first generation of technology in the cellular mobile communication system is 1G.

What was the first design of the 2G technology?

The first design of 2G technology was in 1980.

What year was 2.5G technology implemented?

2.5G technology was implemented in 1999.

What was the main service provided by 3G technology?

The main service provided by 3G technology was broadband data up to 2 Mb/s.

What is the standard for 4G technology?

The standard for 4G technology is WiMAX, HSOPA.

What was the main service provided by 2G technology?

The main service provided by 2G technology was digital voice and SMS.

What is duplexing?

Duplexing is the technique by which the send and receive paths are separated over the medium using transmission entities.

What are the two types of duplexing?

The two types of duplexing are Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD).

What is Frequency Division Duplexing (FDD)?

FDD uses different frequencies for the send and receive paths and there will be a forward band and reverse band. A duplexer is required if simultaneous transmission and reception is adopted, and the frequency separation between the forward band and reverse band is constant.

What is Time Division Duplexing (TDD)?

TDD uses different time slots for the transmission and reception paths. A single radio frequency can be used in both directions and no duplexer is required.

What type of duplexing does GSM use?

GSM uses Frequency Division Duplexing (FDD).

What is the frequency band for the Standard GSM 900 Band (P-GSM)?

The frequency band for the Standard GSM 900 Band (P-GSM) is 890 - 915 MHz for mobile transmit and 935 - 960 MHz for base receive.

What is the frequency band for the DCS 1800 Band?

The frequency band for the DCS 1800 Band is 1710 - 1785 MHz for mobile transmit and 1805 - 1880 MHz for base receive.

What are the uplink and downlink frequencies for Standard or Primary GSM 900 Band?

A: The uplink frequency is 890-915 MHz and the downlink frequency is 935-960 MHz.

What is the duplex distance and carrier separation for the Standard or Primary GSM 900 Band?

A: The duplex distance is 45 MHz and the carrier separation is 200 KHz.

What is the frequency band for DCS 1800 Band?

A: The frequency band for DCS 1800 Band is 1710 - 1785 MHz for mobile transmit and 1805 - 1880 MHz for base receive.

How many frequency channels are there in GSM 900 Band and DCS 1800 Band?

A: There are 124 frequency channels in GSM 900 Band and 374 frequency channels in DCS 1800 Band.

What is the voice coder bit rate for GSM 900 Band and DCS 1800 Band?

A: The voice coder bit rate for GSM 900 Band and DCS 1800 Band is 13 Kbps.

What is the modulation used in GSM 900 Band and DCS 1800 Band?

A: The modulation used in GSM 900 Band and DCS 1800 Band is GMSK.

What is the air transmission rate for GSM 900 Band and DCS 1800 Band?

A: The air transmission rate for GSM 900 Band and DCS 1800 Band is 270.8333 Kbps.

What is the access method used in GSM 900 Band and DCS 1800 Band?

A: The access method used in GSM 900 Band and DCS 1800 Band is FDMA/TDMA.

What is the speech coder used in GSM 900 Band and DCS 1800 Band?

A: The speech coder used in GSM 900 Band and DCS 1800 Band is RPE-LTP.

What type of duplexing is used in GSM 900 Band and DCS 1800 Band?

A: FDD (Frequency Division Duplexing) is used in GSM 900 Band and DCS 1800 Band.

What is the structure of the GSM network?

The GSM network structure is divided into different partitioned areas such as the GSM service area, IN service area, MSC service area, and Location area, and cells.

What is the purpose of dividing the GSM network into different areas?

The GSM network is divided into different areas to route incoming calls to the correct exchange and finally to the called subscriber. The mobility of all subscribers makes the structure of the network very important.

What is the PLMN service area in the GSM network?

The PLMN (Public Land Mobile Network) service area is a part of the GSM network. It refers to the area covered by a particular operator's network.

What is the MSC service area in the GSM network?

The MSC (Mobile Switching Center) service area is a part of the GSM network. It is responsible for routing calls and maintaining the subscriber's location information.

What is the Location area in the GSM network?

The Location area is a part of the GSM network. It refers to a geographical area where a mobile subscriber can move freely without triggering a location update.

What is a Mobile Station (MS)?

A Mobile Station (MS) is a device that includes radio equipment and a Subscriber Identity Module (SIM) that a subscriber needs to access the services provided by a GSM PLMN (Public Land Mobile Network). The MS can handle both data communication and voice communication.

What is an International Mobile Equipment Identity (IMEI)?

An International Mobile Equipment Identity (IMEI) is a number that is permanently stored in a Mobile Equipment (ME) and identifies each ME. The MS sends the IMEI to the MSC (Mobile Switching Center) upon request. The IMEI can be used to identify stolen or faulty mobile units.

What is a Mobile Subscriber ISDN Number (MSISDN)?

A Mobile Subscriber ISDN Number (MSISDN) is the number that the calling party dials to reach the subscriber. It is used by the land network to route calls to the appropriate MSC.

What is an International Mobile Subscriber Identity (IMSI)?

An International Mobile Subscriber Identity (IMSI) is the primary identity of a subscriber within a mobile network and is permanently assigned to the subscriber.

What is a Temporary Mobile Subscriber Identity (TMSI)?

A Temporary Mobile Subscriber Identity (TMSI) is a number assigned by the GSM system to identify a mobile. The TMSI can be changed periodically to protect the subscriber from being monitored by unauthorized entities.

What is a Subscriber Identity Module (SIM)?

A Subscriber Identity Module (SIM) is a removable smart card that is the size of a credit card and contains a microprocessor, RAM, and ROM. The SIM is inserted into the MS when the subscriber wants to make or receive a call. The SIM also stores a Personal Identification Number (PIN) which is compared with the subscriber's entered PIN.

What is a Base Transceiver Station (BTS)?

A Base Transceiver Station (BTS) is a network component that serves one cell and is controlled by a Base Station Controller (BSC). A BTS has radio transmission and reception devices and can handle multiple simultaneous communications.

What is a Base Station Controller (BSC)?

A Base Station Controller (BSC) is a network component in the PLMN that controls one or more BTSs. The BSC handles common control functions within the BTS.

What is a Transcoder/Rate Adapter Unit (TRAU)?

A Transcoder/Rate Adapter Unit (TRAU) is an equipment in which coding, decoding, and rate adoption for data is carried out. The TRAU is considered a subpart of the BTS, but can be located away from the BTS or between the BSC and the MSC.

What is the interface between the MSC and the BSS?

The interface between the MSC (Mobile Switching Center) and the BSS (Base Station System) is a standardized SS7 interface (A-interface). This allows the system operator to purchase switching equipment from one supplier and radio equipment and the controller from another.