GSM Wireless Communications (1)

GSM Wireless Communications (1)

GSM

Definition:

GSM (Global System for Mobile Communications), is a TDMA based wireless network technology developed in the European Telecommunications Standards Institute (ETSI) that is used throughout most of the world to describe protocols for second generation (2G) digital cellular networks used by mobile phones.

The GSM standard was developed as a replacement for first generation (1G) analog cellular networks, and originally described a digital, circuit switched network optimized for full duplex voice telephony. This was expanded over time to include data communications, first by circuit switched transport, then packet data transport via GPRS (General Packet Radio Services) and EDGE (Enhanced Data rates for GSM Evolution or EGPRS).

Further improvements were made when the 3GPP developed third generation (3G) UMTS standards followed by fourth generation (4G) LTE Advanced standards.

GSM carrier frequencies:

GSM networks operate in a number of different carrier frequency ranges (separated into GSM frequency ranges for 2G and UMTS frequency bands for 3G), with most 2G GSM networks operating in the 900 MHz or 1800 MHz bands. Where these bands were already allocated, the 850 MHz and 1900 MHz bands were used instead (for example in Canada and the United States). In rare cases the 400 and 450 MHz frequency bands are assigned in some countries because they were previously used for first-generation systems.

Basic GSM Network structure:

The network is structured into a number of discrete sections:

ü The Base Station Subsystem (the base stations and their controllers).

ü The Network and Switching Subsystem (the part of the network most similar to a fixed network). This is sometimes also just called the core network.

ü The GPRS Core Network (the optional part which allows packet based Internet connections).

ü The Operations support system (OSS) for maintenance of the network.

GSM coverage plain:

To provide coverage for a large service area of a mobile network we have two Options:

(A) Install one transceiver with high radio power at the center of the service area

         Disadvantages:

ü The mobile equipments used in this network should have high output power in order to be able to transmit signals across the coverage area.

ü The usage of the radio resources would be limited.

(B) Divide the service area into smaller areas (cells)

          Advantages:

ü Each cell as well as the mobile handsets will have relatively small power transmitted.

ü The frequency spectrum might be “reused” in two far separated cells.

 -----------------------------------------------------------------

 GSM wireless Communication channel,wireless Communications channel,

4G Communications, GSM wireless Communications channel

 GSM wireless Communication channel,wireless Communication channel,

 GSM wireless Communications channel,wireless Communications channel,

 GSM wireless Communication channel in 4G communication,wireless Communication channel in 4G communication ,

 GSM wireless Communications channel in 4G communications,wireless Communications channel in 4G communications,

 GSM 4G wireless Communication channel,4G wireless Communication channel,