Mobile Phone

Global System for Mobile communication is the most popular standard for mobile phone in the world.The key advantage of GSM system to consumer has been better voice quality. The advantage for network operators has been the ease of deploying equipment. Mobile phone connect to it by searching for cell in the immediate vicinity. GSM networks operate in four different frequency ranges. Most GSM networks operate in the 900 Mhz or 1800 Mhz bands. Mobile phone and the network they operate under vary significantly from provider to provide and country to country. However, all of them communicate through electromagnetic radio wave. The phone have a low-power transceiver that transmits voice and data to the nearest cell site usually not more than 8 to 13 km away. When the mobile phone or data device is turned on, it register with the mobile telephone exchange. Gsm has used a varity of voice code to squeeze 3.1 kHz audio into between 5.6 and 13 kbit/s. Originally,two codecs,named after the types of data channel. There are four different cell size in GSM network-macro,micro,pico and umbrella cells. The coverage area of each cell varies according to the implementation environment. Micro cells can be regarded as cell where the base station antenna is installed on a mast or a building above average roof top level.