By the aid of CDMA or Code division multiple access, speaking at different frequency division and speaking in different directions or spatial divisions have become possible. In radio CDMA, individual groups are offered a shared code. The codes can have same channel, but a particular code can only be understood by users related to it.
CDMA is also associated to cellular technology. CDMA developed by Ericsson, has high capacity and little cell radius. CDMA is also used in digital cellular telephony systems where there are convenience of multiple access. QUALCOMM and W-CDMA of the International Telecommunication Union (ITU) have used digital cellular telephony. CDMA device is also used in navigation devices like OmniTRACS Satellite System and Global Positioning System.
CDMA or Code division multiple access is randomly used in mobile phones. The standard of CDMA used here is IS-95. IS is an Interim Standard of the US Telecommunications Industry Association. It is a generation 2 cellular CDMA brand. CDMA is also in the process of being approved as mobile air interface standard.
In Global System for Mobile Communications (GSM) specifies an entire network infrastructure whereas CDMA handles the air interface of the radio technology specifically. The infrastructure of GSM has an international standard, while CDMA offers freedom to each operator to provide network that best suits them. There are two kinds of CDMA technology namely synchronous CDMA and asynchronous CDMA. The asynchronous CDMA are more advantageous than Synchronous CDMA , TDMA and FDMA. The spectrum can be used more effective in mobile telephone technologies. Though CDMA, FDMA and TDMA have more or less the same spectral efficiency but there are certain aspects that regulate their technology like timing is an important factor in the case of TDMA, power control is a vital factor in CDMA and in FDMA the greatest factor is the generation of frequency. Asynchronous CDMA allows flexible allotment of resources. Specific number of orthogonal codes, frequency bands are allotted for CDM, TDMA and FDMA systems that cannot be applied in an inconsistent and packet data transmissions. In a noisy traffic environment that happens mostly in mobile networks, Asynchronous CDMA allows random fluctuation of its performance. Moreover Asynchronous CDMA is is specially designed to suit in a mobile network with huge number of transmissions. Some of the exclusive features that have led to the popularity of CDMA are - pseudonoise code assigned to each user, soft handoff, wide bandwidth and no requirement of frequency planning.
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