ABSTRACT
FDMA was one of the earliest multiple access techniques for cellular systems. In this technique, the available bandwidth for a given service is divided into a number of subchannels, which are allocated to individual users on request. Since users exclusively occupy their subchannels all the
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time, FDMA does not require synchronization, and hence it is simple to implement. However, to minimize adjacent channel interference, unused frequency slots, that is guard bands, are introduced between neighboring subchannels. This leads to a waste of bandwidth. In addition, when continuous transmission is not required for a user, bandwidth goes wasted since its allocated bandwidth is not in use. FDMA is used as the principal multiplexing technique in radio and television broadcast and in the first-generation (1G) cell phone systems, such as the advanced mobile phone system (AMPS) and wireless metropolitan area network (WMAN) [2].
