Date Added: Aug 2010
Harsh wireless channel conditions, scarce bandwidth, and limited power resources require intelligent allocation schemes which can efficiently exploit channel variations. OFDMA is a multi-carrier modulation and multiplexing technique which divides the wide-band frequency selective wireless channel into a set of orthogonal narrow-band channels and provides immunity from Inter-Symbol Interference (ISI). In a multi-user system, different sub-carriers can be allocated to different users without interference. Due to the multi-carrier nature of OFDMA systems, enormous opportunities exist for dynamic sub-carrier and power allocation strategies.