M-ary amplitude shift keying OFDM system

Coherent M-ary ASK is proposed to be used in OFDM systems. The frequency separation between subcarriers is only 1/2T instead of 1/T. With a slightly wider bandwidth, an M -ary ASK-OFDM can achieve the same BER of M-ary QAM-OFDM and a better BER than that of MPSK-OFDM. The M -ary ASK-OFDM has the same Peak-To-Average-Power Ratio (PAPR) as that of the M-ary QAM-OFDM. The MASKOFDM can be implemented digitally and efficiently by fast cosine transform (FCT) and demodulated by inverse fast cosine transform (IFCT). Comparisons show that implementation complexity is reduced for AWGN channels with the use of the new scheme.