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M-Ary Amplitude Shift Keying Ofdm System, Fuqin Xiong
M-Ary Amplitude Shift Keying Ofdm System, Fuqin Xiong
Electrical and Computer Engineering Faculty Publications
Coherent M-ary amplitude-shift keying (MASK) is proposed for use in orthogonal frequency-division multiplexing (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 bit-error rate (BER) of M-ary quadrature amplitude modulation (QAM) OFDM and a better BER than that of M-ary phase-shift keying (MPSK) OFDM. The √M-ary ASK OFDM has the same peak-to-average-power ratio as that of the M-ary QAM OFDM. The MASK OFDM can be implemented digitally and efficiently by fast cosine transform and demodulated by inverse fast cosine transform. Comparisons show that …
Frequency-Hopped Multiple-Access Communications With Noncoherent M-Ary Ofdm-Ask, A. Al-Dweik, Fuqin Xiong
Frequency-Hopped Multiple-Access Communications With Noncoherent M-Ary Ofdm-Ask, A. Al-Dweik, Fuqin Xiong
Electrical and Computer Engineering Faculty Publications
A noncoherent, bandwidth-efficient modulation scheme is proposed for frequency-hopping multiple-access (FH-MA) networks. The proposed scheme is a combination of noncoherent M-ary amplitude-shift keying (NMASK) and orthogonal frequency-division multiplexing (OFDM). Using this scheme minimizes the required data bandwidth. The number of frequency slots available to the users increases significantly for a fixed spread-spectrum bandwidth (BWSS). The effect of the multiple-access interference is reduced. Simple and accurate bit error rate expressions have been derived for FH-OFDM-MASK in additive white Gaussian noise channels and for FH-OFDM-ASK in Rayleigh fading channels.