Noncoherent MT-MFSK signals with diversity reception over bandwidth constrained and Nakagami fading channels

This paper studies the performance of diversity applied to an efficient modulation/coding scheme using M-ary frequency shift keying (MFSK) signals, with postdetection noncoherent diversity reception and combining over slow nonselective Nakagami m-distribution fading channels. This modulation/coding scheme is referred to as multiple tone MFSK (MT-MFSK) and is implemented based on balanced incomplete block design (BIB-design) from combinatorial theory. In MT-MFSK modulation, the number of tones used to represent the signal set is reduced compared to the conventional MFSK modulation, and each MT-MFSK signal is represented by a number of distinct orthogonal tones selected according to BIB-design. This mechanism drastically increases the bandwidth efficiency of the modulated signal and allows the modulator to create implicit frequency diversity. In this paper we show that by combining the implicit frequency diversity of MT-MFSK signals with the diversity reception introduced by employing multiple receiving antennas, substantial improvements in performance can be obtained.