Exact BER of rectangular-constellation QAM subjected to asynchronous co-channel interference and Nakagami-m fading

Introduction: Conventionally, the rectangular QAM (R-QAM) BER has been estimated by using various approximations or bounds. Most exact QAM BER results are obtained without taking into account the co-channel interference (CCI) [1, 2]. When CCI is considered, exact BER analyses procedures are performed only for BPSK [3–5] and QPSK [4, 5] systems. Hence, the contribution of this Letter is that we derive an exact BER expression for R-QAM systems corrupted by both asynchronous CCI and Nakagami-m fading, while dispensing with the Gaussian distributed CCI assumption.