Performance analysis of spectrum sharing-based multi-hop decode-and-forward over Nakagami-m fading channels subject to additive white generalised Gaussian noise

In this work, the authors study the performance of decode-and-forward cognitive multi-hop networks in an underlay spectrum sharing strategy for Nakagami-m fading channels with additive white generalised Gaussian noise. To this end, new exact analytical expressions for the average bit error rate of M-ary quadrature amplitude modulation (M-QAM) and M-ary phase shift keying are derived and evaluated. In addition, an exact expression for the average symbol error rate of M-QAM is provided. Moreover, lower- and upper-bound expressions for the ergodic capacity are obtained. Different scenarios are presented to study the influence of various key system parameters, such as fading severity, noise shaping parameter, and interference temperature, on the system performance. The obtained analytical results are supported with Monte Carlo simulations to confirm the accuracy of the analytical derivations.