Error rate and diversity order of multinode cooperative communications in dissimilar nakagami fading channels

Cooperative communications has been recognised as an effective technique to combat multi-path fading impairment and to provide additional diversity advantage for small-size and low-power-consumption mobile terminals. A class of decode-and-forward (DF) relaying serial cooperative communications, in which each node is assumed to be able to determine whether the received signals can be successfully decoded or not, has recently been proposed and analysed over Rayleigh fading channels. Since the Nakagami fading channels represent a wide variety of realistic channels, such serial cooperative networks should be investigated over such channels before putting into real applications. In this paper, we analyse the performance of such serial cooperative transmission systems thoroughly over dissimilar Nakagami fading channels. We derive a closed-form symbol-error-rate expression for the case of M-ary phase shift keying (PSK) modulation. Moreover, we evaluate the system diversity property and investigate the achievable diversity order under two specific channel conditions. Finally, we perform simulations to verify the theoretical findings.