Asymptotic SER Analysis and Optimal Power Sharing for Dual-Phase and Multi-Phase Multiple-Relay Cooperative Systems

The asymptotic high-signal-to-noise ratio (SNR) symbol error rate (SER) performance of selective decode-and-forward cooperative multiple relay-aided wireless systems is derived for
$M$
-PSK and
$M$
-QAM modulations. The proposed analysis considers both dual-phase and multi-phase relaying protocols. Furthermore, analytical results are also presented for optimal power allocation both at the source and at each of the relays, since it significantly influences the performance of cooperative communication. A novel aspect of the proposed framework is that the SER and optimal power allocation results derived are applicable to diverse fading channels such as
$\eta -\mu $
,
$\kappa -\mu $
, and shadowed-Rician scenarios and each for non-identical fading for the source–destination, source–relay (SR), and relay–destination (RD) links. The applicability of the proposed framework is also demonstrated for diverse PHY layer schemes, such as multiple-input multiple-output-orthogonal space–time block codes, cooperative beamforming, joint transmit/receive antenna selection, and free-space optical scenarios. This high-SNR analysis provides the valuable insights into the impact of the diversity orders of the SR and RD links on the end-to-end SER as well as on the optimal power allocation factors both in the dual-phase and multi-phase protocols of various fading channels and schemes. Our simulation results verify the analytical results derived.