Asymptotic SER analysis and optimal power sharing for dual-phase and multi-phase multiple-relay cooperative systems

The asymptotic high-SNR symbol error rate (SER) performance of selective decode-and-forward (DF) 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 diversefading channels such as η − μ, κ − μ, shadowed-Rician scenarios and each for non-identical fading for the source-destination (SD), 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 (MIMO)-orthogonal space time block codes (OSTBCs), cooperative beamforming, joint transmit/receive antenna selection, free space optical (FSO) scenarios etc. This high-SNR analysis provides valuable insights into the impact of the diversity orders of the SR and RD links on the end-to-end SER as wellas 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.