Outage probability and system optimization of SSD-based dual-hop relaying system with multiple relays

The conventional dual-hop relaying system, without a direct link between the source and the destination, transmits one symbol in two time slots. However, if signal space diversity (SSD) is integrated into the conventional dual-hop relaying system, it transmits two symbols in three time slots to enhance the spectral efficiency of the conventional dual-hop relaying system. In this paper, the outage performance of an SSD-based dual-hop relaying system with multiple decode-and-forward (DF) relays over Rayleigh fading channel is analyzed, and its closed-form expression is derived. Moreover, an asymptotic approximation of the outage probability is obtained and it is used to investigate the impact of different system parameters. Furthermore, system optimization for power is investigated to enhance the outage performance by allocating optimal powers to transmitting nodes. In the end, extensive computer simulations are performed to validate the analytical results.