Two-way signal space cooperative network with a DF relay — Outage and optimization

Two-way cooperative relay network links two source terminals using bidirectional connection to exchange information with the help of a relay. The conventional two-way cooperative network with a decode-and-forward (DF) relay takes six time slots to transfer four symbols due to half-duplex transmission. If signal space diversity is integrated into a conventional two-way cooperative network, the resultant system transfers four symbols in three time slots, which is referred to as two-way signal space cooperative network (2W-SSD-DF). In this paper, 2W-SSD-DF system is investigated for its outage performance and system optimization. Closed-form expression of the outage probability of 2W-SSD-DF system over Rayleigh fading channel is derived and its asymptotic expression is also obtained to study the influence of various system parameters. In addition, system optimization of the system is examined and a framework to allocate optimal power to the transmitting nodes is developed in order to enhance the outage performance of the system. Finally, the analytical work is validated through Monte Carlo simulations.