Adaptive Power Allocation for Regenerative Multi-Relay System Based on Capacity-Approaching Distributed Space-Time Codes

The idea of distributed space-time codes which is being applied to wireless relay network, seems to be a promising approach to reduce the total radiated power and to insure the delivery of the information with desired quality of service. In this paper, we propose a feasible coding scheme based on distributed linear dispersion codes (LDC) for two-hop regenerative multi-relay scenario, and further analyze the advantage of the proposed case in terms of capacity gains over the system with orthogonal transmission. Moreover, we show how to effectively allocate the limited resource among the source and relay terminals in order to maximize the performance of the proposed system. Numerical results indicate that with the adaptive scheme, the proposed system not only achieves higher capacity gains than the system with direct transmission and traditional uniform PA, but also performs very close to the optimum relay system.