Relay-Assisted Diversity Communications

Relaying and diversity methods improve wireless communications by jointly exploiting the benefits of node cooperation, multiple-channel reception, and distributed processing. We develop a framework for design and analysis of relay-assisted diversity communications accounting for: 1) node positions; 2) link characterization; 3) diversity methods; 4) distributed coding and constellation signaling; and 5) power allocation. The framework is built on a simple model for assessing the frame error probability (FEP) as a function of radio-link characteristics, and it enables a clear understanding of how the aforementioned aspects affect the performance. A novel FEP-optimal power allocation is developed and compared with other allocation techniques such as uniform, destination-balanced (D-balanced), and relay-balanced (R-balanced) power allocations. Results show the effectiveness of the novel power allocation technique for various distributed codings and provide insights into the operation of relay-assisted diversity systems.