Optimal Resource Allocation for Reliable and Energy Efficient Cooperative Communications

Cooperative communication for wireless networks has gained a lot of recent interests due to its ability to mitigate fading with exploration of spatial diversity. The objective of this paper is to design an efficient algorithm to minimize the total consumed power of the network while guaranteeing transmission reliability of multiple active transmission pairs through cooperative wireless communications. This problem has not been studied and is much more challenging than relay assignment considered in literature work which simply targets to reduce the transmission power for a single transmission pair. We achieve the objective by jointly considering transmission mode selection, relay assignment and power allocation. This requires us to solve a combinatorial optimization problem, namely Reliable and Energy Efficient Cooperative Communication problem (REECC), which is a hard problem as its complexity increases exponentially with the number of relay nodes. We propose an iterative solution framework by testing different power levels to find the optimal solution. To reduce the computational cost, we design several novel techniques in the solution framework. The simulation results demonstrate that our solution can run very efficiently to obtain the minimum total consumed power while satisfying the reliable transmission requirement.