Analysis and Algorithms for Power Allocation in Decode-And-Forward Cooperative Relaying

We investigate fundamental characteristics of cooperative transmission in terms of power efficiency. To do this, we first propose an optimal power allocation method for wireless cooperative networks with Rayleigh fading. By introducing the concept of “cooperative region”, we then evaluate the average power efficiency which is defined as the ratio of total consumed transmit power with cooperation to that of direct transmission and show how the average performance depends upon the QoS requirement, path loss exponent, distance between source and destination and on node density. Analytical results are supplemented by simulation results to demonstrate the energy saving of cooperation transmission. With a better understanding of cooperative transmission, we further propose several relay selection strategies based on optimal power allocation in cooperative networks with multiple transmission. Some properties i.e., selfless, selfish and fairness are justified in each strategy.