Springer Science+Business Media
In this paper, the authors consider a transmission control problem in Network-Coded Two-Way Relay Channels (NC-TWRCs), where the relay buffers randomly packets from two users and the channels are assumed to be fading. The problem is modeled by a discounted infinite horizon Markov Decision Process (MDP). This paper is to find an adaptive transmission control policy that minimizes the packet delay, buffer overflow, transmission power consumption and downlink error rate simultaneously and in the long run. By using the concepts of sub modularity, multi modularity and L-convexity, they study the structure of the optimal policy searched by Dynamic Programming (DP) algorithm.