Optimal Power Allocation for Multi-User Linear Network Coded Cooperation System

Linear network coded cooperation (LNCC), which deeply integrates cooperative communications and linear network coding, has been proposed to increase spectrum efficiency in wireless communications. However, the issue of optimal power allocation (OPA) for multi-user LNCC systems still remains open. This paper studies the OPA problems for a multi-user two-slot LNCC system which works in a many-to-one pattern. We first analyze and present the tight approximation of the outage probability of the multi-user LNCC system by fully considering the effect of path loss, the effectiveness of which is validated by Monte Carlo simulations. On the basis of the theoretical analyses on outage performance, we further investigate the OPA strategies for multi-user LNCC systems. Two OPA strategies under different optimization criteria, i.e., minimizing the total outage probability and jointly minimizing the outage probabilities for each user under the constraint of total power available, are proposed by utilizing genetic algorithms. To the best of our best knowledge, this is the first work on OPA for multi-user LNCC systems. Numerical results demonstrate that the proposed OPA strategies do achieve the OPA and improve the system’s performance.