Sum power minimization in access point selection with superposition coding scheme

How to minimize the sum power is a major concern when allocating multiple users to several access points in a downlink wireless communication system. In this paper, we propose an optimal superposition coding scheme and a very simple sub-optimal scheme. Then, we compare them with time-sharing schemes. Simulation results show that the superposition coding schemes perform much better than the time-sharing schemes because it uses much less transmit power at the same outage probability. In addition, the sub-optimal superposition coding scheme is close to the optimal superposition coding scheme in performance but with a lower complexity.