Relaying Power Allocation with User-Cooperation for OFDM-Based MISO Broadcast Channels

This paper addresses the power allocation problem on relaying channels with user-cooperation for multi-user orthogonal frequency division multiplexing (OFDM) systems. The proposed problem is based on dual-mode mobile stations (MSs), where one interface is used to receive signals from a base station (BS) and the other is used to forward the signals to nearby MSs through out-of-band relaying. This dual-mode operation enables MSs to cooperate with one another without consuming the capacity of a broadcast channel. Theoretically, the cooperation among MSs over orthogonal relaying channels has already been defined as conferencing. The proposed scheme uses conferencing to consider a broadcast channel with user-cooperation, where mobile power is distributed among subcarriers. Simulation results demonstrate that the proposed scheme achieves improved performance over the equal-power-allocation scheme on relay channels and the conventional broadcast scheme. These results are shown by considering the average throughput and the outage throughput.