Optimal Asymmetric Resource Allocation and Analysis for OFDM-Based Multidestination Relay Systems in the Downlink

We propose an asymmetric resource allocation (ARA) scheme for the downlink wireless multidestination relay systems with orthogonal frequency-division multiplexing modulation. Unlike the previous work, the transmission durations at the source (base station) and the relay are designed to be asymmetric, which enhances the degree of freedom for transmission. Therefore, the proposed ARA scheme achieves a higher system capacity than existing symmetric resource allocation schemes, and it is also proven to be optimal. Simulation results demonstrate that the proposed asymmetric time allocation has a significant effect on the system performance with a larger number of users, a longer source-to-destination distance, and when there is a significant difference between the source-to-relay and relay-to-destination distances. Furthermore, the ARA scheme has a fast convergence speed.