Selective Subcarrier Pairing and Power Allocation for Decode-and-Forward OFDM Relay Systems

This paper investigates a Decode-and-Forward (DF) two-hop relaying system in which Orthogonal Frequency Division Multiplexing (OFDM) is used. The relay forwards the message received from the source on a subset of available subchannels in the second time slot. Firstly, a pairing and selecting algorithm is proposed. Then, power will be allocated to the both base station and relay station under individual power constraints in order to maximize the capacity. The pairing and selecting algorithm and resource allocation is based on instantaneous channel state information (ICSI). Finally, the simulation results show that selective relaying combined with subcarrier pairing and power allocation will improve the system capacity to a considerable extent.