Power Allocation and Subcarrier Pairing Algorithm for Regenerative OFDM Relay System

Relayed transmission is a promising technique that helps in attaining broader coverage and in combating the impairment of the wireless channel. Orthogonal frequency division multiplexing (OFDM) technique is promising for the next generation wireless communication system. Therefore, the combination of two techniques named OFDM-relay will be a good candidate technology for future wideband wireless communication. This paper investigates the resource allocation of two-hop regenerative OFDM relay system with/without diversity. Optimization of power allocation (PA) is proposed to maximize the channel capacity and subcarrier pairing strategy is adopted to improve the system performance further. In addition, the resource allocation for multi-hop OFDM system without diversity is also presented. The resource allocation is based on the instantaneous channel state information (ICSI) and aims to maximize the system capacity. The order pairing strategy is proved to be a good choice for multi-hop regenerative OFDM relay system without diversity. The simulation results show that combining with the pairing algorithm, efficient power allocation will greatly improve the system capacity.