Relay OFDMA System for Wireless Multimedia Services in Home Area Networks

We design the wireless multimedia services system using orthogonal frequency division multiple access (OFDMA) schemes allowing cooperative relays in home area networks. The multihop transmission scheme by relay stations provide reliable services to users in dead spots like the cellar or the garden. For this system, we propose an adaptive subcarrier and transmit power allocation method that maximizes the system total data rate in a downlink transmission. We generally formulate the total data rate maximization problem and develop a resource allocation scheme to solve it. The scheme is derived via two parts: allocating the resource for users and making a decision to relay or not. Since these two works influence each other, the subcarriers and power should be assigned in consideration of whether to relay or not. We compare the performance of the proposed method with existing resource allocation schemes, the 1-hop transmission with dynamic resource allocation and 2-hop transmission with fixed resource allocation. By relaying and scheduling gain, the total data rate of the proposed scheme is greater than those of other schemes, and grows as the number of users in the system increases due to multiuser diversity effects.