Resource allocation for cooperative relay-assisted OFDMA networks with imperfect CSI

This work addresses the radio resource allocation (RRA) problem for cooperative relay assisted OFDMA wireless networks. The relays adopt the decode-and-forward protocol and can cooperatively assist the transmission from source to destination. The RRA scheme addresses practical implementation issues of resource allocation in OFDMA networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, the source only knows estimated channel status and distributions of related estimation errors. The objective is to maximize the system throughput of the source-to-destination link under various constraints. Since the optimization problem is known as NP-hard, we divide the original problem to three subproblems including relay selection, subcarrier and power allocations. We derive theoretical expressions for the solutions and illustrate them through simulations. Results validate clearly that our proposed RRA algorithm can enhance the performance of system with imperfect CSI compared to the other newly proposed resource allocation schemes.