A high-efficiency semi-distributed resource allocation in OFDMA-based wireless relay networks

In this paper, the problem of semi-distributed resource allocation is considered in an orthogonal frequency division multiple access (OFDMA) downlink transmission of wireless relay networks, where subcarriers are allocated to the relay stations at the base station (BS) only with a small part of channel state information (CSI), and afterwards subcarrier and power are allocated to the users at the relay stations with perfect CSI. A high-efficiency semi-distributed algorithm of linear complexity is proposed to address the joint resource allocation, which observably reduces the computational complexity of the subcarrier allocation at the BS and alleviates the uplink transmission of CSI feedback from the relay stations. It is shown through numerical evaluation that the performance of the proposed semi-distributed algorithm is close to the optimal joint subcarrier and power allocation, which is of exponential complexity and requires entire CSI at the BS.