Opportunistic Relaying with Limit Feedback in Two-Way Relaying over OFDM with Subcarrier Mapping

Two-way relaying is an efficient way to improve the network capacity significantly. Subcarrier mapping (SCM) has been shown to evidently improve the average end-to-end capacity in OFDM relay networks. However perfect channel knowledge is required, which leads to large feedback amount of channel state information (CSI). In this paper, the multi-relay scenario of two-way relaying over OFDM based on sub-carrier mapping is investigated. An opportunistic relaying scheme with limit feedback CSI is proposed. The transmission scheme, which is based on instantaneous channel quality, is selected to offer maximum the system capacity. The simulations show that the proposed approach can achieve almost asymptotically performance as full CSI feedback scheme with large number of sub-carriers.