Achievable SNR and rate regions for OFDM-based asynchronous two-way relay networks

In this paper, we develop an algorithm to characterize the achievable signal-to-noise ratio (SNR) and rate regions for an asynchronous bi-directional multi-carrier relay network. The network we consider is composed of two single-antenna transceivers and multiple single-antenna relays, thereby creating a multipath communication between the two transceivers. Each subcarrier is used to enable a bidirectional communication between two outer transceivers. In our data model, we assume that different relaying paths have different propagation delays. We aim to find the achievable rate region of such a network through optimal distributed beamforming at the relays and subcarrier power control at two transceivers. To do so, we introduce our optimization framework, analyze its structure, and show how it can be tackled.