Two-way amplify and forward relaying with adaptive modulation

Abstract

Cooperative diversity has been recently presented as a new technique to improve the link performance of wireless communication systems. However, a loss in spectral efficiency due to half-duplex relaying can be a significant weak-point for high data rate communications. In this paper, we propose two-way amplify-and-forward relaying in conjunction with adaptive modulation in order to improve spectral efficiency of relayed communication systems while monitoring the required error performance. By using the ideal-scaled gain at the relay instead of the more practical power-scaled gain, we provide an approximate but a very accurate performance analysis of our proposed system. Our numerical examples show that the proposed system offers a considerable gain in the spectral efficiency and outage probability while satisfying the error rates requirements.