Adaptive modulation and coding for two‐way relaying with amplify‐and‐forward protocols

Abstract

In this study, the authors introduce adaptive modulation and coding in a two‐way amplify‐and‐forward (AF) relay network to improve the system performance. They consider a cooperative system where two user nodes exchange information with the assistance of multiple two‐way AF relays. In the proposed scheme, the user nodes adaptively choose the appropriate modulation and coding scheme to ensure that the frame error rate (FER) satisfies the system requirement; all relays are utilised to forward the received signals to the user terminals. Furthermore, they provide a better approximation of the cumulative distribution function of the destination signal‐to‐noise ratio; and thus, derive more accurate expressions including average spectral efficiency and average FER in closed‐form, over Rayleigh fading channels. The theoretical analysis is verified by numerical results.