Adaptive Hybrid Scheme for Cooperative Communications

Abstract

Future wireless communication networks require stringent specifications in terms of much higher bit rates and reduced network energy usage. In this paper, a hybrid adaptive relaying technique is proposed to toggle between the full duplex (FD) and the half duplex (HD) relaying modes and at the same time selects between amplify-and-forward (AF) and decode-and-forward (DF) protocols according to certain criteria. The toggling between the FD and the HD relaying modes is carried out to improve the data rates with a trade-off in the bit-error-rate (BER) performance. FD has full data rate at the expense of the residual self interference (RSI) which deteriorates the BER performance. On the other hand, HD does not suffer from RSI, but it does so at the expense of halving the data rate of FD. Moreover, toggling between AF and DF for the relay is a trade-off between good performance provided by DF at the expense of complexity. Complexity is reduced by using AF at the expense of higher BER. Thus, two toggling thresholds are determined in order to toggle between FD and HD, as well as AF and DF. The performance of the proposed hybrid adaptive mode is evaluated by means of BER and capacity curves.