Power Adaptation in Buffer-Aided Full-Duplex Relay Networks with Statistical CSI

In networks with multiple wireless nodes and especially in fast changing environments, the continuous acquisition of Channel State Information (CSI) may become infeasible. In this paper, we study the relay selection problem for a cooperative network, where Full-Duplex (FD) relays are equipped with buffers and only statistical CSI is available at the transmitters (CSIT). For this setting, a novel relay selection algorithm is proposed, named HyQoS, relying only on statistical CSIT and performing power adaptation. HyQoS solves an optimization problem for selecting the optimal set of relays. We consider two optimization approaches: 1) minimization of the total power consumed in the network, and 2) maximization of the throughput per energy unit, while guaranteeing a specific Quality of Service (QoS), in terms of Successful Transmission Probability (STP). The power allocation problem is formulated as a nonlinear optimization one, taking into account inter-relay interference and residual loop interference. Numerical results show that HyQoS can reduce the power expenditure and increase the throughput, by using only statistical CSIT.