Fairness‐adjustable opportunistic relay selection in the power‐constrained cooperative networks with adaptive transmission

Abstract

The existing literatures have not considered either the fair power consumption in multi-user cooperative networks or the fairness-adjustable relay selection scheme. The authors propose a fairness-adjustable opportunistic relay selection in the multi-user dual-hop decode-and-forward cooperative networks with the optimal simultaneous power and rate adaptation under realistic power constraints, where the selection result is determined by the instantaneous signal-to-noise ratios over the relay links, the power load (PL) of the relays and the weight factor. The weight factor, also behaving as the metric of fairness, is introduced to adjust the bias between the average channel capacity for the relaying user and the fair PL distribution and is obtained by the proposed capacity-fairness bias criterion for the required fairness target. The average channel capacity has been derived approximately for the proposed scheme and the numerical results underscore the significant benefits of jointly exploiting the channel capacity and fairness.