On Power Control with Finite Rate Feedback for Cooperative Relay Networks

Power control strategies with finite rate feedback are studied for the cooperative channel. The main contribution of this paper is to show that quantized feedback information can lead to significant reduction in outage probability for the cooperative relay network. To obtain an increase in diversity order and significant reductions in outage probability over constant power cooperative signaling, we develop algorithms that exploit the channel states of all network links. With one feedback bit, the proposed power control algorithm is shown to double the diversity order of constant power transmission. To quantify the performance increase of using power control in the cooperative network, we derive a lower bound on the diversity order. Based on these results, it is evident that future network protocols should utilize feedback in order to exploit the potential gains of network coding.