Cooperative Relaying with Feedback for Lifetime Maximization

This paper investigates new transmission protocols that maximize the lifetime of a network under a Quality-of- Service (QoS) constraint. The proposed schemes incorporate a Decode-and-Forward relaying strategy with an instantaneous channel feedback in order to save energy and therefore prolong the network lifetime. Based on a combination of the required average transmitted power that supports the target QoS constraint with feedback of the measured power, an intelligent switching between direct transmission, relaying transmission and transmission postponement is proposed. The lifetime of the network is determined by using a simple probabilistic model that is validated via theoretical and numerical studies and is suitable for practical applications. We show that the proposed techniques significantly increase the lifetime of the network without affecting the considered QoS and delay constraints and seem to be promising solutions for "Green Radio" technology.