Area Spectral Efficiency of Cooperative Network with Opportunistic Relaying
In this paper, we investigate the area spectral efficiency (ASE) in a three-node cooperative network with opportunistic relaying. On one hand, in conventional cellular network, ASE is defined to be the average data rate per unit bandwidth per unit area supported by a base station. On the other hand, in cooperative network, since there is no such a central base station, we redefine ASE to be the average data rate per unit bandwidth within a particular area, in which simultaneous transmissions are not allowed. In addition, to maximize the instantaneous capacity between the source and the destination, we apply a transmission mode selection criterion to determine whether the direct transmission or the multi-hop relay transmission is utilized. We derive the mathematical expression of ASE with the consideration of the relay node location and the impact of path-loss and fading effects. We show through selected numerical examples the effect of relay node position on the performance metric of ASE.