On Performance of Cooperative Communication Systems with Spatial Random Relays

Cooperative communications can significantly enhance the performance of wireless systems by exploiting the inherent spatial diversity gains. In this work, a decode-and-forward cooperative cellular system with spatial random users is investigated. Under a realistic channel model including path loss, shadowing and multipath fading, the users are selected as relays depending on their instantaneous SNR so that error propagation caused by detection errors at the relays can be mitigated. The locations of users are modeled as random point processes. Based on the theory of point processes, an analytic approach to system performance is developed to accommodate the random location of users as well as the underlying channel. The locations of the selected relays are investigated and the outage performance averaging over all possible user locations is analyzed. The accuracy of the analytical results is verified by Monte-Carlo simulations. Various issues, such as power allocation, are also investigated using the numerical results.