Practical issues on resource optimization for relay networks

Optimum resource allocation is essential for wireless cooperative networks. Instead of limiting to energy optimization, we recently investigated the two-dimensional energy and location optimization with arbitrary number of relays, and in the presence of possible direct source-destination link. In this paper, we consider several practical issues in such a 2-D optimization. These issues include the relative benefits of energy and/or relay location optimization under various scenarios, and the selection of desirable relays in a two-dimensional plane for given system parameters and requirements. Extensive analysis and numerical plots reveal that the optimization gain varies considerably at different relay location and/or with different energy allocation. Interestingly, our study on relay selection shows that the the relays sitting on the source-destination line do not always outperform the ones sitting off the line.