Joint energy and location optimization for relay networks with differential modulation

The optimum resource allocation in communication systems is critical to enhance their performance and efficiency. In wireless networks relay transmissions can enable cooperative diversity by forming virtual antenna arrays. In this paper, we consider resource allocation which minimizes the average system error rate not only by the power optimization, but also by the location optimization for systems with arbitrary number of relays. Differential modulation which bypasses the channel estimation at the receiver is investigated using the decode-and-forward protocol. Analytical and simulated comparisons confirm that the optimized systems provide considerable improvement over un-optimized ones, and that the minimum error rate can be achieved via joint energy-location optimization.