Fnergy-Fifficient Resource Allocation in Cooperative OFDMA Systems

In this work we study framed transmission in an OFDMA based relayed wireless access system that utilize cooperative diversity. We consider a system of a source, a relay and a number of destination nodes, where the nodes can combine the signals coming from the source and relay. We are interested in the case that the source and relay only have the information of path loss and slow fading. The goal in resource allocation is to allocate resources (time slots, subchannels and power) in an energy efficient manner given target rates and target outage probability. Numerical results show that cooperative relaying requires significantly less energy than noncooperative relaying. Adjusting the source and relay transmission durations has a marginal effect on the performance, although it results in a significant increase in complexity.