Cross-layer Resource Allocation Strategies for Quality-of-Service Driven Opportunistic Routing Over Wireless Relay Networks

We develop a cross-layer optimization framework incorporating opportunistic routing and quality-of service (QoS) driven power allocation. By applying opportunistic routing, we optimally select one relay for each source-destination pair to assist their transmissions. By integrating information theory with the concept of effective capacity, our strategies aim at maximizing the relay network throughput subject to a given delay QoS constraint. We first propose two resource allocation strategies for the QoS driven opportunistic routing, under two different instantaneous power constraints. In the first strategy, we set the instantaneous constraint on the total transmission power of the wireless relay networks; while in the second one, we set the power constraint on each source-destination pair. In addition, we introduce another resource allocation strategy with the average power constraint of each source-destination pair. The simulation results show that the first two strategies have nearly the same effective capacity performance, and that the third strategy outperforms the first two strategies only when the QoS requirement is stringent.