Opportunistic Cooperation for Quality of Service Provisionings Over Wireless Relay Networks

We propose the QoS-driven opportunistic cooperation schemes for the wireless relay networks. By integrating information theory with the concept of effective capacity, our schemes aim at maximizing the relay network throughput subject to a given delay QoS constraint. Applying the time division multiple access (TDMA) and frequency division multiple access (FDMA) techniques to the relay networks, we derive a set of optimal static and dynamic time/bandwidth allocation strategies under either constant or dynamic power control. When the power allocation is constant, we prove that the FDMA based schemes outperform the TDMA based schemes. On the other hand, when the power allocation is dynamically adjusted, we observe that the TDMA based schemes offer the same effective-capacity performance as the FDMA based schemes. We also analytically characterize the impact of the wireless-relay-network topologies and QoS requirements on the effective-capacity performances of our proposed strategies. The extensive simulation experiments show that our proposed strategies significantly outperform the existing equal-time or equal-bandwidth allocation strategies in terms of the effective capacity.