Cross-layer resource allocation of two-way relaying for statistical delay-QoS guarantees

In this paper, we consider the cross-layer design for delay quality-of-service (QoS) provisioning in two-way relay systems. We aim to find the optimal resource allocation policy to maximize the weighted sum-rate while guaranteeing the statistical delay-QoS requirements for both users. The delay requirement is characterized as the QoS exponent. With the integration of the concept of effective capacity, the cross-layer optimization problem is equivalent to a weighted sum effective capacity maximization problem. We derive the optimal joint power and rate adaptation policy for the two-phase two-way relaying. Numerical results show that the proposed policy can efficiently support diverse QoS requirements and significantly improve the performance compared with both the fixed power scheme and the weight-based method.