Distributive Delay-Sensitive Cross-Layer Design for OFDMA Systems

Delay-sensitive cross-layer design has recently attracted increasing interests in providing delay performance guarantee and exploiting multi-user diversity throughput advantage for real-time traffic. However, existing cross-layer designs usually require centralized scheduling and information gathering, including full channel state information (CSI) and delay requirements, to exploit multiuser diversity gain as well as QoS (delay) provisioning. In this work, we provide a novel distributive solution to the delay-sensitive cross-layer OFDMA scheduling problem as well as introducing significant saving in the average feedback cost per user compared to classical cross- layer design. Simulation results illustrate that our proposed distributive design achieves the optimal performance as the centralized scheduling with much lower implementation complexity while maintaining heterogeneous users' delay requirements. Effects of CSIT outdateness are also considered in the proposed distributive cross-layer design framework.