An Adaptive Cross-Layer Design for Prioritized Traffic in Wireless Communications

Duty cycles have been widely studied recently to reduce the energy consumption for wireless communications. Although duty cycles can effectively reduce energy consumption, they may also increase the packet delay as the packets can only be forwarded when the next hop is awake. The mechanism is hence not suitable for delivering urgent messages. In this paper, we propose an adaptive cross-layer design for delivering prioritized traffic in wireless communications. Our cross-layer design integrates a modified X-MAC protocol with our generalized Random Re-Routing protocol coherently. Duty cycles will be applied if there is only ordinary traffic in the network. When high priority data are present, duty cycles will be disabled and priority routing will be employed. We generalize the QoS-aware Random Re-Routing protocol to support data with multiple priority levels. Different routing policies and transmission power will be selected according to the priority levels of the data packets. Extensive simulations have been conducted in OMNET++ to evaluate the performance of our system. The results demonstrate that our design can achieve both satisfactory packet delay and energy consumption.