An active queue management for wireless sensor networks with priority scheduling strategy

In Wireless Sensor Networks (WSNs), the packet congestion will lead to high delay and high packet loss rate, which severely affects the timely transmission of real-time packets. As a congestion control method, Random Early Detection (RED) is able to stabilize the queue length at a low level. However, it does not classify the data of WSNs to achieve a targeted queue management. Since real-time packets are more urgent and important than non-real-time packets, differential packets scheduling and queue management are necessary. To deal with these problems, we propose an Active Queue Management (AQM) method called Classified Enhanced Random Early Detection (CERED). In CERED, the preemption priority is conferred on real-time packets, and the queue management with enhanced initial drop probability is implemented for non-real-time packets. Next, we develop a preemptive priority M/M/1/C vacation queueing model with queue management to evaluate the proposed method, and the finite-state matrix geometry method is used to solve the stationary distribution of the queueing model. Then we formulate a non-linear integer programming problem for the minimum delay of real-time packets, which subjects to constraints on the steady state and system cost. Finally, a numerical example is given to show the effectiveness of the proposed method.