机载波分复用网络强实时性调度算法设计

Design of Hard Real-Time Scheduling Algorithm in Avionic Wavelength Division Multiplexing Network

与传统的商业网络不同,航空机载波分复用网络要求强实时性以保证消息的传输性能。实时调度算法是保证机载网络中消息传输性能的关键。针对机载波分复用网络的实时性要求,采用实时通信中的周期性任务模型,提出了满足机载波分复用网络实时性要求的加权轮转调度算法,其中轮转周期的选择、权值匹配方法和多信道分配方法是影响调度算法参数设计的重要过程。通过多信道分配方法有效减少了消息拆分次数;结合实例比较确定了算法中消息分配权值的计算方法;并指出了最优轮转周期无法保证最小的消息延迟时间率。研究结果对机载波分复用网络的工程设计与优化有一定的指导意义。

Different from the commercial applications, the avionic wavelength division multiplexing （WDM） network lays much emphasis on hard real-time characteristics. The real-time scheduling algorithm is a key issue to ensure the message transmission performance. According to the real-time communication requirement of avionic WDM network and the traffic characteristics of the avionic network, a weighted round robin scheduling algorithm is proposed based on the periodic task model of real-time communication to guarantee hard real-time transmission in an airborne WDM network, which is comprised of the rotation cycle selection, weights assignment scheme and multi-channel allocation method. Among them, multi-channel allocation method efficiently reduces the splitting times of the message; combined with examples, message weights assignment scheme is determined and it is pointed out that the optimal rotation cycle cannot guarantee the minimum message delay ratio. Research results are meaningful for the design of real-time scheduling parameters and the current practice of avionic WDM network.