基于跨层设计的机械振动WSNs同步采集多跳累积误差控制方法

Control of accumulated multi-hop synchronous acquisition error based on the cross-layer design of machine vibration WSNs

针对机械振动无线传感器网络跨层同步采集精度随网络深度增加而急剧降低的问题,建立同步采集关键同步信息传输模型,分析多跳同步误差累积机理,得出嵌入式软件调度实时性不高、晶振随机抖动及无线链路随机迟滞是多跳误差累积主要原因。由此提出基于跨层设计的机械振动无线传感器网络同步采集多跳累积误差控制方法:提出多路硬件跨层设计消除嵌入式软件调度迟滞影响,提高同步任务实时性;采用高精度有源晶振抑制晶振随机抖动;建立无线链路跨层传输随机迟滞数学模型,采用回归分析方法校准由此导致的同步信息随机抖动及传输时延计算误差,提升同步采集精度。最后组建4跳网络进行同步采集对比试验,实验结果表明多跳累积误差得到有效抑制。

Aimed at the problem that the error of synchronous acquisition method based on a cross-layer design would accumulate rapidly with network expansion,a transmission model for synchronous information was established,and its mechanism was analysed.It is found that the low real-time performance of embedded systems,the random jitter of crystal oscillator and the delay jitter of wireless link are the main reasons of error accumulation.Thus,a control method for the accumulated synchronous error based on the cross-layer design was proposed and a multipath cross-layer design was provided to capture synchronous information and trigger timer.A high accuracy crystal oscillator was adopted to suppress the jitter;The mathematical model for the random delay of wireless link was established,and the regression analysis was adopted to calibrate the caused errors such as the random jitter of synchronous information and the calculation error of transmission delay.Finally,a 4-hop network was constructed to evaluate the proposed method,which shows that the accumulated error is suppressed effectively.