摘要：
In multi-monitoring-task mobile sensor networks,different monitored objects have different requirements for real-time transmission.To satisfy those requirements,a multi-layered real-time data routing protocol (MRDR) was proposed to satisfy the requirements of both soft real-time and hard real-time monitoring.In MRDR,a layer mechanism was introduced into mobile sensor networks and the network was divided into layers with equal width.For ordinary event messages with higher delay tolerance,MRDR could enable messages to be forwarded to the sink at as low energy consumption as possible.For emergent event messages with lower delay tolerance,MRDR could send messages to the sink by multi-hop real-time transmission.At the same time,for the problem of energy holes in hard real-time routing,a backward mechanism was proposed to enable emergent event messages avoiding node holes and finally be transmitted to the sink.At last,to reduce message redundancy,message queue management was designed and the principle for discarding messages was presented when the queue was full.To evaluate the performance,simulation was carried out to compare MRDR and other three algorithms in terms of network lifetime,average delivery ratio and average delay.The result proved the efficiency of MRDR.In different network environments,MRDR could effectively be applied to multi-monitoring-task mobile sensor networks and satisfy different requirements of different real-time transmissions.%在多監控任務移動傳感器網絡中,不同的監控對象對數據傳輸實時性有著不同的要求.為滿足監控數據不同的實時性要求,提出了既能滿足軟實時監控要求,也能滿足硬實時監控要求的多級分層實時數據路由協議MRDR (layer-based multilevel real-time data routing protocol).MRDR協議將分層機制引入移動傳感器網絡,將網絡分成寬度相等的若干圓環.對具有實時性要求更低的普通事件消息,MRDR在消息失效前以盡量低的能耗將消息轉發至sink節點.對于實時性要求更高的緊急事件消息,MRDR讓消息以層間多跳方式實時傳輸到sink.同時,針對硬實時路由過程中的節點空洞問題,提出了消息回傳機制,使得緊急事件消息能繞過節點空洞并最終傳輸至sink.最后,為降低網絡中的消息冗余,設計了消息隊列管理機制,給出了隊列滿時的消息丟棄原則.為評價算法性能,仿真實驗對比了MRDR與其他3種算法在網絡壽命、數據傳輸成功率與消息平均延遲方面的表現,結果驗證了算法的有效性.在不同的網絡環境下,MRDR算法能有效適應多監控任務移動傳感器網絡,滿足具有不同實時性要求的不同消息的傳輸要求.
