實作XD: 致力於高效率之無線感測網路資料傳輸機制

Abstract

這篇論文著眼於實作出無線感測網路中的一種資料傳輸機制─Cross-layer Diffusion (XD)，其設計理念為及時且可靠的傳送資料，以用於重要任務如老人護理中心的定位追蹤系統。XD結合了MD以及混和CSMA和TDMA的機制。MD是一種隨機重覆傳送資料的路由協定，其建立的拓撲資訊亦同時被XD中的TDMA所使用。以前的模擬結果宣稱XD比MD效能更好。而就我們所知，這篇論文是第一個將XD實做出來的研究。但結果顯示，不管我們使用和以前模擬一樣的設定或實際應用的環境像是定位系統，在絕大部份的情況下MD的效能都比XD好。這是由於在XD的模擬中使用了不切實際的小TDMA時槽寬度，導致預期的XD網路傳輸容量比實際來得大，高估了XD的效能。

This paper focuses on implementing a data dissemination mechanism of wireless sensor network (WSN) - Cross-layer Diffusion (XD), which aims at providing timely and reliable data transmission for mission critical applications such as location tracking system in elderly care centers. XD is a combination of MD, an opportunistic redundant data transmission routing protocol, and hybrid CSMA and TDMA which utilizes topology information established by MD. Prior work claims that XD is better than MD based on the results of simulation, and this paper is the first that XD is successfully implemented. Based on the evaluation of XD and MD on BL-live testbed with settings in simulation and in real applications such as location system, we conclude that MD is better than XD in general due to impracticably small TDMA slot width used in simulation which determines the network capacity of XD.