A Latency-Energy Trade-off MAC Protocol for Wireless Sensor Networks

這篇論文將介紹應用於無線感測網路上之Latency MAC (LMAC)。 在文章之中，我們將探討造成無線感測網路浪費之各種因素，並藉由犧牲多餘的封包延遲時間來避免最大的能源浪費： 閒置接收。 我們將檢視無線感測網路的封包延遲時間需求，接著研究再節省能源與封包延遲時間中的折衷方案。 在這尋求折衷的過程之中，我們會遇到許多限制，因此，我們也必須一併研究及分析這些額外的限制因素，在這條件下設法達到一最佳的節省能源與封包延遲時間的折衷。 藉由提升猜測資料封包的產生、傳輸時間預測，我們可以在模擬結果上發現LMAC確實消耗了較少的能源，尤其是在一個鬆散封包延遲時間或是較低網路傳輸的無線網路下。This paper proposes Latency MAC (LMAC) protocol for wireless sensor networks. We investigate the idle listening problem and try to avoid it by sacrificing latency. We examine the latency constrain in wireless sensor networks and study the tradeoff between extra latency and energy-efficiency. In the process of trading latency for energy-efficiency, there are many restrictions. Thus, we study and analyze these limitations and then try to achieve the best tradeoff between latency and energy-efficiency under these limitations. By increasing the arrival prediction accuracy of data packets, the simulation results show that LMAC indeed consumes less energy, especially under a loose latency constrain or a light traffic load in wireless sensor network environments.Acknowledgement ii要 iiiBSTRACT ivIST OF FIGURES viiIST OF FORMULA AND TABLE viiiNTRODUCTION 1.1 Motivation 2.2 Energy-Efficiency Problems in Wireless Sensor Networks 3.3 Thesis Organization 5ELATED WORK 6.1 Energy-Efficiency MAC Protocols in Wireless Sensor Network 6.2 Latency Related Work 9ATENCY MAC 11.1 Overview of Latency MAC 11.2 Time Synchronization 14.3 Details of Sleep Schedule in LMAC 15.3.1 Bulk and Doze Parameters 15.3.2 Transmission Rate Constrain 15.3.3 Buffer Overflow Constrain 16.3.4 Latency Constrain 16.3.5 Initial Scheduling 18.4 Optimization 19.5 Traffic Adaptation 20IMULATIONS 21.1 Simulation Tool: NS2 21.2 Simulation Setup 21.3 Simulation Result 22ONCLUSION AND FUTURE WORK 29EFERENCE 31PPENDIX 3