無線感測器網路(Wireless Sensor Networks, WSNs)是由大量的感測器節點(Sensor Nodes)所組成的網路，可以讓使用者藉由將個別不同節點所傳送之資料加以結合來達到準確地監控遠端環境的目的。所以這樣的網路需要能提供有能源效率(Energy-Efficient)和較小延遲(Lower Latency)的通訊協定。因此，為了延長感測器節點的生命週期，設計ㄧ個有效率的路由協定是相當重要的。目前已經有很多方法，像是直接通訊(Direct Communication)、平坦式泛播(Flat Flooding)、叢集式協定(Clustering Protocol)等，都已經被提出並用來在隨意散佈的感測器節點上傳遞資料。
本篇論文提出一個階層式多重選擇路由路徑協定(Hierarchical Multiple-Choice Routing Path Protocol, HMRP)，這個路由協定經由多重路徑、能源平均、以及資料聚集的方式收集資料，來達到對於系統生命週期和資料成功傳送率有比較好的效能。在設計這個協定時，主要是以滿足無線感測器網路中感測器節點將感應到的資料自發的傳回給資料收集中心(Sink)的需求為目標。所以我們以資料收集中心為樹根，藉由發送自身的節點值(Hop Value)來找出子節點，每一個感測器節點都利用同樣的方式找出自己的子節點。在HMRP中每個節點使用候選資訊表格(Candidates Information Table)紀錄相關父親節點，避免要週期性的以泛播的方式來達成資訊更新。此外，這個樹狀的結構將會在有節點失效或是加入新節點時自動的重新配置(Reconfigure)。由模擬實驗的結果顯示，HMRP可以比一般提出的多點(Multi-hop)叢集式或樹狀基礎的方法更有效率的增加系統生命週期和資料成功傳輸率。 The wireless sensor networks (WSNs), a network comprising the huge number of sensor nodes, allow users to monitor a remote environment accurately by combining the data intelligently from the individual nodes. These networks require robust wireless communication protocols that are energy-efficient and provide lower latency. Therefore, in order to prolong the lifetime of the sensor nodes, designing efficient routing protocols is critical. Several approaches, including direct communication, flat, and clustering protocols, have been proposed to transmit data in randomly deployed sensor nodes.
In this thesis, we present a Hierarchical Multiple-Choice Routing Path Protocol (HMRP), a routing protocol for collecting data over multi-path, energy-balancing, and data aggregation to achieve good performance in terms of system lifetime and data delivery ratio. The design of the protocol aims to satisfy the requirements of sensor networks that every sensor transmits sensed data to the sink spontaneously. The sink constructs hierarchical tree by broadcasting its hop value to find the child nodes. Other nodes discover the child nodes in turn by the same way. The HMRP uses Candidates Information Table to avoid flooding and periodic updating of routing information. Moreover, the tree will automatically reconfigure according to nodes failure or adding the new nodes. The simulation results show that HMRP can increase the system lifetime and data delivery ratio by comparing with other general-purpose multi-hop clustering or tree-based approaches.
