無線多媒體感測網路下之高效能叢集式多通道媒介存取控制協定設計

Abstract

在無線感測網路中使用多媒體感測節點可以大幅提升對事件的描述能力。因此，針對無線多媒體感測網路的研究日漸普及。傳送多媒體資料，如影像或影音會有較大的資料量，所以在無線感測網路中利用低能量節點要有效地傳送多媒體資料需要更大的頻寬支援。在本論文中，我們提出一個在無線多媒體感測網路下之高效能叢集式多通道媒介存取控制協定設計(EMC-MAC)來達到高產量，低媒介存取延遲時間，以及高節能的目標。我們的方法整合了分時多工存取與載波感測多重存取兼碰撞避免協定的優點，以達到讓節點有效地運用所分配到的頻道與時槽。EMC-MAC也運用一個有效的節能機制來減少需要傳送資料給叢集首的節點數量，以及利用滑動競爭窗來有效地使用控制頻道。模擬結果顯示，EMC-MAC的產量比COM-MAC高出23.72%，平均媒介存取延遲時間比COM-MAC低44.59%，以及第一個節點能源耗盡的回合數可以比COM-MAC多72.24%。

Using multimedia sensor nodes in wireless sensor networks (WSNs) can largely improve the capability of WSNs for event description. Thus, the research on wireless multimedia sensor networks (WMSNs) becomes much more popular recently. Since transmitting multimedia contents, such as video or audio clips, involves a large amount of data, WMSNs need large bandwidth to deliver multimedia contents effectively using energy-constrained sensor nodes. In this thesis, we propose an efficient multi-channel medium access control (EMC-MAC) protocol for cluster-based WMSNs to achieve high throughput, low medium access delay and high energy efficiency. Our proposed EMC-MAC integrates the benefits of TDMA and CSMA/CA to effectively utilize channels and timeslots assigned to sensor nodes. It also uses an energy efficient mechanism to reduce the number of nodes needed to send data to the cluster head and uses a sliding contention window to effectively utilize control channels. Simulation results show that the proposed EMC-MAC’s throughput is 23.72% higher than COM-MAC, its average medium access delay is 44.59% lower than COM-MAC, and the rounds till the first node death is 72.24% longer than COM-MAC. With the low medium access delay feature, our protocol is feasible for applications of real time multimedia traffic sensing and transmitting, such as remote monitoring of hospital patients and fire spots.