已知位置及移動性的媒介收發控制層通訊協定

Abstract

近年來，在各種領域中開始研究關於結合方向性天線的行動通訊設備，方向性天線的使用可以大大的減少無線電的干擾影響，因此無線媒介的使用率可以獲得明顯地改善，其中，方向性天線的技術在「媒介收發控制」(Medium Access Control, MAC)層上的通訊協定已經足夠成熟，在這篇論文中，我們將提出應用在隨意行動無線網路(Mobile Ad Hoc NETwork, MANET)上的「已知位置及移動性的媒介收發控制層通訊協定」(Location and Mobility Aware Medium Access Control layer protocol, LMA MAC layer protocol)，藉由預測行動通訊裝置的位置可以增強在使用方向性天線時，行動節點(Mobile Node, MN)與行動節點之間的通訊聯結強度，另外，在我們提出的通訊協定中將使用方向性探測來減緩方向性天線常出現的遮蔽問題，當所有的節點是根據隨意移動的特性來移動時，空間的使用率以及尋找路由的效率將由我們所提出的「已知位置及移動性的媒介收發控制層通訊協定」提供改善，除此之外，我們加入了方向性信標的控制封包，來確保某個節點改變移動方向或是移動速度後，其他節點們可以擁有正確的位置以及移動性資訊，最後，我們所提出的通訊協定將使用模擬的結果來評估與其他通訊協定的整體表現。

In recent years, the incorporation of the directional antennas within mobile devices has been studied in many areas. The usage of directional antennas can greatly reduce the radio interference, which results in improved utilization of the wireless medium. It becomes practical to exploit the directional antennas in the Medium Access Control (MAC) protocol design. In this paper, a Location and Mobility Aware (LMA) MAC protocol is developed for the mobile ad hoc networks. The predictive location of the mobile devices are adopted to enhance the robustness of the communication linkages while using the directional beams. The deafness problem is also alleviated using the directional listen (D-Listen) mechanism in the proposed algorithm. Under dynamic moving scenarios, both the spatial reuse and the routing efficiency are preserved using the proposed LMA MAC scheme. Moreover, the usage of the control packet named directional beacon can ensure other mobile nodes to have the correct position and mobility information after one node has changed its moving direction or moving velocity. Finally, the performance of the proposed algorithm is evaluated and compared with other existing protocols in simulations.