優化無線通訊品質之群體移動演算法設計

Abstract

一個移動式無線感測網路乃是整合了大量移動式感測點與無線網路所形成之環境監控或探索系統，而在這樣的整合型系統中，如何有效的協調無線通訊、感測、和移動等機制就成了一個很重要的課題。 當移動式無線感測網路在執行一個環境監控任務時，如果每一個感測點都以同樣的速率傳送感測到的資料回基地台，則替比較多感測點做繞徑的感測點，將很容易發生資料擁塞的問題，且當在特定的區域有事件發生而需要傳送大量的資料時，整個網路的使用效率將大幅度降低，這樣的問題也許可以透過改變網路的架構或通訊協定的方式來改善，但效果十分有限。 本論文，提出了一個以分散式架構為主的移動演算法，此演算法的目的在於如何根據每一個感測點需要的傳輸量，有效的分配通道傳輸容量，而因為兩個無線傳輸端點的通道傳輸容量與距離大約是呈現一個反比的關係，此演算法便根據此一關係，以設計人工作用力的方式讓每個感測點移動到最適合的位置，同時平均地分散整個網路感測點數目的密度，並且增加其總感測涵蓋區域。 此論文最後利用MATLAB軟體做模擬，並根據模擬的結果，包括平均值、標準差、涵蓋區域範圍和收斂度評估此演算法的效能和穩定度。

A mobile wireless sensor network (MWSN) is the combination of a large number of mobile sensor nodes and a wireless network. An effective coordination of communicaiton, sensing and moving is an important issue in an MWSN. When a MWSN is processing a moritoring task, it is assumed that every node transmit the sensing data to a base station in the same rate. Then, the network will easily make a congestion problem at the node routing for larger data. In addtion, if there is a event occurred at some specialized area, the usage of whole network will be largely decrease. This problem may can be overcame by the adjustment of network architecture or protocol, but the effect is limited. This paper proposes a distributed moving algorithm for redeploying these mobile sensor nodes. The functional goal of this algorithm is to adaptively allocate the channel capacity based on the amount of the sensing rate at each node, as well as to dynamically spread these nodes for increasing the coverage area and related utility. A simulation platform using MATLAB is also presented, and related statistical results including mean, standard deviation, coverage and convergence are used to illustrate the performance of the proposed algorithm.