在無線行動隨建即連網路 (wireless mobile ad hoc networks)上，行動主機要互相通訊，常常使用廣播機制。但是過去的氾洪法廣播機制，會導致嚴重的重複、競爭和碰撞。在每次廣播時，每個主機都必須耗損傳輸與接收的電量，這對於電量受到限制的行動配備來說一大負擔，如果行動主機因此而快速的耗盡電量，將造成網路的不穩定。因此本論文設計幾個平衡電量廣播演算法，希望網路上的高電量行動主機能夠進行重播 (rebroadcasting) 的動作，而低電量的行動主機則減少重播的次數，藉此平衡網路上主機的剩餘電量。行動主機利用剩餘電量，以及鄰居剩餘電量及個數，來決定重播機率，主機剩餘電量越多，則重播的機率越高。模擬結果顯示，使用我們的電量平衡演算法，可以有效平衡網路上行動主機的電量，大幅減少主機剩餘電量的標準差，並延長網路的存活時間。 Broadcasting is an important operation in a mobile ad hoc network (MANET). A straightforward approach to perform broadcast is by flooding. Unfortunately, flooding will cause some problems such as redundancy, contention, and collision. The Power-consuming features of flooding will lead to rapid battery exhaustion which will cause network unreliable. Hence, how to balancing remaining power of mobile hosts is a critical issue for a MANET. Our proposed power balance broadcast algorithms incorporate the residual battery energy of hosts into rebroadcast criterion. Each host rebroadcasts with a rebroadcasting probability, which is dynamically calculated by hosts’ residual power, number of neighbors, and average residual power of neighbors. Hence, low-power hosts broadcast with lower probability and high-power hosts broadcast with higher probability. We inhibit low-power hosts from frequently rebroadcasting to balance the remaining power of hosts and extend the lifetime of the network. According to the simulation results, power balance broadcast algorithms compared with the flooding approach can increase network lifetime by around 40%, reduce the standard deviation by 35%, and save a half of rebroadcasting. Our approach can balance the remaining power of hosts with high reachability, even in high mobility environments.
