在無線隨意網路使用虛擬網格之能源節省機制

Abstract

Power-saving is a critical issue in ad hoc networks since the nodes are energy-limited devices. This paper presents an energy-efficient routing protocol Enhanced Geographical Adaptive Fidelity, EGAF, for ad hoc networks. The EGAF protocol uses the concept of virtual grids, which are based the grid architecture of the geographical adaptive fidelity (GAF) protocol. GAF divides the whole network area into several identical square areas, called virtual grids; in each grid, there is only one node which needs to participate in forwarding packets. EGAF always keeps the nodes which are responsible for network routing near the center of each grid instead of whole area of each grid in GAF; hence the square size in EGAF is more flexible. Under the same transmission range, the square size in EGAF cab be bigger than the one in GAF. In other words, there are fewer squares in EGAF due to the bigger square size; this means that only fewer nodes need to be awake and more nodes can be asleep. Due to the higher ratio of the awake nodes to the asleep nodes, EGAF can improve network lifetime. The simulation results show that EGAF has better performance than GAF does.