An Efficient Location Tracking Algorithm for MANET using Directional Antennas

摘要

In order to implement effective Directional Medium Access Control (DMAC) protocol and routing protocol in Mobile Ad Hoc Networks (MANET), each node in the network should know how to set its transmission direction to transmit a packet to its neighbors. So, it becomes imperative to have a mechanism at each node to track the locations of its neighbors under mobility condition. In this paper, an efficient location tracking algorithm for MANET using directional antennas with fixed beams is proposed to maintain communication between two communicating nodes. The proposed algorithm works in conjunction with the DMAC protocol. The transmitting node will monitor its received power level from the neighboring node's acknowledgement packet transmission. If the received power falls below the threshold, the node indicates the need to switch the antenna element to its data link layer. The DMAC protocol in the data link layer will switch the transmitting antenna either in the clockwise or anticlockwise direction of the active antenna and check for the induced power. Whichever antenna has picked up the signal with sufficient signal strength, handoff takes place from the active antenna to the new antenna. We have shown through simulations, that the mechanism is suitable in highly mobile scenarios. The throughput falls regularly as nodes lose their connection without location tracking. But, the throughput remains a constant or there is a slight dip at the switching time interval when the location tracking is implemented with DMAC.