Improving Throughput by Link Distance Control in a Multi-Rate Ad Hoc Network
Xiaoxin Wu, Gang Ding, Bharat Bhargava, Shan Lei · Purdue e-Pubs (Purdue University System) · 2004
Multi-modulation-mode mobile devices can transmit or receive data at different rates.Link adaptation is widely used for improving thl-oughput.through which link layer chooses the data rate based on signalto-noise ratio (SNR).In most routing protocols for ad hoc networks, the route with the minimum hop count will be selected.The end-to-end data rate can be low since the small hop number implies the large geographic distance (link distniice) between nodes.The SNR at the receiving node is low due to the large radio signal attenuation.which results in low data rate.On the other hand, making routes with large number of hops means more nodes will contend for the channel.This will reduce the channel occupation time for each node and decrease the end-to-end throughput.In this work, analysis shows that changing link distance affects the saturated throughput.and an optimal link distance exists so that the highest network end-to-end throughput can be achieved.Based on this observation, an Adaptive-Searching-Range Routing Protocol (ASRP) is proposed, in which the searching range for next hop is adaptive according to the network load.so as to get better network throughput.Link layer and routing layer protocol issues are addressed.Simulation results show that ASRP can improve network end-to-end delivery ratio.