Distributed quality-of-service routing in ad hoc networks

摘要

In an ad hoc network, all communication is done over wirelessnmedia, typically by radio through the air, without the help of wirednbase stations. Since direct communication is allowed only betweennadjacent nodes, distant nodes communicate over multiple hops. Thenquality-of-service (QoS) routing in an ad hoc network is difficultnbecause the network topology may change constantly, and the availablenstate information for routing is inherently imprecise. In this paper, wenpropose a distributed QoS routing scheme that selects a network pathnwith sufficient resources to satisfy a certain delay (or bandwidth)nrequirement in a dynamic multihop mobile environment. The proposednalgorithms work with imprecise state information. Multiple paths arensearched in parallel to find the most qualified one. Fault-tolerancentechniques are brought in for the maintenance of the routing paths whennthe nodes move, join, or leave the network. Our algorithms consider notnonly the QoS requirement, but also the cost optimality of the routingnpath to improve the overall network performance. Extensive simulationsnshow that high call admission ratio and low-cost paths are achieved withnmodest routing overhead. The algorithms can tolerate a high degree ofninformation imprecision