| Summary: | 碩士 === 國立臺灣科技大學 === 資訊工程系 === 93 === The flexibility, self-organization and multihop transmissions of MANET are well suited to extending service area of gateway (or access point) in infrastructure-based networks. The research area about integration of MANET and infrastructure-based networks becomes popular. In such environment, commonly known as wireless access networks or hybrid ad hoc networks, mobile hosts outside the transmission range of the gateway can communicate with the gateway via multihop transmission. On-demanding routing protocol like AODV has been used for routing between gateway and mobile hosts because of their low routing overhead. However, routing path between them tends to detour. It means that packet transmits along longer path instead of shortest one. In addition, mobile hosts discover routes about gateway via a flooding technique inducing another kind routing overhead.
In this thesis, we present a novel extension of the AODV routing protocol. To avoid phenomena of detour resulted from route maintenance, we modify the rule of route update in AODV. The basic idea of our mechanism is to consider both destination sequence number and hop count to prevent a valid path from being updated to a longer path. Besides, to limit route request scope, we uses hop count which represents number of hops to reach destination to guide our route request message toward gateway. It can help for eliminating route message dissemination toward unnecessary areas. In the end, several simulations are made to validate the performance of our mechanism and compare with previous methods.
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