Extending Network Knowledge: Making OLSR a Quality of Service Conducive Protocol
EION paper accepted for presentation at the International Wireless Communications and Mobile Computing Conference
July 3-6, 2006
Finding and maintaining paths in wireless ad hoc networks is not trivial due to node mobility and variable environmental conditions. Robust and efficient routing algorithms are required. OLSR is a link state proactive routing algorithm for ad hoc networks that makes use of an optimized mechanism, based on Multipoint Relays (MPRs), to perform broadcasting and path computation. OLSR only makes use of its partial view of the network topology along with the Minimum Hop Count (MHC) metric to construct routing paths, therefore, it suffers from a lack of knowledge, such as full topology knowledge, nodes and links status (e.g. remaining battery, link quality) and network load in order to make better routing decisions. Also, MHC paths are usually constructed by longer links, which tend to provide lower throughput and frequent breakage. In this research the network knowledge available for OLSR is extended by gradually increasing its partial network topology view. Several TC_ redundancy strategies are combined with the MPR_Coverage feature of OLSR while maintaining its optimal broadcasting mechanism. NS-2 simulation results show the costs and benefits in terms of communication overhead and increased topology knowledge, respectively, to make OLSR a robust and QoS-conducive routing protocol.
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