SUMMARYIn this letter, we reveal redundant control traffic in the optimized link state routing protocol (OLSR) for MANET. Topology control (TC) messages, which occupy a part of control traffic in OLSR, are used to exchange topology information with other nodes. TC messages are generated and forwarded by only nodes that have been selected as multipoint relays (MPRs) by at least one neighbor node. These nodes selected as MPRs are called TC message senders in this letter. One of solutions to reduce the number of TC messages is to reduce the number of TC message senders. We describe a non-distributed algorithm to minimize the number of TC message senders. Through simulation of static-node scenarios, we show 18% to 37% of TC message senders in RFC-based OLSR are redundant. By eliminating redundant TC message senders, the number of TC packets, each of which contains one or more TC messages, is also reduced from 19% to 46%. We also show that high density scenarios have more redundancy than low density scenarios. This observation can help to consider a cooperative MPR selection in OLSR.
Vehicular Ad-hoc Networks (VANETs) are an extension of Mobile Ad-hoc Networks (MANETs). However, many routing protocols of MANETs do not perform very well in VANETs due to their unique characteristics such as moving at high speed and road patterned movement. Thus, routing protocols and the other issues must be adapted to those VANETs characteristics. Moving at high speed causes links to be broken easily, which is not a good situation for real-time applications that need stable and reliable connection. Thus, in order to support those kinds of applications, we introduced probabilistic relay to improve the performance of routing protocols in VANETs.In this paper, we implemented probabilistic relay into OLSR and AODV protocols and compared their performance with the original ones using a computer simulation with realistic scenarios in VANETs. We evaluated those protocols under different metrics such as vehicle mobility and road segment length. We showed that probabilistic relay could provide a significant improvement in routing protocols' performance especially in packet delivery ratio.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.