SNR-Based OLSR Routing Protocol for Wireless Mesh Networks

Wireless Mesh Networks (WMNs) consist of a collection of mobile and fixed nodes that form a network. Nodes are capable of communicating with each other either with infrastructure, or infrastructureless, or in a hybrid mode. The major advantages of WMNs over the other wireless networks are the low-cost, self organization, self configuration, last mile internet solution, scalability, and reliability. These advantages have attracted the researcher over the last five years. WMNs technology is gaining an increased attention from the Institute of Electrical and Electronics Engineers (IEEE) community. This led the IEEE organization to emerge a special working group (IEEE 802.11s) in charge of the issues deriving from a completely wireless distribution system used to interconnect different Basic Service Sets (BSSs) through secure and performing links. In a multi-hop networks, like WMN, one of the main factors that influences the performance is the routing protocol. Generally speaking, routing protocols can be classified based-on the routing metric to 1) hop count-based routing protocols, like Adhoc on demand distance vector (AODV) where the optimum path is defined as the path that goes through the minimum number of nodes, 2) the link quality-based routing protocols, like OLSR where some metrics such as the bandwidth and the packet error rate are considered to define the optimum path to the destination. In this work the performances of a three commonly used routing protocols are compared. The main goal of this stag is to study the influence of different routing protocols in WMNs. The comparison is conducted with two scenarios of networks; a high mobility network and a low mobility network. (Open network) OPNET 11.5 modeler is used to build the WMNs. The performance of the network and the routing protocols has been studied in means of network throughput, End-to-End delay, routing protocol overhead and the mobility. The obtained results show that the Optimized link state routing protocol (OLSR) has the highestthroughput overDSR andAODVrouting protocols in WMNs. The unpredictable behavior of the wireless medium in WMNs environment demands the need for a routing protocol that is aware of the link conditions. Unfortunately the routing protocols used such as AODV and Dynamic source routing (DSR) are hop count-based; where the routing algorithm uses the number of nodes to determine the optimum path to the destination. In the second stage of this work a new routing technique for WMNs based-on Signal to noise ratio (SNR) as a new metric for OLSR routing protocol, is developed. The new metric has been implemented on the OLSR routing protocol module using OPNET simulator. The modified OLSR routing protocol is implemented in the comparison scenarios. The obtained results show that, when SNR is used as a routing metric in the OLSR routing protocol, the OLSR is getting the significantly higher network throughput over the DSR and AODV routing protocols. In the same time, the modified OLSR implemented with the SNR metric is showing a high improvement over the OLSR with the traditional hop-count metric. This thesis also studies the affect of different amounts of mobility in WMNs performance. VI