Archive for the ‘Research Papers and their synopsis’ Category
In wireless mesh network with only one gateway,if the network is expanding then one gateway node will become a bottleneck of the access network because of the serious congestion of a large number of data packets transmitted to the gateway node. Anycast is a new network routing model which can increase service availability and provide efficient load distribution. If there are several gateway nodes in WMN, the clients in the bottom layer have greater room for choice of accessing Internet. They only need to choose any one gateway node. In WMN, all the gateway nodes belong to an Anycast Group, client chooses the optimal gateway through Anycast Routing. mesh network anycast multi-path Source Routing Protocol( MAMSR)is based on the dynamic source routing and anycast routing which can select the best path to one gateway from the anycast node group, maintain high packet delivery rate, low delay and routing cost and keep WMN access networks working stably and efficiently to meet the large number of Internet requirements
This paper presents an efficient routing protocol for WMNs that is able to handle stringent QoS requirements of real-time applications. It involves a very low control overhead and hence provides a high network throughput when the number of data sources in the network is large. The QoS-awareness in the protocol is achieved by a robust estimation of the available bandwidth of the wireless channel and a proactive discovery of the routing path by an accurate estimation of the wireless link quality. In addition, the protocol uses the multi-point relay (MPR) nodes to minimize the overhead due to flooding.
Based on AODV, an improved routing protocol is presented named Mesh On-Demand Distance Vector based on Weighted Link State (MODVWLS), in which link state including available bandwidth, error ratio and transmission delay rather than the number of hops is used as evaluation criteria, the cost (weight) of each hop is taken into account and the path with minimal accumulative weight is finally used as the preferred route.
The simulation performed in ns-2 shows that the packet delivery fraction goes up and the average end-to-end delay declines as the pause time increases. This is because as the pause time increases, the packet loss and the delay resulted from by routing discovery and maintenance decrease,the performance of MODVWLS varies smoothly and is obviously better than the one of AODV. The reason is that the packet loss and transmission delay caused by overload, retransmission, buffer overflow, routing discovery and routing maintenance, to some extent , are efficiently overcame by MODVWLS.Normalized routing load of MODVWLS is less than AODV.There is a slight increase in processing load at mesh routers due to calculating and storing weight of each loop and also routing overhead is increased a bit because link weight is included in the routing messages.
This paper proposes QoS Mesh routing protocol forIEEE 802.16 based wireless mesh networks. QoS Mesh Routing Protocol proposed in this paper is a proactive hop-by-hop QoS routing protocol. Most of the proposed routing protocols are based on 802.11 MAC protocol, but the paper claims that they are not suitable for WMN because of their small capacity which is inappropriate for backhaul networking in WMN. As IEEE 802.16 based WMNs cover a wider service range and provide a higher bandwidth than IEEE802.11 based WMNs, they are adequate for not only wireless Internet access but also multimedia applications such as videoconferencing. The protocol considers bandwidth and delay as default routing metrics and computer QoS paths based on them.QMRP is compared with QOLSR which is QoS extension of OLSR, and through simulation it is shown that QMRP outperforms QOLSR in terms of end-to-end delay, packet delivery ratio and routing overhead
A Simulation Based Performance Analysis of Reactive Routing Protocols in Wireless Mesh Networks 
In this paper, a detailed simulation based performance study and analysis is presented on the three reactive routing protocols Ad Hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Dynamic MANET On-demand (DYMO ).The simulation is carried out taking into consideration different quantitative metrics to compare the performance of routing protocols. In terms of PDR(Packet Delivery Ratio),when the traffic load is low,all the protocols have high PDR, however it declines by increasing traffic load.DSR performs worse than DYMO and AODV .In terms of end to end delay,at low traffic DSR is better than DYMO and AODV. with increasing load performance decreases. In terms of throughput.DSR outperforms AODV in less traffic environment. But in case of higher traffic, DSR has poor performance because of successive use of caching
The paper presents the analysis on one of the more popular and well analyzed reactive routing protocols the Ad-hoc On-Demand Distance Vector(AODV) routing protocol. First the issues of AODV in the hybrid WMN are discussed, and then the four variants of AODV are discussed in this paper.
• Link Quality Aware AODV (LQ-AODV)
• AODV-Path Accumulation (AODV-PA)
• AODV-Spanning Tree (AODV-ST)
• AODV-Hybrid Mesh (AODV-HM)
The paper proposes a novel routing protocol named HPRP (Hierarchical Probabilistic Routing Protocol) for wireless mesh networks, which introduces the concept of probabilistic routing for the first time. HPRP doesn’t choose a fixed path, but probabilistically selects next hop for a single packet according to the wireless link loss at that instant. The forwarding probability which is periodically updated makes links with lower loss rates have more chance to be selected. In this way, HPRP can efficiently mitigate the impact of high loss rates, balance the load of nodes and improve the throughput of the network.