WMN

Wireless Mesh Networks (WMNs) are a radio-based network technology that has gained considerable importance in network research community. It is a multi-hop wireless access network where nodes can act both as a host as well as a router. One of the factors that influence the performance of WMNs is the underlying routing protocol used. Thus, numbers of different routing protocols are proposed in recent years. There is a need to understand the versatile behavioral aspects of these routing protocols in a wireless mesh network with varying traffic loads, the number of sources and speed. In this paper, we compare and evaluate the performance of Ad-hoc On demand Distance Vector (AODV) protocol which is unicast protocol with Ad-hoc On-demand Multipath Distance Vector (AOMDV) protocol, which is multipath routing protocol. The performance differentials are analyzed using metrics such as end to end delay, packet delivery ratio and normalized routing overhead.

—Wireless ad-hoc networks are the self organizable, self-maintained and ad-hoc by nature. Due to high mobility of nodes, the energy of a node is most important parameter in respect of network lifetime.. Routing in such a network is a big challenge.In this paper, we have proposed a fuzzy based scheme for enhancing the efficiency of AODV in wireless ad-hoc networks. Next hop selection is performed on the basis of node energy, its neighbour node enrgy, node degree. Thus next hop selection is taken by considering a number of parameters including number of hops. As we are considering energy based parameters for next hop selection, the lifetime of nodes and network is improved. Each node is embedded with a fuzzy controller system through which output parameter chance is calculated. Based on this chance value next hop selection is carried out.We have compared the proposed routing protocol F-EEAODV with AODV, DSR, and DSDV routing protocols. Simulation work is carried out using NS-2. The simulation results taken by NS-2 shows that our proposed scheme outperforms as compared to AODV in respect of throughput, end-to-end delay, propagation delay.

Routing in ad-hoc networks is a big issue and challenge. AODV is most popular on demand routing protocol which is applicable in mostly all wireless ad-hoc networks. We here AODV routing protocol is analysed in wireless ad-hoc networks. Grid based topology has been used. Based on transmission rate and pause times, AODV is evaluated. Several routing parameters like throughput, dropped packets and average delay have been used for evaluation purposes. We have analysed AODV in several aspects at different network scenarios.

This paper evaluates the energy consumption of well-known routing protocols, along with other metrics such as throughput, packet delivery ratio (PDR), and delay in different scenarios. We consider two other metrics in order to capture the efficiency of the energy consumption: e-throughput which is the ratio between the consumed energy and the throughput; and the e-PDR which is the ratio between the consumed energy and the PDR. We compare four routing protocols: AODV, OLSR, and HWMP in Reactive and Proactive modes. The number of nodes is varying between 25 and 81 nodes, with different mobility models. Simulations are conducted using NS3 and the parameters of a real network interface card. From the results, AODV presents the lowest energy consumption and a better e-Throughput. OLSR provides a better e-PDR in mobile scenarios. With a smaller e-PDR and e-Throughput, the proactive mode of HWMP is more energy efficient than the reactive mode.

Wireless mesh networks (WMNs) have been proposed as a key technology for next generation wireless
networking to provide last-mile broadband access. Here we have given our observation and study for end
to-end bandwidth estimation in WMNs. End-to-end Bandwidth Estimation is an important metric for
network management and monitoring. It can also improve the effectiveness of congestion control
mechanism, audio/video stream adoration and dynamic overlay. In recent years, many techniques have
been developed for bandwidth estimation in the wired as well as the last-hop wireless networks, but they
under-perform in WMNs. We investigate attributes that can affect the bandwidth estimation in WNMs; we
found existing techniques do not consider the effect of attributes like CSMA/CA-based contending traffic
and high interference interference that leads to the error full estimation.
In this paper, we present an active bandwidth measurement technique called Bandwidth Probe based on the
packet dispersion principle. It measures the steady state bandwidth of the system while considering the
effects of the FIFO cross and CSMA/CA-based contending traffic. It is also mitigating the effect of
interference. We also show how to achieve the stationary state behaviour of the system to limit the number
of probe packets. On simulation, Bandwidth Probe gives a accurate estimation of the available bandwidth
using average convergence time and lower intrusiveness.

By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.

Abstract-VoIP services are getting more and more popular day by day. In order to meet the users demand for such services irrespective of users location requires wide area wireless coverage.To this extent, wireless mesh networks have been considered as practical and inexpensive solution.In order to improve the performance of VoIP services, techniques like packet aggregation are done. This paper focuses on finding the effect of packet aggregation on various parameters like aggregation delay, end to end delay and MOS etc. Results obtained through simulations done on Qualnet Simulator concludes that packet aggregation is justified upto a certain extent only as after that most of the users get dissatisfied.

One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.

One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.

Wireless Mesh Networking (WMN) technology provides a key revolutionary to the future backbone network access. WMN adopt a multihop based transmission to improve end to end data delivery. The 802.11s MAC (Medium Access Control) is designed using CSMA (Carrier Sense Medium Access) protocol which result in collision of slot due to failure in detecting hidden node in WMN. Various methodologies have been developed to optimize the MAC and hidden node and exposed node detection algorithm in recent time to utilize slot efficiently and reduce latency. Slot reutilization is an effective way in reducing latency but due to improper detection of hidden node of existing algorithm the latency is increased. To overcome this, our work propose an efficient device classification based MAC scheduler by adopting a cross layer design to reduce the latency. The experiment are conducted by varying network size and density and the outcome shows that the proposed approach perform better than existing CSMA/OCA in term of latency.

By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.