Communication In Wireless Mesh Networks Research Articles

Modeling a Novel Network Coding Aware Routing Protocol for Enhancement of Network Performance in Wireless Mesh Network

A Wireless Mesh Network (WMN) is a multi-hop network that gains the benefits of low deployment cost, fast access speed, expanded service coverage and large network capacity. However, the multi-hop communication in WMNs limits the throughput capacity due to increased number of packet transmissions. As a result, network coding is a recently emerged paradigm that can enhance the throughput capacity (i.e. network throughput) by minimizing the quantity of network workload and at the same time it ensures the data transfer among all the users. Further, with network coding the transmission effectiveness of a node can be improved by encoding (combining) several packets collectively and verifies whether the coding strategies is satisfied or not. Subsequently, if the coding strategies are satisfied then it transmits only the resultant encoded packet to the desired destination. In other words, network coding can improve the network throughput in WMNs by minimizing the transmission counts needed to transfer several packets to the destination. It should be noted that, while employing network coding in WMNs there are several challenges that should be compensated such as (i) identifying packets that can be combined (encoded) collectively and (ii) integrating the coding strategies in routing protocols. In this paper, we proposed a new mesh routing protocol that integrates network-coding called as Network Coding Aware Routing (Net-CART) protocol. Therefore, to enjoy the whole benefit of network coding a Net-CART protocol uses the innovative routing metric called Code-Aware and Load-Aware Routing Metric. Additionally, to identify numerous ‘coding structures’ and to support number of ‘packet encodings’ an improved set of coding strategies known as Enhanced Universal Coding Strategies is also proposed. The proposed Net-CART protocol comprising an improved set of coding strategies and a new routing-metric considers both the coding-opportunities and “network workload”. The simulation study carried out in wide forms of network configurations showed that Net-CART gives more fairness performances than other protocols.

An efficient channel assignment algorithm for multicast wireless mesh networks

Multicast can enhance the performance of wireless mesh networks (WMNs) effectively, which has attracted great attentions in recent years. However, multicast communication in WMNs requires efficient channel assignment strategy to reduce the total network interference and maximize the network throughput. In this paper, the concept of local multicast is proposed to measure interference and solve hidden channel problem in multicast communication. Basing on the concept, we propose a channel assignment algorithm considering the interference of local multicast and forwarding weight of each node (LMFW). The algorithm fully considers partially overlapped channels and orthogonal channels to improve the network performance. Simulations show that the proposed algorithm can reduce interference and improve network capacity of WMNs.

Online machine learning algorithms to predict link quality in community wireless mesh networks

Accurate link quality predictions are key in community wireless mesh networks (CWMNs) to improve the performance of routing protocols. Unlike other techniques, online machine learning algorithms can be used to build link quality predictors that are adaptive without requiring a predeployment effort. However, the use of these algorithms to make link quality predictions in a CWMN has not been previously explored. This paper analyses the performance of 4 well-known online machine learning algorithms for link quality prediction in a CWMN in terms of accuracy and computational load. Based on this study, a new hybrid online algorithm for link quality prediction is proposed. The evaluation of the proposed algorithm using data from a real large scale CWMN shows that it can achieve a high accuracy while generating a low computational load.

A Summary of Multicast Routing Algorithms in Wireless Mesh Networks

Wireless Mesh Network (WMN) presents us a key emerging technology which can construct the next generation wireless multi-hop network. It combines the advantages of both mobile ad-hoc network (MANET) and traditional fixed network. The applications of WMNs also attract significant industrial and academic attentions. As a vital function of network communication, multicast is normally applied to transmit data for high-definition video and gaming in WMNs. Therefore, the multicast routing algorithms are very important to the performance of group communication in WMNs. In this paper, we review a list of existing multicast routing algorithms in WMNs. Based on the findings, we also point out the open issues of multicast routing algorithms.

IJARCCE - Computer and Communication Engineering

QoS (Quality of Service) aware spectrum sensing and channel allocation in cognitive radio wireless mesh networks is a continuous practice due to the divergent scope of communication in wireless mesh networks. Henceforth the current research is moving in a direction to find effective solutions towards QoS aware spectrum sensing and channel allocation. But all of these solutions are specific to one or two QoS factors. According to the real-time practices the QoS assessment by one or two factors is impractical. Moreover majority of current approaches are delivering the computational complexity as O(n2), which due to the magnification of number evolution against the increment in number of channel availability in cognitive radio wireless mesh networks. In this context here we devised a Neighbor Conduct Sensitive QoS variance assessment strategy for cooperative spectrum sensing and channel allocation strategy, which enables to assess the QoS state of a spectrum under possible malicious cooperation that is based on multiple number of QoS factors and also should stabilize the computational complexity to O(n*log(n)). The experiment results are indicating the significance of the proposed model towards scalable and robust QoS variance aware spectrum sensing and channel allocation strategy for cognitive radio wireless mesh networks.

Promoting wired links in wireless mesh networks: an efficient engineering solution.

Wireless Mesh Networks (WMNs) cannot completely guarantee good performance of traffic sources such as video streaming. To improve the network performance, this study proposes an efficient engineering solution named Wireless-to-Ethernet-Mesh-Portal-Passageway (WEMPP) that allows effective use of wired communication in WMNs. WEMPP permits transmitting data through wired and stable paths even when the destination is in the same network as the source (Intra-traffic). Tested with four popular routing protocols (Optimized Link State Routing or OLSR as a proactive protocol, Dynamic MANET On-demand or DYMO as a reactive protocol, DYMO with spanning tree ability and HWMP), WEMPP considerably decreases the end-to-end delay, jitter, contentions and interferences on nodes, even when the network size or density varies. WEMPP is also cost-effective and increases the network throughput. Moreover, in contrast to solutions proposed by previous studies, WEMPP is easily implemented by modifying the firmware of the actual Ethernet hardware without altering the routing protocols and/or the functionality of the IP/MAC/Upper layers. In fact, there is no need for modifying the functionalities of other mesh components in order to work with WEMPPs. The results of this study show that WEMPP significantly increases the performance of all routing protocols, thus leading to better video quality on nodes.

Matrix-based key pre-distribution schemes in WMNs using pre and post deployment knowledge

Like other types of wireless networks, wireless communication in wireless mesh networks (WMNs) is vulnerable to many malicious activities. Thus it is a must to protect wireless transmission by proper security measures. As a fundamental security technology, symmetric key pre-distribution has been widely studied to ensure the security of wireless communication. This paper presents two matrix-based pairwise key establishment schemes for mesh clients. In our schemes, a mesh client only needs to pre-load an independent key seed which can be used to generate a column of secret matrix. It can establish pairwise keys with neighbour clients after mesh routers broadcast public matrices. Motivated by this heterogeneity (mesh routers are much more powerful than mesh clients, both in communication and storage), energy-consuming operations can be delegated to mesh routers to alleviate the overhead of mesh clients when they establish pairwise keys. By using pre and post deployment knowledge, neighbour mesh clients in our scheme can directly establish pairwise keys with a very light communication and storage cost.

Sparks in the Fog: Social and Economic Mechanisms as Enablers for Community Network Clouds

Internet and communication technologies have lowered the costs of enabling individuals and communities to collaborate together. This collaboration has provided new services like user-generated content and social computing, as evident from success stories like Wikipedia. Through collaboration, collectively built infrastructures like community wireless mesh networks where users provide the communication network, have also emerged. Community networks have demonstrated successful bandwidth sharing, but have not been able to extend their collective effort to other computing resources like storage and processing. The success of cloud computing has been enabled by economies of scale and the need for elastic, flexible and on-demand provisioning of computing services. The consolidation of today’s cloud technologies offers now the possibility of collectively built community clouds, building upon user-generated content and user-provided networks towards an ecosystem of cloud services. We explore in this paper how social and economic mechanisms can play a role in overcoming the barriers of voluntary resource provisioning in such community clouds, by analysing the costs involved in building these services and how they give value to the participants. We indicate socio-economic policies and how they can be implemented in community networks, to ease the uptake and ensure the sustainability of community clouds.

Latency-optimal communication in wireless mesh networks

Wireless mesh networking is an emerging communication paradigm to enable resilient, cost-efficient and reliable services for the future-generation wireless networks. We study the minimum-latency communication primitive of gossiping (all-to-all communication) in known topology Wireless Mesh Networks (WMNs), i.e., where the schedule of transmissions is pre-computed in advance based on full knowledge about the size and the topology of the WMN. Each mesh node in the WMN is initially given a message and the objective is to design a minimum-latency schedule such that each mesh node distributes its message to all other mesh nodes. The problem of computing a minimum-latency gossiping schedule for a given WMN is NP-hard, hence it is only possible to get a polynomial approximation algorithm. In this paper, we show a deterministic approximation algorithm that can complete gossiping task in O(D+ΔlognlogΔ) time units in any WMN of size n, diameter D, and maximum degree Δ. This is an asymptotically optimal schedule in the sense that there exists a WMN topology, specifically a Δ-regular tree, in which the gossiping task cannot be accomplished in less than Ω(D+ΔlognlogΔ) units of time. Our algorithm also improves on currently best known gossiping schedule of length O(D+ΔlognlogΔ−loglogn) (Cicalese et al. (2009) [4]).

Harnessing the High Bandwidth of Multiradio Multichannel 802.11n Mesh Networks

There has been an increasing interest in deploying wireless mesh networks (WMNs) for communication and video surveillance purposes thanks to its low cost and ease of deployment. It is well known that a major drawback of WMN is multihop bandwidth degradation, which is primarily caused by contention and radio interference. The use of mesh nodes with multiple radios and channels has been regarded as a straightforward solution to the problem in the research community. However, we demonstrate in this paper through real-world experiments that such an approach cannot resolve the multihop TCP throughput degradation problem in IEEE 802.11n mesh networks. With extensive experimentation, we verify that the degradation is principally caused by the increase in TCP Round-Trip Time (RTT) when the number of hops increases. TCP throughput is fundamentally limited inversely by the RTT. We find that the multihop TCP throughput (up to five hops) when using 802.11n is no better than when using 802.11a, despite the much higher data rate 802.11n. We attempt to use multiple parallel TCP connections as a remedy to the problem, and it turns out that the wireless bandwidth can be fully utilized with a sufficient number of parallel streams. In general, our results give a key message that TCP tuning (e.g., setting the correct TCP buffers and use of parallel streams) is of paramount importance in high-bandwidth multihop wireless mesh networks that employ the latest wireless standards. These tuning techniques have to be implemented into commercial products to fully leverage the ever advancing wireless technologies to support the growing demand of multihop communications in wireless mesh networks.

Matrix-based pairwise key establishment for wireless mesh networks

Wireless communication in wireless mesh networks (WMNs), like other types of wireless networks, is vulnerable to many malicious activities such as eavesdropping. As one of the fundamental security ...

A Matrix-Based Pairwise Key Establishment Scheme for Wireless Mesh Networks Using Pre Deployment Knowledge

Due to the nature of wireless transmission, communication in wireless mesh networks (WMNs) is vulnerable to many adversarial activities including eavesdropping. Pairwise key establishment is one of the fundamental issues in securing WMNs. This paper presents a new matrix based pairwise key establishment scheme. Mesh client in our scheme only needs to prestore a key seed, which can be used to generate a column of secret matrix. It can establish pairwise keys with other clients after mesh routers broadcast public matrices. Our scheme is motivated by the fact that in WMNs, mesh routers are more powerful than mesh clients, both in computation and communication. Besides, we employ the pre deployment knowledge to reduce the computational cost of mesh clients. Security and complexity analysis show that the new scheme possesses several desirable features: 1) neighbor mesh clients can directly establish pairwise keys; 2) the new scheme is updatable, scalable, and robust against node capture attacks; and 3) communication and storage costs at mesh clients are significantly reduced.

Anonymous Routing Protocol Based on Weil Pairing for Wireless Mesh Networks

This paper proposes an efficient, secure and anonymous routing protocol based on Weil pairing for wireless mesh networks (WMNs). The proposed protocol considers symmetric and asymmetric links during wireless communication in WMNs. A WMN integrates several types of wireless devices, and induces the asymmetric links that result from different transmission ranges of wireless devices. Enhancing the security and privacy of WMNs has been an important research focus in recent years. Most research on this topic has focused on providing security and anonymity for routing and data in symmetric links. However, the asymmetric links in these protocols have not been addressed. This paper proposes a novel distributed routing protocol suitable for WMNs that include symmetric and asymmetric links. The proposed protocol guarantees security, anonymity and high reliability in WMNs. The proposed protocol generates routes that are shorter than those of previous studies. The proposed scheme protects the real identities of the source and intermediate users, which remain unknown even to the mesh router, while still providing node authentication. Using the proposed protocol, mesh clients anonymously discover a secure route to the mesh router. This protocol also ensures data transmission anonymity and enhances WMN coverage, in addition to assuring security and anonymity.

Hierarchical agent-based secure and reliable multicast in wireless mesh networks

We propose and analyze a hierarchical agent-based secure and reliable multicast (HASRM) algorithm for efficiently supporting secure and reliable mobile multicast in wireless mesh networks, with design considerations given to minimize the overall network cost incurred by reliable multicast packet delivery, mobility management, security key management, and group membership maintenance. HASRM dynamically maintains a group of multicast agents running on mesh routers for integrated mobility and multicast service management and leverages a hierarchical multicast structure for secure and reliable multicast data delivery. The regional service size of each multicast agent is a key design parameter. We show via model-based performance analysis and simulation validation that there exists an optimal regional service size that minimizes the overall communication cost and the optimal regional service size can be dynamically determined. We demonstrate that HASRM under optimal settings significantly outperforms traditional algorithms based on shortest-path multicast trees extended with user mobility, security, and reliability support. We also show that a variant of HASRM is superior to a recently proposed multicast algorithm for secure group communication in wireless mesh networks.

Matrix-based pairwise key establishment for wireless mesh networks

Wireless communication in wireless mesh networks (WMNs), like other types of wireless networks, is vulnerable to many malicious activities such as eavesdropping. As one of the fundamental security technologies, pairwise key establishment has been widely studied to secure wireless communication. In this paper, we propose a new matrix-based pairwise key establishment scheme for mesh clients in WMNs. A fact in WMNs is that mesh routers are more powerful than mesh clients, in both communication and storage. Motivated by this fact, expensive operations can be delegated to mesh routers to alleviate the overhead of mesh clients when establishing pairwise keys between them. Compared with other matrix-based schemes, our scheme has significant advantages: any two mesh clients can directly establish pairwise keys while communication and storage costs of mesh clients are significantly reduced.

Large-scale access scheduling in wireless mesh networks using social centrality

Wireless mesh networking is an economic and convenient way to provide last mile Internet access through ad hoc peer-to-peer communication links. However, without systematic network configuration and channel resource management, these networks suffer from scalability, performance degradation and service disruption issues due to overwhelming co-channel interference, unscrupulous channel utilization and inherent network mobility. The IEEE 802.11 DCF and EDCA mechanisms based on CSMA/CA are the most widely used random channel access mechanisms, but unfortunately these cannot effectively eliminate hidden terminal and exposed terminal problems in multi-hop scenarios. Social network analysis techniques proposed for economic and social studies have recently been shown to be a successful approach for characterizing information propagation in multi-hop wireless networks. We propose a set of efficient resource allocation algorithms and channel access scheduling protocols based on Latin squares and social centrality metrics for wireless mesh networks (WMNs) with multi-radio multi-channel (MRMC) communication capabilities, called LaSo, which can coexist with IEEE 802.11 DCF and be effectively applied in large scale WMNs. Based on interference information provided by the interference graph, LaSo uses nodal degree centrality to form cliques for intra-cluster communication, and betweenness centrality to choose bridge nodes to form cliques for inter-cluster communication in WMNs, and then applies Latin squares to map the clique-based clustering structure to radios and channels for wireless communication purposes. Afterwards, LaSo again applies Latin squares to schedule the channel access amongst nodes within each cluster in a collision-free manner. We evaluate LaSo using simulations, and results show that LaSo achieves much better performance than existing IEEE 802.11 standards and other multi-channel access control protocols.

Architectural framework for mobile multicast support in wireless mesh networks

A wireless mesh network (WMN) is an infrastructure multihop ad hoc network with broadband capabilities. Multicasting is an efficient mechanism for delivery of group communication. However, the current IEEE 802.11s standard has no provision for efficient group communication delivery. Furthermore, the disruption in internet connectivity and loss of information when a mobile mesh client changes its point of attachment may lead to disruption in an ongoing session. The internet gateway (IGW), a prominent component, serves as the wired bridge between the mesh nodes and the internet, thus its placement determines the overall quality of communication in WMNs. Accordingly, a structural design for supporting multicast services in this architecture is indispensable. The main question this paper addresses is how multicast can be efficiently supported for mobile mesh clients in WMN architecture. This paper adopts the technique of employing multicast architecture to solve mobility problems for mobile mesh clients. Thus a framework of novel architecture for supporting multicast services for group application delivery over WMN is presented. The proposed architecture features enhanced functionality of IGW, shared multicast tree, optimal design for IGW and core placement, hierarchical mobility management, load balancing, and robustness. The overall objective is the provision of cost efficient WMN architecture while mobile multicast traffic delivery is supported optimally. This is the first effort reporting multicast service support framework for mobile mesh clients with a focus on IGW placement and functionality.

Proportional fairness in MAC layer channel access of IEEE 802.11s EDCA based wireless mesh networks

Fairness provisioning in IEEE 802.11s EDCA based Wireless Mesh Networks (WMNs) is a very challenging task due to relayed traffic and traffic load variation among mesh routers. Because of bursty traffic in general purpose community wireless mesh networks, proportional fairness is more suited than max–min fairness, where mesh routers and clients should get channel access proportional to their traffic load. However, proportional fairness is hard to achieve by solving optimization function because of non-linearity and non-concave property of the objective function. In this paper, a probabilistic approach is proposed to provide proportional fairness without solving global non-linear and non-concave optimization. Every mesh node use a load estimation strategy to estimate total traffic load that it needs to forward. The required channel share of a mesh node should be proportional to its traffic load, whereas, the total normalized channel share for all the contending mesh nodes should be kept less than unity to satisfy the clique constraint. The network architecture and contention property in WMN are explored to deduce the required channel share of mesh nodes. A probabilistic approach is used to tune the contention window based on the difference between actual channel share and required channel share, so that the node with more traffic load gets more channel share. A discrete time Markov Chain based modeling is used to deduce the overall network throughput for the proposed scheme. Simulation result shows that the proposed scheme works better than the standard IEEE 802.11s based EDCA MAC in terms of fairness and throughput.

Securing wireless mesh networks in a unified security framework with corruption-resilience

Wireless mesh networks (WMN) are expected to be widespread due to their excellent properties like low-cost deployment, easy arrangement and self-organization. Although some proposed security schemes for WMNs with various security objectives have been put forward recently, it is a challenge to employ a uniform cryptography context to achieve resilience to trust authority corruption and maintain trust relationships flexibly among different domains. In this paper, a unified security framework (USF) for multi-domain wireless mesh networks is proposed. The identity-based encryption and the certificateless signature are unified in the proposed cryptography operations utilizing bilinear groups to solve key escrow problem. To ensure secure muliti-hop communication in WMN, the intra and inter domain authentication and key agreement protocols are devised sophisticatedly to achieve perfect forward secrecy and attack-resilience. With the enhanced security properties in the USF scheme, when a trust authority is corrupted, parts of the WMN could be survivable in the local area if proper measures are taken. A formal security proof of the proposed authentication protocols is presented based on Universal Composable security theory. The detailed performance analysis shows that the enhanced security attributes are achieved with reasonable overhead.

A routing protocol suitable for backhaul access in wireless mesh networks

This work proposes the Wireless-mesh-network Proactive Routing (WPR) protocol for wireless mesh networks, which are typically employed to provide backhaul access. WPR computes routes based on link states and, unlike current routing protocols, it uses two algorithms to improve communications in wireless mesh networks taking advantage of traffic concentration on links close to the network gateways. WPR introduces a controlled-flooding algorithm to reduce routing control overhead by considering the network topology similar to a tree. The main goal is to improve overall efficiency by saving network resources and avoiding network bottlenecks. In addition, WPR avoids redundant messages by selecting a subset of one-hop neighbors, the AMPR (Adapted MultiPoint Relay), needed to reach all two-hop ones. We first analyze the proposed algorithms compared with the algorithms used by OLSR for the same tasks in terms of running time, optimality, and number of routing messages. Results show that the algorithms proposed by WPR are more efficient than the algorithms used by OLSR in running time and number of routing messages. In addition, we also perform simulations to evaluate the performance of WPR. Results reveal that the aggregated throughput of WPR outperforms OLSR by up to 27% using a combination of web and backbone internal traffic despite our design assumption of traffic convergence toward gateways.