Multi-hop Wireless Mesh Networks Research Articles

A Study on Development of Matrix Model of WMN for Mesh Clustering and its Validation

Tracking and tracing network nodes and monitoring network topology pose a huge challenge in Wireless Mesh Networks (WMNs). This becomes even more challenging in the scenario of multiple clusters, which keep performing hand-off handovers among each other for load management or link management purposes. In the dynamic and fragile WMN scenario, loss of connectivity is very common. In the case of multi-hop multi-gateway WMNs, such a scenario is very common. The architecture of the IEEE 802.11s WMN proposes a network wherein each node selects a gateway through which it routes its packets. A node selects the gateway based on its proximity in terms of the number of hop-distance and the Air Time Link Metric. Since the selection of gateway is done by a node on basis of its local information, more than often the scheduling of gateway becomes unfair. This leads to gateway congestion and a drop in the throughput of the network. In this paper, a model of a centralized gateway scheduling scheme is proposed. This paper proposes a matrix model of a clustered WMN. A well-defined gateway service set (cluster) is formed and then this is mapped onto the matrix model of the clustered WMN. In such a centralized scheme, an additional responsibility of tracking the nodes for connectivity is also addressed through this matrix model. This ensures no lost nodes or repeated nodes while the formation of clusters. Thereafter, the paper presents the process for validation of the integrity of WMN and its clusters through a mathematical model of WMN.

Localized Network Reconfiguration Plan for Wireless Mesh Networks

Abstract: Wireless mesh networks (WMNs) have emerged as a key technology for next-generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. In multi-hop wireless mesh networks (WMNs) experience frequent link failures caused by channel interference, dynamic obstacles and/or applications’ bandwidth demands. These failures cause severe performance degradation in WMNs or require expensive, manual network management for their real-time recovery. This paper presents an Autonomous network Reconfiguration System (ARS) that enables a multi-radio WMN to autonomously recover from local link failures to preserve network performance. ARS also improves channel efficiency by more than 90% over the other recovery methods. During their lifetime, multi-hop wireless mesh networks (WMNs) experience frequent link failures caused by channel interference, dynamic obstacles, and/or applications’ bandwidth demands. These failures cause severe performance degradation in WMNs or require expensive manual network management for their real-time recovery. By using channel and radio diversities in WMNs, ARS generates necessary changes in local radio and channel assignments in order to recover from failures. Next, based on the thus-generated configuration changes, the system cooperatively reconfigures network settings among local mesh routers. ARS has been evaluated extensively through ns2-based simulation. Our evaluation results show that ARS outperforms existing failure-recovery schemes in improving channel-efficiency by more than 90% and in the ability of meeting the applications’ bandwidth demands by an average of 200%. Keywords: WMN, ARS, AODV, WCETT, ETT, RSVP, DSDV, ETX, ETOPE, BLC

Modeling Wireless Mesh Networks for Load Management

Developing a simulation model for multi-hop multi-gateway wireless mesh networks (WMNs) is a challenging task. In this paper, a multi-hop multi-gateway WMN simulation model is developed in a step-by-step approach. This paper presents a MATLAB Simulink-based simulation model of Wireless Mesh Network (WMN) designed for easy optimization of layer 2. The proposed model is of special utility for the simulation of scheduling of GateWay (GW) and packet within a multi-hop multi gateway wireless network. The simulation model provides the flexibility of controlling the flow of packets through the networks. Load management among the GWs of WMN is performed in a distributed manner wherein the nodes based on their local knowledge of neighborhood beacons optimize their path to a GW. This paper presents a centralized Load Management Scheme (LMS). The LMS is based on the formation of Gateway Service Sets (GSS). The GSS is formed on basis of equal load distribution among the GWs. The proposed LMS is then analyzed for throughput improvement by leveraging the MATLAB Simulink model developed in the paper. A throughput improvement of almost 600% and a 40% reduction in packet loss was observed through simulations thus indicating the efficacy of the proposed LMS. The uniqueness of the simulation model presented in this paper are its scalability and flexibility in terms of network topology parameters.

Network coding assisted reliable multi-source multicasting over a multi-hop wireless mesh network

This paper introduces a Network Coding (NC) Assisted Reliable Multi-Source Multicasting (NCRMM) technique for multi-hop wireless mesh networks. The NCRMM scheme decreases the average number of packet transmissions in a network, which in turn reduces resource expenditure and traffic congestion problems. Multicast Least Cost Anypath Routing (MLCAR) algorithm is considered in NCRMM to select the neighbouring nodes participating in efficient packet transmission from multiple source nodes to the corresponding destination sets. At each intermediate node, a Coding Window (CW) is defined which stores packets received at the node from the same and/or different sessions. In the proposed NCRMM algorithm, packets are judiciously combined using intra-session and inter-session NC to ensure efficient distribution of coded packets among the neighbouring nodes. This is done while ensuring that packets transmitted at each source node are reliably received at all nodes of the corresponding destination set. The results are obtained for NCRMM and compared with that of the respective MLCAR and NC-MLCAR approach through extensive simulations. It is observed that the cost of multicasting packets in the NCRMM scheme is significantly less than that of the existing MLCAR and NC-MLCAR schemes for both independent and correlated link scenarios. Results comparing the complexity of the proposed NCRMM scheme with other multicasting schemes are also presented.

A softwarized and MEC-enabled protocol architecture supporting consumer mobility in Information-Centric Networks

Information-Centric Networking emerged as a powerful enabling technology for the provisioning of scalable and efficient real-time services in Future Internet, mobile architectures, and multi-hop wireless mesh networks. To serve mobile consumers, most of scientific contributions suggest to extend the information-centric communication primitives by means of a pull-based methodology, according to which the mobile consumer issues pending requests every time it reaches a new network attachment point. This approach, however, generates two important shortcomings. First, the requests delivered before the handover will generate stale paths with wrong forwarding information in their network routers. As a consequence, some new contents will be delivered also to previous locations, thus wasting bandwidth. Second, during handovers, mobile consumers may miss some contents released in real-time and lose the synchronization with the remote producer. In order to solve these issues, this work conceives a novel protocol architecture that successfully integrates and properly customizes the key functionalities of Information-Centric Networking, Multi-access Edge Computing, and Software Defined Networking paradigms. Specifically, the designed approach envisages that (1) Multi-access Edge Computing assists mobile consumers in retrieving data, while transparently managing the information-centric communication primitives and recovering the synchronization with the remote producer after the handover, (2) Software-Defined Controllers dynamically configure forwarding functionalities, and (3) Information-Centric Networking enables efficient data dissemination and delivers network control instructions. The impact of the devised protocol architecture on the communication overhead is analytically formulated and evaluated in scenarios with different topology, mobility, application settings, and number of mobile consumers. The comparison with respect to the pure Information-Centric Networking deployment demonstrates that the proposed solution ensures a reduction of the communication overhead up to 99.99% on the data plane, an overall bandwidth saving up to 99.93%, and a not negligible memory saving in intermediary routers. At the same time, the adoption of information-centric communication primitives for the control plane achieves an overhead reduction ranging from 29.36% to 51.13% with respect to an implementation based on the conventional OpenFlow protocol.

CARA-OHT: Collision-Aware Rate Adaptation for Optimal High-Throughput in IEEE 802.11s Wireless Mesh Networks

The wireless mesh network (WMN) is a future network technology that develops single-hop wireless local area networks (WLANs) into multi-hop wireless mesh networks, based on the IEEE 802.11s standard. However, this development still presents many challenges, such as determining the best route between sources and destinations, especially taking into account the use of the medium access control (MAC) and physical (PHY) layers of IEEE 802.11n/ac. Some papers have proposed rate adaptation algorithms particularly for single-hop networks; however, these only focused on mechanisms to find data rates suitable for channel conditions. In IEEE 802.11s WMNs, the design of the rate adaptation algorithm is more challenging. Besides considering the problem of channel quality and optimal throughput, it is necessary to also consider the problem of collision and the best route. It is important to take collision into account because the collision probability in multi-hop mesh networks is higher than that in single-hop networks and can lead to a lower throughput. Rate adaptation algorithms for IEEE 802.11s WMNs have been proposed in other papers, but they also do not consider the use of the MAC and PHY layers of IEEE 802.11n/ac. In this paper, we propose the collision-aware rate adaptation for optimal high-throughput (CARA-OHT) algorithm for WMN IEEE 802.11s. An evaluation through the extensive use of a network NS-3 simulator shows that the proposed algorithm exhibits a higher throughput than previously developed algorithms.

The Total Network Capacity of Wireless Mesh Networks for IoT Applications

<p class="0abstract">Computing and measuring the total capacity of a data network are a remarkably difficult problem. These metrics are directly linked to the available bandwidth to each wireless internet of things (IoT) device of the network. In this paper, the authors study the performance metrics associated with capacity traffic in multi-hop wireless mesh networks (WMNs). It is dedicated to Internet access assuming a time division multiple access (TDMA). They focus simultaneously on three key operating metrics, the total network capacity (TNC), total application network capacity (TANC), and the Average message time (AMS). They also analyze how parameters such as forward error correction (FEC) and acknowledgments (ACK) affect the overall network capacity under different operating conditions. Theoretical network capacity for WMNs, in this paper, is explored to draw attention to the number of open research issues</p>

A new fast polling algorithm in wireless mesh network for narrowband Internet of Things

We present a new fast polling algorithm (FPA) in a wireless mesh network (WMN) for Narrowband Internet of Things systems using multi-hop WMNs. We focus on wireless networks with stationary IoT remote telemetry units (IoT RTU), such as wireless network monitoring. The goal of the new FPA is to minimize the time required for supervisory control and data acquisition center to poll all RTUs one by one and to receive their responses using random network coding. We study the performance of the proposed FPA by applying it in a WMN composing of 3 and 50 RTUs with a sub-carrier spacing of 6.25 kHz, 12.5 kHz, 25 kHz, and 50 kHz. This paper also provides a comparative study of existing polling cycle mechanisms; we find that our FPA significantly outperforms previously proposed polling-cycle mechanisms with improvements typically exceeding 70%.

A Load Balancing Solution for Improving Video Quality in Loaded Wireless Network Conditions

There is an increasing user demand for high-quality content-rich multimedia services. Despite their advantages, current wireless networks in general and wireless mesh networks in particular have limitations in terms of quality of service (QoS) provisioning, especially when dealing with increased amounts of time sensitive traffic such as video. This paper presents video load balancing solution (ViLBaS), a load balancing-based mechanism which enhances delivery performance of video services over multi-hop wireless mesh networks and improves user quality of experience (QoE) levels. ViLBaS involves performance monitoring at the level of the nodes and load balancing by off-loading traffic from loaded nodes to less loaded neighboring nodes. Simulation-based results show how the proposed ViLBaS improves video delivery performance in terms of both QoS and QoE metrics [delay, throughput, packet loss, and peak signal-to-noise-ratio (PSNR)]. The comparison is performed against three other traditional approaches in different network topologies, for diverse video flow distributions, and different sizes for the video queue.

A Markov Model for Batch-Based Opportunistic Routing in Multi-Hop Wireless Mesh Networks

Opportunistic routing is a promising technique that has been proposed for wireless mesh networks. It achieves significant performance gains under unstable wireless links since it can take advantage of the broadcast nature of the wireless medium. Many protocols of opportunistic routing have been proposed to increase transmission reliability and network throughput. Instead of using a dedicated next hop, opportunistic routing can consider multiple downstream nodes as potential forwarders. The decision of which nodes being chosen to forward packets is made by the coordination schema. Although the coordination helps opportunistic routing to deliver opportunistic gains, it requires a batch-based schedule to minimize the cost, which may prevent spatial channel reuse and thus under utilize wireless media. In this paper, we explain the fundamental idea of opportunistic routing and propose a discrete-time Markov chain as a general model to map the transmission process. It demonstrates how to map batch-based packet transmissions in the network with state transitions in a Markov chain. Our model considers the pipelined data transfer and evaluates opportunistic routing under different wireless networks in terms of the expected number of transmissions and time slots. It shows both the pros and cons of opportunistic routing and thus helps in the design of future protocols of opportunistic routing.

A Joint Multi-Path and Multi-Channel Protocol for Traffic Routing in Smart Grid Neighborhood Area Networks.

In order to improve the management mechanisms of the electric energy transport infrastructures, the smart grid networks have associated data networks that are responsible for transporting the necessary information between the different elements of the electricity network and the control center. Besides, they make possible a more efficient use of this type of energy. Part of these data networks is comprised of the Neighborhood Area Networks (NANs), which are responsible for interconnecting the different smart meters and other possible devices present at the consumers’ premises with the control center. Among the proposed network technologies for NANs, wireless technologies are becoming more relevant due to their flexibility and increasing available bandwidth. In this paper, some general modifications are proposed for the routing protocol of the wireless multi-hop mesh networks standardized by the IEEE. In particular, the possibility of using multiple paths and transmission channels at the same time, depending on the quality of service needs of the different network traffic, is added. The proposed modifications have been implemented in the ns-3 simulator and evaluated in situations of high traffic load. Simulation results show improvements in the network performance in terms of packet delivery ratio, throughput and network transit time.

Performance Analysis of Network Coding with IEEE 802.11 DCF in Multi-Hop Wireless Networks

Network coding is an effective idea to boost the capacity of wireless networks, and a variety of studies have explored its advantages in different scenarios. However, there is not much analytical study on throughput and end-to-end delay of network coding in multi-hop wireless networks considering the specifications of IEEE 802.11 Distributed Coordination Function. In this paper, we utilize queuing theory to propose an analytical framework for bidirectional unicast flows in multi-hop wireless mesh networks. We study the throughput and end-to-end delay of inter-flow network coding under the IEEE 802.11 standard with CSMA/CA random access and exponential back-off time considering clock freezing and virtual carrier sensing, and formulate several parameters such as the probability of successful transmission in terms of bit error rate and collision probability, waiting time of packets at nodes, and retransmission mechanism. Our model uses a multi-class queuing network with stable queues, where coded packets have a non-preemptive higher priority over native packets, and forwarding of native packets is not delayed if no coding opportunities are available. Finally, we use computer simulations to verify the accuracy of our analytical model.

A Global Optimization-Based Routing Protocol for Cognitive-Radio-Enabled Smart Grid AMI Networks

Advanced metering infrastructure (AMI) networks, which are an integral component of the smart grid ecosystem, are practically deployed as a static multihop wireless mesh network. Recently, routing solutions for AMI networks have attracted a lot of attention in the literature. On the other hand, it is expected that the use of cognitive radio (CR) technology for AMI networks will be indispensable in near future. This paper investigates a global optimization-based routing protocol for enhancing quality of service in CR-enabled AMI networks. In accordance with practical requirements of smart grid applications, we propose a new RPL-based routing protocol, termed as directional mutation ant colony optimization-based cognitive RPL (DMACO-RPL), for CR-enabled AMI networks. This protocol utilizes a global optimization algorithm to select the best route from the whole network. In addition, DMACO-RPL explicitly protects primary (licensed) users while meeting the utility requirements of the secondary network. System-level simulations demonstrate that the proposed protocol enhances the performance of existing RPL-based routing protocols for CR-enabled AMI networks.

ENHANCED SECURITY FOR HOP BY HOP WIRELESS SENSOR NETWORK USING ELGAMAL ENCRYPTION ALGORITHM

The more modern network is unidirectional, also control of sensor activity, enabling. The WSN is built or even thousands of sensors of nodes, where each node is connected to on sensors. The sensor of the WSNs, from a simple star network to an advanced multi hop wireless mesh network can vary. The collecting of the data and controlling the node, may need to perform some successive on the measured data. Direct communication between individual nodes can also be required. The Task Manager Node (User) performs tasks in data storage, analysis and display. This proposed work empowers the intermediate nodes confirm the message with the goal that all corrupted message can be distinguished and dropped to save the sensor control. Hop by hop message security method for WSN without the edge constraint of the proficient. ElGamal encryption algorithm utilized in this work enables the semantic security. This framework successfully handles all sort of security issues. It likewise gives versatility, adaptable time authentication and source identity protection without any limitation on threshold.

Joint Inter-Flow Network Coding and Opportunistic Routing in Multi-Hop Wireless Mesh Networks: A Comprehensive Survey

Network coding and opportunistic routing are two recognized innovative ideas to improve the performance of wireless networks by utilizing the broadcast nature of the wireless medium. In the last decade, there has been considerable research on how to synergize inter-flow network coding and opportunistic routing in a single joint protocol outperforming each in any scenario. This paper explains the motivation behind the integration of these two techniques, and highlights certain scenarios in which the joint approach may even degrade the performance, emphasizing the fact that their synergistic effect cannot be accomplished with a naive and perfunctory combination. This survey paper also provides a comprehensive taxonomy of the joint protocols in terms of their fundamental components and associated challenges, and compares existing joint protocols. We also present concluding remarks along with an outline of future research directions.

Green-RPL: An Energy-Efficient Protocol for Cognitive Radio Enabled AMI Network in Smart Grid

With the capacity of achieving spectrum efficient wireless communications, cognitive radio enabled advanced metering infrastructure (CR-AMI) networks are expected to enhance the efficiency and practicability of future smart grids. CR-AMI networks which have been recognized as a fundamental component of the smart grid ecosystem, are practically utilized as a static multi-hop wireless mesh network. This paper focuses on the development of a novel routing protocol for low power and lossy networks based routing protocol for enhancing the energy efficiency in CR-AMI networks. For meeting the requirements of green communications in smart grids, the proposed routing protocol adopts the energy efficiency over virtual distance as the core of routing mechanism such that the energy-efficient route can be achieved. Furthermore, the protocol provides protection for primary users whilst meeting the utility requirements of secondary users. System-level evaluation indicates that the proposed protocol performs better than existing routing protocols for CR-AMI networks.

Distributed Channel Assignment Algorithm Based on Traffic Awareness in Wireless Mesh Networks

Recently, wireless mesh network (WMN) technology recently has been used in various industries. Especially, a number of multi-channel assignment schemes have been presented to improve the throughput of IEEE 802.11-based multi-hop WMN. However, performance of the conventional multi-channel assignment schemes is not enough to satisfy the industry requirements. We, thus, should study more about the multi-channel assignment scheme in order to enhance the performance. This paper proposes a novel channel assignment scheme that employs multi-channel and multi-Interface in the WMN. The proposed scheme obtains the traffic information of the network and does the efficient channel assignment without any message exchanges. We verify the efficiency of the proposed scheme through the mathematical modeling and the real-world experiments. The results show that the proposed scheme improves the throughput of the network compared with the conventional schemes.

Downlink and Uplink Message Size Impact on Round Trip Time Metric in Multi-Hop Wireless Mesh Networks

In this paper, the authors propose a novel real-time study metrics of Round Trip Time (RTT) for Multi-Hop Wireless Mesh Networks. They focus on real operational wireless networks with fixed nodes, such as industrial wireless networks. The main aim of the metric is to show the effect of the Downlink and Uplink message size (DMS and UMS) on RTT with and without Forward Error Correction (FEC), user data size without any headers, on RTT path between a source (Supervisory Control and Data Acquisition (SCADA) center) and a destination RTU (Remote Terminal Units). The metric assigns weights to links based on the RTT path of a packet size over the link path. They studied the performance of the metric by implementing it in three wireless scenarios consisting of 3, 4 and 5 nodes; each node represents a wireless radio IP router. They find that in a multi-hops environment, the real-time metric clearly shows the impact of DMS, UMS and FEC on RTT by making judicious use of the number of the hops.

Learning automata based multi-flow opportunistic routing algorithm in wireless mesh networks

Multi-hop Wireless Mesh Networks (WMNs) is a promising new technique for communication with routing protocol designs being critical to the effective and efficient of these WMNs. A common approach for routing traffic in these networks is to select a minimal distance from the source to destination as in wireless networks. Opportunistic Routing (OR) makes use of the broadcasting ability of wireless network and is especially very helpful for WMN because all nodes are static. Our proposed scheme of Multicast Opportunistic Routing (MOR) in WMNs is based on the broadcast transmissions and Learning Automata (LA) to expand the potential candidate nodes that can aid in the process of retransmission of the data. The receivers are required to be in sync with one another in order to avoid duplicated broadcasting of data which is generally achieved by formulating the forwarding candidates according to some LA based metric. The most helpful aspect of this protocol is that it intelligently learns from the past experience and improves its performance. The results obtained via this approach of MOR show that the proposed scheme outperforms some existing schemes and is an improved and more effective version of opportunistic routing in a mesh network.

Learning automata based multi-flow opportunistic routing algorithm in wireless mesh networks

Multi-hop Wireless Mesh Networks (WMNs) is a promising new technique for communication with routing protocol designs being critical to the effective and efficient of these WMNs. A common approach for routing traffic in these networks is to select a minimal distance from the source to destination as in wireless networks. Opportunistic Routing (OR) makes use of the broadcasting ability of wireless network and is especially very helpful for WMN because all nodes are static. Our proposed scheme of Multicast Opportunistic Routing (MOR) in WMNs is based on the broadcast transmissions and Learning Automata (LA) to expand the potential candidate nodes that can aid in the process of retransmission of the data. The receivers are required to be in sync with one another in order to avoid duplicated broadcasting of data which is generally achieved by formulating the forwarding candidates according to some LA based metric. The most helpful aspect of this protocol is that it intelligently learns from the past experience and improves its performance. The results obtained via this approach of MOR show that the proposed scheme outperforms some existing schemes and is an improved and more effective version of opportunistic routing in a mesh network.