Mobility-aware clustering algorithms with interference constraints in wireless mesh networks

Resource allocation and admission control algorithm based on non-cooperation game in wireless mesh networks

The impact of interference-aware routing metrics on video streaming in Wireless Mesh Networks

Wireless Mesh Networks (WMNs) integrate the advantages of WLANs and mobile Ad Hoc networks, which have become the key techniques of next-generation wireless networks in the context of emergency recovery. Wireless Mesh Networks (WMNs) are multi-hop wireless networks with instant deployment, self-healing, self-organization and self-configuration features. These capabilities make WMNs a promising technology for incident and emergency communication. An incident area network (IAN) needs a reliable and lively routing path during disaster recovery and emergency response operations when infrastructure-based communications and power resources have been destroyed and no routes are available. Power aware routing plays a significant role in WMNs, in order to provide continuous efficient emergency services. The existing power aware routing algorithms used in wireless networks cannot fully fit the characteristics of WMNs, to be used for emergency recovery. This paper proposes a power aware routing algorithm (PARA) for WMNs, which selects optimal paths to send packets, mainly based on the power level of next node along the path. This algorithm was implemented and tested in a proven simulator. The analytic results show that the proposed power node-type aware routing algorithm metric can clearly improve the network performance by reducing the network overheads and maintaining a high delivery ratio with low latency.

Nowadays there are inexpensive WiFi devices that have fostered the deployment of wireless communities. Well known routing protocols used in the Internet do not fit well to time varying characteristic of wireless networks. This has motivated an intensive research on routing protocols for wireless mesh networks. At this time there are a number of mature and stable implementations that are being deployed in production networks. In this paper we focus on the experimental evaluation of a production Wireless Mesh network being deployed in a testbed at Universitat Politecnica de Catalunya (UPC) and a quarter of the city of Barcelona, Spain. To our best knowledge, this is the first paper where a production community wireless network using 802.11an is analyzed.

There is a growing interest in ad hoc wireless networking internationally, due to the great cost in infrastructure and the time delay for deployment for new traditional wireless networks for a specific purpose (i.e. cellular systems). The interest arises from the possibility of delivering telecommunication services rapidly and with the reduced needs for costly generic infrastructure. Examples of such services include, among others, a convention where a large number of people are concentrated in a limited geographical area, a university campus with a great density of telecommunication users, or even a disaster area where the fixed infrastructure have been damaged. In most examples, ad hoc wireless networks may complement or replace the existing wireless telecommunications infrastructure. One flavor of ad hoc wireless networks that is of interest in this context, and is well adapted to the Lebanese market, are wireless mesh networks (WMN). We propose that the proliferation of WiFi hotspots in high-density areas of population in Lebanon forms the basis of deployment of mesh routers for a WMN. Of specific interest is to be able to use the dense infrastructure of GSM-EDGE (and in the future HSUPA) cellular networks in Lebanon to interconnect those routers in specific locations where it will be hard to deploy additional fixed and cumbersome cellular infrastructure. Locations where hotspots are already deployed (commercial centers, university campuses, business areas, etc.) or could be deployed for special events (conventions, concerts, etc.) could thus be interconnected in a hybrid wireless network, resulting in significantly increased capacity of the network for local voice and data traffic at little additional infrastructure cost. Furthermore, this could a preliminary step for direct connection between the mesh routers and not via the cellular network, into what will become a full- fledged WMN. The structure of the paper is as follows: section the author gives an introduction on ad hoc wireless networks; section II describes WMN and define the design issues of WMN; in section III, we look at a proposed scenario for deployment of WMNs in the Lebanese market and the issues of interconnection with the GSM networks. We will conclude in section IV.

Wireless Mesh Networks (WMNs) are attracting a lot of attention from wireless network researchers, because of their potential use in several fields such as collaborative computing and communications. In this paper, we present the implementation of a testbed for WMNs using Raspbian and OpenWRT OSs. We analyze the performance of Optimized Link State Routing (OLSR) protocol in an indoor scenario. For evaluation we considered throughput, Packet Delivery Ratio (PDR), delay, jitter and hop count metrics. The experimental results show that the testbed mounted in OpenWRT has better results than Raspbian.

The wireless mesh networks (WMNs) have become one of the popular technologies of the wireless network utilization. WMN provides reliable and scalable wireless network because of its features such as dynamic self-organizing, self-configuring, Self-managing and self-healing. Routing protocols play an essential role in finding and establishing an active route from a source to a destination in WMNs. This article focuses on the performance evaluation and comparison of some routing protocols commonly used in WMNs for VoIP application: AODV, DSR, OLSR and TORA has been investigated over client Wireless Mesh Networks based on OPNET simulation in a different network sizes and mobility. This article presents a background of some designs and solutions based on an elaborated simulation investigation. The performance comparisons are carried out with regard to the node variation in network sizing and mobility. Based on the empirical outputs, the authors suggested that to utilize a specific routing protocol in certain situations.

The integration of passive optical networks (PONs) and wireless mesh networks (WMNs) into Fiber- Wireless (FiWi) networks can lead to effective access networks. Existing routing schemes for FiWi networks consider mainly hop-count and delay metrics over a flat WMN node topology and do not specifically prioritize the local network structure, i.e., the local wireless-optical network gateway. In this study, we explore a simple, yet effective routing algorithm for FiWi networks with a WMN organized into zones operating on different radio channels. We examine the effects of routing the traffic into and out of a zone through one or more cluster heads. We investigate the effectiveness of localized routing that prioritizes transmissions over the local gateway to the optical network and avoids wireless packet transmissions in zones that do not contain the packet source or destination. We find that this combination of clustered and localized routing (CluLoR) gives good throughput-delay performance compared to routing schemes that transmit packets wirelessly through “transit zones” (that do not contain the packet source or destination) following minimum hop-count routing.

Wireless mesh network is a network implemented over a wireless local area network (LAN), and its infrastructure type is decentralized, relatively inexpensive, reliable, and resilient since the wireless routers are often static and not powered by batteries. In addition, the access points (routers) seldom change their positions in wireless mesh networks, and some wireless nodes have gateway functions to provide the connectivity to the Internet. Therefore, such networks behave almost like wired networks with infrequent topology changes and limited node failures. Due to these good properties and potential applications such as providing commercial Internet access to residents and local businesses, wireless mesh networks have drawn a lot of attention in recent years. For example, wireless mesh networks are being used as the last mile for extending the Internet connectivity for mobile nodes. In addition, some commercial deployments of multihop wireless meshes are already in the works. For instance, a number of mesh networks have been deployed in some cities of the United States, including Medford, Oregon, and cities in Minnesota [4]. Unlike traditional wired network, close-by mesh routers share certain wireless channels and the capacity of wireless mesh network will be increased tremendously when extending from a single channel model to a multiradio, multichannel, multihop model. For example, if two nodes vi and v j could communicate with each other by channel f1, and both nodes have at least one more available network interface cards, which could operate on another channel f2, if f2 is also available for both nodes, vi and v j could use both f1 and f2 to communicate simultaneously. When such cases are applied to more wireless nodes, the throughput of a wireless network will be increased tremendously.

The paradigm of wireless mesh networks has matured in the last decade after extensive research and development. As opposed to the time of their inception, current mesh networks are expected to deliver carrier-grade access services to their users. With the increasing expectations, it is generally recognized that there is a lack of understanding of the level of service continuity that mesh networks can provide to its users. In this research, we address a set of network design problems and propose solutions to improve the service continuity of wireless mesh networks. First, we investigate power control as a network layer problem in mesh networks. It is commonly acknowledged that reducing transmit power levels of nodes to the minimum required to retain connectivity always increases network capacity. In this work, we show that increasing power level of nodes can be beneficial in many cases depending on network’s traffic and topological characteristics. With extensive analysis and simulations, we characterize achievable spatial reuse and capacity with respect to power control in various practical scenarios. Second, we address the problem of generation of traffic hot-spots in wireless networks, and propose a novel power control scheme for load balancing. Using a heuristic based on the concept of centrality, we show that if we increase the power levels of only the nodes which are expected to relay more packets, significant relay load balancing can be achieved even using shortest path routing. Different from divergent routing schemes, such load balancing strategy is applicable to any arbitrary topology and traffic pattern. With this understanding of power control and load balancing, we investigate the service continuity issues of an urban-scale mesh networks. We define and study two essential service continuity metrics - connection robustness (K-center availability) and performance robustness (K-center performability). K-center availability is the fraction of the time a mesh network is available to its users, while performability is a composite measure of performance (here - throughput) and robustness that captures aggregate experience of mesh users over a long period of time. We develop efficient algorithms for estimating these quantities for large urban-scale meshes and study their characteristics in various existing mesh networks. Our study reveals numerous novel insights that can help in designing mesh networks with high availability and performability. While evaluating the performability, we used ideal case throughput performance estimation that ensures fair network resource allocation among the flows. Although this allows faster computation which is especially necessary for large state space exploration, it is difficult to implement in real-world using CSMA/CA MAC. To address this, we target the issue of unfair and lower utilization of network resources in wireless networks. Specifically, in a mesh network, nodes closer to gateways often achieve a larger share of bandwidth resources while nodes farther away often starve for useful bandwidth. Using back-pressure utility maximization framework, we provide a solution to the issue of spatial bias that can be implemented using current 802.11 standards. To further increase the efficiency of back-pressure policy in mesh networks, we propose a dynamic packet aggregation scheme that is especially effective in Internet-like packet size distribution. Along the same lines, we use the back-pressure invariants to develop a variable channel width assignment scheme that can yield maximum benefits of using varying-sized channels while remaining fair in network-wide resource allocation.

In emergency cases of the building, users need to grasp the disaster situation and evacuation routes for an efficient and rapid evacuation. It is expected that multihop wireless network systems such as a wireless mesh network are useful to share the disaster information among users. The wireless mesh network is configured by user terminals and base stations which are deployed at the specified area by the administrators of the building. User terminals communicate with the others through the wireless mesh network without the aid of the infrastructure network and the central server. Access points are possible to work by battery power so that the wireless mesh network system is tolerant to the power outage. This paper proposes an evacuation route guidance scheme for building evacuation using wireless mesh network systems. User terminals grasp the up-to-date disaster situation in the building through the wireless mesh network, and then provide the evacuation route to the users. The timing of transmitting messages to share the information among users is crucial for the efficient and rapid evacuation. We implement the system into the network simulator and conduct the simulation experiments to confirm the network performance and the users’ evacuation time. Finally, we show the effect of the wireless mesh network and the effectiveness of the evacuation route guidance scheme.

The significant increase in Voice over IP (VoIP) service providers over the last few years has prompted an increase in VoIP services and currently poses additional challenges when deployed on wireless mesh network. Packet losses and delay due to interference in a wireless mesh network degrade significantly the VoIP call quality. In this work, we propose an approach inspired of Traffic Engineering Concept for wireless mesh network to provide differentiated services and therefore a better Quality of Service. We establish general criteria for these algorithms: routing using of calls statistics, minimizing network costs, and load balancing. Finally, we propose a solution that encompasses the different criteria presented in the paper.

Multihop wireless mesh networks are an attractive solution for providing last-mile connectivity. However, the shared nature of the transmission medium makes it challenging to fully exploit these networks. Nodes interfere with each other, resulting in packet loss and degraded network performance. In this paper, a routing metric specifically designed for WMNs is proposed. The Interference-Aware Routing metric (IAR) uses MAC-level information to measure the share of the channel that each link is able to utilize effectively. As a result, paths are selected that exhibit the least interference. Simulations show that utilizing this metric provides significant performance improvements in terms of end-to-end delay compared to several existing metrics.

Voice over IP (VoIP) over a wireless mesh network (WMN) is a killer application candidate of the next generation services over wireless and mobile network infrastructure. Yet, the routing and transport efficiencies in consideration of specific attributes of WMNs have been little emphasized. Distinctively from conventional networks, the major traffic pattern of WMNs is anycast (one-to-one-of-many). To fully utilize the service aspects of WMNs, load balancing and scalability should simultaneously be supported. For VoIP, one challenge is to maintain the perceived quality depending on both loss and delay. In this paper, we assess autonomous load balancing anycast routing regarding VoIP supportability. The protocol is based on physics analogy and a distributed algorithm. We compare the protocol with shortest-path routing and back-pressure routing via simulations. Simulation results exhibit that autonomous load balancing of the protocol efficiently supports voice calls to guarantee the certain level of quality.

Wireless technology is emerging as a key technology for the future networks. Wireless mesh networks (WMNs) have emerged as an indispensable technology for deployment of wireless services for various applications in personal, enterprise, and metropolitan areas. Researchers are working actively in different fields of WMNs for providing better services. Routing protocols play a vital role in WMNs to provide reliable configuration and maintenance of topology of the network. Designing a suitable cost metric for routing protocols to provide quality links for data transmission is the backbone of WMNs. Many cost metrics have been proposed for WMNs and is still an active research topic as new performance metrics need to be discovered due to the dynamics of this field. This paper considers the genetic algorithm-based routing technique for WMN.We have studied the existing cost metrics and proposed a genetic algorithm technique for routing in WMN. To evaluate the genetic algorithm, and to determine the relative performance of the genetic algorithm in the context of routing in WMN, we carry out experiments on two test systems. We have evaluated the quality of the results produced by our algorithm with the traditional hop count metric results. Our results show that routing in WMN using genetic algorithm produces better results as compared to traditional hop count metric results. Finally, we carry out a detailed analysis of results, which help us in gaining an insight into the suitability of genetic algorithm for routing in WMN.