Mobility-Aware Reassociation control in Wireless Mesh Networks

In a wireless mesh network, a client station needs to associate with a mesh access point for network access. Conventional association mechanisms assume a high-speed backhaul and only the access link being the bottleneck. This assumption holds for most WLANs, but in wireless mesh networks traffic could be bottlenecked either by the access link or by the bandwidth-limited wireless backhaul. In this paper, we propose an association mechanism for wireless mesh networks to improve stations' end- to-end communication performance with the Internet. A station makes its association decision by jointly considering the quality of the access link between the station and the candidate mesh access point as well as the cost of the multi-hop path from the mesh access point to the gateway. In addition, we design two access link metrics, Contention Aware Expected Transmission Time (CAETT) and Load Aware Expected Transmission Time (LAETT). The main strength of CAETT is incorporating the impact of 802.11 MAC layer contention on the bandwidth sharing among the multi-rate stations. LAETT further captures the traffic load. We evaluate the performance of our system through simulations and demonstrate that the proposed joint association mechanism with the CAETT/LAETT metric can significantly improve the end-to-end performance for wireless mesh networks by up to 60%.

A wireless mesh network (WMN) comprises of mesh access points (MAPs), mesh routers and mesh clients (MCs), where MAPs are almost static and form the back-bone of WMNs. MCs are wireless devices and dynamic in nature, communicating among themselves over possibly multi-hop paths, with or without the help of MAPs. Security has been a primary concern in order to provide protected communication in WMNs due to the open peer-to-peer network topology, shared wireless medium, stringent resource constraints and highly dynamic environment. These challenges clearly make a case for building multi-layer security solution that achieves both broad protection and desirable network performance. In this paper, we propose a cross-layer secure protocol for routing, data exchange and ARP problems (in case of LAN based upon WMNs). Our protocol is a ticket-based ad hoc on demand distance vector (TAODV) protocol, a secure routing protocol that is based on the design of ad hoc on demand distance vector (AODV) protocol. Due to availability of the backbone, we incorporate the authentication server (AS) for the issuance of tickets which are further used for secure routing, transfer of public keys and MAC addresses in one single step. With the transfer of public keys, source and destination can easily generate their shared secret key based upon fixed Diffie-Hellman key exchange protocol for data encryption and decryption. Our protocol is secure against both active and passive attacks.

In wireless municipal mesh (muni mesh) networks, a client station needs to associate with a mesh access point (MAP) in order to access the network. The end-to-end performance of a station depends on the access link quality between the station and the associated MAP as well as the multi-hop path quality from the associated MAP to the Internet gateway. However conventional association mechanisms used for single-hop WLANs assume that the wireless access link is the bottleneck and do not take the backhaul conditions into account, which may result in poor performance in muni mesh networks. In this paper, we propose a new joint MAP association mechanism for muni mesh networks to achieve optimal end-to-end communication performance from the station to the gateway. A station associates to one of its nearby MAPs by jointly considering the transmission capability of the access link and the backhual path. In addition, we design a new metric, called CAETT, to measure the access link quality. Different from previously proposed link metrics, CAETT takes into account the impact of 802.11 MAC layer contention on bandwidth sharing among the stations with multi-rate capability. It yields more accurate link throughput estimation. Furthermore, in order to reduce the association time, we develop an analytical model and propose a hybrid measurement/estimation method to enable a station to quickly determine the CAETT. We evaluate the performance of our system through simulations and demonstrate that the proposed joint association mechanism with the CAETT metric can greatly improve the end-to-end performance for the stations.

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

Software Defined Networking (SDN) has emerged as a new paradigm that highly increase the network management flexibility through simple but powerful abstractions. The key idea is decoupling the control plane, which makes the forward decisions, from the data plane, which effectively makes the forward. However, the OpenFlow, the main SDN enabler, is designed mainly by wired networks characteristics. As consequence, Wireless Mesh Networks (WMNs) is not suitable for operating as control plane and many wireless networks features are neglected in the OpenFlow, e.g.: power control and network ID. In addition, there are few effort research to extend SDN to wireless networks and these existing works focus on very specific issues of this integration. In this paper, we propose an architecture to extent the OpenFlow functionalities in order to proper deal with wireless networks, including an approach for transporting the control plane over wireless multihop networks. The extensions include new rules, actions, and commands, which bring the network management flexibility to the wireless context. We validated our proposal by implementing and testing some extensions in a small real world testbed. As a proof of concept, we illustrate the OpenFlow capability of isolation between research and production traffics in a wireless backhaul.

Currently deployed Wireless Mesh Networks (WMNs) are mostly hybrid, i.e., some Mesh Points (MPs) also employ additional Access Point (AP) radios to connect non-mesh stations (STAs). Today's Wi-Fi security protocols are unsuited in the use case of WMNs, as they can neither derive key material without central authentication servers nor tolerate compromised MPs, as it is required in outdoor deployments. To establish high security standards while embracing the distributed nature of WMNs, we need a novel security architecture, that does not rely on central entities and protects traffic between MPs with End-to-End Encryption (E2EE). We propose and evaluate a distributed security architecture for WMNs with attached APs, which uses certificates early in the authentication process. The architecture provides E2EE between MPs and authentic MAC addresses of all STAs and MPs. STAs, e.g., resource constrained Internet of Things (IoT) devices, cannot participate in the end-to-end encryption, but need to be securely attached to the WMN with mobility and other requirements in mind. The evaluation in our Wi-Fi testbed shows the authentication protocol's suitability for fast (re-)authentication in mobile scenarios.

Wireless multi-hop mesh network (Wireless Mesh Network, WMN), is a new network technology developed from mobile Ad hoc, widely used in the world. The paper carried out in-depth research and outlook to the key technologies, network architecture, performance and characteristics and typical application scenarios of Wireless Mesh Network.

The goal of this contribution is to show which practical routing approach, for wireless mesh network (WMN) backhaul, is the best for systems presenting a constraint on the total power to be emitted be network nodes by modeling rounting as a power allocation problem. We consider at first multiple-input multiple-output (MIMO) point-to-point capacity-achieving codes, and nodes cooperation. Furthermore we take care of a WMN backhaul with a single source node, a single destination node, and N-l intermediate nodes placed equidis-tantly on a line between them. Additionally we consider also an interference cancellation able to enhance throughput and we compare the single-hop paradigm with multi-hop one.

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 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.

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 expected higher complexity of upcoming 5G wireless backhauls suggests the need to evolve towards a softwaredefined networking (SDN) paradigm to increase the degree of programmability of these networks. Within the context of softwaredefined wireless backhaul, one important issue is the provision of an even resource consumption of both network and IT resources. Backpressure policies have shown their ability to balance resource consumption in traditional (non-SDN) wireless backhauls. This paper analyzes two use cases in which backpressure policies can be integrated in software-defined wireless backhaul to manage network and IT resources. The first use case proposes an SDN application based on a centralized backpressure policy to balance network resources in the wireless backhaul. Simulation results reveal how the granularity of routing decisions in the SDN application significantly affects the data plane performance, suggesting a trade-off between data plane performance and overload in the control plane. The second use case proposes a distributed backpressure policy to deal with the management of computing resources by balancing the processing load caused by OpenFlow (OF) switch requests among the available distributed SDN controllers. Simulation results demonstrate how a dynamic and distributed backpressure policy can balance the processing load amongst different SDN controllers, hence, leading to significant improvements with respect to static mapping policies.

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.