Toward an Access Infrastructure for Mobile Cloud

Wireless mesh networks (WMNs) are gaining significant momentum as a promising technology for the next-coming state-of-the-art wireless networking. Among many factors, the performance of WMNs would be largely affected by the properness of the deployed routing protocols and the efficient usage of wireless resources. Routing protocols are required to well capture WMNs' features while wireless channels should be used efficiently in order to accommodate high amount of traffics over the mesh backbone. Recently, a Tree-based Routing (TBR) protocol become a popular state-of-the-art proactive routing protocol and its tree-based broadcasting become an often used technique. Though TBR protocol is well-suited for WMNs' architecture and the skewed nature of traffic toward the root, the protocol in its current form faces issues which has to be addressed. Specifically, when some or all nodes are equipped with multiple radios, to reduce collision and co-channel interference, not only the parent-child relationship but also the sibling relationship need to be constructed by the TBR protocol in the multi-channel WMNs. In this paper, we propose a hybrid tree-based protocol for concurrent routing and channel assignment over WMNs. The protocol makes use of sibling links to mitigate the aforementioned shortcomings of TBR protocol. Moreover, in order to address high backbone traffic, the protocol integrates a receiver-based channel assignment scheme. The protocol efficiently deploys the parent-child topological relationships of nodes to enhance efficiency of broadcast transmissions over receiver-based multi-channel WMNs. Simulation results over NS-2 network simulator reveal that our proposed hybrid tree-based protocol achieves much higher performance than the utilization of the original receiver-based CA and TBR protocol.

As an inexpensive, scalable internet-access network, a wireless internet-access mesh network ( WIMNET ) is composed of multiple access-points ( APs ) connected by wireless links. WIMNET can improve the dependability to link or AP failures by allocating APs redundantly in the network field. Because redundant APs may increase the operational cost and degrade the performance due to increasing radio interferences, only the necessary APs for communications between the hosts and the internet gateway should be activated in conventional situations. Previously, we proposed an active AP selection algorithm to select the minimum number of APs to be activated such that the overall throughput is maximised, assuming that every link has the same constant speed. However, our preliminary experiments for the emerging high-speed IEEE802.11n protocol that should be introduced into WIMNET, found that this speed is greatly affected by the link environment such as the distance. In this paper, we present an extension of the active AP selection algorithm to efficiently select active APs under link speed changes. Besides, we extend the routing tree algorithm used in the algorithm procedure and the WIMNET simulator for throughput evaluations. We verify the effectiveness through extensive simulations in three instances.

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

Wireless Mesh Networks (WMNs) is an emerging wireless technology which attracts more and more the attention not only of service providers and enterprises, but also researchers and academicians. In this paper, we are interested by the specification and the analysis of the Channel Assignment process to improve WMNs capacities during the routing process. We give an algorithmic solution showing how to bind each radio interface to a channel, while maintaining network connectivity, in order to reduce the interference problem. Since traditional analysis approaches, based on simulation and test bed experiments still remain limited, we lean on formal methods to give a precise semantics to Wireless Mesh Networks (WMNs) and verify formally the suggested protocol. We combine logical reflection of Maude language and hierarchical structure of the Bigraphical Reactive Systems for modeling and analyzing WMNs. We define a bigraphical model having two separate roots. Networks and their paths are represented as nodes of the topology root, and channels with their eventual interferences represent the sharing nodes belonging to another root. Besides, parametric reaction rules define possible evolution and reconfiguration of these WMN entities. This obtained model is finally executed and analyzed under Maude system.

Wireless Mesh Networks (WMNs) are gaining popularity in many application areas because of their low cost and high flexibility. Technically, a WMN forms a distributed network-centric system which aims to provide communication services to the application layer, but has no built-in dependability provisions. To make the network dependable, many problems have to be solved on different layers. With this paper, we describe our ongoing work to provide an integrated solution to increase the dependability of WMNs. Our approach combines network coverage planning on the physical layer, bandwidth management on the link layer and live network monitoring to improve the reliability, availability and maintainability of a WMN. We provide fine-grained means to improve the predictability of the network components, thus making the WMN more dependable. In this paper, we present first results of our work, and describe how they are interleaved.

Real-world deployments of low-cost, peer-to-peer Wireless Mesh Networks (WMNs) for communication in under-served settings are hampered by low throughput capacity and high complexity of network control. We present an autonomic smart-agent based WMN design that organizes a node placement (NP) into dynamic network partitions to promote the WMNs’ capacity through increased frequency diversity and advanced network control. Through a custom-built simulation framework that supports agent decision making under real concurrency settings, we show that our smart partitioning technique achieves fast convergence to stable partition sets, relying on local information, under extreme node churn conditions. The design is robust to the average WMN NP density and produces partitions isolated at the physical and link layers with the properties of bounded diameter and node degree, and elected partition control node.

Channel assignment has been extensively researched for multi-radio wireless mesh networks, but it is still very challenging when it comes to its implementation. In this paper we propose a semi-dynamic and distributed channel assignment mechanism called SICA that uses game theory. To the best of our knowledge this is the first game formulation of channel assignment which takes the co-channel interference into account. SICA is an interference aware, distributed channel assignment which preserves the network connectivity without relying on a common channel nor central node for coordination between mesh routers. SICA applies an on-line learner algorithm which assumes that nodes do not have perfect information. We have simulated SICA and compared against another interference-aware channel assignment mechanism proposed in the literature called Urban-X. Simulation results show that SICA outperforms Urban-X, even using fewer radio interfaces per node.

Wireless Mesh Network (WMN) is a multi hop low cost, with easy maintenance robust network providing reliable service coverage. WMNs consist of mesh routers and mesh clients. In this architecture, while static mesh routers form the wireless backbone, mesh clients access the network through mesh routers as well as directly meshing with each other. Different from traditional wireless networks, WMN is dynamically self-organized and self-configured. In other words, the nodes in the mesh network automatically establish and maintain network connectivity. Over the years researchers have worked, to reduce the redundancy in broadcasting packet in the mesh network in the wireless domain for providing reliable service coverage, the source node deserves to broadcast or flood the control packets. The redundant control packet consumes the bandwidth of the wireless medium and significantly reduces the average throughput and consequently reduces the overall system performance. In this paper I study the optimization problem in Wireless Mesh Networks. We have proposed a novel approach to reduce the broadcast redundant packet in the wireless mesh network. Also we have shown, a novel procedure to forward the control packet to the destination nodes and efficiently minimize the transmitted control packet in the wireless mesh cloud , that covers the domain.

Capacity bounds of deployment concepts for Wireless Mesh Networks

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.

A major barrier for the adoption of wireless mesh networks is severe limits on throughput. Many in-network packet mixing techniques at the network layer [1], [2], [3] as well as the physical layer [4], [5], [6] have been shown to substantially improve throughput. However, the optimal mixing algorithm that maximizes throughput is still unknown. In this paper, we propose iPack, an algorithm for in-network generation of composite packets that integrates coding at two different layers of the protocol stack: XOR-based network coding and physical layer superposition coding. Using extensive simulations, we find that the throughput gain of the joint coding iPack algorithm is 30% more than the better performer of network coding and superposition coding in a wide range of scenarios, and automatically takes advantage of the best available coding opportunities. In a typical wireless mesh network when more traffic is between the clients and access points, the average throughput improvement of iPack, our joint optimization scheduler, can be 324%, while there can be little gain (less than 10%) if network coding alone is used. We also validate our results by implementing iPack on a small-scale testbed based on GNU Radio.

The wireless mesh network (WMN) is an economical low-power solution to provide wireless broadband access in intelligent transportation systems (ITSs). This paper investigates how to deploy access points (APs) to improve throughput and quality-of-service (QoS), when the multihop communication is used to extend the coverage of wireless ITS network. Frequency planning is suggested to improve the capacity with QoS provisioning and to make the system more scalable. To investigate the overall tradeoffs among QoS, throughput, and coverage, we develop an analytical model to evaluate throughput, frame delay, and jitter for the considered ITS WMN using the carrier-sense multiple-access (CSMA) medium access control (MAC) protocol. Then, we apply an optimization approach to determine the optimal separation distances between APs with the delay requirement. To provide a guideline for network planning, we compare the uniform-spacing and increasing-spacing AP deployment strategies. The uniform-spacing strategy is to make all the APs with the same separation distance. In the increasing-spacing strategy, the separation distances between APs are increased from the central AP to the outer APs. Because of the shorter separation distance, the AP closer to the central AP can deliver higher traffic. It is shown that the increasing-spacing strategy outperforms the uniform-spacing strategy in terms and a profit function, considering the capacity and the total cost for deploying APs.

: Wireless mesh networks (WMNs) are interconnected systems of wireless access points (APs) that provide untethered network connectivity for a group of users who require data, voice, and/or video communication. The wireless access medium of a WMN makes it particularly vulnerable to attack and exploitation. We seek a method for quickly designing WMN physical topologies (i.e., the placement of APs) that are robust to the effects of electromagnetic jamming. The conflicting interests of a network designer and attacker in respectively maximizing and minimizing network performance make this problem a natural candidate for the use of game theory. We apply the game theoretic defender-attacker-defender (DAD) methodology to the simultaneous routing, resource allocation, and coverage (SRRA+C) model of WMN performance to simulate the design, attack, and operation of a WMN. Our algorithm and associated decision-support tool can quickly prescribe jamming-robust WMN topologies that minimize the worst possible damage that an adversary can inflict. Our approach considers radio-operating characteristics, the relative importance of client coverage and network flow, and the effects of radio propagation over terrain. To our knowledge, we are the first to use an algorithm with proven global convergence to design jamming-robust WMNs, and the first to apply the DAD framework to the problem of WMN design.

Wireless Mesh Networks (WMNs) have many advantages such as low cost and increased high speed wireless Internet connectivity, therefore WMNs are becoming an important networking infrastructure. In our previous work, we implemented a Particle Swarm Optimization (PSO) based simulation system for node placement in WMNs, called WMN-PSO. Also, we implemented a simulation system based on Simulated Annealing (SA) for solving node placement problem in WMNs, called WMN-SA. In this paper, we implement a hybrid simulation system based on PSO and SA, called WMN-PSOSA. We evaluate the performance of WMN-PSOSA by conducting computer simulations considering Exponential and Weibull distributions. Simulation results show that WMN-PSOSA performs better for Weibull distribution compared with the case of Exponential distribution.

Wireless Mesh Networks (WMNs) have many advantages such as low cost and increased high speed wireless Internet connectivity, therefore WMNs are becoming an important networking infrastructure. In our previous work, we implemented a Particle Swarm Optimization (PSO) based simulation system for node placement in WMNs, called WMN-PSO. Also, we implemented a simulation system based on Simulated Annealing (SA) for solving node placement problem in WMNs, called WMN-SA. In this paper, we implement a hybrid simulation system based on PSO and SA, called WMN-PSOSA. We evaluate the performace of WMN-PSOSA by conducting computer simulations considering Constriction Method (CM) and Linearly Decreasing Vmax Method (LDVM). The simulation results show that the LDVM has better performace than CM for this scenario.