Wireless mesh network

About: Wireless mesh network is a research topic. Over the lifetime, 13600 publications have been published within this topic receiving 221035 citations. The topic is also known as: WMN.

An ad hoc networking scheme in hybrid networks for emergency communications

Abstract: This paper describes an ad hoc networking scheme and routing protocol for emergency communications. The objective of the network is to collect damage assessment information quickly and stably in a disaster. The network is configured with a hybrid wireless network, combining ad hoc networks and a cellular network to maintain connectivity between a base station (BS) and nodes even in a disaster. In the event that a direct link between the BS and a node is disconnected due to damage or obstacles, the node switches to the ad hoc mode, and accesses the BS via neighboring nodes by multihopping. The routing protocol proposed in this paper discovers and builds a route by way of monitoring neighbors' communications instead of broadcasting a route request packet. The network employs a dedicated medium access control protocol based on TDM (Time Division Multiplexing) for multihopping in ad hoc networks to maintain accessibility and to perform a short delay. Experiments showed that approximately 90% of nodes are capable of reaching the BS within a few hops, even in conditions where only 20% of nodes maintain direct connections to the BS. In addition, the results showed that it is feasible for the network to operate in a short delay for delivering a packet to the BS. However, throughput is not retrieved sufficiently due to the restriction of the access protocol, whereas reachability does improve sufficiently. Therefore, the network is suitable for collecting damage assessment information and transmitting urgent traffic quickly and stably, while the data is restricted to a small amount.

Topology Control and Channel Assignment in Multi-Radio Multi-Channel Wireless Mesh Networks

Abstract: The aggregate capacity of wireless mesh networks can be improved significantly by equipping each node with multiple interfaces and by using multiple channels in order to reduce the effect of interference. Efficient channel assignment is required to ensure the optimal use of the limited channels in the radio spectrum. In this paper, a cluster-based multipath topology control and channel assignment scheme (CoMTaC), is proposed, which explicitly creates a separation between the channel assignment and topology control functions, thus minimizing flow disruptions. A cluster-based approach is employed to ensure basic network connectivity. Intrinsic support for broadcasting with minimal overheads is also provided. CoMTaC also takes advantage of the inherent multiple paths that exist in a typical WMN by constructing a spanner of the network graph and using the additional node interfaces. The second phase of CoMTaC proposes a dynamic distributed channel assignment algorithm, which employs a novel interference estimation mechanism based on the average link-layer queue length within the interference domain. Partially overlapping channels are also included in the channel assignment process to enhance the network capacity. Extensive simulation based experiments have been conducted to test various parameters and the effectiveness of the proposed scheme. The experimental results show that the proposed scheme outperforms existing dynamic channel assignment schemes by a minimum of a factor of 2.

Ditto: a system for opportunistic caching in multi-hop wireless networks

Abstract: This paper presents the design, implementation, and evaluation of Ditto, a system that opportunistically caches overheard data to improve subsequent transfer throughput in wireless mesh networks. While mesh networks have been proposed as a way to provide cheap, easily deployable Internet access, they must maintain high transfer throughput to be able to compete with other last-mile technologies. Unfortunately, doing so is difficult because multi-hop wireless transmissions interfere with each other, reducing the available capacity on the network. This problem is particularly severe in common gateway-based scenarios in which nearly all transmissions go through one or a few gateways from the mesh network to the Internet.Ditto exploits on-path as well as opportunistic caching based on overhearing to improve the throughput of data transfers and to reduce load on the gateways. It uses content-based naming to provide application independent caching at the granularity of small chunks, a feature that is key to being able to cache partially overheard data transfers. Our evaluation of Ditto shows that it can achieve significant performance gains for cached data, increasing throughput by up to 7x over simpler on-path caching schemes, and by up to an order of magnitude over no caching.

Joint Topology Control and Routing in IEEE 802.11-Based Multiradio Multichannel Mesh Networks

Abstract: Due to low cost, ease of deployment, increased coverage, and enhanced capacity, multiradio mesh networks that utilize inexpensive and readily available Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless interfaces are touted as the new frontier of wireless networking. In a multihop mesh system, the close interaction between topology control and routing selection affects the system throughput of a wireless network. This paper proposes a novel joint topology control and routing (JTCR) protocol for a multiradio multichannel wireless mesh network to exploit both channel diversity and spatial reusability. It resides between medium access control and the network layer and aims to improve the network throughput by coordinating transmission power, channel assignment, and route selection among multiple nodes in a distributed way. JTCR jointly coordinates the transmission power at each node, the channel selection on each wireless interface, and the route selection among interfaces based on the traffic information that is measured and exchanged among two-hop neighbor nodes. An equivalent channel air time metric (ECATM) is presented to quantify the difference of various adjustment candidates. This protocol achieves the efficient utilization of available channels by selecting a feasible adjustment candidate with the smallest EC ATM value and coordinating affected nodes to realize the adjustment. Our NS-2-based simulation results show that the network throughput can be significantly improved by using our proposed solution.