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.

Analysis ofWiMedia-based UWB Mesh Networks

Abstract: Regarding maximum transmission rates, Ultra Wideband (UWB) seems to be the wireless technology which could successfully replace most of the data-cables in office and home environments: With up to 480 Mb/s gross data rate, wireless high-definition video streaming and data synchronization become feasible. Of course, these advantages come at a price: UWB is designed for short-range communication, limited to 10 m. While this suffices for some application, it does not fulfill the vision of ubiquitous wireless access in the fully-connected home. A straightforward solution to increase the network coverage is given by Wireless Mesh Networks (WMNs). In this paper, we analyze if the combination of UWB and WMN is able to provide the required coverage and the expected data rates. Several different deployment concepts (including ad- hoc networking and dedicated mesh relays) are evaluated with a realistic system model, which is able to compute the resulting network capacity. The results show that under the assumptions of the model, i. e. a MAC which is able to exploit spatial divided frequency reuse, UWB mesh networks are able to provide a stable capacity of more than 100 Mb/s in a typical scenario of up to 250 m2. Hence, the combination of the two technologies is able to succeed in much more application scenarios in comparison to the current UWB standard.

NCTUns network simulation and emulation for wireless resource management

Abstract: Summary This paper describes NCTUns, an innovative network simulator and emulator for wireless and mobile networks. Effects of various radio resource management and quality of service (QoS) schemes on higher-layer protocols and real-world applications can be easily studied using NCTUns. In this paper, we elaborate on NCTUns simulation methodology, architecture, design, functionalities, performance, and applications. NCTUns simulation for wireless ad hoc, sensor, inter-vehicle communication networks, GPRS cellular networks, and wireless mesh networks are also illustrated. More details about this tool can be found in http://NSL.csie.nctu.edu.tw/nctuns.html. Copyright # 2005 John Wiley & Sons, Ltd.

System and method for real-time tracking of objects

Abstract: Real-time location systems and methods use small, battery operated sensors and radios. The radios conform to the IEEE 802.15.4 standard. The radios are attached to objects to form mobile nodes. Fixed nodes are positioned to define a wired or wireless mesh network representing an area in which the objects can be monitored and tracked. The real-time location systems/methods provide robust, flexible and highly scalable systems/methods for remotely, accurately, efficiently, and/or readily tracking and securing objects (e.g., equipment, inventory, people) at a relatively low cost.

Distance-1 Constrained Channel Assignment in Single Radio Wireless Mesh Networks

Abstract: This paper addresses channel assignment and random medium access design for single-radio multi-channel mesh networks. Two prior approaches include: (i) designing MAC protocols that dynamically select channels based on local information and (ii) partitioning the mesh into subnetworks with different channels and using 802.11 as the medium access protocol. Both of these approaches suffer from limited throughput improvement; the first approach due to wrong or incomplete channel state information that inherently arises in a multi-hop wireless environment, while the second approach due to high interference within each subnetwork. In this paper, we first introduce D1C-CA, Distance-1 Constrained Channel Assignment. D1C-CA statically assigns channels to a set of links as a function of physical connectivity, contention, and the unique gateway functionality of mesh networks, i.e, all Internet (non-local) traffic has a gateway node as its source or destination. To design D1C-CA, we model the channel assignment problem as a new form of graph edge coloring in which edges at distance one are constrained. We prove that the problem is NP-complete and design an efficient heuristic solution for mesh networks. Second, we design an asynchronous control-channel-based MAC protocol that solves multi-channel coordination problems and employs the proposed channel assignment algorithm. Finally, we investigate the performance of our approach through extensive simulations and show considerable performance improvements compared to alternate schemes.

The Impact of Adjacent Channel Interference in Multi-Radio Systems using IEEE 802.11

Abstract: A promising approach for improving the capacity of Wireless Mesh Networks is by making use of multiple non-overlapping RF channels. Multi-channel protocols have the advantage that several devices can transmit in parallel within a collision domain on distinct channels. When using IEEE 802.11b/g/a most protocol designers assume 3 and 12 non-overlapping channels, respectively. However, this simplified assumption does not hold. We present results from measurements that show that the number of available non-interfering channels depends on the antenna separation, PHY modulation, RF band, traffic pattern and whether single- or multi-radio systems are used. The problem is caused by adjacent channel interference (ACI) where nearby transmitters "bleed over" to other frequencies and either cause spurious carrier sensing or frame corruption. For nearby transceivers, as in the factory defaults of multi-radio devices, this results in at most two non- interfering channels, one within 2.4 GHz and the other within the 5 GHz band. Only if the distance between the antennas is increased, non-interfering channels within the bands themselves become available. Moreover, our comparison of single- and multi- radio systems allows us to isolate ACI from board crosstalk and radiation leakage of which only the multi-radio systems seem to suffer. Finally, we show how a packet-level simulator can be improved to realistically incorporate ACI. With the help of this simulator more confident statements about the performance of various multi-channel protocols can be made.