Results 1 - 10
of
15
Capacity of Multi-Channel Wireless Networks with Random (c, f) Assignment
, 2007
"... With the availability of multiple unlicensed spectral bands, and potential cost-based limitations on the capabilities of individual nodes, it is increasingly relevant to study the performance of multichannel wireless networks with channel switching constraints. To this effect, some constraint models ..."
Abstract
-
Cited by 275 (11 self)
- Add to MetaCart
(Show Context)
With the availability of multiple unlicensed spectral bands, and potential cost-based limitations on the capabilities of individual nodes, it is increasingly relevant to study the performance of multichannel wireless networks with channel switching constraints. To this effect, some constraint models have been recently proposed, and connectivity and capacity results have been formulated for networks of randomly deployed single-interface nodes subject to these constraints. One of these constraint models is termed random (c, f) assignment, wherein each node is pre-assigned a random subset of f channels out of c (each having bandwidth W c), and may only switch on these. Previous results for this model established bounds on network capacity, and proved that when c = O(logn), the per-prnd f flow capacity is O(W nlogn) and Ω(W cnlogn) (where prnd = 1 −(1 − f f f f 2 c)(1 − c−1)...(1 − c − f+1) ≥ 1 − e − c). In this paper we present a lower bound construction that matches the previous upper prnd bound. This establishes the capacity as Θ(W nlogn). The surprising implication of this result is that when f = Ω ( √ c), random (c, f) assignment yields capacity of the same order as attainable via unconstrained switching. The routing/scheduling procedure used by us to achieve capacity requires synchronized route-construction for all flows in the network, leading to the open question of whether it is possible to achieve capacity using asynchronous procedures.
Designing routing metrics for mesh networks
- In WiMesh
, 2005
"... Abstract — Designing routing metrics is critical for performance in wireless mesh networks. The unique characteristics of mesh networks, such as static nodes and the shared nature of the wireless medium, invalidate existing solutions from both wired and wireless networks and impose unique requiremen ..."
Abstract
-
Cited by 106 (1 self)
- Add to MetaCart
(Show Context)
Abstract — Designing routing metrics is critical for performance in wireless mesh networks. The unique characteristics of mesh networks, such as static nodes and the shared nature of the wireless medium, invalidate existing solutions from both wired and wireless networks and impose unique requirements on designing routing metrics for mesh networks. In this paper, we focus on identifying these requirements. We first analyze the possible types of routing protocols that can be used and show that proactive hop-by-hop routing protocols are the most appropriate for mesh networks. Then, we examine the requirements for designing routing metrics according to the characteristics of mesh networks and the type of routing protocols used. Finally, we study several existing routing metrics, including hop count, ETX, ETT, WCETT and MIC in terms of their ability to satisfy these requirements. Our simulation results of the performance of these metrics confirm our analysis of these metrics. I.
Resource allocation in multi-radio multi-channel multi-hop wireless networks
- IEEE INFOCOM 2008
, 2008
"... Abstract—A joint congestion control, channel allocation and scheduling algorithm for multi-channel multi-interface multi-hop wireless networks is discussed. The goal of maximizing a utility function of the injected traffic, while guaranteeing queues stability, is defined as an optimization problem w ..."
Abstract
-
Cited by 22 (0 self)
- Add to MetaCart
(Show Context)
Abstract—A joint congestion control, channel allocation and scheduling algorithm for multi-channel multi-interface multi-hop wireless networks is discussed. The goal of maximizing a utility function of the injected traffic, while guaranteeing queues stability, is defined as an optimization problem where the input traffic intensity, channel loads, interface to channel binding and transmission schedules are jointly optimized by a dynamic algorithm. Due to the inherent NP-Hardness of the scheduling problem, a simple centralized heuristic is used to define a lower bound for the performance of the whole optimization algorithm. The behavior of the algorithm for different numbers of channels, interfaces and traffic flows is shown through simulations. I.
N.: Net-X: System eXtensions for Supporting Multiple Channels, Multiple Radios, and Other Radio Capabilities
, 2006
"... Abstract — There are several interface capabilities that may be available in next generation wireless networks. Some examples of interface capabilities include the ability to set the channel of operation and data rate on a frequent basis, and the ability to equip devices with multiple radio interfac ..."
Abstract
-
Cited by 14 (3 self)
- Add to MetaCart
(Show Context)
Abstract — There are several interface capabilities that may be available in next generation wireless networks. Some examples of interface capabilities include the ability to set the channel of operation and data rate on a frequent basis, and the ability to equip devices with multiple radio interfaces and multiple antennas. It may be possible to significantly improve the performance of wireless networks by exploiting the interface capabilities through carefully designed protocols. However, current operating systems have poor support for implementing protocols that need to use the available interface capabilities. The goal of the Net-X project is to develop operating system support for utilizing interface capabilities. As a first step in this direction, we have developed an architecture in Linux to support the use of multiple channels, multiple interfaces, and interface switching. This support has been used to implement a set of multichannel protocols that we had previously developed. In this report, we will describe the new architectural support, implementation of the multichannel protocols, and the use of the protocols in a mesh network. We also describe how the architecture may be extended to support the use of other interface capabilities as well. I.
Experiments on a multichannel multi-interface wireless network
- in M.S. Thesis, ECE Dept., UIUC
, 2008
"... Wireless mesh network technology provides a quick method of providing network access. Traditional wireless mesh networks face problems regarding spatial reuse. The simultaneous use of multiple interfaces and channels attempts to solve this problem. Support for these multiple channels and devices has ..."
Abstract
-
Cited by 4 (0 self)
- Add to MetaCart
Wireless mesh network technology provides a quick method of providing network access. Traditional wireless mesh networks face problems regarding spatial reuse. The simultaneous use of multiple interfaces and channels attempts to solve this problem. Support for these multiple channels and devices has been implemented through the Net-X system. Performance of the network depends on the amount of cross channel interference because wireless transmissions use a shared medium and interfere with each other unless properly separated in distance and frequency. We test the interference experienced in single, dual, and triple interface nodes. A protocol needs to support the most common types of TCP and UDP traffic for it to be useful. One popular type of UDP traffic is that of voice over internet (VoIP). VoIP traffic is more demanding on a network connection, but we find that the protocol is able to support its requirements for one and two-hop traffic. We propose a delay reduction scheme to reduce the delay caused by the frequent channel switching. Another method of increasing performance of the network is to utilize more interfaces. The current implementation of the testbed uses two interfaces per node. Adding a third interface will require some changes in the hybrid multichannel protocol. Experiments show that multihop TCP transfers benefit from this added interface. Based on these experiments, we propose some ideas that can be used in future multichannel work. I.
PERFORMANCE OF WIRELESS NETWORKS SUBJECT TO CONSTRAINTS AND FAILURES
, 2008
"... Recent years have seen a proliferation in the use of wireless multi-hop networks in diverse scenarios ranging from community mesh networks to wireless sensor networks. As wireless networks find application in such wide-ranging arenas and are deployed at large scale, they will increasingly need to op ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
Recent years have seen a proliferation in the use of wireless multi-hop networks in diverse scenarios ranging from community mesh networks to wireless sensor networks. As wireless networks find application in such wide-ranging arenas and are deployed at large scale, they will increasingly need to operate in the presence of heterogeneous, and often constrained, hardware capabilities. Furthermore, fault-tolerant communication algorithms will be required to provide the building blocks for reliable operation in the face of failure and/or disruption. In this dissertation, we have investigated performance and fault-tolerance issues in networks of such wireless devices. We have studied two specific problem domains, viz., throughput performance in multi-channel wireless networks where devices have heterogeneous and constrained channel switching capabilities, and feasibility of fault-tolerant broadcast in single channel wireless networks where devices can exhibit Byzantine or crash-stop failure.
c ○ 2007 by Rishi Bhardwaj. All rights reserved. LESSONS FROM A MULTICHANNEL WIRELESS MESH NETWORK BY
"... Wireless Mesh Networks offer a quick, easy and cost efficient solution to providing network connectivity. Mesh networks would be required to support high data rate in order to compete with other more conventional Ethernet based network solutions. The usage of multiple frequency channels and multiple ..."
Abstract
- Add to MetaCart
(Show Context)
Wireless Mesh Networks offer a quick, easy and cost efficient solution to providing network connectivity. Mesh networks would be required to support high data rate in order to compete with other more conventional Ethernet based network solutions. The usage of multiple frequency channels and multiple interfaces at each wireless mesh node has been proposed earlier to increase the capacity of such networks. In this thesis we evaluate such a mesh network implementation where each node in the network is equipped with two wireless radio interfaces and uses multiple channels for transmission. The network employs a hybrid multichannel protocol which provides connectivity between nodes with multiple interfaces using multiple channels. The protocol is implemented on top of the Net-X system architecture. The Net-X framework provides support for frequent channel switching on an interface which is required by the hybrid multichannel protocol, with certain channel switching delay overheads added. We look at the throughput improvements achieved for a single flow and for concurrent multiple flows in the multi-channel network as opposed to using a single channel in the network. We identify problems arising from the usage of multiple channels for concurrent transmissions in close range and discuss the effects of channel switching delay on the network. We propose certain changes in the Multi-Channel Routing (MCR) metric used by the hybrid multichannel protocol to address these problems. We then evaluate the throughput
c ○ Copyright by Yaling Yang, 2006 DISTRIBUTED RESOURCE ALLOCATION IN CONTENTION-BASED WIRELESS NETWORKS BY
"... Due to the limited bandwidth in wireless networks, careful resource allocation schemes must be used to allocate bandwidth to applications. There are two typical types of applications in wireless networks that require resource allocation: soft realtime applications and best effort applications. While ..."
Abstract
- Add to MetaCart
(Show Context)
Due to the limited bandwidth in wireless networks, careful resource allocation schemes must be used to allocate bandwidth to applications. There are two typical types of applications in wireless networks that require resource allocation: soft realtime applications and best effort applications. While soft realtime applications require QoS support for effective bandwidth utilization, best effort applications can adapt to changes in bandwidth and are more concerned about network utilization. Due to this difference in application requirements, intelligent resource allocation schemes must be used to provide the desired amount of resources to realtime flows while at the same time allocate the rest of the bandwidth to best effort flows efficiently. The goal of this thesis is to explore two different methods to support such intelligent distributed resource allocation in contention-based wireless networks. The first method uses signaling between nodes to coordinate resource allocation. The benefit of this signaling approach is that it does not require any specialized MAC layer and is based on existing scheduling algorithms used in current MAC layer protocols such as IEEE 802.11. Due to the shared nature of wireless medium, a signaling approach must effectively coordinate resource
Multi-Channel Anypath Routing for Multi-Channel Wireless Mesh Networks
"... the requirements ..."
(Show Context)
Joint Link Scheduling and Routing for Load Balancing in STDMA Wireless Mesh Networks
"... Abstract: In wireless mesh networks, it is known to be effective to use a TDMA based MAC than a contention-based CSMA. In addition, if spatial TDMA is used, network performance can be improved further because of its spatial reuse effect. However this scheme still has a disadvantage in the system per ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract: In wireless mesh networks, it is known to be effective to use a TDMA based MAC than a contention-based CSMA. In addition, if spatial TDMA is used, network performance can be improved further because of its spatial reuse effect. However this scheme still has a disadvantage in the system performance aspect without a load-balanced routing because the resource of links that are not used is wasted and frequently used links are out of resources. That is, the number of available flows in network is limited because load balancing is not performed. In this paper, we propose joint link scheduling and routing through a cross-layer scheme. For this, we propose a load balancing routing method to maximizes the minimum available resource under the given traffic pattern and scheduling method for maximizing link utilization on the given route. These two methods are iterated until an optimized solution can be obtained. The proposed algorithm can be formulated using a mathematical LP problem and we show that it is very effective for load balancing compared to simple adoption of IEEE 802.11s which is a standard TDMA protocol in wireless mesh network. If the proposed algorithm is applied to initial design solution such as Smart Grid, the number of available flows can be increased and the load on each link can be balanced.
