Results 11 - 20
of
114
Evaluation of MultiRadio Extensions to AODV for Wireless Mesh Networks
- Proceedings of the 4th ACM International Workshop on Mobility Management and Wireless Access (MobiWac
, 2006
"... Due to their self-configuring and self-healing capabilities, as well as their low equipment and deployment cost, Wire-less Mesh Networks (WMNs) based on commodity hardware present a promising technology for a wide range of applica-tions. Currently, one of key challenges that WMN technol-ogy faces is ..."
Abstract
-
Cited by 15 (5 self)
- Add to MetaCart
(Show Context)
Due to their self-configuring and self-healing capabilities, as well as their low equipment and deployment cost, Wire-less Mesh Networks (WMNs) based on commodity hardware present a promising technology for a wide range of applica-tions. Currently, one of key challenges that WMN technol-ogy faces is the limited capacity and scalability due to high levels of interference, which is typical for multi-hop wire-less networks. A simple and relatively low-cost approach to address this problem that has recently been proposed is the use of multiple wireless network interfaces (radios) per node. Operating the radios on each node on different, non-overlapping channels allows making more efficient use of the radio spectrum and thereby reducing interference and con-tention. In this paper, we evaluate the performance of the Ad-hoc On-demand Distance Vector (AODV) routing pro-tocol in a Multi-Radio Wireless Mesh Network. Our simu-lation results show that under high traffic load conditions, Multi-Radio AODV (AODV-MR) is able to efficiently uti-lize the increased spectrum, and proves to be far superior to single radio AODV. We therefore believe that AODV-MR is a promising candidate for multi-radio WMNs.
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.
Context-based Routing: Techniques, Applications and Experience
"... Routing protocols in multi-hop networks typically find low cost paths by modeling the cost of a path as the sum of the costs on the constituting links. However, the insufficiency of this approach becomes more apparent as new lower layer technologies are incorporated. For instance, to maximize the be ..."
Abstract
-
Cited by 14 (0 self)
- Add to MetaCart
(Show Context)
Routing protocols in multi-hop networks typically find low cost paths by modeling the cost of a path as the sum of the costs on the constituting links. However, the insufficiency of this approach becomes more apparent as new lower layer technologies are incorporated. For instance, to maximize the benefit of multiple radios, ideally we should use routes that contain low interference among the constituting links. Similarly, to maximize the benefit of network coding, we should ideally use routes that create more coding opportunities. Both of these are difficult to accomplish within the conventional routing framework because therein the links are examined in isolation of each other, whereas the nature of the problem involves interdependencies among the links. This paper aims at revealing a unifying framework for routing in the presence of inherent link interdependencies, which we call “context-based routing”. Through the case studies of two concrete application scenarios in wireless networks, network coding–aware routing and self-interference aware routing in multi-radio systems, we highlight the common key pillars for context-based routing and their interplay: a context-based path metric and a route selection method. We implement contextbased routing protocols in Windows XP and Linux and evaluate them in detail. Experiments conducted on 2 testbeds demonstrate significant throughput gains. 1
Distributed Strategies for Channel Allocation and Scheduling in Software-Defined Radio Networks
"... Abstract—Equipping wireless nodes with multiple radios can significantly increase the capacity of wireless networks, by making these radios simultaneously transmit over multiple nonoverlapping channels. However, due to the limited number of radios and available orthogonal channels, designing efficie ..."
Abstract
-
Cited by 14 (3 self)
- Add to MetaCart
(Show Context)
Abstract—Equipping wireless nodes with multiple radios can significantly increase the capacity of wireless networks, by making these radios simultaneously transmit over multiple nonoverlapping channels. However, due to the limited number of radios and available orthogonal channels, designing efficient channel assignment and scheduling algorithms in such networks is a major challenge. In this paper, we present provablygood distributed algorithms for simultaneous channel allocation of individual links and packet-scheduling, in Software-Defined Radio (SDR) wireless networks. Our distributed algorithms are very simple to implement, and do not require any coordination even among neighboring nodes. A novel access hash function or random oracle methodology is one of the key drivers of our results. With this access hash function, each radio can know the transmitters ’ decisions for links in its interference set for each time slot without introducing any extra communication overhead between them. Further, by utilizing the inductivescheduling technique, each radio can also backoff appropriately to avoid collisions. Extensive simulations demonstrate that our bounds are valid in practice. I.
Cooperative caching in wireless p2p networks: Design, implementation, and evaluation
- IEEE Transactions on Parallel and Distributed Systems
"... Abstract—Some recent studies have shown that cooperative cache can improve the system performance in wireless P2P networks such as ad hoc networks and mesh networks. However, all these studies are at a very high level, leaving many design and implementation issues unanswered. In this paper, we prese ..."
Abstract
-
Cited by 14 (4 self)
- Add to MetaCart
(Show Context)
Abstract—Some recent studies have shown that cooperative cache can improve the system performance in wireless P2P networks such as ad hoc networks and mesh networks. However, all these studies are at a very high level, leaving many design and implementation issues unanswered. In this paper, we present our design and implementation of cooperative cache in wireless P2P networks, and propose solutions to find the best place to cache the data. We propose a novel asymmetric cooperative cache approach, where the data requests are transmitted to the cache layer on every node, but the data replies are only transmitted to the cache layer at the intermediate nodes that need to cache the data. This solution not only reduces the overhead of copying data between the user space and the kernel space, it also allows data pipelines to reduce the end-to-end delay. We also study the effects of different MAC layers, such as 802.11-based ad hoc networks and multi-interface-multichannel-based mesh networks, on the performance of cooperative cache. Our results show that the asymmetric approach outperforms the symmetric approach in traditional 802.11-based ad hoc networks by removing most of the processing overhead. In mesh networks, the asymmetric approach can significantly reduce the data access delay compared to the symmetric approach due to data pipelines. Index Terms—Wireless networks, P2P networks, cooperative cache. Ç
A learning-based approach for distributed multi-radio channel allocation in wireless mesh networks
- in ICNP
, 2009
"... Abstract—We consider the distributed channel allocation problem in IEEE 802.11-based multi-radio wireless mesh networks. We develop a new scalable protocol termed LCAP for efficient and adaptive distributed multi-radio channel allocation. In LCAP, nodes autonomously learn their channel allocation ba ..."
Abstract
-
Cited by 10 (1 self)
- Add to MetaCart
(Show Context)
Abstract—We consider the distributed channel allocation problem in IEEE 802.11-based multi-radio wireless mesh networks. We develop a new scalable protocol termed LCAP for efficient and adaptive distributed multi-radio channel allocation. In LCAP, nodes autonomously learn their channel allocation based on neighborhood and channel usage information, which is obtained via a novel neighbor discovery protocol that enables neighboring nodes to efficiently discover each other even when they do not share a common channel. Extensive simulation-based evaluation of LCAP relative to the state-of-the-art Asynchronous Distributed Coloring (ADC) protocol demonstrates that LCAP is able to achieve its stated objectives of efficient channel utilization across diverse traffic patterns, protocol scalability and adaptivity to factors such as external interference. We also present a prototype implementation of the LCAP neighbor discovery module that is key to implementing the proposed approach. I.
Hybrid Mesh Ad-hoc On-demand Distance Vector Routing Protocol”, Australian Computer Science Conference (ACSC
- Stuckey P.J, Codish M. “Propagation = Lazy Clause Generation”, 13th International Conference on Principles and Practice of Constraint Programming
"... Wireless Mesh Networks (WMNs) have recently gained increasing attention and have emerged as a technology with great potential for a wide range of applications. WMNs can be considered as a superset of traditional mobile ad-hoc networks (MANETs), where the network is comprised of mobile client devices ..."
Abstract
-
Cited by 10 (4 self)
- Add to MetaCart
(Show Context)
Wireless Mesh Networks (WMNs) have recently gained increasing attention and have emerged as a technology with great potential for a wide range of applications. WMNs can be considered as a superset of traditional mobile ad-hoc networks (MANETs), where the network is comprised of mobile client devices (MESH CLIENTs). In addition to MESH CLIENTs, a WMN can also contain relatively static devices called mesh routers (MESH ROUTERs). Such hybrid WMNs are characterized by a high level of heterogeneity, since static MESH ROUTERs are typically much less resource constrained than mobile MESH CLIENTs, and are also often equipped with multiple radio interfaces. Traditional ad-hoc routing protocols do not differentiate between these types of nodes and therefore cannot achieve optimal performance in hybrid WMNs. In this paper, we propose simple extensions to the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which aim to take advantage of the heterogeneity in hybrid WMNs by preferentially routing packets via paths consisting of high capacity MESH ROUTERs. In addition, we implement a simple channel selection scheme that reduces interference and maximizes channel diversity in multi-radio WMNs. Our simulation results show that in hybrid WMNs, our extensions result in significant performance gains over the standard AODV protocol.
System Architecture for Multichannel Multi-interface Wireless Networks
, 2006
"... Wireless ad hoc networks typically make use of a single radio interface on a fixed channel to communicate with neighboring nodes. Previous research has advocated the use of multiple wireless channels for enhancing the capacity of such networks. IEEE 802.11 based wireless network interfaces are capab ..."
Abstract
-
Cited by 9 (1 self)
- Add to MetaCart
(Show Context)
Wireless ad hoc networks typically make use of a single radio interface on a fixed channel to communicate with neighboring nodes. Previous research has advocated the use of multiple wireless channels for enhancing the capacity of such networks. IEEE 802.11 based wireless network interfaces are capable of communicating over multiple nonoverlapping channels. In existing system architectures the use of multiple channels can be supported provided every channel has one dedicated interface. However, in many scenarios, hosts will be equipped with fewer interfaces than available channels, requiring interfaces to be switched between channels. Implementing protocols, which require frequent switching, is nontrivial. In this thesis, we developed a system that supports the implementation of protocols which require frequent switching. Initially, the feasibility of implementing such protocols using currently available wireless interfaces and system software was studied. The feasibility study identified several short comings in present day operating systems for implementing multichannel protocols. We developed a system for the Linux kernel which can handle these short comings. Our system includes modifications to the wireless interface device drivers that improve performance of multichannel protocols. We discuss the details of the modifications made to the device driver used in our testbed. Following this, an example multichannel multi-interface protocol interaction with our system is presented. Finally, the performance of our system is analyzed, and suggestions for selecting system parameters are made. ii To my Parents, Grandparents, Hari and Suma iii ACKNOWLEDGMENTS This thesis would not have been possible without the support of my adviser, Dr. Nitin Vaidya, my family members, and friends. I would also like to acknowledge my fellow researcher and friend, Pradeep Kyasanur, who has helped me in every stage of my research. I also acknowledge National Science Foundation (NSF) for financially supporting my
Protocol Design Challenges for Multi-hop Dynamic Spectrum Access Networks
- In Proc. of DySPAN’05
, 2005
"... Abstract — Driven by the need to improve network capacity, there is a growing interest for dynamically utilizing spectrum over a wide range of frequency bands. The available spectrum is typically divided into multiple channels. Past work on designing protocols for multi-channel wireless networks has ..."
Abstract
-
Cited by 9 (1 self)
- Add to MetaCart
Abstract — Driven by the need to improve network capacity, there is a growing interest for dynamically utilizing spectrum over a wide range of frequency bands. The available spectrum is typically divided into multiple channels. Past work on designing protocols for multi-channel wireless networks has assumed that all channels are homogeneous. However, channels that are located in widely separated frequency bands exhibit considerable heterogeneity in transmission ranges, data rates, etc. In this paper, we identify the impact of channel heterogeneity on network performance, and motivate the need to account for channel heterogeneity while designing higher layer protocols. We present some approaches for managing heterogeneity, and propose hiding most of the channel heterogeneity from higher layers by designing suitable channel abstractions. I.
Mesh networking protocols to exploit physical layer capabilities
- Proc. IEEE Workshop on Wireless Mesh Networks (WiMesh
, 2005
"... Abstract — Wireless mesh networks are becoming increasingly popular as a low-cost alternative to wired networks for providing high-speed last mile connectivity. A key challenge in mesh networks is the need for sufficient network capacity to meet the requirements of applications, especially when netw ..."
Abstract
-
Cited by 7 (1 self)
- Add to MetaCart
(Show Context)
Abstract — Wireless mesh networks are becoming increasingly popular as a low-cost alternative to wired networks for providing high-speed last mile connectivity. A key challenge in mesh networks is the need for sufficient network capacity to meet the requirements of applications, especially when network density increases over time, and newer applications require higher throughputs. In this paper, we consider some approaches for improving network capacity by exploiting various physical layer capabilities. Specifically, we consider the use of multiple wireless channels, and improving utilization of any given channel by introducing “spatial backoff”, for improving network capacity. Through these example scenarios, we highlight the challenges involved and benefits possible by exploiting physical layer capabilities in mesh networks. I.
