Ad hoc wireless distribution service

About: Ad hoc wireless distribution service is a research topic. Over the lifetime, 17734 publications have been published within this topic receiving 488205 citations.

TCP-BuS: improving TCP performance in wireless ad hoc networks

Abstract: Reliable data transmission over a wireless multi-hop network, called the ad hoc network, has proven to be non-trivial. The TCP (transmission control protocol), a widely used end-to-end reliable transport protocol in a wired network, is not entirely suitable when applied to a wireless ad hoc network due to TCP's congestion control schemes. In particular, the TCP at the source considers the network as congested when detecting packet losses or timeouts. However, in a wireless ad hoc network when a route disconnection occurs because of node movement, the network mistakes this as a congestion. Therefore, the conventional TCP congestion control mechanism cannot be applied, because a route disconnection must be handled differently from a network congestion. We propose a new mechanism that improves the TCP performance in a wireless ad hoc network where each node can buffer packets during a route disconnection and reestablishment. Additionally, we incorporate new measures to deal with the reliable transmission of important control messages. Our simulation results further confirmed these advantages.

GKMPAN: an efficient group rekeying scheme for secure multicast in ad-hoc networks

Abstract: We present GKMPAN, an efficient and scalable group rekeying protocol for secure multicast in ad hoc networks. Our protocol exploits the property of ad hoc networks that each member of a group is both a host and a router, and distributes the group key to member nodes via a secure hop-by-hop propagation scheme. A probabilistic scheme based on predeployed symmetric keys is used for implementing secure channels between members for group key distribution. GKMPAN also includes a novel distributed scheme for efficiently updating the predeployed keys. GKMPAN has three attractive properties. First, it is significantly more efficient than group rekeying schemes that were adapted from those proposed for wired networks. Second, GKMPAN has the property of partial statelessness; that is, a node can decode the current group key even if it has missed a certain number of previous group rekeying operations. This makes it very attractive for ad hoc networks where nodes may lose packets due to transmission link errors or temporary network partitions. Third, in GKMPAN the key server does not need any information about the topology of the ad hoc network or the geographic location of the members of the group. We study the security and performance of GKMPAN through detailed analysis and simulation.

Composite key management for ad hoc networks

Abstract: We present composite key management, a novel paradigm for key management in ad hoc networks. While most existing approaches try to fit techniques developed for wired environments into ad hoc networks, our approach works within the specific limitations of ad hoc networks to increase security and availability of the key management framework. By composing techniques from PKI and certificate chaining, composite key management follows two fundamental principles that must be satisfied by an ad hoc key management framework: node participation and the use of a trusted third party. We introduce enhanced metrics of authentication to aid end users in understanding and using the key management framework. Through simulation studies, we demonstrate the effectiveness of composite key management under stressful scenarios where previous approaches fail and show that composite key management can address the challenges posed by the unique nature of ad hoc networks.

Cross-layer congestion control in ad hoc wireless networks

Abstract: The paper presents the problem of performance degradation of transport layer protocols due to congestion of wireless local area networks. Following the analysis of available solutions to this problem, a cross-layer congestion avoidance scheme (C 3 TCP) is presented, able to obtain higher performance by gathering capacity information such as bandwidth and delay at the link layer. The method requires the introduction of an additional module within the protocol stack of the mobile node, able to adjust the outgoing data stream based on capacity measurements. Moreover, a proposal to provide optional field support to existing IEEE 802.11 protocol, in order to support the presented congestion control solution as well as many other similar approaches, is presented. Achieved results underline good agreement with design considerations and high utilization of the available resources. � 2005 Elsevier B.V. All rights reserved.

The Bordercast Resolution Protocol (BRP) for Ad Hoc Networks

Abstract: A control mechanism is provided for a carburetor having an automatic choke which includes a cam carried on the valve shaft of the choke valve and a stopper member movable to be brought into engagement with the cam so as to restrict the opening of the choke valve at the time of engine starting. The restriction effected by engagement of the stopper with the cam is removed when the ambient temperature of the carburetor is sufficiently high or when the engine has reached a sufficiently warmed-up condition.