Showing papers on "Key distribution in wireless sensor networks published in 1994"

Adaptation and mobility in wireless information systems

Abstract: The author begins by discussing the background, defining key terms and showing how wireless information systems can be viewed as a natural evolution of computing's relentless march toward greater distribution and ubiquity of access. Next, the research issues faced by designers of wireless information systems are detailed, and some large-scale engineering challenges for such designers are presented. The existing cellular system architecture, evolved from telephony, is compared with an alternative architecture more closely integrated with a computer networking view of wireless systems. Existing wireless systems are reviewed, and the final section presents the author's summary and conclusions, and charts the future of wireless information systems. >

Privacy and authentication for wireless local area networks

Abstract: Wireless networks are being driven by the need for providing network access to mobile or nomadic computing devices. Although the need for wireless access to a network is evident, new problems are inherent in the wireless medium itself. Specifically, the wireless medium introduces new opportunities for eavesdropping on wireless data communications. Anyone with an appropriate wireless receiver can eavesdrop, and this kind of eavesdropping is virtually undetectable. Furthermore, since the wireless medium cannot be contained by the usual physical constraints of walls and doors, active intrusions through the wireless medium are also made easier. In order to prevent this unauthorized access to the network, the authors present the design of a secure communication protocol that provides for both the privacy of wireless data communications and the authenticity of communicating parties. The placement of the protocol in the overall protocol stack and issues relevant to wireless links and mobile computing devices are discussed. They also present proof of the security of the protocol using the logic of authentication formalism developed by Burrows, Abadi, and Needham (1990). >

Communication network providing wireless and hard-wired dynamic routing

Abstract: A data communication network for providing dynamic routing through both wireless and wired subnetworks to support wireless communication devices and wired remote stations is disclosed. In the wireless network, the wireless communication devices can be mobile RF terminals, while the wired remote stations might be personal computers attached to a wired subnet, such as an ethernet coaxial cable. The wireless network architecture utilizes a spanning tree configuration which provides for transparent bridging between wired subnets and the wireless subnets. The spanning tree configuration provides dynamic routing to and from wireless communication devices and remote stations attached to standard IEEE 802 LANs.

Method and apparatus for bridging wireless LAN to a wired LAN

Abstract: An internetworking node for providing internetworking services for mobile wireless nodes is disclosed. Each mobile wireless node is registered withat the most one internetworking node. Each mobile wireless node emits a topologybroadcast identifying itself and other nodes it has heard. Each internetworking node uses these topology broadcasts to construct a table tracking each mobile node within its range, whether that mobile node is registered to that internetworking node and also a list of which other nodes that mobile wireless node can hear. The internetworking node determines which of these wireless nodes it will register. The internetworking node will then act for all wireless nodes registered to it in relaying messages between wireless nodes or between a wired LAN and the wireless nodes.

Intelligent Sensor Systems

Abstract: Signals and systems physical principles of sensing electronic measurement techniques enabling technologies intelligent sensor concepts communication and sensor networks physical realizations.

Disconnection management system for wireless voice communications

Abstract: A communications system is designed to monitor voice communications signals for an initial end-to-end communications link which is comprised of a) a wireless segment which connects a wireless network to a wireless end-user apparatus, and b) a second segment which connects a communications end-user device to the wireless network. When the system detects that the wireless segment is inoperative, it inhibits the release of the second segment. Thereafter, the system sets up a subsequent wireless segment which extends from the wireless network to the wireless end-user apparatus. The subsequent wireless segment is then bridged to the second segment to form a new end-to-end communications link to restore connectivity between the wireless end-user apparatus and the communications end-user device.

Secure wireless LANs

Abstract: Mobile computing is a major area of current research. A variety of wirelessly networked mobile devices now make it possible for a physically untethered computer to function in a fully networked manner. Recent research has focussed on providing the mobile user a seamless environment of wired and wireless networks. One of the major hurdles in providing such a seamless environment is that wireless media are inherently less secure.In this paper, we propose a security scheme for wireless media which permits secure communication over a single wireless channel. Our scheme allows both communicating parties to authenticate each other and establish a shared key for secure communication. An unauthorized snooper cannot even discover the identity of the communicating parties. Mobile computers are thus provided a highly secure wireless environment. We describe an efficient practical implementation of the scheme and prove its correctness.

Approaches to layered coding for dual-rate wireless video transmission

Abstract: Visual communications over wireless networks require the efficient and robust coding of video signals for transmission over wireless links having time-varying channel capacity. The authors compare several schemes for encoding video data into two priority streams, thereby enabling the transmission of video data over wireless links to be switched between two bit rates. An H.261 (p/spl times/64) algorithm is modified to implement each candidate scheme. The algorithms are evaluated for a microcellular wireless environment and a clear-channel bit rate of 65 kb/s. The results show that by combining layering with automatic-repeat request (wireless-)link control, almost-wireline visual quality can be achieved. >

Advanced wireless access system

Abstract: This paper describes an advanced wireless system which is composed of a wireless access node, a wireless access point, and a multimedia portable terminal. The wireless access node and access point are connected by optical fibers to realize broadband and high quality transmission. The radio frequency spectrum is directly carried on optical fibers using "fiber radio" technologies. This advanced wireless system, the multimedia wireless access system, provides video and data communications as well as voice services.

Functional approach to a hybrid wireless network for mobile stations

Abstract: The limited range of wireless mediums is often compensated for by a cellular topology controlled by base stations interconnected by means of a wired infrastructure. The size of the area covered by such networks varies a lot according to the wireless medium used. They do, however, share certain functionalities which are presented here in the form of a functional model. To simulate this type of hybrid network, it is necessary to identify all parameters involved which may have an influence. This preoccupation led to an Entity model which is detailed in this paper for the case of an infrared wireless LAN for in-house communications. The principal parameters are classified and assigned to entities. The interactions between these entities and the characteristics of the network are identified for a future simulation.

Sensor management using the decentralized Kalman filter

Abstract: Previous work in data fusion has seen the development of a range of architectures for multi-sensor data fusion systems, from fully centralised through distributed to fully decentraiised [1, 2]. This paper presents some further experimental results obtained from an implementation of a multi-target tracking system built around a fully decentralised Kalman filter (DKF) [3, 4]. Here we concentrate on the problem of sensor management, and consider how the individual sensors in a decentraiised sensing network can use the information in the global picture to make decisions about which targets to observe. Explicit use is made of the information available locally to a sensor to control its pointing and target detection. The sensor modality (e.g. range only, bearing only, etc.) strongly affects the way in which the sensor is managed. The tracking system integrates an essentially range-only sensor with a bearing-only sensor [5]. The sensors run asynchronously from each other, and also exhibit asynchronous first detection. These effects are studied in the context of known target motion, as is the temporary removal of one of the sensors from the system. Of particular importance is the effect limited communications bandwidth has on the timeliness of the information exchange. Possible applications of the work are discussed, and suggestions are made for further research. This paper is organised as follows. First we review some background material, including the decentralised data fusion test bed used for the experiments reported here. Then we address the sensor management problem, and describe the experiments we have performed; these focus on assessing the impact on the performance of the data fusion system as a whole of employing sensor management. Finally, we draw some conclusions, and indicate some possible future work.

GRAPO-optimized group randomly addressed polling for wireless data network

Abstract: This paper presents a MAC (medium access control) layer protocol GRAPO (optimized group randomly addressed polling) for wireless (local area) data network GRAPO statically optimizes the original version of GRAP proposed by Kwang-Cheng Chen (1992) to deliver smooth convergence and better throughput/delay performance It is a good candidate of the MAC protocol for wireless LANs and other wireless network applications >