Chatschik Bisdikian

An overview of the Bluetooth wireless technology

The Bluetooth/sup TM/ wireless technology is designed as a short-range connectivity solution for personal, portable, and handheld electronic devices. Since May 1998 the Bluetooth SIG has steered the development of the technology through the development of an open industry specification, including both protocols and application scenarios, and a qualification program designed to assure end-user value for Bluetooth products. This article highlights the Bluetooth wireless technology.

PARO: supporting dynamic power controlled routing in wireless ad hoc networks

This paper introduces PARO, a dynamic power controlled routing scheme that helps to minimize the transmission power needed to forward packets between wireless devices in ad hoc networks. Using PARO, one or more intermediate nodes called “redirectors” elects to forward packets on behalf of source–destination pairs thus reducing the aggregate transmission power consumed by wireless devices. PARO is applicable to a number of networking environments including wireless sensor networks, home networks and mobile ad hoc networks. In this paper, we present the detailed design of PARO and evaluate the protocol using simulation and experimentation. We show through simulation that PARO is capable of outperforming traditional broadcast-based routing protocols (e.g., MANET routing protocols) due to its energy conserving point-to-point on-demand design. We discuss our experiences from an implementation of the protocol in an experimental wireless testbed using off-the-shelf radio technology. We also evaluate the impact of dynamic power controlled routing on traditional network performance metrics such as end-to-end delay and throughput.

Fast track article: Looking ahead in pervasive computing: Challenges and opportunities in the era of cyber-physical convergence

The physical environment is becoming more and more saturated with computing and communication entities that interact among themselves, as well as with users: virtually everything will be enabled to source information and respond to appropriate stimuli. In this technology-rich scenario, real-world components interact with cyberspace via sensing, computing and communication elements, thus driving towards what is called the Cyber-Physical World (CPW) convergence. Information flows from the physical to the cyber world, and vice-versa, adapting the converged world to human behavior and social dynamics. Indeed humans are at the center of this converged world since information about the context in which they operate is the key element to adapt the CPW applications and services. Alongside, a new wave of (human) social networks and structures are emerging as important drivers for the development of novel communication and computing paradigms. In this article we present some of the research issues, challenges and opportunities in the convergence between the cyber and physical worlds. This article is not a comprehensive survey of all aspects of the CPW convergence. Instead, it presents some exciting research challenges and opportunities identified by members of the journals editorial board with a goal to stimulate new research activities in the emerging areas of CPW convergence.

Autonomic personal computing

Autonomic personal computing is personal computing on autonomic computing platforms. Its goals combine those of personal computing with those of autonomic computing. The challenge of personal autonomic computing is to simplify and enhance the end-user experience, delighting the user by anticipating his or her needs in the face of a complex, dynamic, and uncertain environment. In this paper we identify the key technologies that enable autonomic behavior as distinguished from fault-tolerant behavior. We give some examples of current autonomic behavior and some general considerations for an architecture that supports autonomic personal computing. We identify its challenges to standards and technology developers and conclude with some guidance for future work.

QoS provisioning in wireless/mobile multimedia networks using an adaptive framework

Recently there is a growing interest in the adaptive multimedia networking where the bandwidth of an ongoing multimedia call can be dynamically adjusted. In the wireless/mobile multimedia networks using the adaptive framework, the existing QoS provisioning focused on the call blocking probability and the forced termination probability should be modified. We, therefore, redefine a QoS parameter – the cell overload probability – from the viewpoint of the adaptive multimedia networking. Then, we propose a distributed call admission control (CAC) algorithm that guarantees the upper bound of the cell overload probability. Also, a bandwidth adaptation algorithm which seeks to minimize the cell overload probability is also presented. Simulation experiments are carried out to verify the performance of the proposed CAC algorithm. Furthermore, the performance of the adaptive wireless/mobile network is compared to that of the existing non-adaptive wireless/mobile networks. As a further step in QoS provisioning, we propose another QoS parameter, the degradation period ratio, and discuss analytically how the CAC algorithm guarantees the upper bound of the degradation period ratio.

Waiting time analysis in a single buffer DQDB (802.6) network

The statistics of the request and countdown counters of a user in a network that operates with the DQDB (distributed queue dual bus) media access protocol are investigated. Assuming that a user can have at most one packet waiting for transmission, an expression is obtained for the steady-state generating function of the number of requests queued ahead of an arriving packet. Given this number, the waiting time of the packet can be easily obtained. The results provide an insight on how traffic, generated from the left and the right of a user in the network, affects the waiting time characteristics of packets generated by the user. >

A journey through the DQDB network literature

Abstract The Distributed Queue Dual Bus (DQDB) network has been adopted as the subnetwork for the IEEE 802.6 metropolitan area network (MAN) standard. Since its original proposition a few years back, DQDB has attracted significant attention because of the simplicity of its medium access control (MAC) protocol. The intense scrutiny that DQDB has been subjected to has lead to the identification of a number of its potential problems, and a number of “add-on” strategies have been proposed to “fix” such problems. Moreover, a number of architectural variations have also been proposed to improve the network behavior. Since there has been a literature explosion on DQDB over the past few years, this article is intended to extract the significant features of various DQDB-based investigations, and to present them in an unified manner.

MLAP: a MAC level access protocol for the HFC 802.14 network

Interactive residential broadband/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in todays cable TV (CATV) hybrid fiber/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial plants to HFC are quickly moving in this direction. MLAP is a flexible ATM-friendly MAC protocol that is capable of supporting various types of traffic with diverse quality-of-service requirements. We introduce a very versatile MAC protocol for the HFC 802.14 network. MLAP can provide integrated broadband services to the home, internetwork easily with ATM wide area networks, support QoS constraints for various types of traffic, and operate over a variety of physical layer protocols. Our presentation is only an extended summary of our medium-sharing protocol proposal to the IEEE 802.14 WG. We consider only error-free system operation. MLAP provides for the use of timers for the recovery of error situations in the network. MLAP is also supported by a management suite of protocols for management of the overall system.

On Sensor Sampling and Quality of Information: A Starting Point

Many sensor-based applications (re)act following the detection of certain events of interest. Hence, the effectiveness of these applications depends on the quality of the information (QoI) provided by their sensor-based event detectors. In this paper, we derive relationships between the QoI attributes of timeliness and confidence and the operational characteristics of sensor systems and the events they detect. By building upon the Neyman-Pearson hypothesis testing procedure, we study the dependence of these characteristics and attributes on each other and establish their theoretical performance boundaries

WiSAP: a wireless personal access network for handheld computing devices

New short-range wireless communication technologies would enable environment-aware, mobile, personal area networks. These new technologies will serve as enablers for ubiquitous, low-cost, low-complexity, small-sized information appliances. These appliances will serve as interaction tools between humans and computer-driven services and applications existing in either the close or distant vicinity of humans. The new application paradigms these new technologies will enable are explored. Furthermore, an experimental wireless personal access networking platform called WiSAP, developed to research these new technologies and applications paradigms, is presented. Finally, some of the experiences gained from WiSAP while designing a consumer-oriented portable wireless communication system suitable for wireless mobile personal access networks are also presented.