Current Wireless Communication Research Articles

Mobility management for m-commerce requests in wireless cellular networks

Increasing number of sophisticated services provided by the current wireless communication systems have caused a significant transition from E-commerce to M-commerce. Enterprises have provided considerable new opportunities to promote their businesses accessible from small mobile devices such as personal digital assistant (PDA) or mobiles phones. These facilities are envisioned as the most convenient way of using M-commerce. Using such services from mobile phones or PDAs equipped with GSM/GPRS involve effective mobility management mechanisms in cellular networks--a popular architecture for wireless networks. Success of such systems will largely depend on the reliable connection for the roaming users. Consequently, Quality of Service (QoS) provision is one of the most challenging issues in the heterogeneous wireless network-based m-commerce systems. Such m-commerce systems enable users to roam between different wireless networks operators and geographical areas while providing interactive broadband services and seamless connectivity. This paper presents an analytical framework to model scarce channels in any cell for maximizing channel utilization and efficient handling of handover requests. Typical numerical experiments are presented to validate the analytical solution against simulation to study the effect of bursty traffic upon the performance of the cell in any cellular networks.

Architectural Features and Urban Propagation

Radiocoverage measurements in urban environments often unveil unexpected power distribution patterns. Architectural features seem to be the cause of this behavior, as demonstrated in this paper. We demonstrate that the elements of a typical building facade, such as windows, exterior doors, balconies and railings, should be considered as significant "sources" of EM radiation in several current wireless communication systems. We propose a method for modeling the influence of those scatterers in EM wave propagation. In our model, the major structural elements are represented by two sets of orthogonally arranged wedges. The uniform geometrical theory of diffraction is employed to calculate the scattering field. The simulation results show that such "urban" scatterers may create a dominant propagation mode in an urban canyon. Our predictions are additionally verified by experimental measurements, performed at two different sites. Finally, the influence of roadside foliage is investigated and conclusions are drawn on the resultant field

Mobile Police Information System Based on Web Services

The demand for communications anywhere, anytime, and on any device without recording the date is growing with the development of modern information technologies. Current wireless communications enable people to freely exchange information, while web services provide loosely-coupled, language-neutral, and platform-independent ways of linking applications within organizations, across enterprises, and across the Internet. This paper describes a mobile information system for police service, which integrates wireless communication technologies and web service technologies. The system satisfies the special demands of police information systems, such as security and interoperability. Policemen in the system can use various kinds of mobile terminals, such as mobile phones, tablet PCs, personal digital assistants, and laptops equipped with wireless LAN or GPRS to access data in the central database. The system is based on web services with a secure web service architecture and simple object access protocol message passing.

Design considerations of satellite-based vehicular broadband networks

Convergence between wireless networks is the main trend in current and future wireless communications. The distinct advantage of satellite and terrestrial network integration is the possibility to provide ubiquitous multimedia services in vehicles at any location. The key design considerations of mobile broadband satellite access technologies are given in this article. After presenting the conceptual models of a system and services, the design issues of satellite network synchronization and burst demodulation are described. The design considerations of medium access control, resource management, capacity, and buffer controls for internetworking are given. Also, the active antenna issues are provided along with a sample design.

Dedicated Short-Range Wireless Communications for Intelligent Transportation System Applications

In efforts to reduce traffic accidents and improve the efficient utilization of existing transportation networks, increasing attention is being given to the use of wireless communications between vehicles and roadside equipment to develop new intelligent transportation system (ITS) applications that can help improve the safety of transportation networks and reduce urban congestion. Of particular interest for the development of such applications are the currently proposed dedicated short-range communication (DSRC) wireless standards. This paper aims to provide transportation researchers and engineers with an introduction to these standards. The paper presents the current mobile wireless communication applications and standards, the various DSRC standards that have been proposed, their potential use in ITS applications, their envisioned implementation benefits, and the remaining research needs.

Dedicated Short-Range Wireless Communications for Intelligent Transportation System Applications: State of the Art

In efforts to reduce traffic accidents and improve the efficient utilization of existing transportation networks, increasing attention is being given to the use of wireless communications between vehicles and roadside equipment to develop new intelligent transportation system (ITS) applications that can help improve the safety of transportation networks and reduce urban congestion. Of particular interest for the development of such applications are the currently proposed dedicated short-range communication (DSRC) wireless standards. This paper aims to provide transportation researchers and engineers with an introduction to these standards. The paper presents the current mobile wireless communication applications and standards, the various DSRC standards that have been proposed, their potential use in ITS applications, their envisioned implementation benefits, and the remaining research needs.

Enabling Gigabit Network Access to End Users

To achieve innovative network architectures capable of delivering high-speed data transfers to end users, considerable efforts have been invested in minimizing or eliminating the bottlenecks that exist in high-speed network environments. These bottlenecks exist primarily at two levels, namely, network data transmission to the end system and data delivery within the end system to the user. For wired networks, improvements in fiber optic technologies have shifted the bottleneck from the underlying physical network to the end system. However, wireless networks still face obstacles at both levels to achieving high, end-to-end performance data delivery, particularly at gigabit per second rates. We first present current wireless communication technologies aimed at delivering gigabit per second transmission rates to end systems. We then investigate the bottleneck at the end system by exploring experimentally the performance benefits of a network interface architecture designed to enable high-performance, low-latency applications using minimal host resources. We compare the performance of our network interface architecture with the traditional one, using commodity PCs connected by gigabit per second local area networks running protocols such as TCP/IP and UDP/IP. We argue that such a network interface architecture can eliminate the bottlenecks prevalent in current end systems and, consequently, enables users to reap the full benefits of the high-speed networks available today.

Análisis de los Esquemas de Acceso Inalámbricos Propuestos para la Tercera Generación de Sistemas Celulares

The current wireless communications have a bottle neck because their low speed (9600 bps); this prevents that new services shall be implemented linked over Internet and the transmission of data and images or he/she makes that they appear with limitations, like it happens with the services WAP (WIRELESS APPLICATION PROTOCOL). The net of current telecommunications evolves toward the attainment of an unified net (wire net and wireless net); the evolution of the net contemplates the evolution of the elements that you/they configure it; consequently, the access part will have to evolve to make possible more and better communications among ends, without preventing that the other ones make the own thing. The outlines of wireless access of wide band proposed for cellular communications of third generation look for to respond to the challenge. Of them, W-CDMA and CDMA2000 are imposed as the technologies of access of more efficiency.

Robust image communication over wireless channels

Typical image compression algorithms produce data streams which require a very reliable communication-they are not designed for transmission in an environment in which data may be lost or delayed, as provided by current and next-generation wireless communication networks. Compression and transmission provisions that avoid catastrophic failure caused by lost, delayed, or errant packets are therefore imperative in order to provide reliable visual communication over such systems. This robustness is obtained by modifying the source coding and/or adding channel coding. This article presents an overview of both lossy and lossless source coding techniques and combined source/channel techniques providing robustness, presenting examples of successful techniques.

Wireless communication and computing at the construction jobsite

For many years, the walkie-talkie has been synonymous with the construction industry. During jobsite project execution, there are three variables which can either hinder or facilitate successful results, namely, quality, quantity, and timing of information. Wireless data communications technology is capable of delivering just-in-time information within the `last mile' between the trailer and a desired location on the jobsite. This paper reports on a study which surveyed information needs at the jobsite, emerging wireless data communications technology, and assessed the extent to which wireless data technology can fulfill the information needs of the jobsite [J.M. de la Garza, I. Howitt, Wireless communication and computing at the jobsite, Research Report 136-11, Construction Industry Institute, Austin, TX, 1997]. We have organized jobsite information needs into the following ten categories: (a) requests for information, (b) materials management, (c) equipment management, (d) cost management, (e) schedule and means and methods, (f) jobsite record keeping, (g) submittals, (h) safety, (i) QC/QA, and (k) future trends. Each category was analyzed in terms of its appropriateness to take advantage of wireless technology. The four formats considered to transmit information wirelessly were: (a) live voice, (b) live video, (c) batched data, and (d) live data. Current wireless communication technology has been classified into the following five classes: (a) circuit-switched wireless data systems, (b) packet-switched wireless data systems—this class was further subdivided into specialized mobile radio systems and cellular digital packet data systems, (c) wireless local area networks, (d) paging systems, and (e) satellite-based data communications. A primer for wireless communications covering both fundamental and advanced communications concepts has also been included to enable a better understanding of the issues involved in making trade-offs while configuring a wireless jobsite communication system. The example presented in this paper shows how a contractor can define a subset of information needs by choosing from those already articulated herein and determine if a given wireless technology should even be considered as a viable way of meeting the information needs that such company has.