Wireless Personal Systems Research Articles

Miniature In-Phase Wilkinson Power Divider with Pair of Parallel Transmission-Lines for Application in Wireless Microwave Systems

A novel miniature Wilkinson power divider (WPD) design is presented. This is achieved by substituting the quarter-wavelength transmission-lines constituting the WPD with an equivalent pair of parallel transmission-lines (PPTLs) that effectively reduce the circuit size of the WPD by 43% compared with a conventional design whose ground-plane is defected. Particle swarm optimization (PSO) technique is used to achieve size reduction. Meandering the transmission-lines further reduce the WPD size by 22%. The proposed WPD has overall dimensions of 9.38 × 11.51 mm2 or 0.11 λg × 0.14 λg , which is compatible with the requirements imposed by portable personal wireless systems. Coupling between the parallel transmission-lines is shown to extend the operational bandwidth of the power divider to 3.2 GHz (0.8–4 GHz) for a return-loss better than 10 dB.

The use of the Cochlear Mini Microphone (MM) as a personal radio system (FM) with young children who are deaf

Objectives: This paper describes the background, organization and findings of a project undertaken in 2016-2017, to examine the benefits and challenges of the use of the Cochlear Mini Microphone (MM) by the families of pre-school children with cochlear implants on the Nottingham Auditory Implant Programme.Methods: The experiences and views of 25 families who used the equipment were obtained and analysed. The information informed subsequent advice, patient literature and professional training.Results: The MM was viewed to be of benefit by just under half of the families. The attitudes and technical competence of families and local professionals, alongside the age and lifestyle of the children, were identified as the key factors affecting the amount of use.Conclusion: The insights gained into the challenges and benefits of the MM for this population offered explanations for the limited take-up of the equipment and informed ways to encourage appropriate useDiscussion: Equipment issued to very young children works best alongside specific advice and training, targeted at both families and local professionals. Despite some technical limitations, the availability of a personal radio system was found to be of benefit by some families. It encouraged consideration by both families and professionals, of the potential benefits of early introduction of a personal radio system into pre-school group activities and educational settings.

Special Issue on “Recent Trends on Convergence Personal Wireless System”

Special Issue on “Recent Trends on Convergence Personal Wireless System”

Applications and Security of Next-Generation, User-Centric Wireless Systems

Pervasive wireless systems have significantly improved end-users’ quality of life. As manufacturing costs decrease, communications bandwidth increases, and contextual information is made more readily available, the role of next generation wireless systems in facilitating users’ daily activities will grow. Unique security and privacy issues exist in these wireless, context-aware, often decentralized systems. For example, the pervasive nature of such systems allows adversaries to launch stealthy attacks against them. In this review paper, we survey several emergent personal wireless systems and their applications. These systems include mobile social networks, active implantable medical devices, and consumer products. We explore each system’s usage of contextual information and provide insight into its security vulnerabilities. Where possible, we describe existing solutions for defendingagainst these vulnerabilities. Finally, we point out promising future research directions for improving these systems’ robustness and security

Rapid acquisition algorithms for synchronization of bursty transmissions in CDMA microcellular and personal wireless systems

Two rapid synchronization acquisition algorithms applicable to spread spectrum links of code division multiple access (CDMA) personal communication systems are proposed and evaluated. The algorithms operate within a self-referencing matched filter synchronizer structure, and are particularly useful in reducing synchronization overhead on links designed to carry packet-type services. The main distinguishing characteristic between the two schemes is that one uses hard-decision while the other uses soft-decision detection. The proposed schemes are especially applicable to reverse link transmissions in quasisynchronous CDMA systems in which timing at portable terminals is established via pilot and synchronization signals received on respective code-division channels from the home base. If discontinuous (bursty) transmission is used on reverse links, the acquisition process is required for each transmission burst because of the propagation time uncertainty. Analysis of the algorithms on additive white Gaussian noise (AWGN) and Rayleigh fading channels reveals that their performance depends significantly on the choice of synchronizer parameters and the average despread signal-to-interference ratio (SIR). When this choice is proper, acquisition over a single preamble of relatively short duration can be achieved with high probability. The soft-decision scheme introduces a performance advantage of between 4-9 dB depending on the length of the synchronizing preamble.

Millimeter wave personal radio using an advanced communication satellite

THIS PAPER describes a millimeter-wave personal radio system using a communications satellite. It focuses on the development of a 50/40-GHz-band earth station. First, the trends of future satellite services are discussed. Satellite communications will be ready for personal utilization, namely the personalization of satellite communications, in the near future. The idea of a personal radio using a satellite and an example of an advanced communications satellite are introduced. The communications system and access method are also discussed and an FDMA system is recommended. Second, a small earth station for the millimeter-wave personal radio is proposed which has a 30-cm-diameter antenna, a transmission rate of 64 kb/s for wide applications, direct FSK modulation in the RF stage, the local signal fed from the transmit system, and link availability of 99%.

Personal radio systems and applications

This paper is a discussion of the system aspects of radio systems designed to use the new types of Personal Radio Equipments which have been, and are being, introduced to the market in increasing numbers and types. Several actual applications are discussed. These examples cover the two basic types of equipment now in use, which are two-way non-selective call units, and one-way selective calling paging units. The basic capabilities of the personal equipment are examined insofar as they pertain to Personal Radio System Design. The limitation and advantage of this equipment as well as the new uses and applications of this equipment are treated.