Benjamin William Allen

Novel UWB pulse shaping using prolate spheroidal wave functions

In this paper novel prolate spheroidal wave functions are proposed as pulse shapes for use in impulse radio (ultra-wideband) communications. These classes of functions yields orthogonal pulses and have a constant pulse width regardless of the pulse order. This is an important property since it eliminates inter-symbol interference. An M-ary communications system is considered that employs these pulses, and the generation of these pulses using the eigenfunction form of a self-adjoint operator is proposed. It is also shown that these pulses are suitable for use in pulse position modulation (PPM) ultra wideband (UWB) communication systems.

A novel single base station location technique for microcellular wireless networks: description and validation by a deterministic propagation model

Positioning algorithms in cellular networks has become increasingly important as a means of supporting emerging services that require a sufficiently precise estimation of the position of the mobile terminal (MT) associated with a given base station (BS). Currently, even the most sophisticated positioning algorithms require at least three BSs to achieve satisfactory precision. This paper presents a novel algorithm that makes use of a single-BS antenna array to locate MTs in cellular networks. A triangulation technique is utilized and supported by some minimal information about the environment in the BS neighborhood. This algorithm is shown to perform well when operating in a microcellular environment with perfect channel-parameter estimation. The effect of finite resolution of the input parameters is also investigated. The performance is analyzed for a universal mobile telecommunications system microcellular scenario through a three-dimensional deterministic channel model. Finally, the performance of the proposed positioning technique is compared to the well-known location method based on the time-of-arrival measurements at three different BSs.

Estimating position and velocity of mobile terminals in a microcellular network using an adaptive linear regression setup

Mobility tracking yields efficient network resource management and enables very useful additional services, provided that accurate online estimations of both the location and the velocity of a mobile user are performed. We present a novel method for tracing a mobile user by subsequently estimating his/her position through a single base station positioning (SBSP) method designed for microcellular and third generation (3G) wireless communications systems. Raw data about user position are then smoothed through a linear regression setup which adaptively varies its inertia on the basis of the previous observations. This results in a tracking method which is able to estimate both the location and the velocity of a user with high accuracy, as proven by numerical results obtained in different microcellular scenarios.

Performance evaluation of a Bluetooth interference canceller in IEEE802.11b wireless networks

In this paper, we propose a narrowband interference canceller (NIC) to cancel Bluetooth interference occurring in IEEE 802.11b WLAN systems. The proposed NIC has a simple structure: an adaptive filter followed by a Rake receiver. The simulation results show that the proposed NIC can effectively cancel Bluetooth interference in an 802.11b receiver. Although an IEEE802.11b/Bluetooth framework is given as an example, the proposed NIC can be used in any spread spectrum system with frequency-hopping narrowband interference (FHNBI).

A novel powerloss model for short range UWB transmissions

Narrowband pathloss models are not applicable to the link budget calculation of ultra wideband (UWB) systems. In this paper, a rigorous analysis reveals the powerloss behavior of short-range UWB systems when operating in a cluttered environment. The contribution of this paper is the derivation of a power law model that exhibits a novel breakpoint within the vicinity of the transmitter, which is shown to influence the UWB link budget by up to 5 dB.

Comparison of coherent and differential space-time block codes over spatially correlated channels

This paper compares the performance of coherent, differential and differential unitary space-time block codes operating over spatially correlated Rayleigh fading channels with up to four transmit antennas, ft is shown that, when operating over spatially correlated channels, the relative performance of all candidate codes is improved when the number of transmit antennas is kept low. Improved performance is also observed when differential STBC are used compared to coherent STBC.

Cost-Variant Sage: Field Trails and Results

By extending the Space-Alternating Generalised Expectation-Maximisation (SAGE) parameter estimation algorithm to include a novel cost variant process, the robustness of Direction of Arrival (DoA) estimation from the SAGE algorithm is shown here to improve. A novel extension to the standard SAGE algorithm that enhances the parameter estimation process is first introduced. Field trials that have been conducted using an adaptive antenna to verify the performance of this algorithm are presented. Results show the extended SAGE algorithm improves DoA performance compared to standard SAGE by 5deg when operating in an urban environment.

Report on the World Congress on Medical Physics and Biomedical Engineering--WC2003.

The general consensus of delegates was that WC2003, held in Sydney, Austra lia, 24-29 August 2003, was a great success. B oth t he scie ntific program and the congress environment were ve ry good, a nd were well regarded by our overseas visitors. Of the 2200 delegates, there were 1000 full, 200 day, 250 st udent, developing c ountries or retiree registrations , and 100 com plimentary registrations, am ounting to a

Adaptive array systems: fundamentals and applications

2,000,000 budget. There were 1000 oral and 1200 poster papers, from 74 di fferent countries, although unfortunately quite a few posters did not make it to the boards. New innovations were the poster kraals, a new Physics track for Ha dron Therapy, the Micro-Mini-dosimetry workshop and the Clinical Day. The Hadron Therapy track provided the first opportun ity for different heavy i on therapies such as boron ne utron ca pture the rapy (BNCT), targeted alpha the rapy (TAT), fast neutron therapy (FNT), proton therapy (PT), an d h eavy ion ther apy ( HIT) to be discussed. In view of the many overlapping aspects of these therapies, these joint sessi ons were considered to be an advance. The few poster kraals worked well, but the facilitator really needs t o know the topic very well. On the other hand, for the reason given above, the posters were not so successful. Other P hysics feat ures we re t he point-counterpoint sessions on chemotherapy dose, targeted screening, protons vs. i ntensity m odulated radiotherapy (IMR T), and radiotherapy modalities for glioblastoma. The inclusion of clinical specialists points to th e further i ntegration of different disciplines. The keynote speaker, L ord May of Oxford, suggested that the future of such Congresses lies in their broadening to be more inclusive than exclusive. The Congress was fina ncially successful. Income from registrations (

User positioning technique for microcellular wireless networks

1558K), sponsorships (