P.M. Grant

Bio: P.M. Grant is an academic researcher from University of Strathclyde. The author has contributed to research in topics: Wheelchair & Population. The author has an hindex of 5, co-authored 8 publications receiving 686 citations.

Digital communications. 3rd ed

Abstract: Digital communications is the foundation of modern telecommunications and digital signal processing. The second edition of Digital Communications is updated to include current techniques and systems used in the rapidly expanding field of fixed and mobile communications. The text has comprehensive coverage of digital communications without going into unnecessary detail or irrelevant topics. Its main aims are to develop the mathematical theory behind signal processing and use this knowledge to develop fixed and mobile data communications systems. This text is geared towards students who already have a technical understanding of electrical engineering from their introductory years at university and who wish to focus on digital communications. It covers everything these students will need to know, including modern techniques.

Enhancement of a virtual reality wheelchair simulator to include qualitative and quantitative performance metrics

Abstract: The increasing importance of inclusive design and in particular accessibility guidelines established in the U.K. 1996 Disability Discrimination Act (DDA) has been a prime motivation for the work on wheelchair access, a subset of the DDA guidelines, described in this article. The development of these guidelines mirrors the long-standing provisions developed in the U.S. In order to raise awareness of these guidelines and in particular to give architects, building designers, and users a physical sensation of how a planned development could be experienced, a wheelchair virtual reality system was developed. This compares with conventional methods of measuring against drawings and comparing dimensions against building regulations, established in the U.K. under British standards. Features of this approach include the marriage of an electromechanical force-feedback system with high-quality immersive graphics as well as the potential ability to generate a physiological rating of buildings that do not yet ...

Development of a wheelchair virtual reality platform for use in evaluating wheelchair access

Abstract: In the UK the Disability Discrimination Act 1995 aims to end discrimination against disabled people. Importantly the Act gives the disabled community new employment and access rights. Central to these rights will be an obligation for employers and organisations to provide premises which do not disadvantage disabled people. Many disabled people rely on wheelchairs for mobility. However, many buildings do not provide conditions suited to wheelchair users. This project aims to provide instrumentation allowing wheelchair navigation within virtual buildings. The provision of such instrumentation assists architects in identifying the needs of wheelchair users at the design stage. Central to this project is the need to provide a platform which can accommodate a range of wheelchair types, that will map intended wheelchair motion into a virtual world and that has the capacity to provide feedback to the user reflecting changes in floor surface characteristics and slope. The project represents a collaborative effort between architects, bioengineers and user groups and will be comprised of stages related to platform design, construction, interfacing, testing and user evaluation.

Designing a visible city for visually impaired users

Abstract: This paper reports on an ongoing doctoral research project which aims to identify the main barriers to access within the built environment for persons with a visual impairment. The research seeks to investigate whether these barriers are common for all types of visual impairment and degree of vision loss and if so, what inclusive design solutions can accommodate the needs of the majority of visually impaired users. An access audit has been conducted within Glasgow city centre which sought to quantify the number and type of hazards present within a typical built environment. This was followed up by a questionnaire which asked participants to rate factors which may prevent them from making independent visits to their nearest city centre including psychological factors, physical features and obstructions resulting from the presence of street furniture. Participants also indicated the colours and contrasts which they find easiest to detect within the built environment. These findings will be used to inform the creation of a new set of design guidelines to assist designers, architects and urban planners as to how they can provide more accessible and inclusive environments for the visually impaired population.

Virtual environments for special needs - changing the VR paradigm

Abstract: The normal application of Virtual Reality is to the simulation of environments, which are in some way special - remote, hazardous or purely imaginary. This paper describes research and development work which changes the paradigm by simulating perfectly ordinary buildings for special people. Some 15% of the population have some form of physical impairment - a proportion which is likely to rise in line with an ageing population. New legislation, such as the UK Disability Discrimination Act places additional responsibility on building owners to ensure adequate access for people with an impairment and this in turn will place additional responsibility on the architect. Current methods of auditing access for new building are primitive and require the auditor to interpret plans/sections of the proposed building against a checklist of requirements specific to the special need. This paper reports on progress in the use of an immersive VR facility to simulate access to buildings for two broad classes of user: i) those with a mobility impairment; ii) those with visual impairment. In the former case, a wheelchair motion platform has been designed which allows the wheelchair user to navigate the virtual building; a brake and motor connected to the rollers on which the wheelchair sits facilitate the effects of slope and surface resistance. In the latter case, the main categories and degrees of visual impairment can be simulated allowing architects to assess the contribution of form, colour and signage to safe access

Capacity Limits of Optical Fiber Networks

Abstract: We describe a method to estimate the capacity limit of fiber-optic communication systems (or ?fiber channels?) based on information theory. This paper is divided into two parts. Part 1 reviews fundamental concepts of digital communications and information theory. We treat digitization and modulation followed by information theory for channels both without and with memory. We provide explicit relationships between the commonly used signal-to-noise ratio and the optical signal-to-noise ratio. We further evaluate the performance of modulation constellations such as quadrature-amplitude modulation, combinations of amplitude-shift keying and phase-shift keying, exotic constellations, and concentric rings for an additive white Gaussian noise channel using coherent detection. Part 2 is devoted specifically to the "fiber channel.'' We review the physical phenomena present in transmission over optical fiber networks, including sources of noise, the need for optical filtering in optically-routed networks, and, most critically, the presence of fiber Kerr nonlinearity. We describe various transmission scenarios and impairment mitigation techniques, and define a fiber channel deemed to be the most relevant for communication over optically-routed networks. We proceed to evaluate a capacity limit estimate for this fiber channel using ring constellations. Several scenarios are considered, including uniform and optimized ring constellations, different fiber dispersion maps, and varying transmission distances. We further present evidences that point to the physical origin of the fiber capacity limitations and provide a comparison of recent record experiments with our capacity limit estimation.

Wireless sub-THz communication system with high data rate

Abstract: A wireless communication system with a maximum data rate of 100 Gbit s−1 over 20 m is demonstrated using a carrier frequency of 237.5 GHz. The photonic schemes used to generate the signal carrier and local oscillator are described, as is the fast photodetector used as a mixer for data extraction.

Multichannel Blind Source Separation Using Convolution Kernel Compensation

Abstract: This paper studies a novel decomposition technique, suitable for blind separation of linear mixtures of signals comprising finite-length symbols. The observed symbols are first modeled as channel responses in a multiple-input-multiple-output (MIMO) model, while the channel inputs are conceptually considered sparse positive pulse trains carrying the information about the symbol arising times. Our decomposition approach compensates channel responses and aims at reconstructing the input pulse trains directly. The algorithm is derived first for the overdetermined noiseless MIMO case. A generalized scheme is then provided for the underdetermined mixtures in noisy environments. Although blind, the proposed technique approaches Bayesian optimal linear minimum mean square error estimator and is, hence, significantly noise resistant. The results of simulation tests prove it can be applied to considerably underdetermined convolutive mixtures and even to the mixtures of moderately correlated input pulse trains, with their cross-correlation up to 10% of its maximum possible value.

Wireless Myths, Realities, and Futures: From 3G/4G to Optical and Quantum Wireless

Abstract: 1) The Myth: Sixty years of research following Shannon's pioneering paper has led to telecommunications solutions operating arbitrarily close to the channel capacity-“flawless telepresence” with zero error is available to anyone, anywhere, anytime across the globe. 2)The Reality: Once we leave home or the office, even top of the range iPhones and tablet computers fail to maintain "flawless telepresence" quality. They also fail to approach the theoretical performance predictions. The 1000-fold throughput increase of the best third- generation (3G) phones over second-generation (2G) GSM phones and the 1000-fold increased teletraffic predictions of the next decade require substantial further bandwidth expansion toward ever increasing carrier frequencies, expanding beyond the radiofrequency (RF) band to optical frequencies, where substantial bandwidths are available. 3) The Future: However, optical and quantum-domain wireless communications is less developed than RF wireless. It is also widely recognized that the pathloss of RF wireless systems monotonically increases with the carrier frequency and this additional challenge has to be tackled by appropriate countermeasures in future research. Hence, we set out to seek promising techniques of tackling the aforementioned challenges and for resolving the conflicting design constraints imposed on the flawless telepresence systems of the future. To disspell the myth, we evaluate both the operational 3G as well as the emerging fourth-generation (4G) wireless systems and demonstrate that there is a substantial difference between their theoretical and their practically attainable performance. The reality is that the teletraffic predictions indicate further thirst for bandwidth, which cannot be readily satisfied within the most popular 1-2-GHz carrier-frequency range, where the best propagation conditions prevail. We briefly consider the 10-300-GHz unlicensed band as a potential source of further spectrum, followed by a review of advances way beyond the upper edge of the RF range at 300 GHz, namely to the realms of optical wireless (OW) communications. As the carrier frequency is increased, the pathloss is also increased, which results in ever smaller cells. Furthermore, the high-frequency RF waves predominantly obey line-of-sight (LOS) propagation-like visible light. The future requires advances in both infrared and visible-light communications for circumventing the LOS nature of light. We hypothesize that light-emitting diode (LED) arrays acting as "massive" multiple-input-multiple-output (MIMO) components as well as transmitter/receiver cooperation might be conceived. The heterogeneous networks of the near future will rely on seamless, near-instantaneous handovers among OW hotspots, RF hotspots, and oversailing larger cells. These "massive" MIMOs might impose a high complexity, hence their reduced-complexity noncoherently detected counterparts might be favored. Finally, we conclude by touching upon the promising research area of quantum-domain communications, which might be expected to circumvent the aforementioned complexity problem of massive MIMOs with the aid of efficient quantum-domain search techniques-a truly exciting research era

Flash memory apparatus and methods using a plurality of decoding stages including optional use of concatenated BCH codes and/or designation of “first below” cells

Abstract: A method for decoding a plurality of flash memory cells which are error-correction-coded as a unit, the method comprising providing a hard-decoding success indication indicating whether or not hard-decoding is at least likely to be successful; and soft-decoding the plurality of flash memory cells at a first resolution only if the hard-decoding success indication indicates that the hard-decoding is not at least likely to be successful.