58,730 research outputs found

    Quantitative Assessment of TV White Space in India

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    Licensed but unutilized television (TV) band spectrum is called as TV white space in the literature. Ultra high frequency (UHF) TV band spectrum has very good wireless radio propagation characteristics. The amount of TV white space in the UHF TV band in India is of interest. Comprehensive quantitative assessment and estimates for the TV white space in the 470-590MHz band for four zones of India (all except north) are presented in this work. This is the first effort in India to estimate TV white spaces in a comprehensive manner. The average available TV white space per unit area in these four zones is calculated using two methods: (i) the primary (licensed) user and secondary (unlicensed) user point of view; and, (ii) the regulations of Federal Communications Commission in the United States. By both methods, the average available TV white space in the UHF TV band is shown to be more than 100MHz! A TV transmitter frequency-reassignment algorithm is also described. Based on spatial-reuse ideas, a TV channel allocation scheme is presented which results in insignicant interference to the TV receivers while using the least number of TV channels for transmission across the four zones. Based on this reassignment, it is found that four TV band channels (or 32MHz) are sufficient to provide the existing UHF TV band coverage in India

    Feasibility, Architecture and Cost Considerations of Using TVWS for Rural Internet Access in 5G

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    The cellular technology is mostly an urban technology that has been unable to serve rural areas well. This is because the traditional cellular models are not economical for areas with low user density and lesser revenues. In 5G cellular networks, the coverage dilemma is likely to remain the same, thus widening the rural-urban digital divide further. It is about time to identify the root cause that has hindered the rural technology growth and analyse the possible options in 5G architecture to address this issue. We advocate that it can only be accomplished in two phases by sequentially addressing economic viability followed by performance progression. We deliberate how various works in literature focus on the later stage of this ‘two-phase’ problem and are not feasible to implement in the first place. We propose the concept of TV band white space (TVWS) dovetailed with 5G infrastructure for rural coverage and show that it can yield cost-effectiveness from a service provider’s perspective

    Some initial results and observations from a series of trials within the Ofcom TV White Spaces pilot

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    Changing lifestyles and consumption patterns in developing countries: A scenario analysis for China and India

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    China and India are the world's largest developing economies and also two of the most populous countries. China, which now has more than 1.3 billion people, is expected to grow to more than 1.4 billion by 2050, and India with a population of 1 billion will overtake China to be the most populous country with about 1.6 billion population. These two countries are home to 37% of the world's population today. In addition, China and India have achieved notable success in their economic development characterised by a high rate of gross domestic product (GDP) growth in the last two decades. Together the two countries account already for almost a fifth of world GDP. The most direct and significant result of economic growth in India and China is the amazing improvement in quality of life (or at least spending power) for an increasing share of the population. The populations of both the countries have experienced a transition from ‘poverty’ to ‘adequate food and clothing’; today growing parts of the population are getting closer to ‘well to do lifestyles’. These segments of the society are not satisfied any more with enough food and clothes, but are also eager to obtain a quality life of high nutrient food, comfortable living, health care and other quality services. The theme of this paper is to analyse how the major drivers contributed to the environmental consequences in the past, and to take a forward look at the environmental impacts of these driving forces in China and India. The paper identifies population, affluence and technology to be the major driving forces in environmental pollution for these two countries then applies the simple equation of Impact=Population×Affluence×Technology, or I=PAT to evaluate the effects of changes in these drivers on CO2 emissions

    Systematic literature review of determinants of sedentary behaviour in older adults:a DEDIPAC study

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    BACKGROUND: Older adults are the most sedentary segment of society and high sedentary time is associated with poor health and wellbeing outcomes in this population. Identifying determinants of sedentary behaviour is a necessary step to develop interventions to reduce sedentary time. METHODS: A systematic literature review was conducted to identify factors associated with sedentary behaviour in older adults. Pubmed, Embase, CINAHL, PsycINFO and Web of Science were searched for articles published between 2000 and May 2014. The search strategy was based on four key elements: (a) sedentary behaviour and its synonyms; (b) determinants and its synonyms (e.g. correlates, factors); (c) types of sedentary behaviour (e.g. TV viewing, sitting, gaming) and (d) types of determinants (e.g. environmental, behavioural). Articles were included in the review if specific information about sedentary behaviour in older adults was reported. Studies on samples identified by disease were excluded. Study quality was rated by means of QUALSYST. The full review protocol is available from PROSPERO (PROSPERO 2014: CRD42014009823). The analysis was guided by the socio-ecological model framework. RESULTS: Twenty-two original studies were identified out of 4472 returned by the systematic search. These included 19 cross-sectional, 2 longitudinal and 1 qualitative studies, all published after 2011. Half of the studies were European. The study quality was generally high with a median of 82 % (IQR 69-96 %) using Qualsyst tool. Personal factors were the most frequently investigated with consistent positive association for age, negative for retirement, obesity and health status. Only four studies considered environmental determinants suggesting possible association with mode of transport, type of housing, cultural opportunities and neighbourhood safety and availability of places to rest. Only two studies investigated mediating factors. Very limited information was available on contexts and sub-domains of sedentary behaviours. CONCLUSION: Few studies have investigated determinants of sedentary behaviour in older adults and these have to date mostly focussed on personal factors, and qualitative studies were mostly lacking. More longitudinal studies are needed as well as inclusion of a broader range of personal and contextual potential determinants towards a systems-based approach, and future studies should be more informed by qualitative work

    Avatars Going Mainstream: Typology of Tropes in Avatar-Based Storytelling Practices

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    Due to the growing popularity of video games, gaming itself has become a shared experience among media audiences worldwide. The phenomenon of avatar-based games has led to the emergence of new storytelling practices. The paper proposes a typology of tropes in these avatar-based narratives focusing on non-game case studies. Suggested tropes are also confronted with the latest research on avatars in the area of game studies and current knowledge of the issues concerning the player-avatar relationship. Some of the most popular misconceptions regarding the gameplay experience and its representation in non-game media are exposed as a result of this analysis. The research confirms that popular culture perceives gaming experience as closely related to the player identity, as the latter inspires new genres of non-game narratives

    Performance analysis of a novel decentralised MAC protocol for cognitive radio networks

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    Due to the demand of emerging Cognitive Radio (CR) technology to permits using the unused licensed spectrum parts by cognitive users (CUs) to provide opportunistic and efficient utilisation of the white spaces. This requires deploying a CR MAC with the required characteristics to coordinate the spectrum access among CUs. Therefore, this paper presents the design and implementation of a novel Medium Access Control (MAC) protocol for decentralised CRNs (MCRN). The protocol provides efficient utilisations of the unused licensed channels and enables CUs to exchange data successfully over licensed channels. This is based on the observation procedure of sensing the status of the Licensed Users (LUs) are ON or OFF over the licensed channels. The protocol is validated with the comparison procedure against two different benchmark protocols in terms of the network performance; communication time and throughput. Therefore, performance analysis demonstrated that the proposed MCRN perform better and achieve higher throughput and time benefits than the benchmarks protocols

    Design and Experimental Evaluation of a Database-Assisted V2V Communications System Over TV White Space

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    Automakers are increasingly employing wireless communications technologies into vehicles, which are expected to be one of the primary tools to improve traffic flow and traffic safety. Anticipating a significant increase in the accompanying spectrum and capacity requirements, in this paper, we speculate about using dynamic spectrum access in general, and TV white space in particular for vehicular communications. To this end, we describe the concept, design, general architecture and operation principles of a vehicle-to-vehicle communications system over TV white space. This system makes dual use of a geolocation database and spectrum sensing to understand spectrum vacancies. In this architecture, whenever a database query result is available, that information is prioritized over sensing results and when the database access is disrupted, vehicles rely on the spectrum sensing results. After describing the general concepts, we numerically analyze and evaluate the benefits of using proxy vehicles for geolocation database access. Finally, we present the middleware-centric implementation and field test results of a multi-hop vehicle-to-vehicle communications system over the licensed TV-band. We present results regarding multi-hop throughput, delay, jitter, channel switching and database access latencies. This study complements our previous work which described spectrum sensing based vehicle-to-vehicle communications design and testing
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