141 research outputs found

    Efficient TV white space filter bank transceiver

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    Future devices operating in the TV white space (TVWS) spectrum will require to access different bands at different locations and times in order to avoid interference to incumbent users, requiring agility and sufficient spectral masks to satisfy regulators. Further, with very high-speed ADCs and DACs becoming reality, the purpose of this paper is to present a transceiver front-end capable of simultaneously up- and downconverting a significant portion of the UHF band. The proposed approach takes a two-stage filter-bank conversion for implementation on state-of-the-art FPGAs. We present three different parameterisations, which are compatible with the 40 TVWS channels between 470 and 790MHz in Europe, and compare them in terms of complexity and latency

    Design considerations for a filter bank based TVWS transceiver

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    This paper discusses the design of a filter bank based transceiver capable of simultaneously up- or downconverting the entire TV white space (TVWS) frequency band. The spectral mask requirements favour a filter bank based approach, whereby RF sampling and the use of an FPGA for digital up- and down-conversion dictates a two-stage approach. Some of the design considerations, including filter design approaches, are discussed in this contribution

    TVWS filter bank transceiver on OMAP-L137 evaluation module

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    Communications devices operating in the TV white space (TVWS) spectrum will be strictly regulated, requiring compliance with spectral masks to protect incumbent users and sufficient frequency agility to allow access to numerous frequency bands at different times and locations. Therefore, future designs operating at radio frequency (RF) have been proposed. The purpose of this paper is to demonstrate an implementation of such a transceivers at a scale-down frequency implemented on the OMAP--L137 evaluation module, whereby the RF link can be replaced by the device's audio I/O, thus enabling easier observation and algorithm testing for students

    Digital RF multiplexing for a TVWS transceiver implementation

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    Future devices operating in the TV white space (TVWS) spectrum will require to access different bands at different locations and times in order to avoid interference to incumbent users, requiring agility and sufficient spectral masks to satisfy regulators. In order to realise radio devices capable of this, we briefly review design efforts on a radio transceiver capable up- and downconverting the 40 8MHz TVWS channels residing between 470MHz and 790MHz. While we briefly address the overall proposed structure, the aim of this contribution is to address the practical issues of interfacing data conversion devices sampling at RF to state-of-the-art FPGAs which can then perform the digital operations required for up- and downconversion

    Partially reconfigurable TVWS transceiver for use in UK and US markets

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    With more and more countries opening up sections of unlicensed spectrum for use by TV White Space (TVWS) devices, the prospect of building a device capable of operating in more than one world region is appealing. The difficulty is that the locations of TVWS bands within the radio spectrum are not globally harmonised. With this problem in mind, the purpose of this paper is to present a TVWS transceiver design which is capable of being reconfigured to operate in both the UK and US spectrum. We present three different configurations: one covering the UK TVWS spectrum and the remaining two covering the various locations of the US TVWS bands

    Travelling for Umrah:destination attributes, destination image, and post-travel intentions

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    This paper examines the links between cosmopolitanism, self-identity, and a desire for social interaction perceived destination image and behavioural intentions. A model tested using a sample of 538 Iranian visitors to Mecca for the purpose of Umrah. The result from the structural model suggests that destination attributes influence perceived destination image. Further, such tourists are likely to revisit or recommend Islamic destinations if their experience matches their perceived image of the destination. This implies that, while the religious characteristics of the destination remain important, destination managers cannot disregard the tangential, non-religious attributes of a destination which are crucial in order to satisfy more conventional tourist desires. As such, this study suggests that those managing religious travel destinations should endeavour to foster a welcoming image, where experience, interaction and tolerance are at the forefront of the destination’s offering

    Predicting reliability through structured expert elicitation with the repliCATS (Collaborative Assessments for Trustworthy Science) process

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    As replications of individual studies are resource intensive, techniques for predicting the replicability are required. We introduce the repliCATS (Collaborative Assessments for Trustworthy Science) process, a new method for eliciting expert predictions about the replicability of research. This process is a structured expert elicitation approach based on a modified Delphi technique applied to the evaluation of research claims in social and behavioural sciences. The utility of processes to predict replicability is their capacity to test scientific claims without the costs of full replication. Experimental data supports the validity of this process, with a validation study producing a classification accuracy of 84% and an Area Under the Curve of 0.94, meeting or exceeding the accuracy of other techniques used to predict replicability. The repliCATS process provides other benefits. It is highly scalable, able to be deployed for both rapid assessment of small numbers of claims, and assessment of high volumes of claims over an extended period through an online elicitation platform, having been used to assess 3000 research claims over an 18 month period. It is available to be implemented in a range of ways and we describe one such implementation. An important advantage of the repliCATS process is that it collects qualitative data that has the potential to provide insight in understanding the limits of generalizability of scientific claims. The primary limitation of the repliCATS process is its reliance on human-derived predictions with consequent costs in terms of participant fatigue although careful design can minimise these costs. The repliCATS process has potential applications in alternative peer review and in the allocation of effort for replication studies
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