2,377 research outputs found

    THz band multipath measurements and analysis

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    Abstract. The THz band is now becoming the core interest for many researchers as it offers massive bandwidth and high transmission rates. It is expected to be a solution to ongoing spectrum scarcity in the wireless communication world. Wave propagating through a channel is affected by various phenomena, especially in the case of non-line-of-sight (NLOS) condition. In this thesis work, measurement results on several NLOS propagation mechanisms such as reflection, diffraction, and penetration have been reported in the terahertz band ranging from 0.1 THz to 3 THz. Here, the primary focus is to measure the possible NLOS multipath, such as reflected, diffracted, and penetrated paths or a combination of multiple NLOS components. The goal is to evaluate and analyze the feasibility of those multipath in order to estimate the possibility to establish a communication link via such paths. The measurements have been conducted by using TeraView TeraPulse 4000, a measurement device that is based on THz time-domain spectroscopy (THz-TDS). Measurements were made under various NLOS propagation scenarios with several common indoor materials. Characteristics of the measured materials have also been reported. The results have been given as a function of frequency and measurement angles. Corresponding background theories and comparisons with the measurement results have also been investigated with subsequent analysis to check the relevance of the measurement results. The idea was to find possible multipath signals after various NLOS events while traveling through a channel and behavioural changes of the transmitted signal with the change of measurement scenarios. The measurement results agreed with the corresponding theories as expected. The THz band offers overall a decent NLOS wireless communication link between the receiver and transmitter at the lower angles

    Hand palm local channel characterization for millimeter-wave body-centric applications

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    The body-centric wireless channel characterization mostly utilizes whole body models. However, localized channels for body parts consistently interacting with the wireless device have their own importance. This paper attempts to characterize the hand palm local channel through experimental measurements at three millimeter-wave frequency bands of 27-28 GHz, 29-30 GHz, and 31-32 GHz. Five human subjects are used in this study. Net body loss is found to be 3dB for different subjects with subject-specific and varying palm shape size is found to be the primary affecting source. The repeatability of the on-body propagation measurements is found to be within 10% of variance

    Indoor wireless communications and applications

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    Chapter 3 addresses challenges in radio link and system design in indoor scenarios. Given the fact that most human activities take place in indoor environments, the need for supporting ubiquitous indoor data connectivity and location/tracking service becomes even more important than in the previous decades. Specific technical challenges addressed in this section are(i), modelling complex indoor radio channels for effective antenna deployment, (ii), potential of millimeter-wave (mm-wave) radios for supporting higher data rates, and (iii), feasible indoor localisation and tracking techniques, which are summarised in three dedicated sections of this chapter

    Cooperative Radio Communications for Green Smart Environments

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    The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin
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