From Multi-Keyholes to Measure of Correlation and Power Imbalance in MIMO Channels: Outage Capacity Analysis

An information-theoretic analysis of a multi-keyhole channel, which includes a number of statistically independent keyholes with possibly different correlation matrices, is given. When the number of keyholes or/and the number of Tx/Rx antennas is large, there is an equivalent Rayleigh-fading channel such that the outage capacities of both channels are asymptotically equal. In the case of a large number of antennas and for a broad class of fading distributions, the instantaneous capacity is shown to be asymptotically Gaussian in distribution, and compact, closed-form expressions for the mean and variance are given. Motivated by the asymptotic analysis, a simple, full-ordering scalar measure of spatial correlation and power imbalance in MIMO channels is introduced, which quantifies the negative impact of these two factors on the outage capacity in a simple and well-tractable way. It does not require the eigenvalue decomposition, and has the full-ordering property. The size-asymptotic results are used to prove Telatar's conjecture for semi-correlated multi-keyhole and Rayleigh channels. Since the keyhole channel model approximates well the relay channel in the amplify-and-forward mode in certain scenarios, these results also apply to the latterComment: accepted by IEEE IT Trans., 201

Planning and realization of a WiFi 6 network to replace wired connections in an enterprise environment

WiFi (Wireless Fidelity) is a popular wireless LAN technology. It provides broadband wireless connectivity to all the users in the unlicensed 2.4 GHz and 5 GHz frequency bands. Given the fact that the WiFi technology is much easier and cost-efficient to deploy, it is rapidly gaining acceptance as an alternative to a wired local area network. Nowadays the Wireless access to data is a necessity for everyone in the daily life. Considering the last 30 years, the unlimited access to information has transformed entire industries, fueling growth, productivity and profits.The WiFi technology, which is governed by the IEEE 802.11 standards body, has played a key role in this transformation. In fact, thanks to WiFi, users can benefit of low cost access to high data rate wireless connectivity. The first version of the IEEE 802.11 protocol was released in 1997. IEEE 802.11 has been improved with different versions in order to enhance the throughput and support new technologies. WiFi networks are now experiencing the bandwidth-demanding media content as well as multiple WiFi devices for each user. As a consequence of this, WiFi 6, which is based on the IEEE 802.11ax standard, is focused on improving the efficiency of the radio link. However, there is a relatively modest increase in peak data rate too. In this thesis we have planned and realized a WiFi 6 network to replace wired connections in an enterprise environment. To do this the optimal access point placement problem has been taken into account, resulting in an improvement of the coverage. Subsequently, after the configuration from the controller, the performance of the new network has been tested in order to study if WiFi 6 can be used instead of wired connections.WiFi (Wireless Fidelity) is a popular wireless LAN technology. It provides broadband wireless connectivity to all the users in the unlicensed 2.4 GHz and 5 GHz frequency bands. Given the fact that the WiFi technology is much easier and cost-efficient to deploy, it is rapidly gaining acceptance as an alternative to a wired local area network. Nowadays the Wireless access to data is a necessity for everyone in the daily life. Considering the last 30 years, the unlimited access to information has transformed entire industries, fueling growth, productivity and profits.The WiFi technology, which is governed by the IEEE 802.11 standards body, has played a key role in this transformation. In fact, thanks to WiFi, users can benefit of low cost access to high data rate wireless connectivity. The first version of the IEEE 802.11 protocol was released in 1997. IEEE 802.11 has been improved with different versions in order to enhance the throughput and support new technologies. WiFi networks are now experiencing the bandwidth-demanding media content as well as multiple WiFi devices for each user. As a consequence of this, WiFi 6, which is based on the IEEE 802.11ax standard, is focused on improving the efficiency of the radio link. However, there is a relatively modest increase in peak data rate too. In this thesis we have planned and realized a WiFi 6 network to replace wired connections in an enterprise environment. To do this the optimal access point placement problem has been taken into account, resulting in an improvement of the coverage. Subsequently, after the configuration from the controller, the performance of the new network has been tested in order to study if WiFi 6 can be used instead of wired connections

Implementation of improvements of the Wi-Fi network of the RTBF and implementation of a Wi-Fi network for an “intelligent” building

Este Trabajo de Fin de Grado se ha realizado dentro de la Radio Televisión Belga Francófona (RTBF) en Bruselas. El objetivo de este proyecto es el diseño de una red Wi-Fi completamente confiable y de alto rendimiento para una de sus localizaciones. Para empezar, se completaron un estudio teórico y mediciones reales. La comparación entre el estudio teórico y práctico no estaba concluyente por lo que las predicciones teóricas se han modificado para corresponder a la realidad. Finalmente, la RTBF está construyendo un nuevo edificio en 2022 para el cual un estudio predictivo teórico se ha hecho para proporcionar una cantidad de puntos de accesos necesarios para una cobertura completa.This End-of-Grade work have been done inside the Francophone Belgian Radio-Television (RTBF) in Brussels. The goal of this Project is to design a fully reliable and performant Wi-Fi network for one of their localization. To begin with, a theorical study and real-life measurements were completed. The comparasion between the theorical and practical study was not concluding so the theorical predictions have been changed to correspond to reality. Finally, the RTBF is constructing a new building in 2022 for which a theorical predictive study have been done to provide the number of needed access points for a complete coverage.Grado en Ingeniería en Tecnologías de Telecomunicació

Comparing Downlink Capacity between Super Wi-Fi and Wi-Fi in Multi-Floored Indoor Environments

Department of Electrical EngineeringSuper Wi-Fi is a Wi-Fi-like service exploiting TV white spaces (WS) via the cognitive radio technology which is expected to achieve larger coverage than today???s Wi-Fi thanks to its superior propagation characteristics. Super Wi-Fi is currently being materialized as an international standard, IEEE 802.11af, targetting indoor and outdoor applications. This thesis demonstrates the potential of Super Wi-Fi in indoor environments by measuring its signal propagation characteristics and comparing them with those of Wi-Fi in the same indoor structure. Specifically, this thesis measures the wall and floor attenuation factors and path-loss distribution in 770 MHz and 2.4 GHz, and estimates the downlink capacity of Super Wi-Fi and Wi-Fi according to wide-accepted indoor path loss models. The experimental results reveal that TVWS signals can penetrate up to two floors and provide favorable coverage up to one floor above and below. In addition, TVWS can not only extend the coverage of Wi-Fi but also significantly mitigate shaded regions of Wi-Fi while achieving almost homogeneous data rates in the Wi-Fi???s coverage. The observed phenomena imply that Super Wi-Fi may be suitable for indoor applications with requirements of low-to-moderate data rates, extended horizontal and vertical coverage, and fair rate distribution within the service coverage.ope

Enhancing wireless communication system performance through modified indoor environments

This thesis reports the methods, the deployment strategies and the resulting system performance improvement of in-building environmental modification. With the increasing use of mobile computing devices such as PDAs, laptops, and the expansion of wireless local area networks (WLANs), there is growing interest in increasing productivity and efficiency through enhancing received signal power. This thesis proposes the deployment of waveguides consisting of frequency selective surfaces (FSSs) in indoor wireless environments and investigates their effect on radio wave propagation. The received power of the obstructed (OBS) path is attenuated significantly as compared with that of the line of sight (LOS) path, thereby requiring an additional link budget margin as well as increased battery power drain. In this thesis, the use of an innovative model is also presented to selectively enhance radio propagation in indoor areas under OBS conditions by reflecting the channel radio signals into areas of interest in order to avoid significant propagation loss. An FSS is a surface which exhibits reflection and/or transmission properties as a function of frequency. An FSS with a pass band frequency response was applied to an ordinary or modified wall as a wallpaper to transform the wall into a frequency selective (FS) wall (FS-WALL) or frequency selective modified wall (FS-MWALL). Measurements have shown that the innovative model prototype can enhance 2.4GHz (IEEE 802.11b/g/n) transmissions in addition to the unmodified wall, whereas other radio services, such as cellular telephony at 1.8GHz, have other routes to penetrate or escape. The FSS performance has been examined intensely by both equivalent circuit modelling, simulation, and practical measurements. Factors that influence FSS performance such as the FSS element dimensions, element conductivities, dielectric substrates adjacent to the FSS, and signal incident angles, were investigated. By keeping the elements small and densely packed, a largely angle-insensitive FSS was developed as a promising prototype for FSS wallpaper. Accordingly, the resultant can be modelled by cascading the effects of the FSS wallpaper and the ordinary wall (FSWALL) or modified wall (FS-MWALL). Good agreement between the modelled, simulated, and the measured results was observed. Finally, a small-scale indoor environment has been constructed and measured in a half-wave chamber and free space measurements in order to practically verify this approach and through the usage of the deterministic ray tracing technique. An initial investigation showing that the use of an innovative model can increase capacity in MIMO systems. This can be explained by the presence of strong multipath components which give rise to a low correlated Rayleigh Channel. This research work has linked the fields of antenna design, communication systems, and building architecture

ACUTA Journal of Telecommunications in Higher Education

In This Issue 5G\u27s Promise: 1,000 x Capacity, 1,000 x Challenges Higher-Speed WLANs About to Emerge State of the Residential Network 2013 LTE: The Next Wave of Wireless Evolution The 10 Most Costly Pitfalls of DAS Deployment and How to Avoid Them DAS on Campus: Solutions for Wireless Service Decision Criteria for Selecting a Wireless lntrusion Prevention System lnstitutional Excellence Award President\u27s Message From the CE

Borrowed Channel Relaying: A Novel Method to Improve Infrastructure Network Throughput

From a networking perspective, the chief impediment to throughput enhancement in infrastructure networks such as IEEE802.11 is the access point bottleneck: all traffic to, through, and from the network has to pass through this access point. When some clients experience poor channel conditions and therefore communicate at a lower data rate, this severely impacts the throughput of all clients in the network. Recently, multihop relaying in combination with leveraging multiple data rates was proposed to alleviate this problem. However, our experiments indicate that gains from these techniques are very small with realistic positioning of clients. Instead, we propose a novel scheme that combines relaying and multiple data rate capabilities with the concept of channel borrowing. Our protocol, BCR (Borrowed Channel Relaying), utilizes unused capacity from neighboring access points and is able to achieve network throughput gains of 20% to 60% depending on the scenario. Although we use 802.11 style networks to illustrate this concept, this general principle can be applied to any infrastructure network with receivers capable of tuning to more than one channel