Experimental characterization of the radio channel for systems with large bandwidth and multiple antennas

[SPA] Cada día son necesarias comunicaciones mejores y más eficientes, con mayores anchos de banda y mayores tasas de transferencias de datos. Por un lado los sistemas de múltiples antenas, MIMO, surgieron como una técnica para optimizar el uso de la potencia y el espectro. Por otro lado, los sistemas Ultra-Wideband, UWB, han ganado recientemente el interés de la comunidad científica por su gran ancho de banda combinado con su baja potencia de transmisión. A la hora de diseñar y testear nuevos dispositivos de comunicaciones inalámbricas, es esencial poseer un conocimiento preciso del canal de propagación por el que se propagan dichas señales. Esta tesis, se basa en el modelado del canal de propagación para sistemas de gran ancho de banda y múltiples antenas desde un punto de vista experimental. Primeramente se presentan las mejoras y desarrollos realizados en el ámbito de los sistemas de medida del canal, dado que es necesario disponer de equipos adecuados y precisos para realizar adecuadas medidas del canal. Seguidamente, se analiza el canal MIMO-UWB en interiores. Se realiza un análisis en profundidad de varios parámetros, especialmente parámetros de una antena como las pérdidas de propagación, el factor de polarización cruzada o la dispersión del retardo. Finalmente, la tesis particulariza el análisis del canal en un entorno especial como es el caso de túneles. Se realiza un análisis experimental de parámetros de una antena como multi antena para luego evaluar las prestaciones que pueden brindar varias técnicas de diversidad como es en el dominio de la frecuencia, la polarización, el espacio o el tiempo.[ENG] Wireless communications have become essential in our society [Rappaport, 1996], [Parsons, 2000]. Nowadays, people need to be connected everywhere and at any time, and demand faster and enhanced communications every day. New applications requires higher data rates and, therefore, higher bandwidths. On the one hand, Multiple-Input Multiple-Output (MIMO) systems were proposed as one solution to achieve higher data rates and optimize the use of the spectrum. On the other hand, more recently, systems with an ultra large bandwidth, and particularly Ultra-Wideband (UWB) systems, have gained the interest of the scientific community. Such interest is owing to the extremely high data rates offered and its possible coexistence with existing systems due to the its low transmitted power. However, this improvement in mobile communications involves the development and testing of new wireless communications systems. Precise knowledge of the radio channel is an essential issue to design this new devices and, thus, reach such improvement in wireless communications. In general, the modeling of the radio channel can be undertaken in two main ways: Theoretically, where the channel is characterized by means of simulations and theoretical approaches. - Experimentally, where the radio channel is characterized by means of the analysis of measurements carried out in real scenarios. This thesis is mainly focused on the experimental characterization of the radio channel for systems with large bandwidth and multiple antennas (MIMO). However, characterizing experimentally the MIMO wideband channel implies the availability of adequate and accurate channel sounders.Universidad Politécnica de CartagenaUniversité des Sciences et Technologies de Lille (USTL)Programa de doctorado en Tecnologías de la Información y Comunicacione

Energy Consumption Models For MISO-UWB and TR-MISO-UWB Systems

in this paper, an energy consumption model is developed and exploited to evaluate the electrical energy consumption of ultra-wideband impulse radio (UWB-IR) systems. We develop the energy consumption models and our comparative study, on the one hand, for a system based single-input single-output (SISO) configuration and a multiple-input single-output (MISO) and, on the other hand, for a time reversal TR-MISO configuration and for MISO alone configuration. We consider an indoor propagation environment based on the 802.15.4a channel model. The results show very different behaviors depending on the propagation conditions, the number of antennas used, or on the number of transmitted symbols. Using such a model, a radiofrequency designer can obtain significant inputs to optimally select an adequate configuration to design an adaptive energy-aware UWB-IR system

Antenna Designs Aiming at the Next Generation of Wireless Communication

Millimeter-wave (mm-wave) frequencies have drawn large attention, specically for the fifth generation (5G) of wireless communication, due to their capability to provide high data-rates. However, design and characterization of the antenna system in wireless communication will face new challenges when we move up to higher frequency bands. The small size of the components at higher frequencies will make the integration of the antennas in the system almost inevitable. Therefore, the individual characterization of the antenna can become more challenging compared to the previous generations.This emphasizes the importance of having a reliable, simple and yet meaningful Over-the-Air (OTA) characterization method for the antenna systems. To avoid the complexity of using a variety of propagation environments in the OTA performance characterization, two extreme or edge scenarios for the propagation channels are presented, i.e., the Rich Isotropic Multipath (RIMP) and Random Line-of-Sight (Random-LoS). MIMO efficiency has been defined as a Figure of Merit (FoM), based on the Cumulative Distribution Function (CDF) of the received signal, due to the statistical behavior of the signal in both RIMP and Random-LoS. Considering this approach, we have improved the design of a wideband antenna for wireless application based on MIMO efficiency as the FoM of the OTA characterization in a Random-LoS propagation environment. We have shown that the power imbalance and the polarization orthogonality plays major roles determining the 2-bitstream MIMO performance of the antenna in Random-LoS. In addition, a wideband dual-polarized linear array is designed for an OTA Random-LoS measurement set-up for automotive wireless systems. The next generation of wireless communications is extended throughout multiple narrow frequency bands, varying within 20-70 GHz. Providing an individual antenna system for each of these bands may not be feasible in terms of cost, complexity and available physical space. Therefore, Ultra-Wideband (UWB) antenna arrays, coveringmultiple mm-wave frequency bands represent a versatile candidate for these antenna systems. In addition to having wideband characteristics, these antennas should offer an easy integration capability with the active modules. We present a new design of UWB planar arrays for mm-wave applications. The novelty is to propose planar antenna layouts to provide large bandwidth at mm-wave frequencies, using simplified standard PCB manufacturing techniques. The proposed antennas are based on Tightly Coupled Dipole Arrays (TCDAs) concept with integrated feeding network

Ultra Wideband

Ultra wideband (UWB) has advanced and merged as a technology, and many more people are aware of the potential for this exciting technology. The current UWB field is changing rapidly with new techniques and ideas where several issues are involved in developing the systems. Among UWB system design, the UWB RF transceiver and UWB antenna are the key components. Recently, a considerable amount of researches has been devoted to the development of the UWB RF transceiver and antenna for its enabling high data transmission rates and low power consumption. Our book attempts to present current and emerging trends in-research and development of UWB systems as well as future expectations

State-of-the-art assessment of 5G mmWave communications

Deliverable D2.1 del proyecto 5GWirelessMain objective of the European 5Gwireless project, which is part of the H2020 Marie Slodowska- Curie ITN (Innovative Training Networks) program resides in the training and involvement of young researchers in the elaboration of future mobile communication networks, focusing on innovative wireless technologies, heterogeneous network architectures, new topologies (including ultra-dense deployments), and appropriate tools. The present Document D2.1 is the first deliverable of Work- Package 2 (WP2) that is specifically devoted to the modeling of the millimeter-wave (mmWave) propagation channels, and development of appropriate mmWave beamforming and signal processing techniques. Deliver D2.1 gives a state-of-the-art on the mmWave channel measurement, characterization and modeling; existing antenna array technologies, channel estimation and precoding algorithms; proposed deployment and networking techniques; some performance studies; as well as a review on the evaluation and analysis toolsPostprint (published version

Spatial channel characterization for smart antenna solutions in FDD wireless networks

This paper introduces a novel metric for determining the spatial decorrelation between the up- and down-link wireless bearers in frequency division duplex (FDD) networks. This metric has direct relevance to smart or adaptive antenna array base-station deployments in cellular networks, which are known to offer capacity enhancement when compared to fixed coverage solutions. In particular, the results presented were obtained from field trial measurement campaigns for both urban and rural scenarios, with the observations having a direct impact on the choice of down-link beamforming architecture in FDD applications. Further, it is shown that significant spatial decorrelation can occur in urban deployments for bearer separations as small as 5 MHz. Results are presented in terms of both instantaneous characteristics as well as time averaged estimates, thus facilitating the appraisal of smart antenna solutions in both packet and circuit switched network

Degree-of-freedom evaluation of six-port antenna arrays in a rich scattering environment

It has been proposed that six co-located antennas, namely three electric and three magnetic dipoles, can offer up to a six-fold capacity increase in wireless channels, relative to that of single antennas. In other words, six degrees of freedom (DOFs) can be supported by co-located six-port transmit and receive antenna arrays. However, due to the complexity in designing and measuring such a six-port antenna, to our knowledge, no experimental verification has yet been successfully performed. In this paper, the six DOFs hypothesis is experimentally verified at the 300 MHz band. The experiment involved the design and fabrication of two six-port arrays, and MIMO channel measurements in a rich scattering environment with these arrays

Performance of a crossed exponentially tapered slot antenna for UWB systems

WOS:000265937400006 (Nº de Acesso Web of Science)A compact printed antenna is described that exhibits adequate transient performance for ultrawideband (UWB) applications and it is further adequate for polarization diversity schemes. The antenna is based on an original combination of two crossed exponentially tapered slots plus a star-shaped slot to produce a stable radiation pattern with very stable polarization over the 3.1-10.6 GHz FCC assigned band. Results are confirmed with measurements. Figures of merit like output pulse fidelity and time window containing 90% of the transmitted energy are analyzed over the entire solid angle and showed to remain quite stable, in line with envisaged UWB system requirements. Compact dual-antenna arrangements are also analyzed in view of potential use for UWB multiple-input-multiple-output implementations