Estudio experimental de algoritmos espacio-temporales para sistemas multiantena en túneles

[SPA] Las comunicaciones inalámbricas se han convertido hoy en día en una herramienta imprescindible en la sociedad en la que vivimos. En la actualidad los hábitos de consumo en las comunicaciones inalámbricas exigen aumentar la capacidad para transmitir contenidos multimedia. Día a día se trabaja en conseguir mejorar las prestaciones de estos sistemas inalámbricos y así poder afrontar dichas necesidades. Por ello, surgen los sistemas conocidos como Multiple-Input Multiple-Output (MIMO), que utilizan múltiples antenas en transmisión y múltiples antenas en recepción, permitiendo así alcanzar eficiencias espectrales mucho mayores a las alcanzadas en los sistemas convencionales. Por otro lado, en los últimos años se ha dado mucha importancia a poder comunicarse en entornos especiales, como es el caso de los túneles donde la naturaleza de los fenómenos físicos que permiten la propagación de las ondas es diferente al de otros entornos. En este tipo de entornos la energía es conducida por un medio guiado, de tal forma que la energía llega al receptor con un ángulo muy reducido en comparación con otros entornos. Además, la comunicación debe ser continua, fiable y de alta capacidad. Así pues, para cubrir dichas necesidades esta tesis está enmarcada en el estudio de los entornos tipo túnel, centrándose en el comportamiento y el rendimiento de los algoritmos espacio-temporales, ya que en este tipo de entornos se ha investigado muy poco sobre ello. Por ello, el objetivo principal de esta tesis es estudiar detalladamente, tanto de forma teórica como experimental, el comportamiento de los sistemas MIMO en túneles. Para ello se estudian los algoritmos más representativos de los sistemas multiantena: el algoritmo Vertical Bell Labs Space Time (VBLAST), los códigos Orthogonal Space Time Block Codes (OSTBC) y los códigos Quasy-Orthogonal Space Time Block Codes (QSTBC). El rendimiento de estos algoritmos, según la tasa de error de bit (BER, Bit Error Rate), se relaciona con las propiedades intrínsecas del canal radio tanto en banda estrecha como en banda ancha. [ENG] Wireless communications have become an indispensable tool in the society in which we live. In fact, the consumption habits of wireless communications require increasing capacity to transmit multimedia contents. Therefore, in order to meet these needs, work is continually being carried out in order to achieve the best performance possible from these wireless systems. The Multiple-Input Multiple-Output (MIMO) systems appear to achieve greater spectral efficiencies than the convectional systems. Furthermore, in recent years, communications in special contexts have acquired great importance. This thesis is focused on an environment type tunnel where the nature of the physical phenomena is different from other contexts. The energy is driven by a guided environment, therefore the energy arrives at the receiver with a smaller angle than in other environments. In addition, a continuous, reliable and effective communication is demanded. To meet the needs mentioned above, this thesis analyses the performance of space-time algorithms in tunnels. The main objective of this thesis is to study in detail both theoretically and experimentally the behaviour of the MIMO systems in tunnels combined with space-time algorithms. Moreover, this study covers both narrow and wide bands. The studied algorithms are the most representative: the Vertical Bell Labs Space Time (VBLAST), the Orthogonal Space Time Block Code (OSTBC) and the Quasy-Orthogonal Space Time Block Code (QSTBC). The performances in terms of Bit Error Rate (BER) have been compared, assuming a fixed bit rate, and interpreted from the MIMO channel characteristics.[ENG] Wireless communications have become an indispensable tool in the society in which we live. In fact, the consumption habits of wireless communications require increasing capacity to transmit multimedia contents. Therefore, in order to meet these needs, work is continually being carried out in order to achieve the best performance possible from these wireless systems. The Multiple-Input Multiple-Output (MIMO) systems appear to achieve greater spectral efficiencies than the convectional systems. Furthermore, in recent years, communications in special contexts have acquired great importance. This thesis is focused on an environment type tunnel where the nature of the physical phenomena is different from other contexts. The energy is driven by a guided environment, therefore the energy arrives at the receiver with a smaller angle than in other environments. In addition, a continuous, reliable and effective communication is demanded. To meet the needs mentioned above, this thesis analyses the performance of space-time algorithms in tunnels. The main objective of this thesis is to study in detail both theoretically and experimentally the behaviour of the MIMO systems in tunnels combined with space-time algorithms. Moreover, this study covers both narrow and wide bands. The studied algorithms are the most representative: the Vertical Bell Labs Space Time (VBLAST), the Orthogonal Space Time Block Code (OSTBC) and the Quasy-Orthogonal Space Time Block Code (QSTBC). The performances in terms of Bit Error Rate (BER) have been compared, assuming a fixed bit rate, and interpreted from the MIMO channel characteristics.Universidad Politécnica de CartagenaTecnologías de la Información y Comunicacione

Experimental study of MIMO-OFDM transmissions at 94 GHz in indoor environments

Millimeter wave (mm-wave) frequencies have been proposed to achieve high capacity in 5G communications. Although meaningful research on the channel characteristics has been performed in the 28, 38and 60 GHz bands ─in both indoor and short-range scenarios─,only a small number of trials (experiments) have been carried out in other mm-wave bands. The objective of this work is to study the viability and evaluate the performance of the 94 GHz frequency band for MIMO-OFDM transmission in an indoor environment. Starting from a measurement campaign, the performance of MIMO algorithms is studied in terms of throughput for four different antenna configurations.This work was supported in part by the Ministerio de Economía y Competitividad MINECO, Spain under Grant TEC2016-78028-C3-2-P, and in part by the European FEDER funds

Millimeter Wave MISO-OFDM Transmissions in an Intra-Wagon Environment

[EN] In this paper, the maximum achievable throughput is analyzed in the intra-wagon channel when multiple-input single-output (MISO) and orthogonal frequency division multiplexing (OFDM), MISO-OFDM, techniques are used. This analysis is performed from real wideband propagation channel measurements at 28 and 37 GHz, two potential frequency bands to deploy the future fifth-generation (5G) wireless communications networks. Four different scenarios in terms of the access point (AP) and user equipment (UE) positions inside the wagon have been considered, using 4 and 8 antennas at the AP. The performance of both quasi-orthogonal space-time block code (QSTBC), combined with Hadamard matrices, and transmit beamforming techniques is studied and evaluated from simulation results. The simulation results take into account the signal-to-noise ratio (SNR) and the antenna correlation for each antenna array configuration at the AP. These results provide useful insight to better understand the intra-wagon channel properties and deploy the future 5G wireless networks in this particular scenario at mmWave frequencies, where high-data-rates are expected to support different types of digital applications.This work was supported in part by the Ministerio de Economia y Competitividad MINECO, Spain, under Grant TEC2016-78028C3-2-P and Grant TEC2017-86779-C2-2-R and in part by the European FEDER Funds.Sanchis Borrás, C.; Molina-García-Pardo, J.; Rubio Arjona, L.; Pascual-García, J.; Rodrigo Peñarrocha, VM.; Juan Llacer, L.; Reig, J. (2021). Millimeter Wave MISO-OFDM Transmissions in an Intra-Wagon Environment. IEEE Transactions on Intelligent Transportation Systems. 22(8):4899-4908. https://doi.org/10.1109/TITS.2020.2983028S4899490822

Millimeter Wave Channel Measurements in an Intra-Wagon Environment

© 2019 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."[EN] In this correspondence, useful measurement results of the propagation channel characteristics in an intra-wagon environment at millimeter wave (mmWave) frequencies are presented. The measurements were collected inside an underground convoy from 25 to 40 GHz in the frequency domain. A broadband radio over fiber (RoF) link was used in order to avoid the high losses introduced by cables at these frequencies, thus allowing long distances between the transmitter and receiver antennas. Values of the path loss exponent and delay spread are reported at the potential 26, 28 and 38 GHz bands to deploy the future fifth-generation (5G) systems. These results allow us to have a better knowledge of the path loss and time dispersion characteristics of the propagation channel in this particular environment, characterized by rich-scattering with long delays.This work was supported by the Ministerio de Economia, Industria y Competitividad of the Spanish Government under the National Projects TEC2016-78028-C3-2-P and TEC2017-86779-C2-2-R, through the Agencia Estatal de Investigacion (AEI) and the Fondo Europeo deDesarrollo Regional (FEDER). The review of this article was coordinated by Prof. J. F. Paris. The authors would like to thank the staff of FGV who have facilitated the realization of the measurements campaing, in particular J. Iserte Villalba and F. M. Brox López.Rubio Arjona, L.; Rodrigo Peñarrocha, VM.; Molina-García-Pardo, JM.; Juan Llacer, L.; Pascual Garcia, J.; Reig, J.; Sanchis Borrás, C. (2019). Millimeter Wave Channel Measurements in an Intra-Wagon Environment. IEEE Transactions on Vehicular Technology. 68(12):12427-12431. https://doi.org/10.1109/TVT.2019.2947205S1242712431681

Evaluación experimental de un sistema MIMO-OFDM basado en IEEE802.15.3.c en interiores

En este trabajo se presenta un estudio experimental para un sistema MIMO-OFDM (Multiple-Input Multiple-Output, Orthogonal Frequency Division Multiplexing), basado en el estándar 802.15.3c. La característica principal de este sistema es el uso de la banda milimétrica (60 GHz), así como el uso de múltiples antenas. Se midió el canal radioeléctrico con un analizador de redes, y se ha analizado el rendimiento de algoritmos espacio temporal sobre la capa física real. En el entorno de medida, se han obtenido tasas de transferencia de hasta 5,77 Gbit/s.Asociación de Jóvenes Investigadores de Cartagena, (AJICT). Universidad Politécnica de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT, (ETSII). Escuela Técnica Superior de Ingeniería Agronónica, (ETSIA), Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos, Canales, y Puertos y de Ingeniería de Minas, (EICM). Fundación Séneca, Agencia Regional de Ciencia y Tecnología. Parque Tecnológico de Fuente Álamo. Grupo Aquilin

Transmisiones a 28GHz y 37GHz en interiores de trenes aplicando técnicas MISO-OFDM

[EN] This paper analyses a simulation of performance in an intra-wagon environment based on four scenarios. The 28 GHz and the 37 GHz bands are assessed for the use of 5G millimeter (mmWave) communications. The main objective was to analyses different multiple-input single-output orthogonal frequency division multiplexing (MISO-OFDM) techniques such as Hadamard quasiorthogonal space-time block code (HQSTBC) and transmit beamforming to analyze the throughput achieved as a function of the signal-to-noise ratio (SNR) applied. Starting from a measurement campaign, the performance is analyzed by scenario, applied band and in terms of the two algorithms used. In addition, the results are simulated with 4 and 8 transmitting antennas.Este trabajo ha sido financiado en parte por los proyectos PID2019-107885GB-C33 y TEC2017-86779-C2-2-R (AEI/FEDER, UE). Agradecer a Julia Iserte Villalba y Francisco M. Brox Lopez (personal de FGV) por facilitar la campaña de medidas.Sanchis Borrás, C.; Molina-García-Pardo, J.; Rubio Arjona, L.; Pascual García, J.; Rodrigo Peñarrocha, VM.; Llacer, LJ.; Reig, J. (2021). Transmisiones a 28GHz y 37GHz en interiores de trenes aplicando técnicas MISO-OFDM. Íñigo Cuiñas Gómez. 1-4. http://hdl.handle.net/10251/1910781

Análisis de V-BLAST a partir de medidas en un tunel

In this work we use the experimental data from an extensive 8x8 MIMO (Multiple-Input Multiple-Output) wideband (2.8GHz-5GHz) measurement campaign in a semicircular tunnel to study the impact of different multiantenna signal processing approaches such as the MMSEVBLAST algorithm. We focus in the 3 and 5 GHz bands, and at different distances from the transmitter and the receiver. Simulation results are exhibited, showing the relation between SNR (Sygnal to Noise Ratio) and SER (Symbol Error Rate).Este trabaja ha sido parcialmente financiado por el Ministerio de Educación y Ciencia (TEC2007-66698-C04-04/TCM) y la Fundación Séneca de Murcia (03133/PI/05)

Massive MIMO Indoor Transmissions at 38 and 65 GHz Applying Novel HBF Techniques for 5G

The 5G Infrastructure Public Private Partnership (5GPPP) has recently published a white paper about 5G service indoors, since up to now, it had mainly focused on the outdoors. In an indoor environment, the requirements are different since the propagation mechanism differs from other scenarios. Furthermore, previous works have shown that space frequency block code (SFBC) techniques applied to multiple antennas improve performance compared to single-input single-output (SISO) systems. This paper presents an experimental study in an indoor environment regarding the performance of a massive multiple-input multiple-output (mMIMO) millimeter-wave (mmWave) system based on the 5G New Radio (NR) standard in two frequency bands. In a first step, the 38 and 65 GHz bands are compared by applying a low-complexity hybrid beamforming (HBF) algorithm. In a second step, the throughput and the maximum achievable distance are studied using a new algorithm that combines the SFBC technique and HBF. Results show, at 38 GHz with HBF and aggregated bandwidths (4 × 100 MHz), a maximum throughput of 4.30 Gbit/s up to 4.1 m. At 65 GHz, the SFBC + HBF algorithm improves the communication distance by 1.34, 1.61, or 1.75 m for bandwidths of 100, 200, or 400 MHz, respectively

Análisis del canal radio para aplicaciones UWB

Results from a MIMO-UWB measurement campaigns are presented in this contribution. We focus in the 2-5 GHz. For immediate commercial applications UWB propagation is mainly interesting for the 3-5 GHz range [1]. We present experimental validation of the assumption that the path gain function can be modelled independently from the distance and the frequency, as well as some results on the rms delay spread showing a positive increment with distance in the four situations studied.Este trabajo ha sido parcialmente financiado por el Ministerio de Educación y Ciencia (TEC2007-66698-C04-04/TCM) y la Fundación Séneca de Murcia (03133/PI/05)

Wireless Channel Analysis Between 25 and 40 GHz in an Intra-Wagon Environment for 5G Using a Ray-Tracing Tool

[EN] Metro and railway systems are one of the most used transportation systems for people in almost all countries. Nevertheless, the access to high throughput wireless services is still very limited inside the wagons (cars). A deep analysis of the wireless channel inside wagons is needed to deploy new efficient and high throughput networks as the ones provided by fifth-generation (5G) systems. Although several works have analyzed the intra-wagon channel, some limitations are usually present: only certain user equipment-access point situations were considered, the number of studied propagation mechanisms was limited, and only some channel parameters were extracted. For these reasons, in this work the wireless channel in an intra-wagon environment is thoroughly analyzed using simulations performed with a ray-tracing tool calibrated and validated with wideband measurements. Thanks to the accurate ray-tracing tool the main replicas are identified in different typical user equipment-access point positions; the contribution of each propagation mechanism to the total power is extracted; and the angular spread in azimuth and elevation for the direction of arrival and departure are obtained. This analysis is performed in the frequency range from 25 to 40 GHz, where spectrum for several 5G bands has been already allocated.This work was supported in part by the Ministerio de Ciencia e Innovacion of the Spanish Government through the National Projects under Grant PID2019-107885GB-C33 and in part by the Agencia Estatal de Investigacion (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) under Grant PID2020-119173RB-C21.Pascual García, J.; Rubio Arjona, L.; Rodrigo Peñarrocha, VM.; Juan-Llácer, L.; Molina-García-Pardo, JM.; Sanchis-Borrás, C.; Reig, J. (2022). Wireless Channel Analysis Between 25 and 40 GHz in an Intra-Wagon Environment for 5G Using a Ray-Tracing Tool. IEEE Transactions on Intelligent Transportation Systems. 23(12):24621-24635. https://doi.org/10.1109/TITS.2022.31991592462124635231