A Novel Millimeter-Wave Channel Simulator and Applications for 5G Wireless Communications

This paper presents details and applications of a novel channel simulation software named NYUSIM, which can be used to generate realistic temporal and spatial channel responses to support realistic physical- and link-layer simulations and design for fifth-generation (5G) cellular communications. NYUSIM is built upon the statistical spatial channel model for broadband millimeter-wave (mmWave) wireless communication systems developed by researchers at New York University (NYU). The simulator is applicable for a wide range of carrier frequencies (500 MHz to 100 GHz), radio frequency (RF) bandwidths (0 to 800 MHz), antenna beamwidths (7 to 360 degrees for azimuth and 7 to 45 degrees for elevation), and operating scenarios (urban microcell, urban macrocell, and rural macrocell), and also incorporates multiple-input multiple-output (MIMO) antenna arrays at the transmitter and receiver. This paper also provides examples to demonstrate how to use NYUSIM for analyzing MIMO channel conditions and spectral efficiencies, which show that NYUSIM is an alternative and more realistic channel model compared to the 3rd Generation Partnership Project (3GPP) and other channel models for mmWave bands.Comment: 7 pages, 8 figures, in 2017 IEEE International Conference on Communications (ICC), Paris, May 201

Mobile 5G millimeter-wave multi-antenna systems

In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Universitat Politècnica de Catalunya's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink.Tesi en modalitat de compendi de publicacionsMassive antenna architectures and millimeter-wave bands appear on the horizon as the enabling technologies of future broadband wireless links, promising unprecedented spectral efficiency and data rates. In the recently launched fifth generation of mobile communications, millimetric bands are already introduced but their widespread deployment still presents several feasibility issues. In particular, high-mobility environments represent the most challenging scenario when dealing with directive patterns, which are essential for the adequate reception of signals at those bands. Vehicular communications are expected to exploit the full potential of future generations due to the massive number of connected users and stringent requirements in terms of reliability, latency, and throughput while moving at high speeds. This thesis proposes two solutions to completely take advantage of multi-antenna systems in those cases: beamwidth adaptation of cellular stations when tracking vehicular users based on positioning and Doppler information and a tailored radiation diagram from a panel-based system of antennas mounted on the vehicle. Apart from cellular base stations and vehicles, a third entity that cannot be forgotten in future mobile communications are pedestrians. Past generations were developed around the figure of human users and, now, they must still be able to seamlessly connect with any other user of the network and exploit the new capabilities promised by 5G. The use of millimeter-waves is already been considered by handset manufacturers but the impact of the user (and the interaction with the phone) is drastically changed. The last part of this thesis is devoted to the study of human user dynamics and how they influence the achievable coverage with different distributed antenna systems on the phone.Les arquitectures massives d'antenes i les bandes mil·limètriques apareixen a l'horitzó com les tecnologies que impulsaran els futurs enllaços sense fils amb gran ample de banda i prometen una eficiència espectral i velocitat de transmissió sense precedents. A la recent cinquena generació de comunicacions mòbils, les bandes mil·limètriques ja en són una part constitutiva però el seu desplegament encara presenta certes dificultats. En concret, els entorns d'alta mobilitat representen el major repte quan es fan servir diagrames de radiació directius, els quals són essencials per una correcta recepció del senyal en aquestes bandes. S'espera que les comunicacions vehiculars delimitin les capacitats de les xarxes en futures generacions degut al gran nombre d'usuaris simultanis i els requeriments estrictes en termes de fiabilitat, retard i flux de dades mentre es mouen a grans velocitats. Aquesta tesi proposa dues solucions per tal d'explotar al màxim els sistemes de múltiples antenes en tals casos: un ample de feix adaptatiu de les estacions bases quan estiguin fent el seguiment d'un vehicle usuari basat en informació de la posició i el Doppler i el disseny d'un diagrama de radiació adequat al costat del vehicle basat en una estructura de múltiples panells muntats a l'estructura del mateix. A més de les estacions base i els vehicles, un tercer element que no pot ser obviat en aquests escenaris són els vianants. Les generacions anteriors van ser desenvolupades al voltant de la figura d'usuaris humans i ara han de seguir tenint la capacitat de connexió ininterrumpuda amb la resta d'usuaris i explotar les capacitats de 5G. L'ús de frequències mil·limètriques també es té en compte en la fabricació de telèfons mòbils però l'impacte de l'usuari és completament diferent. La última part de la tesis tracta l'estudi de les dinàmiques de l'usuari humà i com influeixen en la cobertura amb diferent sistemes distribuïts d'antenes.Postprint (published version

Sub-6 GHz channel modelling and evaluation in indoor industrial environments

This paper presents sub-6 GHz channel measurements using a directional antenna at the transmitter and a directional or omnidirectional antenna at the receiver at 4.145 GHz in sparse and dense industrial environments for a line-of-sight scenario. Furthermore, the first measured over-the-air error vector magnitude (EVM) results depending on different 5G new radio modulation and coding schemes (MCSs of16 QAM, 64 QAM and 256 QAM) are provided. From the measurement campaigns, the path loss exponents (PLE) using a directional and an omnidirectional antenna at the receiver in the sparse and the dense environment are 1.24/1.39 and 1.35/1.5, respectively. PLE results are lower than the theoretical free space PLE of 2, indicating that indoor industrial environments have rich multipaths. The measured power delay profiles show the maximum root mean square (RMS) delay spreads of 11 ns with a directional antenna and 34 ns with an omnidirectional antenna at the receiver in a sparse industrial environment. However, in a dense industrial environment the maximum RMS delay spreads are significantly increased: maximum RMS delay spreads range from 226 to 282 ns for the omnidirectional and the directional antenna configuration. EVM measurements show that to increase coverage and enable higher MCS modes to be used for reliable data transmission, in both industrial environments using a directional antenna at the transmitter and the receiver is required. The large-scale path loss models, multipath time dispersion characteristics and EVM results provide insight into the deployments of 5G networks operating at sub-6 GHz frequency bands in different industrial environments

Pervasive wireless channel modeling theory and applications to 6G GBSMs for all frequency bands and all scenarios

In this paper, a pervasive wireless channel modeling theory is first proposed, which uses a unified channel modeling method and a unified equation of channel impulse response (CIR), and can integrate important channel characteristics at different frequency bands and scenarios. Then, we apply the proposed theory to a three dimensional (3D) space-time-frequency (STF) non-stationary geometry-based stochastic model (GBSM) for the sixth generation (6G) wireless communication systems. The proposed 6G pervasive channel model (6GPCM) can characterize statistical properties of channels at all frequency bands from sub-6 GHz to visible light communication (VLC) bands and all scenarios such as unmanned aerial vehicle (UAV), maritime, (ultra-)massive multiple-input multiple-output (MIMO), reconfigurable intelligent surface (RIS), and industry Internet of things (IIoT) scenarios. By adjusting channel model parameters, the 6GPCM can be reduced to various simplified channel models for specific frequency bands and scenarios. Also, it includes standard fifth generation (5G) channel models as special cases. In addition, key statistical properties of the proposed 6GPCM are derived, simulated, and verified by various channel measurement results, which clearly demonstrates its accuracy, pervasiveness, and applicability

Millimeter wave radio channels: properties, multipath modeling and simulations

Based on the characterization of realistic radio channels, results presented in this dissertation lead towards an understanding that when moving up to the higher frequencies, frequency itself does not play a significant role in defining the channel modeling methodology. In fact, how a propagation channel is illuminated is of fundamental importance. Therefore, millimeter wave (mmWave) system properties such as a high antenna directivity and system bandwidth are shown to have a great influence on the channel model definition. In this thesis, a fundamental assumption made in the state-of-the-art millimeter wave wireless channel models is challenged. It has been shown that Rayleigh-Rice fading assumption made in the state-of-the-art channel models for resolvable channel taps does not remain valid. This is mainly due to the sparse multipath illumination caused by high antenna directivity and high bandwidth of a mmWave system.Studies presented in this thesis are based on the characterization of realistic radio channels obtained from exhaustive channel sounding campaigns. Mainly, three fundamental problems of wireless channel modelling have been investigated for millimetre wave (mmWave) radio channel modelling application, namely (i) Frequency dependence of propagation, (ii) Impact of antenna directivity on the channel model definition, and (iii) Impact of system bandwidth on the radio channel modelling. A detailed description of these problems is as follows: (i) Frequency Dependence of Propagation. Multi-band measurement campaigns arecarried out using directional antennas which do an omni-directional scan of the propagation environment. During the measurements, Tx-Rx systems are placed at fixed positions and the propagation environment remained as static as possible. Using synthesized omni-directional power delay profiles (PDPs), we aim to investigate if there exists a frequency dependency in the multipath dispersion statistics, e.g. delay and angular spreads. (ii) Impact of Antenna Directivity on the Channel Model Definition. Small-scale fading measurements are carried out which emulate a scenario, where a radio communication link is established through a single multipath cluster which is illuminated using antennas with different Half Power Beam Widths (HPBW). The major goal here is to investigate the impact of spatial multipath filtering on the small-scale fading due to high antenna directivity. In particular, the impact on variations in the receive signal strength and the validity of narrowband wide-sense stationary assumption (both in time and frequency domains) is investigated. (iii) Impact of System Bandwidth on the Radio Channel Modelling. Small-scale fading measurements are used to illuminate multipath clusters in a lecture room scenario. The primary objective is to investigate the impact of high system bandwidth on variations in the receive signal strength, randomness in the cross-polarization power ratio (XPR) and richness of the multipath scattering. Based on the characterization of realistic radio channels, results presented in this dissertation lead towards an understanding that when moving up to the higher frequencies, frequency itself does not play a significant role in defining the channel modelling methodology. In fact, how a propagation channel is illuminated is of fundamental importance. Therefore, mmWave system properties such as a high antenna directivity and system bandwidth are shown to have a high influence on the channel model definition. In general, fade depth scaling as a function of system bandwidth is quite well understood. We demonstrate that, the high antenna directivity of mmWave systems result in a further reduction in the fading depth. In addition, we explore some new directions to this line of research which are based on the second-order statistical analysis of the channel impulse response (CIR) vector. Our results emphasize that, fading statistics of resolvable channel taps in a mmWave radio channel cannot be modelled as Rayleigh-Rice distributed random variables. This is primarily due to the fact that channels with sparse scattering conditions are illuminated due to high antenna directivity and bandwidth of mmWave systems. Consequently, the complex Gaussian random variable assumption associated with Rayleigh-Rice fading distributions does not remain valid. Further, it has been demonstrated that, high antenna directivity and bandwidth of mmWave systems also raise a question mark on the validity of wide-sense stationary (WSS) assumption in the slow-time domain of mmWave radio channels. Results presented in this contribution are novel and they provide theoretically consistent insights into the measured radio channel.In dieser Arbeit werden drei grundlegende Probleme der Modellierung von Drahtloskanalen fur die Anwendung bei der Funkkanalmodellierung im Millimeterwellenbereich (mmWave) untersucht, namlich (i) die Frequenzabhangigkeit der Ausbreitung, (ii) der Einfluss der Antennenrichtwirkung auf die Definition des Kanalmodells und (iii) der Einfluss der Systembandbreite auf die Funkkanalmodellierung. Die detaillierte Beschreibung dieser Probleme lautet wie folgt: (i) Frequenzabhangigkeit der Ausbreitung. Mehrband-Messkampagnen werden mitRichtantennen durchgefuhrt, die eine omnidirektionale Abtastung der Ausbreitungsumgebung vornehmen. Wahrend der Messungen werden die Tx-Rx-Systeme an festen Positionen platziert und die Ausbreitungsumgebung bleibt so statisch wie moglich. Mit Hilfe von synthetisierten omnidirektionalen Verzogerungs-Leistungsprofilen soll untersucht werden, ob es eine Frequenzabhangigkeit in der Mehrwegeausbreitungsstatistik gibt, z.B. in der Verzogerung und der Winkelspreizung. (ii) Einfluss der Antennenrichtwirkung auf die Definition des Kanalmodells. Es werden Messungen des schnellen Schwunds durchgefuhrt, die ein Szenario emulieren, bei dem eine Funkverbindung uber ein einzelnes Mehrwege-Cluster aufgebaut wird, das mit Antennen mit unterschiedlichen Strahlbreiten ausgeleuchtet wird. Das Hauptzielist hier die Untersuchung des Einflusses der raumlichen Filterung auf den schnellen Schwund aufgrund der hohen Antennenrichtwirkung. Insbesondere wird die Auswirkung auf Variationen der Empfangssignalstarke und die Gultigkeit der Annahme der schmalbandigen Stationaritat im weiteren Sinne (sowohl im Zeit- als auch im Frequenzbereich) untersucht. (iii) Einfluss der Systembandbreite auf die Funkkanalmodellierung. Messungen desschnellen Schwunds werden verwendet, um Mehrwege-Cluster in einem Horsaal-Szenario auszuleuchten. Das primare Ziel ist es, den Einfluss einer hohen Systembandbreite auf die Variationen der Empfangssignalstarke, die Zufalligkeit des Kreuzpolarisationsverhaltnisses und die Reichhaltigkeit der Mehrwegstreuung zu untersuchen. Basierend auf der Charakterisierung realistischer Funkkanäle führen die in dieser Dissertation vorgestellten Ergebnisse zu dem Verständnis, dass beim Ubergang zu höheren Frequenzen die Frequenz x selbst keine signifikante Rolle bei der Definition der Kanalmodellierungsmethodik spielt. Vielmehr ist es von grundlegender Bedeutung, wie ein Ausbreitungskanal ausgeleuchtet wird. Daher zeigt sich, dass mmWave-Systemeigenschaften wie eine hohe Antennenrichtcharakteristik und Systembandbreite einen hohen Einfluss auf die Definition des Kanalmodells haben. Im Allgemeinen ist die Skalierung der Schwundtiefe als Funktion der Systembandbreite ziemlich gut verstanden. Wir zeigen, dass die hohe Antennenrichtwirkung von mmWave-Systemen zu einer weiteren Reduzierung der Schwundtiefe führt. Zusätzlich erforschen wir einige neue Richtungen in diesem Forschungsbereich, die auf der Analyse der Statistik zweiter Ordnung des Kanalimpulsantwort-Vektors basieren. Unsere Ergebnisse unterstreichen, dass die Schwund-Statistiken der auflösbaren Kanalabgriffe in einem mmWave-Funkkanal nicht als Rayleigh-Rice-verteilte Zufallsvariablen modelliert werden können. Dies liegt vor allem daran, dass durch die hohe Antennenrichtwirkung und Bandbreite von mmWave-Systemen Kanale mit spärlichen Streubedingungen ausgeleuchtet werden. Folglich ist die Annahme komplexer Gaus’scher Zufallsvariablen, die mit Rayleigh-Rice Schwundverteilungen verbunden ist, nicht mehr gültig. Des Weiteren wird gezeigt, dass die hohe Antennenrichtwirkung und Bandbreite von mmWave-Systemen auch die Gültigkeit der Annahme von Stationarität im weiteren Sinne im Slow-Time-Bereich von mmWave-Funkkanälen in Frage stellt. Die in diesem Beitrag vorgestellten Ergebnisse sind neuartig und bieten theoretisch konsistente Einblicke in den gemessenen Funkkanal

Terahertz Wireless Channels: A Holistic Survey on Measurement, Modeling, and Analysis

Terahertz (0.1-10 THz) communications are envisioned as a key technology for sixth generation (6G) wireless systems. The study of underlying THz wireless propagation channels provides the foundations for the development of reliable THz communication systems and their applications. This article provides a comprehensive overview of the study of THz wireless channels. First, the three most popular THz channel measurement methodologies, namely, frequency-domain channel measurement based on a vector network analyzer (VNA), time-domain channel measurement based on sliding correlation, and time-domain channel measurement based on THz pulses from time-domain spectroscopy (THz-TDS), are introduced and compared. Current channel measurement systems and measurement campaigns are reviewed. Then, existing channel modeling methodologies are categorized into deterministic, stochastic, and hybrid approaches. State-of-the-art THz channel models are analyzed, and the channel simulators that are based on them are introduced. Next, an in-depth review of channel characteristics in the THz band is presented. Finally, open problems and future research directions for research studies on THz wireless channels for 6G are elaborated.Comment: to appear in IEEE Communications Surveys and Tutorial