5G 3GPP-like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments

For the development of new 5G systems to operate in bands up to 100 GHz, there is a need for accurate radio propagation models at these bands that currently are not addressed by existing channel models developed for bands below 6 GHz. This document presents a preliminary overview of 5G channel models for bands up to 100 GHz. These have been derived based on extensive measurement and ray tracing results across a multitude of frequencies from 6 GHz to 100 GHz, and this document describes an initial 3D channel model which includes: 1) typical deployment scenarios for urban microcells (UMi) and urban macrocells (UMa), and 2) a baseline model for incorporating path loss, shadow fading, line of sight probability, penetration and blockage models for the typical scenarios. Various processing methodologies such as clustering and antenna decoupling algorithms are also presented.Comment: To be published in 2016 IEEE 83rd Vehicular Technology Conference Spring (VTC 2016-Spring), Nanjing, China, May 201

A Generalized Spatial Correlation Model for 3D MIMO Channels based on the Fourier Coefficients of Power Spectrums

Previous studies have confirmed the adverse impact of fading correlation on the mutual information (MI) of two-dimensional (2D) multiple-input multiple-output (MIMO) systems. More recently, the trend is to enhance the system performance by exploiting the channel's degrees of freedom in the elevation, which necessitates the derivation and characterization of three-dimensional (3D) channels in the presence of spatial correlation. In this paper, an exact closed-form expression for the Spatial Correlation Function (SCF) is derived for 3D MIMO channels. This novel SCF is developed for a uniform linear array of antennas with nonisotropic antenna patterns. The proposed method resorts to the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials. The resulting expression depends on the underlying arbitrary angular distributions and antenna patterns through the Fourier Series (FS) coefficients of power azimuth and elevation spectrums. The novelty of the proposed method lies in the SCF being valid for any 3D propagation environment. The developed SCF determines the covariance matrices at the transmitter and the receiver that form the Kronecker channel model. In order to quantify the effects of correlation on the system performance, the information-theoretic deterministic equivalents of the MI for the Kronecker model are utilized in both mono-user and multi-user cases. Numerical results validate the proposed analytical expressions and elucidate the dependence of the system performance on azimuth and elevation angular spreads and antenna patterns. Some useful insights into the behaviour of MI as a function of downtilt angles are provided. The derived model will help evaluate the performance of correlated 3D MIMO channels in the future.Comment: Accepted in IEEE Transactions on signal processin

Partner selection in indoor-to-outdoor cooperative networks: an experimental study

In this paper, we develop a partner selection protocol for enhancing the network lifetime in cooperative wireless networks. The case-study is the cooperative relayed transmission from fixed indoor nodes to a common outdoor access point. A stochastic bivariate model for the spatial distribution of the fading parameters that govern the link performance, namely the Rician K-factor and the path-loss, is proposed and validated by means of real channel measurements. The partner selection protocol is based on the real-time estimation of a function of these fading parameters, i.e., the coding gain. To reduce the complexity of the link quality assessment, a Bayesian approach is proposed that uses the site-specific bivariate model as a-priori information for the coding gain estimation. This link quality estimator allows network lifetime gains almost as if all K-factor values were known. Furthermore, it suits IEEE 802.15.4 compliant networks as it efficiently exploits the information acquired from the receiver signal strength indicator. Extensive numerical results highlight the trade-off between complexity, robustness to model mismatches and network lifetime performance. We show for instance that infrequent updates of the site-specific model through K-factor estimation over a subset of links are sufficient to at least double the network lifetime with respect to existing algorithms based on path loss information only.Comment: This work has been submitted to IEEE Journal on Selected Areas in Communications in August 201

Propagation measurement based study on relay networks

Von der nächsten Generation von Mobilfunksystemen erwartet man eine umfassende Versorgung mit breitbandigen Multimediadiensten. Um die dafür erforderliche flächendeckende Versorgung mit hohen Datenraten zu gewährleisten, können Relay-Netzwerke einen wesentlichen Beitrag liefern. Hierbei werden Netzwerkstationen mit Relay-Funktionalität in zellulare Netzwerke integriert. Diese Dissertation befasst sich mit der Untersuchung Relay-basierter Netzwerke unter Verwendung von Ausbreitungsmessungen. Die Arbeit deckt Fragen zur Kanalmodellierung, Systemevaluierung bis hin zur Systemverifikation ab. - Zunächst wird ein auf Funkkanalmessungen beruhendes experimentelles Kanalmodell für Relay-Netzwerke vorgestellt. Im Weiteren werden technische Verfahren für Mehrfachzugriffs-Relay-Netzwerke MARN diskutiert. Die erreichbare Systemleistung wurde unter Verwendung von Rayleigh-Kanälen innerhalb einer Systemsimulation bestimmt und im Anschluss mit realen Kanälen, die sowohl direkt aus Funkkanalmessungen als auch indirekt aus dem bereits erwähnten Kanalmodell abgeleitet wurden, verifiziert. Bisherige Arbeiten zur Modellierung breitbandiger Multiple-Input Multiple-Output (MIMO) Kanäle berücksichtigen nicht oder nur sehr stark vereinfacht die Langzeitkorrelationseigenschaften zwischen den Links und werden damit der vermaschten und räumlich weit verteilten Topologie von Relay-Netzwerken gerecht. In der vorliegenden Dissertation erfolgte daher eine experimentelle Untersuchung zu den Korrelationseigenschaften von Large-Scale-Parametern LSP, die unter Verwendung von Funkkanalmessdaten aus urbanen Umgebungen und aus Innenräumen abgeleitet wurden. Die Ergebnisse hierzu fanden Eingang in das vom WINNER-Projekt entwickelte Kanalmodell. Sie erlauben damit eine realistischere Simulation von Relay-unterstützten Netzen. Einen weiteren Schwerpunkt dieser Arbeit stellen technische Verfahren dar, die eine Erhöhung der Systemleistung in MARN mit unbekannter Interferenz UKIF versprechen. Im Einzelnen handelt es sich um die Mehrfachzugriffs-Kodierung MAC - die eine verbesserte Signaltrennung auf der Empfängerseite und eine Erhöhung des Datendurchsatzes erlaubt, den Entwurf eines Relay-Protokolls zur Erhöhung der Systemeffizienz, einen Minimum Mean Square Error (MMSE) Algorithmus zur Unterdrückung unbekannter Interferenzen bei Erhaltung der MAC-Signalstruktur mehrerer Mobilstationen MS, und ein fehlererkennungsbasiertes Signalauswahlverfahren zur Diversitätserhöhung. Die vorgenannten Verfahren werden in einer Systemsimulation zunächst mit Rayleigh-Kanälen evaluiert und demonstrieren die erzielbare theoretische Leistungssteigerung. Die Berücksichtigung realer Funkkanäle innerhalb der Systemsimulation zeigt allerdings, dass die theoretische Systemleistung so in der Realität nicht erreichbar ist. Die Ursache hierfür ist in den idealisierten Annahmen theoretischer Kanäle zu suchen. Für die Entwicklung künftiger Relay-Netzwerke bieten die in dieser Arbeit aufbereiteten Erkenntnisse hinsichtlich der Langzeitkorrelationseigenschaften zwischen den Links einen wertvollen Beitrag für die Abschätzung ihrer Systemleistung auf der Basis eines verbesserten Kanalmodells.Considering technological bases of next generation wireless systems, it is expected that systems can provide a variety of coverage requirements to support ubiquitous communications. To satisfy the requirements, an innovative idea, integrating network elements with a relaying capability into cellular networks, is one of the most promising solutions. The main topic of this dissertation is a propagation measurement based study on relay networks. The study includes three parts: channel modeling, performance evaluation, and verification. First of all, an empirical channel model for relay networks is proposed based on statistical analyses of measurement data. Then, advanced techniques for the throughput improvement and interference cancellation are proposed for Multiple Access Relay Networks (MARN) which are used as an example of relay networks. The performance of the considered MARN is evaluated for Rayleigh channels, and then verified for realistic channels, obtained from measurement data and from the experimental relay channel model as well. For relay channel modeling, the long-term correlation properties between links are of crucial importance due to the meshed-network topology. Although, there is a wide variety of research results for Multiple-Input Multiple-Output (MIMO) channel modeling available, the characterization of correlation properties has been significantly simplified or even completely ignored which motivates this research to be performed. In this dissertation, the experimental results of the correlation properties of Large Scale Parameters (LSP) are presented through the analysis on the real-field measurement data for both the urban and indoor scenarios. furthermore, the correlation properties have been fully introduced into the WINNER channel Model (WIM) for realistic relay channel simulations. As a further contribution of this dissertation, various advanced techniques are proposed for MARN in the presence of Unknown Interference (UKIF). Multiple Access Coding (MAC) is introduced as a multiple access technique. The use of MAC provides the signal separability at the receiver and improves throughput. Thereafter, high system resource efficiency can be achieved through relay protocol design. At the receiver, Minimum Mean Square Error (MMSE)-based spatial filtering is used to suppress UKIF while preserving multiple Mobile Station (MS)s’ MAC-encoded signal structure. Furthermore, an error detection aided signal selection technique is proposed for diversity increasing. The theoretical system performance with aforementioned techniques is simulated for Rayleigh channels. Thereafter, realistic channels are exploited for the performance verification. The gap between the theoretical performance and the realistic performance indicates that the assumptions made to the simplified Rayleigh-channels do not fully hold in reality. For the future relay system design, this work provides valuable information about the performance evaluation of relay networks in consideration of the correlation properties between links