Outage Analysis of Hybrid Satellite-Terrestrial Cooperative Network with Best Relay Selection

In this paper, we study the performance of a downlink hybrid satellite-terrestrial cooperative network. The decode-andforward scheme is used and a selection of the best relay terminal is implemented. In this proposed system, a two time-slot scenario is considered. The first time slot is used by the satellite for broadcasting the information to the terrestrial relays and the destination. In the second time slot, only the best relay which provides the maximal received signal-to-noise (SNR) ratio at the destination is selected for forwarding the information. Then, both signals are combined using the maximum ratio combining (MRC) technique. The analytical expression of the outage probabiliy is evaluated and is then verified with the simulation. The results show that our analytical expression matched well to the simulation results at the high SNR regime

Proceedings of the 19th NASA Propagation Experimenters Meeting (NAPEX 19) and the 7th Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop (APSW 7)

The NASA Propagation Experimenters Meeting (NAPEX), supported by the NASA Propagation Program, is convened annually to discuss studies made on radio wave propagation by investigators from domestic and international organizations. NAPEX 19 was held on 14 Jun. 1995, in Fort Collins, Colorado. Participants included representatives from Canada, Japan, and the United States, including researchers from universities, government agencies, and private industry. The meeting focused on mobile personal satellite systems and the use of 20/30-GHz band for fixed and mobile satellite applications. In total, 18 technical papers were presented. Following NAPEX 19, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop 7 (APSW 7) was held on 15-16 Jun. 1995, to review ACTS propagation activities with emphasis on the experimenters' status reports and dissemination of propagation data to industry

Proceedings of the Fifteenth NASA Propagation Experimenters Meeting (NAPEX 15) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

The NASA Propagation Experimenters Meeting (NAPEX), supported by the NASA Propagation Program, is convened annually to discuss studies made on radio wave propagation by investigators from domestic and international organizations. The meeting was organized into three technical sessions. The first session was dedicated to Olympus and ACTS studies and experiments, the second session was focused on the propagation studies and measurements, and the third session covered computer-based propagation model development. In total, sixteen technical papers and some informal contributions were presented. Following NAPEX 15, the Advanced Communications Technology Satellite (ACTS) miniworkshop was held on 29 Jun. 1991, to review ACTS propagation activities, with emphasis on ACTS hardware development and experiment planning. Five papers were presented

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Investigation of the effects of cloud attenuation on satellite communication systems

The aim of this project is to investigate the attenuation due to clouds at 20- 50GHz; to develop an accurate long-term prediction model of cloud attenuation applicable to slant-path links and evaluate the impact of cloud attenuation dynamics on the design of future portable EHF earth-space systems. Higher frequencies offer several advantages, for example, greater bandwidth and immunity to ionospheric effects. The EHF band is being targeted for the launch of earth-space communication systems to provide global delivery of bandwidthintensive services (e.g. interactive HDTV, broadband internet access and multimedia services, television receive-only, etc.) to portable terminal units. Since spectrum shortage and terminal bulk currently preclude the realization of these breakthrough-broadband wireless communication services at lower frequencies, a better understanding is needed in order to optimize their usage. One major obstacle in the design of EHF earth-space communication systems is the large and variable signal attenuation in the lower atmosphere, due to a range of mechanisms including attenuation (and scattering) due to clouds and rain, tropospheric scintillation caused by atmospheric turbulence and variable attenuation by atmospheric gasses. In particular, cloud attenuation becomes very significant at EHF. In this thesis, we start with an overview of literature review in the first chapter. Followed next by the theory and description of accepted-up to date- cloud attenuation models in the field (chapter 2). Then followed up by a description of the pre-processing, validations, sources and assumptions made in order to conduct the analysis of the cloud attenuation in this work (chapter 3). Afterwards, a comprehensive analysis of Meteorological and local tropospheric degradation was carried out (chapter 4). That was followed by an overview of cloud fade statistics and suggested methods to counter their effects (chapter 5). And finally the improved cloud attenuation model and the enhancement of the currently accepted cloud attenuation model (ITU-R 840.4) by terms of validating the effective temperature concept and ways of acquiring it (chapter 6)

On Channel Modelling for Land Mobile Satellite Reception

In modernen Satellitenrundfunksystemen werden Methoden wie Zeitdiversität (Empfang von zeitlich verteilter Information) und Winkeldiversität (Empfang von mehreren Satelliten mit unterschiedlichen Positionen) angewandt, um die geforderte Dienstequalität für den mobilen Empfang zu gewährleisten. Zur Untersuchung der Ausbreitungseffekte des landmobilen Satellitenkanals sowohl der Wirksamkeit von Diversität werden statistische Modelle benötigt, die den zeitlichen Signalschwund des Empfangssignals nachbilden. In der vorliegenden Arbeit wird ein Kanalmodell für den Mehrsatellitenempfang entwickelt, welches genaue Versorgungsvorhersagen mit Zeit- und Winkeldiversität erlaubt.Grundlage ist ein Einsatellitenmodell, welches großräumige Schwankungen im Kanal durchdie Zustände ’gut’ und ’schlecht’ definiert, und den langsamen und schnellen Signalschwund gemäß einer variablen Loo-Verteilung beschreibt, deren Parameter nach jedem Zustandswechsel stochastisch bestimmt werden. Für die Zustandsmodellierung mit zwei Satelliten wird ein 'semi-Markov Modell für korrellierte Zustandssequenzen' erarbeitet. Damit können, unter Berücksichtigung der Statistiken der Einzelkanäle und deren Korrelationskoeffizient, die Zustandswahrscheinlichkeiten und-längen exakt simuliert werden. Für die Zustandsmodellierung mit drei Satelliten wird ein 'Master-Slave'-Ansatz entwickelt. Dabei sind die Zustandssequenzen zweier ’Slaves’ bedingt abhängig zur ’Master’-Sequenz. Der ’Master-Slave’-Ansatz ermöglicht die Parametrisierung eines Dreisatellitenmodells. Zur Beschreibung des langsamen und schnellen Signalschwunds im Mehrsatellitenkanal wirddie Wechselbeziehung zwischen synchron gemessenen Satellitensignalen näher untersucht.Es stellt sich heraus dass weitere Signalkorrelationen berücksichtigt werden sollten, dieerstmalig im neuen LMS-Kanalmodell implementiert werden. Die Simulationssergebnisse werden in Statistiken erster und zweiter Ordnung den Messdaten gegenübergestellt. Im Vergleich zu bestehenden Modellen werden Verbesserungen nach Berücksichtigung von Diversität deutlich. Die Parameter für das Mehrsatellitenkanalmodell wurden aus umfassenden Messkampagnen abgeleitet und gewährleisten die Signalsimulation für verschiedene Umgebungen und Satellitenpositionen. Abschließend wird das Kanalmodell für einen ersten Vergleich verschiedener Satellitenkonfigurationen mit Zeit- und Winkeldiversität angewandt.Modern digital satellite broadcasting systems combine time diversity (i.e. information is spread over a certain time interval) with angle diversity (i.e. information is received from multiple satellites in different orbital positions) to ensure uninterrupted service for mobile receivers over large areas. For assessing propagation effects of the land mobile satellite (LMS) channel and to study the efficacy of diversity, statistical models are required which generate time series of the received fading signal. In this thesis a narrowband LMS channel model for multi-satellite reception is developed focusing on accurate coverage prediction under consideration of angle- and time diversity. Basis is an existing single-satellite model, which describes large-scale signal variations of the channel by 'good' and 'bad' states, and models slow- and fast signal variations according to a versatile Loo distribution, which parameters are selected randomly when the channel enters a new state. For dual-satellite state modelling, a semi-Markov model for correlated state sequences is developed. It provides an accurate state probability and state duration modelling by considering the statistics of separate channels and their correlation coefficient. For the state modelling with three satellites, a new Master-Slave concept is introduced. Therefore, state sequences of slave satellites are conditioned by an existing master state sequence. The great advantage is that Master-Slave makes the parametrisation of a triple-satellite model feasible. To address slow- and fast variations for multi-satellite reception, the fading interdependence between synchronously received satellite signals is analysed from high-resolution measurement data. Hence additional correlations besides the state correlation are identified and firstly considered in the new multi-satellite LMS model. The modelling results are compared with the measurements in terms of first- and second order statistics, where improvements in describing diversity become visible when compared to existing models. Model parameters are derived from large-scale measurement campaigns to enable a time series generation for different environments and various constellations of satellites. The applicability of the new model is finally demonstrated by comparing the performance of different satellite constellations with diversity

On Channel Modelling for Land Mobile Satellite Reception

In modernen Satellitenrundfunksystemen werden Methoden wie Zeitdiversität (Empfang von zeitlich verteilter Information) und Winkeldiversität (Empfang von mehreren Satelliten mit unterschiedlichen Positionen) angewandt, um die geforderte Dienstequalität für den mobilen Empfang zu gewährleisten. Zur Untersuchung der Ausbreitungseffekte des landmobilen Satellitenkanals sowohl der Wirksamkeit von Diversität werden statistische Modelle benötigt, die den zeitlichen Signalschwund des Empfangssignals nachbilden. In der vorliegenden Arbeit wird ein Kanalmodell für den Mehrsatellitenempfang entwickelt, welches genaue Versorgungsvorhersagen mit Zeit- und Winkeldiversität erlaubt.Grundlage ist ein Einsatellitenmodell, welches großräumige Schwankungen im Kanal durchdie Zustände ’gut’ und ’schlecht’ definiert, und den langsamen und schnellen Signalschwund gemäß einer variablen Loo-Verteilung beschreibt, deren Parameter nach jedem Zustandswechsel stochastisch bestimmt werden. Für die Zustandsmodellierung mit zwei Satelliten wird ein 'semi-Markov Modell für korrellierte Zustandssequenzen' erarbeitet. Damit können, unter Berücksichtigung der Statistiken der Einzelkanäle und deren Korrelationskoeffizient, die Zustandswahrscheinlichkeiten und-längen exakt simuliert werden. Für die Zustandsmodellierung mit drei Satelliten wird ein 'Master-Slave'-Ansatz entwickelt. Dabei sind die Zustandssequenzen zweier ’Slaves’ bedingt abhängig zur ’Master’-Sequenz. Der ’Master-Slave’-Ansatz ermöglicht die Parametrisierung eines Dreisatellitenmodells. Zur Beschreibung des langsamen und schnellen Signalschwunds im Mehrsatellitenkanal wirddie Wechselbeziehung zwischen synchron gemessenen Satellitensignalen näher untersucht.Es stellt sich heraus dass weitere Signalkorrelationen berücksichtigt werden sollten, dieerstmalig im neuen LMS-Kanalmodell implementiert werden. Die Simulationssergebnisse werden in Statistiken erster und zweiter Ordnung den Messdaten gegenübergestellt. Im Vergleich zu bestehenden Modellen werden Verbesserungen nach Berücksichtigung von Diversität deutlich. Die Parameter für das Mehrsatellitenkanalmodell wurden aus umfassenden Messkampagnen abgeleitet und gewährleisten die Signalsimulation für verschiedene Umgebungen und Satellitenpositionen. Abschließend wird das Kanalmodell für einen ersten Vergleich verschiedener Satellitenkonfigurationen mit Zeit- und Winkeldiversität angewandt.Modern digital satellite broadcasting systems combine time diversity (i.e. information is spread over a certain time interval) with angle diversity (i.e. information is received from multiple satellites in different orbital positions) to ensure uninterrupted service for mobile receivers over large areas. For assessing propagation effects of the land mobile satellite (LMS) channel and to study the efficacy of diversity, statistical models are required which generate time series of the received fading signal. In this thesis a narrowband LMS channel model for multi-satellite reception is developed focusing on accurate coverage prediction under consideration of angle- and time diversity. Basis is an existing single-satellite model, which describes large-scale signal variations of the channel by 'good' and 'bad' states, and models slow- and fast signal variations according to a versatile Loo distribution, which parameters are selected randomly when the channel enters a new state. For dual-satellite state modelling, a semi-Markov model for correlated state sequences is developed. It provides an accurate state probability and state duration modelling by considering the statistics of separate channels and their correlation coefficient. For the state modelling with three satellites, a new Master-Slave concept is introduced. Therefore, state sequences of slave satellites are conditioned by an existing master state sequence. The great advantage is that Master-Slave makes the parametrisation of a triple-satellite model feasible. To address slow- and fast variations for multi-satellite reception, the fading interdependence between synchronously received satellite signals is analysed from high-resolution measurement data. Hence additional correlations besides the state correlation are identified and firstly considered in the new multi-satellite LMS model. The modelling results are compared with the measurements in terms of first- and second order statistics, where improvements in describing diversity become visible when compared to existing models. Model parameters are derived from large-scale measurement campaigns to enable a time series generation for different environments and various constellations of satellites. The applicability of the new model is finally demonstrated by comparing the performance of different satellite constellations with diversity

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Proceedings of the Twelfth NASA Propagation Experimenters Meeting (NAPEX 12)

The NASA Propagation Experimenters Meeting was convened on June 9 and 10, 1988. Pilot Field Experiments propagation studies, mobile communication systems, signal fading, communication satellites rain gauge network measurements, atmospheric attenuation studies, optical communication through the atmosphere, and digital beacon receivers were among the topics discussed