Broadband Island interconnection via satellite—performance analysis for the race II—catalyst project

The use of communication satellites as a possible way of offering broadband island interconnectivity appears to be a very attractive option, as it will enable the provision of an all-digital, transparent service to a number of ATM islands spanning a wide area, accommodating efficiently a variety of traffic demands. The CATALYST Project (RACE II/R2074) is an attempt to demonstrate the applicability and compatibility of satellite technology with the terrestrial BISDN. In this paper we present an overview of the project and focus on an initial study of the expected user performance through the CATALYST network. Our analysis is based upon mathematical and simulation models and describes the end-system to end-system transfer delay for given message lengths. The protocol profiles assume a mix of Novell NetWare and Network File System client/server architectures, which are supported by either the IEEE 802.3/Ethernet or fibre distributed data interface LANs, which are themselves linked via LAN/ATM/satellite interface units. Areas of further investigation, and the implication of our analysis on the actual network architecture, are discussed.     

Design and performance evaluation of a full-duplex operating receiver for time-hopping UWB

One of the most attractive features of time-hopping ultra-wide-band (UWB) transmission, largely ignored in the literature so far, is the possibility to operate in full-duplex mode, thanks to its very low duty-cycle. This allows a terminal to transmit and receive within the same time frame and frequency band, yielding a considerable saving of time and band resources at the radio-resource-management layer. In this paper, we propose a methodology to design channel estimation/synchronization and demodulation/decoding algorithms for a low-complexity receiver operating in full-duplex mode. The leading idea is simply to avoid, at reception, time intervals that correspond to pulse transmission. We also evaluate the performances of such a system through simulations over realistic propagation channels. Tomaso Erseghe was born in Valdagno, Italy, in 1972. He received the laurea degree and the PhD in Telecommunication Engineering from the University of Padova, Italy, respectively in 1996 and in 2002. From 1997 to 1999 he worked as an R&D Engineer at Snell & Wilcox, a British broadcast equipment manufacturer, in the areas of image restoration and motion compensation. From 2003 he is an Assistant Professor (Ricercatore) at the University of Padova. His research interests include fractional Fourier transforms, lossless encoding algorithms, and ultra-wideband transmission systems. Nicola Laurenti was born in 1970, in Adria, Italy. He graduated from the University of Padova with a laurea in Electrical Engineering in 1995, with a thesis on Image Reconstructions from Projections, and obtained a Ph.D. in Electrical and Telecommunications Engineering from the same University in February 1999, with a thesis on Implementation Issues in OFDM Systems. Since 2001 he is an Assistant Professor at the Department of Information Engineering, University of Padova. His research interests mainly focus on digital communications, especially multicarrier modulation and ultra wide band transmission, but also include signal theory, and the processing of audio and biomedical signals.     

阴影对GMSK卫星移动通信系统性能的影响

导出了采用L重最大比组合（MRC）和差分相位检测（DPD）方案的高斯最小频移键控（GMSK）卫星移动通信系统在不同信道条件下的误比特率公式，并利用实测数据给出数值计算结果。可用于分析阴影特性对卫星移动信道性能的影响并指导系统设计。     

A statistical model of FM-TV spectra for satellite interference and distortion prediction

The requirement for a model of FM-TV spectra in the planning procedure of satellite communication systems is introduced. Based on long-term measurements of live TV channels, statistical properties of video spectra are examined and probability distributions for the luminance and chrominance components are proposed. The spectrum of the frequency-modulated signal is then derived, and signal distortion due to bandlimiting is calculated. Adjacent and cochannel interference effects are also investigated, with example cases illustrating influences of subcarrier loading and energy dispersion. The proposed model, which describes FM-TV spectra in terms of random variables, makes it possible to examine relative effects of system parameters, and will, therefore, be of benefit in the planning of new satellite services.     

Statistical channel modelling and performance evaluation in satellite personal communications

This paper is concerned with channel modelling for satellite personal communications and with the associated problem of performance evaluation. Channel characteristics for personal communications tend to differ from those traditionally accepted for vehicular communications. In this paper we report on modelling aspects for both wideband and narrowband personal communications. Then we consider performance evaluation for low-altitude earth orbit (LEO) satellite systems in terms of bit error probability and outage probability. To evaluate the outage probability for LEO systems, a tight and simple upper bound is finally provided. © 1998 John Wiley & Sons, Ltd.     

Standardization on performance objectives of satellite systems using adaptive coding and modulation

The radiocommunication part of the International Telecommunication Union (ITU‐R) establishes the standards for wireless communications. Recommendation ITU‐R S.1062 specifies the performance objectives for satellite communication systems providing constant bit rate service. However, this is not applicable to most modern satellite communication systems utilizing adaptive coding and modulation (ACM) schemes to compensate for channel impairments, especially for systems operating in high frequency bands. For this reason, ITU‐R recently developed Recommendation ITU‐R S.2131 that is suitable for satellite systems with ACM. The developed Recommendation provides a method to determine performance objectives for satellite systems using ACM. Two possible objective parameters are presented, including packet error rate and spectral efficiency. This paper presents the standardization process, and the background used to establish new performance objectives. In addition, interpretations of the objectives are given by using estimation results for two different propagation characteristics.     

Ku-Band satellite data networks using very small aperture terminals—part II: System design

In this part of the paper on Ku-band VSAT networks, the issue of overall system design is considered. After discussing possible system architectures, primary attention is given to the star network configuration in which customer-premise VSATs communicate with a central hub station, co-located with, or terrestrially connected to a host computer. The component elements of a Ku-band star network for interactive data applications are discussed and the critical items from the point-of-view of performance, capacity and cost are identified. An analytical model for the network, which combines delay-throughput characterization of the multi-access inbound and TDM outbound channels with satellite link analysis is described. The analytical model is exercised over a range of typical system component, traffic model and performance objective scenarios to provide a set of general design guidelines. These guidelines are useful for evaluating the trade-offs between key system elements (channel access unit, modem, VSAT antenna and satellite), VSAT traffic message length parameters and the performance objectives (average and peak network response time and availability). The results are used to address the issue of multi-access protocol selection over a range of scenarios typical of 1.2 or 1.8m VSAT-based interactive networks using current commercial Ku-band satellites. The results show that interactive star networks are often limited by satellite power rather than bandwidth, so that the use of simple contention access for VSATs may not imply a significant system capacity penalty.     

Saw chirp filter technology for satellite on-board processing applications

Market growth in the area of thin route satellite communications services has led to consideration of non-traditional system architectures requiring sophisticated on-board processing functions. Surface acoustic wave (SAW) technology exists today which can provide implementation of key on-board processing subsystems by using multicarrier demodulators. This paper presents a review of this signal processing technology, along with a brief review of dispersive SAW device technology as applied to the implementation of multicarrier demodulators for on-board signal processing.     

An on-board processing satellite payload for european mobile communications

The paper considers the application of satellite on-board processing (OBP) technology for land mobile applications for possible introduction in the late 1990s. Initially a system outline is presented followed by a discussion considering the merits of OBP over conventional transparent payloads. The paper then presents an overview of the work being carried out as part of an ESA study. Some details on the critical parts of the system are also included.     

A frequency scanning satellite system for land mobile communications

A frequency scanning system for mobile applications has been assessed for a European mission at L-band. Feasibility evaluations, electrical design and analysis have been performed for both the antenna and the entire repeater. Efforts have also been made to solve accommodation, thermal and mechanical problems, so as to demonstrate the actual feasibility of the frequency scanning concept in user-oriented applications. The very promising results obtained are presented in this paper.     

AN ADAPTIVE FEC SCHEME FOR Ka-BAND SATELLITE COMMUNICATIONS

Rain attenuation is the major problem for Ka-band satellite communications, and the fading due to rain can be well described by a lognormally distributed, first-order autoregressive model. Forward Error-control Coding (FEC) techniques can be used to reduce the effect of the rain attenuation, but the use of FEC causes a reduction in the bandwidth efficiency. In order to increase the bandwidth efficiency as well as maintain high link availability, an Adaptive Forward Error-control Coding (AFEC) scheme with rain fading prediction is proposed and analyzed in this paper. The results show that AFEC offers a good trade-off between link availability and bandwidth efficiency.     

GMSK在跳频通信中的应用及其性能分析

本文将ＧＭＳＫ调制引入到跳频通信中,以利用ＧＭＳＫ高频谱效率的特点在跳频通信中实现高速数据传输。首先给出了采用ＧＭＳＫ调制的慢跳频通信系统ＳＦＨ－ＧＭＳＫ原理与实现方法,提出了基本的数学模型。在此基础上,获得了在不同的跳频间隔长度下ＳＦＨ－ＧＭＳＫ信号的频谱图。随后给出了基于Ｖｉｔｅｒｂｉ算法的ＳＦＨ－ＧＭＳＫ信号的非相干解调方案,并通过计算机模拟获得了该解调方案的误码性能。     

Efficient network coding techniques for time constrained multicast narrowband power line communications

Nowadays, power line communication (PLC) technology is receiving a renewed attention in many application fields. In particular, PLC is quite attractive for what concerns novel paradigms as smart microgrid systems and smart buildings. This paper deals with a proposal of a PLC scheme that efficiently allows multicast services based on the use of an efficient network coding (NC) scheme. Furthermore, an analytical approach is outlined to pursue the performance optimization of the proposed solution. Finally, the good behavior of the proposed NC approach is highlighted by presenting performance comparisons with the classical NC alternative.     

Rateless codes with adaptive parity allocation for satellite systems

In this paper, we propose efficient parity allocation schemes when rateless codes are used in satellite communication systems in conjunction with an adaptive coding and modulation (ACM) scheme. ACM schemes are widely used in modern satellite communication systems to maintain the required error rate performance under channel impairment (such as rain fading observed in high‐frequency bands). The performance enhancement of ACM can be achieved by providing a good channel prediction and mode allocation method. In the case of a channel prediction or allocation error, rateless codes can be used as an effective means of retransmission to compensate for the performance degradation. After investigating the performance behaviour of rateless codes combined with ACM, we derive a mathematical formula to find the optimum parity length of the rateless code to be retransmitted to satisfy the target performance requirements. Simulation results described in this paper show that the proposed method can be used to enhance the error performance as well as spectral efficiency.     

Development of a prototype,experimental single-channel sequencing navstar gps receiver: Part II—Software description

Late in 1988 the Navstar GPS satellite navigation operational phase is planned to commence, offering world-wide, continuous and precise position-fixing and timing information to observers on land, sea, air and in space. This paper describes the development of a particular type of Navstar receiver—a single-channel, single-frequency, sequencing C/A code unit—and results of various tests carried out on the present phase—II satellite constellation. Part I of this paper deals with the NAVSTAR satellite system and the development of receiver hardware, whereas Part II concentrates on software development and system performance.     

Development of a prototype,experimental single-channel sequencing navstar gps receiver: Part I—Hardware implementation

Late in 1988 the Navstar GPS satellite navigation operational phase is planned to commence, offering world-wide, continuous and precise position-fixing and timing information to observers on land, sea, air and in space. This paper describes the development of a particular type of Navstar receiver—a single-channel, single-frequency, sequencing C/A code unit—and results of various tests carried out on the present phase-II satellite constellation. Part I of the paper deals essentially with the NAVSTAR satellite system and receiver hardware implementation, whereas Part II concentrates on receiver software and system performance.     

Possible channel coding and modulation system for the satellite broadcasting of a high-definition television signal

A new coding/modulation approach is considered to improve service availability of digital high-definition television (HDTV) satellite broadcasting services at 22 GHz. This approach uses a concept of layered modulation in conjunction with layered picture coding and channel coding. By means of this technique, the service continuity can be extended without the needs for increasing the satellite transmission power, the service quality under severe atmospheric attenuations being reduced from high definition to normal definition.     

卫星导航接收端抗干扰性能测试平台构建方法

针对空间电磁环境的日益复杂化,卫星导航接收端抗干扰性能成为北斗用户密切关注的问题,为了测试动态导航接收端的抗干扰性能,提出一种室内无线抗干扰性能测试系统构建方法。采用基于灰色关联分析的场景映射方法、基于脚本的仪表驱动技术,结合信源模拟设备、微波开关、微波暗室等构建半实物仿真平台。不断调节干扰信号发射端输出功率,改变接收端有效载噪（C/N0）,据此获得导航接收端失锁时的输入信干比（J/S）。仿真结果表明:通过干信比与有效载噪比的关系曲线,实现对接收端的抗干扰性能测试,为卫星导航接收端抗干扰性能测试提供测试平台。     

An efficient protocol for providing integrated voice/data services to mobiles over power-limited satellite channels

Various mobile satellite communication systems are being developed for providing integrated voice/data services over a shared satellite transponder which is power-limited in nature. A common strategy is to use slotted ALOHA request channels to request channel assignments for voice/data calls from a network management station. To maximize efficiency in a system with a power-limited satellite transponder, it is proposed that the bursty nature of voice sources be exploited by the NMS to ‘over-assign’ channels. This may cause problems of inefficiency, potential instability as well as a degradation in the quality of service offered to the customers. Augmenting this with the introduction of simple state-dependent control procedures provides systems which exhibit more desirable operational features. This approach is proposed and examined in this paper.