Error Control Techniques for Satellite and Space Communications


Book Description

Brief summaries of research in the following areas are presented: (1) construction of optimum geometrically uniform trellis codes; (2) a statistical approach to constructing convolutional code generators; and (3) calculating the exact performance of a convolutional code. Costello, Daniel J., Jr. Unspecified Center NASA-CR-196302, NAS 1.26:196302 NAG5-557...




Handbook on Satellite Communications


Book Description

An essential overview of satellite communications from the organization that sets the international standards Since their introduction in the mid-1960s, satellite communications have grown from a futuristic experiment into an integral part of today's "wired world." Satellite communications are at the core of a global, automatically switched telephony network. Assembled by the International Telecommunication Union--the international organization that sets the standards for this rapidly growing industry--the Handbook on Satellite Communications, Third Edition brings together basic facts about satellite communications as related to the fixed-satellite service (FSS). It covers the main principles, technologies, and operation of equipment in a tutorial form. Updated to include the latest technologies and information, the Third Edition provides both the standards and technical information needed to implement and interact with satellite communication systems, including: * The components and basic characteristics of a satellite communication system * Regulatory considerations and system planning * SDH and ATM satellite transmissions * Analog and digital baseband signal processing and multiplexing * Carrier modulation techniques * Geostationary and non-geostationary systems * Interconnection of satellite and terrestrial networks * LEOS satellite networks and other recent developments As digital modulation and transmission replace analog techniques, and as satellites in non-geostationary and lower-altitude orbits open the way to new applications, satellite communications will continue to grow in use and importance. Everyone involved in the administration and operation of satellite communications will find this a crucial resource.




Satellite Communications


Book Description




Adaptive Error Correcting Techniques for Use in Airborne Satellite Communications Systems


Book Description

Airborne satellite communication systems have been shown to frequently suffer severe degradation of performance due to ionospheric scintillation. This type of interference produces deep fades in received signal power resulting in long error bursts in the demodulated data stream. The objective of this study was to lay the groundwork for a quantitative evaluation of the performance improvement that can be achieved through the use of an adaptive error control technique. Specifically, the adaptive Gallager algorithm and the extended Gallager algorithm were examined to determine which of these provides the better solution ot the error control problem on this channel. The first phase of this study dealt with the heuristic analysis of these two error control techniques on the basis of binary error sequences generated from flight test records of received signal level. Phase I culminates with a recommendation as to which technique should be used. Suggestions regarding the values of important algorithm parameters are also provided. Phase II of this study was devoted to the development of a computer simulation algorithm and the design of a hardware evaluator for the recommended coding technique. The algorithm, used with the AFAL channel simulator, permits the quantitative evaluation of code performance on the simulated scintillation channel.










Satellite Communications


Book Description

Extensive revision of the best-selling text on satellite communications — includes new chapters on cubesats, NGSO satellite systems, and Internet access by satellite There have been many changes in the thirty three years since the first edition of Satellite Communications was published. There has been a complete transition from analog to digital communication systems, withanalog techniques replaced by digital modulation and digital signal processing. While distribution of television programming remains the largest sector of commercial satellite communications, low earth orbit constellations of satellites for Internet access are set to challenge that dominance. In the third edition, chapters one through three cover topics that are specific to satellites, including orbits, launchers, and spacecraft. Chapters four through seven cover the principles of digital communication systems, radio frequency communications, digital modulation and multiple access techniques, and propagation in the earth’s atmosphere, topics that are common to all radio communication systems. Chapters eight through twelve cover applications that include non-geostationary satellite systems, low throughput systems, direct broadcast satellite television, Internet access by satellite, and global navigation satellite systems. The chapter on Internet access by satellite is new to the third edition, and each of the chapters has been extensively revised to include the many changes in the field since the publication of the second edition in 2003. Two appendices have been added that cover digital transmission of analog signals, and antennas. An invaluable resource for students and professionals alike, this book: Focuses on the fundamental theory of satellite communications Explains the underlying principles and essential mathematics required to understand the physics and engineering of satellite communications Discusses the expansion of satellite communication systems in areas such as direct-broadcast satellite TV, GPS, and internet access Introduces the rapidly advancing field of small satellites, referred to as SmallSats or CubeSats Provides relevant practice problems based on real-world satellite systems Satellite Communications is required reading for undergraduate and postgraduate students in satellite communications courses and an authoritative reference for engineers working in communications, systems and networks, and satellite operations and management.




Error Control Coding Techniques for Space and Satellite Communications


Book Description

It is well known that the BER performance of a parallel concatenated turbo-code improves roughly as 1/N, where N is the information block length. However, it has been observed by Benedetto and Montorsi that for most parallel concatenated turbo-codes, the FER performance does not improve monotonically with N. In this report, we study the FER of turbo-codes, and the effects of their concatenation with an outer code. Two methods of concatenation are investigated: across several frames and within each frame. Some asymmetric codes are shown to have excellent FER performance with an information block length of 16384. We also show that the proposed outer coding schemes can improve the BER performance as well by eliminating pathological frames generated by the iterative MAP decoding process. Costello, Daniel J., Jr. and Takeshita, Oscar Y. and Cabral, Hermano A. Goddard Space Flight Center NAG5-557...