Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 160
Book Description
The Telecommunications and Data Acquisition Progress Report 42-123
Author: Publications of the Jet Propulsion Laboratory, 1984
Author: Forward Error Correction Schemes for Data Communication Through Underwater Channel
Author: Dr. Raj Kumar GoswamiPublisher: Horizon Books ( A Division of Ignited Minds Edutech P Ltd)
ISBN: 9391150268
Category : Computers
Languages : en
Pages : 147
Book Description
The primary endeavor of this book is to provide an insight to the Forward Error Correction schemes so as to transfer the extracted features of the detected objects along with any intended data in a reliable manner through underwater channel. The main challenge with respect to the development of the coding techniques is the phenomena governing the propagation of signals through the underwater channel. It offers the biggest challenge imposing severe limitations on the effective throughput of transmission. The major problems encountered in the underwater channel are related to time-varying ISI and frequency-selective fading. An extensive literature review has also been presented with respect to Error Correction Coding schemes. This survey provided the necessary base for formulating the design alternatives. These alternatives attempted to exploit the recent advances in the error correction coding techniques, for data communication through underwater channel. Factors like design and implementation complexity of error correction schemes and the amount of overheads involved in transmission have also been considered in the critical assessment of these alternatives. An overview of the Sonar theory has also been presented along with the brief introduction of the forward-looking Sonars. The types of Forward-Looking Sonars have also been discussed in very brief. A comparison of the general parameters of the terrestrial and underwater systems is also carried out along with the variations in the path loss offered by the two systems with frequency and distance. The characteristics of propagation in the underwater medium are also elaborated. Underwater Channel modeling is also introduced in the book along with a study of the Rician and Rayleigh models which characterize the fading environment. The Rician and Rayleigh distributions are compared in terms of their application to real world scenarios. In the real underwater scenario, there is also a direct path along with the diffused/ indirect paths. Therefore, the most suitable model that can be used for testing the designed coding schemes is the Rician Fading model (K-factor = 2) along with the Additive White Gaussian Noise. The various Forward Error Correction Schemes have been discussed for the purpose of achieving reliable transmission of the formulated data block. The designs of the two Convolutional coding schemes i.e. rate 1/n and rate n/(n+1) have also been presented. It is observed from the comparison of Convolutional and TCM coding schemes that improvement in the performance of either code can be obtained with increase in the coding rate. The Turbo Codes have also been introduced and it will be seen that the performance of turbo code is sensitive to its code structure. The problem of the application of turbo codes to underwater communication systems has also been addressed. The main disadvantage of the Turbo codes is their long latency due to their relatively large codewords and iterative decoding process. However, the Turbo codes score over the Convolutional and the TCM codes in that they can be made sufficiently random to achieve a given BER and by using iterative methods, can be efficiently and feasibly decoded. The designed coding algorithm has been incorporated into the various configurations of the Turbo coding scheme. The variation in the configurations is in the coding rate and the number of states. The interleaver used in the design has been chosen as the random interleaver. The Turbo Coding Schemes have been designed by implementing the Convolutional coders as the constituent encoders using the proposed design rules. The design has been carried out for the 1/n and the n/(n+1) code rates with various states. The performance analysis of the proposed turbo schemes is also presented in terms of the Bit Error Rate (BER) achieved.
Antenna Arraying Techniques in the Deep Space Network
Author: David H. RogstadPublisher: John Wiley & Sons
ISBN: 0471721301
Category : Technology & Engineering
Languages : en
Pages : 184
Book Description
An introduction to antenna Arraying in the Deep Space network Antenna arraying is the combining of the output from several antennas in order to improve the signal-to-noise ratio (SNR) of the received signal. Now implemented at the Goldstone Complex and other Deep Space Network (DSN) overseas facilities, antenna arraying provides flexible use of multiple antennas to increase data rates and has enabled NASA's DSN to extend the missions of some spacecraft beyond their planned lifetimes. Antenna Arraying Techniques in the Deep Space Network introduces the development and use of antenna arraying as it is implemented in the DSN. Drawing on the work of scientists at JPL, this timely volume summarizes the development of antenna arraying and its historical background; describes key concepts and techniques; analyzes and compares several methods of arraying; discusses several correlation techniques used for obtaining the combined weights; presents the results of several arraying experiments; and suggests directions for future work. An important contribution to the scientific literature, Antenna Arraying Techniques in the Deep Space Network * Was commissioned by the JPL Deep Space Communications and Navigation Systems (DESCANSO) Center of Excellence * Highlights many NASA-funded technical contributions pertaining to deep space communications systems * Is a part of the prestigious JPL Deep Space Communications and Navigation Series The Deep Space Communications and Navigation Series is authored by scientists and engineers with extensive experience in astronautics, communications, and related fields. It lays the foundation for innovation in the areas of deep space navigation and communications by disseminating state-of-the-art knowledge in key technologies.
The Telecommunications and Data Acquisition Progress Report 42-123
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781723452956
Category :
Languages : en
Pages : 154
Book Description
The progress of research programs monitored by the Jet Propulsion Laboratory's Telecommunications and Mission Operations Directorate (TMOD) are presented in this quarterly document. Areas monitored include space communications, radio navigation, radio science, ground-based radio and radar astronomy, information systems, and all other communication and research technology activities for the Deep Space Network (DSN). Yuen, Joseph H. (Editor) Jet Propulsion Laboratory DEEP SPACE NETWORK; EARTH ORIENTATION; GLOBAL POSITIONING SYSTEM; INFORMATION SYSTEMS; INTERPLANETARY NAVIGATION; MICROWAVE OSCILLATORS; RADAR ASTRONOMY; RADIO ASTRONOMY; RADIO NAVIGATION; SPACE COMMUNICATION; SPACECRAFT COMMUNICATION; SPACECRAFT CONTROL; CIRCULAR POLARIZATION; COMPUTER AIDED DESIGN; COMPUTER PROGRAMMING; DATA ACQUISITION; ERROR CORRECTING CODES; GUSTS; MATHEMATICAL MODELS; NOISE TEMPERATURE; SIGNAL DETECTION; SINE WAVES; TRELLIS CODING; WIND MEASUREMENT; YAW...
The Telecommunications and Data Acquisition Report
Author: Proceedings of the Fifth International Mobile Satellite Conference 1997, IMSC '97
Author: Louise AndersonPublisher:
ISBN:
Category : Artificial satellites in telecommunication
Languages : en
Pages : 594
Book Description
The Telecommunications and Data Acquisition Progress Report
Author: Advanced Multimedia and Ubiquitous Engineering
Author: James J. (Jong Hyuk) ParkPublisher: Springer
ISBN: 9811015368
Category : Computers
Languages : en
Pages : 789
Book Description
This volume presents selected papers from prominent researchers participating in the 11th International Conference on Future Information Technology and the 10th International Conference on Multimedia and Ubiquitous Engineering, Beijing, China, April 20-22, 2016. These large international conferences provided an opportunity for academic and industry professionals to discuss recent progress in the fields of multimedia technology and ubiquitous engineering including new models and systems and novel applications associated with the utilization and acceptance of ubiquitous computing devices and systems. The contributions contained in this book also provide more information about digital and multimedia convergence, intelligent applications, embedded systems, mobile and wireless communications, bio-inspired computing, grid and cloud computing, the semantic web, user experience and HCI, security and trust computing. This book describes the state of the art in multimedia and ubiquitous engineering, and future IT models and their applications.
Deep Space Optical Communications
Author: Hamid HemmatiPublisher: John Wiley & Sons
ISBN: 0470042400
Category : Technology & Engineering
Languages : en
Pages : 683
Book Description
A quarter century of research into deep space and near Earth optical communications This book captures a quarter century of research and development in deep space optical communications from the Jet Propulsion Laboratory (JPL). Additionally, it presents findings from other optical communications research groups from around the world for a full perspective. Readers are brought up to date with the latest developments in optical communications technology, as well as the state of the art in component and subsystem technologies, fundamental limitations, and approaches to develop and fully exploit new technologies. The book explores the unique requirements and technologies for deep space optical communications, including: * Technology overview; link and system design drivers * Atmospheric transmission, propagation, and reception issues * Flight and ground terminal architecture and subsystems * Future prospects and applications, including navigational tracking and light science This is the first book to specifically address deep space optical communications. With an increasing demand for data from planetary spacecraft and other sources, it is essential reading for all optical communications, telecommunications, and system engineers, as well as technical managers in the aerospace industry. It is also recommended for graduate students interested in deep space communications.