Low-complexity Iterative Receiver Algorithms for Multiple-input Multiple-output Underwater Wireless Communications PDF Download

Author: Weimin Duan
Publisher:
ISBN:
Category : Feedback control systems
Languages : en
Pages : 119

View

Book Description
"This dissertation proposes three low-complexity iterative receiver algorithms for multiple-input multiple-output (MIMO) underwater acoustic (UWA) communications. First is a bidirectional soft-decision feedback Turbo equalizer (Bi-SDFE) which harvests the time-reverse diversity in severe multipath MIMO channels. The Bi-SDFE outperforms the original soft-decision feedback Turbo equalizer (SDFE) while keeping its total computational complexity similar to that of the SDFE. Second, this dissertation proposes an efficient direct adaptation Turbo equalizer for MIMO UWA communications. Benefiting from the usage of soft-decision reference symbols for parameter adaptation as well as the iterative processing inside the adaptive equalizer, the proposed algorithm is efficient in four aspects: robust performance in tough channels, high spectral efficiency with short training overhead, time efficient with fast convergence and low complexity in hardware implementation. Third, a frequency-domain soft-decision block iterative equalizer combined with iterative channel estimation is proposed for the uncoded single carrier MIMO systems with high data efficiency. All the three new algorithms are evaluated by data recorded in real world ocean experiment or pool experiment. Finally, this dissertation also compares several Turbo equalizers in single-input single-output (SISO) UWA channels. Experimental results show that the channel estimation based Turbo equalizers are robust in SISO underwater transmission under harsh channel conditions"--Abstract, page iv.

Author: Jun Won Choi
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
In this dissertation, efficient receiver algorithms and architectures for digital communications are studied. As the demand for higher data communication rate increases, the dimension of communication systems is rapidly growing, thereby requiring computationally efficient detection and decoding algorithms in the receiver. Hence, it is crucial to develop receiver algorithms that can offer good performance-complexity trade-offs in high dimensional communication systems such as multi-input multi-output (MIMO) systems and systems with a large delay spread. In this dissertation, computationally efficient receiver algorithms and low-power implementation of receiver architectures are investigated. First, a low-complexity near maximum-likelihood (ML) detector, called the reduced-dimension ML search (RD-MLS), is proposed. The main idea of the RD-MLS is based on reduction of search space dimension. That is, a solution is searched over a subset of symbols to reduce the search complexity. In order to minimize the inevitable performance loss due to the search space reduction, a list tree search (LTS) algorithm is employed, which finds the best K candidates over the reduced search space. A final solution is chosen among the K candidates after extension to the full dimension via an MMSE decision-feedback (MMSE-DF) detector. To determine the candidate size, K adaptively, a stopping criterion is incorporated into the LTS. Through computer simulations, we demonstrate that the RD-MLS algorithm achieves significant complexity reduction over the existing near ML detectors while limiting performance loss to within one dB from ML detection. Second, a low complexity MIMO tree detector, called the improved soft-input soft-output M-algorithm (ISS-MA), is presented. The proposed detector is developed for iterative detection and decoding (IDD) systems, which are known to achieve near-optimal detection performance for MIMO channels. In order to improve the performance of tree detection, a look-ahead path metric is employed that accounts for the impact of unvisited paths of the tree via an unconstrained linear MMSE estimator. Based on an analysis of the probability of correct path loss, we show that the improved path metric offers better detection performance than the conventional path metric. We also demonstrate through simulations that the ISS-MA provides a better performance-complexity trade-off than existing soft-input soft-output detection algorithms. Third, a computationally efficient turbo equalization algorithm for underwater acoustic communications is studied. The performances of two popular linear turbo equalizers, a channel estimate-based minimum mean square error TEQ (CE-based MMSE-TEQ) and a direct-adaptive TEQ (DA-TEQ) technique, are compared in the presence of channel estimation errors and adjustment errors of a least mean square (LMS) adaptive algorithm. Next, an underwater receiver architecture built upon the LMS DA-TEQ technique is introduced. To maintain a performance gains over time-varying channels, the convergence speed of the LMS algorithm is improved via two methods: (1) data reusing and gear-shifting LMS and (2) reducing the length of the equalizer by capturing the sparse structure of underwater acoustic channels. In addition, the sparse structure resulting from the underwater channel can be exploited to reduce the complexity of the equalizer and mitigate error propagation. Receiver performance for different modulation orders, channel codes, and hydrophone configurations was examined at a variety of distances, up to 1 km, from the transmitters. Experimental results show great promise for this approach, as data rates in excess of 15 kbit/s could readily be achieved without error. Lastly, an energy efficient estimation and detection problem is formulated for low-power digital filtering. Building on the soft digital signal processing technique that combines algorithmic noise tolerance and voltage scaling to reduce power, a minimum power soft error cancellation (MP-SEC) technique detects, estimates and corrects transient errors that arise from voltage over-scaling. These timing violation-induced errors, called soft errors, can be detected and corrected by exploiting the correlation structure induced by the filtering operation being protected, together with a reduced-precision replica of the protected operation. By exploiting a spacing property of soft errors in certain architectures, MP-SEC can achieve up to 30 % power savings with no SNR loss and up to 55 % power savings with less than 1 dB SNR loss, according to logic-level simulations performed for an example 25-tap frequency-selective filter.

Author: Paul C. Etter
Publisher: CRC Press
ISBN: 1351679724
Category : Technology & Engineering
Languages : en
Pages : 639

View

Book Description
This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally

Author: Sheng Zhou
Publisher: John Wiley & Sons
ISBN: 1118693817
Category : Science
Languages : en
Pages : 498

View

Book Description
A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver design in systems with single or multiple transmitters. This is the main body of the book. Extensive experimental data sets are used to verify the receiver performance. In the third part, the authors discuss applications of the OFDM receiver in i) deep water channels, which may contain very long separated multipath clusters, ii) interference-rich environments, where an unintentional interference such as Sonar will be present, and iii) a network with multiple users where both non-cooperative and cooperative underwater communications are developed. Lastly, it describes the development of a positioning system with OFDM waveforms, and the progress on the OFDM modem development. Closely related industries include the development and manufacturing of autonomous underwater vehicles (AUVs) and scientific sensory equipment. AUVs and sensors in the future could integrate modems, based on the OFDM technology described in this book. Contents includes: Underwater acoustic channel characteristics/OFDM basics/Peak-to-average-ratio control/Detection and Doppler estimation (Doppler scale and CFO)/Channel estimation and noise estimation/A block-by-block progressive receiver and performance results/Extensions to multi-input multi-output OFDM/Receiver designs for multiple users/Cooperative underwater OFDM (Physical layer network coding and dynamic coded cooperation)/Localization with OFDM waveforms/Modem developments A valuable resource for Graduate and postgraduate students on electrical engineering or physics courses; electrical engineers, underwater acousticians, communications engineers

Author: Paul C. Etter
Publisher: CRC Press
ISBN: 1351679716
Category : Technology & Engineering
Languages : en
Pages : 776

View

Book Description
This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally, the text discusses new applications including underwater acoustic networks and channel models, marine-hydrokinetic energy devices, and simulation of anthropogenic sound sources. It further includes instructive case studies to demonstrate applications in sonar simulation.

Author: Ming Yue
Publisher:
ISBN:
Category : Oceanographic instruments
Languages : en
Pages : 41

View

Book Description
"This thesis designs a low-complexity dual Pseudorandom Noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences for a node are identical and are separated by a specified length of gap which serves as the ID of different sensor nodes. The dual PN sequences are short in length but are capable of combating severe underwater acoustic (UWA) multipath fading channels that exhibit time varying impulse responses up to 100 taps. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the PN sequence with the specified separation gap. When the gap length is matched, the correlator outputs a peak which triggers the wake-up enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. The correlator is implemented by an iterative algorithm that uses only one multiplication and two additions for each sample input regardless of the length of the PN sequence, thus achieving low computational complexity. The real-time processing requirement is also met via direct memory access (DMA) and two circular buffers to accelerate data transfer between the peripherals and the memory. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver. The future research will integrate the wake-up receiver with Digital Signal Processors (DSP) for payload detection."--Abstract, page iv.

Author: Ivan A. Parinov
Publisher: Springer Nature
ISBN: 3030764818
Category : Technology & Engineering
Languages : en
Pages : 601

View

Book Description
This book presents selected peer-reviewed contributions from the 2020 International Conference on “Physics and Mechanics of New Materials and Their Applications”, PHENMA 2020 (26–29 March 2021, Kitakyushu, Japan), focusing on processing techniques, physics, mechanics, and applications of advanced materials. The book describes a broad spectrum of promising nanostructures, crystal structures, materials, and composites with unique properties. It presents nanotechnological design approaches, environmental-friendly processing techniques, and physicochemical as well as mechanical studies of advanced materials. The selected contributions describe recent progress in computational materials science methods and algorithms (in particular, finite-element and finite-difference modelling) applied to various technological, mechanical, and physical problems. The presented results are important for ongoing efforts concerning the theory, modelling, and testing of advanced materials. Other results are devoted to promising devices with higher accuracy, increased longevity, and greater potential to work effectively under critical temperatures, high pressure, and in aggressive environments.

Author: Zhaocheng Wang
Publisher: John Wiley & Sons
ISBN: 1119331382
Category : Technology & Engineering
Languages : en
Pages : 368

View

Book Description
A complete and comprehensive reference on modulation and signal processing for visible light communication This informative new book on state-of-the-art visible light communication (VLC) provides, for the first time, a systematical and advanced treatment of modulation and signal processing for VLC. Visible Light Communications: Modulation and Signal Processing offers a practical guide to designing VLC, linking academic research with commercial applications. In recent years, VLC has attracted attention from academia and industry since it has many advantages over the traditional radio frequency, including wide unregulated bandwidth, high security, and low cost. It is a promising complementary technique in 5G and beyond wireless communications, especially in indoor applications. However, lighting constraints have not been fully considered in the open literature when considering VLC system design, and its importance has been underestimated. That’s why this book—written by a team of experts with both academic research experience and industrial development experience in the field—is so welcome. To help readers understand the theory and design of VLC systems, the book: Details many modern techniques on both modulation and signal processing aspects Links academic research with commercial applications in visible light communications as well as other wireless communication systems Combines theoretical rigor with practical examples in presenting optical camera communication systems Visible Light Communications: Modulation and Signal Processing serves as a useful tool and reference book for visible light communication professionals, as well as wireless communication system professionals and project managers. It is also an important guide for undergraduates and graduates who want to conduct research in areas of wireless communications.

Author: Franz Hlawatsch
Publisher: Academic Press
ISBN: 0080922724
Category : Technology & Engineering
Languages : en
Pages : 457

View

Book Description
As a result of higher frequencies and increased user mobility, researchers and systems designers are shifting their focus from time-invariant models to channels that vary within a block. Wireless Communications Over Rapidly Time-Varying Channels explains the latest theoretical advances and practical methods to give an understanding of rapidly time varying channels, together with performance trade-offs and potential performance gains, providing the expertise to develop future wireless systems technology. As well as an overview of the issues of developing wireless systems using time-varying channels, the book gives extensive coverage to methods for estimating and equalizing rapidly time-varying channels, including a discussion of training data optimization, as well as providing models and transceiver methods for time-varying ultra-wideband channels. An introduction to time-varying channel models gives in a nutshell the important issues of developing wireless systems technology using time-varying channels Extensive coverage of methods for estimating and equalizing rapidly time-varying channels, including a discussion of training data optimization, enables development of high performance wireless systems Chapters on transceiver design for OFDM and receiver algorithms for MIMO communication channels over time-varying channels, with an emphasis on modern iterative turbo-style architectures, demonstrates how these important technologies can optimize future wireless systems

Author: Tolga M. Duman
Publisher: John Wiley & Sons
ISBN: 9780470724330
Category : Technology & Engineering
Languages : en
Pages : 366

View

Book Description
Coding for MIMO Communication Systems is a comprehensive introduction and overview to the various emerging coding techniques developed for MIMO communication systems. The basics of wireless communications and fundamental issues of MIMO channel capacity are introduced and the space-time block and trellis coding techniques are covered in detail. Other signaling schemes for MIMO channels are also considered, including spatial multiplexing, concatenated coding and iterative decoding for MIMO systems, and space-time coding for non-coherent MIMO channels. Practical issues including channel correlation, channel estimation and antenna selection are also explored, with problems at the end of each chapter to clarify many important topics. A comprehensive book on coding for MIMO techniques covering main strategies Theories and practical issues on MIMO communications are examined in detail Easy to follow and accessible for both beginners and experienced practitioners in the field References at the end of each chapter for further reading Can be used with ease as a research book, or a textbook on a graduate or advanced undergraduate level course This book is aimed at advanced undergraduate and postgraduate students, researchers and practitioners in industry, as well as individuals working for government, military, science and technology institutions who would like to learn more about coding for MIMO communication systems.