Frame Synchronization In Ofdm Systems

In this thesis, we considered the problem of frame synchronization and channel estimation in Orthogonal Frequency Division Multiplexing (OFDM) systems. Since framing error may cause severe ISI and may disturb the orthogonality of the subcarriers, frame synchronization must be accomplished at the OFDM receiver. Furthermore, the effects of channel must be compensated to obtain the symbols accurately. We investigated several frame synchronization algorithms including a maximum likelihood (ML) synchronizer which relies on the periodicity induced in the OFDM structure, and a robust synchronizer which uses a special training symbol. These algorithms are evaluated in AWGN and Rayleigh fading multipath channels and performances are compared in terms of percentage of ISI-free synchronization, mean squared error and symbol error rate. The IEEE 802.11a framework is used to compare these algorithms with the standard system which utilizes training symbols dedicated for synchronization. It is shown that an adjustment for the frame start estimates must be done to avoid the effects of the channel delay spread. It is also pointed that ideal synchronization is not necessary unless symbol boundaries are detected inside an ISI-free region and the error aroused in ISI-free synchronization can be compensated by applying channel estimation and equalization regarding the same symbol boundaries.

From the reviews: "This book [...] gives a comprehensive overview of the implementation of OFDM systems. [...] For those who study or work on broadband communication in a wireless multipath environment, this book is a useful and easy-to-read reference. [...]" (Zongsen Wu, Shaowen Song and Tianying Ji, Physics and Computing Dept., Wilfrid Laurier University, ON)

Orthogonal Frequency Division Multiplexing (OFDM) systems are widely used in the standards for digital audio/video broadcasting, WiFi and WiMax. Being a frequency-domain approach to communications, OFDM has important advantages in dealing with the frequency-selective nature of high data rate wireless communication channels. As the needs for operating with higher data rates become more pressing, OFDM systems have emerged as an effective physical-layer solution. This short monograph is intended as a tutorial which highlights the deleterious aspects of the wireless channel and presents why OFDM is a good choice as a modulation that can transmit at high data rates. The system-level approach we shall pursue will also point out the disadvantages of OFDM systems especially in the context of peak to average ratio, and carrier frequency synchronization. Finally, simulation of OFDM systems will be given due prominence. Simple MATLAB programs are provided for bit error rate simulation using a discrete-time OFDM representation. Software is also provided to simulate the effects of inter-block-interference, inter-carrier-interference and signal clipping on the error rate performance. Different components of the OFDM system are described, and detailed implementation notes are provided for the programs. The program can be downloaded here. Table of Contents: Introduction / Modeling Wireless Channels / Baseband OFDM System / Carrier Frequency Offset / Peak to Average Power Ratio / Simulation of the Performance of OFDM Systems / Conclusions

Orthogonal frequency-division multiplexing (OFDM) access schemes are becoming more prevalent among cellular and wireless broadband systems, accelerating the need for smaller, more energy efficient receiver solutions. Up to now the majority of OFDM texts have dealt with signal processing aspects. To address the current gap in OFDM integrated circuit (IC) instruction, Chiueh and Tsai have produced this timely text on baseband design. OFDM Baseband Receiver Design for Wireless Communications covers the gamut of OFDM technology, from theories and algorithms to architectures and circuits. Chiueh and Tsai give a concise yet comprehensive look at digital communications fundamentals before explaining modulation and signal processing algorithms in OFDM receivers. Moreover, the authors give detailed treatment of hardware issues -- from design methodology to physical IC implementation. Closes the gap between OFDM theory and implementation Enables the reader to transfer communication receiver concepts into hardware design wireless receivers with acceptable implementation loss achieve low-power designs Contains numerous figures to illustrate techniques Features concrete design examples of MC-CDMA systems and cognitive radio applications Presents theoretical discussions that focus on concepts rather than mathematical derivation Provides a much-needed single source of material from numerous papers Based on course materials for a class in digital communication IC design, this book is ideal for advanced undergraduate or post-graduate students from either VLSI design or signal processing backgrounds. New and experienced engineers in industry working on algorithms or hardware for wireless communications devices will also find this book to be a key reference.

This practical guide helps readers to learn how to develop and implement synchronization functions in digital communication systems.

Wireless networking technologies are witnessed to become the integral part of industry, business, entertainment and daily life. Encyclopedia of Wireless Networks is expected to provide comprehensive references to key concepts of wireless networks, including research results of historical significance, areas of current interests, and growing directions in the future wireless networks. It can serve as a valuable and authoritative literature for students, researchers, engineers, and practitioners who need a quick reference to the subjects of wireless network technology and its relevant applications. Areas covered: 5G Network | Editors: Rahim Tafazolli, Rose Hu Ad hoc Network | Editor: Cheng Li Big Data for Networking | Editor: Song Guo Cellular Network, 2G/3G Network, 4G/LTE Network | Editor: Hsiao-hwa Chen Cognitive Radio Network | Editor: Ning Zhang Cooperative Communications | Editor: Kaoru Ota Cyber Physical Systems | Editor: Shiyan Hu Data Center Network | Editor: Lei Lei Delay Tolerant and Opportunistic Network | Editor: Yuanguo Bi Equalization, Synchronization and Channel Estimation | Editor: Yingying Chen Future Network Architecture | Editor: Wei Quan Game Theory in Wireless Network | Editor: Dusit Niyato Interference Characterization and Mitigation | Editor: Lin Cai Internet of Things | Editors: Xiuzhen Cheng, Wei Cheng Internet of Things and its Applications | Editor: Phone Lin Interworking Heterogeneous Wireless Network | Editor: Ping Wang Medium Access Control | Editors: Hassan Omar, Qiang Ye Millimeter-wave Communications | Editor: Ming Xiao MIMO-based Network | Editor: Prof. Wei Zhang Mobility Management and Models | Editors: Sandra Cespedes, Sangheon Pack Molecular, Biological and Multi-scale Communications | Editor: Adam Noel Network Economics and pricing | Editors: Jianwei Huang, Yuan Luo Network Forensics and surveillance, Fault Tolerance and Reliability | Editor: Hongwei Li Network Measurement and Virtualization | Editor: Yusheng Ji Quality of Service, Quality of Experience and Quality of Protection | Editors: Rui Luis Aguiar, Yu Cheng Resource Allocation and Management | Editors: Junshan Zhang, Nan Cheng Routing and Multi-cast, Router and Switch Design | Editor: Richard Yu Scaling Laws and Fundamental Limits | Editor: Ning Lu Security, Privacy and Trust | Editor: Kui Ren Short Range Communications, RFID and NFC | Editor: Zhiguo Shi Smart Grid Communications | Editor: Vincent W. S. Wong Vehicular Network | Editors: Lian Zhao, Qing Yang Video Streaming | Editor: Zhi Liu Wireless Body Area Network and e-healthcare | Editor: Honggang Wang Wireless Security | Editors: Haojin Zhu, Jian Shen Wireless Sensor Network | Editors: Jiming Chen, Ruilong Deng WLAN and OFDM | Editor: Xianbin Wang

The Second Edition of OFDM Baseband Receiver Design for Wirless Communications, this book expands on the earlier edition with enhanced coverage of MIMO techniques, additional baseband algorithms, and more IC design examples. The authors cover the full range of OFDM technology, from theories and algorithms to architectures and circuits. The book gives a concise yet comprehensive look at digital communication fundamentals before explaining signal processing algorithms in receivers. The authors give detailed treatment of hardware issues - from architecture to IC implementation. Links OFDM and MIMO theory with hardware implementation Enables the reader to transfer communication received concepts into hardware; design wireless receivers with acceptable implemntation loss; achieve low-power designs Covers the latest standards, such as DVB-T2, WiMax, LTE and LTE-A Includes more baseband algorithms, like soft-decoding algorithms such as BCJR and SOVA Expanded treatment of channel models, detection algorithms and MIMO techniques Features concrete design examples of WiMAX systems and cognitive radio apllications Companion website with lecture slides for instructors Based on materials developed for a course in digital communication IC design, this book is ideal for graduate students and researchers in VLSI design, wireless communications, and communications signal processing. Practicing engineers working on algorithms or hardware for wireless communications devices will also find this to be a key reference.