This thesis discusses different channel estimation techniques, channel equalization and various diversity schemes for broadband wireless communication employing single-carrier frequency domain equalization. With the help of simulation results, we have compared the performance of SC-FDE system employing three different channel estimation techniques namely Least Mean Square based channel estimation for adaptive frequency-domain equalization, Unique Word based channel estimation and interpolation based channel estimation. The simulations are run for various values of Doppler spreads. MMSE based frequency-domain equalizer is used throughout our work. It performs well and has reasonable computational complexity. Finally to enhance the reliability of signal reception, three different diversity schemes namely, Maximum Ratio Receive Combining, Space-time block coding and Space frequency block coding are discussed and implemented for SC-FDE system. Simulation results show that these diversity techniques outperform single carrier frequency-domain equalization employing single antenna.
Single Carrier Frequency Division Multiple Access (SC-FDMA) is a novel method of radio transmission under consideration for deployment in future cellular systems; specifically, in 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) systems. SC-FDMA has drawn great attention from the communications industry as an attractive alternative to Orthogonal Frequency Division Multiple Access (OFDMA). Introduction to Single Carrier FDMA places SC-FDMA in the wider context of wireless communications, providing the reader with an in-depth tutorial on SC-FDMA technology. The book introduces the reader to this new multiple access technique that utilizes single carrier modulation along with orthogonal frequency multiplexing and frequency domain equalization, plus its applications in communications settings. It considers the similarities with and differences from orthogonal frequency division modulation, multiplexing, and multiple access used extensively in cellular, broadcasting, and digital subscriber loop applications. Particular reference is made to the peak power characteristics of an SC-FDMA signal as an added advantage over OFDMA. Provides an extensive overview of the principles of SC-FDMA and its relation to other transmission techniques. Explains how the details of a specific implementation influence the tradeoffs among various figures of merit. Describes in detail the configuration of the SC-FDMA uplink transmission scheme published by 3GPP. Features link level simulation of an uplink SC-FDMA system using MATLAB. This is an essential text for industry engineers who are researching and developing 3GPP LTE systems. It is suitable for engineers designing wireless network equipment, handsets, data cards, modules, chipsets, and test equipment as well as those involved in designing LTE infrastructure. It would also be of interest to academics, graduate students, and industry researchers involved in advanced wireless communications, as well as business analysts who follow the cellular market.
The concepts of frequency domain equalization represent the most powerful strategies to combat time dispersion caused by multipath propagation in broadband wireless communication systems. Performing equalization in the frequency domain allows for a computational efficient implementation because the effort grows significantly lower with the bandwidth compared to equalization in the time domain. Two well known frequency domain concepts exist: OFDM (Orthogonal Frequency Division Multiplexing) and SC/ FDE (Single Carrier Transmission with Frequency Domain Equalization). While the interest on OFDM was almost overwhelming, the interest on SC/FDE has been growing rapidly only recently. A primary topic of this work is the extension and alternative formulation of the SC/FDE system as it is usually understood. Further more the basic concept is characterised in terms of equalization strategies, higher order modulation schemes, synchronization, channel estimation, channel coding or front-end implementation effort. Finally an overall comparison of OFDM and SC/FDE is carried out, characterising advantages and disadvantages.
Frequency-Domain Receiver Design for Doubly-Selective Channels discusses broadband wireless transmission techniques, which are serious candidates to be implemented in future broadband wireless and cellular systems, aiming at providing high and reliable data transmission and concomitantly high mobility. This book provides an overview of the channel impairments that may affect performance of single carrier and multi-carrier block transmission techniques in mobile environments. Moreover, it also provides a new insight into the new receiver designs able to cope with double selectivity that affects present and future broadband high speed mobile communication systems.
Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative cove
Abstract: Wireless communication systems targeting at broadband and mobile transmissions commonly face the challenge of fading channels that are both time and frequency selective. Therefore, design of effective equalization and estimation algorithms for such channels becomes a fundamental problem. Although multi-carrier transmissions demonstrate prominent potential to combat doubly selective fading, several factors may retard their applications, such as: high peak-to-average power ratio, sensitivity to phase noise, etc. Meanwhile, single-carrier transmission is a conventional approach and has important applications, such as HDTV broadcasting, underwater acoustic communication. In this dissertation, we focus on receiver design for single-carrier transmissions. Our goal is to design and develop a group of channel estimation and equalization algorithms in the frequency-domain, which enable high performance and low complexity reception of single-carrier transmissions through doubly selective channels. For single-carrier transmissions over moderately fast fading channels with long-delay spread, we present an improved iterative frequency-domain equalization (IFDE) algorithm based on soft-interference-cancellation (SIC) and propose a novel adaptive frequency-domain channel estimation (AFDCE) based on soft-input Kalman filter, where soft information feedback from the IFDE can be exploited in the channel estimator. Simulation results show that, compared to other existing schemes, the proposed scheme offers lower MSE in channel prediction, lower BER after decoding, and robustness to non-stationary channels. We extend the IFDE/AFDCE scheme to accommodate the application of digital television (DTV) signal reception. Compared with the traditional joint decision feedback equalization (DFE) /decoding plus frequency-domain least-mean-square (FDLMS) channel estimation approach, the proposed scheme achieves better performance at a fraction of the implementation cost. For very fast fading large-delay-spread channels, traditional FDE methods fail, because channel variation within a FFT block induces significant off-main-diagonal coefficients in the frequency domain. To conquer the problem, we apply Doppler channel shortening to shape the energy distribution of those coefficients and derive a pilot-aided MMSE estimator to estimate them for SIC. We also propose a novel IFDE by leveraging both the sparse structure of shortened channel and finite-alphabet property of transmitted symbols. Numerical results show that the proposed scheme has advantages over the well-known FIR-MMSE-DFE/RLS-CE scheme in both performance and complexity.
This book introduces the theoretical elements at the basis of various classes of algorithms commonly employed in the physical layer (and, in part, in MAC layer) of wireless communications systems. It focuses on single user systems, so ignoring multiple access techniques. Moreover, emphasis is put on single-input single-output (SISO) systems, although some relevant topics about multiple-input multiple-output (MIMO) systems are also illustrated. Comprehensive wireless specific guide to algorithmic techniques Provides a detailed analysis of channel equalization and channel coding for wireless applications Unique conceptual approach focusing in single user systems Covers algebraic decoding, modulation techniques, channel coding and channel equalisation
