Journal ArticleDOI
Low-complexity equalization of OFDM in doubly selective channels
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TLDR
This work proposes a novel two-stage equalizer whose complexity (apart from the FFT) is linear in the OFDM symbol length, and results indicate that the equalizer has significant performance and complexity advantages over the classical linear MMSE estimator in doubly selective channels.Abstract:
Orthogonal frequency division multiplexing (OFDM) systems may experience significant inter-carrier interference (ICI) when used in time- and frequency-selective, or doubly selective, channels. In such cases, the classical symbol estimation schemes, e.g., minimum mean-squared error (MMSE) and zero-forcing (ZF) estimation, require matrix inversion that is prohibitively complex for large symbol lengths. An analysis of the ICI generation mechanism leads us to propose a novel two-stage equalizer whose complexity (apart from the FFT) is linear in the OFDM symbol length. The first stage applies optimal linear preprocessing to restrict ICI support, and the second stage uses iterative MMSE estimation to estimate finite-alphabet frequency-domain symbols. Simulation results indicate that our equalizer has significant performance and complexity advantages over the classical linear MMSE estimator in doubly selective channels.read more
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Journal ArticleDOI
Modulation Formats and Waveforms for 5G Networks: Who Will Be the Heir of OFDM?: An overview of alternative modulation schemes for improved spectral efficiency
Paolo Banelli,Stefano Buzzi,Giulio Colavolpe,Andrea Modenini,Fredrik Rusek,Alessandro Ugolini +5 more
TL;DR: This article provides a review of some modulation formats suited for 5G, enriched by a comparative analysis of their performance in a cellular environment, and by a discussion on their interactions with specific 5G ingredients.
Journal ArticleDOI
Pilot-Assisted Time-Varying Channel Estimation for OFDM Systems
TL;DR: This paper proposes novel channel estimators to combat both the noise and the out-of-band interference in orthogonal frequency-division multiplexing (OFDM) systems.
Journal ArticleDOI
Compressive Estimation of Doubly Selective Channels in Multicarrier Systems: Leakage Effects and Sparsity-Enhancing Processing
TL;DR: This work proposes a sparsity-enhancing basis expansion and a method for optimizing the basis with or without prior statistical information about the channel, and presents an alternative CS-based channel estimator, which is capable of estimating the off-diagonal channel coefficients characterizing intersymbol and intercarrier interference (ISI/ICI).
Journal ArticleDOI
Simple equalization of time-varying channels for OFDM
TL;DR: A block minimum mean-squared error (MMSE) equalizer for orthogonal frequency-division multiplexing (OFDM) systems over time-varying multipath channels is presented and turns out to be smaller than a serial MMSE equalizer characterized by a similar performance.
References
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Book
Discrete-Time Signal Processing
TL;DR: In this paper, the authors provide a thorough treatment of the fundamental theorems and properties of discrete-time linear systems, filtering, sampling, and discrete time Fourier analysis.
Book
Microwave Mobile Communications
William C. Jakes,Donald C. Cox +1 more
TL;DR: An in-depth and practical guide, Microwave Mobile Communications will provide you with a solid understanding of the microwave propagation techniques essential to the design of effective cellular systems.
Digital communications
TL;DR: This month's guest columnist, Steve Bible, N7HPR, is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California, and his research area closely follows his interest in amateur radio.