Symbol timing offset (STO) correction in orthogonal frequency division multiplexing (OFDM) based systems
03 Apr 2014-pp 508-512
TL;DR: The effect of STO on received OFDM symbols have been examined, frequency domain STO estimation and correction scheme have been studied and analyzed and STO should be effectively estimated and compensated to avoid throughput loss.
Abstract: OFDM is a Multicarrier modulation (MCM) technique, which in used in 4G standards. In OFDM systems, symbols are transmitted in parallel on several narrowband subcarriers, which are overlapping and orthogonal to each other. OFDM is superior to other systems because it incurs zero Inter Symbol Interference (ISI) or less amount of ISI which can be compensated by a single tap equalizer. OFDM is advantageous only when the orthogonality between the subcarriers is maintained. STO introduces phase shift, ISI and Inter Carrier Interference (ICI). Phase shift and ISI can be effectively compensated by using Cyclic Prefix (CP) but the effect of ICI introduces loss of orthogonality which causes severe loss in throughput. That is why STO should be effectively estimated and compensated to avoid throughput loss. In this paper the effect of STO on received OFDM symbols have been examined. Furthermore, frequency domain STO estimation and correction scheme have been studied and analyzed.
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16 Nov 2010TL;DR: In this article, the authors provide a comprehensive introduction to the theory and practice of wireless channel modeling, OFDM, and MIMO, using MATLAB programs to simulate the various techniques on a wireless network.
Abstract: MIMO-OFDM is a key technology for next-generation cellular communications (3GPP-LTE, Mobile WiMAX, IMT-Advanced) as well as wireless LAN (IEEE 802.11a, IEEE 802.11n), wireless PAN (MB-OFDM), and broadcasting (DAB, DVB, DMB). In MIMO-OFDM Wireless Communications with MATLAB, the authors provide a comprehensive introduction to the theory and practice of wireless channel modeling, OFDM, and MIMO, using MATLAB programs to simulate the various techniques on MIMO-OFDM systems. One of the only books in the area dedicated to explaining simulation aspects Covers implementation to help cement the key concepts Uses materials that have been classroom-tested in numerous universities Provides the analytic solutions and practical examples with downloadable MATLAB codes Simulation examples based on actual industry and research projects Presentation slides with key equations and figures for instructor use MIMO-OFDM Wireless Communications with MATLAB is a key text for graduate students in wireless communications. Professionals and technicians in wireless communication fields, graduate students in signal processing, as well as senior undergraduates majoring in wireless communications will find this book a practical introduction to the MIMO-OFDM techniques. Instructor materials and MATLAB code examples available for download at www.wiley.com/go/chomimo
1,413 citations
25 Nov 2001
TL;DR: A pilot-aided sampling and carrier frequency offset estimator in orthogonal frequency-division multiplexing (OFDM) systems and time-domain signal processing algorithms for carrier and sampling frequency offset correction are proposed.
Abstract: In this paper, we present a pilot-aided sampling and carrier frequency offset estimator in orthogonal frequency-division multiplexing (OFDM) systems. The proposed algorithm enables joint carrier and sampling frequency-offset estimation from a pilot whose duration is only two symbol periods. Furthermore, we propose time-domain signal processing algorithms for carrier and sampling frequency offset correction, which do not require time-consuming signal interpolation, and with which fixed free-running oscillators can be used. The performance of the proposed algorithms is studied through simulations, and compared to the performance of the other algorithms described in the literature.
77 citations
TL;DR: A digital modulation system using orthogonal frequency division and multiplexing (OFDM) is addressed, which presents the advantage of coping with echoes more easily than classical single-carrier modems, thanks to the insertion of a guard interval between two symbols.
Abstract: A digital modulation system using orthogonal frequency division and multiplexing (OFDM) is addressed in this paper. Such a system presents the advantage of coping with echoes more easily than classical single-carrier modems, thanks to the insertion of a guard interval between two symbols. The signal equalization is then achieved in the frequency domain. This OFDM modem is improved by using dual polarizations. In this configuration, it can convey a 70 Mbits/s (HDTV) bit stream in an 8 MHz UHF channel. Some experimental results relate field trials carried out in several countries with such equipment.
75 citations
01 Aug 1996
TL;DR: The features and functions of a newly developed Eureka-147 DAB (Digital Audio Broadcasting) receiver are described and an AFC (Automatic Frequency Control) and a synchronization technique using a DSP are described.
Abstract: This paper describes the features and functions of the newly developed Eureka-147 DAB (digital audio broadcasting) receiver. In this paper, we also describe an AFC (automatic frequency control) and a synchronization technique using a DSP (digital signal processor).
70 citations
02 Sep 2001
TL;DR: A novel sampling frequency offset estimation algorithm is proposed, which is based on the repetition of a symbol at the communication start-up, and a sampling frequency correction algorithm that does not require interpolation of signal samples is presented.
Abstract: In orthogonal frequency division multiplexing (OFDM) systems, symbols are transmitted in parallel on several narrow-band subchannels, which are overlapping and orthogonal. Modulation and demodulation is achieved by using fast Fourier transform (FFT) algorithms. Mismatch in sampling frequencies between transmitter and receiver can lead to serious degradation due to the loss of orthogonality between the subcarriers. Therefore, the sampling frequency offset has to be estimated, and the error has to be compensated at the receiver side. In this paper, a novel sampling frequency offset estimation algorithm is proposed, which is based on the repetition of a symbol at the communication start-up. The estimate is calculated from the phase difference between successive symbols. Furthermore, a sampling frequency correction algorithm that does not require interpolation of signal samples is presented. Simulations were performed for both algorithms separately. High improvement in system performance was achieved.
60 citations