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Cyclic prefix

About: Cyclic prefix is a(n) research topic. Over the lifetime, 4372 publication(s) have been published within this topic receiving 53263 citation(s).

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Papers
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Open accessJournal ArticleDOI: 10.1109/78.599949
Abstract: We present the joint maximum likelihood (ML) symbol-time and carrier-frequency offset estimator in orthogonal frequency-division multiplexing (OFDM) systems. Redundant information contained within the cyclic prefix enables this estimation without additional pilots. Simulations show that the frequency estimator may be used in a tracking mode and the time estimator in an acquisition mode.

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Topics: Carrier frequency offset (60%), Frequency offset (59%), Estimator (58%) ...read more

2,189 Citations


Journal ArticleDOI: 10.1109/TCOMM.2002.806518
B. Muquet1, Zhengdao Wang2, Georgios B. Giannakis2, M. de Courville1  +1 moreInstitutions (3)
Abstract: Zero padding (ZP) of multicarrier transmissions has been proposed as an appealing alternative to the traditional cyclic prefix (CP) orthogonal frequency-division multiplexing (OFDM) to ensure symbol recovery regardless of the channel zero locations. In this paper, both systems are studied to delineate their relative merits in wireless systems where channel knowledge is not available at the transmitter. Two novel equalizers are developed for ZP-OFDM to tradeoff performance with implementation complexity. Both CP-OFDM and ZP-OFDM are then compared in terms of transmitter nonlinearities and required power backoff. Next, both systems are tested in terms of channel estimation and tracking capabilities. Simulations tailored to the realistic context of the standard for wireless local area network HIPERLAN/2 illustrate the pertinent tradeoffs.

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Topics: Cyclic prefix (58%), Orthogonal frequency-division multiplexing (55%), IEEE 802.11a-1999 (54%) ...read more

801 Citations


Open accessJournal ArticleDOI: 10.1109/LWC.2017.2757490
Hao Ye1, Geoffrey Ye Li1, Biing-Hwang Juang1Institutions (1)
Abstract: This letter presents our initial results in deep learning for channel estimation and signal detection in orthogonal frequency-division multiplexing (OFDM) systems. In this letter, we exploit deep learning to handle wireless OFDM channels in an end-to-end manner. Different from existing OFDM receivers that first estimate channel state information (CSI) explicitly and then detect/recover the transmitted symbols using the estimated CSI, the proposed deep learning-based approach estimates CSI implicitly and recovers the transmitted symbols directly. To address channel distortion, a deep learning model is first trained offline using the data generated from simulation based on channel statistics and then used for recovering the online transmitted data directly. From our simulation results, the deep learning based approach can address channel distortion and detect the transmitted symbols with performance comparable to the minimum mean-square error estimator. Furthermore, the deep learning-based approach is more robust than conventional methods when fewer training pilots are used, the cyclic prefix is omitted, and nonlinear clipping noise exists. In summary, deep learning is a promising tool for channel estimation and signal detection in wireless communications with complicated channel distortion and interference.

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780 Citations


Journal ArticleDOI: 10.1109/26.545896
Abstract: In discrete multitone (DMT) transceivers an intelligent guard time sequence, called a cyclic prefix (CP), is inserted between symbols to ensure that samples from one symbol do not interfere with the samples of another symbol. The length of the CP is determined by the length of the impulse response of the effective physical channel. Using a long CP reduces the throughput of the transceiver, To avoid using a long CP, a short time-domain finite impulse response (FIR) filter is used to shorten the effective channels impulse response. This paper explores various methods of determining the coefficients for this time-domain filter. An optimal shortening and a least-squares (LS) approach are developed for shortening the channel's impulse response. To provide a computationally efficient algorithm a variation of the LS approach is explored. In full-duplex transceivers the length of the effective echo path impacts the computational requirements of the transceiver. A new paradigm of joint shortening is introduced and three methods are developed to jointly shorten the channel and the echo impulse responses in order to reduce the length of the CP and reduce computational requirements for the echo canceller.

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Topics: Finite impulse response (64%), Impulse response (59%), Cyclic prefix (54%) ...read more

548 Citations


Open accessPosted Content
Hao Ye1, Geoffrey Ye Li1, Biing-Hwang Juang1Institutions (1)
Abstract: This article presents our initial results in deep learning for channel estimation and signal detection in orthogonal frequency-division multiplexing (OFDM). OFDM has been widely adopted in wireless broadband communications to combat frequency-selective fading in wireless channels. In this article, we take advantage of deep learning in handling wireless OFDM channels in an end-to-end approach. Different from existing OFDM receivers that first estimate CSI explicitly and then detect/recover the transmitted symbols with the estimated CSI, our deep learning based approach estimates CSI implicitly and recovers the transmitted symbols directly. To address channel distortion, a deep learning model is first trained offline using the data generated from the simulation based on the channel statistics and then used for recovering the online transmitted data directly. From our simulation results, the deep learning based approach has the ability to address channel distortions and detect the transmitted symbols with performance comparable to minimum mean-square error (MMSE) estimator. Furthermore, the deep learning based approach is more robust than conventional methods when fewer training pilots are used, the cyclic prefix (CP) is omitted, and nonlinear clipping noise is presented. In summary, deep learning is a promising tool for channel estimation and signal detection in wireless communications with complicated channel distortions and interferences.

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Topics: Orthogonal frequency-division multiplexing (56%), Fading (55%), Communication channel (54%) ...read more

522 Citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20221
2021117
2020191
2019240
2018223
2017251

Top Attributes

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Topic's top 5 most impactful authors

Marc Moonen

30 papers, 642 citations

Xiang-Gen Xia

21 papers, 561 citations

Xianbin Wang

17 papers, 184 citations

Huseyin Arslan

17 papers, 258 citations

Behrouz Farhang-Boroujeny

17 papers, 211 citations

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