Frequency synchronization method and equipment for OFDM system

A system frequency and equipment technology, applied in the field of OFDM system frequency synchronization, can solve the problem of carrier frequency and sampling rate mismatch, achieve high estimation accuracy, and realize the effect of low complexity

CN102546514BInactive Publication Date: 2014-12-24BEIJING UNIV OF POSTS & TELECOMM
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2014-12-24
Estimated Expiration
Not applicable · inactive patent

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Abstract

The embodiment of the invention discloses a frequency synchronization method and equipment for an OFDM (Orthogonal Frequency Division Multiplexing) system. In the technical scheme provided by the embodiment of the invention, during frequency synchronization process of the OFDM system, a digital phase-locked loop mechanism is adopted to realize joint estimation of carrier wave frequency deviation and sampling frequency deviation when AD / DA and radio frequency are synchronic, when each frame updates the phase-locked loop state information, only the frequency-domain related characteristics of training symbols are required to be utilized for estimating the residual sampling frequency deviation, and then the residual carrier wave frequency deviation can be obtained through simple calculation, so as to update the frequency deviation estimation. The complexity in system implementation is extremely low, and besides, high estimation precision can be achieved when the digital phase-locked loop is in a locking state.
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Description

technical field

[0001] The present invention relates to the technical field of wireless communication, in particular to a method and equipment for OFDM system frequency synchronization. Background technique

[0002] Orthogonal Frequency Division Multiplexing (OFDM) belongs to a broadband multi-carrier modulation technology, which utilizes sub-carriers transmitted in parallel to complete high-speed data communication. In the OFDM system, the data transmission channel is divided into many orthogonal sub-channels. Each sub-channel can be regarded as a superposition of flat fading and Gaussian noise channels. The spectrum utilization rate is very high, which can effectively combat the multipath fading of wireless channels. .

[0003] However, the orthogonality between the subcarriers of the OFDM system is based on the complete synchronization of the carrier frequency and sampling frequency at both ends of the transceiver. Therefore, it is very necessary to study how to effectiv...

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Embodiment Construction

[0079] The technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Apparently, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0080] As mentioned in the background art, when the AD / DA and the radio frequency share the same clock, the carrier frequency and the sampling rate of the transmitting and receiving ends will not match, which will affect the signal transmission effect.

[0081] The following technical solutions are provided by the embodiments of the present invention to solve the above problems. In the technical solutions proposed by the embodiments of the present invention, it is assumed that the receiving...