Frequency synchronization method and equipment for OFDM system

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.

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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Problems solved by technology

[0011] Embodiments of the present invention provide a method and device for frequency synchronization of an OFDM system, which are used to solve the problem in the prior art between AD (Analog to Digital, analog-to-digital conversion) / DA (Digital to Analog, digital-to-analog conversion) and radio frequency In the case of a clock, the carrier frequency and sampling rate at both ends of the transceiver do not match the problem, and the frequency offset estimation accuracy of the receiver is improved by using digital phase-locked loop technology

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