Method of synchronization of orthogonal frequency division multiplexing system frequency

Abstract

The invention provides a frequency synchronization method for an orthogonal frequency division multiplexing system, comprising the following steps of: S102, inserting a first training sequence in a sending signal at a transmission end, and performing inverse fast Fourier transform and associated treatments to the first training sequence as a local sequence stored in a register; S104, inserting a second training sequence in the sending signal at the transmission end, and performing inverse fast Fourier transform and associated treatments to the second training sequence; S106, carrying out coarse frequency synchronization to the received data at a receiving end to attain the coarse frequency-synchronized data; and S108, carrying out the thin frequency synchronization to the coarse frequency-synchronized data to attain the thin frequency-synchronized data. Therefore, estimation range for frequency offset can be efficiently enlarged in the presence of guarantee of good precision, thus diminishing the operation complexity and lessening the system expenditure.

Description

technical field [0001] The invention relates to a frequency synchronization method of an orthogonal frequency division multiplexing system, which is mainly applied to a new generation of cellular mobile communication systems, wireless local area networks, and wireless and wired transmission systems based on the orthogonal frequency division multiplexing system. Background technique [0002] As early as the mid-1960s, in the case of fully utilizing the effective bandwidth, overlapping sub-channels are used to avoid the use of high-speed equalizers, thereby resisting impulse noise and multipath effects, which are characterized by sub-carrier Orthogonal between. This system is called Orthogonal Frequency Division Multiplexing system, or OFDM system for short. [0003] Due to the oscillator frequency mismatch between the transmitter and receiver in the system, the jitter of the oscillation frequency caused by thermal drift, and the Doppler frequency shift, the frequency offset ...

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Problems solved by technology

This is difficult to satisfy for a high-efficiency OFDM system; and

[0009] B. Utilizing the characteristics of signal phase shift in the time domain, use the received training sequence or guard interval CP (Cyclic Prefix) as an autocorrelation operation to estimate the frequency offset. This method is simple to operate. When it is estimated in some special training sequence or CP The accuracy is also very high, but the estimation range of this method is very limited. In the actual system, the CP estimation method is easily affected by the interference between subcarriers.

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