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Synchronized method of orthogonal frequency division multiplexing (OFDM) system

A coarse synchronization and fine synchronization technology, applied in the direction of multi-frequency code system, etc., can solve the problems of sensitivity to influence, residual estimation deviation, OFDM system influence, etc., and achieve the effect of improving performance and reducing complexity

Inactive Publication Date: 2011-05-25
深圳市阿派斯实业有限公司
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Problems solved by technology

For the above three types of synchronization, due to the influence of noise and the accuracy of the algorithm itself, residual estimation deviations will be left, and these residual deviations will also affect OFDM systems, especially for OFDM systems with high-order modulation. sensitive

Method used

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  • Synchronized method of orthogonal frequency division multiplexing (OFDM) system
  • Synchronized method of orthogonal frequency division multiplexing (OFDM) system
  • Synchronized method of orthogonal frequency division multiplexing (OFDM) system

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Embodiment 1

[0010] Embodiment 1. This embodiment provides a method for synchronization in an OFDM system. A short training sequence and a long training sequence for realizing synchronization and channel estimation functions are set at the sending end. The structure of the training sequence is as follows: figure 1 As shown, these sequences will be received in sequence at the receiving end. It is necessary to insert discrete frequency-domain pilots for phase deflection estimation into the data symbols, and the positions of the scattered pilots are symmetrical with respect to the 0 frequency point and are equally spaced. Process such as figure 2 As shown, the dotted box and dotted line in the figure represent the use of training sequence processing, wherein the thick dotted box and thick dotted line represent the need to process twice, and the solid line box and solid line represent received data symbol processing. The processing steps are as follows:

[0011] Step 1: Use the first two sh...

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Abstract

The invention provides a synchronized method of an orthogonal frequency division multiplexing (OFDM) system. The invention discloses an associated synchronized method of frame synchronization, carrier frequency synchronization and sampling clock synchronization. Carrier frequency offset estimation, channel estimation and fine estimation of symbol timing offset are performed again after sampling clock offset correction is finished, thereby avoiding influences of sampling clock offset on the carrier frequency offset estimation, the channel estimation and the fine estimation of the symbol timing offset, compensating phase deflection caused by the residual carrier frequency offset and the sampling clock offset simultaneously, greatly improving the synchronized performance, and meeting the demands of a high-order modulated system. In addition, due to aiming at a low time-varying channel, the channel estimation is required to be performed once only, thereby reliving the complexity of the system.

Description

technical field [0001] The invention belongs to the technical field of communication and relates to a synchronization method, in particular to a synchronization method of an OFDM system in which three synchronization modes of symbol timing synchronization, carrier frequency synchronization and sampling clock synchronization are used for joint synchronization in an OFDM system. Background technique [0002] OFDM (Orthogonal Frequency Division Multiplexing) system synchronization mainly includes three types of synchronization: symbol timing synchronization (frame synchronization), carrier frequency synchronization, and sampling clock synchronization. In an OFDM system, due to path delay, when receiving continuous data or burst frames, if the symbol or frame start position is wrongly estimated, the FFT window will be shifted and data errors will be introduced. The mismatch of the oscillator frequency at the transmitting end and the receiving end results in a mismatch between th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
Inventor 徐娟娟祝常健牛丽仙孙洪亮林炀炀任丽丽邢增谋
Owner 深圳市阿派斯实业有限公司
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