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Improved time synchronization method

A technology of time synchronization and synchronization sequence, which is applied in communication between multiple stations, radio/inductive link selection arrangement, selection device, etc., can solve the problems of correlation disappearance, synchronization head correlation decline, and enlargement, etc. Achieve the effect of solving the sharp drop, avoiding double calculation, and improving synchronization efficiency

Inactive Publication Date: 2007-12-26
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

The frequency offset will cause the phase difference between the received signal and the local sequence to gradually increase over time, resulting in a sharp decline in the overall correlation of the sync head. When the variation range of the phase difference reaches 2π, the correlation basically disappears

Method used

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Embodiment Construction

[0021] The present invention has been verified in an OFDM system used for short-wave communication. The specific configuration of the parameters of the synchronous part of the system is given below, and the specific implementation steps of the present invention are described.

[0022] Sync header parameters:

[0023] Sampling rate: 40.96KHz

[0024] Signal bandwidth: 12KHz

[0025] Length of each synchronization sequence: 256 points

[0026] Number of synchronous sequence segments: 8 segments

[0027] Receive sequence segmentation points: 1792 points

[0028] Firstly, the 8-segment 256-point synchronous sequence is reversed to obtain the conjugate, then zero-filled to 2048 points, and then FFT is performed, stored at the local receiving end, and the square sum of each segment of the local sequence is stored at the same time.

[0029] The synchronization process is divided into the following steps:

[0030] Step 1: Divide the received sequence into a segment according to 1...

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Abstract

Regarding the influence of signal noise and signal offset to the sync performance, the invention provides a sync sequence design solution which divides the sync sequence into multi shorter-length segments; making correlated calculation for the received signals and each segment so as to generate multi correlation curves which are delayed and summarized to find the correlated peak and to complete the sync.

Description

technical field [0001] The invention relates to the field of wireless communication, in particular to the problem of time synchronization in the field of wireless communication. Background technique [0002] In the communication system, the time synchronization module is used to find the starting position of the useful signal, which is the first step for the reliable operation of the system. The channel quality of the wireless channel is relatively poor, not only there is a serious multipath fading phenomenon but also a large noise interference, such as a typical short-wave communication channel, the signal-to-noise ratio can be as low as -3dB. In addition, because the carrier frequency of the transmitter and the receiver and the sampling rate of the signal cannot be completely consistent, there is still a certain degree of frequency offset in the frequency-converted signal. When using local sequence synchronization, the frequency offset has a great influence on the synchro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04Q7/38H04B7/26H04L27/26
Inventor 徐大专王磊
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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