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Frame synchronizing method for time-domain synchronous orthogonal frequency-division duplex receiver and system

A technology of orthogonal frequency division and time domain synchronization, applied in orthogonal multiplexing systems, multi-carrier systems, multiplexing communication and other directions, it can solve the problem that the performance of the coarse symbol synchronization method cannot be guaranteed, and the correlation characteristics are not as good as PN. It can solve the problems of sequence, destroying the repeating characteristic of cyclic prefix, etc., to achieve the effect of small detection error probability, good autocorrelation performance, and improved detection performance.

Inactive Publication Date: 2005-10-05
TSINGHUA UNIV
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Problems solved by technology

Using CP for symbol synchronization can avoid sending additional special training sequences, but the correlation characteristics of CP are not as good as PN sequences, and there are other adjacent values ​​​​near the maximum peak value, resulting in misjudgment and low estimation accuracy
In addition, in the multipath fading channel, the intersymbol interference (ISI) caused by the multipath effect has destroyed the repetition characteristic of the cyclic prefix
In this case, the performance of the CP-based coarse symbol synchronization method cannot be guaranteed

Method used

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  • Frame synchronizing method for time-domain synchronous orthogonal frequency-division duplex receiver and system
  • Frame synchronizing method for time-domain synchronous orthogonal frequency-division duplex receiver and system
  • Frame synchronizing method for time-domain synchronous orthogonal frequency-division duplex receiver and system

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Embodiment Construction

[0070] The theoretical analysis and specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0071] The TDS-OFDM frame synchronization PN signal to be used by the frame synchronization (code acquisition) method proposed by the present invention is composed of a preamble buffer, a PN sequence and a post asynchronous buffer. The PN sequence has 255 symbols, and the pre-sync buffer and post-sync buffer of frame synchronization are defined as the cyclic extension of the PN sequence, and the total length N is 512. The PN sequence is defined as an 8-order m-sequence implemented by a Fibonacci-type linear feedback shift register (LFSR). Its characteristic polynomial is defined as x 8 +x 6 +x 5 +x+1. LFSR block diagram as shown in Figure 6 , the initial value determines the phase of the generated m-sequence. An 8th-order m-sequence is a periodic sequence with a period of K=255. based on Figure 6 The init...

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Abstract

Characters are that TDS - OFDM frame synchronization PN sequence adopted in the invention based on a group of displaced m sequence. Sliding correlation method is utilized to calculate correlativity between oversampled TDS - OFDM signal and local PN sequence. Peak detection is adopted to test correlative peak and location. Phase encoding for adjacent signal frames determines phase of PN sequence in each signal frame. Then, third correlative peak is utilized to determine whether signal is in real synchronization; if no, code capture program is restarted. Experimental verifies that after each frame is captured, timing error is ensured within minus or plus sampling interval / 2 in order to carry out timing track correctly.

Description

technical field [0001] The invention belongs to the technical field of digital television reception, and in particular relates to a frame synchronization method and system of a time domain synchronous orthogonal frequency division multiplexing (Time Domain Synchronous OFDM, TDS-OFDM) digital television receiver. Background technique [0002] Currently, there are three main transmission standards for terrestrial digital TV broadcasting in the world: [0003] 1) Trellis-Coded 8-Level Vestigial Side-Band (8-VSB) modulation system developed by the Advanced Television Systems Committee (ATSC) in the United States. [0004] 2) Coded Orthogonal Frequency Division Multiplexing (Coded Orthogonal Frequency Division Multiplexing, COFDM) modulation system adopted by European Digital Video Terrestrial Broadcasting-Terrestrial (DVB-T) standard. [0005] 3) Bandwidth Segmented Transmission (BST) Orthogonal Frequency Division Multiplexing OFDM modulation system adopted by Integrated Servic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J11/00H04L27/32H04N7/015
Inventor 杨知行杨林
Owner TSINGHUA UNIV
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