Ofdm symbol synchronization position search method and its synchronization device

Abstract

The invention discloses a search method for OFDM symbol synchronous position, which includes: firstly using the P1 symbol correlation result to perform edge detection on the P1 symbol correlation value, the specific method is: performing difference on the correlation value signal, and then performing moving average; The absolute value of the average output signal is searched, if it is greater than the predetermined threshold, continue to search for 5760Samples. The maximum peak is searched, and according to its polarity, two synchronization candidate points are given. Finally, the peak-to-noise ratio is calculated by using the two synchronization position candidate points given, and the synchronization candidate point with a larger peak-to-noise ratio is selected as the final synchronization point position. The invention also discloses an OFDM symbol synchronization device used in the method. The invention can reduce P1 symbol synchronization error under serious multipath interference channel, improve the performance of P1 symbol detection and decoding and P2 symbol decoding, and avoid system performance degradation caused by large P1 symbol synchronization error.

Description

technical field [0001] The invention relates to the field of communication, in particular to a method for searching the synchronous position of OFDM (orthogonal frequency division multiplexing) symbols of the second-generation European terrestrial digital television (DVB-T2). The invention also relates to an OFDM symbol synchronization device used in the method. Background technique [0002] OFDM technology is widely used in modern communication systems. As the second generation digital terrestrial television standard in Europe, DVB-T2 ("Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2)," ETSI EN 302755), inherited In OFDM technology of the first generation standard DVB-T, the basic unit of data is called T2 frame. Such as figure 1 Shown is a structure diagram of a T2 frame, and each frame includes a P1 preamble symbol, a P2 preamble symbol, and a data symbol ...

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Problems solved by technology

[0009] The above correlation peak method of P1 symbol detection can resist all kinds of serious interference and noise, but its disadvantage is that the error of the synchronization position is very large

[0010] 1) The positive correlation peak does not guarantee that the detected diameter is the anterior diameter (similarly, the negative correlation peak cannot guarantee the posterior diameter);

[0011] 2) Unable to handle Pre / Post Echo (that is, two-path channels with D / U not equal to 0dB);

[0012] 3) It is impossible to distinguish whether the correlation peak really contains superposition effects

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