Method for realizing synchronization of orthogonal frequency division multiplexing (OFDM) digital seismograph by utilizing complementary sequences
A complementary sequence and seismograph technology, applied in the field of oil and gas exploration, can solve the problems of unfavorable judgment synchronization and many side lobes of the objective function, and achieve the effect of reducing complexity and avoiding more side lobes
Inactive Publication Date: 2011-11-23
SOUTHWEST PETROLEUM UNIV
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Therefore, it can be considered that the objective function has more side lobes, which is not conducive to setting the threshold value to judge the synchronization
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[0089] A specific implementation method under the OFDM configuration of this patent is given below. It should be noted that the parameter settings in the following examples do not affect the generality of this patent.
[0090]Let the OFDM signed length be N=2048, the cyclic prefix length L=64, take , which means that the training sequence only accounts for 3% of the power of the transmitter. The channel model adopts the channel reference model of UMST (Universal Mobile Telecommunications System) in mountainous areas. The length of complementary sequence pairs is 16, as shown in Table 1:
[0091] Table 1 Complementary sequence pairs ( , )and( , )
[0092]
[0093] 1. Transmitter:
[0094] Two pairs of complementary sequence pairs according to the formula form a sequence of complex numbers and , with a length of 16. the complex sequence and After performing 16-point IFFT, merge sequences according to expression (3), with a length of 32; then, take the me...
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The invention provides an orthogonal frequency division multiplexing (OFDM)-based digital seismograph data transmission system synchronization method, which is characterized in that: a digital seismograph data transmission system adopts an advanced OFDM technology as a transmission mechanism; at a transmitter, a training sequence with conjugate anti-symmetry is constructed by utilizing complementary sequences and superposed on a cyclic prefix of OFDM; and at a receiver, a synchronization algorithm with a simple structure is designed to obtain a target function with single sharpness by utilizing the conjugate anti-symmetry of the training sequence, and synchronous judgment is performed by utilizing a preset threshold value to realize the rapid synchronization of an OFDM system. Compared with a conventional superposed periodic training sequence synchronization algorithm, the method has the advantages of low computational complexity and high synchronization speed, and can be adapted to digital seismograph data transmission systems realizing transmission at high rate as well as wireless communication systems adopting the OFDM technology.
Description
technical field [0001] The invention belongs to the field of oil and gas exploration, in particular to a system synchronization method using OFDM technology in a digital seismograph data transmission system in oil and gas seismic exploration. Background technique [0002] With the rapid development of the national economy, my country's demand for energy such as oil and minerals is becoming stronger and stronger. As a fast and efficient geophysical prospecting method, seismic prospecting has been widely used in the field of energy prospecting. As the key equipment for seismic exploration, more than 90% of digital seismographs rely on foreign imports, and domestic independent R&D investment is low, which seriously restricts the development of my country's seismic exploration. Although great progress has been made in the development of seismographs after years of efforts by domestic research institutions, the channel capacity of seismographs has been restricted by data transmi...
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IPC IPC(8): H04L27/26
Inventor 罗仁泽戈勇华黄元溢党煜蒲
Owner SOUTHWEST PETROLEUM UNIV