A time synchronization method, device and equipment for dual-antenna transmit diversity

Abstract

The application discloses a time synchronization method, device and equipment of a dual-antenna transmission diversity, and relates to the field of dual-antenna transmission diversity. The method comprises the following steps: at a sending end, performing frequency domain CDD processing on one of two space-time streams, and adding a synchronization header to the two space-time streams, wherein the synchronization header comprises a long preamble formed by a 512-point M sequence, and the number of delay samples of the long preamble CDD processing is 256; at a receiving end, using a sliding search window with a value of 768 to obtain the time of three correlation peaks generated by the long preamble as a time synchronization point for time synchronization. The application can ensure that the second expected correct peak value is the highest in any complex multipath scenario, thereby avoiding synchronization errors in the complex multipath scenario and avoiding demodulation failure.

Description

Technical Field

[0001] This application relates to the field of dual-antenna transmit diversity, specifically to a time synchronization method, apparatus, and device for dual-antenna transmit diversity. Background Technology

[0002] When space and power consumption are severely limited for mobile aircraft, MISO (Multiple Input Single Output) multi-antenna technology is generally used to ensure robust uplink communication in complex multipath environments. For example, two antennas and two radio frequency channels are used at the ground end, while the mobile end uses one antenna and one radio frequency channel. To combat fast time-varying multipath channels (mobile aircraft speed 60m / s---400m / s), the uplink can adopt a communication system of MISO+STBC (Space-time block code)+OFDM (Orthogonal Frequency Division Multiplexing).

[0003] For the dual-transmitter, single-receiver MISO+STBC+OFDM communication system, a large amount of data shows that the organic combination of CDD (Cyclic Delay Diversity) technology and STBC coding technology has a strong advantage in resisting multipath interference.

[0004] Traditional SISO (Single Input Single Output) time synchronization algorithms typically use a local correlator to find the maximum correlation peak. Ultra-high latency CDD (Constant Delay Difference) technology, however, artificially creates multipath. If a traditional local correlator is still used, multiple correlation peaks will be generated. The highest correlation peak will be about half the height of the SISO peak, meaning a significant drop in synchronization detection performance. Furthermore, in complex multipath scenarios, the expected highest correlation peak position may become the second highest peak position, leading to a complete miscalculation of the time synchronization position and ultimately demodulation failure. Summary of the Invention

[0005] This application provides a time synchronization method, apparatus, and device for dual-antenna transmit diversity, which can solve the technical problem of inaccurate expected highest correlation peak position in the prior art.

[0006] In a first aspect, embodiments of this application provide a time synchronization method for dual-antenna transmit diversity, the time synchronization method comprising:

[0007] At the transmitting end, frequency domain CDD processing is performed on one of the two space-time streams, and a synchronization header is added to both space-time streams. The synchronization header includes a long header consisting of a 512-point M-sequence, and the number of delay samples processed by the CDD of the long header is 256.

[0008] At the receiving end, for the space-time stream after CDD processing at the transmitting end, a 768 sliding search window is used to obtain the values. The times when the three related peaks generated by the long leader are obtained at the same time are used as the time synchronization points for time synchronization.

[0009] In conjunction with the first aspect, in one implementation, the 512-point M sequence is divided into a first part C and a second part D of 256 points. In the long guide after CDD processing, the first half is the second part D and the second half is the first part C. The sliding search window is divided into three sub-windows of 256 points from left to right.

[0010] The three correlation peaks simultaneously acquired from the long guide include: the local correlation value of the second sub-window of the sliding search window and the first part C; the local correlation value of the first two sub-windows of the sliding search window and the long guide; and the local correlation value of the first sub-window of the sliding search window and the second part D.

[0011] In conjunction with the first aspect, in one implementation, the power adaptive correlation value of the time synchronization is:

[0012] m= S 2 / (P×1024 2 );

[0013] Where m represents the adaptive power correlation value, S represents the sum of the three local correlation values, and P represents the adaptive power value.

[0014] The value S is obtained by taking the modulus of the three local correlation values ​​and then adding them together.

[0015] The formula P = (p1 + p2) / 1024 is given, where p1 is the sum of power of the samples in the second sub-window of the sliding search window, and p2 is the sum of power of the samples in the first sub-window of the sliding search window.

[0016] In conjunction with the first aspect, in one embodiment, the addition of a synchronization header to the two space-time streams includes a short header consisting of multiple 256-point M-sequences; the number of delay samples in the short header is 128; and in the space-time stream, each short header is located in front of the long header.

[0017] In conjunction with the first aspect, in one implementation, at the transmitting end, before performing frequency domain CDD processing on one of the two space-time streams, the method further includes: after the source data is interleaved by concatenated coding, it is STBC encoded to obtain two space-time streams, which are then inserted with symbol-by-symbol comb pilots respectively.

[0018] After frequency domain CDD processing, the two space-time streams are transformed by IFFT and then framed in the time domain before being sent out. The synchronization header is used for time domain framing.

[0019] In conjunction with the first aspect, in one implementation, at the receiving end, the data sent from the transmitting end is received by filtering and down-sampling, and after frequency difference estimation and correction, digital AGC processing is performed, and then time synchronization is performed;

[0020] After time synchronization, FFT transformation and symbol-by-symbol LS channel estimation are performed, followed by Walsh decoding.

[0021] Secondly, embodiments of this application provide a time synchronization device for dual-antenna transmit diversity, comprising:

[0022] The CDD processing module is used to perform frequency domain CDD processing on one of the two space-time streams at the transmitting end.

[0023] A synchronization header generation module is set at the transmitting end and is used to generate and add synchronization headers for two space-time streams. The synchronization header includes a long header consisting of a 512-point M-sequence, and the long header CDD processes 256 delay samples.

[0024] The time synchronization module, located at the receiving end, is used to obtain the values ​​of the received space-time stream after CDD processing using a 768 sliding search window. The times of the three related peaks generated by the long guide simultaneously are used as the time synchronization points for time synchronization.

[0025] In conjunction with the second aspect, in one implementation, the 512-point M sequence is divided into a first part C and a second part D of 256 points. In the long guide after CDD processing, the first half is the second part D and the second half is the first part C. The sliding search window is divided into three sub-windows of 256 points from left to right.

[0026] The three correlation peaks simultaneously acquired by the long guide include: the local correlation value of the second sub-window of the sliding search window and the first part C; the local correlation value of the first two sub-windows of the sliding search window and the long guide; and the local correlation value of the first sub-window of the sliding search window and the second part D.

[0027] In conjunction with the second aspect, in one implementation, the power adaptive correlation value of the time synchronization is:

[0028] m= S 2 / (P×1024 2 );

[0029] Where m represents the adaptive power correlation value, S represents the sum of the three local correlation values, and P represents the adaptive power value.

[0030] The value S is obtained by taking the modulus of the three local correlation values ​​and then adding them together.

[0031] The formula P = (p1 + p2) / 1024 is given, where p1 is the sum of power of the samples in the second sub-window of the sliding search window, and p2 is the sum of power of the samples in the first sub-window of the sliding search window.

[0032] Thirdly, embodiments of this application provide a time synchronization device for dual-antenna transmit diversity. The time synchronization device includes a processor, a memory, and a time synchronization program stored in the memory and executable by the processor. When the time synchronization program is executed by the processor, it implements the steps of the above-described time synchronization method for dual-antenna transmit diversity.

[0033] The beneficial effects of the technical solutions provided in this application include:

[0034] By taking advantage of the known premise that the multipath extension amount is artificially created using CDD, the three peaks of the long leader obtained simultaneously by the sliding search window can be merged. This can not only increase the peak height to enhance the threshold performance of the synchronization algorithm, but also ensure that the second expected correct peak is the highest in any complex multipath scenario, thereby avoiding synchronization errors in complex multipath scenarios and preventing demodulation failure. Attached Figure Description

[0035] Figure 1 This is a schematic flowchart of the time synchronization method for dual-antenna transmit diversity in an embodiment of this application;

[0036] Figure 2 This is a schematic diagram of the first space-time stream synchronization header in the embodiments of this application;

[0037] Figure 3 This is a schematic diagram of the second space-time stream synchronization header in an embodiment of this application;

[0038] Figure 4 This embodiment of the application uses a conventional 512-point correlator to obtain three peak values.

[0039] Figure 5 This is a peak value diagram of a conventional correlator used in an embodiment of this application;

[0040] Figure 6 This is a schematic diagram of the normal peak value using a conventional correlator in another embodiment of the application;

[0041] Figure 7 This is a schematic diagram illustrating abnormal peak values ​​using a conventional correlator in another embodiment of the application;

[0042] Figure 8 This is a schematic diagram illustrating the use of a 768 sliding window to obtain three peak values ​​in an embodiment of this application;

[0043] Figure 9 for Figure 8 A schematic diagram of the peak values ​​obtained from the data. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0045] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0046] MISO: Multiple Input Single Output. The MISO multi-antenna technology used in this application is as follows: two antennas and two radio frequency channels are used at the ground end, and one antenna and one radio frequency channel are used at the mobile end.

[0047] CDD: Cyclic Delay Diversity. The principle of CDD technology is to artificially create virtual frequency-selective fading, transforming the spatial transmit diversity of two antennas into frequency diversity of subcarriers. This causes the subcarriers within an OFDM symbol to experience completely different fading on the two channels, one with a dual antenna and the other with a single antenna. This uncorrelated fading, through interleaving and channel coding, can achieve considerable frequency diversity gain. For the second antenna in a dual-antenna transmit diversity scenario, the cyclic delay must be greater than the maximum delay spread of the multipath channel to achieve optimal multipath resistance.

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0049] In the first aspect, embodiments of this application provide a time synchronization method for dual-antenna transmit diversity to solve the technical problem in the prior art where the position of the expected highest correlation peak is inaccurate, ensuring that the second expected correct peak is the highest in any complex multipath scenario, thereby avoiding synchronization errors in complex multipath scenarios.

[0050] like Figure 1As shown, this time synchronization method includes the following steps:

[0051] S1. At the transmitting end, for the two space-time streams, one of the space-time streams is subjected to frequency domain CDD processing, with a delay sample number of 256.

[0052] S2. Add a synchronization header to the two space-time streams. The synchronization header includes a long header, which consists of a 512-point M-sequence.

[0053] S3. At the receiving end, after receiving two space-time streams, for the space-time stream that has been processed by CDD at the sending end, a 768 sliding search window is used to obtain the value. The time when the three related peaks generated by the long leader are obtained at the same time is used as the time synchronization point, and time synchronization is performed using this time synchronization point.

[0054] In step S1 above, at the transmitting end, the source data is interleaved using concatenated coding and then STBC encoded to obtain two space-time streams, each using symbol-by-symbol comb pilot insertion. Then, one of the space-time streams undergoes frequency-domain CDD processing. The two space-time streams are then transformed by IFFT and time-domain framed before being transmitted, with the synchronization header used for time-domain framing. In this embodiment, the second space-time stream undergoes frequency-domain CDD processing.

[0055] Specifically, in the above steps, the transmitting end transmits the first space-time stream and the second space-time stream through two antennas respectively. The first space-time stream travels from the first transmitting antenna to the receiving antenna (located at the receiving end) through the first channel H11, and the second space-time stream travels from the second transmitting antenna to the receiving antenna through the second channel H21. The two space-time streams are combined at the receiving antenna.

[0056] In step S2 above, at the transmitting end, a synchronization header is generated for each of the two space-time streams. The synchronization header consists of a short header and a long header. The short header is composed of multiple 256-point M-sequences, denoted as PN_256. The long header is composed of multiple 512-point M-sequences, denoted as PN_512. For the short header, 128 CDD delay samples are used. For the long header, 256 CDD delay samples are used.

[0057] In this embodiment, let the first half of PN_256 be A and the second half be B. Let the first half of PN_512 be the first part C and the second half be the second part D. For example... Figure 2 The image shows the synchronization header of the first space-time stream. The second space-time stream undergoes frequency-domain CDD processing, and its synchronization header is shown below. Figure 3 As shown, after one CDD delay, the first half is the second part D, and the second half is the first part C.

[0058] When performing time synchronization, if a traditional 512-point correlator is used, three peaks will be generated, such as... Figure 4As shown, the peak generation process is illustrated by a fixed-length sliding search window moving from left to right.

[0059] For the second space-time stream, when the end of the sliding search window moves to half of the corresponding PN_512, i.e., at time T1, D in PN_512 (i.e., C+D) becomes the effective region of the relevant contribution. Figure 4 The black portion corresponding to T1 will generate the first peak at time T1.

[0060] When the end of the sliding search window moves to the end of the corresponding PN_512, i.e., at time T2, C and D in PN_512 (i.e., C+D) become the effective regions of the relevant contributions. Figure 4 The black portion corresponding to T2 will generate a second peak at time T2.

[0061] When the first segment of the sliding search window moves to half of the corresponding PN_512, i.e., at time T3, C and D in PN_512 (i.e., C+D) become the effective region of the relevant contribution. Figure 4 The black portion corresponding to T3 will generate a third peak at time T3.

[0062] When the first channel H11 is given an AWGN channel, the second channel H21 is given an AWGN channel, and the SNR is given as 15dB, the peak plot of the traditional correlator is as follows. Figure 5 As shown, the peak height is around 0.5, which is the correct time synchronization point. In contrast, the peak height in the SISO system can reach over 0.95 under the same conditions. The MISO communication system using ultra-high delay CDD technology experiences a roughly 100% decrease in synchronization performance. With the addition of complex multipath channels, the traditional 512-point correlator not only suffers a drop in synchronization threshold but is also highly likely to experience synchronization errors, leading to demodulation failure.

[0063] When the first channel H11 is given a 6-path channel, the second channel H21 is given a 6-path channel, and the SNR is given as 10dB, the normal peak diagram of the traditional correlator is as follows: Figure 6 As shown, the abnormal peak value of the traditional correlator is... Figure 7 As shown. For Figure 7 If the synchronization position is found by using the maximum value, it is obvious that the first peak value is synchronized, which is completely wrong. This will cause the subsequent FFT window position to be completely wrong, resulting in demodulation failure.

[0064] like Figure 8As shown, in step S3 above, the receiving end uses the complex sample sequence of the received space-time stream after digital AGC adjustment as the input sequence. A sliding search window with a length of 768 points is set, consisting of a first sub-window, a second sub-window, and a third sub-window from left to right, each sub-window corresponding to 256 points. The sliding search window moves relative to the input sequence from left to right, and when the three correlation peaks generated by the long leader are obtained, CORR1, CORR2, and CORR3 need to be calculated.

[0065] CORR1 is the local correlation value of the second sub-window of the sliding search window and the first part C; CORR2 is the local correlation value of the first two sub-windows (the first sub-window and the second sub-window) of the sliding search window and the long guide (the second part D and the first part C); CORR3 is the local correlation value of the first sub-window of the sliding search window and the second part D.

[0066] Step S3 above also includes: first taking the modulus of the three local correlation values, then summing them to obtain the total S. Then, the adaptive power value P is calculated according to P=(p1+p2) / 1024; where p1 is the power sum of 256 samples in the second sub-window of the sliding search window, and p2 is the power sum of 256 samples in the first sub-window of the sliding search window. Finally, according to the formula m=S... 2 / (P×1024 2 ), calculate the power adaptive correlation value m for time synchronization.

[0067] Then, slide the search window to another sample point and repeat step S3.

[0068] After performing correlation using the above method, with H11 and H21 given 6-path channels and SNR given 10dB, the obtained peak diagram is as follows. Figure 9 As shown, the height of the second peak is approximately twice that of the second peak in a traditional correlator, resulting in a significant performance improvement. Therefore, it can be guaranteed that in various complex multipath scenarios, the second correlation peak will always be the highest, eliminating the risk of time synchronization errors (synchronizing to a different peak).

[0069] In step S3 above, at the receiving end, the data sent from the transmitting end is received by filtering and downsampling, and after frequency difference estimation and correction, digital AGC processing is performed, followed by time synchronization; after time synchronization, FFT transformation and symbol-by-symbol LS channel estimation are performed, followed by Walsh decoding and subsequent processes.

[0070] On the other hand, embodiments of this application also provide a time synchronization device for dual-antenna transmit diversity, which can be used to implement the above-described synchronization method. This time synchronization device includes a CDD processing module, a synchronization header generation module, and a time synchronization module.

[0071] The CDD processing module is used to perform frequency domain CDD processing on one of the two space-time streams at the transmitting end.

[0072] A synchronization header generation module, located at the transmitting end, is used to generate and add synchronization headers for two space-time streams. The synchronization header includes a long header consisting of a 512-point M-sequence, and the long header CDD processes 256 delay samples.

[0073] The time synchronization module, located at the receiving end, is used to obtain the values ​​of the received space-time stream after CDD processing using a 768 sliding search window. The times of the three related peaks generated by the long guide simultaneously are used as the time synchronization points for time synchronization.

[0074] Furthermore, in one embodiment, the 512-point M-sequence generated by the synchronization head generation module is divided into a first part C and a second part D of 256 points. In the long header after CDD processing, the first half is the second part D and the second half is the first part C. The sliding search window is divided into three sub-windows of 256 points from left to right.

[0075] The time synchronization module simultaneously acquires three correlation peaks generated by the long guide, including: the local correlation value of the second sub-window of the sliding search window and the first part C; the local correlation value of the first two sub-windows of the sliding search window and the long guide; and the local correlation value of the first sub-window of the sliding search window and the second part D.

[0076] The power adaptive correlation value m for time synchronization by the time synchronization module is:

[0077] m= S 2 / (P×1024 2 );

[0078] Where S represents the sum of the three local correlation values, and P represents the adaptive power value. S is obtained by taking the modulus of the three local correlation values ​​and then adding them together. P = (p1 + p2) / 1024, where p1 is the power sum of the samples in the second sub-window of the sliding search window, and p2 is the power sum of the samples in the first sub-window of the sliding search window.

[0079] Thirdly, embodiments of this application provide a time synchronization device for dual-antenna transmit diversity. The time synchronization device can be a communication device such as a mobile aircraft. The time synchronization device includes a processor, a memory, and a time synchronization program stored in the memory and executable by the processor. When the time synchronization program is executed by the processor, it implements the steps of the aforementioned time synchronization method.

[0080] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0081] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0082] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0083] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0084] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0085] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A time synchronization method for dual-antenna transmit diversity, characterized in that, The time synchronization method includes: At the transmitting end, frequency domain CDD processing is performed on one of the two space-time streams, and a synchronization header is added to both space-time streams. The synchronization header includes a long header consisting of a 512-point M-sequence, and the number of delay samples processed by the CDD of the long header is 256. At the receiving end, for the space-time stream after CDD processing at the transmitting end, a 768 sliding search window is used to obtain the values. The times when the three related peaks generated by the long leader are obtained at the same time are used as the time synchronization points for time synchronization.

2. The time synchronization method for dual-antenna transmit diversity as described in claim 1, characterized in that: The 512-point M sequence is divided into a first part C and a second part D, each with 256 points. In the long guide after CDD processing, the first half is the second part D and the second half is the first part C. The sliding search window is divided into three sub-windows with 256 points each from left to right. The three correlation peaks simultaneously acquired from the long guide include: the local correlation value of the second sub-window of the sliding search window and the first part C; the local correlation value of the first two sub-windows of the sliding search window and the long guide; and the local correlation value of the first sub-window of the sliding search window and the second part D.

3. The time synchronization method for dual-antenna transmit diversity as described in claim 2, characterized in that, The power adaptive correlation value for time synchronization is: m=S 2 / (P×1024 2 ); Where m represents the adaptive power correlation value, S represents the sum of the three local correlation values, and P represents the adaptive power value. The value S is obtained by taking the modulus of the three local correlation values ​​and then adding them together. The P = (p1 + p2) / 1024, where p1 is the sum of power of the samples in the second sub-window of the sliding search window, and p2 is the sum of power of the samples in the first sub-window of the sliding search window.

4. The time synchronization method for dual-antenna transmit diversity as described in claim 1, characterized in that: The process involves adding synchronization headers to the two space-time streams. Each synchronization header includes a short header consisting of multiple 256-point M-sequences. The number of delay samples in each short header is 128. In the space-time stream, each short header is located in front of the long header.

5. The time synchronization method for dual-antenna transmit diversity as described in claim 1, characterized in that, At the transmitting end, before performing frequency domain CDD processing on one of the two space-time streams, the process further includes: after the source data is interleaved by concatenated coding, it is STBC encoded to obtain two space-time streams, which are then inserted with symbol-by-symbol comb pilots respectively. After frequency domain CDD processing, the two space-time streams are transformed by IFFT and then framed in the time domain before being sent out. The synchronization header is used for time domain framing.

6. The time synchronization method for dual-antenna transmit diversity as described in claim 5, characterized in that: At the receiving end, the data received from the transmitting end is filtered and depressed, then subjected to frequency difference estimation and correction, digital AGC processing, and finally time synchronization. After time synchronization, FFT transformation and symbol-by-symbol LS channel estimation are performed, followed by Walsh decoding.

7. A time synchronization device for dual-antenna transmit diversity based on the time synchronization method of claim 1, characterized in that, include: The CDD processing module is used to perform frequency domain CDD processing on one of the two space-time streams at the transmitting end. A synchronization header generation module is set at the transmitting end and is used to generate and add synchronization headers for two space-time streams. The synchronization header includes a long header consisting of a 512-point M-sequence, and the long header CDD processes 256 delay samples. The time synchronization module, located at the receiving end, is used to obtain the values ​​of the received space-time stream after CDD processing using a 768 sliding search window. The times of the three related peaks generated by the long guide simultaneously are used as the time synchronization points for time synchronization.

8. The time synchronization device for dual-antenna transmit diversity as described in claim 7, characterized in that, The 512-point M sequence is divided into a first part C and a second part D, each with 256 points. In the long guide after CDD processing, the first half is the second part D and the second half is the first part C. The sliding search window is divided into three sub-windows with 256 points each from left to right. The three correlation peaks simultaneously acquired by the long guide include: the local correlation value of the second sub-window of the sliding search window and the first part C; the local correlation value of the first two sub-windows of the sliding search window and the long guide; and the local correlation value of the first sub-window of the sliding search window and the second part D.

9. The time synchronization device for dual-antenna transmit diversity as described in claim 8, characterized in that, The power adaptive correlation value for time synchronization is: m=S 2 / (P×1024 2 ); Where m represents the adaptive power correlation value, S represents the sum of the three local correlation values, and P represents the adaptive power value. The value S is obtained by taking the modulus of the three local correlation values ​​and then adding them together. The P = (p1 + p2) / 1024, where p1 is the sum of power of the samples in the second sub-window of the sliding search window, and p2 is the sum of power of the samples in the first sub-window of the sliding search window.

10. A time synchronization device for dual-antenna transmit diversity, characterized in that, The time synchronization device includes a processor, a memory, and a time synchronization program stored in the memory and executable by the processor, wherein when the time synchronization program is executed by the processor, it implements the steps of the time synchronization method for dual-antenna transmit diversity as described in any one of claims 1 to 6.

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