CN109936393B - A synchronization method and device suitable for extremely low reception rate - Google Patents
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Abstract
Description
技术领域technical field
本发明实施例涉及通信技术领域，尤其涉及一种适用于极低接收率的同步方法及装置。Embodiments of the present invention relate to the field of communication technologies, and in particular, to a synchronization method and device suitable for extremely low reception rates.
背景技术Background technique
量子通信是量子物理与经典通信相结合的新兴交叉学科，它是把量子态当作信息载体，借助于量子力学的基本原理进行信息编码、通信控制和安全传输。作为量子通信的重要组成部分，量子安全直接通信技术通过直接建立量子信道的方式进行通信，在信息传输过程中通信双方不需要事先确定秘钥，因此具有高安全，高容量等优点，是一种新型的安全通信技术。然而，当发送端将发送的信息通过相位调制加载到单光子上，并直接通过量子信道传输载有信息的单光子。然而由于量子信道的衰减效应以及单光子源的非理想特性，导致接收端只能接收到很少的单光子数，其单光子接收率通常在万分之四到千分之二之间。这就意味着接收端只能接收到很少的发送信息。并且由于时延和信道的衰减效应的作用，接收序列存在相移。如果不采用同步方法使得码元同步，将无法解扩得到正确的译码信息，导致译码失败而无法实现高效的通信。因此，码元同步是实现高效量子安全直接通信的必要条件。Quantum communication is an emerging interdisciplinary subject combining quantum physics and classical communication. It regards quantum states as information carriers and uses the basic principles of quantum mechanics for information encoding, communication control and secure transmission. As an important part of quantum communication, quantum secure direct communication technology communicates by directly establishing a quantum channel. In the process of information transmission, both parties do not need to determine the secret key in advance, so it has the advantages of high security and high capacity. It is a kind of New secure communication technology. However, when the sender loads the transmitted information onto the single photon through phase modulation, and directly transmits the information-carrying single photon through the quantum channel. However, due to the attenuation effect of the quantum channel and the non-ideal characteristics of the single-photon source, the receiving end can only receive a small number of single-photons, and the single-photon acceptance rate is usually between 4/10,000 and 2/1,000. This means that the receiver can only receive very little of the transmitted information. And due to the effect of the time delay and the fading effect of the channel, the received sequence has a phase shift. If the synchronization method is not used to synchronize the symbols, correct decoding information cannot be obtained by despreading, resulting in decoding failure and inability to achieve efficient communication. Therefore, symbol synchronization is a necessary condition for realizing efficient quantum-secure direct communication.
在现有的同步方案中，采用同步头和滑动相关法的同步方法最为普遍，同步头是采用一段特殊的序列，接收序列接收到这段特殊的码字信息后用于校准；滑动相关捕获法是一种时域串行移位搜索方法，在滑动搜索过程中，先让本地扩频码和接收信号的码速率不同，这就可以认为两个码此时相对滑动。首先，用本地扩频码发生器产生的扩频码对接收信号做相关，之后，通过与门限值进行比较判断是否满足门限条件，不断改变扩频码的相位状态直至满足门限值，完成相位捕获。然后由于量子安全直接通信的接收率太低，传统的同步方法无法实现同步。因此，设计出适用于量子安全直接通信的高性能、低实现复杂度的同步算法对于实现量子安全直接通信的具有重要的意义。Among the existing synchronization schemes, the synchronization method using the synchronization header and the sliding correlation method is the most common. The synchronization header adopts a special sequence, and the receiving sequence receives the special codeword information for calibration; the sliding correlation acquisition method It is a time-domain serial shift search method. During the sliding search process, the code rates of the local spreading code and the received signal are different first, so that the two codes can be considered to be sliding relatively at this time. First, correlate the received signal with the spread spectrum code generated by the local spread spectrum code generator, then compare with the threshold value to determine whether the threshold condition is met, and continuously change the phase state of the spread spectrum code until the threshold value is met. Phase capture. Then traditional synchronization methods cannot achieve synchronization because the reception rate of quantum-safe direct communication is too low. Therefore, it is of great significance to design a synchronization algorithm with high performance and low implementation complexity suitable for quantum secure direct communication for realizing quantum secure direct communication.
发明内容SUMMARY OF THE INVENTION
本发明实施例的目的是提供一种克服上述问题或者至少部分地解决上述问题的适用于极低接收率的同步方法及装置。The purpose of the embodiments of the present invention is to provide a synchronization method and device suitable for extremely low reception rates that overcome the above problems or at least partially solve the above problems.
为了解决上述技术问题，一方面，本发明实施例提供一种适用于极低接收率的同步方法，包括：In order to solve the above technical problems, on the one hand, an embodiment of the present invention provides a synchronization method suitable for extremely low reception rates, including:
将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；Compare each spread spectrum bit in the target spread spectrum sequence with each spread spectrum codeword sequence after the specific codeword space spread, respectively record the number of the same bits as a set of count values. The frequency sequence is the spreading sequence of the current information bit;
根据所述计数值，确定所述当前信息比特是否为同步位置。According to the count value, it is determined whether the current information bit is a synchronization position.
另一方面，本发明实施例提供一种适用于极低接收率的同步装置，包括：On the other hand, an embodiment of the present invention provides a synchronization device suitable for an extremely low reception rate, including:
比较模块，用于将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；The comparison module is used to compare each spread-spectrum bit in the target spread-spectrum sequence with each spread-spectrum codeword sequence after the specific codeword space spread, and record the number of the same bits as a set of count values. , the target spreading sequence is the spreading sequence of the current information bit;
同步模块，用于根据所述计数值，确定所述当前信息比特是否为同步位置。A synchronization module, configured to determine whether the current information bit is a synchronization position according to the count value.
再一方面，本发明实施例提供一种电子设备，包括：In another aspect, an embodiment of the present invention provides an electronic device, including:
存储器和处理器，所述处理器和所述存储器通过总线完成相互间的通信；所述存储器存储有可被所述处理器执行的程序指令，所述处理器调用所述程序指令能够执行上述的方法。A memory and a processor, the processor and the memory communicate with each other through a bus; the memory stores program instructions that can be executed by the processor, and the processor invokes the program instructions to execute the above-mentioned program instructions. method.
又一方面，本发明实施例提供一种非暂态计算机可读存储介质，其上存储有计算机程序，当所述计算机程序被处理器执行时，实现上述的方法。In another aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the foregoing method is implemented.
本发明实施例提供的适用于极低接收率的同步方法及装置，在较短的扩频周期下实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method and device suitable for an extremely low reception rate provided by the embodiments of the present invention realize fast complete synchronization in a short spread spectrum period, and make the despread information after synchronization basically consistent with the information under ideal synchronization conditions , so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors of the transmitted symbols in the quantum channel, thus solving the problem of reliable information transmission in quantum secure direct communication.
附图说明Description of drawings
图1为本发明实施例提供的适用于极低接收率的同步方法示意图；1 is a schematic diagram of a synchronization method suitable for an extremely low reception rate provided by an embodiment of the present invention;
图2为本发明实施例提供的Hadamard码字基矩阵示意图；2 is a schematic diagram of a Hadamard codeword base matrix provided by an embodiment of the present invention;
图3为本发明实施例提供的适用于极低接收率的同步装置示意图；3 is a schematic diagram of a synchronization device suitable for an extremely low reception rate provided by an embodiment of the present invention;
图4为本发明实施例提供的电子设备的结构示意图。FIG. 4 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.
具体实施方式Detailed ways
为了使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.
图1为本发明实施例提供的适用于极低接收率的同步方法示意图，如图1所示，本发明实施例提供一种适用于极低接收率的同步方法，该方法包括：FIG. 1 is a schematic diagram of a synchronization method applicable to an extremely low reception rate provided by an embodiment of the present invention. As shown in FIG. 1 , an embodiment of the present invention provides a synchronization method applicable to an extremely low reception rate. The method includes:
步骤S101、将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；Step S101, compare each spread spectrum bit in the target spread spectrum sequence with each spread spectrum codeword sequence after the specific codeword space spread, respectively record the number of the same bits as a set of count values, so The target spreading sequence is the spreading sequence of the current information bit;
步骤S102、根据所述计数值，确定所述当前信息比特是否为同步位置。Step S102, according to the count value, determine whether the current information bit is a synchronization position.
具体来说，一个量子通信系统包括：发送端、量子信道和接收端。Specifically, a quantum communication system includes: a sender, a quantum channel and a receiver.
在发送端，通过单光子源产生单光子信号，对单光子信号进行相位编码，编码产生的码字序列进行扩频，扩频之后产生多个扩频序列，一个信息比特对应一个扩频序列，一个扩频序列包括多个扩频比特，一个扩频序列中包括的扩频比特的个数为码字序列的扩频周期。最后，发送端将扩频产生的扩频比特经过量子信道传输到接收端。At the transmitting end, a single-photon signal is generated by a single-photon source, phase-encoding is performed on the single-photon signal, and the codeword sequence generated by the encoding is spread-spectrum, and after spectrum-spreading, multiple spread-spectrum sequences are generated. A spreading sequence includes a plurality of spreading bits, and the number of spreading bits included in a spreading sequence is the spreading period of the codeword sequence. Finally, the transmitting end transmits the spread spectrum bits generated by the spread spectrum to the receiving end through the quantum channel.
在接收端，接收扩频比特流，首先，要根据接收的扩频序列完成同步。At the receiving end, the spread spectrum bit stream is received. First, synchronization is performed according to the received spread spectrum sequence.
当接收端同步成功之后，进行解扩、译码，从而成功获取信息。After the synchronization is successful at the receiving end, despreading and decoding are performed to obtain information successfully.
下面以特定的码字空间为修正后的r阶Hadamard码字空间为例进行说明。特定的码字空间除了可以为修正后的r阶Hadamard码字空间，还可以为其他的码字空间。The following description will be given by taking the specific codeword space as the modified r-order Hadamard codeword space as an example. The specific codeword space can be not only the modified r-order Hadamard codeword space, but also other codeword spaces.
同步开始时，首先，将目标扩频序列中的每一扩频比特分别与修正后的r阶Hadamard码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，目标扩频序列为当前信息比特的扩频序列。修正后的r阶Hadamard码字空间中扩频码字序列的个数为2r+1，一组计数值共包含2r对计数值。When synchronization starts, first, compare each spreading bit in the target spreading sequence with each spreading codeword sequence after spatial spreading of the modified r-order Hadamard codeword, respectively record the number of identical bits, As a set of count values, the target spreading sequence is the spreading sequence of the current information bits. The number of spread spectrum codeword sequences in the modified r-order Hadamard codeword space is 2 r+1 , and a set of count values contains 2 r pairs of count values.
然后，根据计数值，确定当前信息比特是否为同步位置。Then, according to the count value, it is determined whether the current information bit is the synchronization position.
本发明实施例提供的适用于极低接收率的同步方法，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method applicable to the extremely low reception rate provided by the embodiment of the present invention realizes fast complete synchronization under the condition of extremely low reception rate and a short spread spectrum period, and makes the despread information after synchronization and the synchronization The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
在上述实施例的基础上，进一步地，On the basis of the above-mentioned embodiment, further,
所述将目标扩频序列中的每一扩频比特分别与修正后的r阶Hadamard码字空间扩频后的每一个扩频码字序列比较，具体包括：The step of comparing each spread-spectrum bit in the target spread-spectrum sequence with each spread-spectrum codeword sequence after spatial spreading of the modified r-order Hadamard codeword, specifically includes:
将所述目标扩频序列中的第1个扩频比特分别与所述修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k位比较，第2个扩频比特分别与所述修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k+1位比较，第3个扩频比特分别与所述修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k+2位比较，直到第N-k个扩频比特分别与所述修正后的r阶Hadamard码字空间的每一个扩频码字序列的第N位比较；Compare the first spread spectrum bit in the target spread spectrum sequence with the kth bit of each spread spectrum codeword sequence in the modified r-order Hadamard codeword space, respectively, and the second spread spectrum bit with The k+1th bit of each spread spectrum codeword sequence in the modified r-order Hadamard codeword space is compared, and the third spread spectrum bit is respectively compared with each spread spectrum of the modified rth-order Hadamard codeword space. The k+2 bit of the frequency codeword sequence is compared until the N-kth spread spectrum bit is respectively compared with the Nth bit of each spread spectrum codeword sequence in the modified r-order Hadamard codeword space;
其中，N为扩频码字的扩频周期。Among them, N is the spreading period of the spreading codeword.
具体来说，从接收目标扩频序列的第一个扩频比特开始，将目标扩频序列中的第1个扩频比特分别与修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k位比较，第2个扩频比特分别与修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k+1位比较，第3个扩频比特分别与修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k+2位比较，依次类推，直到第N-k个扩频比特分别与修正后的r阶Hadamard码字空间的每一个扩频码字序列的第N位比较，比较完成后，分别记录相同位的个数，得到2r+1个的计数值，一组计数值。Specifically, starting from receiving the first spreading bit of the target spreading sequence, compare the first spreading bit in the target spreading sequence with each spreading codeword in the modified r-order Hadamard codeword space respectively. The kth bit of the sequence is compared, the second spread spectrum bit is compared with the k+1th bit of each spread spectrum codeword sequence in the modified r-order Hadamard codeword space, and the third spread spectrum bit is compared with the modified The k+2 bit of each spreading codeword sequence in the r-order Hadamard codeword space is compared, and so on, until the Nkth spreading bit is respectively compared with each spreading code in the modified r-order Hadamard codeword space The Nth bit of the word sequence is compared. After the comparison is completed, the number of the same bits is recorded respectively, and the count value of 2 r+1 is obtained, which is a group of count values.
N为扩频码字的扩频周期，k为搜索起点，即，从修正后的r阶Hadamard码字空间的每一个扩频码字序列的第k位与目标扩频序列中的第1个扩频比特进行比较。N is the spreading period of the spreading codeword, k is the search starting point, that is, the kth bit of each spreading codeword sequence in the modified r-order Hadamard codeword space and the first one in the target spreading sequence spread-spectrum bits for comparison.
本发明实施例提供的适用于极低接收率的同步方法，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method applicable to the extremely low reception rate provided by the embodiment of the present invention realizes fast complete synchronization under the condition of extremely low reception rate and a short spread spectrum period, and makes the despread information after synchronization and the synchronization The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
在以上各实施例的基础上，进一步地，所述根据所述计数值，确定所述当前信息比特是否为同步位置，具体包括：Based on the above embodiments, further, determining whether the current information bit is a synchronization position according to the count value specifically includes:
若判断获知存在某一对计数值中的其中一个计数值大于第一阈值，且另一个计数值小于第二阈值，则确定所述当前信息比特为同步位置，系统进入同步状态，其中，所述第一阈值大于所述第二阈值，所述修正后的r阶Hadamard码字空间中扩频码字序列的个数为2r+1，所述计数值中共有2r对计数值。If it is determined that there is a pair of count values, one of the count values is greater than the first threshold and the other count value is less than the second threshold, then the current information bit is determined to be the synchronization position, and the system enters the synchronization state, wherein the The first threshold is greater than the second threshold, the number of spread spectrum codeword sequences in the modified r-order Hadamard codeword space is 2 r+1 , and there are 2 r pairs of count values in the count values.
具体来说，2r+1个计数值共有2r对计数值，针对计数值的大小进行分阶段的讨论，如果出现某一对计数值的其中一个值极大，另一个值几乎为0，即，如果存在某一对计数值中的其中一个计数值大于第一阈值，且另一个计数值小于第二阈值，则确定当前信息比特为同步位置，系统进入同步状态，其中，第一阈值大于第二阈值，第一阈值相对于第二阈值为极大值，第二阈值相对于第一阈值几乎为0，修正后的r阶Hadamard码字空间中扩频码字序列的个数为2r+1，计数值中共有2r对计数值。Specifically, 2 r+1 count values have a total of 2 r pairs of count values, and the size of the count values is discussed in stages. That is, if there is a pair of count values, one of which is greater than the first threshold and the other is less than the second threshold, the current information bit is determined to be the synchronization position, and the system enters the synchronization state, where the first threshold is greater than The second threshold, the first threshold is a maximum value relative to the second threshold, the second threshold is almost 0 relative to the first threshold, and the number of spreading codeword sequences in the modified r-order Hadamard codeword space is 2 r +1 , there are 2 r pairs of count values in the count value.
本发明实施例提供的适用于极低接收率的同步方法，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method applicable to the extremely low reception rate provided by the embodiment of the present invention realizes fast complete synchronization under the condition of extremely low reception rate and a short spread spectrum period, and makes the despread information after synchronization and the synchronization The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
在以上各实施例的基础上，进一步地，所述根据所述计数值，确定所述当前信息比特是否为同步位置，具体包括：Based on the above embodiments, further, determining whether the current information bit is a synchronization position according to the count value specifically includes:
若判断获知任一对计数值中的两个计数值之差的绝对值均小于第三阈值确不为零，则确定所述当前信息比特为非同步位置，系统进入失步状态。If it is determined that the absolute value of the difference between the two count values in any pair of count values is less than the third threshold and is not zero, then it is determined that the current information bit is an asynchronous position, and the system enters an out-of-sync state.
具体来说，每一对计数值的值都比较接近，即，任一对计数值中的两个计数值之差的绝对值均小于第三阈值确不为零，则确定当前信息比特为非同步位置，系统进入失步状态。Specifically, the values of each pair of count values are relatively close, that is, if the absolute value of the difference between the two count values in any pair of count values is smaller than the third threshold and is not zero, then it is determined that the current information bit is not zero. Synchronous position, the system goes out of sync.
本发明实施例提供的适用于极低接收率的同步方法，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method applicable to the extremely low reception rate provided by the embodiment of the present invention realizes fast complete synchronization under the condition of extremely low reception rate and a short spread spectrum period, and makes the despread information after synchronization and the synchronization The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
取2r对计数值，根据每一对计数值的大小，确定当前信息比特是否为同步位置。Take 2 r pairs of count values, and determine whether the current information bit is a synchronization position according to the size of each pair of count values.
本发明实施例提供的适用于极低接收率的同步方法，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization method applicable to the extremely low reception rate provided by the embodiment of the present invention realizes fast complete synchronization under the condition of extremely low reception rate and a short spread spectrum period, and makes the despread information after synchronization and the synchronization The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
下面以一个具体的例子，对上述方法进行详细说明：The above method is described in detail with a specific example below:
采用的是由码长为4000，码率为0.5的LDPC码和4阶Hadamard码字构成的级联码作为编码方法。Hadamard码的码字空间由基矩阵构造，图2为本发明实施例提供的Hadamard码字基矩阵示意图，如图2所示，每一个Hadamard码字之间都是正交，其中信息位为[0,20,21,...,2r-1]，最后一位是奇偶校验位。A concatenated code composed of an LDPC code with a code length of 4000 and a code rate of 0.5 and a fourth-order Hadamard codeword is used as the encoding method. The codeword space of the Hadamard code is constructed by a basis matrix. FIG. 2 is a schematic diagram of the basis matrix of the Hadamard codeword provided by an embodiment of the present invention. As shown in FIG. 2, each Hadamard codeword is orthogonal, and the information bits are [ 0,20,2 1 ,...,2 r-1 ], the last bit is the parity bit.
1)在发送端，通过单光子源产生单光子信号，对单光子信号进行相位编码，根据LDPC和Hadamard级联方式，将信息序列编码成由多个16位Hadamard码字相连，Hadamard码字之间满足LDPC的校验矩阵的编码序列。1) At the sending end, a single-photon signal is generated by a single-photon source, and the single-photon signal is phase-encoded. According to the LDPC and Hadamard concatenation method, the information sequence is encoded into a plurality of 16-bit Hadamard code words connected, and the Hadamard code words are connected together. The coded sequence of the parity check matrix that satisfies LDPC.
2)对每一个Hadamard码字进行扩频，扩频周期为64，扩频之后的新的码字长度为64*16，选取一段长度为64*16的伪随机序列，并将所有扩频后用于信息传输的码字序列与伪随机序列对应位置相乘，得到修正后的序列，修正后的序列相关性能好。将修正后的码字序列通过量子信道。2) Spread each Hadamard codeword, the spreading period is 64, the length of the new codeword after spreading is 64*16, select a pseudo-random sequence with a length of 64*16, and spread all the The codeword sequence used for information transmission is multiplied by the corresponding position of the pseudo-random sequence to obtain a modified sequence, and the modified sequence has good correlation performance. Pass the modified codeword sequence through the quantum channel.
3)在接收端，先将接收的每一帧进行存储，从接收的第一个比特开始，利用修正后的扩频Hadamard码字序列的相关性，将每一按顺序选择长度为64*16的码字序列与扩频修正后的码字空间的32个序列在状态机内进行比较。从接收序列的第一个扩频比特开始，每一个扩频周期的扩频比特分别与扩频修正后的Hadamard序列，根据设定的门限值判断当前比特的状态从而判断系统当前的状态，从而确定同步的位置。3) At the receiving end, first store each frame received, starting from the first bit received, using the correlation of the modified spread-spectrum Hadamard codeword sequence, select each frame in order with a length of 64*16 The codeword sequence is compared with the 32 sequences of the codeword space after the spread spectrum correction in the state machine. Starting from the first spread-spectrum bit of the received sequence, the spread-spectrum bits of each spread-spectrum cycle are respectively related to the Hadamard sequence after spread-spectrum correction, and the state of the current bit is judged according to the set threshold value to judge the current state of the system. Thereby, the position of synchronization is determined.
4)从接收到的第一个长度为64*16的序列开始，用32个特定序列进行移比较，每一次移位都得到16对计数值，存储经过了64*16次移位后的计数值，对于每一个特定的序列，找出满足阈值条件的值，并记下当前移位的位置，之后再选择接收的第二段长度为64*16的序列，与第一段序列相同，找出满足条件的位置，经过若干次比较后，找出出现次数最多的位置，该位置则是同步的位置。4) Starting from the first received sequence with a length of 64*16, use 32 specific sequences for shift comparison, each shift gets 16 pairs of count values, and stores the count after 64*16 shifts value, for each specific sequence, find the value that satisfies the threshold condition, and note the current shift position, and then select the second received sequence with a length of 64*16, which is the same as the first sequence, find Find the position that satisfies the condition, and after several comparisons, find the position with the most occurrences, which is the synchronized position.
对接收端在不同信号接收率下恢复的接收信息序列的误比特率(BER)进行了测试，测试结果如表1所示。在接收率大于等于0.004的条件下，实验结果的误码率和理想情况下的误码率是非常接近，可以表明，同步的性能几乎可以达到完全同步。The bit error rate (BER) of the received information sequence recovered by the receiver under different signal reception rates is tested. The test results are shown in Table 1. Under the condition that the reception rate is greater than or equal to 0.004, the bit error rate of the experimental results is very close to the ideal bit error rate, which shows that the synchronization performance can almost achieve complete synchronization.
表1测试结果Table 1 Test results
图3为本发明实施例提供的适用于极低接收率的同步装置示意图，如图3所示，本发明实施例提供一种适用于极低接收率的同步装置，用于执行上述任一实施例中所述的方法，具体包括比较模块301和同步模块302，其中：FIG. 3 is a schematic diagram of a synchronization apparatus suitable for an extremely low reception rate provided by an embodiment of the present invention. As shown in FIG. 3 , an embodiment of the present invention provides a synchronization apparatus suitable for an extremely low reception rate, which is used to perform any of the above implementations The method described in the example specifically includes a
比较模块301用于将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；同步模块301用于根据所述计数值，确定所述当前信息比特是否为同步位置。The
具体来说，一个量子通信系统包括：发送端、量子信道和接收端。Specifically, a quantum communication system includes: a sender, a quantum channel and a receiver.
在发送端，通过单光子源产生单光子信号，对单光子信号进行相位编码，编码产生的码字序列进行扩频，扩频之后产生多个扩频序列，一个信息比特对应一个扩频序列，一个扩频序列包括多个扩频比特，一个扩频序列中包括的扩频比特的个数为码字序列的扩频周期。最后，发送端将扩频产生的扩频比特经过量子信道传输到接收端。At the transmitting end, a single-photon signal is generated by a single-photon source, phase-encoding is performed on the single-photon signal, and the codeword sequence generated by the encoding is spread-spectrum, and after spectrum-spreading, multiple spread-spectrum sequences are generated. A spreading sequence includes a plurality of spreading bits, and the number of spreading bits included in a spreading sequence is the spreading period of the codeword sequence. Finally, the transmitting end transmits the spread spectrum bits generated by the spread spectrum to the receiving end through the quantum channel.
当接收端同步成功之后，进行解扩、译码，从而成功获取信息。After the synchronization is successful at the receiving end, despreading and decoding are performed to obtain information successfully.
当接收端根据当前信息比特没有同步成功时，需要根据下一信息比特的扩频序列进行同步，直到同步成功。When the receiver fails to synchronize successfully according to the current information bit, it needs to perform synchronization according to the spreading sequence of the next information bit until the synchronization is successful.
同步开始时，首先，通过比较模块301将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，目标扩频序列为当前信息比特的扩频序列。When the synchronization starts, firstly, each spread spectrum bit in the target spread spectrum sequence is compared with each spread spectrum codeword sequence after the specific codeword space spread by the
然后，通过同步模块302根据计数值，确定当前信息比特是否为同步位置。Then, the
本发明实施例提供的适用于极低接收率的同步装置，在极低的接收率条件下，在较短的扩频周期下，实现快速的完全同步，并且使得同步之后的解扩的信息与理想同步条件下的信息基本一致，使得整个通信系统与理论同步取得完全一致的性能，可以有效纠正传输符号在量子信道中发生的信息丢失和错误，从而解决了量子安全直接通信中信息的可靠传输问题。The synchronization device suitable for the extremely low reception rate provided by the embodiment of the present invention realizes the fast complete synchronization under the condition of the extremely low reception rate and the short spread spectrum period, and makes the despread information after synchronization and the The information under ideal synchronization conditions is basically consistent, so that the entire communication system achieves completely consistent performance with the theoretical synchronization, which can effectively correct the information loss and errors that occur in the transmission symbol in the quantum channel, thus solving the reliable transmission of information in quantum secure direct communication. question.
图4为本发明实施例提供的电子设备的结构示意图，如图4所示，所述设备包括：处理器(processor)401、存储器(memory)402和总线403；FIG. 4 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. As shown in FIG. 4 , the device includes: a processor (processor) 401, a memory (memory) 402, and a
其中，处理器401和存储器402通过所述总线403完成相互间的通信；Wherein, the
处理器401用于调用存储器402中的程序指令，以执行上述各方法实施例所提供的方法，例如包括：The
将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；Compare each spread spectrum bit in the target spread spectrum sequence with each spread spectrum codeword sequence after the specific codeword space spread, respectively record the number of the same bits as a set of count values. The frequency sequence is the spreading sequence of the current information bit;
根据所述计数值，确定所述当前信息比特是否为同步位置。According to the count value, it is determined whether the current information bit is a synchronization position.
此外，上述的存储器中的逻辑指令可以通过软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本发明各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random AccessMemory)、磁碟或者光盘等各种可以存储程序代码的介质。In addition, the above-mentioned logic instructions in the memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: U disk, removable hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.
本发明实施例提供一种计算机程序产品，所述计算机程序产品包括存储在非暂态计算机可读存储介质上的计算机程序，所述计算机程序包括程序指令，当所述程序指令被计算机执行时，计算机能够执行上述各方法实施例所提供的方法，例如包括：An embodiment of the present invention provides a computer program product, where the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, the computer program includes program instructions, and when the program instructions are executed by a computer, The computer can execute the methods provided by the above method embodiments, for example, including:
将目标扩频序列中的每一扩频比特分别与特定的码字空间的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；Compare each spread spectrum bit in the target spread spectrum sequence with each spread spectrum codeword sequence in a specific codeword space, respectively record the number of identical bits as a set of count values, and the target spread spectrum sequence is: the spreading sequence of the current information bits;
根据所述计数值，确定所述当前信息比特是否为同步位置。According to the count value, it is determined whether the current information bit is a synchronization position.
本发明实施例提供一种非暂态计算机可读存储介质，所述非暂态计算机可读存储介质存储计算机指令，所述计算机指令使所述计算机执行上述各方法实施例所提供的方法，例如包括：Embodiments of the present invention provide a non-transitory computer-readable storage medium, where the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions cause the computer to execute the methods provided by the foregoing method embodiments, for example include:
将目标扩频序列中的每一扩频比特分别与特定的码字空间扩频后的每一个扩频码字序列比较，分别记录相同位的个数，作为一组计数值，所述目标扩频序列为当前信息比特的扩频序列；Compare each spread spectrum bit in the target spread spectrum sequence with each spread spectrum codeword sequence after the specific codeword space spread, respectively record the number of the same bits as a set of count values. The frequency sequence is the spreading sequence of the current information bit;
根据所述计数值，确定所述当前信息比特是否为同步位置。According to the count value, it is determined whether the current information bit is a synchronization position.
以上所描述的装置及设备等实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。本领域普通技术人员在不付出创造性的劳动的情况下，即可以理解并实施。The above-described embodiments such as apparatuses and devices are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, That is, it can be located in one place, or it can be distributed to multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.
通过以上的实施方式的描述，本领域的技术人员可以清楚地了解到各实施方式可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件。基于这样的理解，上述技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品可以存储在计算机可读存储介质中，如ROM/RAM、磁碟、光盘等，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行各个实施例或者实施例的某些部分所述的方法。From the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and certainly can also be implemented by hardware. Based on this understanding, the above-mentioned technical solutions can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products can be stored in computer-readable storage media, such as ROM/RAM, magnetic A disc, an optical disc, etc., includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in various embodiments or some parts of the embodiments.
最后应说明的是：以上实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
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| CN103152071A (en) * | 2011-12-06 | 2013-06-12 | 福建联拓科技有限公司 | Method and equipment for searching synchronization sequence |
| CN104125053A (en) * | 2014-08-12 | 2014-10-29 | 电子科技大学中山学院 | Method and device for capturing synchronous frame |
| CN105049080A (en) * | 2015-08-25 | 2015-11-11 | 四川九洲电器集团有限责任公司 | Spread spectrum synchronization method and device based on adaptive threshold |
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| CN103152071A (en) * | 2011-12-06 | 2013-06-12 | 福建联拓科技有限公司 | Method and equipment for searching synchronization sequence |
| CN104125053A (en) * | 2014-08-12 | 2014-10-29 | 电子科技大学中山学院 | Method and device for capturing synchronous frame |
| CN105049080A (en) * | 2015-08-25 | 2015-11-11 | 四川九洲电器集团有限责任公司 | Spread spectrum synchronization method and device based on adaptive threshold |
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