Direct sequence spread spectrum communication method and system based on true random numbers

Abstract

The present invention relates to a direct sequence spread spectrum communication method and system based on true random numbers, which uses quantum keys to provide true random numbers for a direct sequence spread spectrum communication system, provides additional information entropy for spread spectrum code generation, increases unpredictability, and thus improves channel security. In the direct sequence spread spectrum communication system, a first quantum key distribution device and a second quantum key distribution device can be respectively arranged in a transmitter and a receiver, and the same quantum key is generated in the transmitter and the receiver through a quantum key distribution process by means of the first and second quantum key distribution devices, and a spread spectrum code is generated by using the quantum key, so as to spread a data signal and modulate a carrier signal by using the spread spectrum code, and despread and demodulate the spread spectrum signal.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a direct sequence spread spectrum communication method and system based on true random numbers. Background Art

[0002] The spread spectrum communication system adds a spread spectrum module and a despreading module to the transmitting end and the receiving end of the ordinary digital communication system respectively. The spread spectrum communication system uses the spread spectrum module to spread the signal after channel coding, and then uses the carrier modulation method to send the spread spectrum signal. The receiving end first despreads the received signal, and then demodulates and decodes the signal to restore the baseband signal. Here, the random code used for despreading must be the same as the code type and code rate of the spread spectrum code used during spread spectrum, so the system needs to synchronize the random code.

[0003] The direct sequence spread spectrum system is the most widely used method in spread spectrum communication. The direct sequence spread spectrum system uses a set of random codes to represent information code elements to modulate the carrier. Usually, any modulation method can be selected. The most commonly used modulation method is to add the transmitted information sequence to the pseudo-random sequence modulo 2 to complete the spread spectrum. The sequence after spread spectrum is modulated on the carrier to obtain the transmitted signal. At the receiving end, the same random sequence synchronized with the transmitting end is used to perform modulo 2 addition operation with the received signal to achieve despreading. After signal demodulation, the original signal code of the transmitting end can be restored. Figure 1 Shown is a functional block diagram of a direct sequence spread spectrum system.

[0004] The spread spectrum code of traditional spread spectrum communication uses pseudo-random numbers. At present, with the emergence of quantum computers, algorithm-based pseudo-random numbers face increasing security threats. Moreover, the forward security risk of classical pseudo-random numbers is irreparable. A single decryption may mean that all information within a period of time has been cracked, so the security of the entire system can only be ensured by constantly replacing the master key. The delivery of the master key means establishing a complete management system and a reliable team of personnel, which is extremely costly and has many uncontrollable risk factors in the delivery process. Summary of the invention

[0005] In view of the above-mentioned problems existing in the prior art, the present application proposes a direct sequence spread spectrum communication method and system based on true random numbers, which provides true random numbers for the direct sequence spread spectrum communication system using quantum keys, provides additional information entropy for spread spectrum code generation, increases the unpredictability of the random number sequence, and thus improves the security of the channel.

[0006] One aspect of the present invention relates to a direct sequence spread spectrum communication system based on true random numbers, comprising a transmitter and a receiver, wherein the transmitter is configured to spread a data signal using a spread spectrum code to generate a spread spectrum modulated radio frequency signal, and the receiver is configured to despread the spread spectrum modulated radio frequency signal using the spread spectrum code to obtain the data signal, characterized in that:

[0007] The transmitter is provided with a first quantum key distribution device, and the receiver is provided with a second quantum key distribution device;

[0008] The first quantum key distribution device and the second quantum key distribution device are configured to generate the same quantum key by means of a quantum key distribution process; and

[0009] The spreading code is generated based on the quantum key.

[0010] Furthermore, the transmitter also includes a signal source, a spread spectrum module, a first spread spectrum code generation module, a local oscillator, a modulation module and a transmitting antenna; and the receiver also includes a mixing module, a local oscillator, a despreading module, a second spread spectrum code generation module, a spread spectrum synchronization module, a demodulation module and a receiving antenna.

[0011] Furthermore, the first quantum key distribution device is configured to directly provide the quantum key as a random number to the first spread spectrum code generation module; the second quantum key distribution device is configured to directly provide the quantum key as a random number to the second spread spectrum code generation module.

[0012] Furthermore, the transmitter also includes a first key expansion algorithm module, which is configured to perform an expansion operation on the quantum key using a key expansion algorithm to generate a random number for use in the first spread spectrum code generation module; the receiver also includes a second key expansion algorithm module, which is configured to perform an expansion operation on the quantum key using a key expansion algorithm to generate a random number for use in the second spread spectrum code generation module.

[0013] Preferably, the transmitter also includes a first randomness detection module, which is configured to perform randomness detection on the random number generated by the first key expansion algorithm module; the receiver also includes a second randomness detection module, which is configured to perform randomness detection on the random number generated by the second key expansion algorithm module.

[0014] Further, the first and second spreading code generating modules are configured to generate the spreading code based on the random number;

[0015] The spectrum spreading module is configured to perform multiplication or modulo-two addition processing on the data signal and the spread spectrum code to generate a spread spectrum signal;

[0016] The modulation module is configured to modulate the local carrier signal using the spread spectrum signal to generate the spread spectrum modulated radio frequency signal;

[0017] The mixing module is configured to perform mixing processing on the spread spectrum modulated radio frequency signal;

[0018] The despreading module is configured to perform despreading processing on the spread spectrum modulated RF signal after mixing processing by using the spread spectrum signal;

[0019] The demodulation module is configured to demodulate the despread signal to generate the data signal.

[0020] Furthermore, the receiver may further include a signal amplification module, which is configured to amplify the spread spectrum modulated radio frequency signal before the frequency mixing module.

[0021] Another aspect of the present invention relates to a direct sequence spread spectrum communication method based on true random numbers, which comprises the following steps:

[0022] Distribute the same quantum key in the receiver and transmitter with the help of quantum key distribution process;

[0023] In the transmitter, a spread spectrum code is generated based on the quantum key, a data signal is spread spectrum using the spread spectrum code to generate a spread spectrum signal, and a local carrier signal is modulated using the spread spectrum signal to generate a spread spectrum modulated radio frequency signal;

[0024] In the receiver, the spread spectrum modulated RF signal is mixed, the spread spectrum code is generated based on the quantum key, the spread spectrum modulated RF signal is despread using the spread spectrum code, and the despread signal is demodulated to obtain the data signal.

[0025] Furthermore, in the transmitter, the spread spectrum code is directly generated by using the quantum key, or the spread spectrum code is generated by using a random number generated with the help of the quantum key; and the data signal is multiplied or modulo-2 added using the spread spectrum code to generate the spread spectrum signal; and, in the receiver, the spread spectrum code is directly generated by using the quantum key, or the spread spectrum code is generated by using a random number generated with the help of the quantum key.

[0026] Furthermore, the above direct sequence spread spectrum communication method can be implemented with the help of the direct sequence spread spectrum communication system of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. It is obvious that the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 An example of a direct sequence spread spectrum communication system of the prior art is shown;

[0030] Figure 2 An exemplary embodiment of a direct sequence spread spectrum communication system according to the present invention is schematically shown;

[0031] Figure 3 A further exemplary embodiment of a direct sequence spread spectrum communication system according to the invention is schematically shown. DETAILED DESCRIPTION

[0032] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so as to fully convey the spirit of the present invention to those skilled in the art to which the present invention belongs. Therefore, the present invention is not limited to the embodiments disclosed herein.

[0033] Figure 2 An exemplary embodiment of a direct sequence spread spectrum communication system according to the present invention is shown. On the basis of the existing direct sequence spread spectrum communication system, a quantum key distribution device is used to provide completely consistent true random numbers for the spread spectrum code generation modules in the transmitter and the receiver, and participate in the spread spectrum code generation at both ends of the transmission and reception to improve the security of the channel.

[0034] like Figure 2 As shown, the direct sequence spread spectrum communication system of the present invention may include a transmitter and a receiver.

[0035] The transmitter may include a signal source, a spread spectrum module, a first spread spectrum code generation module, a local oscillator, a modulation module, a transmitting antenna and a first quantum key distribution device.

[0036] The receiver includes a signal amplification module, a frequency mixing module, a local oscillator, a despreading module, a second spread spectrum code generation module, a spread spectrum synchronization module, a demodulation module, a receiving antenna and a second quantum key distribution device.

[0037] The first quantum key distribution device and the second quantum key distribution device are used to generate the same quantum key by means of the quantum key distribution process, which will be used to construct the random number source in the transmitter and the receiver. Since the quantum key has true randomness, the random number source constructed based on the quantum key is a true random number source, and the true random number source implemented in the transmitter and the receiver respectively based on the same quantum key can output completely consistent true random numbers, which can meet the needs of direct sequence spread spectrum communication, making it possible to overcome the problems caused by the use of pseudo-random numbers in the existing direct sequence spread spectrum communication system.

[0038] exist Figure 2 In an exemplary embodiment, the quantum key distribution device is directly used as a random number source. In other words, the quantum key output by the quantum key distribution device is directly provided to the spread spectrum code generation module as a true random number.

[0039] Specifically, in the transmitter, the first quantum key distribution device provides the distributed quantum key as a random number to the first spread spectrum code generation module.

[0040] The first spreading code generating module generates a random spreading code based on a random number.

[0041] The signal source is used to provide a data signal to be transmitted.

[0042] The spread spectrum module multiplies or performs modulo-two addition processing on the data signal and the spread spectrum code to generate a spread spectrum signal with the same rate as the spread spectrum code rate, thereby expanding the frequency band of the data signal.

[0043] A local oscillator generates a local carrier signal.

[0044] The modulation module modulates the local carrier signal using the spread spectrum signal to obtain a spread spectrum modulated radio frequency signal.

[0045] The transmitter transmits the spread spectrum modulated RF signal outward through the transmitting antenna.

[0046] In the receiver, the second quantum key distribution device provides the distributed same quantum key as a random number to the second spread spectrum code generation module.

[0047] The second spreading code generating module generates a random spreading code based on the random number, which is consistent with the spreading code generated by the first spreading code generating module.

[0048] The receiving antenna receives the spread spectrum modulated RF signal transmitted by the transmitter.

[0049] The signal amplification module performs signal amplification processing on the received RF signal, and then performs mixing processing on the RF signal with the help of the local oscillator and the mixing module.

[0050] The despreading module despreads the pre-processed radio frequency signal using a spreading code (which is consistent with the spreading code used for spreading).

[0051] The despread signal is then demodulated by the demodulation module to obtain the data signal to be transmitted.

[0052] In order to ensure the time synchronization of the output of the spread spectrum code in the receiver and the transmitter, a spread spectrum synchronization module is also provided in the receiver to enable the receiver and the transmitter to use the same despreading code at the same time.

[0053] Next we will continue to combine Figure 2 The direct sequence spread spectrum communication method according to the present invention is described in detail in order to further understand the working principle of the present invention.

[0054] In the direct sequence spread spectrum communication method of the present invention, the same quantum key is distributed in the receiver and the transmitter by means of a quantum key distribution process. For example, the quantum key distribution process can be implemented by means of a first and a second quantum key distribution device.

[0055] In the transmitter, a quantum key is used to generate a random number, a spread spectrum code is generated based on the random number, and the spread spectrum code is used to multiply or modulo-two add the data signal provided by the signal source to obtain a spread spectrum signal.

[0056] Then, the local carrier signal provided by the local oscillator is modulated by the spread spectrum signal to generate a spread spectrum modulated radio frequency signal, which is then transmitted outwardly via the transmitting antenna.

[0057] In the receiver, the RF signal is received and pre-processed such as amplification and mixing.

[0058] A quantum key is used to generate a random number, a spread spectrum code is generated based on the random number, and the pre-processed radio frequency signal is despread according to the spread spectrum code to obtain an intermediate frequency modulated signal.

[0059] Finally, the intermediate frequency modulated signal is demodulated to obtain the data signal to be transmitted.

[0060] Figure 3 A further exemplary embodiment of a direct sequence spread spectrum communication system according to the present invention is shown.

[0061] As shown in the figure, in this exemplary embodiment, the transmitter may include a first key expansion algorithm module and a first randomness detection module in addition to a signal source, a spread spectrum module, a first spread spectrum code generation module, a local oscillator, a modulation module, a transmitting antenna and a first quantum key distribution device.

[0062] In addition to the signal amplification module, the mixing module, the local oscillator, the despreading module, the second spread spectrum code generation module, the spread spectrum synchronization module, the demodulation module, the receiving antenna and the second quantum key distribution device, the receiver can also include a second key expansion algorithm module and a second randomness detection module.

[0063] Therefore, unlike Figure 2 ,exist Figure 3 In the illustrated embodiment, a random number source is formed by a quantum key distribution device, a key expansion algorithm module, and a randomness detection module.

[0064] Specifically, the quantum key distribution device provides the quantum key generated therein as a seed source to the key expansion algorithm module.

[0065] The key expansion algorithm module uses the key expansion algorithm to perform expansion operations on the quantum key to generate new random numbers.

[0066] The randomness detection module performs randomness detection on the new random numbers generated by the extended operation to ensure that they have good random number statistical characteristics.

[0067] The extended random number detected to have good random number statistical characteristics is output to the frequency modulation sequence generation module.

[0068] Since the signal source, the spread spectrum module, the first spread spectrum code generation module, the local oscillator, the modulation module and the transmitting antenna in the transmitter, and the signal amplification module, the mixing module, the local oscillator, the despreading module, the second spread spectrum code generation module, the spread spectrum synchronization module, the demodulation module and the receiving antenna in the receiver are the same as the above Figure 2 The embodiments described in the present invention are the same as those described in the embodiments of the present invention, so they will not be repeated here.

[0069] In the present invention, it is proposed for the first time to distribute the same quantum key at the transmitter and receiver of the direct sequence spread spectrum communication system by means of quantum key distribution technology, so that it is possible to provide completely consistent true random numbers at both communicating parties. The true random numbers generated by quantum key distribution provide additional information entropy for the spread spectrum code generation of the direct sequence spread spectrum communication system, which can effectively solve the security problems caused by the use of pseudo-random numbers in the current direct sequence spread spectrum communication system. In addition, it is further proposed to use the key expansion algorithm to realize the true random number source, improve the utilization efficiency of the quantum key, and reduce the performance requirements for quantum key distribution. At the same time, the random number detection technology is used to ensure the randomness of the spread spectrum code, thereby improving the system efficiency of the direct sequence spread spectrum communication system while ensuring the security of the system.

[0070] Although the present invention has been described above through specific embodiments in conjunction with the accompanying drawings, those skilled in the art will readily recognize that the above embodiments are merely exemplary and are used to illustrate the principles of the present invention, and do not limit the scope of the present invention. Those skilled in the art may make various combinations, modifications and equivalent substitutions to the above embodiments without departing from the spirit and scope of the present invention.

Claims

1. A direct sequence spread spectrum communication system based on true random numbers, comprising a transmitter and a receiver, wherein: The transmitter is configured to spread the data signal using a spread spectrum code to generate a spread spectrum modulated radio frequency signal, and the receiver is configured to despread the spread spectrum modulated radio frequency signal using the spread spectrum code to obtain the data signal, characterized in that: The transmitter is provided with a first quantum key distribution device, and the receiver is provided with a second quantum key distribution device; The first quantum key distribution device and the second quantum key distribution device are configured to generate the same quantum key by means of a quantum key distribution process; and The spread spectrum code is generated based on the quantum key; The transmitter also includes a signal source, a spread spectrum module, a first spread spectrum code generation module, a local oscillator, a modulation module and a transmitting antenna; and, The receiver also includes a frequency mixing module, a local oscillator, a despreading module, a second spread spectrum code generating module, a spread spectrum synchronization module, a demodulation module and a receiving antenna; The transmitter further comprises a first key expansion algorithm module, which is configured to perform an expansion operation on the quantum key using a key expansion algorithm to generate a random number for use in the first spread spectrum code generation module; The receiver further comprises a second key expansion algorithm module, which is configured to perform an expansion operation on the quantum key using a key expansion algorithm to generate a random number for use in the second spread spectrum code generation module; The transmitter further comprises a first randomness detection module, which is configured to perform randomness detection on the random number generated by the first key expansion algorithm module; The receiver also includes a second randomness detection module, which is configured to perform randomness detection on the random number generated by the second key expansion algorithm module.

2. The direct sequence spread spectrum communication system as claimed in claim 1, wherein: The first and second spreading code generation modules are configured to generate the spreading code based on the random number; The spectrum spreading module is configured to perform multiplication or modulo-two addition processing on the data signal and the spread spectrum code to generate a spread spectrum signal; The modulation module is configured to modulate the local carrier signal using the spread spectrum signal to generate the spread spectrum modulated radio frequency signal; The mixing module is configured to perform mixing processing on the spread spectrum modulated radio frequency signal; The despreading module is configured to perform despreading processing on the spread spectrum modulated RF signal after mixing processing by using the spread spectrum signal; The demodulation module is configured to demodulate the despread signal to generate the data signal.

3. The direct sequence spread spectrum communication system as claimed in claim 2, wherein: The receiver further comprises a signal amplifying module, which is configured to amplify the spread spectrum modulated radio frequency signal before the frequency mixing module.

4. A direct sequence spread spectrum communication method based on true random numbers, comprising the following steps: Distribute the same quantum key in the receiver and transmitter with the help of quantum key distribution process; In the transmitter, a spread spectrum code is generated based on the quantum key, a data signal is spread spectrum using the spread spectrum code to generate a spread spectrum signal, and a local carrier signal is modulated using the spread spectrum signal to generate a spread spectrum modulated radio frequency signal; In the receiver, mixing processing is performed on the spread spectrum modulated radio frequency signal, the spread spectrum code is generated based on the quantum key, despreading processing is performed on the spread spectrum modulated radio frequency signal using the spread spectrum code, and the despread signal is demodulated to obtain the data signal; In the transmitter, the spread spectrum code is generated by using a random number generated by performing an expansion operation on the quantum key with the help of a key expansion algorithm; In the receiver, the spread spectrum code is generated by using a random number generated by performing an expansion operation on the quantum key with the help of a key expansion algorithm.

5. The direct sequence spread spectrum communication method as claimed in claim 4, wherein: In the transmitter, the data signal is multiplied or modulo-two added using the spread spectrum code to generate the spread spectrum signal.

6. The direct sequence spread spectrum communication method according to claim 5, which is implemented by means of the direct sequence spread spectrum communication system according to any one of claims 1 to 3.

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