阅读说明：本技术 一种5g网络中随机数加密的多址无源光网络 (Random number encrypted multi-address passive optical network in 5G network ) 是由 李齐良 肖涛 白皓若 胡淼 唐向宏 曾然 于 2021-06-21 设计创作，主要内容包括：本发明5G网络中随机数加密的多址无源光网络,包括：发送端包括j路结构,每路中,信号发生器与映射器相连,映射器连接两个加法器,两加法器间连接随机数发生器,加法器通过乘法器后连接第二加法器,第二加法器通过串并变换器的N个端口连接IFFT变换器,IFFT变换器j×N个端口连接并串变换器,并串变换器依次通过滤波器、循环前缀导入器、直流偏置器、光电调制器连接EDFA；EDFA依次通过光电检测器、直流偏置器、去导频循环前缀器、滤波器连接串并变换器,串并变换器j×N个端口连接FFT变换器,FFT变换器连接j路结构,每路中,FFT变换器N个端口连接并串变换器,并串变换器连接两乘法器,乘法器依次通过积分器、减法器后连接映射器,两减法器间连接随机数发生器。(The invention relates to a random number encrypted multiple access passive optical network in a 5G network, which comprises: the transmitting end comprises a j-path structure, in each path, a signal generator is connected with a mapper, the mapper is connected with two adders, a random number generator is connected between the two adders, the adders are connected with a second adder after passing through the multipliers, the second adder is connected with an IFFT converter through N ports of a serial-parallel converter, the IFFT converter is connected with a parallel-serial converter through j multiplied by N ports, and the parallel-serial converter is connected with an EDFA through a filter, a cyclic prefix importer, a direct current biaser and a photoelectric modulator in sequence; the EDFA is connected with the series-parallel converter through the photoelectric detector, the direct current biaser, the pilot frequency removing cyclic prefix device and the filter in sequence, j multiplied by N ports of the series-parallel converter are connected with the FFT converter, the FFT converter is connected with a j-path structure, N ports of the FFT converter are connected with the parallel-serial converter in each path, the parallel-serial converter is connected with two multipliers, the multipliers are connected with the mapper after passing through the integrator and the subtracter in sequence, and the random number generator is connected between the two subtracters.)

1. A random number encrypted multiple access passive optical network in a 5G network, comprising:

the sending end comprises j paths of structures, and each path of structure is as follows: the signal generator is connected with a first mapper, the first mapper is connected with two first adders, a first random number generator is connected between the two first adders, each first adder is connected with a second adder after passing through a first multiplier, the second adder is connected with a first serial-parallel converter, the first serial-parallel converter is connected to an IFFT converter through N ports, the JN output ports of the IFFT converter are connected with first parallel-serial converters, the first parallel-serial converters are connected with an optoelectronic modulator after passing through a first filter, a cyclic prefix importer and a first direct current biaser in sequence, and the optoelectronic modulator converts electric signals into optical signals and connects the optical signals to an erbium-doped optical fiber amplifier of a receiving end through an optical fiber;

the erbium-doped fiber amplifier at the receiving end is connected with the second serial-parallel converter through the photoelectric detector, the second direct current biaser, the pilot frequency removing cyclic prefix device and the second filter in sequence, j multiplied by N output ports of the second serial-parallel converter are connected with the FFT converter, the FFT converter is connected with j paths of structures, and each path of structure is as follows: n ports of the FFT converter are connected to a second parallel-serial converter, the second parallel-serial converter is connected with two second multipliers, the two multipliers are respectively connected with a second mapper after passing through an integrator and a subtracter in sequence, and a second random number generator is connected between the two subtracters.

2. The multiple access passive optical network for random number encryption in a 5G network according to claim 1, wherein the first random number generator is generated by quantization from the chaotic sequence generated by the corresponding chaotic generator, and the second random number generator is generated by quantization from the chaotic sequence generated by the corresponding chaotic generator; the chaotic generator of the first random number generator is synchronized with the chaotic generator of the second random number generator.

3. The multi-access PON of claim 2, wherein at the transmitting end, the j-path signal generator generates the information sequence mj and transmits the information sequence mj to the corresponding mapper, and the various bit combinations are mapped into x according to the Gray code mapping rule_j,y_jTwo symbol data.

4. The multi-access passive optical network for random number encryption in 5G network as claimed in claim 3, wherein at the transmitting end, the random numbers generated by the j paths of the first random number generators are respectively associated with the symbol x by two first adders_j,y_jAdding to obtain encrypted new symbol x'_j,y′_jAnd the pilot frequency symbols are added to realize the encryption of the information.

5. The multi-access passive optical network with random number encryption in 5G network as claimed in claim 4, wherein at the transmitting end, the symbol x'_j,y′_jThe divided edges are multiplied by cos ω t and-sin ω t and then added by a second adder to generate a complex symbol x'_j+iy′_jAnd completing the encrypted quadrature amplitude modulation.

6. The multiple access passive optical network for random number encryption in a 5G network as claimed in claim 5, wherein at the transmitting end, the complex symbol sequence converts the serial symbol sequence into a parallel symbol stream through the first serial-to-parallel converter; and performing inverse fast Fourier transform by using an IFFT transformer to transform the symbols of the frequency domain to the time domain.

7. The multi-access passive optical network for random number encryption in 5G network as claimed in claim 6, wherein at the transmitting end, the time domain symbol outputted from IFFT converter is converted into serial signal by the first parallel-to-serial converter, the negative power part is cut off by the first DC bias device through the first filter and the cyclic prefix leading-in device, and the signal is converted into optical signal through the electro-optical modulator and transmitted in the optical fiber.

8. The multiple access passive optical network for random number encryption in 5G network as claimed in any one of claims 4-7, wherein at the receiving end, the erbium doped fiber amplifier amplifies the information, then the photodetector is used to change the optical signal into electrical signal, the second DC biaser is used to recover the negative power portion, the second DC biaser is used to filter the signal through the pilot-free cyclic prefix device and the second filter, and the second serial-to-parallel converter is used to convert the serial symbols into parallel symbols.

9. The PON of claim 8, wherein at a receiving end, the frequency domain symbols output by the FFT converter are converted into j serial symbols through j second parallel-to-serial converters, each serial symbol has N symbols, each serial symbol is divided into two paths, each symbol is multiplied by cos ω t and-sin ω t, and the integration is performed in one period by using a corresponding integrator, and j paths obtain j sets of x'_j,y′_jAnd then subtracts the pilot symbols.

10. The multiple access passive optical network for random number encryption in 5G network as claimed in claim 9, wherein at the receiving end, the symbol x'_j,y′_jSubtracting the random number generated by the second random number generator by the subtracter to obtain x_j,y_j(ii) a X is mapped by a second mapper_j,y_jThe corresponding original information mj is restored.

Technical Field

The invention belongs to the technical field of secret communication and information security in a 5G network, and particularly relates to a random number encrypted multiple-access passive optical network in the 5G network.

Background

The 5G network makes full use of frequency band resources, and the Orthogonal Frequency Division Multiplexing (OFDM) used by the 5G network is a technology which utilizes mutually orthogonal multiple subcarriers, firstly carries out quadrature amplitude modulation (M-QAM) or phase shift keying (M-PSK) modulation on information, then modulates the information on each subcarrier, maps the signal into a complex symbol, changes the signal into a time domain signal by utilizing Inverse Fast Fourier Transform (IFFT), and adds pilot frequency and cyclic prefix. At a receiving end, pilot frequency and cyclic prefix are removed, received information is converted into frequency domain information by using Fast Fourier Transform (FFT), and then original information is demodulated by using coherent demodulation and mapping relation. Compared with the traditional FDM (frequency division multiplexing), the OFDM can fully utilize frequency resources and eliminate intersymbol interference caused by multipath effect. However, in the prior art, the communication security problem still exists.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a random number encrypted multiple access passive optical network in a 5G network. The innovation of the invention is that chaos is used to generate random numbers, the random numbers and symbols generated by QAM modulation are added, so as to encrypt the symbols generated by QAM, then the symbols are modulated on each subcarrier, and the signals are changed into time domain signals by Inverse Fast Fourier Transform (IFFT), so that an attacker can not directly recover the information; at a receiving end, pilot frequency and cyclic prefix are removed, received information is converted into frequency domain information by using Fast Fourier Transform (FFT), then coherent demodulation is used for recovering encrypted symbols, random numbers are subtracted, symbols generated by QAM modulation and mapping relations are recovered, and transmitted information is demodulated.

In order to achieve the purpose of the invention, the invention adopts the following technical scheme:

a random number encrypted multiple access passive optical network in a 5G network, comprising:

the sending end comprises j paths of structures, and each path of structure is as follows: the signal generator is connected with a first mapper, the first mapper is connected with two first adders, a first random number generator is connected between the two first adders, each first adder is connected with a second adder after passing through a first multiplier, the second adder is connected with a first serial-parallel converter, the first serial-parallel converter is connected to an IFFT converter through N ports, the JN output ports of the IFFT converter are connected with first parallel-serial converters, the first parallel-serial converters are connected with an optoelectronic modulator after passing through a first filter, a cyclic prefix importer and a first direct current biaser in sequence, and the optoelectronic modulator converts electric signals into optical signals and connects the optical signals to an erbium-doped optical fiber amplifier of a receiving end through an optical fiber;

the erbium-doped fiber amplifier at the receiving end is connected with the second serial-parallel converter through the photoelectric detector, the second direct current biaser, the pilot frequency removing cyclic prefix device and the second filter in sequence, j multiplied by N output ports of the second serial-parallel converter are connected with the FFT converter, the FFT converter is connected with j paths of structures, and each path of structure is as follows: n ports of the FFT converter are connected to a second parallel-serial converter, the second parallel-serial converter is connected with two second multipliers, the two multipliers are respectively connected with a second mapper after passing through an integrator and a subtracter in sequence, and a second random number generator is connected between the two subtracters.

Preferably, the random number generators are generated by quantification of the chaotic sequences generated by the corresponding chaotic generators, and the chaotic generator in the first random number generator is synchronized with the chaotic generator in the second random number generator.

As the preferred scheme, at the transmitting end, a j-path signal generator generates an information sequence mj and transmits the information sequence mj to a corresponding mapper, and various bit combinations are mapped into x according to the mapping rule of Gray codes_j,y_jTwo symbol data.

Preferably, at the transmitting end, the random number generated by the j-path first random number generator passes through two second random number generatorsAn adder respectively with the symbol x_j,y_jAdding to obtain encrypted new symbol x'_j,y′_jAnd realizing the encryption of the information.

Preferably, at the transmitting end, the output symbol x'_j,y′_jThe divided edges are multiplied by cos ω t and-sin ω t and then added by a second adder to generate a complex symbol x'_j+iy′_jThe encrypted Quadrature Amplitude Modulation (QAM) is completed, plus a pilot training sequence. The transmitting end thus converts the transmitted digital signal into a mapping of subcarrier amplitudes.

Preferably, at the transmitting end, the formed complex symbol sequence is converted into a parallel symbol stream by a first serial-to-parallel converter; and performing inverse fast Fourier transform by using an IFFT transformer to transform the symbols of the frequency domain to the time domain. Every N serial-to-parallel converted symbols are modulated by a different subcarrier.

Preferably, at the transmitting end, the time domain symbol output by the IFFT converter is converted into a serial signal by a first parallel-to-serial converter, the negative power portion is cut off by a first dc bias device through a first filter and a cyclic prefix lead-in device, and the serial signal is converted into an optical signal by an electro-optical modulator and transmitted through an optical fiber.

Preferably, at the receiving end, after the first EDFA amplifies the information, the photodetector converts the optical signal into an electrical signal, the second dc biaser restores the negative power portion, the pilot-removed cyclic prefix device passes through the negative power portion, the second filter performs filtering, and the second serial-to-parallel converter converts the serial symbols into parallel symbols.

Preferably, at the receiving end, the frequency domain symbols output by the FFT converter are converted into j paths of serial symbols (N symbols per path) by j second parallel-to-serial converters. Each path of serial symbols is divided into two paths, multiplied by cos ω t and-sin ω t respectively, and integrated in one period by using a corresponding integrator, and the first path obtains x'₁,y′₁(ii) a …, respectively; line j gives x'_j,y′_jAnd then subtracts the pilot training sequence.

Preferably, at the receiving end, symbol x'_j,y′_jSubtracting the random number generated by the second random number generator by the subtracter to obtain x_j,y_j。

Preferably, at the receiving end, x is mapped by the second mapper_j,y_jThe corresponding original information mj is restored.

The invention relates to a principle and a process of a random number encrypted multiple access passive optical network in a 5G network, wherein the principle and the process are as follows: the random number generators are generated by quantification of chaotic sequences generated by corresponding chaotic generators, the chaotic generator in the 1 st random number generator is synchronous with the chaotic generator of the j +1 th random number generator, …, and the chaotic generator of the j th random number generator is synchronous with the chaotic generator of the 2j th random number generator. At the transmitting end, the 1 st signal generator generates an information sequence m1 to be transmitted to the 1 st mapper, and various bit combinations are mapped into x according to the mapping rule of the Gray code₁,y₁Two symbol data …, the j information generator generates information sequence mj and transmits it to the j mapper to map various bit combinations to x according to the mapping rule of Gray code_j,y_jTwo symbol data. The random number generated by the 1 st random number generator is respectively added with the symbol x by the first adder and the second adder₁,y₁Adding to obtain encrypted new symbol x'₁,y′₁…, the random number generated by the jth random number generator is added to the symbol x by the 2j-1 and 2j adders, respectively_j,y_jAdding to obtain encrypted new symbol x'_j,y′_j. Thus, the encryption of the information is realized. Then the 1 st and 2 nd adders output symbols x'₁,y′₁The divided sides are multiplied by cos ω t and sin ω t and then added by a 2j +1 adder to generate a complex symbol x'₁+iy′₁Adding pilot training symbols, …, the 2j-1 and 2j adders outputting symbols x'_j,y′_jThe divided sides are multiplied by cos ω t and-sin ω t and then added by a 3j adder to generate a complex symbol x'_j+iy′_jAdding pilot training symbols, thus completing the encrypted Quadrature Amplitude Modulation (QAM) and encryption and derivationFrequency adding, so that the transmitting end converts the transmitted digital signal into a mapping of subcarrier amplitudes.

Meanwhile, the complex symbol sequence formed by the 2j +1 st adder is converted into a parallel symbol stream by the 1 st serial-parallel converter. The 2j +2 th adder forms a symbol sequence, the 2 nd serial-parallel converter converts the serial symbol sequence into a parallel symbol stream, …, the 3j th adder forms a symbol sequence, and the j th serial-parallel converter converts the serial symbol sequence into a parallel symbol stream. And performing inverse fast Fourier transform by using an IFFT transformer to transform the spectrum expression of the data to a time domain. Every N serial-to-parallel converted symbols are modulated by a different subcarrier. The time domain symbol output by the IFFT converter is converted into a serial signal through a1 st parallel-serial converter, a1 st filter and a cyclic prefix leading-in device are used for cutting off a negative power part by a1 st direct current biaser, and the serial signal is converted into an optical signal through an optoelectronic modulator and transmitted in an optical fiber.

After optical fiber transmission, loss is compensated by an EDFA at a receiving end, information is amplified, an optical signal is converted into an electric signal by using a photoelectric detector, a negative power part is restored by using a 2 nd direct current biaser, filtering is carried out by using a 2 nd filter through a cyclic prefix removing device, and a serial symbol is converted into a parallel symbol by using a j +1 th serial-parallel converter. The frequency domain symbols output by the FFT transformer are converted into j paths of serial symbols (N symbols per path) by j parallel-to-serial converters. Each path of serial symbols is divided into two paths, multiplied by cos ω t and-sin ω t respectively, and integrated in one period by using a corresponding integrator, and the first path obtains x'₁,y′₁The training pilot is subtracted. … are provided. Line j gives x'_j,y′_jThe training pilot is subtracted. First road symbol x'₁,y′₁Subtracting the random number generated by the (j +1) th random number generator from the 1 st subtracter to obtain x₁,y₁…, jth symbol x'_j,y′_jSubtracting the random number generated by the 2j random number generator by a j subtracter to obtain x_j,y_j. The first path passes x through the j +1 th mapper₁,y₁Restoring original informationm1, …, jth path x is mapped by 2j mapper_j,y_jThe corresponding original information mj is restored.

Compared with the prior art, the invention has the beneficial effects that:

the invention completes the safety communication of the multi-address passive optical network encrypted by random number in the 5G network, and the safety is as follows: during decoding, chaos must be synchronized to generate the same random number, and the chaos is sensitive to circuit parameters and initial conditions, so that the communication safety is enhanced.

Drawings

Fig. 1 is a block diagram of a multiple access passive optical network security communication system with random number encryption in a 5G network according to an embodiment of the present invention.

Fig. 2 is a constellation diagram before encryption according to an embodiment of the present invention.

FIG. 3 is a constellation diagram after encryption according to an embodiment of the present invention; it is shown that the transmitted information cannot be recovered by the encrypted constellation.

Fig. 4 shows the relationship between the bit error rate and the signal-to-noise ratio of the OFDM encryption communication system according to the embodiment of the present invention.

Fig. 5(a) shows the original signal transmitted in the first path, and fig. 5(b) shows the demodulated signal.

Wherein:

1 st signal generator 1-1, … j signal generator 1-j;

1 st mapper 2-1, …, jth mapper 2-j;

the 1 st adder 18-1, the 2 nd adder 18-2, the … the 18 th- (2j-1) adder 18- (2j-1), the 2j adder 18-2 j; the 18- (2j +1) th adder 18- (2j +1) and the 18-3j th adder 18-3 j;

1 st random number generator 3-1, …, jth random number generator 3-j;

a1 st multiplier 4-1, a 2 nd multiplier 4-2, …, a 4 th- (2j-1) multiplier 4- (2j-1) and a 2j multiplier 4-2 j;

a1 st serial-parallel converter 5-1, a 2 nd serial-parallel converter 5-2, …, a jth serial-parallel converter 5-j, a jth +1 serial-parallel converter 5- (j + 1);

an IFFT converter 6;

a1 st parallel-to-serial converter 7-1, a 2 nd parallel-to-serial converter 7-2, …, a j +1 th parallel-to-serial converter 7- (j + 1);

a1 st filter 8-1, a 2 nd filter 8-2;

a cyclic prefix importer 9;

a1 st direct current biaser 10-1 and a 2 nd direct current biaser 10-2;

an electro-optical modulator 11;

an EDFA (erbium-doped fiber amplifier) 12;

a photodetector 13;

a pilot-removing cyclic prefix device 14;

an FFT converter 15;

the 2j +1 th multiplier 4- (2j +1), …, the 4- (4j-1) th multiplier 4- (4j-1) and the 4j multiplier 4-4 j;

1 st integrator 16-1, 2 nd integrators 16-2, …, 2j integrator 16-2 j;

a j +1 th mapper 2- (j +1), a j +2 th mapper 2- (j +2), …, a 2j th mapper 2-2 j;

a j +1 th random number generator 3- (j +1), a j +2 th random number generator 3- (j +2), …, a 2j random number generator 3-2 j;

a j +1 th chaotic generator 1- (j +1), a j +2 th chaotic generator 1- (j +2), … and a 2j chaotic generator 1-2 j;

the 1 st subtracter 17-1, the 2 nd subtracters 17-2, …, the 17- (2j-1) th subtracter 17- (2j-1), the 2j subtracter 17-2 j.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention, the following description will explain the embodiments of the present invention with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

The embodiment of the invention relates to a random number encrypted multiple access passive optical network in a 5G network, which comprises a sending end and a receiving end, wherein the sending end and the receiving end are connected through an optical fiber.

The transmitting end specifically comprises a1 st signal generator, an … th signal generator, a1 st mapper, an … th mapper, a1 st random number generator, … a jth random number generator, a1 st adder, …, a 2j adder, a 2j +1 st adder, …, a 3j adder, a1 st multiplier, a 2 nd multiplier, …, a 2j multiplier, a1 st serial-to-parallel converter, … a jth serial-to-parallel converter, an IFFT converter, a1 st parallel-to-serial converter, a1 st filter, a cyclic prefix importer, a1 st DC biaser and an optoelectronic modulator.

The receiving end comprises an EDFA (erbium doped fiber amplifier), a photoelectric detector, a 2 nd filter, a 2 nd DC biaser, a pilot-removing cyclic prefix device, a j +1 th serial-parallel converter, an FFT converter, a 2 nd parallel-serial converter, …, a 2j +1 th parallel-serial converter, a 2j +1 th multiplier, …, a 4j multiplier, a1 st integrator, a 2 nd integrator, …, a 2j integrator, a1 st subtracter, a 2 nd subtracter, …, a 2j subtracter, a j +1 th random number generator, …, a 2j random number generator, a j +1 mapper, … and a 2j mapper.

The receiving end is connected with the transmitting end through an optical fiber.

The random number generator is generated by the chaos sequence generated by the corresponding chaos generator through quantification, the chaos generator in the 1 st random number generator is synchronous with the chaos generator of the j +1 th random number generator, …, and the chaos generator of the j th random number generator is synchronous with the chaos generator of the 2j th random number generator. At the transmitting end, the 1 st signal generator generates an information sequence m1 to be transmitted to the 1 st mapper, and various bit combinations are mapped into x according to the mapping rule of the Gray code₁,y₁Two symbol data …, the j information generator generates information sequence mj to be transmitted to the j mapper, and various bit combinations are mapped into x according to the mapping rule of Gray code_j,y_jTwo symbol data. The 1 st random number generator generates random numbers which are respectively added with the symbol x by the 1 st adder and the 2 nd adder₁,y₁Adding to obtain encrypted new symbol x'₁,y′₁…, the random number generated by the jth random number generator is added to the symbol x by the 2j-1 and 2j adders, respectively_j,y_jAdding to obtain encrypted new symbol x'_j,y′_j. Thus, the encryption of the information is realized. Then the 1 st and 2 nd adders output symbols x'₁,y′₁The divided sides are multiplied by cos ω t and sin ω t and then added by a 2j +1 adder to generate a complex symbol x'₁+iy′₁Adding pilot sequence, …, the 2j-1 and 2j adders outputting symbols x'_j,y′_jThe divided sides are multiplied by cos ω t and-sin ω t and then added by a 3j adder to generate a complex symbol x'_j+iy′_jAnd adding a pilot sequence, thus completing encrypted Quadrature Amplitude Modulation (QAM) and pilot introduction, so that a transmitting end converts a transmitted digital signal into a mapping of subcarrier amplitude. Here, the 2j +1 th adder forms a complex symbol sequence, and the serial symbol sequence is converted into a parallel symbol stream by a first serial-to-parallel converter. The 2j +2 th adder converts the serial symbol sequence into a parallel symbol stream … through a second serial-to-parallel converter, and the 3j adder converts the serial symbol sequence into a parallel symbol stream through a j serial-to-parallel converter. And performing inverse fast Fourier transform by using an IFFT transformer to transform the frequency domain symbols onto a time domain. Every N serial-to-parallel converted symbols are modulated by a different subcarrier. The time domain symbol output by the IFFT converter is converted into a serial signal through a1 st parallel-serial converter, a1 st filter and a cyclic prefix leading-in device are used for cutting off a negative power part by a 2 nd direct current biaser, and the serial signal is converted into an optical signal through an optoelectronic modulator and transmitted in an optical fiber.

After the signal is transmitted by the optical fiber, the loss is compensated by the EDFA at the receiving end, the information is amplified, the photoelectric detector is used for converting the optical signal into an electric signal, the negative power part is restored by the 2 nd direct current biaser, the circulating prefix removing device is used for filtering by the 2 nd filter, and the serial symbol is converted into the parallel symbol by the j +1 th serial-parallel converter. The frequency domain symbols output by the FFT converter are converted into j paths of serial symbols (N symbols in each path) through a j parallel-to-serial converter. Each path of serial symbols is divided into two paths, multiplied by cos ω t and-sin ω t, respectively, and integrated within one period by a corresponding integrator. The first path is x'₁,y′₁Subtracting the pilot training symbol; …, respectively; line j gives x'_j,y′_jAnd then subtracts the pilot training symbols. First road symbol x'₁,y′₁Subtracting the random number generated by the j +1 th random number generator by the first subtracter to obtain x₁,y₁…, jth symbol x'_j,y′_jSubtracting the random number generated by the 2j random number generator by a j-th subtracter to obtain x_j,y_j. The first path passes x through the j +1 th mapper₁,y₁Original information m1, … is restored, the jth path x is mapped by a 2j mapper_j,y_jThe corresponding original information mj is restored. Thus, the secure communication of the 5G-based passive optical network encryption and decryption is completed.

As shown in fig. 1, the specific connection relationship of the multiple access passive optical network with random number encryption in the 5G network of this embodiment is as follows:

the transmitting end comprises a1 st signal generator 1-1, … th j signal generator 1-j, a1 st mapper 2-1, …, a j mapper 2-j, a1 st random number generator 3-1, …, a j random number generator 3-j, a1 st adder 18-1, a second adder 18-2, …, a 2j adder 18-2j, a 2j +1 st adder 18- (2j +1), a 3j adder 18-3j, a1 st multiplier 4-1, a 2 nd multiplier 4-2, …, a 2j multiplier 4-2j, a1 st serial-parallel converter 5-1, …, a j serial-parallel converter 5-j, an IFFT converter 6, a1 st parallel-serial converter 7-1, a1 st filter 8-1, a cyclic prefix importer 9, A1 st DC biaser 10-1 and an electro-optic modulator 11.

On the transmitting side, the right port of the 1 st signal transmitter 1-1 is connected to the left port of the 1 st mapper 2-1, and the right first and second ports of the 1 st mapper 2-1 are connected to the left two ports of the 1 st adder 18-1 and the 2 nd adder 18-2, respectively. The lower port of the 1 st adder 18-1 is connected with the upper port of the 1 st random number generator 3-1, and the upper port of the 2 nd adder 18-2 is connected with the lower port of the 1 st random number generator 3-1. The right port of the 1 st adder 18-1 is connected with the left port of the 1 st multiplier 4-1, the right port of the 2 nd adder 18-2 is connected with the left port of the 2 nd multiplier 4-2, the right port of the 1 st multiplier 4-1 is connected with the upper port of the 2j +1 st adder 18- (2j +1), and the right port of the 2 nd multiplier 4-2 is connected with the lower port of the 2j +1 st adder 18- (2j + 1). The right port of the 2j +1 st adder 18- (2j +1) is connected with the left port of the 1 st serial-parallel converter 5-1, …, the right port of the j signal transmitter 1-j is connected with the left port of the j mapper 2-j, and the first and second ports on the right side of the j mapper 2-j are respectively connected with the 2j-1 st adder 18- (2j-1) and the two ports on the left side of the 2j adder 18-2 j. The lower port of the 2j-1 adder 18- (2j-1) is connected with the upper port of the j random number generator 3-j, the upper port of the 2j adder 18-2j is connected with the lower port of the j random number generator 3-j, the right port of the 2j-1 adder 18- (2j-1) is connected with the left port of the 2j-1 multiplier 4- (2j-1), the right port of the 2j adder 18-2j is connected with the left port of the 2j multiplier 4-2j, the right port of the 2j-1 multiplier 4- (2j-1) is connected with the upper port of the 3j adder, and the right port of the 2j multiplier 4-2j is connected with the lower port of the 3j adder 18+3 j. The 3 j-th adder 18+3j has its right port connected to the left port of the j-th serial-to-parallel converter 5-j. The N parallel symbols are divided by the 1 st serial-to-parallel converter 5-1, and the N ports on the right side of the 1 st serial-to-parallel converter 5-1 are connected to the N ports on the left side of the IFFT transformer 6.… are provided. Is divided into N parallel symbols by a jth serial-parallel converter 5-j, and N ports on the right side of the jth serial-parallel converter 5-j are connected to N ports on the left side of an IFFT converter 6. The number of ports on the left and right sides of the IFFT transformer 6 is j × N.

The right j × N ports of the IFFT converter 6 are connected to the left j × N ports of the 1 st parallel-to-serial converter 7-1, the 1 st parallel-to-serial converter 7-1 converts the parallel sequence into a serial sequence, the right port of the 1 st parallel-to-serial converter 7-1 is connected to the left port of the 1 st filter 8-1, the right port of the 1 st filter 8-1 is connected to the left port of the pilot and cyclic prefix importer 9, the right port of the pilot and cyclic prefix importer 9 is connected to the left port of the 1 st dc offset device 10-1 to cut out negative symbols, the right port of the 1 st dc offset device 10-1 is connected to the left port of the electro-optical modulator 11, and the electro-optical modulator 11 converts the electrical signal into an optical signal.

The optical signal is connected by fiber to the upper port of EDFA12 at the receiving end.

The receiving end comprises an EDFA (erbium-doped fiber amplifier) 12, a photoelectric detector 13, a 2 nd direct current biaser 10-2, a pilot frequency removing cyclic prefix device 14, a 2 nd filter 8-2, a j +1 th serial-parallel converter 5- (j +1), an FFT converter 15, a 2 nd parallel-serial converter 7-2, …, a j +1 th parallel-serial converter 7- (j +1), a 2j +1 th multiplier 4- (2j +1), …, a 4 th multiplier 4-4j, a1 st integrator 16-1, a 2 nd integrator 16-2, …, a 2j integrator 16-2j, a1 st subtracter 17-1, …, a 2j subtracter 17-2j, a j +1 th random number generator 3- (j +1), …, a 2j random number generator 3-2j, a j +1 th mapper 2- (j +1), a pilot frequency removing cyclic prefix device 14, a 2 nd filter 8-2, a j +1 th serial-parallel converter 5- (j +1), an FFT converter 15, a 2 nd parallel-serial-2 nd parallel-serial converter 7-2 th multiplier 4-4j, a 1-th integrator 16-1, a 1-th integrator 16-2-th integrator, a 2-integrator, a 2-2 j-2 j-2 j-2 j-2 j-2 j-2-j-2 j-2 j-2-j-2-random number-2-1-2-, The j +2 th mapper 2- (j +2), …, the 2j th mapper 2-2 j.

The lower port of an EDFA (erbium doped fiber amplifier) 12 is connected with the right port of a photoelectric detector 13, the left port of the photoelectric detector 13 is connected with the right port of a 2 nd direct current biaser 10-2, the left port of the 2 nd direct current biaser 10-2 is connected with the right port of a pilot-removed cyclic prefix importer 14, the left port of the pilot-removed cyclic prefix importer 14 is connected with the right port of a 2 nd filter 8-2, the left port of the 2 nd filter 8-2 is connected with the right port of a j +1 th serial-parallel converter 5- (j +1), the j +1 th serial-parallel converter 5- (j +1) converts serial signals into parallel signals, and the left jxn port of the j +1 th serial-parallel converter is connected with the right j xn port of an FFT converter 15.

Left side 1 of FFT converter 15: the N port is connected with the right N port of the 2 nd parallel-serial converter 7-2, the output signal of the left port of the 2 nd parallel-serial converter 7-2 is divided into two paths, and the two paths are respectively connected with the two ports on the right sides of the 2j +1 st multiplier 4- (2j +1) and the 2j +2 nd multiplier 4- (2j +2), the two ports on the left sides of the 2j +1 st multiplier 4- (2j +1) and the 2j +2 nd multiplier 4- (2j +2) are respectively connected with the two ports on the right sides of the 1 st integrator 16-1 and the 2 nd integrator 16-2, and the two ports on the left sides of the 1 st integrator 16-1 and the 2 nd integrator 16-2 are respectively connected with the two ports on the right sides of the 1 st subtractor 17-1 and the 2 nd subtractor 17-2. The 1 st subtracter 17-1 has its lower port connected to the upper port of the j +1 th random number generator 3- (j + 1). The 2 nd subtracter 17-2 has its upper port connected to the lower port of the j +1 th random number generator 3- (j + 1). The left two ports of the 1 st subtracter 17-1 and the 2 nd subtracter 17-2 are respectively connected to the right two ports of the j +1 th mapper 2- (j +1), and the mapper 2- (j +1) restores the first path information m 1.

…。

Left side (j-1) N of FFT converter 15: the jN port is connected with the right N port of the j +1 th parallel-serial converter 7- (j +1), the output signal of the left port of the j +1 th parallel-serial converter 7- (j +1) is divided into two paths, respectively connected to the two ports on the right side of the 4j-1 th multiplier 4- (4j-1) and the 4 j-4 j multiplier 4-4j, the 4j-1 multiplier 4- (4j-1) and the 4j multiplier 4-4j have two left ports respectively connected to the two right ports of the 2j-1 integrator 16- (2j-1) and the 2j integrator 16-2j, and the 2j-1 integrator 16- (2j-1) and the 2j integrator 16-2j have two left ports respectively connected to the two right ports of the 2j-1 subtractor 17- (2j-1) and the 2j subtractor 17-2 j. The lower port of the 2j-1 subtracter 17- (2j-1) is connected with the upper port of the 2j random number generator 3-2 j. The 2j subtractor 17-2j has an upper port connected to a lower port of the 2j random number generator 3-2 j. The left two ports of the 2j-1 subtracter 17- (2j-1) and the 2j subtracter 17-2j are respectively connected to the right two ports of the 2j mapper 2-2j, and the mapper 2-2j restores the first path of information mj.

The principle of the secure communication system of the present embodiment will be described below in conjunction with the above-described system configuration.

In the invention, the random number generator is generated by the corresponding chaos sequence generated by the chaos generator through quantification, and the decoding requires that the chaos generator in the 1 st random number generator is synchronous with the chaos generator of the j +1 th random number generator, and …, the chaos generator of the j th random number generator is synchronous with the chaos generator of the 2j th random number generator. At the transmitting end, the 1 st signal generator generates an information sequence m1 to be transmitted to the 1 st mapper, and various bit combinations are mapped into x according to the mapping rule of the Gray code₁,y₁Two symbol data …, the j information generator generates information sequence mj to be transmitted to the j mapper, and various bit combinations are mapped into x according to the mapping rule of Gray code_j,y_jTwo symbol data. The 1 st random number generator generates random numbers which are respectively added with the symbol x by the 1 st adder and the 2 nd adder₁,y₁Adding to obtain encrypted new symbol x'₁,y′₁…, the random number generated by the jth random number generator is added to the symbol x by the 2j-1 and 2j adders, respectively_j,y_jAdding to obtain encryptedNovel symbol x'_j,y′_j. Thus, the encryption of the information is realized. Then the 1 st and 2 nd adders output symbols x'₁,y′₁The divided sides are multiplied by cos ω t and sin ω t and then added by a 2j +1 adder to generate a complex symbol x'₁+iy′₁Adding pilot training symbol, …, 2j-1, 2j adder output symbol x'_j,y′_jThe divided sides are multiplied by cos ω t and sin ω t and added by a 3j adder to generate a complex symbol x'_j+iy′_jAnd pilot training symbols are added, so that encrypted quadrature amplitude modulation (M-QAM) and pilot introduction are completed, and a transmitting end converts a transmitted digital signal into mapping of subcarrier amplitude.

Meanwhile, the complex symbol sequence formed by the 2j +1 st adder is converted into a parallel symbol stream by the 1 st serial-parallel converter. The 2j +2 th adder converts the serial symbol sequence into a parallel symbol stream … through a 2 nd serial-to-parallel converter, and the 3j adder converts the serial symbol sequence into a parallel symbol stream through a j th serial-to-parallel converter. And performing inverse fast Fourier transform by using an IFFT transformer to transform the spectrum expression of the data to a time domain. Every N serial-to-parallel converted symbols are modulated by a different subcarrier. The time domain symbol output by the IFFT converter is converted into a serial signal through a1 st parallel-serial converter, a1 st filter and a cyclic prefix leading-in device are used for cutting off a negative power part by a1 st direct current biaser, and the serial signal is converted into an optical signal through an optoelectronic modulator and transmitted in an optical fiber.

After optical fiber transmission, loss is compensated by an EDFA at a receiving end, information is amplified, an optical signal is converted into an electric signal by using a photoelectric detector, a negative power part is restored by using a 2 nd direct current biaser, filtering is carried out by using a 2 nd filter through a circulating prefix removing device, and a serial symbol is converted into a parallel symbol by using a j +1 th serial-parallel converter. The frequency domain symbols output by the FFT transformer are converted into j paths of serial symbols (N symbols per path) by j parallel-to-serial converters. Each path of serial symbols is divided into two paths, multiplied by cos ω t and-sin ω t respectively, and utilized by corresponding integratorsThe integration is performed over one period. The first path is x'₁,y′₁Subtracting the pilot frequency; …, respectively; line j gives x'_j,y′_jThe pilot is subtracted. First road symbol x'₁,y′₁Subtracting the random number generated by the j +1 th random number generator by a1 st subtracter to obtain x₁,y₁…, jth symbol x'_j,y′_jSubtracting the random number generated by the 2j random number generator by a j-th subtracter to obtain x_j,y_j. The first path passes x through the j +1 th mapper₁,y₁Original information m1, … is restored, the jth path x is mapped by a 2j mapper_j,y_jThe corresponding original information mj is restored.

Encryption is achieved by perturbing the symbol sequence generated by QAM with a random number. Both the transceiver ends must decrypt with the same random number.

The process of implementing communication is briefly summarized as follows:

1. the random numbers are synchronously generated at the transmitting end and the receiving end through chaos.

2. The information is QAM modulated.

3. The symbols generated by QAM modulation are encrypted with a random number.

4. Adding pilot training symbol, using IFFT to make Fourier transform, then making parallel-serial transform, adding prefix.

5. And adding the direct current bias to cut off the part with the negative amplitude.

6. The electrical signal is converted to an optical signal using an electro-optical modulator.

7. The receiving end converts the optical signal into an electrical signal using a detector.

8. After the serial-parallel transformation, the FFT is used for Fourier transformation.

9. The FFT data is decrypted using the random number.

10. And QAM demodulation is carried out to obtain a transmission signal.

While the preferred embodiments and principles of this invention have been described in detail, it will be apparent to those skilled in the art that variations may be made in the embodiments based on the teachings of the invention and such variations are considered to be within the scope of the invention.