阅读说明：本技术 一种基于空间位置点的安全通信系统 (Safety communication system based on spatial position point ) 是由 岳光荣 余代中 杨霖 曾鑫 于 2021-04-29 设计创作，主要内容包括：本发明公开了一种基于空间位置点的安全通信系统,属于通信技术领域。本发明所述系统包括发射端、接收端和训练协议；发射端包括发端时间计数模块、星座映射模块和发端相位旋转模块；接收端包括收端时间计数模块、接收端相位旋转模块和星座逆映射模块。本发明所述系统实现了距离域的安全性,只有在预期位置,接收机可以接收到正确的星座图,当接收机逐渐远离预期位置,接收信号被旋转、扭曲、缩小。预期位置的接收信号能量高于其他位置处的能量,并且预期位置处误差向量幅度值最小,保障了预期位置信号质量,在接收机偏离预期位置后能够有效的置乱并隐藏信号。本发明的收发端时间计数模块还能有效对抗系统时钟漂移对安全性能带来的负面影响。(The invention discloses a safe communication system based on spatial position points, and belongs to the technical field of communication. The system comprises a transmitting end, a receiving end and a training protocol; the transmitting end comprises a transmitting end time counting module, a constellation mapping module and a transmitting end phase rotation module; the receiving end comprises a receiving end time counting module, a receiving end phase rotation module and a constellation inverse mapping module. The system of the invention realizes the safety of the distance domain, the receiver can receive the correct constellation diagram only at the expected position, and when the receiver is gradually far away from the expected position, the received signal is rotated, twisted and reduced. The energy of the received signal at the expected position is higher than that at other positions, and the error vector amplitude value at the expected position is minimum, so that the signal quality at the expected position is guaranteed, and the signal can be effectively scrambled and hidden after the receiver deviates from the expected position. The time counting module of the transceiving end can also effectively resist the negative influence of the system clock drift on the safety performance.)

1. A safe communication system based on spatial position points is characterized by comprising a transmitting end, a receiving end and a training protocol; the transmitting end comprises a transmitting end time counting module, a constellation mapping module and a transmitting end phase rotation module; the receiving end comprises a receiving end time counting module, a receiving end phase rotation module and a constellation inverse mapping module;

when the transmitting terminal is powered on, the transmitting terminal time counting module executes the following steps:

s1.1: generating a periodic pulse having a period ofTI.e. the time interval between adjacent pulses isTA system clock period;

s1.2: starting upMThe forward counters start counting from 0,Mis a positive integer, usingIs shown asmThe current count value of each forward counter is less than or equal to 1m≤MWhen the next system clock rising edge comes, the firstmThe count value of each forward counter is updated as:

wherein the content of the first and second substances,tfor time, mod denotes fetchIn the rest part of the raw materials,Nis the maximum value of the forward counter;

s1.3: starting upMAn initial value of 0, usingIs shown asmThe current value of the register of each origin, when the next periodic pulse comesmThe value of each originating register is updated to:

when the receiving end is electrified, the receiving end time counting module executes the following steps:

s2.1: generating a periodic pulse having a period ofT；

S2.2: starting upMA counter for counting from 0Is shown asmThe current count value of the counter is inverted when the next rising edge of the system clock comesmThe count value of each counter is updated as:

s2.3: starting upMA receive register with an initial value of 0Is shown asmThe current value of the receive register, when the next periodic pulse arrives, the firstmThe value of each receive register is updated as:

after the transmitting end and the receiving end of the training protocol are powered on, the following steps are executed:

s3.1: generated at the transmitting endMRoad pilot signal；

S3.2: the originating phase rotation module generates a length ofNThe first lookup table is in the second lookup tableiThe value stored at an address is，，KIs a positive integer and is a non-zero integer,jis an imaginary unit;

s3.3: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

reading in a first lookup tableMA value stored at an address asMTraining phase rotation signal values for individual originating terminals；

S3.4: according toMTraining phase rotation signal value, pair for each originating terminalMThe pilot signal is phase-rotated to obtainMPilot signal after path rotation:

wherein the content of the first and second substances,is shown asmA pilot signal after the path rotation;

s3.5: will be provided withMAfter the path rotation, pilot signals are sequentially sent to a receiving end;

s3.6: the receiving end phase rotation module generates a length ofNWherein the second lookup table is in the first lookup tableiThe value stored at an address is；

S3.7: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMTraining phase rotation signal value by receiving end；

S3.8: to receiveMPerforming matched filtering and equalization operation on the pilot signals after the path rotation to obtainMWay receive pilot；

S3.9: according toMA receiving end trains phase rotation signal values, pairMThe pilot frequency is received and phase rotation is carried out to obtainMReceiving pilot frequency after path rotation:

s3.10: obtainingMReceiving pilot sum after path rotationMCross correlation function of the pilot signals:

wherein, the superscript indicates taking conjugation;

calculating a cross-correlation functionPhase ofTo findMPhase of output signal；

The transmitting end sends data to the receiving end, and the constellation mapping module executes the following steps when the sending bit stream arrives:

s4.1: according to predefinedLA constellation of order, mapping the transmitted bit stream to an inphase/quadrature signal s: (t) S, byt) For the original signal, generatingMA signal chipThe signal value of each signal chip is s: (t)/M；

S4.2: computingMSum of time-varying noise:

wherein the content of the first and second substances,is as followsmTime-varying noise;

s4.3: by usingMTime-varying noise pairMDisturbing each signal chip, wherein the specific disturbing mode is as follows:

wherein the content of the first and second substances,indicating after disturbancemA signal chip;

the originating phase rotation module is generated in the constellation mapping moduleMAfter each perturbed signal chip, performing the following steps:

s5.1: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

reading in a first lookup tableMA value stored at an address asMPhase rotation signal value of each transmitter；

S5.2: according toMIndividual originating phase rotation signal value, pairMPhase rotation is carried out on the disturbed signal chip to obtainMOne rotated transmitted signal chip:

wherein the content of the first and second substances,is shown asmTransmitting signal chips after rotation;

s5.3: will be provided withMTransmitting signal chips after rotation to a receiving end in sequence;

the receiving end phase rotation module sends the data after receiving the data from the transmitting endMAfter transmitting signal chips after rotating, executing the following steps:

s6.1: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMA receiving end phase rotation signal value；

S6.2: to receiveMCarrying out matched filtering and equalization operation on the rotated transmitting signal chips to obtainMA chip of received signal；

S6.3: according toMA receiving end phase rotation signal value, pairMPhase rotation is carried out on the received signal chips to obtainMRotated received signal chips:

wherein the content of the first and second substances,is shown asmReceiving signal chips after rotation;

the inverse mapping module is arranged inMAfter the rotated received signal chips arrive, the following steps are executed:

s7.1: phase of output signal generated according to training protocolψ ₁ ，ψ ₂ ，…，ψ _M Are respectively aligned withMThe rotated received signal chip is subjected to reverse phase rotation to obtainMOne compensated chip:

wherein the content of the first and second substances,is as followsmA compensated code chip;

s7.2: will be provided withMAdding the compensated chips to obtain a received signal：

S7.3: according toLStep constellation of received signalAnd carrying out inverse mapping to obtain a receiving bit stream.

2. The secure communication system based on spatial location points according to claim 1, wherein in S4.2, the time-varying noise generation method is: to 2MThe shift register with group length of 11 is given different initial values, shift operation is carried out when the rising edge of each system clock arrives, and the value of the last 5 bits of each group of shift registers is converted into decimal number to obtain 2MTime-varying random integerCalculating the firstmTime varying noise，Denotes No. 2m-1 time-varying random integer number,denotes No. 2m-1 time-varying random integer.

3. The secure communication system based on spatial location points of claim 1,T= 2250。

4. the secure communication system according to claim 1, wherein the system clock period is 1/(125 MHz).

5. The secure communication system based on spatial location points of claim 1,L= 4。

6. the secure communication system based on spatial location points of claim 1,M= 16。

7. the secure communication system based on spatial location points of claim 1,N= 512。

8. the secure communication system based on spatial location points of claim 1,K= 2。

Technical Field

The invention belongs to the technical field of communication, and particularly relates to a safe communication system based on spatial position points.

Background

In communication, a system is vulnerable to eavesdropping, counterfeiting, tampering, and the like. Existing security mechanisms are commonly used in current communication systems, but the security mechanisms face difficult key distribution, are not suitable for large-scale networks with limited resources, and are difficult to meet the security requirements of future communication. In order to solve the problems, physical layer security communication is proposed at home and abroad, a security gateway is moved forward, the dependence on a long key is eliminated by utilizing the randomness (interference, noise and the like) of the physical layer, the security technology of the spatial domain physical layer, such as spatial domain beam forming and direction modulation, which is widely researched at present can only solve the security problem of an angular domain, and the security of a distance domain is difficult to guarantee by the prior art. However, the security of the distance domain has an important significance in wired/wireless communication, and although some distance domain secure communication algorithms are proposed in the academic circles and the industrial circles at home and abroad, no prototype system has been provided to confirm the realizability of the algorithms so far. There is also no specific simple and easy implementation for distance domain secure communication, so there is still a huge gap between theory and implementation for distance domain secure communication.

Disclosure of Invention

The object of the present invention is to overcome the above mentioned drawbacks of the prior art and to provide a secure communication system based on spatial location points.

The technical problem proposed by the invention is solved as follows:

a safety communication system based on spatial position points comprises a transmitting end, a receiving end and a training protocol; the transmitting end comprises a transmitting end time counting module, a constellation mapping module and a transmitting end phase rotation module; the receiving end comprises a receiving end time counting module, a receiving end phase rotation module and a constellation inverse mapping module;

when the transmitting terminal is powered on, the transmitting terminal time counting module executes the following steps:

s1.1: generating a periodic pulse having a period ofTI.e. the time interval between adjacent pulses isTA system clock period;

s1.2: starting upMAn uprightThe counter is started to count from 0 and,Mis a positive integer, usingIs shown asmThe current count value of each forward counter is less than or equal to 1m≤MWhen the next system clock rising edge comes, the firstmThe count value of each forward counter is updated as:

wherein the content of the first and second substances,tmod represents the remainder for time, and,Nis the maximum value of the forward counter;

s1.3: starting upMAn initial value of 0, usingIs shown asmThe current value of the register of each origin, when the next periodic pulse comesmThe value of each originating register is updated to:

when the receiving end is electrified, the receiving end time counting module executes the following steps:

s2.1: generating a periodic pulse having a period ofT；

S2.2: starting upMA counter for counting from 0Is shown asmThe current count value of the counter is inverted when the next rising edge of the system clock comesmThe count value of each counter is updated as:

s2.3: starting upMA receive register with an initial value of 0Is shown asmThe current value of the receive register, when the next periodic pulse arrives, the firstmThe value of each receive register is updated as:

after the transmitting end and the receiving end of the training protocol are powered on, the following steps are executed:

s3.1: generated at the transmitting endMRoad pilot signal；

S3.2: the originating phase rotation module generates a length ofNThe first lookup table is in the second lookup tableiThe value stored at an address is，，KIs a positive integer and is a non-zero integer,jis an imaginary unit;

s3.3: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

reading in a first lookup tableMA value stored at an address asMTraining phase rotation signal values for individual originating terminals；

S3.4: according toMTraining phase rotation signal value, pair for each originating terminalMThe pilot signal is phase-rotated to obtainMPilot signal after path rotation:

wherein the content of the first and second substances,is shown asmA pilot signal after the path rotation;

s3.5: will be provided withMAfter the path rotation, pilot signals are sequentially sent to a receiving end;

s3.6: the receiving end phase rotation module generates a length ofNWherein the second lookup table is in the first lookup tableiThe value stored at an address is；

S3.7: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMTraining phase rotation signal value by receiving end；

S3.8: to receiveMPerforming matched filtering and equalization operation on the pilot signals after the path rotation to obtainMWay receive pilot；

S3.9: according toMA receiving end trains phase rotation signal values, pairMThe pilot frequency is received and phase rotation is carried out to obtainMReceiving pilot frequency after path rotation:

s3.10: obtainingMReceiving pilot sum after path rotationMCross correlation function of the pilot signals:

wherein, the superscript indicates taking conjugation;

calculating a cross-correlation functionPhase ofTo findMPhase of output signal；

The transmitting end sends data to the receiving end, and the constellation mapping module executes the following steps when the sending bit stream arrives:

s4.1: according to predefinedLA constellation of order, mapping the transmitted bit stream to an inphase/quadrature signal s: (t) S, byt) For the original signal, generatingMA signal chipThe signal value of each signal chip is s: (t)/M；

S4.2: computingMSum of time-varying noise:

wherein the content of the first and second substances,is as followsmTime-varying noise;

s4.3: by usingMTime-varying noise pairMDisturbing each signal chip, wherein the specific disturbing mode is as follows:

wherein the content of the first and second substances,indicating after disturbancemA signal chip;

the originating phase rotation module is generated in the constellation mapping moduleMAfter each perturbed signal chip, performing the following steps:

s5.1: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

reading in a first lookup tableMA value stored at an address asMPhase rotation signal value of each transmitter；

S5.2: according toMIndividual originating phase rotation signal value, pairMPhase rotation is carried out on the disturbed signal chip to obtainMOne rotated transmitted signal chip:

wherein the content of the first and second substances,is shown asmTransmitting signal chips after rotation;

s5.3: will be provided withMTransmitting signal chips after rotation to a receiving end in sequence;

the receiving end phase rotation module sends the data after receiving the data from the transmitting endMAfter transmitting signal chips after rotating, executing the following steps:

s6.1: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMA receiving end phase rotation signal value；

S6.2: to receiveMCarrying out matched filtering and equalization operation on the rotated transmitting signal chips to obtainMA chip of received signal；

S6.3: according toMA receiving end phase rotation signal value, pairMPhase rotation is carried out on the received signal chips to obtainMRotated received signal chips:

wherein the content of the first and second substances,is shown asmReceiving signal chips after rotation;

the inverse mapping module is arranged inMAfter the rotated received signal chips arrive, the following steps are executed:

s7.1: phase of output signal generated according to training protocolψ ₁ ，ψ ₂ ，…，ψ _M Are respectively aligned withMThe rotated received signal chip is subjected to reverse phase rotation to obtainMOne compensated chip:

wherein the content of the first and second substances,is as followsmA compensated code chip;

s7.2: will be provided withMAdding the compensated chips to obtain a received signal：

S7.3: according toLStep constellation of received signalAnd carrying out inverse mapping to obtain a receiving bit stream.

Further, in S4.2, the time-varying noise generation method includes: to 2MThe shift register with group length of 11 is given different initial values, shift operation is carried out when the rising edge of each system clock arrives, and the value of the last 5 bits of each group of shift registers is converted into decimal number to obtain 2MTime-varying random integerCalculating the firstmTime varying noise，Denotes No. 2m-1 time-varying random integer number,denotes No. 2m-1 time-varying random integer.

Further, in the above-mentioned case,T= 2250。

further, the system clock period is 1/(125 MHz).

Further, in the above-mentioned case,L= 4。

further, in the above-mentioned case,M= 16。

further, in the above-mentioned case,N= 512。

further, in the above-mentioned case,K= 2。

the invention has the beneficial effects that:

the system of the invention can generate the distance dependency of the received signal, thereby realizing the safety of the distance domain, the receiver can receive the correct constellation diagram only at the expected position, namely the receiver position when the pilot frequency is sent by the training protocol, and when the receiver is gradually far away from the expected position, the received signal is rotated, twisted and reduced. Near the expected location, the received signal energy at the expected location is higher than at other locations, and the Error Vector Magnitude (EVM) value at the expected location is minimal, effectively scrambling and concealing the signal after the receiver has deviated from the expected location while preserving the signal quality at the expected location. In addition, the time counting module of the transceiving end can also effectively resist the negative influence of the system clock drift on the safety performance.

Drawings

Fig. 1 is a schematic structural composition diagram of a secure communication system based on spatial location points according to the present invention;

FIG. 2 is a diagram illustrating the test results of the constellation of the received signal at the expected location in the system according to one embodiment;

FIG. 3 is a graph of a test result of a constellation of signals received by the system according to one embodiment at a distance of 8 meters from an expected location;

FIG. 4 is a graph of a test result of a constellation of signals received by the system according to an embodiment at a distance of 20 meters from an expected location;

FIG. 5 is a graph of the test results of a constellation of signals received by the system according to one embodiment at a distance of 32 meters from the expected location;

fig. 6 is a graph of test results of received signal energy and EVM at different locations of the system according to an embodiment.

Detailed Description

The invention is further described below with reference to the figures and examples.

The embodiment provides a secure communication system based on a spatial location point, and a schematic structural composition diagram of the system is shown in fig. 1, and the system comprises a transmitting end, a receiving end and a training protocol; the transmitting end comprises a transmitting end time counting module, a constellation mapping module and a transmitting end phase rotation module; the receiving end comprises a receiving end time counting module, a receiving end phase rotation module and a constellation inverse mapping module;

when the transmitting terminal is powered on, the transmitting terminal time counting module executes the following steps:

s1.1: generating periodic pulses of a periodIs composed ofT= 2250 that the time interval between adjacent pulses isT= 2250 system clock cycles, wherein the system clock cycles are 1/(125 MHz);

s1.2: starting upM= The 16 forward counters start counting from 0,Mis a positive integer, usingIs shown asmThe current count value of each forward counter is less than or equal to 1m≤MWhen the next system clock rising edge comes, the firstmThe count value of each forward counter is updated as:

wherein the content of the first and second substances,tmod represents the remainder for time, and,N= 512 is a preset maximum value of the forward counter;

s1.3: starting upMAn initial value of 0, usingIs shown asmThe current value of the register of each origin, when the next periodic pulse comesmThe value of each originating register is updated to:

at the rest of the time, the time of day,Mthe value of each originating register remains unchanged;

when the receiving end is electrified, the receiving end time counting module executes the following steps:

s2.1: generating a periodic pulse having a period ofT；

S2.2: starting upMA counter for counting from 0Is shown asmThe current count value of the counter is inverted when the next rising edge of the system clock comesmThe count value of each counter is updated as:

s2.3: starting upMA receive register with an initial value of 0Is shown asmThe current value of the receive register, when the next periodic pulse arrives, the firstmThe value of each receive register is updated as:

at the rest of the time, the time of day,Mthe value of each receiving end register is kept unchanged;

after the transmitting end and the receiving end of the training protocol are powered on, the following steps are executed:

s3.1: generated at the transmitting endMRoad pilot signalWhereinMThe pilot signals of the paths are Gray sequences with the length of 64;

s3.2: the originating phase rotation module generates a length ofNThe first lookup table is in the second lookup tableiThe value stored at an address is，，K= 2 is a positive integer which is preset in advance,jis an imaginary unit;

s3.3: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

reading in a first lookup tableMA value stored at an address asMTraining phase rotation signal values for individual originating terminals；

S3.4: according toMTraining phase rotation signal value, pair for each originating terminalMThe pilot signal is phase-rotated to obtainMPilot signal after path rotation:

wherein the content of the first and second substances,is shown asmA pilot signal after the path rotation;

s3.5: will be provided withMAfter the path rotation, pilot signals are sequentially sent to a receiving end;

s3.6: the receiving end phase rotation module generates a length ofNWherein the second lookup table is in the first lookup tableiThe value stored at an address is；

S3.7: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMTraining phase rotation signal value by receiving end；

S3.8: to receiveMPerforming matched filtering and equalization operation on the pilot signals after the path rotation to obtainMWay receive pilot；

S3.9: according toMTraining of receiving endPhase rotation signal value, pairMThe pilot frequency is received and phase rotation is carried out to obtainMReceiving pilot frequency after path rotation:

s3.10: obtainingMReceiving pilot sum after path rotationMCross correlation function of the pilot signals:

wherein, the superscript indicates taking conjugation;

calculating a cross-correlation functionPhase ofTo findMPhase of output signal；

The transmitting end sends data to the receiving end, and the constellation mapping module executes the following steps when the sending bit stream arrives:

s4.1: according to predefinedL=4 constellation, mapping the transmit bit stream to an in-phase/quadrature (I/Q) signal s: (t) S, byt) For the original signal, generatingMA signal chipThe signal value of each signal chip is s: (t)/M；

S4.2: computingMSum of time-varying noise:

wherein the content of the first and second substances,is as followsmTime-varying noise;

in this embodiment, the time-varying noise generation method includes: to 2MThe shift register with group length of 11 is given different initial values, shift operation is carried out when the rising edge of each system clock arrives, and the value of the last 5 bits of each group of shift registers is converted into decimal number to obtain 2MTime-varying random integerCalculating the firstmTime varying noise，Denotes No. 2m-1 time-varying random integer number,denotes No. 2m-1 time-varying random integer.

S4.3: by usingMTime-varying noise pairMDisturbing each signal chip, wherein the specific disturbing mode is as follows:

wherein the content of the first and second substances,indicating after disturbancemA signal chip;

the originating phase rotation module is generated in the constellation mapping moduleMAfter each perturbed signal chip, performing the following steps:

s5.1: when the periodic pulse generated by the originating time counting module arrives, the method comprisesMThe current value of each originating register is an address; at other times, in order toMThe current count value of each forward counter is an address;

in the first placeReading from a lookup tableMA value stored at an address asMPhase rotation signal value of each transmitter；

S5.2: according toMIndividual originating phase rotation signal value, pairMPhase rotation is carried out on the disturbed signal chip to obtainMOne rotated transmitted signal chip:

wherein the content of the first and second substances,is shown asmTransmitting signal chips after rotation;

s5.3: will be provided withMTransmitting signal chips after rotation to a receiving end in sequence;

the receiving end phase rotation module sends the data after receiving the data from the transmitting endMAfter transmitting signal chips after rotating, executing the following steps:

s6.1: when the periodic pulse generated by the receiving end time counting module arrives, the receiving end time counting module is used for counting the time of the periodic pulseMThe current value of each receiving end register is an address; at other times, in order toMThe current count value of each counter is an address;

reading in the second lookup tableMA value stored at an address asMA receiving end phase rotation signal value；

S6.2: to receiveMCarrying out matched filtering and equalization operation on the rotated transmitting signal chips to obtainMA chip of received signal；

S6.3: according toMA receiving end phase rotation signal value, pairMPhase rotation is carried out on the received signal chips to obtainMAfter rotatingReception of signal chips:

wherein the content of the first and second substances,is shown asmReceiving signal chips after rotation;

the inverse mapping module is arranged inMAfter the rotated received signal chips arrive, the following steps are executed:

s7.1: phase of output signal generated according to training protocolψ ₁ ，ψ ₂ ，…，ψ _M Are respectively aligned withMThe rotated received signal chip is subjected to reverse phase rotation to obtainMOne compensated chip:

wherein the content of the first and second substances,is as followsmA compensated code chip;

s7.2: will be provided withMAdding the compensated chips to obtain a received signal：

S7.3: according to predefinedLStep constellation of received signalAnd carrying out inverse mapping to obtain a receiving bit stream.

With this embodiment, the distance dependency of the received signal can be generated to realize the safety of the distance domain, the test result graphs of the received signal constellation diagram at different positions are shown in fig. 2-5, only at the expected position, i.e. the position of the receiver in the training mode, the receiver can receive the correct QPSK constellation diagram, and when the receiver is gradually far away from the expected position, the received signal is rotated and distorted until the received signal is completely submerged in the noise. Fig. 6 shows a test result graph of received signal energy and EVM at different positions, and near an expected position, the signal energy at the expected position is higher than the energy at other positions, and an Error Vector Magnitude (EVM) value at the expected position is minimum, which indicates that the invention can guarantee the signal quality at the expected position, and can effectively scramble and hide signals after a receiver deviates from the expected position, thereby achieving the purpose of secure communication.