阅读说明：本技术 异构光波束可见光通信物理层安全图样综合系统及方法 (Heterogeneous light beam visible light communication physical layer safety pattern comprehensive system and method ) 是由 丁举鹏 易芝玲 赵楷 张琳琳 王丽丽 于 2021-06-29 设计创作，主要内容包括：本发明涉及一种可见光通信技术领域,是一种异构光波束可见光通信物理层安全图样综合系统及方法,包括可见光接收装置和光源阵列；光源阵列包括多个可见光发射装置,可见光发射装置发射携带调制数据流的非朗伯异构光波束,其中调制数据流中包括保密信息；可见光接收装置,接收调制数据流的非朗伯异构光波束,获得对应的数据流。本发明根据异构光波束能为可见光通信物理层安全图样综合技术提供全新的空间自由度的特点,借助全新的空间自由度,减少甚至消除传统可见光通信物理层安全图样综合技术对巨大接入点几何站址资源的高度依赖性；并将多种迥异异构非朗伯光源波束的固态商用光源引入到同一光源阵列,使得高度兼容现有天花板发射器几何配置。(The invention relates to the technical field of visible light communication, in particular to a heterogeneous light beam visible light communication physical layer safety pattern comprehensive system and a method, which comprises a visible light receiving device and a light source array; the light source array comprises a plurality of visible light emitting devices, and the visible light emitting devices emit non-Lambertian heterogeneous light beams carrying modulated data streams, wherein the modulated data streams comprise secret information; the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulated data streams and obtains corresponding data streams. According to the characteristic that heterogeneous light beams can provide brand new spatial freedom for the visible light communication physical layer safety pattern comprehensive technology, the high dependence of the traditional visible light communication physical layer safety pattern comprehensive technology on huge access point geometric station resources is reduced or even eliminated by means of the brand new spatial freedom; and introducing solid state commercial light sources of a variety of disparate non-lambertian light source beams to the same light source array, making high compatibility with existing ceiling emitter geometries.)

1. A heterogeneous light beam visible light communication physical layer safety pattern comprehensive system is characterized by comprising a visible light receiving device and a light source array;

the light source array comprises a plurality of visible light emitting devices, and the visible light emitting devices emit non-Lambertian heterogeneous light beams carrying modulated data streams, wherein the modulated data streams comprise secret information;

the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulated data streams and obtains corresponding data streams.

2. The heterogeneous optical beam visible light communication physical layer security pattern synthesis system according to claim 1, wherein the visible light emitting device comprises a precoder, a first adjusting unit, a direct current biaser, a second adjusting unit, a predistorter, and a light source;

the precoder encodes a data stream, wherein the data stream comprises secret information;

the first adjusting unit modulates the coded data stream through the beam scaling vector to obtain a modulation data stream vector;

a DC bias device for generating a DC bias current;

the second regulating unit is used for superposing the modulation data stream vector on the direct current bias current to obtain an electric signal loaded with the modulation data stream;

a predistorter for compensating the electrical signal loaded with the modulated data stream;

a light source that emits a non-lambertian heterogeneous beam of light that carries a modulated data stream.

3. The system according to claim 2, wherein the first adjusting unit comprises a parameter setting module and a multiplication processing module;

the parameter setting module generates and outputs a beam scaling vector;

and the multiplication processing module multiplies the coded data stream by the beam scaling vector to obtain a modulation data stream vector.

4. The heterogeneous light beam visible light communication physical layer security pattern synthesis system according to claim 1, 2 or 3, wherein the visible light receiving means comprises a light beam receiving unit, an amplifying unit and a decoder;

the optical beam receiving unit is used for receiving the non-Lambert heterogeneous optical beam carrying the modulation data stream and converting the non-Lambert heterogeneous optical beam into an electric signal carrying the modulation data stream;

an amplifying unit for amplifying the electrical signal carrying the modulated data stream;

and the decoder is used for acquiring the modulated data stream, decoding and outputting a corresponding data stream.

5. A method for synthesizing a security pattern of a heterogeneous light beam visible light communication physical layer is characterized by comprising the following steps:

each visible light emitting device emits a non-Lambertian heterogeneous light beam carrying a modulation data stream;

the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulation data stream, and obtains a corresponding data stream after conversion, amplification and decoding.

6. The method of claim 5, wherein the visible light emitting device emits a non-Lambertian heterogeneous light beam carrying a modulated data stream, comprising:

encoding a data stream through a precoder, wherein the data stream comprises secret information;

generating and outputting a beam scaling vector through a parameter setting module, and multiplying the coded data stream by the beam scaling vector through a multiplication processing module to obtain a modulation data stream vector;

the direct current biaser generates direct current bias current, and the second adjusting unit superposes the modulation data stream vector on the direct current bias current to obtain an electric signal loaded with the modulation data stream;

after the electrical signal loaded with the modulation data stream is compensated by the predistorter, the light source emits a non-lambertian heterogeneous light beam carrying the modulation data stream.

7. The method as claimed in claim 5 or 6, wherein the visible light receiving device receives non-lambertian heterogeneous light beam of the modulated data stream, and converts, amplifies and decodes the non-lambertian heterogeneous light beam to obtain a corresponding data stream, and the method comprises:

the optical beam receiving unit receives a non-Lambert heterogeneous optical beam carrying modulation data stream and converts the non-Lambert heterogeneous optical beam carrying the modulation data stream into an electric signal carrying the modulation data stream;

amplifying the electrical signal carrying the modulated data stream by an amplifying unit;

the decoder obtains the modulated data stream, decodes the modulated data stream and outputs a corresponding data stream.

8. The method according to claim 7, wherein the amplified electrical signal carrying modulated data stream is as follows:

y(t)＝(w₁h₁ ^T+w₂h₂ ^T+…w_jh_j ^T…+w_Jh_J ^T)s(t)+n(t)

wherein h is_j ^TIs h_JTranspose of h_jIs a line-of-sight channel gain vector; w is a_jScaling a vector for the beam; s (t) is the secret information emitted by the visible light emitting device; n (t) is the signal noise captured by the visible light receiving device.

9. The method of claim 8, wherein the line-of-sight channel gain vector is as follows:

wherein J is the number of visible light emitting devices; n is a radical of_BThe number of non-Lambertian heterogeneous light beams in the same visible light emitting device;

wherein the content of the first and second substances,the line-of-sight channel gain of the ith type light beam of the jth visible light emitting device to any receiving position on the receiving plane is as follows:

wherein the content of the first and second substances,the sum total emission power of the ith type of light beam of the jth visible light emitting device; a. the_RIs a target userThe detection area of the optical beam receiving unit of (a);the LOS distance between the ith type optical beam of the jth visible light emitting device and the optical beam receiving unit of the target user; theta is an emergent pitch angle of the light beam relative to the normal direction of the current visible light emitting device; phi is the emergent azimuth angle of the light beam relative to the normal direction of the current visible light emitting device;is the radiation intensity of the ith type beam in the current jth visible light emitting device in the (theta, phi) spatial direction; gamma is the angle of incidence of the optical beam on the optical beam receiving unit of the target user; gamma ray_FOVA field angle of the optical beam receiving unit being a target user; r is the photo-responsivity of the optical beam receiving unit of the target user.

Technical Field

The invention relates to the technical field of visible light communication, in particular to a heterogeneous light beam visible light communication physical layer safety pattern comprehensive system and method.

Background

At present, the technical solution of physical layer security in visible light communication still pays high attention to the indoor scene where commercial solid-state light source arrays or spatially separated single light sources (i.e. visible light access points) are distributed. In such a scenario, each array of light sources or a spatially separated single light source acts as one visible light wireless access point. In design analysis of such scenes, the international published literature typically assumes that an array of light sources or spatially separated single light sources obey a lambertian spatial radiation model, satisfying omnidirectional symmetric radiation characteristics. Typically, 2015 researchers at the university of british columbia, canada, Ayman mosafa and Lutz Lampe, in published literature "Pattern Synthesis of Massive LED Arrays for Secure Visible Light Communication Links", propose that beam Pattern Synthesis will be achieved with large-scale LED Light source Arrays laid out on the ceiling.

The flexibility of this approach still comes with fundamental constraints. On the one hand, such solutions have to rely on distributed low-power LED light sources with a large number of isomorphic beams on the ceiling, in other words to provide the spatial freedom required for pattern synthesis with a huge number of light source sites; on the other hand, the scheme only supports a grid, particularly a dense grid-shaped light source arrangement paradigm, and does not relate to more flexible light source arrangement configuration such as honeycomb shape, random geometry shape and the like; furthermore, the approach described above is still limited to conventional lambertian, in particular low-power lambertian light sources, so that all light source beams belong to a homogenous light beam. Due to the isomorphism between the corresponding light beams, sufficient freedom of space design cannot be provided in the beam dimension, so the rigid requirement of the pattern synthesis technology on the freedom of space design must be met by means of a large amount of visible light communication site resources on the ceiling. Once the application scene does not have the sufficient available site resources (or the available site resources are severely limited), the corresponding spatial design freedom is necessarily greatly reduced, the existing secure visible light communication performance based on radiation pattern synthesis is necessarily greatly deteriorated, and the minimum attenuation level of the secure signals of all potential positions of the eavesdropping user is difficult to meet.

Disclosure of Invention

The invention provides a heterogeneous light beam visible light communication physical layer security pattern comprehensive system and method, overcomes the defects of the prior art, and can effectively solve the problems that the dependence degree of space design freedom and available site resources is high, and the space design freedom is easily reduced greatly when the available site resources are limited in a secret visible light communication scheme for radiation pattern synthesis based on an isomorphic Lambert light source.

One of the technical schemes of the invention is realized by the following measures: a heterogeneous light beam visible light communication physical layer safety pattern comprehensive system comprises a visible light receiving device and a light source array;

the light source array comprises a plurality of visible light emitting devices, and the visible light emitting devices emit non-Lambertian heterogeneous light beams carrying modulated data streams, wherein the modulated data streams comprise secret information;

the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulated data streams and obtains corresponding data streams.

The following is further optimization or/and improvement of the technical scheme of the invention:

the visible light emitting device comprises a precoder, a first adjusting unit, a direct current biaser, a second adjusting unit, a predistorter and a light source;

the precoder encodes a data stream, wherein the data stream comprises secret information;

the first adjusting unit modulates the coded data stream through the beam scaling vector to obtain a modulation data stream vector;

a DC bias device for generating a DC bias current;

the second regulating unit is used for superposing the modulation data stream vector on the direct current bias current to obtain an electric signal loaded with the modulation data stream;

a predistorter for compensating the electrical signal loaded with the modulated data stream;

a light source that emits a non-lambertian heterogeneous beam of light that carries a modulated data stream.

The first adjusting unit comprises a parameter setting module and a multiplication processing module;

the parameter setting module generates and outputs a beam scaling vector;

and the multiplication processing module multiplies the coded data stream by the beam scaling vector to obtain a modulation data stream vector.

The visible light receiving device comprises an optical beam receiving unit, an amplifying unit and a decoder;

the optical beam receiving unit is used for receiving the non-Lambert heterogeneous optical beam carrying the modulation data stream and converting the non-Lambert heterogeneous optical beam into an electric signal carrying the modulation data stream;

an amplifying unit for amplifying the electrical signal carrying the modulated data stream;

and the decoder is used for acquiring the modulated data stream, decoding and outputting a corresponding data stream.

The second technical scheme of the invention is realized by the following measures: a heterogeneous light beam visible light communication physical layer security pattern synthesis method comprises the following steps:

each visible light emitting device emits a non-Lambertian heterogeneous light beam carrying a modulation data stream;

the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulation data stream, and obtains a corresponding data stream after conversion, amplification and decoding.

The following is further optimization or/and improvement of the technical scheme of the invention:

the visible light emitting device emits a non-lambertian heterogeneous light beam carrying a modulated data stream, comprising:

encoding a data stream through a precoder, wherein the data stream comprises secret information;

generating and outputting a beam scaling vector through a parameter setting module, and multiplying the coded data stream by the beam scaling vector through a multiplication processing module to obtain a modulation data stream vector;

the direct current biaser generates direct current bias current, and the second adjusting unit superposes the modulation data stream vector on the direct current bias current to obtain an electric signal loaded with the modulation data stream;

after the electrical signal loaded with the modulation data stream is compensated by the predistorter, the light source emits a non-lambertian heterogeneous light beam carrying the modulation data stream.

The above-mentioned visible light receiving arrangement receives the non-lambertian heterogeneous light beam of the modulation data stream, obtains the corresponding data stream after converting, amplifying and decoding, including:

the optical beam receiving unit receives a non-Lambert heterogeneous optical beam carrying modulation data stream and converts the non-Lambert heterogeneous optical beam carrying the modulation data stream into an electric signal carrying the modulation data stream;

amplifying the electrical signal carrying the modulated data stream by an amplifying unit;

the decoder obtains the modulated data stream, decodes the modulated data stream and outputs a corresponding data stream.

The amplified electrical signal carrying the modulated data stream is as follows:

wherein the content of the first and second substances,is h_JTranspose of h_jIs a line-of-sight channel gain vector; w is a_jScaling a vector for the beam; s (t) is the secret information emitted by the visible light emitting device; n (t) is the signal noise captured by the visible light receiving device.

The line-of-sight channel gain vector is as follows:

wherein J is the number of visible light emitting devices; n is a radical of_BThe number of non-Lambertian heterogeneous light beams in the same visible light emitting device;

wherein the content of the first and second substances,the line-of-sight channel gain of the ith type light beam of the jth visible light emitting device to any receiving position on the receiving plane is as follows:

wherein the content of the first and second substances,the sum total emission power of the ith type of light beam of the jth visible light emitting device; a. the_RA detection area of the optical beam receiving unit for the target user;the LOS distance between the ith type optical beam of the jth visible light emitting device and the optical beam receiving unit of the target user; theta is an emergent pitch angle of the light beam relative to the normal direction of the current visible light emitting device; phi is the emergent azimuth angle of the light beam relative to the normal direction of the current visible light emitting device;is the radiation intensity of the ith type beam in the current jth visible light emitting device in the (theta, phi) spatial direction; gamma is the angle of incidence of the optical beam on the optical beam receiving unit of the target user; gamma ray_FOVA field angle of the optical beam receiving unit being a target user; r is the optical beam receiving sheet of the target userThe photoelectric responsivity of the cell.

The invention reduces or even eliminates the high dependence of the traditional visible light communication physical layer safety pattern comprehensive technology on huge access point geometric station site resources by means of brand new spatial freedom; therefore, the embodiment of the invention introduces various solid-state commercial light sources (such as LEDs and the like) with different heterogeneous non-Lambert light source beams into the same light source array, particularly the conformal light source array, so that the geometrical configuration of the existing ceiling emitter is highly compatible, the spatial geometrical position, the site density, the site distribution rule and other factors of the site of an access point (i.e. a visible light emitting device) are not required to be relied on according to the characteristic that the degree of freedom naturally comes from the difference of the space radiation characteristics among the beams, the comprehensive performance of the confidential visible light communication based on the radiation safety pattern is effectively ensured, and the minimum attenuation level of confidential signals of all potential positions of an eavesdropping user is met. Meanwhile, the embodiment of the invention can be compatible with grid access point configuration, can also be suitable for honeycomb and random geometric access point configuration, and has wide applicability and high configuration flexibility.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic configuration diagram of a grid-like arrangement of visible light emitting devices according to the present invention.

FIG. 3 is a schematic view of a honeycomb arrangement of visible light emitting devices according to the present invention.

FIG. 4 is a schematic diagram of a random geometric configuration of visible light emitting devices according to the present invention.

FIG. 5 is a schematic illustration of the method of example 3 of the present invention.

FIG. 6 is a schematic illustration of the method of example 4 of the present invention.

FIG. 7 is a schematic diagram of embodiments of examples 3 and 4 of the present invention.

FIG. 8 is a diagram illustrating a normalized pattern provided in a single target user scenario according to the present invention.

FIG. 9 is a diagram illustrating normalized patterns provided in a scenario with two target users according to the present invention.

Detailed Description

The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention.

The invention is further described with reference to the following examples and figures:

example 1: as shown in fig. 1, the embodiment discloses a heterogeneous light beam visible light communication physical layer security pattern integration system, which comprises a visible light receiving device and a light source array;

the light source array comprises a plurality of visible light emitting devices, and the visible light emitting devices emit non-Lambertian heterogeneous light beams carrying modulated data streams, wherein the modulated data streams comprise secret information;

the visible light receiving device receives the non-Lambertian heterogeneous light beams of the modulated data streams and obtains corresponding data streams.

The configuration of the plurality of visible light emitting devices in the light source array can be as shown in fig. 2, 3 and 4. The plurality of visible light emitting devices can be arranged in the same site to complete the intra-site isomerism, and can also be arranged among the sites to complete the inter-site isomerism.

The heterogeneous light beams can provide brand new and rich spatial freedom for the visible light communication physical layer safety pattern comprehensive technology due to the fact that the heterogeneous light beams have the characteristics of providing the brand new and rich spatial freedom for the same user position, and the brand new spatial freedom is used for reducing or even eliminating the high dependence of the traditional visible light communication physical layer safety pattern comprehensive technology on huge access point geometric site resources; therefore, the embodiment of the invention introduces various solid-state commercial light sources (such as LEDs and the like) with different heterogeneous non-Lambert light source beams into the same light source array, particularly the conformal light source array, so that the geometrical configuration of the existing ceiling emitter is highly compatible, the spatial geometrical position, the site density, the site distribution rule and other factors of the site of an access point (i.e. a visible light emitting device) are not required to be relied on according to the characteristic that the degree of freedom naturally comes from the difference of the space radiation characteristics among the beams, the comprehensive performance of the confidential visible light communication based on the radiation safety pattern is effectively ensured, and the minimum attenuation level of confidential signals of all potential positions of an eavesdropping user is met. Meanwhile, the embodiment of the invention can be compatible with grid access point configuration, can also be suitable for honeycomb and random geometric access point configuration, and has wide applicability and high configuration flexibility.

Example 2: as shown in fig. 1, the embodiment discloses a heterogeneous light beam visible light communication physical layer security pattern integration system, which comprises a visible light receiving device and a light source array arranged in a station site;

the light source array comprises a plurality of visible light emitting devices, and each visible light emitting device comprises a precoder, a first adjusting unit, a direct current biaser, a second adjusting unit, a predistorter and a light source;

the precoder encodes a data stream, wherein the data stream comprises secret information;

the first adjusting unit comprises a parameter setting module and a multiplication processing module; the parameter setting module generates and outputs a beam scaling vector; the multiplication processing module multiplies the coded data stream by the beam scaling vector to obtain a modulation data stream vector;

a DC bias device for generating a DC bias current;

the second regulating unit is used for superposing the modulation data stream vector on the direct current bias current to obtain an electric signal loaded with the modulation data stream; the second regulating unit can here be an adder;

a predistorter for compensating the electrical signal loaded with the modulated data stream;

the light source emits non-Lambert heterogeneous light beams carrying modulation data streams, and the light source can be a light source which can emit diverse heterogeneous light beams by additionally arranging secondary light distribution elements such as a reflecting cup, a free-form surface lens and the like on an original solid-state light source.

The visible light receiving device comprises an optical beam receiving unit, an amplifying unit and a decoder;

the optical beam receiving unit is used for receiving the non-Lambert heterogeneous optical beam carrying the modulation data stream and converting the non-Lambert heterogeneous optical beam into an electric signal carrying the modulation data stream; here, the optical beam receiving unit may be a photodiode;

an amplifying unit for amplifying the electrical signal carrying the modulated data stream;

the decoder is used for acquiring the modulated data stream, decoding and outputting a corresponding data stream; where the output data stream enters the target user.

Example 3: as shown in fig. 5, the embodiment discloses a heterogeneous light beam visible light communication physical layer security pattern synthesis method, which includes:

s101, each visible light emitting device emits a non-Lambertian heterogeneous light beam carrying modulation data stream;

and S102, the visible light receiving device receives the non-Lambert heterogeneous light beam of the modulation data stream, and the corresponding data stream is obtained after conversion, amplification and decoding.

Example 4: as shown in fig. 6, the present embodiment discloses a heterogeneous optical beam visible light communication physical layer security pattern synthesis method, including:

s201, encoding a data stream through a precoder, and outputting an encoded data stream S (t), wherein the data stream comprises secret information;

s202, generating and outputting a beam scaling vector w through a parameter setting module_jThen, the multiplication module combines the encoded data stream s (t) with the beam scaling vector w_jMultiplying to obtain a modulated data stream vector x (t);

where each visible light emitting device is provided with a beam scaling vector w_jThe beam scaling vector is specifically represented asWherein N is_BThe number of non-lambertian heterogeneous light beams in the same visible light emitting device,the scaling factor is integrated for the pattern associated with each light beam in a visible light emitting device. It should be noted that the embodiment of the present invention may provide the spatial freedom provided by the conventional I homogeneous lambertian light beam-based access points (i.e., visible light emitting devices), but the required site resource is only 1/N of the latter_B。

S203, the direct current biaser generates a direct current bias current I_DCThe second regulating unit superimposes the modulated data stream vector on the DC bias current I_DCObtaining an electrical signal loaded with a modulated data stream;

s204, after the electric signal loaded with the modulation data stream is compensated by the pre-compensator, the light source emits a non-Lambert heterogeneous light beam carrying the modulation data stream;

s205, the optical beam receiving unit receives the non-Lambert heterogeneous optical beam carrying the modulation data stream, and converts the non-Lambert heterogeneous optical beam carrying the modulation data stream into an electric signal carrying the modulation data stream;

s206, amplifying the electric signal carrying the modulation data stream through an amplifying unit, and outputting an electric signal y (t) carrying the modulation data stream;

wherein the content of the first and second substances,is h_JTranspose of h_jIs a line-of-sight channel gain vector; w is a_jScaling a vector for the beam; s (t) is secret information emitted by visible light emitting device, and satisfies | s (t) | ≦ I_DC(ii) a n (t) is signal noise captured by the visible light receiving device;

the signal-to-noise ratio of the superimposed noise security signal can be expressed as:

wherein, delta²Is the variance of the noise;

and a beam scaling vector w_jCorrespondingly, the line-of-sight channel gain vector associated with the jth visible light emitting device pattern synthesis scaling factor is:

wherein J is the number of visible light emitting devices; n is a radical of_BThe number of non-Lambertian heterogeneous light beams in the same visible light emitting device;synthesizing line-of-sight channel gains associated with scaling factors for respective patterns

Wherein the content of the first and second substances,the line-of-sight channel gain of the ith type light beam of the jth visible light emitting device to any receiving position on the receiving plane is as follows:

wherein the content of the first and second substances,the sum total emission power of the ith type of light beam of the jth visible light emitting device; a. the_RA detection area of the optical beam receiving unit for the target user;the LOS distance between the ith type optical beam of the jth visible light emitting device and the optical beam receiving unit of the target user is generally, the geometric dimension of the access point is much smaller than the distance from the access point to the receiving end, so that the distances from different optical beams in the same access point to the target user receiver are basically equal; theta is an emergent pitch angle of the light beam relative to the normal direction of the current visible light emitting device; phi is the emergent azimuth angle of the light beam relative to the normal direction of the current visible light emitting device;is the radiation intensity of the ith type light beam in the current jth visible light emitting device in the (theta, phi) space directionIf the space beam is a rotational symmetric beam, the radiation intensity is independent of the emitting azimuth angle phi, and the corresponding radiation intensity can be expressedGamma is the angle of incidence of the optical beam on the optical beam receiving unit of the target user; gamma ray_FOVA field angle of the optical beam receiving unit being a target user; r is the photoelectric responsivity of the optical beam receiving unit of the target user;

since the degree of difference of the gain vectors of the visible light channels is influenced by two factors: (1) the LED emission power difference between different types of light beams in the same visible light wireless access point; (2) and the radiation intensity difference of different light beams in the same visible light wireless access point to the same receiving position direction. The line-of-sight channel gain is determined through the above process.

S207, the decoder obtains the modulation data stream, decodes the modulation data stream and outputs a corresponding data stream.

In summary, the visible light signal received by the target user Bob can be expressed as:

y_Bob(t)＝(w₁ h_Bob,1 ^T+w₂ h_Bob,2 ^T+…w_j h_Bob,j ^T…+w_J h_Bob,J ^T)s(t)+n(t)

wherein h is_Bob,jIs the line of sight (LOS) channel gain vector for the jth access point to the target user Bob. A circular non-security area with a radius r is set around the target user Bob, that is, as long as the distance between the eavesdropper and Bob is greater than r, it is ensured that the security signal level captured by the eavesdropper is attenuated to a preset maximum threshold value, and specifically, the security setting relationship can be expressed as:

wherein (x)_B,y_B) For the position coordinates of the target user Bob, (x, y) for all potential eavesdroppers at a distance greater than r from the target user BobThe user accepts the location. By means of a linear programming tool, the condition of satisfying the constraint conditions and realizing the | w simultaneously can be searched₁h₁(x_B,y_B)^T+w₂h₂(x_B,y_B)^T+...w_jh_j(x_B,y_B)^T...+w_Jh_J(x_B,y_B)^TAnd l is the optimal weight vector w1 w2 … wJ corresponding to each access point required by the maximization of the value. The result of the normalized pattern of the present invention is shown in fig. 8 under the single target user Bob scenario.

When K target users exist in a visible light communication physical layer security pattern comprehensive scene of a heterogeneous light beam, a linear programming inequality needs to be listed for each target user respectively:

1 st target user:

the 2 nd target user:

…

the kth target user:

…

the Kth target user:

the linear programming tool can be used for searching and obtaining the condition meeting the constraint conditions and simultaneously realizing the following steps:

…

…

wherein the minimum value maximizes the required optimal weight vector w corresponding to each access point₁w₂…w_J. The results of the normalized patterns of the present invention are shown in fig. 9 in the context of two target users Bob.

The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect, and unnecessary technical features can be increased or decreased according to actual needs to meet the requirements of different situations.