WO2023040228A1 - 一种可见光定位辅助的多用户光通信系统及方法 - Google Patents

一种可见光定位辅助的多用户光通信系统及方法 Download PDF

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WO2023040228A1
WO2023040228A1 PCT/CN2022/082159 CN2022082159W WO2023040228A1 WO 2023040228 A1 WO2023040228 A1 WO 2023040228A1 CN 2022082159 W CN2022082159 W CN 2022082159W WO 2023040228 A1 WO2023040228 A1 WO 2023040228A1
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visible light
user
optical communication
automatic tracking
communication device
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PCT/CN2022/082159
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English (en)
French (fr)
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李正鹏
罗倩倩
李智
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湖北文理学院
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/16—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using electromagnetic waves other than radio waves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the invention belongs to the technical field of visible light communication, and in particular relates to a visible light positioning-assisted multi-user optical communication system and method.
  • Visible Light Communication is considered by the industry to be a wireless personal area network (Wireless Personal Area Network, WPAN) communication due to its advantages such as no spectrum authorization, high security and confidentiality, 400-800THz ultra-wide spectrum and no electromagnetic radiation.
  • WPAN Wireless Personal Area Network
  • VLC's transmitting devices mainly use light emitting diodes (Light Emitted Diode, LED), laser diodes (Laser Diode, LD) and the newly developed super radiant diodes (SLD), and receiving devices usually use photodiodes (PIN), avalanche diodes ( APD) and image sensors, etc.
  • LED adopts spontaneous emission mode, the emitted light is incoherent light, the spectrum is wide, the emission direction is omnidirectional emission, and the total output power can be high.
  • the optical power density is low.
  • LD adopts the amplified stimulated radiation mode, and the light emitted is coherent light with narrow spectrum, strong directivity of emission direction, high output power and high optical power density.
  • the main structure of the VLC system verified by experiments is still point-to-point communication. If LEDs are used, it is necessary to install a condenser lens at the front of the LED to form a parallel beam, and at the same time install a convex lens at the receiving end to make the light converge.
  • PD Photo Detector
  • this point-to-point VLC system is applied in an actual WPAN scenario, it will face some bottleneck problems.
  • a micro base station will serve multiple users at the same time. Therefore, it is required to realize a point-to-surface or even point-to-three-dimensional omnidirectional radiation communication just like WiFi.
  • the VLC micro base station uses LEDs, Although point-to-face coverage can also be achieved, the low radiated power density of LEDs results in weak signals received by PDs and a low signal-to-noise ratio, which affects communication quality.
  • the Chinese patent with publication number CN113162688A discloses a visible light two-way communication and positioning system, including a first communication node and a second communication node, and the first communication node includes a positioning light source, a first communication light source, and a PIN/APD detector module And the first driving device assembly that drives the first communication light source and the PIN/APD detector module to rotate;
  • the second communication node includes a composite receiver, a second communication light source and a second drive device that drives the second communication light source to rotate;
  • the composite receiver The receiver is used to receive signals from the positioning light source and the first communication light source, and the composite receiver includes a plurality of detectors; the PIN/APD detector module is used to receive signals from the second communication light source.
  • the system can realize the simultaneous uploading and downloading of data by two communication nodes in the visible light band, and can realize the positioning and tracking function, so that even if the two communication nodes move relative to each other, they can maintain the first communication light source and composite receiver and
  • the alignment of the second communication light source and the PIN/APD detector module ensures communication quality.
  • This patent can locate and track the location information of nodes in real time, realize real-time alignment of two communication nodes, and ensure the reliability and stability of visible light communication.
  • the purpose of the present invention is to provide a visible light positioning-assisted multi-user optical communication system and method for the point-to-point communication link connection problem between VLC micro base stations and multiple users at random positions in the prior art. Multiple users provide broadband transmission services with little mutual interference and good application value.
  • a multi-user optical communication system assisted by visible light positioning including a VLC micro base station and a user receiver;
  • the VLC micro base station includes a mounting plate, a visible light locator is provided in the middle of the bottom surface of the mounting plate, and the bottom surface of the mounting plate surrounds
  • the visible light locator is equipped with several automatic tracking light communication devices;
  • the visible light locator is connected with multiple automatic tracking light communication devices through a serial bus, so as to realize the two-way communication between the master and slave devices, wherein the visible light locator is the main device, and the automatic The tracking optical communication device is a slave device;
  • the visible light locator cyclically broadcasts the VLC micro base station ID and the current working status data of the automatic tracking optical communication device to the coverage area;
  • the user receiver sends its own 3D position coordinates and user information to the visible light locator Identity identification:
  • the visible light locator specifies the nearest and idle automatic tracking optical communication device to establish a communication link with the user receiver according to the user's 3D position coordinates and
  • the visible light positioner includes a mount, a heat sink, and a positive N prism, N ⁇ 3, and N ⁇ Z + ;
  • the positive N prism is mounted on the mount through a heat sink, and the mount is mounted on The middle part of the bottom surface of the mounting plate;
  • a control module, an LED drive modulation module and an infrared receiving module are arranged in the mounting seat, and the LED driving modulation module and the infrared receiving module are respectively connected with the control module;
  • a first infrared receiving tube, the first infrared receiving tube is connected with the infrared receiving module;
  • the N+1 faces of the positive N prism are provided with circuit substrates, and each of the circuit substrates is provided with a LED lights, the LED lights are connected to the LED drive modulation module through the circuit substrate;
  • the first infrared receiving tube is used to receive the 3D position coordinate information sent by the user;
  • the LED drive modulation module is used to drive the LED lights in different orientations to emit different A frequency shift keying
  • the automatic tracking optical communication device includes a base on which a horizontal rotation servo mechanism, a pitch rotation servo mechanism and a beam projector are installed in sequence; a data processing unit, a drive unit and a communication unit are arranged in the base.
  • Signal processing unit, the drive unit and the communication signal processing unit are respectively connected with the data processing unit;
  • the communication signal processing unit has an Ethernet port and an optical fiber port;
  • the Ethernet port is connected to an indoor optical fiber cat, or an optical fiber
  • the port is connected to the indoor optical fiber;
  • the two network ports are connected to the public network or mobile communication network.
  • the output end of the beam projector is provided with a light emitting device and a second infrared receiving tube, and the light emitting device and the second infrared receiving tube are respectively connected to the data processing unit;
  • the light emitting device is used for downlink broadband data
  • the transmission of the second infrared receiving tube is used for the reception of uplink broadband data;
  • the drive unit is used to drive the horizontal rotation servo mechanism and the pitch rotation servo mechanism to adjust the horizontal direction and pitch angle of the beam projector;
  • the data processing The unit is used to process the data sent by the visible light locator and generate target tracking signals to the drive unit.
  • the user receiver includes a signal processing module, a photodiode connected to the signal processing module, an infrared emission tube and a distance measuring probe; Optical signal; the infrared emitting tube is used to send infrared signals to the visible light locator and automatic tracking optical communication device; the distance measuring probe is used to measure its own height data; the signal processing module is used to process and receive signals, and generate Modulated signal.
  • the present invention also proposes a multi-user optical communication method assisted by visible light positioning, which includes the following steps:
  • the visible light locator cyclically broadcasts the VLC micro base station ID and the current working status identification data of the automatic tracking optical communication device towards its coverage area;
  • the user receiver After receiving the VLC micro base station ID and the current working state identification data of the automatic tracking optical communication device, the user receiver selects an unoccupied frequency resource as the carrier according to the current working state identification data, and uploads the user's data to the visible light locator. 3D location coordinates and identification;
  • the automatic tracking optical communication device adjusts the horizontal direction and pitch angle of its beam projector according to the user's 3D position coordinates, aligns the beam projector with the user receiver, and sends a channel estimation signal to the user receiver;
  • the user receiver After receiving the channel estimation signal, the user receiver evaluates whether the channel meets the broadband communication requirement, and if so, starts broadband data transmission; if not, rechecks.
  • the visible light locator first obtains the 3D position coordinates of all idle automatic tracking optical communication devices, and then selects the automatic tracking optical communication device closest to the user's 3D position coordinates; after the communication link is established, it analyzes the Whether the communication link overlaps with other working communication links, and if so, select the adjacent automatic tracking optical communication device to re-establish the communication link with the user receiver until the re-established communication link overlaps with other working communication links Roads do not overlap.
  • the working communication link can be migrated to an idle automatic tracking optical communication device that does not cause overlapping of beams through analysis and scheduling, so as to allow Space communication links are given to new access users to ensure that the communication links do not overlap to the greatest extent.
  • the user receiver is equipped with an inertial sensor. If the user receiver shakes significantly and the shake value exceeds a set threshold, the user receiver will re-estimate its own 3D position coordinates and transfer the new 3D position coordinates to Upload the visible light locator, and the visible light locator transmits the new 3D position coordinates to the automatic tracking optical communication device, and the automatic tracking optical communication device corrects the horizontal direction and pitch angle of the beam projector in real time according to the new 3D position coordinates, so that the beam The projecting direction of the projector is always aimed at the user receiver.
  • the stereoscopic 3D unit normal vector of the i-th LED light is defined as:
  • the 3D coordinate vector of the PD (photodetector) on the receiver user equipment (User Equipment, UE) is defined as:
  • the unit normal vector of PD (photodetector) is defined as: n U
  • the 3D direction vector from the LED light position to the UE position is:
  • the radiation angle between the i-th LED relative to the UE is defined as ⁇ i , then:
  • the incident angle of UE relative to the i-th LED is defined as Then there are:
  • the light intensity of the light signal of the i-th LED wick reaching the UE through visible propagation can be expressed as:
  • ⁇ U is the response coefficient of PD
  • PL is the radiation light power of LED
  • n is the Lambertian radiation lobe modulus (representing the directionality of the light source)
  • m is the order of PD
  • AU is the receiving area of PD
  • F i is the indicator function, when the function is in takes the value 1 when , and takes the value 0 in other cases, where Indicates the field of view of the PD;
  • the present invention proposes a method for quickly estimating the 3D position coordinates of the user receiver, the steps are as follows:
  • the eigenvalues are sorted from small to large, and the eigenvector corresponding to the smallest eigenvalue is obtained.
  • This eigenvector is the optimal solution of the 3D normalized relative coordinates from the visible light locator to the UE, expressed as
  • the receiver uses the ranging probe and the inertial sensor to obtain the distance from the UE to the ceiling or the floor, and further obtains the vertical distance h D from the UE to the visible light locator;
  • the fourth step through the formula
  • the three-dimensional coordinates U of the UE are estimated, where [x L , y L , z L ] are the 3D coordinates of the visible light locator.
  • the beneficial effect of the present invention is: the present invention connects a visible light locator with multiple automatic tracking optical communication devices through a serial bus, and matches the most suitable automatic tracking for the user according to the actual 3D position coordinates of the user.
  • the optical communication device can effectively solve the bottleneck problem of poor communication quality and high bit error rate in point-to-plane or three-dimensional space of optical communication; (2) each automatic tracking optical communication device of the present invention and the user equipment still use The point-to-point communication greatly saves the power and energy consumption of the transmitting equipment; (3) the space beam isolation is adopted between each communication link of the present invention, the information transmission interference between different users is small, and the communication quality is further improved.
  • FIG. 1 is a schematic structural diagram of a multi-user optical communication system assisted by visible light positioning in an embodiment of the present invention.
  • Fig. 2 is an inverted front view of the visible light positioner in the embodiment of the present invention.
  • Fig. 3 is a side view of the visible light positioner in the embodiment of the present invention.
  • Fig. 4 is a schematic structural diagram of an automatic tracking optical communication device in an embodiment of the present invention.
  • Fig. 5 is a simplified plan view of the visible light positioner in the embodiment of the present invention.
  • FIG. 6 is a configuration diagram of an application scenario of an optical communication system in an embodiment of the present invention.
  • Fig. 7 is a schematic diagram of three-dimensional distribution of positioning error performance simulation in an embodiment of the present invention.
  • 100 mounting plate; 200, visible light locator; 201, mounting seat; 202, radiator; 203, quadrangular platform; 204, control module; 205, LED drive modulation module; 206, infrared receiving module; 207, 208, circuit substrate; 209, LED lamp; 300, automatic tracking optical communication device; 301, base; 302, horizontal rotation servo mechanism; 303, pitch rotation servo mechanism; 304, beam projector; 305, Data processing unit; 306, drive unit; 307, communication signal processing unit; 308, light emitting device; 309, second infrared receiving tube; 400, user receiver; 401, photodiode; 402, infrared emitting tube; 403, measuring from the probe; 500, the user terminal.
  • this embodiment provides a multi-user optical communication system assisted by visible light positioning, including a VLC micro base station and a user receiver 400;
  • the VLC micro base station includes a mounting board 100, and the bottom surface of the mounting board 100
  • a visible light locator 200 is provided in the middle, and eight automatic tracking light communication devices 300 are arranged at equal intervals around the visible light locator 200 on the bottom surface of the mounting plate 100;
  • the visible light locator 200 communicates with the eight automatic tracking light communication devices through a serial bus
  • the device 300 is connected to realize two-way communication between the master and slave devices, wherein the visible light locator 200 is the master device, and the automatic tracking optical communication device 300 is the slave device;
  • the visible light locator 200 cyclically broadcasts the VLC micro base station ID and automatic tracking to the coverage area
  • the user receiver 400 sends its own 3D position coordinates and user identification to the visible light locator 200;
  • the closest and idle automatic tracking optical communication device 300 establishes a
  • the visible light positioner 200 includes a mounting base 201, a heat sink 202, and a square prism 203 metal block; the square prism 203 is installed on the mounting base 201 through the heat sink 202,
  • the mounting base 201 is installed in the middle of the bottom surface of the mounting plate 100;
  • the mounting base 201 is provided with a control module 204, an LED drive modulation module 205 and an infrared receiving module 206, and the LED driving modulation module 205 and the infrared receiving module 206 are respectively Connected with the control module 204;
  • four first infrared receiving tubes 207 are arranged around the radiator 202, and the first infrared receiving tube 207 is connected with the infrared receiving module 206; All are provided with circuit substrates 208 (aluminum or copper), and each of the circuit substrates 208 is provided with a standard Lambertian radiation LED lamp 209, and the five described LED lamps 209 are respectively welded on the five circuit substrates 208;
  • the first infrared receiving tube 207 is used to receive the 3D position coordinate information sent by the user;
  • the LED drive modulation module 205 is used to drive the LED lights 209 in different orientations to send out frequency shift keying switch signals of different frequencies;
  • the The control module 204 is used for processing received infrared signals, generating LED driving signals, and performing serial bus communication between master and slave devices.
  • the automatic tracking optical communication device 300 includes a base 301, on which a horizontal rotation servo mechanism 302, a pitch rotation servo mechanism 303, and a beam projector 304 are installed in sequence;
  • the base 301 is provided with a data processing unit 305, a drive unit 306 and a communication signal processing unit 307, and the drive unit 306 and the communication signal processing unit 307 are respectively connected to the data processing unit 305;
  • the communication signal processing unit 307 has an Ethernet port and optical fiber port;
  • the output end of the beam projector 304 is provided with a light emitting device 308 (the present embodiment adopts a narrow beam LED device) and a second infrared receiving tube 309 (the present embodiment adopts a broadband infrared receiving tube), and the described
  • the light emitting device 308 and the second infrared receiving tube 309 are respectively connected to the data processing unit 305;
  • the light emitting device 308 is used for sending downlink broadband data, and the second infrared receiving tube 309 is
  • the beam projector 304 can also use a micro-vibration mirror or an optical phased array (Optical Phased Array, OPA) based on a micro-electro-mechanical system (Micro Electro Mechanical System, MEMS) in a lidar to adjust the beam angle , and then realize the real-time alignment function of the communication link.
  • OPA optical Phased Array
  • MEMS Micro Electro Mechanical System
  • the user receiver 400 includes a signal processing module, a photodiode 401 connected to the signal processing module (a high-speed photodiode is used in this embodiment), an infrared emission tube 402 and a distance measuring probe 403; the photodiode 401 Used to receive the optical signal emitted by the visible light locator 200 and the automatic tracking optical communication device 300; the infrared emitting tube 402 is used to send infrared signals to the visible light locator 200 and the automatic tracking optical communication device 300; the distance measuring probe 403 is used for To measure the vertical distance between the user (the user receiver 400 of this embodiment is connected to the user terminal 500 through a data interface) terminal and the ceiling or the ground, if the user terminal 500 is inclined, the inclination angle can be measured by the inertial sensor in the user terminal 500 , and then correct the vertical distance; the signal processing module is used for processing and receiving signals, and generating modulated signals.
  • the signal processing module is used for processing and receiving signals, and generating modulated signals.
  • This embodiment also provides a multi-user optical communication method assisted by visible light positioning, including the following steps:
  • the visible light locator 200 cyclically broadcasts the VLC micro-base station ID and the current working status identification data of the automatic tracking optical communication device 300 towards its coverage area;
  • the current working status identification data of the automatic tracking optical communication device 300 uses Bit data representation; in the present embodiment, adopt 8 bits " 10010110 " of a byte to represent the current working state of 8 automatic tracking optical communication devices 300, and the first "0" represents No. 1 automatic tracking optical communication device 300 is currently in the idle state; the second bit "1" indicates that the No. 2 automatic tracking optical communication device 300 is currently in the occupied state, that is, it indicates the frequency resource occupancy identifier between the automatic tracking optical communication device 300 and the UE.
  • the user receiver 400 After the user receiver 400 receives the VLC micro-base station ID and the current working state identification data of the automatic tracking optical communication device 300, according to the current working state identification data, select an unoccupied frequency resource as a carrier, and send the signal to the visible light locator 200 Upload the user's 3D position coordinates and identity (User Identification, UID);
  • the automatic tracking optical communication device 300 After the automatic tracking optical communication device 300 receives the user's 3D position coordinates, it converts them into pitch angle and rotation angle through analysis and calculation, and then sends them to the corresponding automatic tracking optical communication device 300 to control the horizontal rotation servo
  • the mechanism 302 and the pitch rotation servo mechanism 303 adjust the horizontal direction and pitch angle of the beam projector 304, so that the beam projector 304 is aligned with the user receiver 400, and send a channel estimation signal to the user receiver 400;
  • the user receiver 400 After receiving the channel estimation signal, the user receiver 400 evaluates whether the channel meets the broadband communication requirement, and if so, starts broadband data transmission; if not, rechecks.
  • the visible light locator 200 first obtains the 3D position coordinates of all idle automatic tracking optical communication devices 300, and then selects the automatic tracking optical communication device 300 closest to the user's 3D position coordinates; after establishing the communication link , analyze whether this communication link overlaps with other working communication links, if overlapping, then select the adjacent automatic tracking optical communication device 300 and user receiver 400 to re-establish the communication link until the re-established communication link overlaps with other Active communication links do not overlap.
  • an inertial sensor is installed in the user receiver 400. If the user receiver 400 shakes greatly, and the shaking value exceeds a set threshold, the user receiver 400 will re-estimate its own 3D position coordinates and send a new 3D position coordinates uploaded to the visible light locator 200, and the visible light locator 200 transmits the new 3D position coordinates to the automatic tracking optical communication device 300, and the automatic tracking optical communication device 300 corrects the beam projector 304 in real time according to the new 3D position coordinates The horizontal direction and pitch angle of the beam projector 304 are always aimed at the user receiver 400 .
  • the stereoscopic 3D unit normal vector of the i-th LED light is defined as:
  • the 3D coordinate vector of the PD (photodetector) on the receiver user equipment (User Equipment, UE) is defined as:
  • the unit normal vector of PD (photodetector) is defined as: n U
  • the 3D direction vector from the LED light position to the UE position is:
  • the radiation angle between the i-th LED relative to the UE is defined as ⁇ i , then:
  • the incident angle of UE relative to the i-th LED is defined as Then there are:
  • the light intensity of the light signal of the i-th LED wick reaching the UE through visible propagation can be expressed as:
  • ⁇ U is the response coefficient of PD
  • PL is the radiation light power of LED
  • n is the Lambertian radiation lobe modulus (representing the directionality of the light source)
  • m is the order of PD
  • AU is the receiving area of PD
  • F i is the indicator function, when the function is in takes the value 1 when , and takes the value 0 in other cases, where Indicates the field of view of the PD;
  • the present invention proposes a method for quickly estimating the 3D position coordinates of the user receiver, the steps are as follows:
  • the eigenvalues are sorted from small to large, and the eigenvector corresponding to the smallest eigenvalue is obtained.
  • This eigenvector is the optimal solution of the 3D normalized relative coordinates from the visible light locator to the UE, expressed as
  • the receiver uses the ranging probe and the inertial sensor to obtain the distance from the UE to the ceiling or the floor, and further obtains the vertical distance h D from the UE to the visible light locator;
  • the fourth step through the formula
  • the three-dimensional coordinates U of the UE are estimated, where [x L , y L , z L ] are the 3D coordinates of the visible light locator.
  • the parameter setting in Table 1 below is taken as an example to analyze and verify the three-dimensional coordinate position method based on the square prism visible light locator proposed in this embodiment. It should be pointed out that the method for quickly estimating three-dimensional coordinates proposed by the present invention is also applicable to visible light locators based on other positive N-prisms.
  • the five LED lights of the visible light locator send FSK switch signals of different frequencies through the triode or FET switch control circuit, and the frequency configuration of the five LED lights is shown in Table 2 below.
  • the A/D sampling frequency of the user receiver is set to 96kHz, the number of sampling window points is set to 9600, and the user receiver adopts the Goetzel algorithm to extract the light intensity spectrum amplitude emitted by 5 LED lamps.
  • the VLC micro base station is installed on the ceiling in the middle of a room with a length, width, and height of 10m ⁇ 10m ⁇ 5m. As shown in Figure 6, the height of the UE held by the user from the floor is set to 1.2m. This height can be determined by the distance detector in the UE. get.
  • the simulation results in Figure 7 show that the proposed visible light positioning structure and algorithm can support small-angle tilt and azimuth random adjustment of UE terminals.
  • the tilt angle (polarization angle) ⁇ [-20°, 20°] the average positioning error At about 4 cm, it can effectively meet the functional requirements of the proposed system.
  • the tilt angle of the UE is too large, a large part of the area can still meet the functional requirements, and in some positions, the sharp deterioration of the LE can be alleviated through further optimization.
  • the embodiments of the present application may be provided as methods, systems or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • a computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to operate in a specific manner, such that the instructions stored in the computer-readable memory produce an article of manufacture comprising instruction means, the instructions
  • the device realizes the function specified in one or more procedures of the flowchart and/or one or more blocks of the block diagram.

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Abstract

一种可见光定位辅助的多用户光通信系统及方法，通信系统包括微基站和用户接收机（400）；微基站包括安装板（100），安装板（100）的底面中部设有可见光定位器（200），安装板（100）的底面围绕可见光定位器（200）设有若干个自动跟踪光通信装置（300）；可见光定位器（200）通过串行总线与多个自动跟踪光通信装置（300）连接；可见光定位器（100）向覆盖区域循环广播微基站ID和自动跟踪光通信装置（300）的当前工作状态数据；用户接收机（400）向可见光定位器（200）发送自身3D位置坐标和用户身份标识；可见光定位器（200）指定离用户最近且空闲的自动跟踪光通信装置（300）与用户接收机（400）建立通信链路。可有效解决光通信的点到面或立体空间的辐射通信质量差、误码率高的瓶颈问题。

Description

一种可见光定位辅助的多用户光通信系统及方法 技术领域
本发明属于可见光通信技术领域，具体涉及一种可见光定位辅助的多用户光通信系统及方法。
背景技术
可见光通信(Visible Light Communication，VLC)由于具有频谱无须授权、高安全保密性、400～800THz的超宽频谱和无电磁辐射等优点，被业界认为是无线个人局域网(Wireless Personal Area Network,WPAN)通讯技术的一个替代技术，有望在下一代6G、7G甚至8G通信场景中得到广泛的应用。目前，VLC的发射器件主要采用发光二极管(Light Emitted Diode，LED)、激光二极管(Laser Diode，LD)和最新研发的超辐射二极管(SLD)，接收器件通常采用光电二极管(PIN)、雪崩二极管(APD)和图像传感器等。
通常，LED采用自发辐射模式，发出的光为非相干光，光谱宽，发射方向为全向发射，总输出功率可以较高，然而由于发射角度大，因此光功率密度低。LD采用放大受激辐射模式，发出的光为相干光，光谱窄，发射方向指向性强，输出功率可以较高，光功率密度高。目前，实验验证的VLC系统的主要结构仍然为点对点通信，如果采用LED，则需要在LED前端加装一个聚光透镜，用来形成平行光束，同时在接收端加装一个凸透镜，使光汇聚在光电检测器(Photo Detector，PD)的表面上。这样做的好处是有效提高了LED的光功率密度，使得接收机的信噪比大大提升，从而大大降低通信的误码率，进而提高通信质量。
然而，这种点对点VLC系统如果应用在实际的WPAN场景中会面临一些瓶颈性问题。通常，在WPAN场景中，一个微基站会同时为多个用户服务，因此要求如同WiFi一样，能够实现一个点到面、甚至点到立体空间的全向辐射通信，而VLC微基站如果采用LED，虽然也能够实现点对面的覆盖，但是LED辐射功率密度低，导致PD接收到的信号微弱，信噪比低，影响通信质量。此时为了提高通信质量，我们只能增加LED的辐射光功率，但是这会直接导致基站的耗能过大，同时照明过亮，用户体验差。如果VLC微基站采用LD，由于其方向性强，我们可以采用毫瓦级的LD实施点对点通信，可有效节省能耗。但是问题在于，如何与地面上的随机位置用户建立实时的点对点通信链路是一瓶颈问题。
如公开号为CN113162688A的中国专利公开了一种可见光双向通信与定位系统，包括 第一通信节点和第二通信节点，第一通信节点包括定位光源、第一通信光源、PIN/APD探测器模组以及驱动第一通信光源和PIN/APD探测器模组转动的第一驱动装置组件；第二通信节点包括复合接收机、第二通信光源和驱动第二通信光源转动的第二驱动装置；复合接收机用于接收定位光源和第一通信光源的信号，复合接收机包括多个探测器；PIN/APD探测器模组用于接收第二通信光源的信号。系统通过两个通信节点能够实现可见光波段内两个通信节点同时上传和下载数据，并能够实现定位跟踪功能，以实现两个通信节点即使发生相对运动也能保持第一通信光源与复合接收机以及第二通信光源与PIN/APD探测器模组的对准，保证通信质量。该专利能够实时定位跟踪节点的位置信息，实现两个通信节点的实时对准，保证了可见光通信的可靠性和稳定性。
然而，该专利虽然能够实现点对点的通信，且能够实现定位跟踪功能，但其实现定位的原理与本申请存在较大差别。
发明内容
本发明的目的是针对现有技术存在的VLC微基站与随机位置上的多个用户的点对点通信链路连接问题，提供一种可见光定位辅助的多用户光通信系统及方法，该系统能够同时为多个用户提供宽带传输服务，相互干扰小，具有较好的应用价值。
为实现上述目的，本发明采用的技术方案是：
一种可见光定位辅助的多用户光通信系统，包括VLC微基站和用户接收机；所述VLC微基站包括安装板，所述安装板的底面中部设有可见光定位器，所述安装板的底面围绕可见光定位器设有若干个自动跟踪光通信装置；所述可见光定位器通过串行总线与多个自动跟踪光通信装置连接，从而实现主从设备的双向通信，其中可见光定位器为主设备，自动跟踪光通信装置为从设备；所述可见光定位器向覆盖区域循环广播VLC微基站ID和自动跟踪光通信装置的当前工作状态数据；所述用户接收机向可见光定位器发送自身3D位置坐标和用户身份标识；所述可见光定位器根据用户的3D位置坐标和身份标识，指定离用户最近且空闲的自动跟踪光通信装置与用户接收机建立通信链路。
具体地，所述可见光定位器包括安装座、散热器和正N棱台，N≥3，且N∈Z +；所述正N棱台通过散热器安装在安装座上，所述安装座安装在安装板的底面中部；所述安装座内设有控制模块、LED驱动调制模块和红外接收模块，所述LED驱动调制模块、红外接收模块分别与控制模块连接；所述散热器的周围设有若干个第一红外接收管，所述第一红外接收管与红外接收模块连接；所述正N棱台的N+1个面上均设有线路基板，每个所述线路基板上均设有一个LED灯，所述LED灯通过线路基板与LED驱动调制模块连接；所 述第一红外接收管用于接收用户发送的3D位置坐标信息；所述LED驱动调制模块用于驱动不同朝向的LED灯发出不同频率的频移键控开关信号；所述控制模块用于处理接收到的红外信号以及生成LED驱动信号。
具体地，所述自动跟踪光通信装置包括底座，所述底座上安装有依次连接的水平旋转伺服机构、俯仰旋转伺服机构和光束投射器；所述底座内设有数据处理单元、驱动单元和通信信号处理单元，所述驱动单元、通信信号处理单元分别与数据处理单元连接；所述通信信号处理单元引出有以太网端口和光纤端口；所述以太网端口连接到室内的光纤猫上，或者光纤端口连接室内光纤；这两个网络端口连接公网或移动通信网。所述光束投射器的输出端设有光发射器件和第二红外接收管，所述光发射器件、第二红外接收管分别与数据处理单元连接；所述光发射器件用于下行链路宽带数据的发送，所述第二红外接收管用于上行链路宽带数据的接收；所述驱动单元用于驱动水平旋转伺服机构和俯仰旋转伺服机构调整光束投射器的水平方向和俯仰角度；所述数据处理单元用于处理可见光定位器发送的数据，并生成目标追踪信号给驱动单元。
具体地，所述用户接收机包括信号处理模块、与所述信号处理模块连接的光电二极管、红外发射管和测距探头；所述光电二极管用于接收可见光定位器和自动跟踪光通信装置发射的光信号；所述红外发射管用于向可见光定位器和自动跟踪光通信装置发送红外信号；所述测距探头用于测量自身的高度数据；所述信号处理模块用于处理、接收信号，并产生调制信号。
与上述光通信系统对应的，本发明还提出了一种可见光定位辅助的多用户光通信方法，包括以下步骤：
S1，可见光定位器朝其覆盖区域循环广播VLC微基站ID和自动跟踪光通信装置的当前工作状态标识数据；
S2，用户接收机接收到VLC微基站ID和自动跟踪光通信装置的当前工作状态标识数据后，根据所述当前工作状态标识数据，选用未被占用的频率资源作为载波，向可见光定位器上传用户的3D位置坐标和身份标识；
S3，可见光定位器接收到所述3D位置坐标和身份标识后，指定离用户最近且空闲的自动跟踪光通信装置与用户接收机建立通信链路，并将用户的3D位置坐标和身份标识通过串行总线传输给对应的自动跟踪光通信装置；
S4，所述自动跟踪光通信装置根据用户的3D位置坐标，调整自身光束投射器的水平方向和俯仰角，使所述光束投射器对准用户接收机，并向用户接收机发送信道估计信号；
S5，用户接收机接收到所述信道估计信号后，评估该信道是否达到宽带通信要求，若达到，则开始进行宽带数据传输；若未达到，则进行重检。
具体地，步骤S3中，所述可见光定位器首先获取所有空闲自动跟踪光通信装置的3D位置坐标，再从中选取离用户3D位置坐标最近的自动跟踪光通信装置；建立通信链路后，分析该通信链路是否与其它正在工作的通信链路重叠，若重叠，则选择临近的自动跟踪光通信装置与用户接收机重新建立通信链路，直到重新建立的通信链路与其它正在工作的通信链路不重叠。
进一步地，如果在空闲自动跟踪光通信装置中找不到合适的通信链路，可通过分析调度，将已工作的通信链路迁移至不造成光束重叠的空闲自动跟踪光通信装置上，让出空间通信链路给新接入用户，最大限度地保证各通信链路不重叠。
具体地，所述用户接收机内安装有惯性传感器，若用户接收机有大幅度晃动，且晃动值超过设定阈值，则用户接收机会重新估算自身的3D位置坐标，并将新的3D位置坐标上传可见光定位器，可见光定位器再将该新的3D位置坐标传输给自动跟踪光通信装置，自动跟踪光通信装置根据该新的3D位置坐标实时校正光束投射器的水平方向和俯仰角，使光束投射器的投射方向始终对准用户接收机。
具体地，获取用户的3D位置坐标，首先要定义以下参数：
由于N+1个不同朝向的LED灯的位置相距若干毫米，很接近，因此近似假定N+1个LED灯的3D坐标位置相同，LED灯的3D坐标向量统一定义为：
S＝[x L,y L,z L] T
第i颗LED灯的立体3D单位法向量定义为：
Figure PCTCN2022082159-appb-000001
接收机用户设备(User Equipment，UE)上的PD(光电检测器)的3D坐标向量定义为：
U＝[x U,y U,z U] T
PD(光电检测器)的单位法向量定义为：n U
从LED灯位置到UE位置的3D方向向量为：
d＝U-S＝[x U-x L,y U-y L,z U-z L] T
LED灯到UE之间的距离为：d＝||d|| 2
第i颗LED相对于UE之间的辐射角定义为φ i，则有：
Figure PCTCN2022082159-appb-000002
UE相对于第i颗LED的入射角定义为
Figure PCTCN2022082159-appb-000003
则有：
Figure PCTCN2022082159-appb-000004
第i颗LED灯芯的光信号经过可视传播到达UE的光强可表示为：
Figure PCTCN2022082159-appb-000005
其中β U为PD的响应系数，P L为LED的辐射光功率，n为朗伯辐射波瓣模数(代表光源的方向性)，m为PD的阶数，A U为PD的接收面积，F i为指示函数，当该函数在
Figure PCTCN2022082159-appb-000006
时取值为1，其它情况时取值为0，其中
Figure PCTCN2022082159-appb-000007
表示PD的视场角；
令
Figure PCTCN2022082159-appb-000008
则有：
Figure PCTCN2022082159-appb-000009
将接受到的来自不同LED的光强两两相除，得到接收强度比例值α i,j，根据式(2)可写为：
Figure PCTCN2022082159-appb-000010
进一步地，令x D＝x L-x U,y D＝y L-y U,z D＝z L-z U，U D＝[x D,y D,z D]可视为UE相对于可见光定位器的相对3D坐标，则式(3)可写为：
Figure PCTCN2022082159-appb-000011
式(4)进一步可写成一齐次线性方程组AX＝0的形式，其中
Figure PCTCN2022082159-appb-000012
Figure PCTCN2022082159-appb-000013
根据以上定义，本发明提出一种快速估计用户接收机3D位置坐标的方法，步骤如下:
第一步，计算出正交矩阵B＝A TA的特征值和特征向量，其中B为3×3矩阵；
第二步，对特征值按由小到大进行排序，获取最小特征值对应的特征向量，该特征向量为可见光定位器到UE的3D归一化相对坐标最优解，表示为
Figure PCTCN2022082159-appb-000014
第三步，接收机使用测距探头和惯性传感器获取UE到天花板或地板的距离，进一步得到UE到可见光定位器的垂直距离h D；
第四步，通过公式
Figure PCTCN2022082159-appb-000015
估算出UE的三维坐标U，其中[x L,y L,z L]为可见光定位器的3D坐标。
与现有技术相比，本发明的有益效果是：本发明将一个可见光定位器与多个自动跟踪光通信装置通过串行总线连接，根据用户的实际3D位置坐标为用户匹配最合适的自动跟踪光通信装置，可有效解决光通信的点到面或立体空间的辐射通信质量差、误码率高的瓶颈问题；(2)本发明每个自动跟踪光通信装置与用户设备之间仍是采用点对点通信，大大节省了发射设备的功率能耗；(3)本发明各个通信链路之间采用了空间上的光束隔离，不同用户之间的信息传输干扰小，进一步提升了通信质量。
附图说明
图1为本发明实施例中一种可见光定位辅助的多用户光通信系统的结构示意图。
图2为本发明实施例中可见光定位器的倒置主视图。
图3为本发明实施例中可见光定位器的侧视图。
图4为本发明实施例中自动跟踪光通信装置的结构示意图。
图5为本发明实施例中可见光定位器的平面简化示意图。
图6为本发明实施例中光通信系统的应用场景配置图。
图7为本发明实施例中定位误差性能仿真三维分布示意图。
图中：100、安装板；200、可见光定位器；201、安装座；202、散热器；203、正四棱台；204、控制模块；205、LED驱动调制模块；206、红外接收模块；207、第一红外接收管；208、线路基板；209、LED灯；300、自动跟踪光通信装置；301、底座；302、水平旋转伺服机构；303、俯仰旋转伺服机构；304、光束投射器；305、数据处理单元；306、驱动单元；307、通信信号处理单元；308、光发射器件；309、第二红外接收管；400、用户接收机；401、光电二极管；402、红外发射管；403、测距探头；500、用户终端。
具体实施方式
下面将结合本发明中的附图，对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动条件下所获得的所有其它实施例，都属于本发明保护的范围。
如图1所示，本实施例提供了一种可见光定位辅助的多用户光通信系统，包括VLC微基站和用户接收机400；所述VLC微基站包括安装板100，所述安装板100的底面中部设有可见光定位器200，所述安装板100的底面围绕可见光定位器200等间隔设有8个自动跟踪光通信装置300；所述可见光定位器200通过串行总线与8个自动跟踪光通信装置300连接，从而实现主从设备的双向通信，其中可见光定位器200为主设备，自动跟踪光通信装置300为从设备；所述可见光定位器200向覆盖区域循环广播VLC微基站ID和自动跟踪光通信装置300的当前工作状态数据；所述用户接收机400向可见光定位器200发送自身3D位置坐标和用户身份标识；所述可见光定位器200根据用户的3D位置坐标和身份标识，指定离用户最近且空闲的自动跟踪光通信装置300与用户接收机400建立通信链路。
具体地，如图2、3所示，所述可见光定位器200包括安装座201、散热器202和正四棱台203金属块；所述正四棱台203通过散热器202安装在安装座201上，所述安装座201安装在安装板100的底面中部；所述安装座201内设有控制模块204、LED驱动调制模块205和红外接收模块206，所述LED驱动调制模块205、红外接收模块206分别与控制模块204连接；所述散热器202的周围设有4个第一红外接收管207，所述第一红外接收管207与红外接收模块206连接；所述正四棱台203的5个面上均设有线路基板208(铝或铜)， 每个所述线路基板208上均设有一个标准朗伯辐射LED灯209，5个所述LED灯209分别焊接在5个线路基板208上；所述LED灯209通过线路基板208与LED驱动调制模块205连接；所述第一红外接收管207的高度略高于LED灯209，避免LED灯209发出的信号影响第一红外接收管207接收的红外信号；所述第一红外接收管207用于接收用户发送的3D位置坐标信息；所述LED驱动调制模块205用于驱动不同朝向的LED灯209发出不同频率的频移键控开关信号；所述控制模块204用于处理接收到的红外信号、生成LED驱动信号以及进行主从设备串行总线通信。
具体地，如图4所示，所述自动跟踪光通信装置300包括底座301，所述底座301上安装有依次连接的水平旋转伺服机构302、俯仰旋转伺服机构303和光束投射器304；所述底座301内设有数据处理单元305、驱动单元306和通信信号处理单元307，所述驱动单元306、通信信号处理单元307分别与数据处理单元305连接；所述通信信号处理单元307引出有以太网端口和光纤端口；所述光束投射器304的输出端设有光发射器件308(本实施例采用窄光束LED器件)和第二红外接收管309(本实施例采用宽带红外接收管)，所述光发射器件308、第二红外接收管309分别与数据处理单元305连接；所述光发射器件308用于下行链路宽带数据的发送，所述第二红外接收管309用于上行链路宽带数据的接收；所述驱动单元306用于驱动水平旋转伺服机构302和俯仰旋转伺服机构303分别进行0～360°水平旋转和0～90°竖直旋转，以调整光束投射器304的水平方向和俯仰角度，从而能使窄光束LED器件的光束始终对准用户接收机400。所述数据处理单元305用于处理可见光定位器200发送的数据，并生成目标追踪信号给驱动单元306。
本实施例中，所述光束投射器304也可采用激光雷达中的基于微机电系统(Micro Electro Mechanical System,MEMS)的微振镜或光学相控阵(Optical Phased Array,OPA)来调整光束角度，进而实现通信链路实时对准功能。
具体地，所述用户接收机400包括信号处理模块、与所述信号处理模块连接的光电二极管401(本实施例采用高速光电二极管)、红外发射管402和测距探头403；所述光电二极管401用于接收可见光定位器200和自动跟踪光通信装置300发射的光信号；所述红外发射管402用于向可见光定位器200和自动跟踪光通信装置300发送红外信号；所述测距探头403用于测量用户(本实施例的用户接收机400与用户终端500通过数据接口连接)终端与天花板或地面的垂直距离，如果用户终端500是倾斜的，可通过用户终端500内的惯性传感器测量倾斜角度，然后修正垂直距离；所述信号处理模块用于处理、接收信号，并产生调制信号。
本实施例还提供了一种可见光定位辅助的多用户光通信方法，包括以下步骤：
S1，可见光定位器200朝其覆盖区域循环广播VLC微基站ID和自动跟踪光通信装置300的当前工作状态标识数据；所述自动跟踪光通信装置300的当前工作状态标识数据采用几个字节的比特数据表示；本实施例中，采用一个字节的8位比特“10010110”来表示8个自动跟踪光通信装置300的当前工作状态，第1位“0”表示第1号自动跟踪光通信装置300当前处于空闲状态；第2位“1”表示第2号自动跟踪光通信装置300当前处于占用状态，即表示该自动跟踪光通信装置300与UE之间的频率资源占用标识。
S2，用户接收机400接收到VLC微基站ID和自动跟踪光通信装置300的当前工作状态标识数据后，根据所述当前工作状态标识数据，选用未被占用的频率资源作为载波，向可见光定位器200上传用户的3D位置坐标和身份标识(User Identification，UID)；
S3，可见光定位器200接收到所述3D位置坐标和身份标识后，指定离用户最近且空闲的自动跟踪光通信装置300与用户接收机400建立通信链路，并将用户的3D位置坐标和身份标识通过串行总线传输给对应的自动跟踪光通信装置300；
S4，所述自动跟踪光通信装置300接收到用户的3D位置坐标后，通过分析计算将其转换成俯仰角和旋转角，然后将其发送给对应的自动跟踪光通信装置300，控制水平旋转伺服机构302和俯仰旋转伺服机构303调整光束投射器304的水平方向和俯仰角，使所述光束投射器304对准用户接收机400，并向用户接收机400发送信道估计信号；
S5，用户接收机400接收到所述信道估计信号后，评估该信道是否达到宽带通信要求，若达到，则开始进行宽带数据传输；若未达到，则进行重检。
具体地，步骤S3中，所述可见光定位器200首先获取所有空闲自动跟踪光通信装置300的3D位置坐标，再从中选取离用户3D位置坐标最近的自动跟踪光通信装置300；建立通信链路后，分析该通信链路是否与其它正在工作的通信链路重叠，若重叠，则选择临近的自动跟踪光通信装置300与用户接收机400重新建立通信链路，直到重新建立的通信链路与其它正在工作的通信链路不重叠。
具体地，所述用户接收机400内安装有惯性传感器，若用户接收机400有大幅度晃动，且晃动值超过设定阈值，则用户接收机400会重新估算自身的3D位置坐标，并将新的3D位置坐标上传可见光定位器200，可见光定位器200再将该新的3D位置坐标传输给自动跟踪光通信装置300，自动跟踪光通信装置300根据该新的3D位置坐标实时校正光束投射器304的水平方向和俯仰角，使光束投射器304的投射方向始终对准用户接收机400。
具体地，如图5所示，为了获取用户的3D位置坐标，首先要定义以下参数：
由于5个不同朝向的LED灯的位置相距若干毫米，很接近，因此近似假定5个LED灯的3D坐标位置相同，LED灯的3D坐标向量统一定义为：
S＝[x L,y L,z L] T
第i颗LED灯的立体3D单位法向量定义为：
Figure PCTCN2022082159-appb-000016
接收机用户设备(User Equipment，UE)上的PD(光电检测器)的3D坐标向量定义为：
U＝[x U,y U,z U] T
PD(光电检测器)的单位法向量定义为：n U
从LED灯位置到UE位置的3D方向向量为：
d＝U-S＝[x U-x L,y U-y L,z U-z L] T
LED灯到UE之间的距离为：d＝||d|| 2
第i颗LED相对于UE之间的辐射角定义为φ i，则有：
Figure PCTCN2022082159-appb-000017
UE相对于第i颗LED的入射角定义为
Figure PCTCN2022082159-appb-000018
则有：
Figure PCTCN2022082159-appb-000019
第i颗LED灯芯的光信号经过可视传播到达UE的光强可表示为：
Figure PCTCN2022082159-appb-000020
其中β U为PD的响应系数，P L为LED的辐射光功率，n为朗伯辐射波瓣模数(代表光源的方向性)，m为PD的阶数，A U为PD的接收面积，F i为指示函数，当该函数在
Figure PCTCN2022082159-appb-000021
时取值为1，其它情况时取值为0，其中
Figure PCTCN2022082159-appb-000022
表示PD的视场角；
令
Figure PCTCN2022082159-appb-000023
则有：
Figure PCTCN2022082159-appb-000024
将接受到的来自不同LED的光强两两相除，得到接收强度比例值α i,j，根据式(2)可写为：
Figure PCTCN2022082159-appb-000025
进一步地，令x D＝x L-x U,y D＝y L-y U,z D＝z L-z U，U D＝[x D,y D,z D]可视为UE相对于可见光定位器的相对3D坐标，则式(3)可写为：
Figure PCTCN2022082159-appb-000026
式(4)进一步可写成一齐次线性方程组AX＝0的形式，其中
Figure PCTCN2022082159-appb-000027
Figure PCTCN2022082159-appb-000028
根据以上定义，本发明提出一种快速估计用户接收机3D位置坐标的方法，步骤如下:
第一步，计算出正交矩阵B＝A TA的特征值和特征向量，其中B为3×3矩阵；
第二步，对特征值按由小到大进行排序，获取最小特征值对应的特征向量，该特征向量为可见光定位器到UE的3D归一化相对坐标最优解，表示为
Figure PCTCN2022082159-appb-000029
第三步，接收机使用测距探头和惯性传感器获取UE到天花板或地板的距离，进一步得到UE到可见光定位器的垂直距离h D；
第四步，通过公式
Figure PCTCN2022082159-appb-000030
估算出UE的三维坐标U，其中[x L,y L,z L]为可见光定位器的3D坐标。
本实施例以下表1参数设置为例，对本实施例提出的基于正四棱台可见光定位器的三维坐标位置方法进行分析和仿真验证。需要指出的是，本发明提出的快速估算三维坐标方法，也适用于基于其它正N棱台的可见光定位器。
表1仿真使用参数
Figure PCTCN2022082159-appb-000031
所述可见光定位器的5颗LED灯通过三极管或场效应管开关控制电路发出不同频率的频移键控开关信号，5颗LED灯的频率配置如下表2所示。
表2 LED灯频率配置
Figure PCTCN2022082159-appb-000032
Figure PCTCN2022082159-appb-000033
所述用户接收机的A/D采样频率设置为96kHz，采样窗口点数设置为9600，用户接收机采用戈泽尔算法提取5颗LED灯发出的光强谱幅度。在本实施例中，5颗LED灯的朝向法向量分别为：n 0＝[0,0,-1]，n 1＝[sinθ,0,-cosθ]，n 2＝[0,sinθ,-cosθ]，n 3＝[-sinθ,0,-cosθ]和n 4＝[0,-sinθ,-cosθ]。VLC微基站安装在一个长宽高为10m×10m×5m的房间中间天花板上，如图6所示，用户手持UE离地板的高度设定为1.2m，此高度可通过UE内的距离探测器获得。
图7为本实施例的定位误差(Location Error,LE)性能仿真三维分布图，从图7(a)(b)中可观察到当UE终端的PD平放时，即α＝0°时，不管UE方位角β如何变化，本实施例中的定位算法的平均定位误差(Location Error,LE)在3.66厘米左右，而最大LE在12.7厘米左右。从图7(c)(d)中可观察到当UE终端的PD向上倾斜20度时，即α＝20°时，不管UE方位角β如何变化，系统所提定位算法的平均定位误差(Location Error,LE)在3.75厘米左右，而最大LE在16.6厘米左右，相较PD平方，倾斜20度的定位性能稍微下降，但变化不大。从图7(e)(f)中可观察到当UE终端的PD向上倾斜40度时，即α＝40°时，UE在大部分区域内的LE均在5厘米以内，而在某一些边缘区域，其LE迅速恶化，定位误差极大。出现该现象的原因为，当UE倾斜角度过大后，会导致在某一些方位角和位置上出现接收不到某一颗或两颗LED发射的光信号，从而引发不能正常的提取谱幅度，谱幅度失真大或极微弱，最终导致LE极大。解决这种现象的方法，可以进一步考虑剔除这些异常谱幅度，让其不参与定位算法处理。进一步地，从图7(g)(h)中可观察到当UE终端的PD向下倾斜30度时，所得到的平均LE在3.94厘米左右，而在某一些边缘区域，其LE误差较大，但不超过60厘米。
图7仿真结果表明所提的可见光定位结构和算法能够支持UE终端的小角度倾斜和方位角随机调整，当倾斜角(极化角)β∈[-20°，20°]时，平均定位误差在4厘米左右，能够有效的满足所提系统的功能需求。而当UE的倾斜角过大时，仍然有很大一部分区域能够满足功能需求，而在某一些位置，可通过进一步优化，来缓解LE的急剧恶化。
本须域内的技术人员应明白，本申请的实施例可提供为方法、系统或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施列的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品 的形式。
本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每--流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
尽管已经示出和描述了本发明的实施例，对于本领域的普通技术人员而言，可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行多种变化、修改、替换和变型，本发明的范围由所附权利要求及其等同物限定。

Claims (8)

  1. 一种可见光定位辅助的多用户光通信系统，其特征在于，包括微基站和用户接收机；所述微基站包括安装板，所述安装板的底面中部设有可见光定位器，所述安装板的底面围绕可见光定位器设有若干个自动跟踪光通信装置；所述可见光定位器通过串行总线与多个自动跟踪光通信装置连接；所述可见光定位器向覆盖区域循环广播微基站ID和自动跟踪光通信装置的当前工作状态数据；所述用户接收机向可见光定位器发送自身3D位置坐标和用户身份标识；所述可见光定位器根据用户的3D位置坐标和身份标识，指定离用户最近且空闲的自动跟踪光通信装置与用户接收机建立通信链路。
  2. 根据权利要求1所述的一种可见光定位辅助的多用户光通信系统，其特征在于，所述可见光定位器包括安装座、散热器和正N棱台，N≥3，且N∈Z +；所述正N棱台通过散热器安装在安装座上，所述安装座安装在安装板的底面中部；所述安装座内设有控制模块、LED驱动调制模块和红外接收模块，所述LED驱动调制模块、红外接收模块分别与控制模块连接；所述散热器的周围设有若干个第一红外接收管，所述第一红外接收管与红外接收模块连接；所述正N棱台的N+1个面上均设有线路基板，每个所述线路基板上均设有一个LED灯，所述LED灯通过线路基板与LED驱动调制模块连接；所述第一红外接收管用于接收用户发送的3D位置坐标信息；所述LED驱动调制模块用于驱动LED灯发出不同频率的频移键控开关信号；所述控制模块用于处理接收到的红外信号以及生成LED驱动信号。
  3. 根据权利要求1所述的一种可见光定位辅助的多用户光通信系统，其特征在于，所述自动跟踪光通信装置包括底座，所述底座上安装有依次连接的水平旋转伺服机构、俯仰旋转伺服机构和光束投射器；所述底座内设有数据处理单元、驱动单元和通信信号处理单元，所述驱动单元、通信信号处理单元分别与数据处理单元连接；所述光束投射器的输出端设有光发射器件和第二红外接收管，所述光发射器件、第二红外接收管分别与数据处理单元连接；所述光发射器件用于下行链路宽带数据的发送，所述第二红外接收管用于上行链路宽带数据的接收；所述驱动单元用于驱动水平旋转伺服机构和俯仰旋转伺服机构调整光束投射器的水平方向和俯仰角度；所述数据处理单元用于处理可见光定位器发送的数据，并生成目标追踪信号给驱动单元。
  4. 根据权利要求1所述的一种可见光定位辅助的多用户光通信系统，其特征在于，所述用户接收机包括信号处理模块、与所述信号处理模块连接的光电二极管、红外发射管和测距探头；所述光电二极管用于接收可见光定位器和自动跟踪光通信装置发射的光信号；所述红外发射管用于向可见光定位器和自动跟踪光通信装置发送红外信号；所述测距 探头用于测量自身的高度数据；所述信号处理模块用于处理、接收信号，并产生调制信号。
  5. 一种快速估算用户接收机3D位置坐标的方法，基于权利要求2所述的一种可见光定位辅助的多用户光通信系统，其特征在于，包括以下步骤：
    第一步，计算出正交矩阵B＝A TA；其中：
    Figure PCTCN2022082159-appb-100001
    α i,j表示来自第i颗LED与第j颗LED灯的光强比例值，即
    Figure PCTCN2022082159-appb-100002
    其中I i和I j表示第i颗LED灯与第j颗LED灯的光强；
    Figure PCTCN2022082159-appb-100003
    和
    Figure PCTCN2022082159-appb-100004
    分别表示第i颗LED灯沿x轴、沿y轴和沿z轴的单位法向量，n表示LED灯的朗伯辐射波瓣模数；正交矩阵B为3×3矩阵；
    第二步，计算正交矩阵B的特征值和特征向量；
    第三步，对特征值按由小到大的顺序进行排序，获取最小特征值对应的特征向量，该特征向量表示可见光定位器到用户接收机的3D归一化相对坐标最优解，表示为
    Figure PCTCN2022082159-appb-100005
    第四步，用户接收机使用测距探头和惯性传感器获取自身到天花板或地板的距离，进一步得到用户接收机到可见光定位器的垂直距离h D；
    第五步，通过公式
    Figure PCTCN2022082159-appb-100006
    估算出用户接收机的三维坐标U，其中[x L,y L,z L]为可见光定位器的3D坐标。
  6. 一种可见光定位辅助的多用户光通信方法，基于权利要求1至5中任一项所述的可见光定位辅助的多用户光通信系统，其特征在于，包括以下步骤：
    S1，可见光定位器朝其覆盖区域循环广播微基站ID和自动跟踪光通信装置的当前工作状态标识数据；
    S2，用户接收机接收到微基站ID和自动跟踪光通信装置的当前工作状态标识数据后， 根据所述当前工作状态标识数据，选用未被占用的频率资源作为载波，向可见光定位器上传用户的3D位置坐标和身份标识；
    S3，可见光定位器接收到所述3D位置坐标和身份标识后，指定离用户最近且空闲的自动跟踪光通信装置与用户接收机建立通信链路，并将用户的3D位置坐标和身份标识通过串行总线传输给对应的自动跟踪光通信装置；
    S4，所述自动跟踪光通信装置根据用户的3D位置坐标，调整自身光束投射器的水平方向和俯仰角，使所述光束投射器对准用户接收机，并向用户接收机发送信道估计信号；
    S5，用户接收机接收到所述信道估计信号后，评估该信道是否达到宽带通信要求，若达到，则开始进行宽带数据传输；若未达到，则进行重检。
  7. 根据权利要求6所述的一种可见光定位辅助的多用户光通信方法，其特征在于，步骤S3中，所述可见光定位器首先获取所有空闲自动跟踪光通信装置的3D位置坐标，再从中选取离用户3D位置坐标最近的自动跟踪光通信装置；建立通信链路后，分析该通信链路是否与其它正在工作的通信链路重叠，若重叠，则选择临近的自动跟踪光通信装置与用户接收机重新建立通信链路，直到重新建立的通信链路与其它正在工作的通信链路不重叠；如果在空闲自动跟踪光通信装置中找不到合适的通信链路，可通过分析调度，将已工作的通信链路迁移至不造成光束重叠的空闲自动跟踪光通信装置上，让出空间通信链路给新接入用户，最大限度地保证各通信链路不重叠。
  8. 根据权利要求6所述的一种可见光定位辅助的多用户光通信方法，其特征在于，所述用户接收机内安装有惯性传感器，若用户接收机有大幅度晃动，且晃动值超过设定阈值，则用户接收机会重新估算自身的3D位置坐标，并将新的3D位置坐标上传可见光定位器，可见光定位器再将该新的3D位置坐标传输给自动跟踪光通信装置，自动跟踪光通信装置根据该新的3D位置坐标实时校正光束投射器的水平方向和俯仰角，使光束投射器的投射方向始终对准用户接收机。
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