Visible light communication and location sensing integrated system based on active illumination and computational reconstruction

Abstract

The present invention belongs to the field of optical wireless communication technology, specifically, a visible light communication and position perception integrated system based on active illumination and computational reconstruction. The system of the present invention includes a light source module, a spatial light modulator, a single-pixel photodetector, a communication signal processing unit, and a control unit: the light source module is used to generate illumination light for visible light communication signals; the spatial light modulator is used to modulate the spatial distribution of the light field of the light signal; the single-pixel photodetector is used to receive the light signal modulated by the spatial light modulator and then convert it into an electrical signal; the communication signal processing unit is used to restore the original communication signal and reconstruct the spatial position information from the timing signal measured by the detector; the control unit is used to coordinate the work of the light source module, the spatial light modulator, and the single-pixel detector to ensure the synchronization and efficient operation of the system. The system of the present invention can achieve high-precision spatial positioning, with millimeter-level lateral resolution and centimeter-level longitudinal resolution.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical wireless communications, and in particular relates to a visible light communication and position sensing integrated system. Background Art

[0002] Visible Light Communication (VLC) is becoming one of the key technologies in the next-generation 6G network due to its high bandwidth and ultra-high-speed transmission capabilities. Typical application scenarios include indoor high-speed data transmission, smart homes, Internet of Vehicles, and the Internet of Things. For these application areas, there is an increasing demand for optical communication systems with integrated perception functions to achieve target-oriented beamforming and high-speed data services. However, existing integrated perception and communication systems usually rely on complex hardware configurations and signal processing algorithms, and are limited in accuracy and efficiency, making it difficult to achieve efficient perception and communication integration in practical applications.

[0003] In the field of visible light communication, the sensing or positioning technologies mainly include the following: 1. Optical fingerprint recognition: Use the spectral characteristics and spatial distribution of different light sources in the environment to create a unique optical fingerprint database. When the receiving device receives the light signal, spatial positioning can be achieved by comparing the optical fingerprint database. This method is affected by changes in the light environment in practical applications and requires frequent updates of the database. 2. Time difference ranging: Calculate the distance by measuring the propagation time of the light signal from the transmitter to the receiver. The measurement accuracy depends on the high-precision time synchronization mechanism and ranging algorithm. In an environment with severe multipath interference, the positioning accuracy will decrease. 3. Angle of arrival measurement: The spatial positioning of the device is achieved by analyzing the incident angle of the received light signal. This method is usually used in combination with multiple optical receivers to provide higher positioning accuracy, but requires a complex multi-receiver arrangement and precise angle measurement devices. 4. Optical phase shift measurement: Optical phase shift measurement uses the phase information of the light wave to calculate the distance and position of the object through the phase difference. This method has high accuracy, but is limited by the accuracy of the phase measurement device and ambient light interference.

[0004] In summary, there is currently a lack of a system and method that can efficiently integrate visible light communication and high-precision sensing technology, which can achieve both high-speed data transmission and high-precision spatial positioning. Summary of the invention

[0005] The present invention aims to solve the above problems and provide a visible light communication and position perception integrated system based on active illumination and computational reconstruction to improve data transmission rate and spatial positioning accuracy.

[0006] The present invention proposes a visible light communication and position sensing integrated system based on active illumination and computational reconstruction, which includes the following parts: a light source module, a spatial light modulator, a single-pixel photodetector, a communication signal processing unit, and a control unit: Figure 1 , Figure 2 As shown. Among them:

[0007] The light source module is used to generate illumination light for visible light communication signals; specifically, it includes a light source and a signal loading module; the light source adopts a high-bandwidth LED or white light laser light source, and is equipped with a signal generator to control the rapid change of the light source intensity to achieve high-speed time intensity modulation. The signal loading module is used to load the communication signal to be transmitted, and through digital signal processing technologies such as signal coding, bit & power loading, discrete multi-tone modulation, etc., the 0-1 digital signal is first encoded into a high-order signal, and then the signal to be transmitted is generated by the signal generator, and then the driving signal of the light source is obtained after passing through the amplifier and voltage bias module, and finally loaded into the illumination light source to drive the rapid intensity switching of the light source.

[0008] The spatial light modulator (SLM) is used to modulate the spatial distribution of the light field of the optical signal. The SLM dynamically modulates the light beam according to a preset modulation scheme to achieve synchronous high-resolution spatial positioning during data transmission.

[0009] The single-pixel photodetector is used to receive the light signal modulated by the spatial light modulator, convert it into an electrical signal, and measure the total intensity of the spatial light field; the single-pixel photodetector has high sensitivity and fast response capability.

[0010] The communication signal processing unit is used to recover the original communication signal and reconstruct the spatial position information from the timing signal measured by the single-pixel photodetector. The steps of communication signal processing correspond to the signal processing steps at the transmitting end, and mainly include signal demodulation, signal-to-noise ratio estimation, inverse mapping and other steps. The perception and reconstruction of spatial position information are performed independently from the recovery processing of the communication signal, and the algorithm for perception and reconstruction of spatial position information is related to the structured light illumination method. Compared with the method of obtaining spatial position based on cameras or multiple detection devices, the use of a single single-pixel detector can achieve a higher acquisition bandwidth, and spatial information perception and communication signal detection completely share the acquisition system, and perception can be achieved without additional equipment, which significantly reduces the complexity and cost of the detection end system.

[0011] The control unit is used to coordinate the work of the light source module, the spatial light modulator (SLM) and the single-pixel photodetector to ensure the synchronization and efficient operation of the system.

[0012] Based on the above integrated system, visible light communication and location awareness are integrated, including:

[0013] (1) Optical signal generation and modulation: The light source module generates a high-bandwidth LED or white light laser optical signal, and modulates the spatial distribution of the light field through a spatial light modulator (SLM) to generate a structured illumination pattern. These patterns interact with objects in the environment during propagation and carry the spatial information of the objects. At the same time, the light source module achieves data transmission through high-speed temporal intensity modulation. The high-speed intensity modulation of the signal and the spatial structured modulation mode are jointly optimized to ensure the simultaneous realization of high-performance communication and perception functions.

[0014] (2) Optical signal reception and conversion: The single-pixel detector receives the modulated optical signal and converts it into an electrical signal. Since the optical signal is modulated in time and space, the electrical signal contains the spatial information of the object and the data transmission information. The high sensitivity and fast response capability of the single-pixel detector ensure efficient signal reception.

[0015] (3) Signal demodulation and reconstruction: The communication signal processing unit demodulates and processes the received electrical signal, extracts the communication data, and uses a compressed sensing algorithm to reconstruct the spatial information. Through the dual processing of communication data demodulation and spatial information reconstruction, high-speed data transmission and high-precision spatial positioning can be achieved simultaneously.

[0016] (4) Synchronization and control: The control unit coordinates the work of the light source module, SLM, and single-pixel detector to ensure that the system maintains synchronization and efficient operation during data transmission and spatial perception. The control unit dynamically adjusts and optimizes the light source, SLM, and detector through a preset modulation scheme to ensure the stability and accuracy of the system.

[0017] The technical features and functional advantages of the present invention mainly include:

[0018] (1) High spatial positioning accuracy: The high-resolution spatial modulation capability of active illumination and the compressed sensing algorithm are used to achieve high-precision spatial positioning, providing millimeter-level lateral resolution and centimeter-level longitudinal resolution.

[0019] (2) Low system complexity: The integrated detection of communication data and spatial perception signals is achieved through a single single-pixel detector, which simplifies the system structure and reduces hardware cost and complexity. Compared with the traditional multi-device layout solution, the system design of the present invention is more compact and efficient.

[0020] (3) Efficient signal modulation: The design of the time-space modulation of the signal adopts a joint optimization strategy, which simultaneously ensures the high signal-to-noise ratio required for the optical communication function and the information required for the spatial perception function.

[0021] (4) Efficient signal processing: The data processing unit adopts advanced signal demodulation and compressed sensing algorithms to ensure the efficiency and accuracy of signal processing and meet the needs of high-speed and high-precision applications.

[0022] (5) Adaptive beamforming: The system has an adaptive beamforming function that can dynamically adjust the beam alignment direction and divergence angle based on the sensed position information, achieving high-speed data transmission within a wide coverage area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a framework diagram of the visible light communication and position sensing integrated system of the present invention.

[0024] Figure 2 It is a structural diagram of the visible light communication and position sensing integrated system of the present invention.

[0025] Figure 3 It is a diagram of the design and reconstruction algorithm of the spatial light coding pattern of compressive sampling in the communication signal processing unit of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below by way of embodiments in conjunction with the accompanying drawings.

[0027] The visible light communication and perception integrated system of the present invention includes a light source module, a spatial light modulator, a single-pixel photodetector, a communication signal processing unit, and a control unit, and also includes a signal light spatial transmission link; see Figure 2 As shown. Among them:

[0028] The light source may be a light emitting device of any wavelength and any power, and generally a light emitting diode (LED) or a laser diode (LD) with a relatively high modulation bandwidth is used to ensure a relatively high communication transmission rate.

[0029] The signal loading module is used to load the communication signal to be transmitted. Through digital signal processing technologies such as signal coding, bit & power loading, discrete multi-tone modulation, etc., the 0-1 digital signal is first encoded into a high-order signal, and then the signal to be transmitted is generated by the signal generator. After passing through the amplifier and voltage bias module, the driving signal of the light source is obtained, and finally loaded into the lighting light source to drive the rapid intensity switching of the light source.

[0030] The spatial light modulator uses a programmable spatial light modulator, such as a digital micro-mirror array device (DMD), which pre-loads a set of coding patterns and continuously modulates the light field at more than 20kHz. At this time, the speed of light change is much lower than the rate of the communication signal loaded at the transmitter. The time-space encoded light signal is transmitted through a distance of free space and then reaches the single-pixel photodetector as the detection end; the above time-space process can be expressed by the following formula:

[0031] R k (p,t)=T(t)S k (p) , (1)

[0032] Where T(t) is the target transmission signal, t represents time, S k (p) is the detection signal corresponding to the kth structured light pattern, and p represents the spatial position.

[0033] Single-pixel photodetector that measures the total intensity of a spatial light field.

[0034] In the communication signal processing unit, in order to achieve efficient spatial position information perception, the present invention proposes a compressed sampling spatial light coding pattern design and reconstruction algorithm. Figure 3 As shown in the figure. The spatial light coding pattern design uses two sets of one-dimensional Hadamard orthogonal basis patterns in different directions as the modulation pattern of the illumination light. This optimized illumination modulation scheme compresses the number of required coding patterns from the scale of N*N to the scale of 2*N, where N is the spatial resolution. The reconstruction algorithm first uses the inverse linear mapping algorithm to restore the horizontal and vertical target intensity projection information, denoted as P x and P y . Then use the geometric symmetry of the target and the scene sparsity prior to reconstruct the complete two-dimensional spatial distribution:

[0035]

[0036] From the reconstructed two-dimensional projection information P x and P y The three-dimensional relative position information of a single-pixel photodetector in the illumination domain can be estimated. Specifically, the present invention approximates the theoretical model of the projection information by function fitting. Since the theoretical model is a discontinuous zero-valued truncated second-order function, the present invention designs the following approximate function:

[0037]

[0038] Here, x, y and R are the horizontal and vertical spatial positions, respectively, and the relative size of the aperture size of the single-pixel photodetector to the field of view space, x0 and y0 are the positions of the detector center in the illuminated area, and k is a parameter determined by experimental tests, usually k is taken as 10. The distance D of a single-pixel photodetector is proportional to the relative aperture, which can be based on the pre-calibrated distance D ref and caliber R ref The calculation results are:

[0039] D=D ref *R ref / R, (6).

[0040] The overall signal optical space transmission link is as follows Figure 2 As shown. In the transmitter signal processing part, the bit power loading discrete multi-tone (DMT) modulation based on the Levin-Campello (LC) algorithm is used to maximize the spectral efficiency of the visible light communication channel. First, a quadrature phase shift keying (QPSK) signal containing 256 subcarriers and their conjugate symmetry is generated to estimate the signal-to-noise ratio (SNR) of each subcarrier. In the test phase, the transmitted signal is first bit power loaded, then converted into a complex value signal through orthogonal amplitude modulation mapping (QAM), and finally DMT modulated.

[0041] The modulated signal is loaded onto the signal generator to generate a control signal, which is then passed through the voltage amplification and offset module and finally loaded onto the light source to drive its brightness change. The emitted light passes through a lens to shrink the beam divergence angle and is then projected onto the spatial light modulator for spatial encoding, and then projected to the far end through another lens.

[0042] After receiving the optical signal, the detector performs signal processing, which includes the following steps: The received signal first passes through the standard DMT demodulation process to extract the signal of each subcarrier. Then, the LC algorithm is used to calculate the optimal bit and power allocation for each subcarrier, and the SNR of each subcarrier is determined based on the error vector amplitude of the constellation point. Subsequently, QAM demapping is performed to restore the final communication signal.

[0043] Figure 3 It is a diagram of the design and reconstruction algorithm of the spatial light coding pattern of compressed sampling in the communication signal processing unit. Among them, (a) is a schematic diagram of a certain position in the three-dimensional space covered by the structured light illumination of the detection end at the transmitting end. (b) is a partial pattern of the spatial light coding pattern design in the form of a one-dimensional Hadamard matrix in a set of orthogonal directions. (c) is the detection signal obtained by the structured light design corresponding to Figure (b), and (d) is the spatial information restored by image reconstruction based on the measurement value of (c).

[0044] The active spatial illumination method proposed in the present invention is highly robust to the interference of ambient light, and can achieve spatial position detection with higher spatial resolution by setting a finer stripe pattern, which is particularly suitable for position estimation with millimeter-level resolution accuracy in a smaller space. The compressed sampling and reconstruction method proposed in the present invention can achieve efficient collection of spatial information, achieve real-time spatial position reconstruction, and support beamforming in actual optical communication systems.

Claims

1. A visible light communication and position sensing integrated system based on active illumination and computational reconstruction, characterized in that: It includes a light source module, a spatial light modulator, a single-pixel photodetector, a communication signal processing unit, and a control unit: wherein: The light source module is used to generate illumination light for visible light communication signals; specifically, it includes a light source and a signal loading module; the light source adopts a high-bandwidth LED or white light laser light source, and is equipped with a signal generator to control the rapid change of the light source intensity to achieve high-speed time intensity modulation; the signal loading module is used to load the communication signal to be transmitted, and through signal encoding, bit & power loading, discrete multi-tone modulation digital signal processing technology, the 0-1 digital signal is first encoded into a high-order signal, and then the signal to be transmitted is generated by the signal generator, and then the driving signal of the light source is obtained after the amplifier and voltage bias, and finally loaded into the illumination light source to drive the rapid intensity switching of the light source; The spatial light modulator is used to modulate the spatial distribution of the light field of the optical signal; specifically, the spatial light modulator dynamically modulates the light beam according to a preset modulation scheme to achieve synchronous high-resolution spatial positioning during data transmission; The single-pixel photodetector is used to receive the light signal modulated by the spatial light modulator, convert it into an electrical signal, and measure the total intensity of the spatial light field; the single-pixel photodetector has high sensitivity and fast response capability; The communication signal processing unit is used to recover the original communication signal and reconstruct the spatial position information from the time series signal measured by the single-pixel photodetector; the steps of communication signal processing correspond to the signal processing link of the transmitting end, including signal demodulation, signal-to-noise ratio estimation, and inverse mapping; the perception reconstruction of the spatial position information and the recovery processing of the communication signal are performed independently; The control unit is used to coordinate the work of the light source module, the spatial light modulator and the single pixel detector to ensure the synchronization and efficient operation of the system; In the communication signal processing unit, a compressed sampling spatial light coding pattern design scheme and a reconstruction algorithm are adopted; the spatial light coding pattern design scheme adopts two sets of one-dimensional Hadamard orthogonal basis patterns in different directions as the modulation pattern of the illumination light, and compresses the required number of coding patterns from the scale of N*N to the scale of 2*N, where N is the spatial resolution; the reconstruction algorithm first uses an inverse linear mapping algorithm to restore the horizontal and vertical target intensity projection information, denoted as P x and P y ; Then use the geometric symmetry of the target and the scene sparsity prior to reconstruct the complete two-dimensional spatial distribution: From the reconstructed two-dimensional projection information P x and P y The three-dimensional relative position information of the single-pixel photodetector in the illumination domain is estimated. Specifically, the theoretical model of the projection information is approximated by function fitting; the theoretical model is a discontinuous zero-valued truncated second-order function, and the following approximate function is designed: Here, x, y and R are the horizontal and vertical spatial positions, respectively, and the relative size of the aperture size of the single-pixel photodetector to the field of view space; x0 and y0 are the positions of the detector center in the illuminated area, and k is a parameter determined by experimental testing; the distance D of the single-pixel photodetector is proportional to the relative aperture, based on the pre-calibrated distance D ref and caliber R ref The calculation results are: D=D ref *R ref / R, (6)。 2. The visible light communication and location sensing integrated system according to claim 1, characterized in that: The spatial light modulator uses a programmable digital micromirror array device (DMD), which preloads a set of coding patterns and continuously modulates the light field at more than 20kHz. At this time, the speed of light change is much lower than the rate of the communication signal loaded at the transmitting end; the time-space encoded light signal is transmitted through a distance of free space to reach the single-pixel photodetector as the detection end; the above time-space encoding process is expressed by the following formula: R k (p,t)=T(t)S k (p) , (1) Where T(t) is the target transmission signal, t represents time, S k (p) is the detection signal corresponding to the kth structured light pattern, and p represents the spatial position.

3. A visible light communication and location awareness integration method based on the visible light communication and location awareness integration system according to claim 1, characterized in that: Specifically include: (1) Optical signal generation and modulation: The high-bandwidth LED or white-light laser optical signal generated by the light source module is modulated by a spatial light modulator to generate a structured illumination pattern. These patterns interact with objects in the environment during propagation and carry the spatial information of the objects. At the same time, the light source module transmits data through high-speed temporal intensity modulation. The high-speed intensity modulation and spatial structured modulation modes of the signal are jointly optimized to ensure high-performance communication and perception functions. (2) Optical signal reception and conversion: A single-pixel photodetector receives the modulated optical signal and converts it into an electrical signal. Since the optical signal is modulated in time and space, the electrical signal contains the spatial information of the object and the data transmission information. The high sensitivity and fast response capability of the single-pixel photodetector ensure efficient signal reception. (3) Signal demodulation and reconstruction: The communication signal processing unit demodulates and processes the received electrical signal, extracts the communication data, and uses a compressed sensing algorithm to reconstruct the spatial information. Through the dual processing of communication data demodulation and spatial information reconstruction, high-speed data transmission and high-precision spatial positioning are achieved simultaneously. (4) Synchronization and control: The control unit coordinates the operation of the light source module, spatial light modulator, and single-pixel photodetector to ensure that the system maintains synchronization and efficient operation during data transmission and spatial perception. The control unit uses a preset modulation scheme to dynamically adjust and optimize the light source, spatial light modulator, and single-pixel photodetector to ensure the stability and accuracy of the system.

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