VLCP system based on multiple LEDs, RIS parameter configuration and power distribution method and related equipment

Abstract

The invention provides a VLCP system based on multiple LEDs, an RIS parameter configuration and power distribution method and related equipment, and relates to the technical field of visible light communication. The system comprises a transmitter, a receiver and an intelligent metasurface RIS. The transmitter comprises a controller and NL non-collinear LEDs, and NL is greater than or equal to 3; each LED is used for transmitting an optical signal, so that a transmitter modulates a positioning signal and a communication signal based on the optical signal; the controller is used for controlling the RIS to be in a working state in a communication process; when the line-of-sight link is not shielded, the RIS is controlled to be in a closed state in the positioning process; when the line-of-sight link is shielded, controlling the RIS to provide a non-line-of-sight link capable of transmitting a positioning signal to a receiver; the receiver is used for positioning the position information of the receiver according to the positioning signal and transmitting the position information to the transmitter; and the transmitter is used for estimating channel state information according to the position information of the receiver and transmitting the communication signal to the receiver according to the estimated channel state information.

Description

Technical Field

[0001] The present invention relates to the field of visible light communication technology, and in particular to a VLCP system based on multiple LEDs, a RIS parameter configuration and power allocation method, and related equipment. Background Art

[0002] In recent years, visible light communication (VLC) has attracted extensive attention from relevant researchers as an indoor wireless communication technology. In addition to alleviating the spectrum pressure of radio frequency communication, VLC also has the advantages of low power consumption, high energy efficiency, no radio frequency interference, and high confidentiality, and is expected to promote the realization of the Internet of Everything and intelligent twin vision in 6G. Visible light positioning (VLP) technology is a technology that uses VLC for indoor positioning. VLP technology can be implemented through several classic positioning algorithms. The optical signal is detected and analyzed by a photodetector (PD), and the positioning information is obtained according to the corresponding positioning algorithm based on optical properties. The widely used positioning algorithms in VLP include time of arrival (TOA), time difference of arrival (TDOA), phase of arrival (POA), phase difference of arrival (PDOA), angle of arrival (AOA), and received signal strength (RSS). However, compared with other algorithms that require extremely precise synchronization, the RSS positioning algorithm is the most common due to its lower complexity and cost. Unlike radio frequency positioning technology, with the characteristics of low multipath effect and low measurement cost, the VLP system can achieve high-precision positioning estimation based on RSS. The high positioning accuracy provided by VLP ensures real-time communication, which is conducive to human-computer interaction and the Internet of Everything in the future 6G ubiquitous network.

[0003] In order to tap the advantages of the above two technologies, the visible light communication and positioning integrated (VLCP) system has attracted the attention of researchers in recent years. VLCP is a new technology that combines the advantages of VLC and VLP and is expected to be widely used in future indoor home networks. In the current VLCP system, data transmission is usually based on the line-of-sight (LoS) positioning signal, and the channel state information (CSI) estimation is obtained through the VLP positioning result, and then data transmission is performed. The structure is as follows Figure 1 As shown in the figure, this scheme proposes a robust power allocation scheme for integrated VLCP network by exploiting the intrinsic connection between positioning and communication, and derives the explicit relationship between random positioning error and CSI error following Gaussian distribution and arbitrary distribution; then, the CRLB of positioning error is minimized under rate interruption constraint and power constraint. However, in daily life, there is often line-of-sight occlusion, and visible light is very sensitive to line-of-sight (LoS) transmission, but the system does not consider the working condition of VLCP system under the condition of line-of-sight occlusion. Summary of the invention

[0004] Aiming at the problem that the existing VLCP system is sensitive to LoS ​​transmission and cannot work well when there is line-of-sight obstruction, the present invention proposes a VLCP system based on multiple LEDs, RIS parameter configuration and power allocation method and related equipment.

[0005] In a first aspect, the present invention provides a VLCP system based on multiple LEDs, including a transmitter and a receiver, and also including: an intelligent metasurface RIS; the transmitter includes a controller and an N L LEDs that are not collinear, N L ≥3;

[0006] Each of the LEDs is used to emit a light signal, so that the transmitter can modulate the positioning signal and the communication signal based on the light signal;

[0007] The controller is used to control the RIS to be in a working state during the communication process; when the line-of-sight link is not blocked, control the RIS to be in a closed state during the positioning process; when the line-of-sight link is blocked, control the RIS to provide a non-line-of-sight link capable of transmitting a positioning signal to the receiver;

[0008] The receiver is used to locate the position information of the receiver according to the positioning signal and transmit the position information to the transmitter;

[0009] The transmitter is used to estimate channel state information according to the position information of the receiver, and transmit the communication signal to the receiver according to the estimated channel state information.

[0010] In a second aspect, the present invention provides a RIS parameter configuration and power allocation method for a VLCP system based on multiple LEDs, comprising:

[0011] Modeling a matching relationship among the LED, the RIS unit, and the receiver, and determining a first constraint condition according to the matching relationship;

[0012] Determine the constraint conditions that the transmitted signal in the VLCP system needs to meet, recorded as the second constraint condition;

[0013] Under the matching relationship, determine the achievable data rate constraint condition that the VLCP system needs to meet, which is recorded as the third constraint condition; the achievable data rate is jointly determined by the communication power allocation coefficient and the positioning power allocation coefficient of the LED;

[0014] The Cramer-Rao lower bound is used as the positioning performance evaluation index of the VLCP system, so that the RIS parameter configuration and power allocation problem is converted into a problem of optimizing the positioning performance evaluation index under the common constraints of the first constraint condition, the second constraint condition and the third constraint condition, and the minimum value of the positioning performance evaluation index is obtained. The matching relationship, communication power allocation coefficient and positioning power allocation coefficient corresponding to the minimum value of the positioning performance evaluation index are the optimal RIS parameter configuration and power allocation strategy.

[0015] Further, finding the minimum value of the positioning performance evaluation index specifically includes:

[0016] The problem of optimizing the positioning performance evaluation index under the common constraints of the first constraint condition, the second constraint condition and the third constraint condition is split into a first optimization sub-problem and a second optimization sub-problem, so as to obtain the optimal value of the positioning performance evaluation index by adopting an alternating optimization algorithm;

[0017] Among them, the first optimization sub-problem is: under the first constraint condition, given the matching relationship between the LED, RIS unit and the receiver, solve the optimal communication power allocation coefficient and positioning power allocation coefficient that meet the second constraint condition and the third constraint condition; the second optimization sub-problem is: under the second constraint condition and the third constraint condition, given the communication power allocation coefficient and the positioning power allocation coefficient, solve the optimal matching relationship between the LED, RIS unit and the receiver that meets the first constraint condition.

[0018] Furthermore, when solving the first optimization sub-problem, the matching relationship between the LED, RIS unit and receiver is initialized based on the minimum distance criterion; the distance refers to the distance of the LED transmission signal from the LED to the RIS unit and then from the RIS unit to the receiver.

[0019] Furthermore, the second constraint condition includes a non-negativity condition of the transmitted signal, a peak power constraint condition of the transmitted signal, and an average power constraint condition of the transmitted signal.

[0020] Furthermore, the third constraint condition is that the interruption probability of the communication signal should not be greater than the maximum tolerable interruption probability; wherein the interruption probability refers to the probability that the achievable data rate is not greater than the quality of service constraint.

[0021] Furthermore, when solving the first optimization subproblem, the optimal communication power allocation coefficient and positioning power allocation coefficient are derived using a conditional risk value-based method and a continuous convex approximation method.

[0022] Furthermore, when solving the second optimization sub-problem, the maximum received power selection principle is used to derive the optimal matching relationship between the LED, the RIS unit and the receiver.

[0023] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in the second aspect when executing the program.

[0024] In a fourth aspect, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method described in the second aspect.

[0025] The beneficial effects of the present invention are:

[0026] (1) The multi-LED based VLCP system provided by the present invention is a RIS-assisted positioning-centric multi-LED VLCP system model. The present invention utilizes an intelligent metasurface (RIS) and adds it to the VLCP communication system to realize the functions of VLC and VLP from an endogenous mechanism, and reduce the sensitivity to the visible light LoS link, thereby achieving the purpose of simultaneously improving the communication and positioning performance.

[0027] (2) The RIS parameters and power allocation method in the RIS-assisted multi-LED VLCP system provided by the present invention adopts the Cramer-Rao next door (CRLB) and the interruption probability as the measurement of positioning performance and communication performance respectively, and systematically models the RIS-assisted VLCP system under the conditions of the presence and absence of LoS. By changing the RIS parameters, the channel gain can be changed, thereby improving the communication and positioning performance of the entire system.

[0028] (3) Under the constraints of transmission signal, positioning performance index and communication performance index, an optimization problem is established with CRLB as the optimization target, positioning power allocation, communication power allocation and RIS parameters as optimization variables. For this non-convex optimization problem, an alternating optimization (AO) algorithm is proposed to solve it, which has strong convergence and high stability.

[0029] (4) The worst-case distribution of the Conditional Value at Risk (CVaR) and the Successive Convex Approximation (SCA) technique are used to derive a feasible solution to the power coefficient optimization subproblem, and the Maximum Received Power Combining (MRPC) principle is proposed to optimize the RIS allocation matrix. The effectiveness of RIS in the integrated VLCP system is verified through simulation experiments, especially when the LoS link is blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a VLCP system under multiple LEDs in the prior art;

[0031] Figure 2 A VLCP system model diagram based on multiple LEDs provided in an embodiment of the present invention;

[0032] Figure 3 A diagram of the working process of the VLCP system provided by an embodiment of the present invention;

[0033] Figure 4 A schematic flow chart of a RIS parameter configuration and power allocation method for a VLCP system based on multiple LEDs provided by an embodiment of the present invention;

[0034] Figure 5 A top view of a RIS-assisted VLCP system provided by an embodiment of the present invention;

[0035] Figure 6 A relationship diagram between CRLB and noise power of a RIS-assisted four-LED VLCP system provided in an embodiment of the present invention;

[0036] Figure 7 A relationship diagram between CRLB and noise power of a RIS-assisted three-LED VLCP system provided in an embodiment of the present invention;

[0037] Figure 8 A relationship diagram between CRLB and rate threshold under given interruption probability and noise power provided by an embodiment of the present invention;

[0038] Figure 9 A CDF of a data rate that can be achieved under a given interruption probability and rate threshold provided by an embodiment of the present invention;

[0039] Figure 10 A structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Since the existing methods do not consider the working conditions of the VLCP system under the condition of line-of-sight obstruction, and in practical applications, visible light is highly sensitive to line-of-sight, it is necessary to provide a working solution under line-of-sight obstruction. The present invention considers that RIS is an emerging technology for configurable wireless environment, and the use of RIS has a huge improvement in the performance gain of communication. Therefore, the present invention considers combining RIS with the VLCP system to achieve the robustness of communication and positioning capabilities in indoor visible light networks.

[0042] The present invention is mainly based on a visible light communication and positioning integrated (VLCP) system that can realize communication and positioning functions at the same time, aims to reduce the sensitivity of visible light line-of-sight occlusion, and proposes to use an intelligent metasurface (Reconfigurable Intelligent Surface, RIS) to provide an auxiliary VLCP system for communication positioning. In addition, by designing the RIS parameter configuration and transmitter power allocation scheme, the RIS parameter configuration and the power allocated for positioning and communication are jointly optimized under the premise of meeting the achievable data rate, RIS parameter restrictions and total transmission power constraints, so as to minimize the positioning indicator Cramer-Rao lower bound.

[0043] The embodiment of the present invention provides a multi-LED VLCP system, including a transmitter and a receiver, and also includes: an intelligent metasurface RIS; the transmitter includes a controller and an N L LEDs that are not collinear, N L ≥3;

[0044] Each of the LEDs is used to emit an optical signal for the transmitter to modulate the positioning signal and the communication signal based on the optical signal. The controller is used to control the RIS to be in a working state during the communication process; when the line-of-sight link is not blocked, the RIS is controlled to be in a closed state during the positioning process; when the line-of-sight (LoS) link is blocked, the RIS is controlled to provide a non-line-of-sight link (NLoS) capable of transmitting the positioning signal to the receiver. The receiver is used to locate the position information of the receiver according to the positioning signal, and transmit the position information to the transmitter. The transmitter is used to estimate the channel state information according to the position information of the receiver, and transmit the communication signal to the receiver according to the estimated channel state information.

[0045] Based on the above embodiments,Figure 2 As shown, a channel model of a RIS-assisted integrated VLCP system is given. Figure 2 Figure 2 shows the optical VLCP system model when there are LoS links. L Non-collinear LEDs to ensure the transmitter's ability to locate the receiver's 3D position (N L ≥3). In this case, the RIS controller encapsulated in the transmitter controls the RIS to be activated during the communication process and deactivated during the positioning process. In addition, when the LoS link is blocked by other users or non-users, the receiver can only locate itself through the RIS retransmission signal. At this time, RIS plays an important role in the positioning process. Accordingly, the transmitter estimates the channel state information CSI based on the positioning result and implements the communication process based on the estimated CSI.

[0046] In an exemplary embodiment, Figure 3 As shown, in order to prevent interference between the positioning signal and the communication signal, the two transmission signals are transmitted using different frequencies.

[0047] In an exemplary embodiment, Figure 3 As shown, in order to determine the source of the positioning signal, different transmission frequencies can be used for the positioning signals emitted by different LEDs; it is understandable that the code division multiple access method can also be used to distinguish the source of the positioning signal.

[0048] In an exemplary embodiment, the receiver processes the positioning signal based on the RSS scheme to estimate the receiver position, and transmits the positioning information to the transmitter through an uplink based on infrared communication (IR); the transmitter estimates the channel state information CSI based on the feedback information of the receiver, and transmits the communication signal through a downlink through visible light; Figure 3 shown.

[0049] It can be understood that the above VLCP system can be used to achieve LoS positioning or NLoS positioning. The former is based on the existence of the LoS link and the RIS is offline; the latter is due to the obstruction of the LoS, and the RIS is used to provide an additional NLoS link to transmit positioning information. The receiver receives the positioning signal during the positioning process and estimates the RSS information based on the received positioning signal.

[0050] Since the channel gain is a function of the receiver position, the receiver position information can be derived from the channel gain. Based on this principle, the signal model and channel model of the VLCP system are given below.

[0051] For the i-th LED, at the transmission frequency f p,i Up-modulate the positioning signal at the transmission frequency f cTherefore, assuming that the communication signal and positioning signal of the i-th LED are respectively expressed by s p (t) and s c (t) indicates that the LED communication and positioning integrated signal model can be expressed as

[0052]

[0053] where p p,i and p c,i represents the positioning power allocation coefficient and the communication power allocation coefficient, I DC It represents the DC deviation caused by the direct detection of brightness modulation (IM / DD) in visible light transmission. represents the set of LEDs. Without loss of generality, it is assumed that the positioning signal and the communication signal satisfy the corresponding constraints |s p (t)|≤A, |s c (t)|≤A, Where A represents the electrical signal constraint and A>0.

[0054] The DC component can be processed by a direct isolation circuit, so the positioning signal received from the i-th LED is expressed as

[0055]

[0056] where n p,i (t) represents additive white Gaussian noise (AWGN).

[0057] Since the communication signals of different LEDs are transmitted at the same frequency, the communication signal received by the receiving end can be characterized as

[0058]

[0059] In the formula is the channel matrix of the multi-LED VLCP system, x c (t) is the communication signal vector from the LED, and x c (t) = w c s c (t). c is the communication power allocation coefficient vector of different LEDs, and n c (t) is additive white Gaussian noise (AWGN), and Among them B c is the bandwidth of the communication signal.

[0060] Therefore, considering the constraints on the transmitted signal in the VLCP system, the transmitted signal should meet the following constraints:

[0061]

[0062] The first constraint ensures the non-negativity of the transmitted signal in the VLCP system, the second constraint represents the peak power constraint, and the third constraint represents the average power constraint, which correspond to the safety requirements of human eyes and the limitations of actual circuits respectively. o Indicates the maximum light power of each LED lamp, P e Indicates the maximum electrical power of each LED lamp.

[0063] In order to simulate the real scene, the channel model of the VLCP system proposed in this paper takes into account the LoS occlusion problem, including user self-occlusion and non-user occlusion. Therefore, the channel gain between the i-th LED and the receiver can be expressed as

[0064]

[0065] in represents the indicator function for determining whether the i-th LoS link is blocked, Represents the indicator function that determines when RIS is online. and They represent the i-th LoS and NLoS channel gains respectively. Since the weak reflection effect caused by the regular wall can be ignored, in the present invention, the NLoS channel gain only considers the component caused by RIS.

[0066] It is understandable that It is used to assist the communication process and avoid deteriorating the positioning process. This is because the improvement of positioning performance by RIS depends on the position of the receiver, so the application of RIS does not necessarily improve positioning performance. In order to avoid the negative impact of RIS in the positioning process, in the VLCP system, if a LoS link exists, RIS is set offline during the positioning process. When a LoS link exists, the positioning process is implemented based on the RSS information obtained from the LoS transmission, and the communication process is implemented through the LoS and RIS reflection links. At the same time, when the LoS link is blocked (if the receiving end cannot receive the signal of this frequency, the LoS link from the LED is judged to be blocked), RIS is used to provide additional NLoS positioning signals and implement corresponding auxiliary communications.

[0067] Based on the above, we know that the two indicator functions and There is a logical relationship between them, which can be represented as

[0068]

[0069] in and ∨ represent logical XOR and logical AND operations respectively. This formula avoids the negative impact of RIS on the positioning process when the LoS link exists. When the LoS link is blocked, RIS can provide additional NLoS positioning signals. During the communication process, it ensures that there is still a communication link even when the LoS link is blocked. Therefore, the indicator function Can be Sure.

[0070] In an exemplary embodiment, the indicator function may be Defined as

[0071]

[0072] in Indicates user self-occlusion, represents the mutual interference from the mth non-user, represents no occlusion, M represents the number of non-user occlusions, and ∏ represents the product operation.

[0073] In an exemplary embodiment, the i-th LoS channel gain can be expressed as

[0074]

[0075] Where m', A re and d i,u represents the Lambert index, the area of ​​the photodetector (PD), and the distance between the i-th LED and the receiver. m' and the LED half-illuminance half-angle θ 1 / 2 It can be related to m' = -1 / log 2 (cos(Θ 1 / 2 )) to characterize. and are the irradiance angle and incident angle of the i-th LED respectively. oc (·) and T of (·) represent the optical focusing gain and optical filtering gain respectively. of (·) is usually set to a constant, while the optical focusing gain T oc (·) is related to the refractive index and field of view (FoV) of the PD. The relationship can be expressed as

[0076]

[0077] Where α is the refractive index, Ψ FoV is the FoV. Therefore, the LoS channel vector can be expressed as

[0078] In an exemplary embodiment, regarding the i-th NLoS channel gain, the NLoS channel model constructed by RIS can be described by introducing a distribution matrix. The optical RIS reflection channel can be modeled as a spherical wave model, which is more likely to follow the near-field propagation of the "additive" model rather than the far-field propagation of the "multiplicative" form. At the same time, considering the nanometer wavelength and transmission characteristics of the light wave, the optical RIS reflection channel can be approximately regarded as the following geometric optics. The power density of the reflected signal is mainly concentrated in the direction that follows the reflection law, and the energy leakage in any deviation direction can be ignored. Therefore, this embodiment can define a distribution matrix to determine the matching relationship between the LED, RIS unit and receiver.

[0079] Specifically, given an allocation matrix N r is the number of optical RIS units, g n,i = 1 means that the transmission signal of the i-th LED is reflected by the n-th RIS unit. At the same time, due to the narrow beam width, one RIS unit can only be assigned to one LED, which results in the following constraints:

[0080]

[0081] in Represents a collection of RIS units.

[0082] Based on the additive model, the reflection channel gain of the i-th LED sent to the receiver through the n-th RIS unit can be expressed as

[0083]

[0084] Where δ represents the reflection coefficient of the RIS unit, which is assumed to be a constant in the present invention, and are the distances from the i-th LED to the n-th RIS unit and from the n-th RIS unit to the receiver, respectively. and are the irradiance angle and incident angle of the path from the i-th LED to the n-th RIS unit to the receiver, respectively. oc (·) and T of (·) can refer to the LoS gain. Therefore, the NLoS channel gain of the i-th LED can be expressed as

[0085]

[0086] in Considering the non-line-of-sight channel matrix make The non-line-of-sight channel vector can be expressed as

[0087]

[0088] Therefore, let The channel matrix of the multi-LED VLCP system can be expressed as

[0089]

[0090] At this point, the channel model has been established.

[0091] Based on the above channel model, LoS positioning and NLoS positioning (also called RIS positioning) are further introduced below.

[0092] In an exemplary embodiment, LoS positioning obtains positioning information based on LoS transmission in VLP. In this case, RIS is offline, the NLoS channel gain is zero, and according to the Lambert formula, the position information can be estimated according to equations (2) and (8).

[0093] According to formula (2), the electrical power of the i-th received positioning signal can be expressed as

[0094]

[0095] Since the channel gain is a function of the receiver position, the receiver position information can be derived according to equation (8). The LoS channel gain can be restated as

[0096]

[0097] in l i and u are the positions of the i-th LED and receiver respectively, n i and n u are the directions of the i-th LED and receiver respectively.

[0098] For example, suppose the LED is pointing downward and the receiver is pointing upward (i.e. n i =(0,0,-1) and n u =(0,0,1)), then the channel gain can be expressed as

[0099]

[0100] in and z u is the z-axis coordinate of the ith LED and the receiver. Combining equations (16) and (17), the position of the receiver can be estimated based on the received positioning signal and the position of the LED. The estimated position information can be used for channel estimation in the next cycle.

[0101] In an exemplary embodiment, when the LoS path is blocked, RIS can provide an additional NLoS link and transmit the positioning signal of the LED, thereby avoiding the interruption of the positioning process. In RIS positioning, assuming that the LoS link of the i-th LED is blocked, RIS provides an additional NLoS link Similarly, the positioning information of the receiving end can be estimated based on the relationship between the channel gain and the received positioning signal.

[0102] In this case, the received power characteristic of the i-th positioning signal is

[0103]

[0104] Since the channel gain is a function of the receiver position, the channel gain can be derived from the received positioning signal and the position can be solved. The derivation process is as follows: First, the reflection channel gain guided from the i-th LED to the receiver through the n-th RIS unit in equation (11) can be rewritten as

[0105]

[0106] in is the position of the nth RIS unit.

[0107] For example, assuming the LED is oriented downward and the receiver is oriented upward, the above formula can be re-expressed as

[0108]

[0109] in is the z-axis coordinate of the nth RIS unit. Since the positions of the LED and RIS units are known, when the LoS path is blocked, the position information of the receiver can be estimated based on the received RIS reflected positioning signal. When the allocation matrix is ​​determined, the position of the receiver is estimated based on the i-th NLoS positioning signal, combining equations (12), (18) and (20).

[0110] Combining the above equations, the receiver's position can be estimated from the power of the signal received by the receiver. This relationship can be expressed as

[0111]

[0112] Furthermore, the positioning error can also be calculated. In an exemplary embodiment, assuming that the positioning error follows a Gaussian distribution, the error can be expressed as

[0113]

[0114] in is the estimated position of the receiver, e u =[e x ,e y ,e z ] is the positioning error that obeys Gaussian distribution, with a mean of 0 and a covariance matrix of R p The variance of the positions should satisfy the constraints of CRLB, which will be derived in the next section.

[0115] Furthermore, in the uplink transmission phase, the positioning information of the receiver is transmitted to the transmitter so that the transmitter can obtain channel state information based on the estimated receiver position. However, due to the existence of positioning errors, the CSI is not perfect. represents the estimated CSI, and the CSI error can be expressed as Specifically, the i-th estimated channel gain can be expressed as

[0116]

[0117] At the same time, the CSI error of the i-th channel can be expressed as

[0118]

[0119] in From the equation, we can see that the CSI error is a function of the position error.

[0120] According to formula (24), if we define Then the probability density function of the CSI error of the i-th channel can be expressed as

[0121]

[0122] in, It is the inverse function of formula (24). Therefore, the communication performance index can be calculated according to the probability density function of CSI error and the data transmission process can be affected accordingly.

[0123] From the above, it can be seen that when the position of the receiver is completely unknown (this is uncommon, because even if the i-th LoS path is blocked, there are other LoS paths that can achieve positioning, but this possibility exists), the allocation matrix used to characterize the matching relationship between LEDs, RIS units and receivers is randomly selected to obtain the approximate position of the receiver. However, when the positioning information is partially known, the allocation matrix can be optimized to improve the positioning accuracy. At the same time, in the VLCP system, due to the limited total power of the LED, the power allocation of the system needs to be reasonably designed to obtain better system performance. Therefore, the embodiment of the present invention further provides a RIS parameter configuration and power allocation method for a VLCP system based on multiple LEDs, such as Figure 4 As shown, the following steps are included:

[0124] S401: Modeling a matching relationship between an LED, a RIS unit and a receiver, and determining a first constraint condition according to the matching relationship;

[0125] In an exemplary embodiment, the allocation matrix Modeling the matching relationship between the LED, RIS unit and receiver. The first constraint condition generated based on the matching relationship is shown in formula (10).

[0126] S402: Determine a constraint condition that a transmitted signal in the VLCP system needs to satisfy, recorded as a second constraint condition;

[0127] In an exemplary embodiment, based on the signal model given above, it can be determined that the constraint condition that the transmitted signal needs to satisfy is as shown in formula (4).

[0128] S403: Under the matching relationship, determine a achievable data rate constraint condition that the VLCP system needs to satisfy, recorded as a third constraint condition; the achievable data rate is jointly determined by the communication power allocation coefficient and the positioning power allocation coefficient of the LED;

[0129] Specifically, the achievable data rate is selected to represent the communication performance. In the communication stage, the user can select a suitable modulation method according to the needs to modulate the light signal emitted by the LED to generate a communication signal.

[0130] In an exemplary embodiment, pulse amplitude modulation (PAM) is selected as the modulation method in the communication process because PAM has the advantages of high spectrum efficiency and strong practicality. Correspondingly, the communication performance is expressed by considering the achievable data rate under the PAM modulation method, which can be expressed as

[0131]

[0132] Where q is the ratio of transmitted optical power to electrical energy, and κ is the PD response coefficient, which is usually set to a constant. Therefore, the achievable data rate is the communication power allocation coefficient vector w c , estimated channel gain and CSI error e h It is understandable that the user may also select other modulation modes, and the present invention does not limit the modulation mode.

[0133] It can be understood that the estimated channel gain is obtained based on the estimated position of the receiver, which is obtained by the received positioning signal. At the same time, the received positioning signal can be determined based on the positioning power and the RIS allocation matrix. Therefore, the estimated channel gain is a function of the positioning signal power and the RIS allocation matrix (i.e., the RIS allocation matrix). The positioning power allocation coefficient vector and the RIS allocation matrix G. The CSI error is also determined by the estimated error of the receiver position. Assume that the position error satisfies the Gaussian distribution (i.e. ), the covariance matrix satisfies the CRLB constraint, which is related to the positioning power and RIS allocation matrix, which will be introduced below. Therefore, the achievable data rate is also affected by the positioning power allocation coefficient w p and the communication power allocation coefficient w c impact.

[0134] S404: The Cramer-Rao lower bound is used as the positioning performance evaluation index of the VLCP system, so as to convert the RIS parameter configuration and power allocation problem into a problem of optimizing the positioning performance evaluation index under the common constraints of the first constraint condition, the second constraint condition and the third constraint condition, and find the minimum value of the positioning performance evaluation index. The matching relationship, communication power allocation coefficient and positioning power allocation coefficient corresponding to the minimum value of the positioning performance evaluation index are the optimal RIS parameter configuration and power allocation strategy.

[0135] Specifically, the Cramer-Rao lower bound of this embodiment can be obtained by the following derivation process: It can be observed that the variance of the position error should satisfy

[0136]

[0137] Among them J u (w p ,G) is the Fisher information matrix (FIM), which can be calculated by the log-likelihood function of the received signal. The derivation process is as follows.

[0138] The likelihood function of the positioning signal received from the i-th LED is expressed as

[0139]

[0140] Therefore, the likelihood function can be expressed as

[0141]

[0142] Where ι represents a parameter that is independent of u. Estimated receiver position Characterized by

[0143]

[0144] The FIM of the estimated position can be defined as

[0145]

[0146] where k,l∈{1,2,3} and u krepresents the coordinate of the receiver in the k-th coordinate axis. FIM can be further expressed as

[0147]

[0148] where x u and u Represent the x-axis and y-axis coordinates of the receiver respectively. The first-order partial derivative of the log-likelihood function can be expressed as

[0149]

[0150] where k∈{1,2,3}. Then, the second-order partial derivative of the log-likelihood function can be expressed as

[0151]

[0152] Due to the constraints of the positioning signal, we can know and Therefore, the terms in FIM can be expressed as

[0153]

[0154] According to formula (5), we can know

[0155]

[0156] According to equations (17) and (20), we can observe that

[0157]

[0158] According to formula (12), we can observe

[0159]

[0160] in Considering the non-line-of-sight channel matrix The NLoS partial derivative non-line-of-sight vector can be expressed as

[0161]

[0162] According to equations (38) and (40), the value of equation (37) can be calculated, and the FIM and CRLB constraints can be derived according to the above formulas. CRLB is used as an indicator to evaluate the positioning performance of the VLCP system.

[0163] In an exemplary embodiment, the interruption probability is used as an indicator to evaluate the communication performance of the VLCP system. From equation (26), it can be seen that the achievable data rate is the CSI error e hThe achievable data rate is a function of the communication power and the positioning power (i.e., w p and w c ) are jointly determined by the RIS parameters. At the same time, the achievable data rate is a function of the RIS parameters. Therefore, under the condition of meeting the communication performance constraints, it is necessary to carefully adjust the impact of the RIS parameters on the achievable data rate. Since the achievable data rate is a function of the positioning error, the relationship between the achievable data rate and the positioning error can be used to calculate that the achievable data rate satisfies a probability distribution.

[0164] When the achievable data rate is less than a certain threshold, the system is in an interrupted state. The probability that the achievable data rate is less than the threshold is taken as the interruption probability, which can be expressed as

[0165] Pr{R c (w p ,w c ,G)≤R 0}≤P out , (42)

[0166] Where R 0 represents the quality of service constraint, indicating the threshold of the achievable data rate; P out It represents the maximum tolerable interruption probability, which is used as a measure of communication performance in the present invention.

[0167] From the above derivation, it can be seen that the achievable data rate is affected by both communication power and positioning power. The more power allocated to positioning, the higher the positioning accuracy, but the allocated communication power will be reduced, thereby reducing communication performance. Therefore, the power of the LED should be carefully allocated to make a trade-off between communication and positioning.

[0168] In one embodiment, when the VLCP system meets the QoS constraint (i.e., the achievable data rate meets the constraint of ensuring that the user communication rate is not interrupted), it is desired to minimize CRLB. At the same time, the power coefficient of communication and positioning and the allocation matrix of RIS are used as optimization parameters to minimize the optimization target. The optimization problem can be expressed as

[0169]

[0170] where e i is a column vector whose elements are all zero except the i-th element, represents non-negative and peak power constraints.

[0171] Adjustment of the LED power allocation and RIS allocation matrix will change the probability distribution of positioning error and CSI error, thereby changing the achievable data rate. Therefore, by optimizing the LED power allocation and RIS allocation matrix, the given interruption probability constraint P can be obtained. outThe optimal CRLB when . Due to the difficulty and non-convexity of the optimization problem, in order to solve the problem, this embodiment splits the problem into a power coefficient optimization sub-problem under a given RIS allocation matrix and a RIS optimization sub-problem under a given power coefficient. Combining these two sub-problems, this embodiment proposes an AO algorithm to solve the proposed optimization problem, and minimizes CRLB under the premise of satisfying the corresponding communication performance constraints, power constraints and RIS constraints.

[0172] The power coefficient optimization subproblem under a given RIS allocation matrix is ​​described as follows: Given a fixed RIS allocation matrix (assuming that it is in the tth iteration, the allocation matrix is ​​labeled G (t) ), we can focus on the optimization of communication and positioning power coefficients and minimize CRLB under the constraint of interruption probability. The main optimization problem can be simplified to

[0173]

[0174] Before introducing the optimization procedure, we would like to transform the non-convex constraints into a tractable form.

[0175] According to formula (26), the corresponding QoS constraint can be expressed as

[0176]

[0177] in Assumptions It can be seen that W c ≥0,rank(W c )=1, so formula (45) can be transformed into

[0178]

[0179] Therefore, the QoS constraints can be rewritten as

[0180]

[0181] Note that the probability constraints in the above formula are complex, so the present invention introduces a good convex approximation, namely, a method based on conditional value at risk (CVaR) to deal with the probability constraints. From formula (25), it can be seen that it is difficult to calculate a clear CSI error probability distribution based on the distribution of positioning error. However, we can calculate the expectation and variance of the CSI error based on the relationship between the CSI error and the positioning error. According to formula (25), the expectation of the CSI error of the i-th channel can be expressed as

[0182]

[0183] make represents the expectation of the CSI error vector. Similarly, the covariance matrix of the CSI error can be expressed as

[0184]

[0185] According to the CVaR method, the constraints in QoS can be written as

[0186]

[0187] Where D and λ are auxiliary variables, represents a real symmetric matrix of order 4, and

[0188]

[0189] Therefore, by using the transformation based on the CVaR method and ignoring the rank 1 constraint rank(W c )=1, the constraints in QoS can be transformed into several convex constraints by using semidefinite relaxation (SDR). The proof of the transformation can be found in existing literature.

[0190] Therefore, ignoring the rank 1 constraint, the power coefficient optimization subproblem given the RIS allocation matrix can be transformed into a semidefinite programming (SDP) problem, expressed as

[0191]

[0192] Similarly, assuming We can know that W p ≥0,rank(W p )=1. By ignoring the rank 1 constraint, the optimization subproblem can be characterized as

[0193]

[0194] Note that in this formula, the optimization objective and the power constraint are non-convex. The present invention transforms the optimization object into a convex function by using the successive convex approximation (SCA) method. The power constraint is transformed into an affine approximation by using the first-order Taylor series expansion.

[0195] The optimization objective can be conservatively transformed to

[0196]

[0197] From the above analysis, we can see that Tr(J u (W p ,G (t) ) is w p Therefore, the objective function can be rewritten as

[0198]

[0199] in and make According to the Cauchy-Schwarz inequality, we know that

[0200]

[0201] Therefore, the objective function can be conservatively transformed into

[0202]

[0203] Therefore, the optimization objective can be conservatively transformed into a p Convex function. By performing a first-order Taylor series expansion on the constraints in QoS, it can be approximately transformed into an affine constraint

[0204]

[0205] Where W c,0 With W p,0 represents any given initial value. Therefore, non-convex constraints can be approximately transformed into

[0206]

[0207] The power coefficient optimization subproblem can be transformed into a convex semidefinite programming (SDP) problem, expressed as

[0208]

[0209] This problem is convex and can be solved using the CVX toolbox in MATLAB. If the solution satisfies the rank-1 constraint rank(W c )=1 and rank(W p )=1, then the power coefficient vector w c and w p By p and W c If the constraints cannot be met, the Gaussian randomization method is used to find a solution that meets the constraints.

[0210] The RIS optimization subproblem under a given power coefficient is explained as follows: To avoid complex optimization of CRLB, the RIS parameters are optimized to increase the received power. This is because an increase in the received positioning power will lead to an improvement in positioning accuracy, while an increase in the received communication power will lead to an increase in the achievable data rate. Therefore, the RIS allocation matrix is ​​optimized to maximize the sum of the received powers. Given the power coefficient, the RIS optimization subproblem can be expressed as

[0211]

[0212] in and is the positioning and communication power coefficient at the t-th iteration, which is considered a fixed constant in the optimization process of the RIS allocation matrix. Without loss of generality, assume Therefore, the objective function can be defined as

[0213]

[0214] The target subproblem can be expressed as

[0215]

[0216] It can be found that the objective function is linear with respect to G. Due to the intensity modulation-direct detection scheme in VLC, w (t+1) The terms in are real-valued and non-negative, so f(G,w (t+1) ) n,i is monotonically increasing. The constraint can be rewritten as

[0217]

[0218] The optimization subproblem can be rewritten as

[0219]

[0220] According to equations (13) and (14), the objective function can be analyzed as follows:

[0221]

[0222] in Yes (t+1) The i-th item in When the LED subscript is selected according to the principle of , the equation holds. That is, the LED subscript can be determined as

[0223]

[0224] Therefore, based on this selection principle, the selected assignment matrix The nth row in can be expressed as

[0225]

[0226] You can see Satisfy the constraints of RIS itself. At the same time, the selected allocation matrix can maximize the objective function of the sub-problem. Therefore, under the condition of given power coefficient, the MRPC principle can be used to determine the RIS allocation matrix.

[0227] Based on the CVaR approximation, SCA and SDR methods, the power coefficient optimization subproblem for a given fixed RIS allocation matrix is ​​conservatively relaxed to a convex problem P1, which can be solved in polynomial time using the interior point method or the CVX toolbox. Based on this result, eigenvalue decomposition or Gaussian randomization is applied to bridge the gap between the relaxed solution and the optimal solution of the original problem. At the same time, the RIS allocation matrix optimization subproblem P2 for a given fixed power coefficient is solved based on MRPC to maximize the received power at the receiving end, thereby avoiding the complex optimization process of CRLB. Algorithm 1 summarizes the overall optimization process of the proposed optimization problem. In this algorithm, the initialization of the RIS allocation matrix is ​​based on the minimum distance criterion.

[0228]

[0229] The computational complexity analysis of the above algorithm 1 is as follows: Assuming the total number of iterations is Indicates that in each iteration, need operation, so the complexity is This is because in the RIS-assisted VLCP system proposed in the present invention, for any RIS unit, the worst case is calculated based on formula (67) Need to be done operation, and at the same time based on formula (68) it is necessary to set N r RIS units. Secondly, for the relaxed SDP problem, the CVX toolbox is used to solve it. The computational complexity in the worst case is where δ in is the accuracy of the interior point method. Therefore, the overall computational complexity of the algorithm proposed in the present invention can be expressed as

[0230] The following simulation experiments verify the effectiveness of the algorithm proposed in the present invention in solving the proposed optimization problem. At the same time, the effectiveness of RIS in improving VLCP performance is verified by simulation, especially in the absence of LoS links.

[0231] like Figure 5 As shown, a 4×4×3(m) 3RIS-assisted integrated multi-LED VLCP indoor room. The positions of the four LED lights are (1,-1,2.5)m, (3,1,2.5)m, (1,3,2.5)m and (3,3,2.5)m respectively. In the simulation, the position of the PD is set to (2.5,2.5,0.5)m. RIS is deployed on four walls to improve the localization and communication performance. The placement of occluders (users and non-users) follows a random uniform distribution. Users and non-users are modeled as cylinders with a diameter of 0.30m and a height of 1.65m. If the line from the LED to the PD intersects the cylinder, the receiver is considered to be occluded. All results are the average of more than 10,000 independent realizations.

[0232] Figure 5 (a) indicates that RIS is offline. Figure 5 (b) indicates that RIS is online. The pink short line indicates Figure 5 (a) and Figure 5 (b) Orientation of the RIS unit. The deployment of the RIS is constrained within four rectangular regions, centered on the center points of the four walls. Ignoring the depth of the walls, the center points of the four RIS are (2,0,1.5)m, (0,2,1.5)m, (2,4,1.5)m, and (4,2,1.5)m, and the area of ​​the RIS unit is 0.01m2. Assuming a field of view of 80°, the incident angle of the LoS link or the RIS reflected NLoS link can be verified to be within the field of view.

[0233] Figure 6 The possible negative impact of RIS on the positioning process of the VLCP system is pointed out. In the figure, we assume that the power of the LED is fully allocated to the positioning process to observe the impact of RIS on the positioning accuracy. We observe that the positioning performance improves with the increase of the signal-to-noise ratio (SNR), that is, the decrease of CRLB. This calibration is based on the prior information that changing the noise variance will produce an effect similar to that produced by adjusting the LED transmission power level. As can be seen from the figure, "CRLB LoS" means that the received positioning signal comes from only four LoS links, "CRLB NLoS" means that only the NLoS link reflected by the RIS provides the positioning signal (that is, the four LEDs are blocked), and "CRLB Sum" means that the received positioning signal is provided by all LoS links and the NLoS link constructed by RIS. As can be seen from the figure, the application of RIS reduces the positioning accuracy. This is because the position of the receiver and the position of the RIS will affect the sign of the partial derivative between the derivative constructed by RIS and the derivative constructed by LoS, thereby affecting the value of equation (37). Therefore, we propose a positioning scheme with LoS as the main and RIS as the auxiliary to avoid the negative positioning effect caused by RIS.

[0234] Figure 7The effectiveness of RIS in positioning performance when a LoS link is missing is verified. As can be seen from the figure, assuming that the LoS link given by LED 4 is blocked, the positioning performance drops sharply because LED 4 is closest to the receiver and plays an important role in the positioning process. Therefore, it can be seen from the figure that RIS can play a positive role in improving positioning accuracy when a LoS link is missing.

[0235] Considering the outage probability constraint, assuming that the noise power is constant, the relationship between CRLB and rate threshold under a given outage probability is studied through simulation. Figure 8 It means that given the outage probability and noise power 10log 10 (1 / B p N 0 )=130(dB), the relationship between CRLB and rate threshold. As can be seen from the figure, the addition of RIS improves positioning performance compared to the system using only LoS transmission. This is because the use of RIS can provide NLoS channel gain to assist communication, thereby relaxing the requirements for communication power. Based on this, more positioning power can be allocated to improve positioning performance. At the same time, an increase in the probability of interruption will improve positioning accuracy, because an increase in the probability of interruption will relax the requirements for communication, allowing less communication allocation power and more positioning allocation power to improve CRLB.

[0236] The present invention selects the cumulative distribution function (CDF) of the achievable data rate as a standard for measuring communication performance. Figure 9 Indicates that when R is satisfied c =CDF of the data rate that can be achieved under the interruption probability of the rate threshold of 200Mbps. In the figure, "LoS" means that the channel gain is provided only by the LoS channel, and "LoS+NLoS" means that the transmission is provided by both the LoS link and the NLoS link constructed by RIS. It can be seen from the figure that when the probability requirements are met, the greater the power allocated to the communication, the higher the interruption probability and the better the communication performance. At the same time, it can be seen that the application of RIS can significantly improve the communication performance of the system. This is because RIS provides a considerable channel gain.

[0237] The present invention proposes a positioning-centric RIS-assisted multi-LED VLCP system to realize the functions of VLC and VLP and reduce the sensitivity to visible light LoS links. The mechanism of combining communication and positioning in the VLCP system and the timing of RIS operation are explained. The scheme aims to maximize the advantages of RIS in communication while avoiding adverse effects on positioning. In addition, when LoS is not available, RIS is used to supplement positioning. The present invention derives the CRLB of the positioning result when considering the RIS reflection channel gain, and takes the maximum interruption probability as a constraint on the communication performance. Under the premise of satisfying the maximum tolerable interruption probability, RIS parameter restrictions and total transmission power constraints, with the goal of maximizing positioning accuracy, RIS parameters and transmission power are jointly optimized to minimize CRLB. For non-convex optimization problems, AO algorithm, CVaR-based probability transformation, SCA technology and MRPC principle are proposed to optimize RIS parameters and transmission power. Simulation results show that the application of RIS can effectively improve the communication performance of the system, reduce the requirements for communication power, and thus improve the positioning performance of the system.

[0238] Figure 10 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 10As shown, the electronic device may include: a processor (processor) 1001, a communication interface (Communications Interface) 1002, a memory (memory) 1003 and a communication bus 1004, wherein the processor 1001, the communication interface 1002, and the memory 1003 communicate with each other through the communication bus 1004. The processor 1001 can call the logic instructions in the memory 1003 to execute the RIS parameter configuration and power allocation method, which includes: modeling the matching relationship between the LED, the RIS unit and the receiver, and determining the first constraint condition according to the matching relationship; determining the constraint condition that the transmitted signal in the VLCP system needs to meet, recorded as the second constraint condition; under the matching relationship, determining the reachable data rate constraint condition that the VLCP system needs to meet, recorded as the third constraint condition; the reachable data rate is jointly determined by the communication power allocation coefficient and the positioning power allocation coefficient of the LED; using the Cramer-Rao lower bound as the positioning performance evaluation index of the VLCP system, thereby converting the RIS parameter configuration and power allocation problem into a problem of optimizing the positioning performance evaluation index under the joint constraints of the first constraint condition, the second constraint condition and the third constraint condition, and finding the minimum value of the positioning performance evaluation index. The matching relationship, communication power allocation coefficient and positioning power allocation coefficient corresponding to the minimum value of the positioning performance evaluation index are the optimal RIS parameter configuration and power allocation strategy. In addition, when the logic instructions in the above-mentioned memory 1003 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0239] An embodiment of the present invention further provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the RIS parameter configuration and power allocation methods provided in the above-mentioned method embodiments.

[0240] An embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the RIS parameter configuration and power allocation methods provided by the above-mentioned method embodiments are implemented.

[0241] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0242] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A VLCP system based on multiple LEDs, comprising a transmitter and a receiver, characterized in that: Also includes: Intelligent metasurface RIS; The transmitter includes a controller and N L LEDs that are not collinear, N L ≥3; Each of the LEDs is used to emit a light signal, so that the transmitter can modulate the positioning signal and the communication signal based on the light signal; The controller is used to control the RIS to be in a working state during the communication process; when the line-of-sight link is not blocked, control the RIS to be in a closed state during the positioning process; when the line-of-sight link is blocked, control the RIS to provide a non-line-of-sight link capable of transmitting a positioning signal to the receiver; The receiver is used to locate the position information of the receiver according to the positioning signal and transmit the position information to the transmitter; The transmitter is used to estimate channel state information according to the position information of the receiver, and transmit the communication signal to the receiver according to the estimated channel state information.

2. The RIS parameter configuration and power allocation method of a VLCP system based on multiple LEDs as claimed in claim 1, characterized in that: include: Modeling a matching relationship among the LED, the RIS unit, and the receiver, and determining a first constraint condition according to the matching relationship; Determine the constraint conditions that the transmitted signal in the VLCP system needs to meet, recorded as the second constraint condition; Under the matching relationship, determine the achievable data rate constraint condition that the VLCP system needs to meet, which is recorded as the third constraint condition; the achievable data rate is jointly determined by the communication power allocation coefficient and the positioning power allocation coefficient of the LED; The Cramer-Rao lower bound is used as the positioning performance evaluation index of the VLCP system, so that the RIS parameter configuration and power allocation problem is converted into a problem of optimizing the positioning performance evaluation index under the common constraints of the first constraint condition, the second constraint condition and the third constraint condition, and the minimum value of the positioning performance evaluation index is obtained. The matching relationship, communication power allocation coefficient and positioning power allocation coefficient corresponding to the minimum value of the positioning performance evaluation index are the optimal RIS parameter configuration and power allocation strategy.

3. The RIS parameter configuration and power allocation method according to claim 2, characterized in that: Finding the minimum value of the positioning performance evaluation index specifically includes: The problem of optimizing the positioning performance evaluation index under the common constraints of the first constraint condition, the second constraint condition and the third constraint condition is split into a first optimization sub-problem and a second optimization sub-problem, so as to obtain the optimal value of the positioning performance evaluation index by adopting an alternating optimization algorithm; Among them, the first optimization sub-problem is: under the first constraint condition, given the matching relationship between the LED, RIS unit and the receiver, solve the optimal communication power allocation coefficient and positioning power allocation coefficient that meet the second constraint condition and the third constraint condition; the second optimization sub-problem is: under the second constraint condition and the third constraint condition, given the communication power allocation coefficient and the positioning power allocation coefficient, solve the optimal matching relationship between the LED, RIS unit and the receiver that meets the first constraint condition.

4. The RIS parameter configuration and power allocation method according to claim 3, characterized in that: When solving the first optimization sub-problem, the matching relationship between the LED, RIS unit and receiver is initialized based on the minimum distance criterion; the distance refers to the distance from the LED transmission signal from the LED to the RIS unit and then from the RIS unit to the receiver.

5. The RIS parameter configuration and power allocation method according to any one of claims 2 to 4, characterized in that: The second constraint condition includes a non-negativity condition of the transmitted signal, a peak power constraint condition of the transmitted signal, and an average power constraint condition of the transmitted signal.

6. The RIS parameter configuration and power allocation method according to any one of claims 2 to 4, characterized in that: The third constraint condition is that the interruption probability of the communication signal should not be greater than the maximum tolerable interruption probability; wherein the interruption probability refers to the probability that the achievable data rate is not greater than the quality of service constraint.

7. The RIS parameter configuration and power allocation method according to claim 6, characterized in that: When solving the first optimization sub-problem, the optimal communication power allocation coefficient and positioning power allocation coefficient are derived using a method based on conditional risk value and a method based on continuous convex approximation.

8. The RIS parameter configuration and power allocation method according to claim 3, characterized in that: When solving the second optimization sub-problem, the maximum received power selection principle is used to derive the optimal matching relationship between the LED, the RIS unit and the receiver.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method according to any one of claims 2 to 8 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 2 to 8 is implemented.

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