Wireless optical downlink multiple access communication method based on optical smart reflective surface

Abstract

The application discloses a wireless optical downlink multiple access communication method based on an optical intelligent reflecting surface, and the method comprises the following steps: optimizing at least one user group by using a preset optimization constraint, and determining a multiple access mode between multiple users according to the optimized at least one user group; obtaining optimal optical intelligent reflecting surface parameters and optimal transmission end transmission power distribution coefficients reflected by the intelligent surface; combining the optimal optical intelligent reflecting surface parameters, the optimal transmission end transmission power distribution coefficients and the multiple access mode to generate a corresponding multiple user signal transmission strategy, so as to perform signal transmission by using the multiple user signal transmission strategy. Thus, the technical problem that the wireless optical communication system communication is prone to interruption is solved, the system performance deterioration caused by the non-ideality of the serial interference cancellation is reduced, the spatial multiplexing gain of the wireless optical communication is improved, the channel capacity of the wireless optical communication system is increased, and the multi-user access capability of the wireless optical communication system is improved.

Description

Technical Field

[0001] This application relates to the field of intelligent reflection and multiple access communication technology, and in particular to a wireless optical downlink multiple access communication method based on an optical intelligent reflective surface. Background Technology

[0002] Against the backdrop of explosive growth in communication data traffic and increasingly congested communication bands, Visible Light Communication (VLC) is considered a promising future 6G communication technology due to its license-free operation and the widespread availability of LEDs (Light Emitting Diodes). It can modulate signals onto electromagnetic waves with wavelengths ranging from 480 nanometers to 750 nanometers, and its nearly 400 THz communication band can significantly increase the system capacity of visible light communication systems. Furthermore, because VLC uses LEDs as the transmitter and photodetectors (PDs) as the receiver, its energy efficiency at both ends is significantly better than that of RF (Radio Frequency) communication. Therefore, VLC is considered to have enormous potential in green and secure communication.

[0003] NOMA (Non-Orthogonal Multiple Access) technology, a key technology in related fields, is crucial for mMTC (massive Machine Type Communication) and can be used in multiple domains, including spatial, code, time, and frequency domains. However, PDMA (Power-Domain Non-Orthogonal Multiple Access) has the widest applicability among non-orthogonal multiple access technologies because it can be integrated with many existing technologies and offers high encoding and decoding flexibility. Specifically, PDMA allows multiple users to simultaneously use the same spectrum resources. At the transmitter, SC (Superposition Coding) is used to superimpose and transmit the multi-user signals, allocating different transmit powers according to the user's channel conditions. At the receiver, the user decodes the signal using SIC (Successive Interference Cancellation).

[0004] However, in related technologies, NOMA's performance is sometimes inferior to OMA's, and wireless optical communication systems are prone to interruption when obstructed by obstacles, which needs to be improved. Summary of the Invention

[0005] This application is based on the inventor's knowledge and discoveries regarding the following issues: Intelligent Reflection Surfaces (IRS), planar arrays composed of numerous low-cost passive reflective elements, have attracted widespread interest in radio frequency (RF) communications in recent years. By controlling the reflection characteristics of tunable elements, IRS can adaptively reconfigure the radio electromagnetic environment, thereby altering the wireless communication channel. Researchers have investigated the optimization of IRS configurations to improve system performance, including maximizing sum and rate, and minimizing outage probability. Furthermore, since visible light can be easily blocked, Optical Intelligent Reflection Surfaces (OIRS) can leverage their ability to provide reflection paths to help VLC systems overcome their limitations. OIRS can be implemented using microelectromechanical systems (MEMS) manipulated mirror arrays or optical reflective materials, and existing research has demonstrated their important role in improving the performance of visible light communication systems. However, due to the characteristics of visible light, such as its different propagation characteristics compared to RF signals, and its non-negative and real-valued nature, the impact of OIRS on VLC systems differs significantly from the impact of IRS on RF communication systems.

[0006] Meanwhile, hybrid NOMA and OMA communication can significantly improve the performance of VLC systems, including system capacity and bit error rate. Considering that NOMA has certain requirements for the quality differences of multi-user channels, while OIRS has the ability to modify wireless channels, applying NOMA and OIRS together in visible light communication systems can improve the spatial multiplexing gain of the system, while increasing the capacity of the wireless optical communication system and reducing the bit error rate, making it a very promising technology.

[0007] In summary, this application provides a wireless optical downlink multiple access communication method based on an optical intelligent reflective surface to solve the technical problem in related technologies where wireless optical communication systems are easily interrupted when obstructed by obstacles. It also reduces the system performance degradation caused by the non-ideal elimination of serial interference, improves the spatial multiplexing gain of wireless optical communication, increases the channel capacity of wireless optical communication systems, and enhances the multi-user access capability of wireless optical communication systems.

[0008] The first aspect of this application provides a wireless optical downlink multiple access communication method based on an optical smart reflective surface, comprising the following steps: optimizing at least one user group using preset optimization constraints, and determining the multiple access mode among multiple users based on the optimized at least one user group; obtaining the optimal optical smart reflective surface parameters and the optimal transmitter power allocation coefficient; and generating a corresponding multi-user signal transmission strategy by combining the optimal optical smart reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access mode, so as to use the multi-user signal transmission strategy for signal transmission.

[0009] Optionally, in one embodiment of this application, the step of optimizing user packets using optimization constraints and determining multiple access methods among multiple users includes: calculating the line-of-sight path channel gain and the smart surface reflection path channel gain for each user based on channel state information of the line-of-sight path and the smart surface reflection path, combined with the position information of the transmitter, the optical smart reflective surface, and the receiver; optimizing the user packets using a preset optimization method based on the line-of-sight path channel gain of each user and a preset target, combined with the preset optimization constraints; and matching the optimal multiple access method based on the optimized user packets.

[0010] Optionally, in one embodiment of this application, the optimal multiple access method is to use a non-orthogonal multiple access method or an orthogonal multiple access method for multiple user signals in the same group, and an orthogonal multiple access method for multiple user signals in different groups; wherein, the non-orthogonal multiple access method includes at least one of power domain non-orthogonal multiple access method, code domain non-orthogonal multiple access method, and sparse coded multiple access method; the orthogonal multiple access method includes at least one of time domain orthogonal access method, frequency domain orthogonal access method, and orthogonal frequency division multiple access method.

[0011] Optionally, in one embodiment of this application, the preset optimization constraints include at least one of the following: non-negative real number constraints of optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user sum rate constraints, and single-user rate constraints.

[0012] Optionally, in one embodiment of this application, the preset objective includes at least one of minimizing the bit error rate of the wireless optical communication system, maximizing the channel capacity, and maximizing the minimum user rate.

[0013] Optionally, in one embodiment of this application, obtaining the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection includes: optimizing the optical intelligent reflective surface parameters based on the channel state information of the line-of-sight path and the intelligent surface reflection path, combined with the position information of the transmitter, the optical intelligent reflective surface, and the receiver, to obtain the optimal optical intelligent reflective surface parameters; and adjusting the transmitter power allocation coefficients of each user at the transmitter end according to the total channel gain of each user to obtain the optimal transmitter power allocation coefficients.

[0014] Optionally, in one embodiment of this application, the method further includes: adjusting the optical smart reflective surface parameters based on a user's change instruction; and changing the smart surface reflection path signal of the wireless optical communication based on the optical smart reflective surface parameters to change the total channel gain.

[0015] Optionally, in one embodiment of this application, changing the smart surface reflection path signal of wireless optical communication based on the optical smart reflective surface parameters to change the total channel gain includes: adjusting the orientation angle or control voltage of the reflective unit of the optical smart reflective surface; aligning the reflective unit with the corresponding LED of the transmitter and the receiver using a codebook lookup method or a geometric calculation method, so that the reflective unit reflects the light beam emitted by the LED to the corresponding receiver, thereby adjusting the alignment relationship between the transmitter, the optical smart reflective surface and the receiver in the optical smart reflective surface parameters.

[0016] A second aspect of this application provides a wireless optical downlink multiple access communication device based on an optical smart reflective surface, comprising: a packet module, configured to optimize at least one user packet using preset optimization constraints, and determine a multiple access mode among multiple users based on the optimized at least one user packet; an acquisition module, configured to acquire the optimal optical smart reflective surface parameters and the optimal transmitter power allocation coefficient of the smart surface reflection; and a communication module, configured to combine the optimal optical smart reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access mode to generate a corresponding multi-user signal transmission strategy, so as to use the multi-user signal transmission strategy for signal transmission.

[0017] Optionally, in one embodiment of this application, the grouping module includes: a calculation unit, used to calculate the line-of-sight path channel gain and the smart surface reflection path channel gain for each user based on the channel state information of the line-of-sight path and the smart surface reflection path, combined with the position information of the transmitter, the optical smart reflective surface, and the receiver; a grouping unit, used to optimize the user grouping using a preset optimization method based on the line-of-sight path channel gain of each user and a preset target, combined with the preset optimization constraints; and a matching unit, used to match the optimal multiple access method based on the optimized user grouping.

[0018] Optionally, in one embodiment of this application, the optimal multiple access method is to use a non-orthogonal multiple access method or an orthogonal multiple access method for multiple user signals in the same group, and an orthogonal multiple access method for multiple user signals in different groups; wherein, the non-orthogonal multiple access method includes at least one of power domain non-orthogonal multiple access method, code domain non-orthogonal multiple access method, and sparse coded multiple access method; the orthogonal multiple access method includes at least one of time domain orthogonal access method, frequency domain orthogonal access method, and orthogonal frequency division multiple access method.

[0019] Optionally, in one embodiment of this application, the preset optimization constraints include at least one of the following: non-negative real number constraints of optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user sum rate constraints, and single-user rate constraints.

[0020] Optionally, in one embodiment of this application, the preset objective includes at least one of minimizing the bit error rate of the wireless optical communication system, maximizing the channel capacity, and maximizing the minimum user rate.

[0021] Optionally, in one embodiment of this application, the acquisition module includes: an optimization unit, configured to optimize the optical intelligent reflective surface parameters based on the channel state information of the line-of-sight path and the intelligent surface reflection path, combined with the position information of the transmitter, the optical intelligent reflective surface and the receiver, to obtain the optimal optical intelligent reflective surface parameters; and a first adjustment unit, configured to adjust the transmit power allocation coefficient of each user at the transmitter end according to the total channel gain of each user, to obtain the optimal transmitter transmit power allocation coefficient.

[0022] Optionally, in one embodiment of this application, it further includes: an adjustment module, configured to adjust the optical intelligent reflective surface parameters based on a user's change instruction, and to change the intelligent surface reflection path signal of wireless optical communication based on the optical intelligent reflective surface parameters, so as to change the total channel gain.

[0023] Optionally, in one embodiment of this application, the adjustment module includes: a second adjustment unit, used to adjust the orientation angle or control voltage of the reflective unit of the optical intelligent reflective surface; and a third adjustment unit, used to align the reflective unit with the corresponding LED of the transmitter and the receiver using a codebook lookup method or a geometric calculation method, so that the reflective unit reflects the light beam emitted by the LED to the corresponding receiver, thereby adjusting the alignment relationship between the transmitter, the optical intelligent reflective surface and the receiver in the parameters of the optical intelligent reflective surface.

[0024] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the wireless optical downlink multiple access communication method based on an optical intelligent reflective surface as described in the above embodiments.

[0025] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described wireless optical downlink multiple access communication method based on an optically intelligent reflective surface.

[0026] This application embodiment can optimize user groups and determine the multiple access method among multiple users based on at least one optimized user group. It optimizes the optical intelligent reflective surface parameters and the transmitter power allocation coefficient, thereby combining the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access method to generate a corresponding multi-user signal transmission strategy. Utilizing this strategy for signal transmission can effectively reduce the mean square error and bit error rate of the wireless optical communication system, increase its system capacity, enhance multi-user access capabilities, and reduce the impact of obstacles on wireless optical communication. This effectively improves the spatial multiplexing gain, increases the channel capacity, and enhances multi-user access capabilities of the wireless optical communication system. Therefore, it solves the technical problem in related technologies where wireless optical communication systems are easily interrupted when obstructed by obstacles.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a wireless optical downlink multiple access communication method based on an optical smart reflective surface according to an embodiment of this application; Figure 2 This is a schematic diagram illustrating the principle of a wireless optical downlink multiple access communication method based on an optical smart reflective surface according to an embodiment of this application; Figure 3 This is a signal processing block diagram according to one embodiment of the present application; Figure 4 This is a schematic diagram of a genetic algorithm for a wireless optical downlink multiple access communication method based on an optical smart reflective surface according to an embodiment of this application; Figure 5 This is a schematic diagram of a wireless optical downlink multiple access communication device based on an optical smart reflective surface, according to an embodiment of this application. Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0030] The following describes a wireless optical downlink multiple access communication method based on an optically intelligent reflective surface according to embodiments of this application, with reference to the accompanying drawings. Addressing the technical problem mentioned in the background section of the related technologies where wireless optical communication systems are easily interrupted by obstacles, this application provides a wireless optical downlink multiple access communication method based on an optically intelligent reflective surface. In this method, user group optimization is performed, and the multiple access mode among multiple users is determined based on at least one optimized user group. The parameters of the optically intelligent reflective surface and the transmitter power allocation coefficient are optimized. By combining the optimal optically intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access mode, a corresponding multi-user signal transmission strategy is generated. Using this multi-user signal transmission strategy for signal transmission can effectively reduce the mean square error and bit error rate of the wireless optical communication system, increase the system capacity, improve multi-user access capability, and reduce the impact of obstacles on wireless optical communication. This effectively improves the spatial multiplexing gain, increases the channel capacity of the wireless optical communication system, and enhances multi-user access capability. Therefore, it solves the technical problem in the related technologies where wireless optical communication systems are easily interrupted by obstacles.

[0031] Specifically, Figure 1 This is a flowchart illustrating a wireless optical downlink multiple access communication method based on an optical intelligent reflective surface, provided in an embodiment of this application.

[0032] like Figure 1 As shown, the wireless optical downlink multiple access communication method based on an optical smart reflective surface includes the following steps: In step S101, at least one user group is optimized using preset optimization constraints, and the multiple access method among multiple users is determined based on the optimized at least one user group.

[0033] In actual implementation, the embodiments of this application can optimize at least one user group using preset optimization constraints, thereby determining the multiple access mode among multiple users based on the grouping results, such as the multiple access mode among multiple users within the same group and the multiple access mode among multiple users outside the same group, thereby providing reliable data support for the realization of wireless optical downlink hybrid multiple access communication based on optical intelligent reflective surfaces.

[0034] The preset optimization constraints will be explained below.

[0035] Optionally, in one embodiment of this application, the preset optimization constraints include at least one of the following: non-negative real number constraints of optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user sum rate constraints, and single-user rate constraints.

[0036] Here, the preset optimization constraints are explained.

[0037] As one possible approach, in the user grouping optimization, this application embodiment can obtain the line-of-sight path channel gain based on channel state information, and then use a genetic algorithm to optimize user groups based on the line-of-sight path channel gain, thereby achieving optimization of a specific objective. Furthermore, based on optimization constraints, such as non-negative real number constraints of optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user sum rate constraints, and single-user rate constraints, user grouping optimization can be achieved through optimization methods such as alternating optimization algorithms, joint optimization algorithms, and genetic algorithms.

[0038] Optionally, in one embodiment of this application, optimizing user packets using optimization constraints and determining multiple access methods among multiple users includes: calculating the line-of-sight path channel gain and the smart surface reflection path channel gain for each user based on channel state information of the line-of-sight path and the smart surface reflection path, combined with the position information of the transmitter, the optical smart reflective surface, and the receiver; optimizing user packets using a preset optimization method based on the line-of-sight path channel gain and a preset target, combined with preset optimization constraints; and matching the optimal multiple access method based on the optimized user packets.

[0039] Specifically, the method for optimizing user groups using optimization constraints and determining the multiple access method among multiple users in this application embodiment may include the following steps: S1: Obtain line-of-sight path and smart surface path channel state information; For example, embodiments of this application can utilize channel estimation techniques to obtain channel state information for line-of-sight paths and smart surface reflection paths. The channel estimation techniques can be based on time-domain training sequences or pilot sequences, such as least squares estimation or (linear) minimum mean square error estimation. Those skilled in the art can choose according to the actual situation, and no specific limitations are imposed here.

[0040] Furthermore, channel estimation for line-of-sight paths needs to be performed with the optical smart reflective surface turned off; channel estimation for smart surface reflection paths can be performed by sequentially turning on each element of the metasurface and estimating the channel response of the reflection path through each element's surface.

[0041] S2: Acquire the position information of the transmitter, optical smart reflective surface, and receiver; In the embodiments of this application, the position information of the transmitter and the optical intelligent reflective surface is the prior information of the system and remains unchanged during the optimization process. In the specific implementation process, technicians can use indoor wireless positioning technology to estimate the position information of the receiver, including infrared indoor positioning technology, visible light positioning technology, ultra-wideband positioning technology, etc.

[0042] S3: For a specific target, use an optimization algorithm to optimize user groups and determine the multi-access method between users.

[0043] It should be noted that in the embodiments of this application, the number of transmitters is one, the number of receivers can be multiple, and the number of units of the optical intelligent reflective surface can be zero or multiple.

[0044] Optionally, in one embodiment of this application, the preset objective includes at least one of minimizing the bit error rate of the wireless optical communication system, maximizing the channel capacity, and maximizing the minimum user rate.

[0045] In this application embodiment, the preset objective, i.e. the specific objective, can be the minimization of the bit error rate of the wireless optical communication system, the maximization of system capacity, or the maximization of the minimum rate for multiple users, etc., so as to optimize user packets according to the line-of-sight path channel gain of each user and the preset objective, combined with preset optimization constraints, and using a preset optimization method; and matching the optimal multiple access mode based on the optimized user packets.

[0046] Optionally, in one embodiment of this application, the optimal multiple access method is to use a non-orthogonal multiple access method or an orthogonal multiple access method for multiple user signals in the same group, and an orthogonal multiple access method for multiple user signals in different groups; wherein, the non-orthogonal multiple access method includes at least one of power domain non-orthogonal multiple access method, code domain non-orthogonal multiple access method, and sparse coded multiple access method; the orthogonal multiple access method includes at least one of time domain orthogonal access method, frequency domain orthogonal access method, and orthogonal frequency division multiple access method.

[0047] In actual implementation, such as Figure 2 The diagram shown illustrates the principle of a wireless optical downlink multiple access communication method based on an optical intelligent reflective surface. Embodiments of this application can use... and This indicates the number of receivers and the total transmit bandwidth. Divide into equal parts There are 1 sub-channels, each with a bandwidth of 1. ,use This indicates the number of intelligent reflective surface units serving each sub-channel. Information is transmitted between each sub-channel using orthogonal multiple access (OMA). Information from two users is transmitted within each sub-channel, and users can use either OMA or non-OMA access depending on the optimization objective.

[0048] It should be noted that, in the embodiments of this application, the orthogonal multiple access method adopts the frequency division multiple access scheme.

[0049] The embodiments of this application can use the total system channel capacity as the optimization target. Since the Shannon formula cannot be directly used in visible light communication systems, the achievable rate lower bound of the VLC system can be used as the optimization target. In particular, when the... The communication bandwidth occupied by each user is At that time, its achievable lower bound is: , in, Indicates the first SINR (signal-to-interference-plus-noise ratio) of each user receiver.

[0050] The embodiments of this application can be used and Let represent the weaker user line-of-sight path channel gain and the stronger user line-of-sight path channel gain within a sub-channel, respectively. Then, when two users transmit information using orthogonal multiple access (OMA) within the sub-channel, the achievable rate for both users is: , , in, and The SINR at the receiver when weak users and strong users use orthogonal multiple access, respectively, can be expressed as: , , in, This indicates the transmitter's transmit power in each sub-channel. This represents the Gaussian noise power at the receiver.

[0051] When two users in a subchannel transmit information using a non-orthogonal multiple access method, the achievable rate for the two users is: , , in, and The SINR at the receiver when weak users and strong users use non-orthogonal multiple access, respectively, can be expressed as: , , in, This represents the transmit power allocation factor for weak users. , This represents the residual interference coefficient introduced by the non-ideal SIC. .

[0052] The algorithms used in the embodiments of this application include genetic algorithms to obtain optimal user groups. The multiple access method among users in the same group can be determined according to a multi-user rate criterion or a single-user rate criterion. The multi-user rate criterion means that when... When two users are in a non-orthogonal multiple access mode, orthogonal multiple access mode is used; the single-user rate criterion means that when and If two users use a non-orthogonal multiple access method, then an orthogonal multiple access method is used.

[0053] It should be noted that those skilled in the art can choose optimization criteria based on the actual situation, and no specific restrictions are imposed here.

[0054] Therefore, embodiments of this application can use the proposed genetic algorithm to obtain user groups based on the estimated line-of-sight path channel state information, and determine the multiple access mode between users according to different criteria, thereby achieving optimization for a specific objective.

[0055] Furthermore, in the embodiments of this application, the non-orthogonal multiple access methods include, but are not limited to, power domain non-orthogonal multiple access methods, code domain non-orthogonal multiple access methods, and sparse coded multiple access methods; Orthogonal multiple access methods include, but are not limited to, time-domain orthogonal access, frequency-domain orthogonal access, and orthogonal frequency division multiple access.

[0056] In step S102, the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection are obtained.

[0057] As one possible implementation method, the optimization algorithm used in the embodiments of this application includes alternating optimization of the optical intelligent reflective surface matrix and the transmitter power allocation coefficient. Each sub-process can employ algorithms including Lagrange dual optimization, obtaining closed-form optimal solutions by solving KKT conditions, stochastic gradient descent algorithm, simulated degradation, etc., or use joint optimization of the optical intelligent reflective surface matrix and the transmitter power allocation coefficient to achieve optimization of a specific objective.

[0058] It should be noted that those skilled in the art can choose optimization objectives, constraints and methods to implement wireless optical communication according to the actual situation, and no specific restrictions are imposed here.

[0059] Optionally, in one embodiment of this application, obtaining the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection includes: optimizing the optical intelligent reflective surface parameters based on channel state information of the line-of-sight path and the intelligent surface reflection path, combined with the position information of the transmitter, the optical intelligent reflective surface, and the receiver, to obtain the optimal optical intelligent reflective surface parameters; and adjusting the transmitter power allocation coefficients of each user at the transmitter end according to the total channel gain of each user to obtain the optimal transmitter power allocation coefficients.

[0060] Furthermore, such as Figure 3 The diagram shown is a signal processing block diagram according to an embodiment of this application. Embodiments of this application can use... These represent the number of intelligent reflective surface units serving each sub-channel. According to the principle of receiver-side serial interference cancellation, the receiver demodulates signals in descending order of strength. After removing other demodulated user signals from the original signal, user signals with weaker strength than the receiver's own are considered interference. The signal-to-interference-plus-noise ratio (SIR) of the two user receivers can be expressed as: , , in, and These represent the total channel gain for strong users and weak users, respectively. This refers to the transmitter's SNR (signal-to-noise ratio). This indicates the transmitter's transmit power in each sub-channel. This represents the noise power of the subchannel.

[0061] Specifically, embodiments of this application can utilize a binary correlation matrix between the transceiver and the various units of the smart reflective surface. As an optical intelligent reflective surface matrix. Among them, the correlation matrix... The number of rows represents the number of smart reflective surface units, and the number of columns represents the number of receivers. When a matrix element is "1", it indicates that there is a correlation between the smart reflective surface unit and the corresponding receiver, that is, the smart surface reflection path composed of the transmitter, smart reflective surface unit, and receiver conforms to the generalized Snell's law, and the smart surface can reflect the signal from the transmitter to the designated receiver; when it is "0", it indicates that the smart reflective surface unit and the corresponding receiver are not aligned.

[0062] Based on the Lambert radiation model, the embodiments of this application define a transmitter and a receiver. The channel gain of the line-of-sight path is Then the line-of-sight path channel gain It can be represented as: .

[0063] Based on the Lambert radiation model, the embodiments of this application define a smart reflective surface unit. and receiver The channel gain of the constructed smart surface reflection path is The channel gain of the smart surface reflection path It can be represented as: , in .

[0064] Therefore, based on the optical intelligent reflective surface matrix According to the definition, the total channel gain for two users within the sub-channel in this application embodiment can be obtained as: , .

[0065] in, , , , , , These are the line-of-sight path channel gain, smart surface reflection path channel gain, and smart reflective surface correlation vector corresponding to the two user IDs, respectively.

[0066] Furthermore, in such Figure 2In the wireless optical downlink hybrid multiple access communication scenario based on intelligent reflective surfaces shown, the central control system in this embodiment of the application uses an iterative optimization algorithm to allocate the optical intelligent reflective surface and the transmission power coefficient to maximize the total reachability of the system.

[0067] In other words, a nonnegative matrix By representing the optical intelligent reflective surface parameters and fixing the optical intelligent reflective surface parameters in the denominator of the achievable rate expression using the results of the previous iteration, the original problem can be transformed into a problem concerning... This is a convex, linearly constrained quadratic optimization problem. The transformed SINR expression for the two users is: , , Among them, superscript Representing the The results of the round of iterations.

[0068] The embodiments of this application can be solved using classical convex optimization algorithms, including but not limited to the projection gradient algorithm and the original dual algorithm. In each iteration, the optical intelligent reflective surface parameters of the previous iteration are used as fixed values, and the optical intelligent reflective surface parameters can be obtained when the iteration converges.

[0069] The transmit power allocation coefficient needs to be optimized based on the optimized optical intelligent reflective surface parameters. Those skilled in the art can use methods such as fixed values, channel quality-based allocation, or received power difference to allocate the transmit power.

[0070] In particular, if the total channel quality ranking of each user differs from the line-of-sight path channel quality ranking after the optical intelligent reflective surface parameters are optimized, then each user needs to be renumbered according to the total channel quality ranking, and then the aforementioned optimization process is repeated to complete the optimization of the optical intelligent reflective surface and the transmit power allocation coefficient.

[0071] Therefore, embodiments of this application can use the proposed iterative optimization algorithm to obtain the optical intelligent reflective surface matrix parameters and transmit power allocation coefficients based on the estimated channel state information, thereby achieving optimization for a specific objective.

[0072] In step S103, the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access method are combined to generate a corresponding multi-user signal transmission strategy, so as to use the multi-user signal transmission strategy for signal transmission.

[0073] In some embodiments, after optimizing a specific target by setting the optical intelligent reflective surface matrix parameters and the transmission power allocation coefficient, the embodiments of this application further, based on the transmission power allocation coefficients and multiple access methods of each user in the same group, weighted summation of the user signals in the group using a non-orthogonal multiple access scheme using superposition coding, and superposition transmission at the transmitting end; the user signals in the group using an orthogonal multiple access scheme are directly transmitted in an orthogonal multiple access manner; and user signals from different groups are transmitted in an orthogonal multiple access manner.

[0074] For each sub-channel, in this embodiment of the application, the user with the stronger line-of-sight path channel gain can be named... Usernames with weaker line-of-sight path channel gain are named For users using a non-orthogonal multiple access scheme, the multi-user coded sequences to be transmitted are weighted and summed according to the optimized transmit power allocation coefficient to obtain the transmitter's transmit signal, enabling the signals of different users to be superimposed and transmitted at the transmitting end.

[0075] Specifically, embodiments of this application can combine the signals of two users. and According to the power distribution factor respectively and The transmitted signal from the transmitter is obtained by performing a weighted summation. : , Furthermore, in the specific implementation process, those skilled in the art can select a suitable constellation mapping method according to the actual situation. After propagation through the line-of-sight path and the smart surface reflection path, the signal reaching the receiver can be expressed as: , , in, The receiver's zero-mean white Gaussian noise, .

[0076] For users in the same group using an orthogonal multiple access scheme, frequency division multiple access is used for transmission in the embodiments of this application, and the transmission signals of the two users are... and They are orthogonal in the frequency domain, have the same transmission power, and occupy the same bandwidth, which will not be elaborated further here.

[0077] Optionally, in one embodiment of this application, the method further includes: adjusting the optical intelligent reflective surface parameters based on the user's change instruction; and changing the intelligent surface reflection path signal of the wireless optical communication based on the optical intelligent reflective surface parameters to change the total channel gain.

[0078] After the transmitting end completes the encoding of the transmitted signal, the embodiments of this application can further improve the system performance by actively changing the total channel gain by setting the optical intelligent reflective surface parameters to change the intelligent surface reflection path signal of wireless optical communication.

[0079] In other words, the embodiments of this application can utilize the optical intelligent reflective surface parameters to indicate the alignment relationship between the reflective surface unit and the receiver. Based on the optimized optical intelligent reflective surface parameters, the reflective unit and the corresponding receiver can be aligned by adjusting the orientation angle of the reflective unit or controlling the voltage, thereby realizing the change of the intelligent surface reflection path signal in wireless optical communication and improving system performance by actively changing the total channel gain.

[0080] Optionally, in one embodiment of this application, the intelligent surface reflection path signal of wireless optical communication is changed based on the parameters of the optical intelligent reflective surface to change the total channel gain. This includes: adjusting the orientation angle or control voltage of the reflective unit of the optical intelligent reflective surface; aligning the reflective unit with the corresponding LED of the transmitter and the receiver using a codebook lookup method or a geometric calculation method, so that the reflective unit reflects the light beam emitted by the LED to the corresponding receiver, thereby adjusting the alignment relationship between the transmitter, the optical intelligent reflective surface and the receiver in the parameters of the optical intelligent reflective surface.

[0081] Those skilled in the art should understand that the parameters of an optical intelligent reflective surface refer to the alignment relationship between the reflective surface unit and the receiver. The configuration parameters of each unit of the optical intelligent reflective surface are determined by its physical implementation method. A mirror array based on microelectromechanical system control can be realized by adjusting the orientation angle of each unit, while an intelligent reflective surface based on optical metamaterials can be realized by adjusting the control voltage of each unit of the reflective surface.

[0082] Specifically, the embodiments of this application describe the following steps for changing the smart surface reflection path signal of wireless optical communication by setting optical smart reflective surface parameters: S1: Based on the above optical intelligent reflective surface matrix To obtain the alignment relationship between the intelligent reflective surface unit and the receiver; S2: Adjust the parameters of each unit of the optical intelligent reflective surface according to the alignment relationship between the transmitter, reflective surface unit and receiver in the intelligent surface reflective optical path.

[0083] Among them, optical intelligent reflective surface matrix This indicates the alignment relationship between the smart reflective surface and the receiver. (Non-negative matrix) The number of rows represents the number of smart reflective surface units, and the number of columns represents the number of receivers. A matrix element of "1" indicates that there is a correlation between the smart reflective surface unit and the corresponding receiver, meaning that the smart surface reflection path composed of the transmitter, smart reflective surface unit, and receiver conforms to the generalized Snell's law, and the emitted light beam can be reflected by the smart surface to the designated receiver; otherwise, it indicates that there is no correlation, meaning that the smart reflective surface unit and the corresponding transceiver are not aligned.

[0084] Furthermore, embodiments of this application can align the reflective unit and the corresponding receiver using a codebook lookup method or a geometric calculation method based on optimized optical intelligent reflective surface parameters.

[0085] The configuration of reflective surface parameters based on the defined smart reflective surface matrix depends on the alignment of the reflected optical path, including the alignment of the smart reflective surface units and the transmitter, as well as the alignment with the receiver. In embodiments of this application, the reflected optical path alignment can be performed using the following alignment method: (1) Codebook lookup method: For a selected receiver and optical intelligent reflective surface unit, the projection position of the intelligent surface reflection path signal on the user plane can be changed by adjusting the configuration parameters of the optical intelligent reflective surface. In each implementation, the projection position and configuration parameters are combined as a codeword in the codebook. In a typical indoor wireless optical communication scenario, since the positions of the receiver and the optical intelligent reflective surface remain fixed for a short period of time, the codebook is generated once before each change in the receiver position, which has low complexity.

[0086] It should be noted that in the codebook lookup method, the codebook only needs to be generated once when the receiver position remains unchanged. Therefore, it has lower complexity and can meet the dynamic requirements of the system.

[0087] (2) Geometric calculation method: When the positions of the receiver and the optical intelligent reflective surface are fixed and known, the required orientation of the intelligent reflective surface unit can be calculated according to the generalized Snell's law.

[0088] Other methods for aligning reflected light paths can be provided by those skilled in the art, and no specific limitations are made here.

[0089] Therefore, embodiments of this application can use methods such as codebook lookup to align the reflected light path, thereby enabling the configuration of the parameters of the optical intelligent reflective surface and improving system performance by actively changing the total channel gain.

[0090] Combination Figures 2 to 4 As shown, the working principle of the wireless optical downlink multiple access communication method based on an optical intelligent reflective surface according to the embodiments of this application is described in detail with multiple examples.

[0091] Example 1 In multiple-input single-output wireless optical communication systems, such as Figure 2 As shown, the optical intelligent reflective surface is realized based on a mirror array controlled by a microelectromechanical system. The wireless optical downlink hybrid multiple access communication method based on the optical intelligent reflective surface in this application adopts a fusion scheme of frequency division multiple access and power domain non-orthogonal multiple access. The specific steps have been described in detail above and will not be repeated here.

[0092] Example 2 In multiple-input single-output wireless optical communication systems, such as Figure 2 As shown, the number of transmitters is 1, and the number of receivers is... When the number of intelligent reflective surface units is 0, the embodiments of this application are equivalent to traditional wireless optical downlink hybrid multiple access converged communication. When the user packet constraint is multi-user and rate constraint, the method includes the following steps: S1: Maximize the channel capacity of the communication system by optimizing user groups and determining the multiple access methods between users; When the constraints for user grouping are multi-user and rate constraints, i.e., for two users within a sub-channel, If two users use a non-orthogonal multiple access method, then an orthogonal multiple access method is used; otherwise, the following equation is solved: , Therefore, the following results can be obtained: , in, , When the channel gains of the two users within the sub-channel and the residual interference coefficient of the system satisfy the above inequality, the two users can transmit information using a power-domain non-orthogonal multiple access method. Specifically, when the serial interference cancellation process of the system is ideal, i.e., the residual interference coefficient... The following results can be obtained: , That is, when the serial interference cancellation process does not introduce residual interference, the channel gain of the two users is greater than or equal to This allows information to be transmitted using a non-orthogonal multiple access method.

[0093] Based on the above criteria, embodiments of this application can optimize user grouping using a sorting-based genetic algorithm.

[0094] like Figure 4 The diagram shown is a schematic representation of the genetic algorithm for a wireless optical downlink multiple access communication method based on an optically intelligent reflective surface, according to an embodiment of this application. Each individual in the genetic algorithm population is a pair of... A permutation of user serial numbers is performed, with adjacent users sharing a subchannel. During crossover, a segment from each of the two chromosomes is randomly selected as the offspring chromosome, and the remaining users are sequentially filled from the other chromosome to generate new individuals. During mutation, two points on the chromosome are randomly selected and swapped. During selection, the multiple access method between users is first determined according to the above criteria, then the total system channel capacity represented by each individual is calculated, and individuals with larger total system channel capacity are selected to be retained for the next generation. After multiple iterations, an optimal user ordering scheme, i.e., a user grouping scheme, is obtained, thus completing the optimization of user grouping.

[0095] S2: Transmit the signals of multiple users at the transmitting end using a hybrid multiple access method; When two users in a subchannel use a non-orthogonal multiple access scheme, the signals of the two users will be... and According to power allocation coefficient and The transmitted signal from the transmitter is obtained by performing a weighted summation. : , The transmitted signal is then mapped and modulated, and sent to the receiving end via the channel.

[0096] It is important to note that since the constraints here are multi-user and rate constraints, in order to maximize the system and rate, transmit power should be allocated to as many users as possible with strong channel gain; that is, the transmit power should be set to... That is, the signal transmitted by the transmitter is: .

[0097] When two users in a subchannel use an orthogonal multiple access scheme, the transmitter sends signals to both users in a frequency division multiple access manner. and They are orthogonal in the frequency domain, have the same transmission power, and occupy the same bandwidth, which will not be elaborated further here.

[0098] Example 3 In multiple-input single-output wireless optical communication systems, such as Figure 2 As shown, the number of transmitters is 1, and the number of receivers is... When the number of intelligent reflective surface units is 0, the embodiments of this application are equivalent to traditional visible light downlink hybrid multiple access communication. When the constraint on user packets is a single-user rate constraint, the method includes the following steps: S1: Maximize the channel capacity of the communication system by optimizing user groups and determining the multiple access methods between users; When the constraint on user groups is a single-user rate constraint, that is, for two users within a subchannel, and If two users use a non-orthogonal multiple access method, then an orthogonal multiple access method is used; otherwise, the following equation is solved: , , Therefore, the following results can be obtained: , , Because it should satisfy Therefore, we can further solve for the following results: , in, , , When the channel gains of the two users within the sub-channel and the residual interference coefficient of the system satisfy the above inequality, the two users can transmit information using a power-domain non-orthogonal multiple access method. Specifically, when the serial interference cancellation process of the system is ideal, i.e., the residual interference coefficient... The following results can be obtained: , In other words, if there is no residual interference, and the channel gains of the two users satisfy the above inequality, then information can be transmitted using a non-orthogonal multiple access method.

[0099] Based on the above criteria, embodiments of this application can optimize user grouping using a sorting-based genetic algorithm.

[0100] like Figure 4 The diagram shows a genetic algorithm for a wireless optical downlink multiple access communication method based on an optical intelligent reflective surface. Each individual in the genetic algorithm population is a pair of... A permutation of user serial numbers is performed, with adjacent users sharing a subchannel. During crossover, a segment from each of the two chromosomes is randomly selected as the offspring chromosome, and the remaining users are sequentially filled from the other chromosome to generate new individuals. During mutation, two points on the chromosome are randomly selected and swapped. During selection, the multiple access method between users is first determined according to the above criteria, then the total system channel capacity represented by each individual is calculated, and individuals with larger total system channel capacity are selected to be retained for the next generation. After multiple iterations, an optimal user ordering scheme, i.e., a user grouping scheme, is obtained, thus completing the optimization of user grouping.

[0101] S2: Transmit the signals of multiple users at the transmitting end using a hybrid multiple access method; When two users in a subchannel use a non-orthogonal multiple access scheme, the signals of the two users will be... and According to power allocation coefficient and The transmitted signal from the transmitter is obtained by performing a weighted summation. : , The transmitted signal is then mapped and modulated, and sent to the receiving end via the channel.

[0102] It is important to note that since the constraint here is a single-user rate constraint, in order to maximize the system and rate, the transmit power allocated to users with weaker channel gain should be as small as possible, i.e., satisfying the following: Thus, we can obtain Therefore, the signal transmitted by the transmitter is: .

[0103] When two users in a subchannel use an orthogonal multiple access scheme, the transmitter sends signals to both users in a frequency division multiple access manner. and They are orthogonal in the frequency domain, have the same transmission power, and occupy the same bandwidth, which will not be elaborated further here.

[0104] The wireless optical downlink multiple access communication method based on an optical intelligent reflective surface proposed in this application optimizes user groups and determines the multiple access mode among multiple users based on at least one optimized user group. It optimizes the optical intelligent reflective surface parameters and the transmitter power allocation coefficient. By combining the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access mode, a corresponding multi-user signal transmission strategy is generated. Utilizing this strategy for signal transmission effectively reduces the mean square error and bit error rate of the wireless optical communication system, increases the system capacity, enhances multi-user access capability, and reduces the impact of obstacles on wireless optical communication. This effectively improves the spatial multiplexing gain, increases the channel capacity, and enhances multi-user access capability of the wireless optical communication system. Therefore, it solves the technical problem in related technologies where wireless optical communication systems are easily interrupted when obstructed by obstacles.

[0105] Next, referring to the accompanying drawings, a wireless optical downlink multiple access communication device based on an optically intelligent reflective surface, according to an embodiment of this application, is described.

[0106] Figure 5This is a block diagram of a wireless optical downlink multiple access communication device based on an optically intelligent reflective surface according to an embodiment of this application.

[0107] like Figure 5 As shown, the wireless optical downlink multiple access communication device 10 based on an optical intelligent reflective surface includes: a packet module 100, an acquisition module 200, and a communication module 300.

[0108] Specifically, the grouping module 100 is used to optimize at least one user group using preset optimization constraints, and to determine the multiple access method among multiple users based on the optimized at least one user group.

[0109] The acquisition module 200 is used to acquire the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection.

[0110] The communication module 300 is used to combine the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient and the multiple access method to generate a corresponding multi-user signal transmission strategy, so as to use the multi-user signal transmission strategy for signal transmission.

[0111] Optionally, in one embodiment of this application, the grouping module 100 includes: a calculation unit, a grouping unit, and a matching unit.

[0112] The computing unit is used to calculate the line-of-sight path channel gain and the smart surface reflection path channel gain for each user, based on the channel state information of the line-of-sight path and the smart surface reflection path, combined with the position information of the transmitter, the optical smart reflective surface and the receiver.

[0113] The grouping unit is used to optimize user grouping based on the line-of-sight path channel gain and preset targets for each user, combined with preset optimization constraints and using preset optimization methods.

[0114] The matching unit is used to match the best multiple access method based on the optimized user group.

[0115] Optionally, in one embodiment of this application, the optimal multiple access method is to use a non-orthogonal multiple access method or an orthogonal multiple access method for multiple user signals in the same group, and an orthogonal multiple access method for multiple user signals in different groups; wherein, the non-orthogonal multiple access method includes at least one of power domain non-orthogonal multiple access method, code domain non-orthogonal multiple access method, and sparse coded multiple access method; the orthogonal multiple access method includes at least one of time domain orthogonal access method, frequency domain orthogonal access method, and orthogonal frequency division multiple access method.

[0116] Optionally, in one embodiment of this application, the preset optimization constraints include at least one of the following: non-negative real number constraints of optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user sum rate constraints, and single-user rate constraints.

[0117] Optionally, in one embodiment of this application, the preset objective includes at least one of minimizing the bit error rate of the wireless optical communication system, maximizing the channel capacity, and maximizing the minimum user rate.

[0118] Optionally, in one embodiment of this application, the acquisition module 200 includes an optimization unit and a first adjustment unit.

[0119] The optimization unit is used to optimize the parameters of the optical intelligent reflective surface based on the channel state information of the line-of-sight path and the intelligent surface reflection path, combined with the position information of the transmitter, the optical intelligent reflective surface and the receiver, to obtain the optimal optical intelligent reflective surface parameters.

[0120] The first adjustment unit is used to adjust the transmit power allocation coefficient of each user at the transmitter end according to the total channel gain of each user, so as to obtain the optimal transmit power allocation coefficient at the transmitter end.

[0121] Optionally, in one embodiment of this application, the wireless optical downlink multiple access communication device 10 based on an optical smart reflective surface further includes: a first adjustment module and a second adjustment module.

[0122] The adjustment module is used to adjust the parameters of the optical intelligent reflective surface based on the user's change command, and to change the intelligent surface reflection path signal of the wireless optical communication based on the optical intelligent reflective surface parameters, so as to change the total channel gain.

[0123] Optionally, in one embodiment of this application, the adjustment module includes a second adjustment unit and a third adjustment unit.

[0124] The second adjustment unit is used to adjust the orientation angle of the reflective unit of the optical intelligent reflective surface or to control the voltage.

[0125] The third adjustment unit is used to align the reflective unit with the corresponding LED of the transmitter and the receiver using a codebook lookup method or a geometric calculation method, so that the reflective unit reflects the light beam emitted by the LED to the corresponding receiver, thereby adjusting the alignment relationship between the transmitter, the optical intelligent reflective surface and the receiver in the optical intelligent reflective surface parameters.

[0126] It should be noted that the foregoing explanation of the embodiment of the wireless optical downlink multiple access communication method based on an optical intelligent reflective surface also applies to the wireless optical downlink multiple access communication device based on an optical intelligent reflective surface in this embodiment, and will not be repeated here.

[0127] According to the wireless optical downlink multiple access communication device based on an optical intelligent reflective surface proposed in this application, user group optimization is performed, and the multiple access mode among multiple users is determined based on at least one optimized user group. The optical intelligent reflective surface parameters and the transmitter power allocation coefficient are optimized. By combining the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access mode, a corresponding multi-user signal transmission strategy is generated. Using this strategy for signal transmission can effectively reduce the mean square error and bit error rate of the wireless optical communication system, increase the system capacity, improve multi-user access capability, and reduce the impact of obstacles on wireless optical communication. This effectively improves the spatial multiplexing gain, increases the channel capacity, and enhances multi-user access capability of the wireless optical communication system. Therefore, it solves the technical problem in related technologies where wireless optical communication systems are easily interrupted when obstructed by obstacles.

[0128] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0129] When the processor 602 executes the program, it implements the wireless optical downlink multiple access communication method based on an optical intelligent reflective surface provided in the above embodiments.

[0130] Furthermore, electronic devices also include: Communication interface 603 is used for communication between memory 601 and processor 602.

[0131] The memory 601 is used to store computer programs that can run on the processor 602.

[0132] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0133] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0134] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0135] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0136] This embodiment also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described wireless optical downlink multiple access communication method based on an optical intelligent reflective surface.

[0137] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0138] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0139] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0140] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0141] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0142] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0143] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0144] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A wireless optical downlink multiple access communication method based on an optical intelligent reflective surface, characterized in that, Includes the following steps: Optimize at least one user group using preset optimization constraints, and determine the multiple access method among multiple users based on the optimized at least one user group; Obtain the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection; By combining the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access method, a corresponding multi-user signal transmission strategy is generated to utilize the multi-user signal transmission strategy for signal transmission.

2. The method according to claim 1, characterized in that, The step of optimizing user groups using optimization constraints and determining the multiple access method among multiple users includes: Based on the channel state information of the line-of-sight path and the smart surface reflection path, and combined with the position information of the transmitter, the optical smart reflective surface and the receiver, the line-of-sight path channel gain and the smart surface reflection path channel gain for each user are calculated. Based on the line-of-sight path channel gain and preset target for each user, and combined with the preset optimization constraints, the user grouping is optimized using a preset optimization method. The optimal multi-access method is matched based on the optimized user grouping.

3. The method according to claim 2, characterized in that, The optimal multiple access method is to use a non-orthogonal multiple access method or an orthogonal multiple access method for multiple user signals in the same group, and an orthogonal multiple access method for multiple user signals in different groups; wherein, the non-orthogonal multiple access method includes at least one of power domain non-orthogonal multiple access method, code domain non-orthogonal multiple access method, and sparse coded multiple access method; the orthogonal multiple access method includes at least one of time domain orthogonal access method, frequency domain orthogonal access method, and orthogonal frequency division multiple access method.

4. The method according to claim 2, characterized in that, The preset optimization constraints include at least one of the following: non-negative real number constraints for optical signals, total transmit power constraints, non-orthogonal multiple access power allocation coefficient constraints, user service quality constraints, multi-user rate constraints, and single-user rate constraints.

5. The method according to claim 2, characterized in that, The preset objectives include at least one of the following: minimizing the bit error rate of the wireless optical communication system, maximizing the channel capacity, and maximizing the minimum user rate.

6. The method according to claim 2, characterized in that, The process of obtaining the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection includes: Based on the channel state information of the line-of-sight path and the smart surface reflection path, and combined with the position information of the transmitter, the optical smart reflective surface and the receiver, the parameters of the optical smart reflective surface are optimized to obtain the optimal optical smart reflective surface parameters. Based on the total channel gain of each user, the transmit power allocation coefficient of each user at the transmitter is adjusted to obtain the optimal transmit power allocation coefficient at the transmitter.

7. The method according to claim 6, characterized in that, Also includes: The parameters of the optical intelligent reflective surface are adjusted based on the user's change instructions; Based on the optical intelligent reflective surface parameters, the intelligent surface reflection path signal of wireless optical communication is changed to alter the total channel gain.

8. The method according to claim 7, characterized in that, The method of changing the smart surface reflection path signal of wireless optical communication based on the optical smart reflective surface parameters to change the total channel gain includes: Adjusting the orientation angle of the reflective unit of the optical intelligent reflective surface or controlling the voltage; The reflective unit is aligned with the corresponding LED of the transmitter and the receiver using a codebook lookup method or a geometric calculation method, so that the reflective unit reflects the light beam emitted by the LED to the corresponding receiver, thereby adjusting the alignment relationship between the transmitter, the optical intelligent reflective surface and the receiver in the optical intelligent reflective surface parameters.

9. A wireless optical downlink multiple access communication device based on an optical intelligent reflective surface, characterized in that, include: The grouping module is used to optimize at least one user group using preset optimization constraints, and to determine the multiple access method among multiple users based on the optimized at least one user group. The acquisition module is used to acquire the optimal optical intelligent reflective surface parameters and the optimal transmitter power allocation coefficient for intelligent surface reflection. The communication module is used to combine the optimal optical intelligent reflective surface parameters, the optimal transmitter power allocation coefficient, and the multiple access method to generate a corresponding multi-user signal transmission strategy, so as to use the multi-user signal transmission strategy for signal transmission.

10. An electronic device, characterized in that, include: The memory, the processor, and the computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the wireless optical downlink multiple access communication method based on an optical smart reflective surface as described in any one of claims 1-8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the wireless optical downlink multiple access communication method based on an optical smart reflective surface as described in any one of claims 1-8.

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