Method and device for reducing peak-to-average power ratio of miniature LED optical communication system

Abstract

The invention discloses a method and device for reducing the peak-to-average power ratio of a miniature LED optical communication system, and the method comprises the steps: carrying out the precoding of the modulation data of a first user and the modulation data of a second user at a transmitting end of a VLC system through a precoding matrix, respectively obtaining a pre-coding output signal of the first user and a pre-coding output signal of the second user; performing combined calculation on the precoding output signal of the first user and the precoding output signal of the second user based on the power distribution factor and the total power of the precoding output signal of the first user and the precoding output signal of the second user to obtain a precoding frequency domain signal; expanding the pre-coded frequency domain signal into an expanded frequency domain signal with Hermitian symmetry, and performing fast Fourier inverse transform on the expanded frequency domain signal to obtain a pre-coded time domain signal; and mu-law compression processing is carried out on the pre-coding time domain signal to obtain a compressed signal, and a peak-to-average power ratio is calculated according to the compressed signal. According to the invention, the PAPR can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of visible light communication, and in particular to a method and device for reducing the peak-to-average power ratio of a micro LED optical communication system. Background Art

[0002] With the increase in data communication needs, traditional RF (radio frequency) communication technology has been unable to meet the needs of high-speed and high-capacity transmission. Visible light communication (VLC), as an emerging data transmission method, uses LED light-emitting devices to transmit data. Due to its rich spectrum resources, low cost and freedom from electromagnetic interference, it has become a strong candidate to solve the limitations of traditional communications. Orthogonal frequency division multiplexing (OFDM) has become the mainstream modulation technology in VLC systems due to its high data transmission rate and ability to resist multipath interference. However, OFDM technology, which is widely used in VLC systems, will cause nonlinear distortion of LEDs due to its high PAPR problem, which in turn affects the efficiency and signal quality of the entire system.

[0003] Currently, a variety of technologies have been proposed to reduce the PAPR in OFDM systems, such as peak clipping and filtering, selective mapping (SLM), partial transmission sequence (PTS), etc. However, these technologies will increase the complexity of the system or sacrifice a certain degree of data transmission efficiency. In the VLC environment, due to the inherent characteristics of its chip structure and materials, LEDs exhibit significant nonlinear characteristics under large signal drive, especially under high power drive, this nonlinearity is more obvious. Peak clipping technology reduces PAPR by directly cutting high peak signals, but in VLC systems with micro LEDs as light sources, this method will further aggravate the nonlinear distortion of optical signals because the high-frequency components generated after peak clipping will be amplified by the nonlinearity of micro LEDs; selective mapping (SLM) and partial transmission sequence (PTS) transform the input signal multiple times to select the signal with the lowest PAPR for transmission. Although they can reduce PAPR, their implementation requires the addition of complex signal processing circuits at the receiving and transmitting ends, resulting in increased system cost and power consumption.

[0004] The transmitter in wireless communication needs to handle long-distance transmission, so the efficiency of the power amplifier is particularly important. Too high PAPR will cause the output power of the power amplifier to decrease, thus affecting the communication quality and coverage. To reduce PAPR, the signal is pre-distorted at the transmitter. In the field of VLC, since LED-VLC is mainly used for short-distance communication, PAPR reduction technology directly affects the working stability of LEDs and also affects the efficiency of the communication system. Therefore, the modulation amplitude of high peak signals is limited to make the LED work within a reasonable linear range.

[0005] In addition, with the application of multiple-input multiple-output (MIMO) technology in VLC systems, multiple signals can be transmitted simultaneously to increase the transmission rate and channel capacity, which further aggravates the PAPR problem. In MIMO-OFDM systems, the superposition of multiple signals may result in higher peak power, thus increasing the severity of the PAPR problem.

[0006] Existing PAPR reduction technologies face the dual challenges of complexity and processing efficiency when dealing with complex MIMO-OFDM systems. In actual deployment, these technologies often require special hardware design, such as adding a linearization processing module, which not only increases costs but also reduces the processing efficiency of the system.

[0007] Micro-LED-based VLC systems are seen as an effective way to improve the performance of VLC systems because of their faster modulation speeds. However, compared to traditional LED light sources, micro-LEDs have a higher emission bandwidth, which enables them to support higher data transmission rates and be suitable for higher-order modulation schemes (such as QAM-OFDM). The high emission bandwidth feature enables micro-LEDs to transmit signals with a wider frequency range, which makes the high-frequency components in the signal more susceptible to the nonlinear effects of LEDs. When the PAPR of the input signal is high, the instantaneous peak power of the signal may exceed the linear operating range of the micro-LED, resulting in signal distortion, which is particularly significant in the high-frequency components. This places higher demands on existing PAPR reduction technologies. Summary of the invention

[0008] The purpose of this application is to propose a method and device for reducing the peak-to-average power ratio of a micro LED optical communication system in response to the above-mentioned technical problems.

[0009] In a first aspect, the present invention provides a method for reducing a peak-to-average power ratio of a micro LED optical communication system, comprising the following steps:

[0010] Acquire, at a transmitting end of the VLC system, modulated data of a first user and modulated data of a second user, and precode the modulated data of the first user and the modulated data of the second user respectively through a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively;

[0011] Combining and calculating the precoded output signal of the first user and the precoded output signal of the second user based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user to obtain a precoded frequency domain signal;

[0012] Expand the precoded frequency-domain signal into an extended frequency-domain signal with Hermitian symmetry, and perform an inverse fast Fourier transform on the extended frequency-domain signal to obtain a precoded time-domain signal;

[0013] Perform μ-law companding on the precoded time-domain signal to obtain a compressed signal, and calculate the peak-to-average power ratio based on the compressed signal.

[0014] Preferably, the order of the precoding matrix is R*N, expressed as:

[0015]

[0016] where PM represents the precoding matrix, and the elements of the precoding matrix are defined as:

[0017]

[0018] where N is the number of subcarriers of the baseband modulated data, Np is the null carrier, 0 < N p < N, R = N + Np, m ∈ {0, 1, 2,..., R - 1}, and k ∈ {0, 1, 2,..., N - 1}, j is the imaginary unit, P m,k represents the element in the (m - 1)-th row and (k - 1)-th column of the precoding matrix, P m,0 represents the element in the (m - 1)-th row and the 1st column of the precoding matrix, expressed as:

[0019]

[0020] Preferably, perform precoding on the modulated data of the first user and the modulated data of the second user respectively through the precoding matrix to obtain the precoded output signal of the first user and the precoded output signal of the second user respectively, specifically including:

[0021] Y1 = PM * X1;

[0022] Y2 = PM * X2;

[0023] where PM represents the precoding matrix, X1 represents the modulated data of the first user, X2 represents the modulated data of the second user, Y1 represents the precoded output signal of the first user, and Y2 represents the precoded output signal of the second user.

[0024] Preferably, the precoded frequency-domain signal is expressed as:

[0025]

[0026] where S p is the precoded frequency-domain signal, α is the power allocation factor, Y1 represents the precoded output signal of the first user, Y2 represents the precoded output signal of the second user, P totis the total power of Y1 and Y2, S p consists of N subcarriers, expressed as:

[0027] S p = [S0, S1, S2, …, S N-1 T ;

[0028] wherein, S N-1 represents the Nth subcarrier in the precoded frequency-domain signal;

[0029] The extended signal is expressed as: S HS = [S0, …, S N , …, S 2N-i , …, S 2N-1 T ;

[0030] wherein, S i represents the (i + 1)th subcarrier in the extended signal, S 2N-K is the complex conjugate of S i .

[0031] Preferably, the precoded time-domain signal is expressed as:

[0032]

[0033] wherein, Y(n) represents the precoded time-domain signal, S i represents the (i + 1)th subcarrier in the extended signal, N is the number of subcarriers of the baseband modulated data, Np is the null carrier, 0 < N p < N, R = N + Np, n represents the discrete-time sampling point of the precoded time-domain signal.

[0034] Preferably, the compressed signal is expressed as:

[0035]

[0036] wherein, S proposed (n) represents the compressed signal, μ represents the compression control factor, the range is 0 - 255, v represents the maximum amplitude, sgn(Y(n)) represents the sign function of Y(n);

[0037] The peak-to-average power ratio is expressed as:

[0038]

[0039] wherein, |S proposed (n) max | 2 represents the peak power of the compressed signal, E|S proposed (n)| 2 ​​Indicates the average power of the peak signal.

[0040] In a second aspect, the present invention provides a device for reducing the peak-to-average power ratio of a micro LED optical communication system, comprising:

[0041] A precoding module is configured to obtain the modulation data of the first user and the modulation data of the second user at the transmitting end of the VLC system, and precode the modulation data of the first user and the modulation data of the second user respectively through a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively;

[0042] a combined calculation module, configured to perform combined calculation on the precoded output signal of the first user and the precoded output signal of the second user based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user to obtain a precoded frequency domain signal;

[0043] A transform module is configured to expand the precoded frequency domain signal into an extended frequency domain signal with Hermitian symmetry, and perform an inverse fast Fourier transform on the extended frequency domain signal to obtain a precoded time domain signal;

[0044] The compression module is configured to perform μ-law compression processing on the precoded time domain signal to obtain a compressed signal, and calculate the peak-to-average power ratio based on the compressed signal.

[0045] In a third aspect, the present invention provides an electronic device comprising one or more processors; a storage device for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method described in any implementation manner in the first aspect.

[0046] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any implementation manner in the first aspect.

[0047] In a fifth aspect, the present invention provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method described in any implementation manner in the first aspect.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The method for reducing the peak-to-average power ratio of a micro-LED optical communication system proposed in the present invention effectively reduces the peak-to-average power ratio (PAPR) of a micro-LED-based VLC system by combining the use of a precoding matrix and u-law compression and expansion. By optimizing the pre-coding and dynamic range compression of the signal, not only the PAPR is reduced, but also the signal integrity and transmission efficiency are maintained.

[0050] (2) The method of reducing the peak-to-average power ratio of the micro LED optical communication system proposed in the present invention reduces the nonlinear distortion of the LED by reducing the PAPR, thereby improving the efficiency of the light source and the overall energy efficiency of the system. This is particularly important for VLC systems that use LEDs as light sources, because the performance of LEDs directly affects the communication quality and energy consumption. Since the technical solution proposed in the present invention can be implemented without relying on additional hardware support, it also greatly reduces the cost of system deployment and maintenance.

[0051] (3) The method for reducing the peak-to-average power ratio of the micro LED optical communication system proposed in the present invention improves the signal processing efficiency and fault tolerance of the system by reducing PAPR, making the system more stable. The method is particularly suitable for deployment in indoor environments with dense users and high data demand, making the present invention have high application value in business and technology, and is expected to be widely used in the field of high-speed VLC communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 A schematic flow chart of a method for reducing a peak-to-average power ratio of a micro LED optical communication system according to an embodiment of the present application;

[0054] Figure 2 A system architecture diagram of a method for reducing a peak-to-average power ratio of a micro LED optical communication system according to an embodiment of the present application;

[0055] Figure 3 A schematic diagram of a flow chart of a transmitting end of a method for reducing a peak-to-average power ratio of a micro LED optical communication system according to an embodiment of the present application;

[0056] Figure 4 A flowchart of a receiving end of a method for reducing a peak-to-average power ratio of a micro LED optical communication system according to an embodiment of the present application;

[0057] Figure 5Schematic diagram of the apparatus for reducing the peak-to-average power ratio of the micro-LED optical communication system according to the embodiment of the present application;

[0058] Figure 6 Schematic diagram of the hardware structure of the electronic device provided by the embodiment of the present invention. Detailed implementation manners

[0059] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Figure 1 A method for reducing the peak-to-average power ratio of a micro-LED optical communication system provided by the embodiment of the present application is shown, including the following steps:

[0061] S1. Obtain the modulation data of the first user and the modulation data of the second user at the transmitting end of the VLC system, and perform precoding on the modulation data of the first user and the modulation data of the second user respectively through a precoding matrix to obtain the precoded output signal of the first user and the precoded output signal of the second user respectively.

[0062] In a specific embodiment, the order of the precoding matrix is R*N, expressed as:

[0063]

[0064] Wherein, PM represents the precoding matrix, and the elements of the precoding matrix are defined as:

[0065]

[0066] Wherein, N is the number of subcarriers of the baseband modulation data, Np is the null carrier, 0 < N p < N, R = N + Np, m ∈ {0, 1, 2,..., R - 1}, and k ∈ {0, 1, 2,..., N - 1}, j is an imaginary number, P m,k represents the element in the (m - 1)-th row and the (k - 1)-th column of the precoding matrix, and P m,0 represents the element in the (m - 1)-th row and the 1st column of the precoding matrix, expressed as:

[0067]

[0068] In a specific embodiment, the modulation data of the first user and the modulation data of the second user are precoded by a precoding matrix respectively to obtain the precoded output signal of the first user and the precoded output signal of the second user, which specifically includes:

[0069] Y1 = PM * X1;

[0070] Y2 = PM * X2;

[0071] wherein, PM represents the precoding matrix, X1 represents the modulation data of the first user, X2 represents the modulation data of the second user, Y1 represents the precoded output signal of the first user, and Y2 represents the precoded output signal of the second user.

[0072] Specifically, the embodiment of the present application is used for a high-speed VLC system of micro LEDs, and specifically combines precoding and companding techniques. The system architecture is as Figure 2 shown, including a transmitting end and a receiving end. As Figure 3 shown, at the transmitting end, it is assumed that X1 and X2 respectively represent the modulation data of the first user (U1) and the second user (U2). The modulation data of the first user and the second user are respectively preprocessed in the frequency domain by a precoding matrix PM, so as to obtain the precoded output signals of the first user and the second user. In the precoding matrix PM, Np is the null carrier used to reduce adjacent channel interference, and the value of m is 0 ≤ m < N p , corresponding to the null carrier part, the weight is determined by a sine function; the value of m is N p ≤ m < N p +N, corresponding to the effective data subcarrier part; the value of m is N p +N ≤ m < R - 1, corresponding to the high-frequency part of the carrier, and a cosine function is used to determine. Through the linear transformation of precoding, the peak power of the signal can be effectively reduced.

[0073] S2. Based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user, the precoded output signal of the first user and the precoded output signal of the second user are combined and calculated to obtain the precoded frequency-domain signal.

[0074] In a specific embodiment, the precoded frequency-domain signal is expressed as:

[0075]

[0076] wherein, S p is the precoded frequency-domain signal, α is the power allocation factor, Y1 represents the precoded output signal of the first user, Y2 represents the precoded output signal of the second user, P tot is the total power of Y1 and Y2, and S p is composed of N subcarriers and is expressed as:

[0077] S p = [S0, S1, S2, …, S N-1 T ;

[0078] Among them, S N-1 represents the Nth subcarrier in the precoded frequency-domain signal;

[0079] The extended signal is expressed as: S HS = [S0, …, S N , …, S 2N-i , …, S 2N-1 T ;

[0080] Among them, S i represents the (i + 1)th subcarrier in the extended signal, S 2N-K is the complex conjugate of S i .

[0081] Specifically, considering the power allocation of different user signals, the precoded output signals of the first user and the second user are combined and calculated. During the calculation process, it is necessary to ensure that the transmission power meets the system limit, so the total power of Y1 and Y2 is used.

[0082] S3 is used to expand the precoded frequency-domain signal into an extended frequency-domain signal with Hermitian symmetry, and the inverse fast Fourier transform is performed on the extended frequency-domain signal to obtain the precoded time-domain signal.

[0083] In a specific embodiment, the precoded time-domain signal is expressed as:

[0084]

[0085] Among them, Y(n) represents the precoded time-domain signal, S i represents the (i + 1)th subcarrier in the extended signal, N is the number of subcarriers of the baseband modulated data, Np is the null carrier, 0 < N p < N, R = N + Np, and n represents the discrete time sampling points of the precoded time-domain signal.

[0086] Specifically, to meet the requirement of outputting a real-valued time-domain signal in the visible light communication of micro-LEDs, the precoded frequency-domain signal S p is expanded into an extended signal S HS with Hermitian symmetry, and the extended signal S HS generated by the Hermitian symmetry transformation (HS) is the precoded frequency-domain signal S p ​​In order to adapt to the unipolar optical signal transmission of micro-LEDs, DC bias (DCO-bias) and clipping need to be added. Therefore, the extended signal is subjected to an inverse fast Fourier transform (IFFT) to generate a real-valued precoded time domain signal Y(n), and a DC bias is applied to ensure that the signal is suitable for micro-LED light source transmission.

[0087] S4, performing μ-law compression processing on the precoded time domain signal to obtain a compressed signal, and calculating the peak-to-average power ratio according to the compressed signal.

[0088] In a specific embodiment, the compressed signal is represented as:

[0089]

[0090] Among them, S proposed (n) represents the compressed signal, μ represents the compression control factor, ranging from 0 to 255, v represents the maximum amplitude, and sgn(Y(n)) represents the sign function of Y(n);

[0091] The peak-to-average power ratio is expressed as:

[0092]

[0093] Among them, |S proposed (n) max | 2 Indicates the peak power of the compressed signal, E|S proposed (n)| 2 Indicates the average power of the peak signal.

[0094] Specifically, the precoded time domain signal Y(n) is subjected to μ-law compression processing to obtain a compressed signal. The PAPR (peak-to-average power ratio) of the time domain signal is related to the ratio of the sealed power to the average power of the compressed signal. μ-law compression processing is performed on the precoded time domain signal to further suppress the instantaneous power peak. This nonlinear compression operation can effectively reduce the PAPR while retaining the phase information of the signal. The peak power of the signal is reduced by signal precoding and amplitude compression. The compressed signal is transmitted through a micro LED light source to achieve wireless transmission of the optical signal. During the transmission process, the high-frequency components of the signal will be appropriately suppressed to reduce the nonlinear distortion of the micro LED.

[0095] At the receiving end of the NOMA network, the base station (BS) receives the signal sent by each user, and the received signal is expressed as:

[0096]

[0097] Where L represents the total number of users, h(g) is the channel coefficient of the g-th user, and P totrepresents the total power used, ε is a Gaussian white noise with a mean of 0 and a standard deviation of σ, expressed as ε~N(0,δ).

[0098] like Figure 4 As shown, the receiving end receives the optical signal transmitted from the transmitting end through a photodetector, converts the optical signal into an electrical signal, and then performs μ-law inverse compression to restore the dynamic range, removes the cyclic prefix to eliminate the empty carrier part, and the decompression formula is as follows:

[0099]

[0100] Among them, S recv (n) is the received electrical signal, and μ is the compression control factor consistent with the transmitting end.

[0101] The time domain signal is then converted into a frequency domain signal through a fast Fourier transform (FFT), and the frequency domain signal is de-precoded to restore the original modulated signal. -1 The signal is decoded to recover the independent signal of each user. This decoding process ensures the integrity of the user signal and reduces the impact of multi-user interference.

[0102] For multi-user scenarios, the receiver uses serial interference cancellation (SIC) to gradually decode the signal of each user, and finally restores the data through demodulation, thereby achieving separation and restoration of multi-user signals.

[0103] The total complexity of the method for reducing the peak-to-average power ratio of the micro-LED optical communication system proposed in the embodiment of the present application is compared with other methods for reducing the peak-to-average power ratio. The comparison results are shown in Table 1, where U: the number of candidate signals, the optimization parameter in SLM; V: the number of phase rotation combinations, the optimization parameter in PTS; N: the number of subcarriers, which affects the complexity of all methods; O(x): complexity representation. It can be seen that the method for reducing the peak-to-average power ratio of the micro-LED optical communication system proposed in the embodiment of the present application can effectively reduce the complexity of the system.

[0104] Table 1

[0105]

[0106] Further references Figure 5 As an implementation of the methods shown in the above figures, the present application provides an embodiment of a device for reducing the peak-to-average power ratio of a micro-LED optical communication system. Figure 1 Corresponding to the method embodiment shown, the device can be specifically applied to various electronic devices.

[0107] The embodiment of the present application provides a device for reducing the peak-to-average power ratio of a micro LED optical communication system, including:

[0108] A precoding module 1 is configured to obtain modulated data of a first user and modulated data of a second user at a transmitting end of the VLC system, and precode the modulated data of the first user and the modulated data of the second user respectively through a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively;

[0109] A combined calculation module 2 is configured to perform combined calculation on the precoded output signal of the first user and the precoded output signal of the second user based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user to obtain a precoded frequency domain signal;

[0110] A transformation module 3 is configured to expand the precoded frequency domain signal into an extended frequency domain signal with Hermitian symmetry, and perform an inverse fast Fourier transform on the extended frequency domain signal to obtain a precoded time domain signal;

[0111] The compression module 4 is configured to perform μ-law compression processing on the precoded time domain signal to obtain a compressed signal, and calculate the peak-to-average power ratio based on the compressed signal.

[0112] Figure 6 Schematic diagram of the hardware structure of the electronic device provided by the embodiment of the present invention. Figure 6 As shown, the electronic device of this embodiment includes: a processor 601 and a memory 602; wherein the memory 602 is used to store computer-executable instructions; the processor 601 is used to execute the computer-executable instructions stored in the memory to implement the various steps performed by the electronic device in the above embodiment. For details, please refer to the relevant description in the above method embodiment.

[0113] Optionally, the memory 602 may be independent or integrated with the processor 601 .

[0114] When the memory 602 is independently provided, the electronic device further includes a bus 603 for connecting the memory 602 and the processor 601 .

[0115] The embodiment of the present invention further provides a computer storage medium, in which computer execution instructions are stored. When the processor 601 executes the computer execution instructions, the above method is implemented.

[0116] The embodiment of the present invention further provides a computer program product, including a computer program. When the computer program is executed by the processor 601, the above method is implemented.

[0117] In the embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules is only a logical function division, and there may be other division methods in actual implementation, such as multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0118] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to implement the solution of this embodiment.

[0119] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each module may exist physically separately, or two or more modules may be integrated into one unit. The unit formed by the above modules may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0120] The above-mentioned integrated module implemented in the form of a software function module can be stored in a computer-readable storage medium. The above-mentioned software function module is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor 601 to perform some steps of the methods of various embodiments of the present application.

[0121] It should be understood that the processor 601 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or the processor 601 may be any conventional processor 601, etc. The steps of the method disclosed in the invention may be directly embodied in the execution of the hardware processor 601, or may be executed by a combination of hardware and software modules in the processor 601.

[0122] The memory 602 may include a high-speed RAM memory, and may also include a non-volatile storage NVM, such as at least one disk memory, and may also be a USB flash drive, a mobile hard disk, a read-only memory, a magnetic disk, or an optical disk.

[0123] The bus 603 may be an Industry Standard Architecture (ISA), a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus 603 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus 603 in the drawings of the present application is not limited to only one bus 603 or one type of bus 603.

[0124] The above storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0125] An exemplary storage medium is coupled to the processor 601, so that the processor 601 can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor 601. The processor 601 and the storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor 601 and the storage medium can also exist as discrete components in an electronic device or a main control device.

[0126] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0127] 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing the peak-to-average power ratio of a micro LED optical communication system, characterized in that: The following steps are involved: Acquire, at a transmitting end of the VLC system, modulated data of a first user and modulated data of a second user, and precode the modulated data of the first user and the modulated data of the second user respectively through a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively; Combining and calculating the precoded output signal of the first user and the precoded output signal of the second user based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user to obtain a precoded frequency domain signal; Expanding the precoded frequency domain signal into an extended frequency domain signal with Hermitian symmetry, and performing an inverse fast Fourier transform on the extended frequency domain signal to obtain a precoded time domain signal; The precoded time domain signal is subjected to μ-law compression processing to obtain a compressed signal, and a peak-to-average power ratio is calculated based on the compressed signal.

2. The method for reducing the peak-to-average power ratio of a micro LED optical communication system according to claim 1, characterized in that: The order of the precoding matrix is ​​R*N, which is expressed as: Wherein, PM represents a precoding matrix, and the elements of the precoding matrix are defined as: where N is the number of subcarriers of the baseband modulated data, Np is the null carrier, 0 < N p <N, R = N + Np, m ∈ {0, 1, 2, …, R - 1}, and k ∈ {0, 1, 2, … N - 1}, j is the imaginary number, P m,k represents the element in the (m - 1)-th row and (k - 1)-th column of the precoding matrix, P m,0 represents the element in the (m - 1)-th row and the 1st column of the precoding matrix, expressed as:

3. The method for reducing the peak-to-average power ratio of a micro LED optical communication system according to claim 1, characterized in that: Precoding the modulated data of the first user and the modulated data of the second user respectively by using a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively, specifically comprising: Y1=PM*X1; Y2=PM*X2; Among them, PM represents the precoding matrix, X1 represents the modulation data of the first user, X2 represents the modulation data of the second user, Y1 represents the precoding output signal of the first user, and Y2 represents the precoding output signal of the second user.

4. The method for reducing the peak-to-average power ratio of a micro LED optical communication system according to claim 1, characterized in that: The precoded frequency domain signal is expressed as: Among them, S p is the precoded frequency domain signal, α is the power allocation factor, Y1 represents the precoded output signal of the first user, Y2 represents the precoded output signal of the second user, P tot is the total power of Y1 and Y2, S p It consists of N subcarriers, expressed as: S p =[S0,S1,S2,…,S N-1 ] T ; Among them, S N-1 represents the Nth subcarrier in the precoded frequency domain signal; The extended signal is represented by: S HS =[S0,…,S N ,…,S 2N-i ,…,S 2N-1 ] T ; Among them, S i represents the i+1th subcarrier in the extended signal, S 2N-K For S i The complex conjugate of .

5. The method for reducing the peak-to-average power ratio of a micro LED optical communication system according to claim 1, characterized in that: The precoded time domain signal is expressed as: Among them, Y(n) represents the precoded time-domain signal, and S i represents the (i + 1)-th subcarrier in the extended signal, N is the number of subcarriers of the baseband modulated data, Np is the null carrier, 0 < N p < N, R = N + Np, and n represents the discrete-time sampling point of the precoded time-domain signal.

6. The method for reducing the peak-to-average power ratio of a micro LED optical communication system according to claim 1, characterized in that: The compressed signal is expressed as: Among them, S proposed (n) represents the compressed signal, μ represents the compression control factor, ranging from 0 to 255, v represents the maximum amplitude, and sgn(Y(n)) represents the sign function of Y(n); The peak-to-average power ratio is expressed as: Among them, |S proposed (n) max | 2 represents the peak power of the compressed signal, E|S proposed (n)| 2 represents the average power of the peak signal.

7. A device for reducing the peak-to-average power ratio of a micro LED optical communication system, characterized in that: include: A precoding module is configured to obtain modulated data of a first user and modulated data of a second user at a transmitting end of the VLC system, and precode the modulated data of the first user and the modulated data of the second user respectively through a precoding matrix to obtain a precoded output signal of the first user and a precoded output signal of the second user respectively; a combined calculation module, configured to perform combined calculation on the precoded output signal of the first user and the precoded output signal of the second user based on the power allocation factor and the total power of the precoded output signal of the first user and the precoded output signal of the second user, so as to obtain a precoded frequency domain signal; a transform module configured to expand the precoded frequency domain signal into an extended frequency domain signal with Hermitian symmetry, and perform an inverse fast Fourier transform on the extended frequency domain signal to obtain a precoded time domain signal; The compression module is configured to perform μ-law compression processing on the precoded time domain signal to obtain a compressed signal, and calculate a peak-to-average power ratio based on the compressed signal.

8. An electronic device, comprising: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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