Indoor communication method and system based on Li-Fi and Wi-Fi heterogeneity

Abstract

The application discloses an indoor communication method and system based on Li-Fi and Wi-Fi heterogeneity. The method comprises the following steps: index modulation is performed on the signal generated by the spatial modulator in the multiple optical line terminal Li-Fi signal generation module, and a to-be-transmitted electrical signal is obtained; direct modulation laser modulation is performed on the to-be-transmitted electrical signal, and a Li-Fi optical signal is obtained; the Li-Fi optical signal and a Wi-Fi signal are modulated, and a heterogeneous optical signal is obtained; the heterogeneous optical signals corresponding to the multiple optical line terminals are synthesized, a synthesized signal is obtained, and the synthesized signal is transmitted to an optical network unit through an optical fiber; the synthesized signal is converted and recovered in the optical network unit, and electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal are obtained. The method realizes the use of simple and low-power consumption devices on the indoor air interface side, reduces the complexity of digital signal processing and radio frequency front ends of the optical network unit, reduces the energy consumption and equipment cost of the system, and realizes the transmission of the Li-Fi and Wi-Fi mixed heterogeneous optical signal through the optical fiber network.

Description

Technical Field

[0001] This invention relates to the field of Li-Fi communication technology, and in particular to an indoor communication method and system based on the heterogeneity of Li-Fi and Wi-Fi. Background Technology

[0002] Currently, in order to meet the diverse IoT terminal access and high-capacity data transmission requirements in indoor environments, academia and industry have proposed relevant technical solutions to integrate Light Fidelity (Li-Fi) and Wireless Fidelity (Wi-Fi) signals to construct indoor heterogeneous networks (HetNets).

[0003] In some solutions, Li-Fi and Wi-Fi are aggregated and coordinated, and load balancing is used to improve the throughput and reduce the latency of the Wi-Fi network; other work considers contention and backoff mechanisms in small cell networks to reduce the average system latency.

[0004] Some studies use Markov decision processes to implement vertical handover strategies in multi-standard networks to achieve a trade-off between energy consumption and latency requirements; other studies use online learning algorithms to optimize user association strategies in hybrid Li-Fi / Wi-Fi networks to improve system throughput.

[0005] Other works incorporate QoS metrics such as packet loss rate and latency into load balancing strategies and propose neural network methods with adaptive target conditions to address the uneven load problem in multi-user scenarios, thereby improving network performance while better meeting quality requirements.

[0006] These solutions typically rely on complex signal processing and resource allocation strategies implemented on the indoor air interface side (such as the access point or optical network unit), including multi-standard signal processing, network switching decisions, and flexible resource configuration. This not only increases the complexity and energy consumption requirements of the local indoor air interface equipment, but also raises the overall system cost and maintenance difficulty. Summary of the Invention

[0007] Existing indoor communication technologies increase the processing complexity of optical network processing terminals, thereby increasing system energy consumption and overall cost.

[0008] To address the aforementioned issues, a heterogeneous indoor communication method and system based on Li-Fi and Wi-Fi is proposed. By incorporating a spatial modulator, a directly modulated laser, and a Mach-Zehnder modulator at the optical line terminal, the generated signal undergoes index modulation, directly modulated laser modulation, and Mach-Zehnder modulation to obtain a heterogeneous optical signal, which is then transmitted via optical fiber. This approach allows for the use of simple, low-power devices at the indoor air interface, reducing the complexity of local digital signal processing and RF front-end, and lowering system energy consumption and equipment costs. It achieves the transmission of hybrid heterogeneous Li-Fi and Wi-Fi optical signals via an optical fiber network. Furthermore, it fully utilizes the distributed architecture and passive optical splitting capabilities of passive optical network systems, thereby reducing the economic and maintenance burden associated with dense indoor cell deployments.

[0009] Firstly, an indoor communication method based on Li-Fi and Wi-Fi heterogeneity is provided, employing the following technical solution, including:

[0010] Step 100: At the optical line terminal, the signals generated by the spatial modulators in the multiple optical line terminal Li-Fi signal generation modules are indexed and modulated to obtain the electrical signal to be transmitted. The electrical signal to be transmitted is then directly modulated by laser to obtain the Li-Fi optical signal.

[0011] Step 200: At the optical line terminal, acquire the Wi-Fi signal to be transmitted, and perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain a heterogeneous optical signal of Li-Fi optical signal and Wi-Fi signal;

[0012] Step 300: Use a wavelength division multiplexer to combine the heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal, and transmit the combined signal to the optical network unit through an optical fiber.

[0013] Step 400: The optical network unit converts and recovers the synthesized signal to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, and transmits the electrical signals to the user through the optical device and the wireless transmission device, respectively.

[0014] In conjunction with the indoor communication method based on Li-Fi and Wi-Fi heterogeneity described in the first aspect of the present invention, in a first possible implementation, step 100 includes:

[0015] Step 110: Obtain the signal bit stream generated by the spatial modulator in the Li-Fi signal generation module of the optical line terminal;

[0016] Step 120: Divide the signal bit stream into an index bit group and a data bit group;

[0017] Step 130: Carrier modulation is performed on the index bit group and the data bit group to obtain the electrical signal to be transmitted.

[0018] In conjunction with the first possible embodiment of the first aspect of the present invention, in the second possible embodiment, step 100 further includes:

[0019] Step 140: Transmit the electrical signal to be transmitted to the direct-modulated laser;

[0020] Step 150: The direct-modulated laser converts the electrical signal to be transmitted to obtain a Li-Fi optical signal.

[0021] In conjunction with the second possible implementation of the first aspect of the present invention, in the third possible implementation, step 150 includes:

[0022] Step 151: The direct-modulated laser generates a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted;

[0023] Step 152: The direct-modulated laser modulates the laser signal according to the data bit group, so that the laser signal carries data information to obtain a Li-Fi optical signal.

[0024] In conjunction with the indoor communication method based on Li-Fi and Wi-Fi heterogeneity described in the first aspect of the present invention, in a fourth possible implementation, step 200 includes:

[0025] Step 210: Transmit the Li-Fi optical signal to the Mach-Zehnder modulator;

[0026] Step 220: Transmit the Wi-Fi signal to the Mach-Zehnder modulator through the radio frequency input port;

[0027] Step 230: The Mach-Zehnder modulator modulates the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal through double-sideband modulation.

[0028] In conjunction with the indoor communication method based on Li-Fi and Wi-Fi heterogeneity described in the first aspect of the present invention, in a fifth possible implementation, step 400 includes:

[0029] Step 410: Install a wavelength demultiplexer at the front end of the optical network unit;

[0030] Step 420: Use a wave demultiplexer to separate the synthesized signal into multiple heterogeneous optical signals.

[0031] In conjunction with the fifth possible embodiment of the first aspect of the present invention, in the sixth possible embodiment, step 400 further includes:

[0032] Step 430: Install a photodetector at the output of the wave demultiplexer;

[0033] Step 440: Use the photodetector to convert the heterogeneous optical signal into an electrical signal of the corresponding frequency;

[0034] Step 450: Perform local oscillator recovery on the electrical signal to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

[0035] Secondly, an indoor communication system based on Li-Fi and Wi-Fi heterogeneity includes:

[0036] Optical line terminal;

[0037] Optical network unit;

[0038] The optical network unit is optically connected to the optical line terminal;

[0039] The optical line terminal is used to index-modulate the signals generated by the spatial modulators in the multiple optical line terminal Li-Fi signal generation modules to obtain the electrical signal to be transmitted, to perform direct-modulation laser modulation on the electrical signal to be transmitted to obtain the Li-Fi optical signal, to acquire the Wi-Fi signal to be transmitted, and to perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain the heterogeneous optical signal of the Li-Fi optical signal and the Wi-Fi signal.

[0040] The optical network unit is used to combine heterogeneous optical signals corresponding to multiple optical line terminals using a wavelength division multiplexer to obtain a combined signal. The combined signal is then transmitted to the optical network unit via optical fiber. The combined signal is then converted and recovered to obtain electrical signals of different frequencies corresponding to Li-Fi and Wi-Fi signals, respectively. The electrical signals are then transmitted to the user via optical equipment and wireless transmission equipment, respectively.

[0041] In conjunction with the indoor communication system based on Li-Fi and Wi-Fi heterogeneity described in the second aspect of the present invention, in a first possible implementation,

[0042] The optical line terminal includes a Li-Fi signal generation module, a Wi-Fi signal generation module, a direct-modulated laser, and a wavelength division multiplexer. The Li-Fi signal generation module includes a spatial modulator, an adjustable frequency generator, and a carrier modulator. The Wi-Fi signal generation module includes a Wi-Fi signal source and a Mach-Zehnder modulator.

[0043] The spatial modulator, adjustable frequency generator, and carrier modulator are interconnected to generate the electrical signal to be transmitted.

[0044] The direct-modulated laser is used to generate a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted, and to modulate the laser signal according to the data bit group so that the laser signal carries data information to obtain a Li-Fi optical signal and transmit the Li-Fi optical signal to the Mach-Zehnder modulator.

[0045] The Wi-Fi signal source is communicatively connected to the Mach-Zehnder modulator and is used to generate Wi-Fi signals;

[0046] The Mach-Zehnder modulator is used to modulate the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal via double-sideband modulation;

[0047] The wavelength division multiplexer is used to combine heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal.

[0048] In conjunction with the Li-Fi and Wi-Fi heterogeneous indoor communication system described in the second aspect of the present invention, in a second possible embodiment, the optical network unit includes:

[0049] Wavelength demultiplexer;

[0050] Photodetector;

[0051] Local oscillator;

[0052] The wave demultiplexer, photodetector, and local oscillator are interconnected.

[0053] The wave demultiplexer is used to separate the synthesized signal into multiple heterogeneous optical signals;

[0054] The photodetector is used to convert the heterogeneous optical signal into an electrical signal of a corresponding frequency;

[0055] The local oscillator is used to recover the electrical signal, obtaining electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

[0056] This invention discloses an indoor communication method and system based on Li-Fi and Wi-Fi heterogeneity. By setting a spatial modulator, a direct-modulation laser, and a Mach-Zehnder modulator at the optical line terminal, the generated signal undergoes index modulation, direct-modulation laser modulation, and Mach-Zehnder modulation to obtain heterogeneous optical signals, which are then transmitted via optical fiber. This allows the use of simple, low-power devices at the indoor air interface, reducing the complexity of local digital signal processing and RF front-end, and lowering system energy consumption and equipment costs. It achieves the transmission of hybrid Li-Fi and Wi-Fi heterogeneous optical signals through an optical fiber network. It fully utilizes the distributed architecture and passive optical splitting capabilities of passive optical network systems, thereby reducing the economic and maintenance burden caused by dense indoor cell deployments. Attached Figure Description

[0057] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a structural diagram of an embodiment of an indoor communication system based on Li-Fi and Wi-Fi heterogeneity according to this application;

[0059] Figure 2 This is a schematic diagram illustrating the heterogeneity process between Li-Fi and Wi-Fi signals in this application;

[0060] Figure 3 This is a schematic diagram of Li-Fi signal communication in this application;

[0061] Figure 4 This is a flowchart of an embodiment of an indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to this application;

[0062] Figure 5 yes Figure 1 A flowchart of a specific implementation of S100;

[0063] Figure 6 yes Figure 5 A flowchart of a specific implementation method following S130;

[0064] Figure 7 yes Figure 6 A flowchart of a specific implementation of S150;

[0065] Figure 8 yes Figure 4 A flowchart of a specific implementation of S200;

[0066] Figure 9 yes Figure 4 A flowchart of a specific implementation of the S400;

[0067] Figure 10 yes Figure 9 A flowchart of a specific implementation following S420. Detailed Implementation

[0068] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0069] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings of this application are intended to cover non-exclusive inclusion.

[0071] 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 one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0072] Name Explanation

[0073] Li-Fi: Light Fidelity, a technology that preserves optical fidelity.

[0074] Wi-Fi: Wireless Fidelity;

[0075] PON: Passive Optical Network;

[0076] OLT: Optical Line Terminal;

[0077] ONU: Optical Network Unit;

[0078] MUX: Multiplexer, wavelength division multiplexer;

[0079] DEMUX: Demultiplexer, Wavelength decomposition and multiplexing device;

[0080] PD: Photodiode, photodetector;

[0081] SM: Spatial Modulation;

[0082] MZM: Mach-Zehnder Modulator.

[0083] MUX: Multiplexer, wavelength division multiplexer;

[0084] DEMUX: Demultiplexer, Wavelength decomposition and multiplexing device;

[0085] PD: Photodiode, photodetector;

[0086] SM: Spatial Modulation;

[0087] MZM: Mach-Zehnder Modulator.

[0088] The processing of multiple signal standards, network switching decisions, and resource allocation schemes used in existing indoor communication technologies increase the processing complexity of optical network processing terminals, thereby increasing the system's energy consumption and overall cost.

[0089] To address the above issues, a method and system for indoor communication based on the heterogeneity of Li-Fi and Wi-Fi is proposed.

[0090] Firstly, an indoor communication method based on Li-Fi and Wi-Fi heterogeneity is provided, employing the following technical solutions, such as... Figure 4 , Figure 4 This is a flowchart of an embodiment of an indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to this application; including:

[0091] S100. At the optical line terminal, the signals generated by the spatial modulators in the multiple optical line terminal Li-Fi signal generation modules are indexed and modulated to obtain the electrical signal to be transmitted. The electrical signal to be transmitted is then directly modulated by laser to obtain the Li-Fi optical signal.

[0092] like Figure 1 , Figure 1 This is a structural diagram of an embodiment of an indoor communication system based on Li-Fi and Wi-Fi heterogeneity according to this application. The system includes: an optical line terminal (OLT) and an optical network unit (ONU). Each user's OLT includes a Li-Fi signal generation module, a Wi-Fi signal generation module, a directly modulated laser, and a wavelength division multiplexer (MUX). The Li-Fi signal generation module includes a spatial modulator (Li-Fi SM DSP Block), an adjustable frequency generator, and a carrier modulator. The Wi-Fi signal generation module includes a Wi-Fi signal source and a Mach-Zehnder modulator (MZM), wherein the Mach-Zehnder modulator is the device for Wi-Fi signal input. The ONU includes: a wavelength division multiplexer (DEMUX), a photodetector (PD), and a local oscillator.

[0093] In this embodiment, the spatial modulators and Wi-Fi signal sources for different users are adjusted and controlled by an adaptive controller. In this embodiment, to reduce the complexity and power consumption of the optical network unit in the system, a spatial modulator and a direct-modulated laser are set at the optical line terminal to obtain the Li-Fi optical signal.

[0094] In a preferred embodiment, such as Figure 5 , Figure 5 yes Figure 1 A flowchart of a specific implementation of S100; S100 includes: S110, acquiring the signal bit stream generated by the spatial modulator in the Li-Fi signal generation module of the optical line terminal; S120, dividing the signal bit stream into index bit groups (Carrier Selection Bits) and data bit groups (Data Bits); S130, performing carrier modulation on the index bit groups (Carrier Selection Bits) and data bit groups (Data Bits) to obtain the electrical signal to be transmitted, such as... Figure 1 In this embodiment, the index bit group is used to inform the direct-modulated laser of the optical signal mode or parameters to be selected, such as wavelength, polarization direction, and phase, during modulation. The data bit group is used to modulate the intensity and amplitude of the optical signal to carry data information. Figure 1The CSB in the text stands for Carrier Selection Bits, also known as carrier selection bits.

[0095] In a preferred embodiment, such as Figure 6 , Figure 6 yes Figure 5 The flowchart shows a specific implementation method following S130; S100 further includes: S140, transmitting the electrical signal to be transmitted to the direct-modulated laser; S150, the direct-modulated laser converts the electrical signal to be transmitted to obtain a Li-Fi optical signal. :

[0096] (1)

[0097] In the formula, It is the laser power. It is the optical carrier angular frequency. The center angular frequency of the Li-Fi signal driving the modulator is represented by t, the signal transmission time is t, and e is the natural constant.

[0098] For each group of users, the wavelength of the optical carrier is different, which can be achieved by adjusting the center frequency of the laser in the OLT.

[0099] In a preferred embodiment, such as Figure 7 , Figure 7 yes Figure 6 A flowchart of a specific implementation of S150; S150 includes: S151, a direct-modulated laser generates a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted; S152, the direct-modulated laser modulates the laser signal according to the data bit group, so that the laser signal carries data information to obtain a Li-Fi optical signal.

[0100] like Figure 3 , Figure 3 This is a schematic diagram of Li-Fi signal communication in this application. In this embodiment, taking 4 LEDs (optical devices) as an example, at the optical line terminal, data bits are loaded onto the carrier frequency of the corresponding frequency according to the index bit group (Carrier Selection Bits). Two frequency index bits constitute an index bit group (Carrier Selection Bits). Figure 3The index bit group in the image is 00 to 11, representing the transmission carrier frequencies f1 to f4 respectively. After transmission through the proposed Passive Optical Network (PON), the signals of the four frequencies are transmitted using four LEDs for index modulation. At any given time, only one LED is communicating. At the receiving end (optical network unit), the index bit group (Carrier Selection Bits) and data bit group can be demodulated using the maximum likelihood ratio based on the received signal and channel estimation technology to complete the Li-Fi signal communication.

[0101] S200. At the optical line terminal, acquire the Wi-Fi signal to be transmitted, and perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain a heterogeneous optical signal of Li-Fi optical signal and Wi-Fi signal.

[0102] In a preferred embodiment, such as Figure 8 , Figure 8 yes Figure 4 A flowchart of a specific implementation of S200; S200 includes: S210, transmitting the Li-Fi optical signal to the Mach-Zehnder modulator; S220, transmitting the Wi-Fi signal to the Mach-Zehnder modulator through the radio frequency input port; S230, the Mach-Zehnder modulator modulates the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal through double-sideband modulation.

[0103] In this embodiment, the Mach-Zehnder modulator first converts the input Wi-Fi signal into an optical signal, and then modulates the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal using double-sideband modulation. Since the Li-Fi frequency and the Wi-Fi signal frequency are in different frequency bands, they will not affect each other's communication quality.

[0104] In this embodiment, in order to transmit multiple signals in the optical fiber to meet the communication and positioning needs of different users and achieve low-power multi-service transmission, a Mach-Zehnder modulator is set at the optical line terminal to perform Mach-Zehnder modulation (MZM) on the Wi-Fi signal and the Li-Fi optical signal, and fuse them together to obtain heterogeneous signals. :

[0105] (2),

[0106] (2) In the formula, This indicates the center angular frequency of the Wi-Fi signal driving the modulator. It is the modulator half-wave voltage. It is the amplitude of the Wi-Fi radio frequency signal. This represents the Nth-order Bessel function of the first kind. From this equation, it can be seen that, through direct laser modulation and MZM modulation, the Li-Fi / Wi-Fi signals are successfully modulated onto the same spectrum. It is the optical carrier angular frequency. The frequency of the Li-Fi signal driving the modulator is represented by the center angular frequency, and t is the signal transmission time. This is a Li-Fi optical signal.

[0107] The heterogeneous fusion process of Li-Fi / Wi-Fi signals is as follows: Figure 2 , Figure 2 This is a schematic diagram illustrating the heterogeneity process between Li-Fi and Wi-Fi signals in this application. Figure 2 The system includes two sets of user optical line terminals. The signal in the dashed box is used for Li-Fi optical communication, with four carrier frequencies of f1-f4. The sideband signal furthest from the spectrum is the Wi-Fi signal with carrier frequency f5. ③ The Li-Fi / Wi-Fi heterogeneous signal, which is obtained by demultiplexing the two sets of optical signals with λ1 and λ2 as center frequencies, can be easily demultiplexed using a demultiplexer. The Li-Fi index modulation and Wi-Fi transmission are then performed in the subsequent optical network units.

[0108] Figure 2 In the diagram, ①, ④, ⑤, and ⑦ represent the Li-Fi optical signals converted from the two user groups, ② and ⑥ represent the heterogeneous signals obtained through Mach-Zehnder modulation (MZM), and ③ represents the Li-Fi / Wi-Fi heterogeneous signal obtained through demultiplexing.

[0109] S300 uses a wavelength division multiplexer to combine heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal, which is then transmitted to the optical network unit via optical fiber.

[0110] S400 converts and recovers the synthesized signal in the optical network unit to obtain electrical signals of different frequencies corresponding to Li-Fi and Wi-Fi signals, and transmits the electrical signals to the user through optical equipment and wireless transmission equipment, respectively.

[0111] In a preferred embodiment, such as Figure 9 , Figure 9 yes Figure 4 A flowchart of a specific implementation of S400; S400 includes S410, setting a wavelength demultiplexer at the front end of the optical network unit; S420, using the wavelength demultiplexer to separate the synthesized signal into multiple heterogeneous optical signals.

[0112] In a preferred embodiment, such as Figure 10 , Figure 10 yes Figure 9The flowchart below shows a specific implementation following S420. S400 also includes: S430, setting a photodetector at the output of the wave demultiplexer; S440, using the photodetector to convert the heterogeneous optical signal into an electrical signal of the corresponding frequency; S450, performing local oscillator recovery on the electrical signal to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

[0113] In this embodiment, all heterogeneous optical signals generated by users are combined into a single optical signal using a wavelength division multiplexer and transmitted through an optical fiber. At the front end of the optical network unit (ONU), another wavelength division multiplexer separates the two heterogeneous optical signals with different center frequencies. The two separated optical signals then undergo photoelectric conversion by a photodetector within the ONU. The electrical signals are then recovered using local oscillators of different frequencies, and finally transmitted via LEDs and antennas for Li-Fi and Wi-Fi communication, respectively. Throughout the system, passive components are used to implement a low-power, multi-service PON system for Li-Fi and Wi-Fi communication.

[0114] By incorporating spatial modulators, direct-modulated lasers, and Mach-Zehnder modulators at the optical line terminal (OLT), heterogeneous optical signals are obtained through index modulation, direct-modulated laser modulation, and Mach-Zehnder modulation of the generated signals. These signals are then transmitted via optical fiber. This approach allows for the use of simple, low-power devices at the indoor air interface, reducing the complexity of local digital signal processing and RF front-ends, and lowering system energy consumption and equipment costs. It enables the transmission of hybrid heterogeneous Li-Fi and Wi-Fi optical signals via optical fiber networks. Furthermore, it fully utilizes the distributed architecture and passive optical splitting capabilities of passive optical network systems, thereby reducing the economic and maintenance burden associated with dense indoor deployments.

[0115] Secondly, an indoor communication system based on Li-Fi and Wi-Fi heterogeneity includes an optical line terminal and an optical network unit; the optical network unit and the optical line terminal are optically connected; the optical line terminal is used to index-modulate the signals generated by the spatial modulators in the Li-Fi signal generation modules of multiple optical line terminals to obtain the electrical signal to be transmitted, to perform direct-modulation laser modulation on the electrical signal to be transmitted to obtain the Li-Fi optical signal, to acquire the Wi-Fi signal to be transmitted, and to perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain the heterogeneous optical signal of the Li-Fi optical signal and the Wi-Fi signal;

[0116] The optical network unit is used to combine heterogeneous optical signals corresponding to multiple optical line terminals using a wavelength division multiplexer to obtain a combined signal. The combined signal is then transmitted to the optical network unit through optical fiber, where it is converted and restored to obtain electrical signals of different frequencies corresponding to Li-Fi and Wi-Fi signals. These electrical signals are then transmitted to the user through optical equipment and wireless transmission equipment, respectively.

[0117] Preferably, the optical line terminal includes a Li-Fi signal generation module, a Wi-Fi signal generation module, a direct-modulated laser, and a wavelength division multiplexer. The Li-Fi signal generation module includes a spatial modulator, an adjustable frequency generator, and a carrier modulator; the Wi-Fi signal generation module includes a Wi-Fi signal source and a Mach-Zehnder modulator.

[0118] The spatial modulator, adjustable frequency generator, and carrier modulator are interconnected to generate the electrical signal to be transmitted.

[0119] A direct-modulated laser is used to generate a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted, and to modulate the laser signal according to the data bit group so that the laser signal carries data information, thereby obtaining a Li-Fi optical signal and transmitting the Li-Fi optical signal to a Mach-Zehnder modulator.

[0120] The Wi-Fi signal source is communicatively connected to a Mach-Zehnder modulator to generate Wi-Fi signals;

[0121] Mach-Zehnder modulators are used to modulate Wi-Fi signals onto the outer sidebands of Li-Fi optical signals via double-sideband modulation.

[0122] Wavelength division multiplexers are used to combine heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal.

[0123] Preferably, the optical network unit includes a wave demultiplexer, a photodetector, and a local oscillator; the wave demultiplexer, photodetector, and local oscillator are interconnected; the wave demultiplexer is used to separate the synthesized signal into multiple heterogeneous optical signals; the photodetector is used to convert the heterogeneous optical signals into electrical signals of corresponding frequencies; and the local oscillator is used to perform local oscillator recovery on the electrical signals to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

[0124] This invention discloses an indoor communication method and system based on Li-Fi and Wi-Fi heterogeneity. By setting a spatial modulator, a direct-modulation laser, and a Mach-Zehnder modulator at the optical line terminal, the generated signal undergoes index modulation, direct-modulation laser modulation, and Mach-Zehnder modulation to obtain heterogeneous optical signals, which are then transmitted via optical fiber. This allows the use of simple, low-power devices at the indoor air interface, reducing the complexity of local digital signal processing and RF front-end, and lowering system energy consumption and equipment costs. It achieves the transmission of hybrid Li-Fi and Wi-Fi heterogeneous optical signals through an optical fiber network. It fully utilizes the distributed architecture and passive optical splitting capabilities of passive optical network systems, thereby reducing the economic and maintenance burden caused by dense indoor cell deployments.

[0125] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An indoor communication method based on Li-Fi and Wi-Fi heterogeneity, characterized in that it includes: Step 100: At the optical line terminal, the signals generated by the spatial modulators in the multiple optical line terminal Li-Fi signal generation modules are indexed and modulated to obtain the electrical signal to be transmitted. The electrical signal to be transmitted is then directly modulated by laser to obtain the Li-Fi optical signal. Step 200: At the optical line terminal, acquire the Wi-Fi signal to be transmitted, and perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain a heterogeneous optical signal of Li-Fi optical signal and Wi-Fi signal; Step 300: Use a wavelength division multiplexer to combine the heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal, and transmit the combined signal to the optical network unit through an optical fiber. Step 400: The optical network unit converts and recovers the synthesized signal to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, and transmits the electrical signals to the user through the optical device and the wireless transmission device, respectively.

2. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 1, characterized in that, Step 100 includes: Step 110: Obtain the signal bit stream generated by the spatial modulator in the Li-Fi signal generation module of the optical line terminal; Step 120: Divide the signal bit stream into an index bit group and a data bit group; Step 130: Carrier modulation is performed on the index bit group and data bit group to obtain the electrical signal to be transmitted.

3. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 2, characterized in that, Step 100 further includes: Step 140: Transmit the electrical signal to be transmitted to the direct-modulated laser; Step 150: The direct-modulated laser converts the electrical signal to be transmitted to obtain a Li-Fi optical signal.

4. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 3, characterized in that, Step 150 includes: Step 151: The direct-modulated laser generates a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted; Step 152: The direct-modulated laser modulates the laser signal according to the data bit group, so that the laser signal carries data information to obtain a Li-Fi optical signal.

5. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 1, characterized in that, Step 200 includes: Step 210: Transmit the Li-Fi optical signal to the Mach-Zehnder modulator; Step 220: Transmit the Wi-Fi signal to the Mach-Zehnder modulator through the radio frequency input port; Step 230: The Mach-Zehnder modulator modulates the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal through double-sideband modulation.

6. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 1, characterized in that, Step 400 includes: Step 410: Install a wavelength demultiplexer at the front end of the optical network unit; Step 420: Use a wave demultiplexer to separate the synthesized signal into multiple heterogeneous optical signals.

7. The indoor communication method based on Li-Fi and Wi-Fi heterogeneity according to claim 6, characterized in that, Step 400 further includes: Step 430: Install a photodetector at the output of the wave demultiplexer; Step 440: Use the photodetector to convert the heterogeneous optical signal into an electrical signal of the corresponding frequency; Step 450: Perform local oscillator recovery on the electrical signal to obtain electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

8. An indoor communication system based on Li-Fi and Wi-Fi heterogeneity, employing the indoor communication method based on Li-Fi and Wi-Fi heterogeneity as described in any one of claims 1-7, characterized in that, include: Optical line terminal; Optical network unit; The optical network unit is optically connected to the optical line terminal; The optical line terminal is used to index-modulate the signals generated by the spatial modulators in the multiple optical line terminal Li-Fi signal generation modules to obtain the electrical signal to be transmitted, to perform direct-modulation laser modulation on the electrical signal to be transmitted to obtain the Li-Fi optical signal, to acquire the Wi-Fi signal to be transmitted, and to perform Mach-Zehnder modulation on the Li-Fi optical signal and the Wi-Fi signal to obtain the heterogeneous optical signal of the Li-Fi optical signal and the Wi-Fi signal. The optical network unit is used to combine heterogeneous optical signals corresponding to multiple optical line terminals using a wavelength division multiplexer to obtain a combined signal. The combined signal is then transmitted to the optical network unit via optical fiber. The combined signal is then converted and recovered to obtain electrical signals of different frequencies corresponding to Li-Fi and Wi-Fi signals, respectively. The electrical signals are then transmitted to the user via optical equipment and wireless transmission equipment, respectively.

9. The indoor communication system based on Li-Fi and Wi-Fi heterogeneity according to claim 8, characterized in that, The optical line terminal includes a Li-Fi signal generation module, a Wi-Fi signal generation module, a direct-modulated laser, and a wavelength division multiplexer. The Li-Fi signal generation module includes a spatial modulator, an adjustable frequency generator, and a carrier modulator. The Wi-Fi signal generation module includes a Wi-Fi signal source and a Mach-Zehnder modulator. The spatial modulator, adjustable frequency generator, and carrier modulator are interconnected to generate the electrical signal to be transmitted. The direct-modulated laser is used to generate a laser signal of a specified frequency according to the index bit group of the electrical signal to be transmitted, and to modulate the laser signal according to the data bit group so that the laser signal carries data information, thereby obtaining a Li-Fi optical signal and transmitting the Li-Fi optical signal to the Mach-Zehnder modulator. The Wi-Fi signal source is communicatively connected to the Mach-Zehnder modulator and is used to generate Wi-Fi signals; The Mach-Zehnder modulator is used to modulate the Wi-Fi signal onto the outer sideband of the Li-Fi optical signal via double-sideband modulation; The wavelength division multiplexer is used to combine heterogeneous optical signals corresponding to multiple optical line terminals to obtain a combined signal.

10. The indoor communication system based on Li-Fi and Wi-Fi heterogeneity according to claim 8, characterized in that, The optical network unit includes: Wavelength demultiplexer; Photodetector; Local oscillator; The wave demultiplexer, photodetector, and local oscillator are interconnected. The wave demultiplexer is used to separate the synthesized signal into multiple heterogeneous optical signals; The photodetector is used to convert the heterogeneous optical signal into an electrical signal of a corresponding frequency; The local oscillator is used to recover the electrical signal, obtaining electrical signals of different frequencies corresponding to the Li-Fi signal and the Wi-Fi signal, respectively.

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