A receiving terminal, a transmitting terminal and an optical communication method based on optical communication

Abstract

This invention relates to a receiving terminal, a transmitting terminal, and an optical communication method based on optical communication. A photoelectric detection module receives optical signals within a MIMO channel and converts them into electrical signals. A sensor module includes a positioning sensor for collecting location information from the user terminal. A signal recovery module, after acquiring the user terminal's location information, uses locally stored channel state information to recover the electrical signal; or, by establishing a MIMO channel model and solving for the channel state information, it uses the channel state information to recover the electrical signal. A data processing module processes the recovered electrical signal to obtain the source signal. A sink receives the source signal and sends communication request information. This invention can meet the communication needs of users in indoor mobile scenarios. By using the sensor module to obtain the location feedback from the photoelectric detection module and feeding it back to the signal recovery module for modeling, the channel state information of the MIMO channel is obtained to recover the signal, achieving efficient communication.

Description

Technical Field

[0001] This invention relates to the field of indoor communication technology, and in particular to a receiving terminal, a transmitting terminal, and an optical communication method based on optical communication. Background Technology

[0002] Visible Light Communication (VLC) refers to a communication method that uses visible light as an information carrier to directly transmit light signals through the air. Using light-emitting diodes (LEDs) for indoor visible light communication is a promising approach. Because the illumination models for light sources (such as the Lambertian scattering model) are relatively mature and the VLC communication model is relatively fixed, the optical communication channel is a constant-parameter channel. This means that once the intelligent receiving module obtains the location of the intelligent receiving module and transmitter through positioning, channel state information can be obtained through channel modeling to recover the signal. However, in indoor VLC communication, due to the fixed position of the light source and its physical characteristics, it is difficult to meet the requirements of intelligent communication. When a user moves indoors, the light source needs to emit a wide beamwidth to track the user. However, when the user stops moving and requires large data communication, the wide beamwidth communication method consumes more energy. In fact, in the central area of ​​the building (the area with high communication activity), a narrower beamwidth can meet the communication requirements, thus saving more energy. Therefore, how to intelligently switch between these beamwidths is a problem that urgently needs to be solved.

[0003] With increasing demands for speed and quality in optical communication, MIMO technology is being used more and more in indoor optical communication. However, MIMO channels are more complex, and obtaining channel state information is more complicated. Due to channel interference and other factors in MIMO indoor communication, intelligent receiver modules are essential for obtaining channel state information, which increases communication overhead and system complexity to some extent. Current MIMO-VLC communication systems still require traditional channel estimation to obtain channel state information. Signal recovery methods based on MIMO channels include traditional channel estimation methods based on training sequences, adaptive equalizer methods, and blind estimation methods. These methods still have some drawbacks, as detailed below:

[0004] (1) In traditional communication methods that use training sequences for channel estimation, the length of the training sequence has a significant impact on the accuracy of the estimated channel state information. That is, the length of the training sequence required to obtain accurate channel information is relatively long. Furthermore, in mobile communication scenarios, channel estimation must be performed before communication, which can lead to untimely updates of channel information and a high bit error rate.

[0005] (2) While adaptive equalizers overcome the update problem of changing channels, they require more complex algorithms to implement. Furthermore, because the filter tap coefficients are determined by the received signal, adaptive equalizers are sensitive to signal quality and easily affected by it; they cannot achieve signal recovery when the signal quality is poor. Moreover, adaptive equalizers still require training sequences.

[0006] (3) Blind estimation, although it does not require training sequences, has a large error and its accuracy is limited by the transmitted signal. On the other hand, blind estimation can only obtain statistical information about the channel and cannot obtain specific characteristics of the channel. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a receiving terminal, transmitting terminal and optical communication method based on optical communication, which can meet the communication needs of users in different indoor scenarios. In the communication process, the channel state information of the MIMO channel is obtained to recover the signal, skipping the process of sending training sequences to estimate the channel in the communication process, and transforming the communication problem into a simple indoor positioning problem, so as to achieve the purpose of efficient communication.

[0008] To address the aforementioned technical problems, this invention provides a receiving terminal based on optical communication, comprising:

[0009] The photoelectric detection module receives optical signals within the MIMO channel and converts them into electrical signals. The photoelectric detection module includes multiple photodetectors, each of which receives different optical signals. After the optical signals are converted into electrical signals, they are all recovered by a signal recovery module.

[0010] The sensor module includes a positioning sensor for collecting location information from the user terminal.

[0011] A signal recovery module is provided, which is used to recover the electrical signal using locally stored channel state information after acquiring the location information of the user terminal; or to obtain channel state information by establishing a MIMO channel model and then using the channel state information to recover the electrical signal; wherein, when the location information of the user terminal is stored locally, the electrical signal is recovered using the locally stored channel state information associated with the location information; when the location information of the user terminal is not stored locally, the channel state information is obtained by establishing the MIMO channel model and then stored locally; wherein, the MIMO channel model is associated with the location information of the user terminal;

[0012] The data processing module is used to process the electrical signal recovered by the signal recovery module to obtain the source signal;

[0013] The receiver receives the source signal and sends communication request information.

[0014] In one embodiment of the present invention, the positioning sensor is set independently or integrated with the transmitting terminal.

[0015] In one embodiment of the present invention, the sensor module further includes a motion sensor, which is used to collect information on whether the user terminal is moving; when the user terminal moves, the communication requirement information includes control information for adjusting the beamwidth of the light source.

[0016] In one embodiment of the present invention, the sensor module further includes an image sensor, which is used to collect information on whether the photoelectric detection module lacks a light source link; when the photoelectric detection module lacks a light source link, the communication requirement information includes control information for adjusting the light source beamwidth.

[0017] In one embodiment of the present invention, the signal recovery module is provided with a memory, and the location information of the user terminal and the associated channel state information are locally stored in the memory; wherein, the storage strategy of the channel state information in the memory includes channel state information estimated using the direct component LOS, and channel state information estimated using the direct and reflected components NLOS.

[0018] A transmitting terminal based on optical communication includes,

[0019] A signal source is used to generate a source signal;

[0020] A data processing module is used to process the source signal to obtain a modulated signal;

[0021] The sensor module includes a positioning sensor for collecting location information from the user terminal.

[0022] A signal pre-recovery module is provided, which, after acquiring the location information of the user terminal, uses locally stored channel state information to pre-recover the modulated signal; or obtains channel state information by establishing a MIMO channel model and uses the channel state information to pre-recover the modulated signal; wherein, when the location information of the user terminal is stored locally, the locally stored channel state information associated with the location information is used to pre-recover the modulated signal; when the location information of the user terminal is not stored locally, the MIMO channel model is established, the channel state information is obtained, and the obtained channel state information is stored locally; wherein, the MIMO channel model is associated with the location information of the user terminal;

[0023] An electro-optical driving module is used to drive a light source to emit light and can control and change the beamwidth of the light source.

[0024] The light source is used to convert the modulated signal processed by the signal pre-recovery module into an optical signal and send it out. The light source includes multiple light sources, which are simultaneously driven by the electro-optic driving module. The multiple light sources emit different signals at the same time and form a MIMO signal through the MIMO channel.

[0025] In one embodiment of the present invention, the positioning sensor is either independently configured or integrated with a receiving terminal.

[0026] In one embodiment of the present invention, a link prediction module is further included, which is used to preprocess the source data according to the communication requirements information of the destination before the data processing module processes the source data.

[0027] In one embodiment of the present invention, the sensor module further includes a motion sensor, which is used to collect information on whether the user terminal is moving; when the user terminal moves, the communication requirement information includes control information for adjusting the beamwidth of the light source.

[0028] In one embodiment of the present invention, the sensor module further includes an image sensor, which is used to collect information on whether the receiving end lacks a light source link; when the receiving end lacks a light source link, the communication requirement information includes control information for adjusting the light source beamwidth.

[0029] In one embodiment of the present invention, the signal pre-recovery module is provided with a memory, and the location information of the user terminal and the associated channel state information are locally stored in the memory; wherein, the storage strategy of the channel state information in the memory includes channel state information estimated using the direct component LOS, and channel state information estimated using the direct and reflected components NLOS.

[0030] An indoor optical communication method includes the following steps:

[0031] The source generates the source signal;

[0032] The source signal is preprocessed according to the communication requirements of the destination;

[0033] The preprocessed source signal is modulated to obtain the modulated signal;

[0034] The light source converts the modulation signal into an optical signal and transmits it through a MIMO channel;

[0035] Receive optical signals within the MIMO channel and convert them into electrical signals;

[0036] The electrical signal is recovered using channel state information. Specifically, when the user terminal's location information is stored locally, the electrical signal is recovered using the locally stored channel state information associated with that location information. When the user terminal's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the electrical signal is recovered using the obtained channel state information, which is then stored locally. The MIMO channel model is associated with the location information of the light source and the user terminal.

[0037] The demodulated and recovered electrical signal is sent to the sink.

[0038] An indoor optical communication method includes the following steps:

[0039] The source generates the source signal;

[0040] The source signal is preprocessed according to the communication requirements of the destination;

[0041] The preprocessed source signal is modulated to obtain the modulated signal;

[0042] The modulation signal is pre-recovered using channel state information, wherein when the user's location information is stored locally, the modulation signal is pre-recovered using the locally stored channel state information associated with that location information; when the user's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the obtained channel state information is used to pre-recover the modulation signal, and the obtained channel state information is stored locally; wherein the MIMO channel model is associated with the location information of the light source and the location information of the user.

[0043] The light source converts the pre-recovered modulation signal into an optical signal and transmits it through a MIMO channel;

[0044] Receive optical signals within the MIMO channel and convert them into electrical signals;

[0045] The demodulated and recovered electrical signal is sent to the sink.

[0046] In one embodiment of the present invention, the location information of the user terminal includes the position coordinates of the light source, the position coordinates of the photodetector, the orientation of the photodetector, and the beamwidth of the light source; the above information is transmitted through the channel impulse response h. total,ji The channel state information is obtained; where h total,ji The formula is as follows:

[0047]

[0048] Among them, T i Let R be the three-dimensional position coordinates of the i-th light source. j Let be the three-dimensional position coordinates of the j-th photodetector, α be the angle between the projection of the receiving terminal's orientation onto the XY plane and the x-axis, β be the angle between the receiving terminal's orientation and the z-axis, and Φ be the angle between the receiving terminal's orientation and the z-axis. 1 / 2 It is the half-power angle of the light source (i.e., the beamwidth of the light source); τ los,ji It is the time delay of the direct optical link (LOS), τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji (τ nlos,ji The specific delay τ under the NLOS link is... nlos,ji The channel DC gain corresponding to the component, H los,ji (0) and A nlos,ji Both are functions of position coordinates, and are calculated separately using the position coordinates of the photodetector and the light source.

[0049] When recovering the signal at the receiving terminal, in addition to obtaining the position coordinates and orientation angle of the photodetector from the sensor module, it is still necessary to obtain the half-power angle of the light source through the communication link.

[0050] When performing signal pre-recovery at the transmitting terminal, it is only necessary to obtain the position coordinates and orientation angle of the photodetector from the sensor module.

[0051] The technical solution of the present invention has the following advantages compared with the prior art:

[0052] (1) This invention can meet the communication needs of users in indoor mobile scenarios. During the communication process, the location information of the receiving end is obtained to model the signal, obtain the channel state information of the MIMO channel to recover the signal, eliminate the influence of inter-channel interference, skip the process of sending training sequences to estimate the channel during the communication process, and the obtained channel state is not affected by sudden noise at the time of communication, and has strong robustness. It transforms the complex communication problem into a simple indoor positioning problem, reduces communication overhead, and achieves the goal of efficient communication.

[0053] (2) The signal recovery module obtains the user's location through the sensor module, uses the locally stored channel state information or establishes a MIMO channel model to obtain the channel state information, uses the channel state information to distinguish and recover the electrical signal converted by the photoelectric detection module, and stores the channel state information of this location locally to solve the problem that the signal cannot be directly distinguished and recovered due to the interference between MIMO channels.

[0054] (3) The signal pre-recovery module of the intelligent transmission module addresses the problem of noise amplification in MIMO channels by using channel state information to pre-recover the signal at the transmitting end, making signal recovery at the receiving end simple and preventing noise from being amplified, thus reducing the bit error rate.

[0055] (4) The embedded memory in the signal recovery module and the signal pre-recovery module allows communication at the same location to directly look up the channel status information, making communication more convenient.

[0056] (5) The use of MIMO technology and multiple LEDs increases the communication capacity, while multiple photodetectors (PDs) increases the receiving sensitivity of the receiving terminal, thus improving the overall performance of the communication system. Attached Figure Description

[0057] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0058] Figure 1 This is a block diagram of the communication system of indoor MIMO-VLC according to Embodiment 1 of the present invention;

[0059] Figure 2 This is a block diagram of the communication system of indoor MIMO-VLC according to Embodiment 2 of the present invention;

[0060] (a) Block diagram of the communication system where the positioning sensor is located at the intelligent receiving module;

[0061] (b) Block diagram of the communication system in which the positioning sensor is located in the intelligent transmission module;

[0062] Figure 3 This is a comparison diagram of the estimated channel and the actual channel of the high-efficiency communication system of indoor MIMO-VLC in Embodiment 1 of the present invention;

[0063] (a) Comparison of the estimated channel and the actual channel when the intelligent receiving module is in the center of the room;

[0064] (b) Comparison of channel estimation and actual channel results when the intelligent receiver module is in an indoor corner;

[0065] Figure 4 This is a diagram showing the bit error rate of the high-efficiency indoor MIMO-VLC communication system in various indoor areas according to Embodiment 1 of the present invention.

[0066] (a) Only LOS components are considered for channel modeling;

[0067] (b) Considering the LOS and NLOS components for channel modeling;

[0068] Figure 5 This is a bit error rate performance curve of the indoor MIMO-VLC communication system of Embodiment 1 and Embodiment 2 of the present invention in a corner of a room. Detailed Implementation

[0069] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0070] This invention provides a receiving terminal based on optical communication, comprising:

[0071] The photoelectric detection module receives optical signals within the MIMO channel and converts them into electrical signals. The photoelectric detection module includes multiple photodetectors, each of which receives different optical signals. After the optical signals are converted into electrical signals, they are all recovered by a signal recovery module.

[0072] The sensor module includes a positioning sensor for collecting location information from the user terminal.

[0073] A signal recovery module is provided, which is used to recover the electrical signal using locally stored channel state information after acquiring the location information of the user terminal; or to obtain channel state information by establishing a MIMO channel model and then using the channel state information to recover the electrical signal; wherein, when the location information of the user terminal is stored locally, the electrical signal is recovered using the locally stored channel state information associated with the location information; when the location information of the user terminal is not stored locally, the channel state information is obtained by establishing the MIMO channel model and then stored locally; wherein, the MIMO channel model is associated with the location information of the user terminal;

[0074] The data processing module is used to process the electrical signal recovered by the signal recovery module to obtain the source signal;

[0075] The receiver receives the source signal and sends communication request information.

[0076] In the above scheme, the positioning sensor is set independently or integrated with the receiving terminal.

[0077] Furthermore, the sensor module also includes a motion sensor, which is used to collect information on whether the user terminal is moving; when the user terminal moves, the communication request information includes control information for adjusting the beamwidth of the light source.

[0078] Furthermore, the sensor module also includes an image sensor, which is used to collect information on whether the photoelectric detection module lacks a light source link; when the photoelectric detection module lacks a light source link, the communication requirement information includes control information for adjusting the light source beamwidth.

[0079] Furthermore, the signal recovery module includes a memory, in which the location information of the user terminal and the associated channel state information are locally stored; wherein, the storage strategy for the channel state information in the memory includes channel state information estimated using the direct component LOS, and channel state information estimated using the direct and reflected components NLOS.

[0080] A transmitting terminal based on optical communication includes,

[0081] A signal source is used to generate a source signal;

[0082] A data processing module is used to process the source signal to obtain a modulated signal;

[0083] The sensor module includes a positioning sensor for collecting location information from the user terminal.

[0084] A signal pre-recovery module is provided, which, after acquiring the location information of the user terminal, uses locally stored channel state information to pre-recover the modulated signal; or obtains channel state information by establishing a MIMO channel model and uses the channel state information to pre-recover the modulated signal; wherein, when the location information of the user terminal is stored locally, the locally stored channel state information associated with the location information is used to pre-recover the modulated signal; when the location information of the user terminal is not stored locally, the MIMO channel model is established, the channel state information is obtained, and the obtained channel state information is stored locally; wherein, the MIMO channel model is associated with the location information of the user terminal;

[0085] An electro-optical driving module is used to drive a light source to emit light and can control and change the beamwidth of the light source.

[0086] The light source is used to convert the modulated signal processed by the signal pre-recovery module into an optical signal and send it out. The light source includes multiple light sources, which are simultaneously driven by the electro-optic driving module. The multiple light sources emit different signals at the same time and form a MIMO signal through the MIMO channel.

[0087] The positioning sensor can be set independently or integrated with the transmitting terminal.

[0088] Furthermore, it also includes a link prediction module, which is used to preprocess the source data according to the communication requirements of the destination before the data processing module processes the source data.

[0089] In the above scheme, the sensor module further includes a motion sensor, which is used to collect information on whether the user terminal is moving; when the user terminal moves, the communication requirement information includes control information for adjusting the beamwidth of the light source.

[0090] Furthermore, the sensor module also includes an image sensor, which is used to collect information on whether the receiver lacks a light source link; when the receiver lacks a light source link, the communication requirement information includes control information for adjusting the light source beamwidth.

[0091] Furthermore, the signal pre-recovery module is equipped with a memory, in which the location information of the user terminal and the associated channel state information are locally stored; wherein, the storage strategy of the channel state information in the memory includes channel state information estimated using the direct component LOS, and channel state information estimated using the direct and reflected components NLOS.

[0092] An indoor optical communication method includes the following steps:

[0093] The source generates the source signal;

[0094] The source signal is preprocessed according to the communication requirements of the destination;

[0095] The preprocessed source signal is modulated to obtain the modulated signal;

[0096] The light source converts the modulation signal into an optical signal and transmits it through a MIMO channel;

[0097] Receive optical signals within the MIMO channel and convert them into electrical signals;

[0098] The electrical signal is recovered using channel state information. Specifically, when the user terminal's location information is stored locally, the electrical signal is recovered using the locally stored channel state information associated with that location information. When the user terminal's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the electrical signal is recovered using the obtained channel state information, which is then stored locally. The MIMO channel model is associated with the location information of the light source and the user terminal.

[0099] The demodulated and recovered electrical signal is sent to the sink.

[0100] An indoor optical communication method includes the following steps:

[0101] The source generates the source signal;

[0102] The source signal is preprocessed according to the communication requirements of the destination;

[0103] The preprocessed source signal is modulated to obtain the modulated signal;

[0104] The modulation signal is pre-recovered using channel state information, wherein when the user's location information is stored locally, the modulation signal is pre-recovered using the locally stored channel state information associated with that location information; when the user's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the obtained channel state information is used to pre-recover the modulation signal, and the obtained channel state information is stored locally; wherein the MIMO channel model is associated with the location information of the light source and the location information of the user.

[0105] The light source converts the pre-recovered modulation signal into an optical signal and transmits it through a MIMO channel;

[0106] Receive optical signals within the MIMO channel and convert them into electrical signals;

[0107] The demodulated and recovered electrical signal is sent to the sink.

[0108] To better understand the working principles of the transmitting and receiving terminals based on optical communication and the working method of optical communication in this invention, this invention provides... Figure 1 and Figure 2 The two indoor MIMO-VLC communication systems shown are described in detail.

[0109] Example 1

[0110] Reference Figure 1 The indoor MIMO-VLC communication system shown includes: an intelligent transmitting module, which comprises a signal source, a link prediction module, a transmitting-end data processing module, an electro-optic driving module, and multiple light sources; wherein, the signal source generates a signal of random bits and transmits the signal to the link prediction module, which is used to determine whether all light sources have LOS components reaching the intelligent receiving module and to determine the number of MIMO outputs; the link prediction module has two input ports, which respectively receive the signal from the signal source and the control information for expressing the sink requirements transmitted by the intelligent receiving module (i.e., the user end) through the feedback link, as well as the control information of the image sensor; after the signal passes through the link prediction module, information on the beamwidth of the control light source and the number of MIMO splitters is added; then the link prediction module sends the processed signal to the transmitting-end data processing module, where the information is converted from serial to parallel, mapped, and modulated to generate multiple light source driving signals; finally, the generated signals are transmitted to the electro-optic driving module in the form of control signals; the electro-optic driving module drives the light sources to emit light; at the same time, the light sources are controlled by the electro-optic driving module to adjust their orientation and change the width of the emitted light waves;

[0111] The intelligent receiving module includes a photoelectric detection module, a signal recovery module, a receiving-end data processing module, and a sink. The photoelectric detection module consists of multiple photodetectors, which can convert the optical signal emitted by the light source signal in the MIMO channel into an electrical signal and send the electrical signal to the signal recovery module for signal recovery. After recovery, the signal is demodulated, de-mapped, and converted from parallel to serial by the receiving-end data processing module before being transmitted to the sink. The sink, as a communication terminal, sends control information to the link prediction module through the feedback link when it needs a communication link.

[0112] After the signal recovery module receives the electrical signal converted by the photodetector, it first checks the local storage module to determine if the channel state information for this location has already been stored. If it has, the module directly uses the stored channel state information to recover the signal. If not, the module obtains the user's location through the sensor module, then establishes a MIMO channel model to obtain the channel state information. This information is used to distinguish and recover the electrical signal converted by the photodetector, and the channel state information for this location is stored locally. This invention provides two channel state information storage strategies: Scheme 1: Only store channel information estimated using the direct light component (LOS). Scheme 2: Store channel information estimated using both direct and reflected light components (NLOS). The recovered signal will then be transmitted to the data processing module.

[0113] The indoor optical channel includes a MIMO channel from the source to the destination and a feedback link from the destination to the link pre-decision module;

[0114] The sensor module includes a positioning sensor, a motion sensor, and an image sensor. The positioning sensor acquires the location information from the intelligent receiving module and sends the result to the signal recovery module to achieve signal recovery. The motion sensor determines whether the user has moved, thereby controlling the image sensor to operate and sending the result to the link prediction module via a feedback link to adjust the width of the light source's emission beam.

[0115] In one embodiment of the present invention, the signal recovery module has an embedded storage module and has two inputs, which respectively receive the electrical signal obtained after being converted by the photodetector and the user location information transmitted by the positioning sensor.

[0116] In one embodiment of the present invention, the communication method of the indoor MIMO-VLC communication system is as follows:

[0117] Step 1: The information source generates information, which is recorded as the source signal, and this information is transmitted to the link prediction module;

[0118] Step Two: The link prediction module predicts the communication scenario, determines the link status of each light source, adjusts the light source beamwidth, and determines the number of multiple inputs for MIMO. The primary objective is to address the coverage issue in indoor mobile communication, requiring light sources to adjust their beamwidth (half-power angle) to achieve reliable communication at various locations. For example, when the intelligent receiver module moves to a corner of the house, the farthest light source may not receive LOS components, resulting in lower received power. Therefore, it's necessary to change the light source beamwidth to expand its coverage. Using a Lambertian source as an example, this involves adjusting the Lambertian order m to be smaller.

[0119] The specific steps of this process are as follows: In the intelligent receiving module, when the motion sensor detects user movement, it needs to control the lens to take a picture and determine whether each light source has a LOS component reaching the intelligent receiving module. If a missing light source link is detected, control information is sent through the feedback link to control the light source to adjust its beamwidth to achieve reliable communication. However, adjusting the beamwidth will reduce the receiving power of the photodetector per unit area, so the power of the light needs to be increased to meet communication requirements. Therefore, the reason why a fixed, wider beamwidth is not used indoors to achieve full communication coverage is that a narrower beamwidth can meet communication requirements in the central area of ​​the house (the area with active communication), thus saving more energy.

[0120] The second objective is to achieve multiple outputs for the system. The intelligent receiving module determines the specific grouping information based on the number of light sources and feeds it back to the link prediction module, which determines the subsequent steps of the signal conversion from serial to parallel. In general, after the signal passes through the link prediction module, information on the beamwidth of the control light source and the number of MIMO splitters will be added.

[0121] Step 3: Signal Transmission. The link prediction module sends the processed signal to the transmitting data processing module. In the transmitting data processing module, the information undergoes serial-to-parallel conversion, mapping, and modulation to generate multiple light source drive signals. After entering the electro-optic drive module, the signals are transmitted by the light source. Let the optical signal transmitted by the light source be x. i (t), x i (t) is the time-domain representation of the original signal from the i-th light source (where 1 ≤ i ≤ M, and M is the number of light sources). Furthermore, for easier signal processing, let X be... i (f) represents x i The frequency domain transfer function of (t);

[0122] Step 4: Signal reception. The photoelectric detection module of the intelligent receiver module receives multiple light source optical signals in the MIMO channel; this process can be represented by the time-domain convolution relationship between the transmitted signal, the channel impulse response, and the received signal:

[0123]

[0124] Where γ is the photodetector responsivity, y j (t) is the time-domain representation of the received signal, where j represents the j-th photodetector, where 1 ≤ j ≤ N, h total,ji It is the impulse response of the channel between the i-th light source and the j-th photodetector, ⊙ represents the convolution operation, and n(t) is additive Gaussian noise; Equation (1) is complex in the time domain, and the signal y(t) received by the intelligent receiving module is Therefore, very accurate channel state information is needed to recover x. i(t);

[0125] Step 5: Establish signal model / query local storage table; After the photoelectric detection module of the intelligent receiving module receives the signal, it directly obtains the channel state information by establishing a signal model. The specific steps are: the positioning sensor obtains the location information of the intelligent receiving module, then the MIMO channel model is established, and the channel state information is solved.

[0126] Since the indoor optical channel is a constant parameter channel, the position of the photoelectric detection module is obtained by the positioning sensor. The light source is on the ceiling of the house and its position is fixed. The channel is modeled by the illumination model.

[0127] Let the position coordinates of the photodetector be (R) j :(a rj ,b rj ,c rj (where 1≤j≤N), the position coordinates of the light source (T) i :(a ti ,b ti ,c ti ), where 1≤i≤M is known;

[0128] Assuming the light source is a Lambertian source, the impulse response h of the channel between the i-th light source and the j-th photodetector can be calculated using formula (2). total,ji :

[0129]

[0130] Among them, T i Let R be the three-dimensional position coordinates of the i-th light source. j Let be the three-dimensional position coordinates of the j-th photodetector, α be the angle between the projection of the receiving terminal's orientation onto the XY plane and the x-axis, β be the angle between the receiving terminal's orientation and the z-axis, and Φ be the angle between the receiving terminal's orientation and the z-axis. 1 / 2 It is the half-power angle of the light source (i.e., the beamwidth of the light source); τ los,ji It is the time delay of the direct optical link (LOS), τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji (τ nlos,ji The specific delay τ under the NLOS link is... nlos,ji The channel DC gain corresponding to the component. Since there are infinitely many reflective elements indoors, the time delay values ​​of the reflected signal components are also infinitely many, with infinitesimal intervals, so differentiation is required;

[0131] After obtaining equation (2), we use equation (2) to represent the state information of the MIMO channel. Using equations (1) and (2), we can derive that the time-domain matrix form of the MIMO channel can be expressed as:

[0132]

[0133] From (2) to (3) is the process from SISO to MIMO;

[0134] The Fourier transform of equation (1) yields its frequency domain form, which is then expressed in matrix form:

[0135] Y(f)=γH total (f)×X(f)+N(f), (4)

[0136] Y(f) = [Y1(f), Y2(f), ..., Y R (f)] T X(f) = [X1(f), X2(f), ... X T (f)] T Where Y j (f) and X i (f) is y j (t) and x i The frequency domain transfer function of (t), H total (f) is h total (f) is the frequency domain transfer function, where × represents multiplication, and N(f) is the frequency domain transfer function of n(t). Using location information, the time-domain and frequency-domain information of the MIMO channel is obtained, and a quantitative relationship between the transmitted signal, received signal, and channel is established. When the intelligent receiving module communicates for the first time at a certain location, the aforementioned channel establishment process is performed to obtain the channel state information for that location, and then the channel state information for that location is stored locally. When communicating again at the same location, the channel establishment step is skipped by browsing the locally stored table, and the channel state information is obtained directly from the table.

[0137] Step Six: Signal Recovery. The signal recovery module obtains channel state information and multiple light source signals, and recovers the original light source signal using the channel state information. The frequency domain change process can be represented as:

[0138]

[0139] Where T total (f) is H total The inverse of (f):

[0140]

[0141] Finally, after the inverse Fourier transform, x can be obtained. i (t);

[0142] Step 7: Recover the original light source signal x i (t) After passing through the digital processing module, it is demodulated, de-mapped, and converted from parallel to serial to the source signal.

[0143] Example 2

[0144] like Figure 2 (a) shows an indoor MIMO-VLC communication system, comprising: an intelligent transmitting module, which includes a signal source, a link prediction module, a transmitting-end data processing module, a signal pre-recovery module, an electro-optical driving module, and multiple light sources; the signal source generates a signal of random bits and transmits the signal to the link prediction module, which is used to determine whether all light sources have LOS components reaching the intelligent receiving module and to determine the number of multiple outputs of the MIMO; the link prediction module has two input ports, which respectively receive the signal from the signal source and the control information for expressing the sink requirements transmitted by the intelligent receiving module through the feedback link, as well as the control information of the image sensor; the signal passes through the link prediction module and is added with information on the beamwidth of the control light source and the number of MIMO splitters; then the link prediction module sends the processed signal to the transmitting-end data processing module, where the information is converted from serial to parallel, mapped, and modulated to generate multiple light source driving signals; the signal pre-recovery module receives the information from the transmitting-end data processing module; finally, the recovered signal is transmitted to the electro-optical driving module in the form of a control signal; the electro-optical driving module drives the light source to emit light; at the same time, the light source is controlled by the electro-optical driving module to adjust its orientation and change the width of the emitted light wave.

[0145] The signal pre-recovery module is designed to overcome the unavoidable noise amplification problem during signal recovery in MIMO systems. It uses channel state information in the intelligent transmitter module to pre-recover the signal, simplifying signal recovery in the intelligent receiver module and preventing noise amplification, thus reducing the bit error rate. The signal pre-recovery module has two inputs: the data to be transmitted, processed by the transmitter data processing module (serial-to-parallel conversion, mapping, and modulation), and the location information sent by the positioning sensor. Its role in communication is the same as the signal recovery module. After obtaining the location information from the intelligent receiver module, it first checks the local storage module to determine if the channel state information for this location has already been stored. If it has, the stored channel state information is used directly for signal pre-recovery. If not, a MIMO channel model is built using the location information to obtain the channel state information, pre-recover the signal, and then the channel state information for this location is stored locally. This local storage provides two strategies: Scheme 1: Only store the channel information estimated using the direct (LOS) component. Scheme 2: Store the channel information estimated using both direct and reflected (NLOS) components. The pre-recovered signal is then sent to the light source for transmission.

[0146] The intelligent receiving module includes a photoelectric detection module, a receiving data processing module, and a sink. The photoelectric detection module consists of multiple photoelectric detectors, which can convert the optical signal emitted by the light source signal in the MIMO channel into an electrical signal. The electrical signal is then demodulated, de-mapped, and converted from parallel to serial by the receiving data processing module before being transmitted to the sink. The sink, as a communication terminal, sends control information to the link prediction module through the feedback link when it needs a communication link.

[0147] The indoor optical channel includes a MIMO channel from the source to the destination and a feedback link from the destination to the link pre-decision module. In this embodiment, a feedback link is added between the signal pre-recovery module and the positioning sensor. The positioning sensor intelligently receives the location message from the module through the feedback link and transmits it to the signal pre-recovery module.

[0148] The sensor module includes a positioning sensor, a motion sensor, and an image sensor. The positioning sensor is used to acquire the location information from the intelligent receiving module. The motion sensor is used to determine whether the user is moving, thereby controlling the image sensor to work and sending the result to the link prediction module through the feedback link so as to adjust the width of the emitted beam of the light source.

[0149] This communication system is more suitable for application in MIMO communication. As can be seen from formula (5), there is an amplified noise term in the frequency domain of the solved signal. This term inevitably brings a higher bit error rate to the signal. Therefore, in the position of poor signal-to-noise ratio, a higher bit error rate can only be obtained by a higher signal-to-noise ratio. In this embodiment, the addition of a signal pre-recovery module to the intelligent transmission module effectively solves this problem.

[0150] like Figure 2 As shown in (b), the positioning sensor is directly installed in the intelligent transmitting module; the positioning sensor directly sends the position information of the intelligent receiving module to the signal pre-recovery module.

[0151] The specific communication method of the indoor MIMO-VLC communication system based on the above structure is as follows:

[0152] Step 1: The information source generates information, which is recorded as the source signal, and this information is transmitted to the link prediction module;

[0153] Step 2: The link prediction module predicts the communication scenario, determines the link status of each light source, changes the light source beamwidth, and determines the number of multiple inputs for MIMO.

[0154] Step 3: The signal pre-recovery module receives the location information of the intelligent receiving module sent by the positioning sensor in the feedback channel, or the positioning sensor of the intelligent transmitting module directly locates the intelligent receiving module to obtain the location information of the intelligent receiving module;

[0155] The channel state information is obtained through either the channel model establishment process or a local table query; the specific process is as follows:

[0156] The position of the photoelectric detection module is obtained by a positioning sensor. The light source is located on the ceiling of the house and its position is fixed. The channel is modeled by a lighting model.

[0157] Let the position coordinates of the photodetector be (R) j :(a rj ,b rj ,c rj (where 1≤j≤N), the position coordinates of the light source (T) i :(a ti ,b ti ,c ti (where 1≤i≤M) is known;

[0158] Assuming the light source is a Lambertian source, the impulse response h of the channel between the i-th light source and the j-th photodetector can be calculated using formula (2). total,ji :

[0159]

[0160] Among them, T i Let R be the three-dimensional position coordinates of the i-th light source. j Let be the three-dimensional position coordinates of the j-th photodetector, α be the angle between the projection of the receiving terminal's orientation onto the XY plane and the x-axis, β be the angle between the receiving terminal's orientation and the z-axis, and Φ be the angle between the receiving terminal's orientation and the z-axis. 1 / 2 It is the half-power angle of the light source (i.e., the beamwidth of the light source); τ los,ji It is the time delay of the direct optical link (LOS), τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji (τ nlos,ji The specific delay τ under the NLOS link is... nlos,ji The channel DC gain corresponding to the component of the reflected signal is determined by the fact that there are infinitely many reflective elements indoors, so the time delay of the reflected signal component also has infinitely many values ​​with infinitesimal intervals, so differentiation is required.

[0161] After obtaining equation (2), we use equation (2) to represent the state information of the MIMO channel. Using equations (1) and (2), we can derive that the time-domain matrix form of the MIMO channel can be expressed as:

[0162]

[0163] An additional signal pre-recovery process is added, i.e., the frequency domain of the generated signal is X.pre The signal of (f):

[0164] X pre (f)=T total (f)×X(f), (7)

[0165] Step 4: The pre-recovered X pre (f) The signal is sent into the MIMO channel and obtained

[0166]

[0167] It can be seen that the noise term in (8) is not amplified. Through simple decision-making and inverse Fourier transform, x can be obtained. i (t).

[0168] Step 5: Recover the original light source signal x i (t) After passing through the receiving end digital processing module, it is demodulated, de-mapped, and converted from parallel to serial to the source signal.

[0169] To evaluate the performance of the above scheme in MIMO-VLC, taking the communication system in Example 1 as an example, a specific 2×2 MIMO indoor communication scenario was set up, with an indoor size of 5m×5m×3m (length×width×height). LED lights were used as the light source, and PD (photodetector) was used. The LED lights were deployed on the ceiling, each with a power of 20W and a modulation index of 0.2. The coordinates of LED1 were (1.5, 1.5, 3), LED2 (1.5, 3.5, 3), LED3 (3.5, 1.5, 3), and LED4 (3.5, 3.5, 3). LED1 and LED4 transmitted one set of independent signals as group 1, while LED2 and LED3 transmitted another set of independent signals as group 2. The purpose of using four lights was to provide uniform illumination distribution. The intelligent receiving modules are located near indoor corners (PD1 coordinates: (0.5, 0.5, 0.85), PD2 coordinates: (0.5, 0.6, 0.85)) and near the center of the room (PD1 coordinates: (3.3, 2.55, 0.85), PD2 coordinates: (3.3, 2.65, 0.85)). The photoelectric conversion coefficient of the PDs is 0.35 A / W. After mapping, the signal is modulated using OOK and enters a 2×2 MIMO channel, with a single-lamp symbol rate of 100 Mb and a total system symbol rate of 200 Mb. The optical link only considers direct light and single reflection cases.

[0170] This experiment provides simulations for three different schemes.

[0171] Scheme 1 uses only the LOS component to obtain channel state information for signal recovery.

[0172] Scheme 2 considers LOS and NLOS components to obtain channel state information for signal recovery, while the training sequence scheme uses training sequences to estimate the channel and recover information. The channel state information obtained through long training sequences is the true channel state information.

[0173] Figure 3 The channel frequency domain transfer function from LED group 1 to PD1 is shown at two different locations. The results demonstrate that both LOS and NLOS channel modeling schemes can completely estimate the MIMO channel state information at different locations. The channel modeling scheme considering only the LOS link can estimate the channel information more accurately in the center of the room than in the corners.

[0174] To more accurately demonstrate the performance of the solution, the bit error rate in various areas of a real indoor environment was simulated, such as... Figure 4 As shown in the figure, approximately 24% of the way from the center of the building, the channel modeling scheme of Scheme 1 can be used to store channel state information, resulting in a recovered signal bit error rate of less than 3.8 × 10⁻⁶. -3 (This bit error rate can be considered the maximum bit error rate for error-free signal recovery), because in the center of the room, the reflected light component is smaller, and the energy proportion of LOS is larger. However, at the edges of the room and near the corners, the channel modeling scheme of Scheme 2 can be used to store channel state information. Its maximum bit error rate range for error-free signal recovery accounts for 73% of the total indoor area. The remaining portion cannot communicate due to signal-to-noise ratio limitations, requiring the use of more powerful LEDs for communication. This example shows that in the 24% area in the center of the room, only the LOS component information of the MIMO channel can be stored, while at the edges and corners, both the LOS and NLOS component information of the MIMO channel need to be stored.

[0175] Furthermore, to explore the advantages of signal pre-recovery schemes in MIMO communication, simulations were performed on the bit error rate and signal-to-noise ratio changes of various schemes at the corners (PD1 coordinates: (0.5, 0.5, 0.85) and PD2 coordinates: (0.5, 0.6, 0.85)). Figure 5 As can be seen, at the corners, Scheme 1 requires a higher signal-to-noise ratio to recover the signal without errors. The bit error rate performance of Scheme 2 and the training sequence scheme is almost identical.

[0176] As shown in equations (5) and (8), noise amplification is unavoidable when the intelligent receiving module recovers the signal. Figure 5 It can also be seen that Scheme 2 requires a higher signal-to-noise ratio than the pre-recovery scheme to achieve the same bit error rate performance. Therefore, the pre-recovery scheme used in the communication system of Example 2 has great application value in improving bit error rate performance.

[0177] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0178] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0179] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0180] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0181] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A receiving terminal based on optical communication, characterized in that: include: The photoelectric detection module receives optical signals from the MIMO channel and converts them into electrical signals. The photoelectric detection module contains multiple photodetectors, each of which receives different optical signals. After the optical signals are converted into electrical signals, they are all recovered by a signal recovery module. The sensor module includes a positioning sensor for collecting location information from the user terminal. A signal recovery module is used to recover the electrical signal using locally stored channel state information after acquiring the location information of the user terminal; Alternatively, channel state information can be obtained by establishing a MIMO channel model and then used to recover the electrical signal. Specifically, when the user's location information is stored locally, the locally stored channel state information associated with that location information is used to recover the electrical signal; when the user's location information is not stored locally, the MIMO channel model is established, the channel state information is obtained, and the obtained channel state information is stored locally. The MIMO channel model is associated with the user's location information. The data processing module is used to process the electrical signal recovered by the signal recovery module to obtain the source signal; The receiver receives the source signal and sends communication request information; The user-end location information includes the position coordinates of the light source, the position coordinates of the photodetector, the orientation of the photodetector, and the beamwidth of the light source; this information is transmitted via the channel's impulse response. h total,ji The channel state information is obtained; where h total,ji The formula is as follows: ； in, T i For the first i The three-dimensional position coordinates of each light source R j For the first j The three-dimensional position coordinates of each photodetector α For the projection of the receiving terminal onto the XY plane and x The included angle of the axis, β Orientation of the receiving terminal and z The included angle of the axis, Φ 1 / 2 It is the half-power angle of the light source; τ los,ji It is the time delay of the direct optical link (LOS). τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji ( τ nlos,ji The specific latency under an NLOS link is... τ nlos,ji The channel DC gain corresponding to the component, H los,ji (0) and A nlos,ji ( τ nlos,ji Both are functions of position coordinates, and are calculated using the position coordinates of the photodetector and the light source, the orientation angle of the photodetector, and the half-power angle of the light source, respectively. When recovering the signal at the receiving terminal, in addition to obtaining the position coordinates and orientation angle of the photodetector from the sensor module, it is still necessary to obtain the half-power angle of the light source through the communication link. When performing signal pre-recovery at the transmitting terminal, it is only necessary to obtain the position coordinates and orientation angle of the photodetector from the sensor module.

2. The optical communication-based receiving terminal according to claim 1, characterized in that: The positioning sensor can be set up independently or integrated with the receiving terminal.

3. The receiving terminal based on optical communication according to claim 2, characterized in that: The sensor module also includes a motion sensor and an image sensor. The motion sensor is used to collect information on whether the user terminal is moving. When the user terminal moves, the communication request information includes control information for adjusting the beamwidth of the light source. The image sensor is used to collect information on whether the photoelectric detection module lacks a light source link. When the photoelectric detection module lacks a light source link, the communication requirement information includes control information for adjusting the light source beamwidth.

4. The receiving terminal based on optical communication according to claim 1, characterized in that: The signal recovery module includes a memory where the user's location information and the associated channel state information are stored locally. The storage strategy for the channel state information in the memory includes channel state information estimated using the direct component LOS and channel state information estimated using both direct and reflected components NLOS.

5. A transmitting terminal based on optical communication, characterized in that: include, A signal source is used to generate a source signal; A data processing module is used to process the source signal to obtain a modulated signal; The sensor module includes a positioning sensor for collecting location information from the user terminal. A signal pre-recovery module is provided, which is used to pre-recover the modulated signal using locally stored channel state information after acquiring the user's location information; or to obtain channel state information by establishing a MIMO channel model and using the channel state information to pre-recover the modulated signal; wherein, when the user's location information is stored locally, the locally stored channel state information associated with the location information is used to pre-recover the modulated signal; when the user's location information is not stored locally, the MIMO channel model is established, the channel state information is obtained, and the obtained channel state information is stored locally; wherein, the MIMO channel model is associated with the user's location information; An electro-optical driving module is used to drive a light source to emit light and can control and change the beamwidth of the light source. The light source is used to convert the modulated signal processed by the signal pre-recovery module into an optical signal and send it out; the light source includes multiple light sources, which are simultaneously driven by the electro-optic driving module, and the multiple light sources emit different signals at the same time, which are then processed by the MIMO channel to form a MIMO signal; The user-end location information includes the position coordinates of the light source, the position coordinates of the photodetector, the orientation of the photodetector, and the beamwidth of the light source; this information is transmitted via the channel's impulse response. h total,ji The channel state information is obtained; where h total,ji The formula is as follows: ； in, T i For the first i The three-dimensional position coordinates of each light source R j For the first j The three-dimensional position coordinates of each photodetector α For the projection of the receiving terminal onto the XY plane and x The included angle of the axis, β Orientation of the receiving terminal and z The included angle of the axis, Φ 1 / 2 It is the half-power angle of the light source; τ los,ji It is the time delay of the direct optical link (LOS). τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji ( τ nlos,ji The specific latency under an NLOS link is... τ nlos,ji The channel DC gain corresponding to the component, H los,ji (0) and A nlos,ji ( τ nlos,ji Both are functions of position coordinates, and are calculated using the position coordinates of the photodetector and the light source, the orientation angle of the photodetector, and the half-power angle of the light source, respectively. When recovering the signal at the receiving terminal, in addition to obtaining the position coordinates and orientation angle of the photodetector from the sensor module, it is still necessary to obtain the half-power angle of the light source through the communication link. When performing signal pre-recovery at the transmitting terminal, it is only necessary to obtain the position coordinates and orientation angle of the photodetector from the sensor module.

6. The optical communication-based transmitting terminal according to claim 5, characterized in that: The positioning sensor can be set up independently or integrated with the transmitting terminal.

7. The optical communication-based transmitting terminal according to claim 5, characterized in that: It also includes a link prediction module, which is used to preprocess the source data according to the communication requirements of the destination before the data processing module processes the source data.

8. The optical communication-based transmitting terminal according to claim 7, characterized in that: The sensor module further includes a motion sensor and an image sensor. The motion sensor is used to collect information on whether the user terminal is moving. When the user terminal moves, the communication requirement information includes control information for adjusting the beamwidth of the light source. The image sensor is used to collect information on whether the receiving end lacks a light source link. When the receiving end lacks a light source link, the communication requirement information includes control information for adjusting the beamwidth of the light source.

9. The optical communication-based transmitting terminal according to claim 5, characterized in that: The signal pre-recovery module includes a memory where the location information of the user terminal and the associated channel state information are stored locally. The storage strategy for the channel state information in the memory includes channel state information estimated using the direct component LOS and channel state information estimated using the direct and reflected components NLOS.

10. An indoor optical communication method, characterized in that: Includes the following steps, The source generates the source signal; The source signal is preprocessed according to the communication requirements of the destination; The preprocessed source signal is modulated to obtain the modulated signal; The light source converts the modulation signal into an optical signal and transmits it through a MIMO channel; Receive optical signals within the MIMO channel and convert them into electrical signals; The electrical signal is recovered using channel state information. Specifically, when the user's location information is stored locally, the electrical signal is recovered using the locally stored channel state information associated with that location information. When the user's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the electrical signal is recovered using the obtained channel state information, which is then stored locally. The MIMO channel model is associated with the location information of the light source and the user's location information. The demodulated and recovered electrical signal is sent to the sink. The user-side location information includes the location coordinates of the light source, the location coordinates of the photodetector, the orientation of the photodetector, and the beamwidth of the light source; this information is transmitted via the channel's impulse response. h total,ji The channel state information is obtained; where h total,ji The formula is as follows: ； in, T i For the first i The three-dimensional position coordinates of each light source R j For the first j The three-dimensional position coordinates of each photodetector α For the projection of the receiving terminal onto the XY plane and x The included angle of the axis, β Orientation of the receiving terminal and z The included angle of the axis, Φ 1 / 2 It is the half-power angle of the light source; τ los,ji It is the time delay of the direct optical link (LOS). τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji ( τ nlos,ji The specific latency under an NLOS link is... τ nlos,ji The channel DC gain corresponding to the component, H los,ji (0) and A nlos,ji ( τ nlos,ji Both are functions of position coordinates, and are calculated using the position coordinates of the photodetector and the light source, the orientation angle of the photodetector, and the half-power angle of the light source, respectively. When recovering the signal at the receiving terminal, in addition to obtaining the position coordinates and orientation angle of the photodetector from the sensor module, it is still necessary to obtain the half-power angle of the light source through the communication link. When performing signal pre-recovery at the transmitting terminal, it is only necessary to obtain the position coordinates and orientation angle of the photodetector from the sensor module.

11. An indoor optical communication method, characterized in that: Includes the following steps, The source generates the source signal; The source signal is preprocessed according to the communication requirements of the destination; The preprocessed source signal is modulated to obtain the modulated signal; The modulation signal is pre-recovered using channel state information, wherein when the user's location information is stored locally, the modulation signal is pre-recovered using the locally stored channel state information associated with that location information; when the user's location information is not stored locally, the channel state information is obtained by establishing a MIMO channel model, and the obtained channel state information is used to pre-recover the modulation signal, and the obtained channel state information is stored locally; wherein the MIMO channel model is associated with the location information of the light source and the location information of the user. The light source converts the pre-recovered modulation signal into an optical signal and transmits it through a MIMO channel; Receive optical signals within the MIMO channel and convert them into electrical signals; The demodulated and recovered electrical signal is sent to the sink. The user-end location information includes the position coordinates of the light source, the position coordinates of the photodetector, the orientation of the photodetector, and the beamwidth of the light source; this information is transmitted via the channel's impulse response. h total,ji The channel state information is obtained; where h total,ji The formula is as follows: ； in, T i For the first i The three-dimensional position coordinates of each light source R j For the first j The three-dimensional position coordinates of each photodetector α For the projection of the receiving terminal onto the XY plane and x The included angle of the axis, β Orientation of the receiving terminal and z The included angle of the axis, Φ 1 / 2 It is the half-power angle of the light source; τ los,ji It is the time delay of the direct optical link (LOS). τ nlos,ji It is the time delay of the light reflection link (NLOS); H los,ji (0) is the channel DC gain under the LOS link, A nlos,ji ( τ nlos,ji The specific latency under an NLOS link is... τ nlos,ji The channel DC gain corresponding to the component, H los,ji (0) and A nlos,ji ( τ nlos,ji Both are functions of position coordinates, and are calculated using the position coordinates of the photodetector and the light source, the orientation angle of the photodetector, and the half-power angle of the light source, respectively. When recovering the signal at the receiving terminal, in addition to obtaining the position coordinates and orientation angle of the photodetector from the sensor module, it is still necessary to obtain the half-power angle of the light source through the communication link. When performing signal pre-recovery at the transmitting terminal, it is only necessary to obtain the position coordinates and orientation angle of the photodetector from the sensor module.

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