Indoor high-speed visible light communication and positioning integrated method and device

Abstract

The application discloses an indoor high-speed visible light communication and positioning integrated method and device, which comprises the following steps: acquiring the coordinates of four LED lighting lamps at the four corners of the roof of a rectangular indoor space, wherein the four LED lighting lamps serve as signal transmitting ends; loading transmission signals on the signal transmitting ends; the signal transmitting ends generate constant envelope orthogonal frequency division multiplexing signals by performing signal processing on the transmission signals based on the constant envelope orthogonal frequency division multiplexing technology, and the signal envelopes of the processed signals are always sinusoidal functions; the signal receiving ends perform signal processing on the signals processed by the signal transmitting ends in the opposite direction of the signal transmitting ends and output the processed signals, thereby realizing indoor high-speed visible light communication; and the coordinates of photodetectors are calculated according to the acquired coordinates of the four LED lighting lamps, thereby realizing indoor high-speed visible light positioning. The application can improve the communication rate while the LED lighting lamps complete the lighting function, realize indoor high-speed visible light communication and complete the positioning of the receiving end.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of visible light communication, and particularly relates to an indoor high-speed visible light communication and positioning integrated method and device. BACKGROUND

[0002] The indoor visible light communication technology can be applied to daily office work and secret communication, and has the outstanding characteristics of fast transmission rate and high communication security degree. The application of the visible light communication technology in the lighting field realizes the indoor visible light communication system, and the research in this aspect is valued with the large-scale application of the white light illumination light emitting diode (LED). Another important factor for the birth of the indoor visible light communication technology is that with the development of information technology, human beings enter the mobile internet era, and more and more wireless communication services have an explosive growth in demand for bandwidth. The existing wireless spectrum resources are limited and most of them have been allocated, which leads to the continuous expansion of the gap of the spectrum resources. Although the effective spectrum management and dynamic spectrum access and the like can solve the problem of the spectrum resource shortage to a certain extent, the problem still exists. At the same time, the visible light communication also has some disadvantages. The white light illumination LED has a small bandwidth, and the original design is used for illumination, which makes the general modulation method unable to realize high-speed communication. The ordinary orthogonal frequency division multiplexing (OFDM) technology can improve the spectrum efficiency to a certain extent, but the high peak-to-average power ratio (PAPR) will cause the problems of the non-linear effect of the LED and the large power consumption, and therefore the precise positioning of the indoor receiving end and the simultaneous realization of the communication and the positioning cannot be realized. SUMMARY

[0003] The application aims to solve the technical problem of providing an indoor high-speed visible light communication and positioning integrated method and device, and solve the problems of the limited bandwidth of the LED as a light source of the light fidelity (LiFi) and the simultaneous realization of the communication and the positioning.

[0004] To solve the above technical problems, the application realizes the following technical scheme:

[0005] An indoor high-speed visible light communication and positioning integrated method, specifically comprising the following steps:

[0006] Step 1, obtaining the coordinates of four LED illumination lamps at four corners of the roof of a rectangular indoor space, and the four LED illumination lamps serving as a signal transmitting end;

[0007] Step 2, loading a transmission signal on the signal transmitting end;

[0008]

[0008] Step 3, the signal transmitting end generates a constant envelope orthogonal frequency division multiplexing signal by performing signal processing on the transmission signal based on the constant envelope orthogonal frequency division multiplexing technology, and the signal envelope after the processing is always a sine function;

[0009] Step 4, the photoelectric detector movable on the ground of the rectangular indoor space receives the processed signal of the signal transmitting end as the signal receiving end;

[0010] Step 5, the signal receiving end performs the signal processing opposite to that of the signal transmitting end on the processed signal of the signal transmitting end and outputs, realizing the indoor high-speed visible light communication.

[0011] Step 6, the coordinates of the photoelectric detector are calculated according to the coordinates of the four LED lighting lamps obtained in Step 1, realizing the indoor high-speed visible light positioning.

[0012] The large divergence angle of the four LED lighting lamps makes them irradiate all positions of the ground of the rectangular indoor space, meanwhile, the four LED lighting lamps serve as the signal transmitting end and the photoelectric detector movable on the ground of the rectangular indoor space serves as the signal receiving end to receive the signals of the four LED lighting lamps respectively. The envelope of the constant envelope orthogonal frequency division multiplexing signal generated by the signal transmitting end after processing the signal is always in the form of sinusoidal signal. By using this feature, the LED of the signal transmitting end loads the same envelope of the ordinary signal in the color dimension except the color dimension of the signal, so that the LED can use white light for illumination while loading the transmission signal in one dimension, realizing the indoor high-speed visible light communication, and the coordinates of the photoelectric detector can be obtained by acquiring the coordinates of the four LED lighting lamps, realizing the indoor visible light positioning.

[0013] Preferably, the four LED lighting lamps adopt RGBA four-dimensional color space, the four LED lighting lamps use one dimension in the RGBA color space to modulate and load the signal respectively, and the photoelectric detector is provided with RGBA four-dimensional filter, which can receive and process the signal of the corresponding color dimension, realizing the indoor high-speed visible light communication.

[0014] Preferably, the signal processing of the signal transmitting end to generate the constant envelope orthogonal frequency division multiplexing signal based on the constant envelope orthogonal frequency division multiplexing technology specifically includes: the signal transmitting end sequentially performs serial-parallel conversion, QAM mapping, N-point DFT extension, subcarrier allocation, 2N-point DFT extension, real / imaginary part connection and parallel-serial conversion processing to generate the constant envelope orthogonal frequency division multiplexing signal. After the above processing, the envelope of the generated constant envelope orthogonal frequency division multiplexing signal is always in the form of sinusoidal signal.

[0015] Preferably, the step 5, the signal receiving end processes the signal processed by the signal transmitting end and outputs in reverse to the signal processing of the signal transmitting end, specifically including: the signal receiving end processes the signal processed by the signal transmitting end in sequence and performs parallel-to-serial conversion, real / imaginary part connection, inverse symmetric mapping, 2N-point DFT transformation, frequency domain equalization, subcarrier inverse allocation, N-point IDFT expansion, QAM inverse mapping and parallel-to-serial conversion processing and outputs, finally realizing indoor high-speed visible light communication.

[0016] Preferably, since the constant envelope orthogonal frequency division multiplexing signal generated by the signal processing process of the signal transmitting end has a constant envelope in the form of a sinusoidal signal, the signal is sensitive to distance information, and the transmission distance of the signal can be determined by receiving the signal, therefore, when the signal receiving end receives the signals transmitted by the four LEDs of the signal transmitting end, the transmission distances of the four signals can be obtained, specifically as follows, the coordinates of the four LED lighting lamps obtained in step 1 are (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), (x4, y4, z4), if the coordinates of the photodetector are (x0, y0, z0), the distances between the four LED lighting lamps and the photodetector are R1, R2, R3 and R4, then

[0017]

[0018] Solving the above equation can obtain the coordinates (x0, y0, z0) of the photodetector to realize positioning.

[0019] The solving process is as follows: decomposing the above equation to obtain

[0020]

[0021] Subtracting two from two of the above four equations, the following equation is obtained

[0022]

[0023] Wherein

[0024]

[0025] The above equation is converted into matrix multiplication, as shown in the following equation

[0026]

[0027] According to the above equation, the coordinates (x0, y0, z0) of the photodetector are calculated to realize indoor visible light positioning.

[0028] Preferably, the N-point DFT expansion is as follows

[0029]

[0030] Preferably, the subcarrier allocation is shown as follows

[0031]

[0032] Preferably, the 2N-point IDFT extension is shown as follows

[0033]

[0034] Available

[0035]

[0036] The above equation shows that the former half of the sample can be simply a phase-rotated version of the input QAM sample, and the latter half is redundant due to the antisymmetry property, thus the Nlog2N complex multiplications originally required for the N-point DFT and 2N-point IDFT can be reduced to N complex multiplications. Based on this property, the final real-valued sample S can be generated by concatenating the real and imaginary parts of the former half of y(m) tx As shown in the following equation

[0037]

[0038] Wherein

[0039]

[0040] The application also provides an indoor high-speed visible light communication and positioning integrated device for realizing the indoor high-speed visible light communication and positioning integrated method, comprising,

[0041] A coordinate acquisition unit is configured to acquire coordinates of four LED lighting lamps at four corners of a roof of a rectangular indoor space, and the four LED lighting lamps serve as a signal transmitting end.

[0042] A transmission signal loading unit is configured to load a transmission signal on the signal transmitting end.

[0043] A signal processing unit is configured to perform signal processing on the transmission signal based on a constant envelope orthogonal frequency division multiplexing technology to generate a constant envelope orthogonal frequency division multiplexing signal, and the signal envelope after processing is always a sine function.

[0044] A signal receiving unit is configured to receive the signal after processing by the signal transmitting end.

[0045] A signal processing output unit is configured to perform signal processing on the signal after processing by the signal transmitting end and output the signal, and realize indoor high-speed visible light communication.

[0046] The coordinate calculation unit is used for calculating the coordinates of the photodetector according to the coordinates of the four LED illuminating lamps obtained in step 1, so as to realize indoor visible light positioning

[0047] The present application has the following advantages:

[0048] 1. The large divergence angle of the four LED illuminating lamps in the present application can irradiate all positions of the rectangular indoor ground, and the four LED illuminating lamps serve as signal transmitting ends, and the movable photodetector on the ground of the rectangular indoor space serves as a signal receiving end to receive the signals of the four LED illuminating lamps respectively. The envelope of the constant envelope orthogonal frequency division multiplexing signal generated after the signal processing of the signal transmitting end is always in the form of a sine signal. By using this feature, the LED of the signal transmitting end loads the same envelope of the ordinary signal in addition to the color dimension of the signal, so that the LED can use white light for illumination while loading the transmission signal in one dimension, realizing indoor high-speed visible light communication, and the coordinates of the photodetector can be obtained by acquiring the coordinates of the four LED illuminating lamps, realizing indoor visible light positioning. Therefore, the present application can realize the simultaneous realization of visible light wireless communication and positioning by using the existing LED.

[0049] 2. The signal transmitting end of the present application generates a constant envelope orthogonal frequency division multiplexing signal after signal processing, reduces the peak-to-average power ratio (PAPR), reduces the overall system operating power, and improves the LED signal transmission rate.

[0050] 2. The present application uses constant envelope orthogonal frequency division multiplexing signals, which are easier to make the LED always emit white light for illumination during communication than other signals.

[0051] 3. The present application uses constant envelope orthogonal frequency division multiplexing signals, and the envelope of the modulated signal is always a sine function. Four LEDs can be used to realize accurate positioning of the indoor receiving end, realizing simultaneous communication and positioning. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 The method step flow chart of the present application is an indoor high-speed visible light communication and positioning integrated method.

[0053] Figure 2 The signal processing process flow chart of the signal transmitting end and the signal receiving end in the present application is shown.

[0054] Figure 3 The time domain graph of the constant envelope orthogonal frequency division multiplexing technology in the present application is shown.

[0055] Figure 4 The indoor three-dimensional communication and positioning working structure schematic diagram in the present application is shown. DETAILED DESCRIPTION

[0056] The application will be described in detail below with reference to the accompanying drawings. The following examples are used to illustrate the application, but not to limit the scope of the application.

[0057] Example 1

[0058] As shown in the embodiment of the application, the method specifically comprises the following steps: Figure 1

[0059] Step 1, obtaining the coordinates of four LED lighting lamps at the four corners of the roof of a rectangular indoor space, the four LED lighting lamps serving as signal transmitting ends;

[0060] Step 2, loading a transmission signal on the signal transmitting end;

[0061] Step 3, the signal transmitting end generating a constant envelope orthogonal frequency division multiplexing signal by performing signal processing on the transmission signal based on the constant envelope orthogonal frequency division multiplexing technology, the signal envelope after processing being always a sine function;

[0062] Step 4, a movable photoelectric detector on the ground of the rectangular indoor space serving as a signal receiving end to receive the signal processed by the signal transmitting end;

[0063] Step 5, the signal receiving end performing signal processing on the signal processed by the signal transmitting end in the opposite direction and outputting, to realize indoor high-speed visible light communication;

[0064] Step 6, calculating the coordinates of the photoelectric detector according to the coordinates of the four LED lighting lamps obtained in step 1, to realize indoor high-speed visible light positioning.

[0065] The large divergence angle of the four LED lighting lamps makes them irradiate all positions on the ground of the rectangular indoor space. Meanwhile, the four LED lighting lamps serve as signal transmitting ends, and the movable photoelectric detector on the ground of the rectangular indoor space serves as a signal receiving end to receive the signals of the four LED lighting lamps respectively. The envelope of the constant envelope orthogonal frequency division multiplexing signal generated by the signal transmitting end after signal processing is always a sine signal form. By using this feature, the LED of the signal transmitting end loads ordinary signals with the same envelope in addition to the color dimension of the signal, so that the LED can use white light for illumination while loading a transmission signal in one dimension, to realize indoor high-speed visible light communication. Moreover, the coordinates of the detector can be obtained by acquiring the coordinates of the four LED lighting lamps, to realize indoor visible light positioning.

[0066] Example 2

[0067] The embodiment of the application, the method specifically comprises the following steps:

[0068] ​Step 1, obtaining the coordinates of four LED lighting lamps at the four corners of the roof of a rectangular indoor space, the four LED lighting lamps serving as signal transmitting ends, the four LED lighting lamps adopting RGBA four-dimensional color space, and the four LED lighting lamps respectively using one dimension in the RGBA color space for signal modulation and loading;

[0069] Step 2, loading a transmission signal on the signal transmitting end;

[0070] Step 3, as shown in the figure, the signal transmitting end sequentially performs serial-parallel conversion, QAM mapping, N-point DFT expansion, subcarrier allocation, 2N-point DFT expansion, real / imaginary part connection and parallel-serial conversion processing to generate a constant envelope orthogonal frequency division multiplexing signal, and the signal envelope after processing is always a sine function, wherein, Figure 2

[0071] N-point DFT expansion is shown in the following formula

[0072] Subcarrier allocation is performed on the sample, as shown in the following formula

[0073]

[0074] 2N-point IDFT transformation is performed on the sample, as shown in the following formula

[0075]

[0076] Combining the formulas (1)-(3), we can get

[0077]

[0078] The above equation shows that the first half of the sample can be simply a phase-rotated version of the input QAM sample, and the second half is redundant due to the anti-symmetry property. Therefore, the Nlog2N complex multiplications originally required by N-point DFT and 2N-point IDFT can be reduced to N complex multiplications. Based on this characteristic, the final real-valued sample S tx can be generated by connecting the real part and the imaginary part of the first half of y(m), as shown in the following formula

[0079]

[0080] wherein

[0081]

[0082] ​Since the four LED lights use the RGBA four-dimensional color space, each of the four LED lights modulates and loads signals using one dimension of the RGBA color space. Based on this method, the envelope of the constant envelope orthogonal frequency division multiplexed signal is always a sinusoidal signal. Utilizing this characteristic, in addition to loading the signal in the color dimension, the other color dimensions of the four LED lights are loaded with ordinary signals of the same envelope. This allows the LED lights to provide white light illumination while simultaneously transmitting signals in one dimension, achieving high-speed indoor visible light communication.

[0083] Step 4: A movable photodetector on the floor of the rectangular indoor space serves as a signal receiver to receive the signal processed by the signal transmitter. The photodetector is equipped with filters for four dimensions: RGBA. This photodetector can receive and process signals corresponding to the color dimensions to realize a high-speed visible light communication system indoors.

[0084] Step 5, as follows Figure 2 As shown, the signal receiver sequentially performs parallel-to-serial conversion, real / imaginary part concatenation, antisymmetric mapping, 2N-point DFT transformation, frequency domain equalization, subcarrier inverse allocation, N-point IDFT expansion, QAM inverse mapping, and parallel-to-serial conversion on the signal processed by the signal transmitter before outputting it, thereby realizing high-speed indoor visible light communication.

[0085] Step 6: Since the constant envelope orthogonal frequency division multiplexed signal generated during signal processing at the signal transmitter has a constant envelope in the form of a sinusoidal signal, this signal is highly sensitive to distance information. The transmission distance can be determined by receiving the signal. Therefore, when the receiver receives the signals transmitted by the four LED lights at the transmitter, the transmission distances of the four signals can be obtained; for example... Figure 4 As shown, assuming the coordinates of the four LEDs are (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and (x4, y4, z4), and the coordinates of the receiving end are (x0, y0, z0), and the distances between the four LEDs transmitting signals are R1, R2, R3, and R4, the following equation can be obtained.

[0086] Solving this equation yields the coordinates (x0, y0, z0) of the receiver, enabling localization. The equation can be decomposed as shown below.

[0087]

[0088] Subtracting each of the four equations pairwise, we get the following equation:

[0089]

[0090] in

[0091]

[0092] The above equation is converted into matrix multiplication, as shown in the following formula

[0093]

[0094] Finally, the coordinates (x0, y0, z0) of the position of the photodetector can be obtained, and indoor high-speed visible light positioning can be realized, as shown in Figure 3 The time-domain diagram of the constant envelope OFDM signal is shown, and it can be seen from the diagram that the signal generated by modulation has a constant sinusoidal envelope, and the communication and positioning functions of the system can be simultaneously satisfied.

[0095] Embodiment three

[0096] An indoor high-speed visible light communication and positioning integrated device is used to realize the indoor high-speed visible light communication and positioning integrated method described in any of the above embodiments, comprising,

[0097] A coordinate acquisition unit is configured to acquire the coordinates of four LED lighting lamps at the four corners of the roof of a rectangular indoor space, and the four LED lighting lamps are used as signal transmitting ends.

[0098] A transmission signal loading unit is configured to load a transmission signal on the signal transmitting end.

[0099] A signal processing unit is configured to generate a constant envelope OFDM signal by performing signal processing on the transmission signal based on the constant envelope OFDM technology at the signal transmitting end, and the envelope of the processed signal is always a sinusoidal function.

[0100] A signal receiving unit is configured to receive the processed signal of the signal transmitting end.

[0101] A signal processing output unit is configured to perform signal processing on the processed signal of the signal transmitting end at the signal receiving end, and output the processed signal, thereby realizing indoor high-speed visible light communication.

[0102] A coordinate calculation unit is configured to calculate the coordinates of the photodetector based on the coordinates of the four LED lighting lamps acquired in step 1, thereby realizing indoor visible light positioning.

[0103] Although the specific embodiments of the present application have been described in detail above, the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application, and modifications or changes without creative labor are still within the protection scope of the present application.

Claims

1. A method for integrating indoor high-speed visible light communication and positioning, characterized in that, Specifically, the following steps are included: Step 1: Obtain the coordinates of the four LED lights at the four corners of the roof of the rectangular indoor space. The four LED lights serve as signal transmitters. Step 2: Load the transmission signal onto the signal transmitting end; Step 3: The signal transmitting end processes the transmitted signal using constant envelope orthogonal frequency division multiplexing (OFDM) technology to generate a constant envelope OFDM signal. The envelope of the processed signal is always a sine function. Step 4: A movable photodetector on the floor of the rectangular indoor space serves as a signal receiver to receive the signal processed by the signal transmitter. Step 5: The signal receiver performs the opposite signal processing on the signal processed by the signal transmitter and outputs the signal, thus realizing high-speed indoor visible light communication. Step 6: Calculate the coordinates of the photodetector based on the coordinates of the four LED lights obtained in Step 1 to achieve high-speed visible light positioning indoors. The four LED lights use the RGBA four-dimensional color space, and each of the four LED lights uses one dimension of the RGBA color space for signal modulation and loading. The photodetector has RGBA four-dimensional filters.

2. The method for integrating indoor high-speed visible light communication and positioning according to claim 1, characterized in that, In step 3, the signal transmitting end processes the transmitted signal using constant envelope orthogonal frequency division multiplexing (COFDM) technology to generate a COFDM signal. Specifically, the signal transmitting end performs serial-to-parallel conversion, QAM mapping, N-point DFT expansion, subcarrier allocation, 2N-point DFT expansion, real / imaginary part concatenation, and parallel-to-serial conversion on the transmitted signal to generate a COFDM signal.

3. The method for integrating indoor high-speed visible light communication and positioning according to claim 2, characterized in that, In step 5, the signal receiver performs the opposite signal processing on the signal processed by the signal transmitter and outputs the signal. Specifically, the signal receiver performs parallel-to-serial conversion, real / imaginary part concatenation, antisymmetric mapping, 2N-point DFT transformation, frequency domain equalization, subcarrier inverse allocation, N-point IDFT extension, QAM inverse mapping, and parallel-to-serial conversion on the signal processed by the signal transmitter in sequence and outputs the signal.

4. The method for integrating indoor high-speed visible light communication and positioning according to claim 3, characterized in that, Step 6, calculating the coordinates of the photodetector based on the coordinates of the four LED lights obtained in step 1 to achieve indoor visible light positioning, specifically includes: the coordinates of the four LED lights obtained in step 1 are (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and (x4, y4, z4), respectively. If the coordinates of the photodetector are (x0, y0, z0), and the distances between the four LED lights and the photodetector's signal transmission are R1, R2, R3, and R4 respectively, then... The coordinates (x0, y0, z0) of the photodetector are calculated using the above formula to achieve indoor visible light positioning.

5. The method for integrating indoor high-speed visible light communication and positioning according to claim 2, characterized in that, The N-point DFT expansion is shown in the following equation.

6. The method for integrating indoor high-speed visible light communication and positioning according to claim 5, characterized in that, The subcarrier allocation is shown in the following formula.

7. The method for integrating indoor high-speed visible light communication and positioning according to claim 6, characterized in that, The 2N-point IDFT extension is shown in the following equation. achievable The above equations show that the first half of the sample can be simply regarded as a phase-rotated version of the input QAM sample. Due to the antisymmetric property, the second half is redundant. Therefore, the original Nlog2 N complex multiplications of the N-point DFT and 2N-point IDFT can be reduced to N complex multiplications. Based on this property, the final real-valued sample S can be generated by connecting the real and imaginary parts of the first half of y(m). tx As shown in the following formula in 8. An integrated indoor high-speed visible light communication and positioning device, used to implement the integrated indoor high-speed visible light communication and positioning method according to any one of claims 1-7, characterized in that, include, The coordinate acquisition unit is used to acquire the coordinates of the four LED lights at the four corners of the roof of the rectangular indoor space, and the four LED lights serve as signal transmitters. A signal loading unit is used to load a transmission signal onto the signal transmitting end; The signal processing unit is used at the signal transmitting end to process the transmitted signal based on constant envelope orthogonal frequency division multiplexing technology to generate a constant envelope orthogonal frequency division multiplexed signal. The envelope of the processed signal is always a sine function. The signal receiving unit is used to receive the signal processed by the signal transmitting end. The signal processing output unit is used by the signal receiver to perform the opposite signal processing on the signal transmitter and output the signal, thereby realizing high-speed indoor visible light communication. The coordinate calculation unit is used to calculate the coordinates of the photodetector based on the coordinates of the four LED lights obtained in step 1, so as to achieve indoor visible light positioning.

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