CN106160873A - A kind of phase-shift coding method based on pulse amplitude modulation system and realize device - Google Patents
A kind of phase-shift coding method based on pulse amplitude modulation system and realize device Download PDFInfo
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Abstract
The invention belongs to technical field of visible light communication, a kind of phase-shift coding method directly detecting pulse amplitude modulation system based on directly modulation and realize device.In the present invention, in system transmitting terminal, the phase-shift coding method to the parity symbols employing contrary sign of consecutive symbol sequences；At system receiving terminal, the adjacent-symbol of receiving symbol is postponed the differential decoding method subtracted each other.It realizes device accordingly, comprises phase-shift coder, PAM mapping block, string also/parallel serial conversion module at transmitting terminal, up-samples module, LED and driving module thereof；Differential decoder, serioparallel exchange module, post-equalization module, PAM De-mapping module, clock synchronization module, normalization module, down-sampled module, condenser lens, optical filter and receiver is comprised at receiving terminal.Use apparatus of the present invention and decoding method, can effectively eliminate the crosstalk noise between intrinsic DC component and signal present in visible light communication system based on pulse amplitude modulation form, increase receiver sensitivity, improve signal transmission quality, be effectively improved systematic function.And the method to realize process simple, it is easy to integrated.
Description
Technical Field
The invention belongs to the technical field of visible light communication, and particularly relates to a Phase Shift (PS) coding method and an implementation device based on a Pulse Amplitude Modulation (PAM) system.
Background
Currently, white Light Emitting Diodes (LEDs) are widely used in various fields, such as illumination, signal emission, display, and the like. Compared with other common light sources such as incandescent lamps and fluorescent lamps, the white light LED has higher modulation bandwidth. In addition, the white light LED also has the advantages of good modulation performance, high response sensitivity and the like. By utilizing the characteristics of the LED, signals can be modulated on light emitted by the LED for transmission, so that the effective integration of illumination and communication is realized. Visible Light Communication (VLC) is a new green information technology that uses the fast response characteristic of LEDs to achieve high-speed data transmission.
Compared with other wireless communication technologies, the VLC technology has the advantages of high transmission rate, good safety, strong confidentiality, no electromagnetic radiation, environmental friendliness and the like, and has become a hotspot of research in the communication field in recent years. There are some limiting factors in its development, and one of the important challenges is that the limited bandwidth of LEDs limits the transmission rate and system performance of VLC systems. In order to realize high-speed transmission of VLC systems, researchers typically employ advanced high-order modulation techniques to code-modulate raw data. Pulse amplitude modulation is widely researched and applied as a simple and feasible modulation mode. Moreover, PAM4 became a new standard for IEEE p802.3bs 400Gbs at the IEEE 802.1/IEEE 802.3 conference in 2015, thus showing that PAM modulation is a potentially useful transmission scheme.
However, for PAM visible light communication systems directly detected by direct modulation, crosstalk noise between signals existing in the systems will seriously deteriorate system performance, and natural frequency noise caused by direct detection also has a certain influence on system performance. Aiming at the problem, the coding and decoding method provided by the invention can inhibit the direct current component and quadratic term noise of the signal, reduce the deterioration of the noise to the system performance and improve the system performance by controlling the spectrum shape of the coded signal at the transmitting end and carrying out subtraction operation on adjacent code elements at the receiving end.
Disclosure of Invention
The invention aims to provide a phase shift coding method and a realization device of a Pulse Amplitude Modulation (PAM) system based on direct modulation and direct detection, which are used for realizing visible light high-speed communication based on PAM modulation and solving the problem that the existing PAM modulation technology is seriously influenced by signal crosstalk noise, thereby improving the transmission performance of the system.
The phase shift coding method based on the direct modulation direct detection PAM system provided by the invention adopts a phase shift coding mode of opposite signs for the parity signs of the original signals and adopts a differential decoding mode of delayed subtraction for the received signals, which is specifically expressed as follows: the PAM signal transmitted by the baseband controls the low-frequency component of the frequency spectrum, and the received signal suppresses the crosstalk noise between the direct-current component and the signal.
Specifically, at the transmitting end, the PAM modulated signal is phase shift encoded, the modulated PAM symbols are divided into different symbol blocks, each group of symbol blocks contains two consecutive symbols, and the second symbol is the inverse of the first symbol. Wherein the baseband PAM signal in the kth code element block of the transmitting terminalAndcan be respectively expressed as:
wherein,symbols representing PAM mappings.
And at a receiving end, carrying out differential decoding on the signals to obtain the photocurrent. Photocurrent in kth group of symbol blocks of receiving endCan be expressed as:
wherein the coefficientsRepresenting the strength ratio of the PAM baseband signal;andrespectively representing the bias voltage and the reverse voltage of the LED;andrepresenting the noise current in the 2k-1 and 2k symbols, respectively, in the k-th group of symbol blocks.
The invention also discloses a device for realizing phase shift coding and differential decoding based on the direct modulation PAM system, which comprises a corresponding transmitting end and a corresponding receiving end; the transmitting terminal comprises a phase shift encoder, a PAM mapping module, a serial-parallel/parallel-serial conversion module, an up-sampling module, an LED and a driving module thereof; the receiving end comprises a differential decoder, a serial-parallel conversion module, a post-equalization module, a PAM demapping module, a clock synchronization module, a normalization module, a down-sampling module, a focusing lens, an optical filter and a receiver; wherein:
the phase-shift encoder is used for performing phase-shift encoding on the signal;
the PAM mapping module is used for coding and modulating signals;
the serial-to-parallel/parallel-to-serial conversion module is used for sequence conversion before and after signal coding;
the up-sampling module is used for up-sampling signals;
the LED and the driving module thereof are used for loading signals on the LED and transmitting the signals through free space;
the differential decoder is used for differentially decoding the signals;
the serial-parallel conversion module is used for converting the sequence after the signal decoding;
the post-equalization module is used for equalizing the decoded signal;
the PAM demapping module is configured to demodulate the PAM signal into a binary bit stream;
the clock synchronization module is used for performing clock extraction and synchronization on the received signals;
the normalization module is used for performing average power normalization processing on the received signals;
the down-sampling module is used for down-sampling the signal;
the focusing lens, the optical filter and the receiver are used for receiving optical signals and converting the optical signals into electric signals.
The invention utilizes the Wavelength Division Multiplexing (WDM) technology to transmit the PAM signals with different wavelengths based on phase shift coding on the red, green and blue wave bands, and carries out corresponding differential decoding on a receiving end, thereby realizing the high-speed transmission of the phase shift coding PAM signals in a visible light communication system.
The working process of the device of the invention is as follows:
at the transmitting end:
(1) PAM mapping is carried out on the original binary bit stream by a PAM mapping module to generate a multi-level PAM signal;
(2) the up-sampling module performs 2 times up-sampling on the mapped PAM symbol to prepare for serial-to-parallel conversion of signals;
(3) the serial-parallel conversion module carries out serial-parallel conversion on the signals, divides the serial signals into two paths of parallel signals and prepares for phase shift coding;
(4) the phase-shift encoder inverts the input second path of signals and delays the signals by T/2 bits;
(5) the parallel-serial conversion module combines the two parallel signals into one signal, so that each code element signal is followed by the inverse signal of the code element signal;
(6) the up-sampling module up-samples the coded signal and is used for inputting an Arbitrary Waveform Generator (AWG);
(7) the LED and the driving module thereof couple the signal emitted by the AWG to a red, green and blue (RGB) LED through a pre-equalization plate, an electrical amplifier and an AC-DC coupler, and the signal and the bias voltage are emitted out through a free space.
At the receiving end:
(1) the receiver distinguishes transmission signals of three different wave bands of red, green and blue through a focusing lens and a filter, then the received optical signals are converted into electric signals through the receiver, and a real-time oscilloscope with high-speed sampling is used for collecting the signals to complete the next off-line processing;
(2) the clock synchronization module performs clock synchronization on the signals acquired by the oscilloscope to find a signal head;
(3) the normalization module normalizes the average power used by the received signal;
(4) the down-sampling module performs 4 times down-sampling on the received signal;
(5) the serial-parallel conversion module converts the serial signals into two parallel signals to prepare for differential decoding;
(6) the differential decoder delays the parallel second path of signals by T/2 bits, and subtracts the delayed second path of signals from the first path of signals to obtain decoding signals;
(7) the post-equalization module performs post-equalization on the decoded signal to compensate the intersymbol interference of the signal;
(8) the PAM demapping module demaps the PAM signal into a binary bit stream.
The invention has the beneficial effects that: the phase shift coding and the differential decoding are adopted to carry out visible light transmission of the PAM modulation signal, so that direct current components in the received signal and crosstalk noise between the signals can be effectively inhibited, and the sensitivity of the receiver is improved. The invention is suitable for the field of visible light communication, is used for solving the problem that crosstalk noise seriously deteriorates the system performance in a visible light communication system based on PAM modulation, and greatly improves the transmission performance of the system.
Drawings
Fig. 1 is a schematic diagram of a phase shift encoded PAM signal as proposed by the present invention.
Fig. 2 is a schematic diagram of a PAM system implementation apparatus based on phase shift coding according to the present invention.
Fig. 3 is a schematic diagram of the application of the present invention in a WDM-based visible light communication system.
Fig. 4 is a graph comparing the frequency spectrum of a phase shift encoded PAM signal and an uncoded PAM signal according to the present invention.
Fig. 5 uncoded PAM-8 received signal spectrum.
Fig. 6 phase shift encoded PAM-8 received signal spectrum proposed by the present invention.
Fig. 7 signal spectrum directly decoded by phase shift encoded PAM-8 proposed by the present invention.
Fig. 8 shows the spectrum of a phase shift encoded PAM-8 differentially decoded signal according to the invention.
Fig. 9 PAM-8 signal constellations without encoding, phase shift encoding and direct decoding, and phase shift encoding and differential decoding.
Fig. 10 study of bit error rate performance as a function of bit rate for phase shift encoded PAM-8 signals in red transmission with differential decoding and direct decoding.
Fig. 11 study of bit error rate performance as a function of bit rate for phase shift encoded PAM-8 signals in green transmission with differential decoding and direct decoding.
Fig. 12 is a study of bit error rate performance as a function of bit rate for phase shift encoded PAM-8 signals in blue transmission with differential decoding and direct decoding.
Fig. 13 is a study of the bit error rate performance of phase shift encoded and differentially decoded PAM-8 signals in red light transmission as a function of specific distance.
Fig. 14 is a study of phase shift encoded and differentially decoded PAM-8 signal error rate performance as a function of specific distance in green transmission.
Fig. 15 is a study of phase shift encoded and differentially decoded PAM-8 signal bit error rate performance as a function of specific distance in blue light transmission.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
The invention aims to provide a Phase Shift (PS) coding method of a pulse amplitude modulation system (PAM) based on direct modulation and direct detection and an implementation device thereof in a visible light communication system. The method can reduce the influence of the inherent noise of the system and the crosstalk noise between signals on the system, improve the system performance and obtain higher transmission rate. We will describe in detail specific embodiments in terms of both principle analysis and experimental transmission.
First, principle analysis
The coding scheme proposed by the present invention is shown in fig. 1. In a phase-shift encoder at the transmitting end, successive symbols are divided into different blocks, each block of symbols comprising two symbols, the second symbol having exactly the opposite sign of the first symbol. In the group of symbols, the first symbol of the first group isThe second symbol in the first group isBy analogy, one symbol in the kth group isSecond code element。
The encoded baseband PAM signal can be represented as:
(1)
(2)
wherein,symbols representing PAM mappings.
The coded PAM signal is modulated to the LED lamp through the AC-DC coupler, and the signal emitted by the LED can be expressed as follows:
(3)
wherein,andrespectively representing the bias current and the reverse current of the LED; coefficient of performanceRepresents the intensity of the PAM signal;to representThe center frequency of the LED light emission;represents a unit coefficient;representing time.
After the signal emitted by the LED is transmitted in free space, the received signal can be expressed as:
(4)
wherein,representing additive white gaussian noise.
The receiver may convert the optical signal into an electrical signal. Since the receiver uses square-law detection, the signal current in the kth symbol set can be approximated as:
(5)
(6)
(7)
wherein,the first term in equation (5) represents the dc component of the received signal, the second term represents the signal component, the third term represents the crosstalk noise between the signals, and the fourth term is the other noise as listed in equation (6). The beat noise of AWGN versus AWGN is represented in equation (6), and the second term represents the beat noise of the signal versus AWGN.
The second term photocurrent in the k-th symbol block can be expressed by equation (7). By the subtraction operation of equation (5) and equation (7), the photocurrent in the kth symbol block can be obtained as follows:
(8)
wherein the first term represents the signal and the second term represents the noise. Comparing equation (8) and equation (5), it can be found that both the dc component of the signal and the quadratic crosstalk noise can be completely eliminated and the strength of the received signal is doubled, i.e. the receiver sensitivity can be improved by 3 dB. Therefore, the signal-to-noise ratio of the system can be effectively improved by adopting the phase shift coding and differential decoding methods, so that the system performance is improved.
Second, Transmission experiment
In order to test the feasibility of the method in a visible light communication system, a transmission verification experiment is carried out by adopting an implementation device of a direct modulation PAM system based on phase shift coding. The device schematic diagram and the system architecture diagram of the system are respectively shown in fig. 2 and fig. 3. The device comprises a transmitting end and a receiving end.
The transmitting terminal comprises a phase shift encoder, a PAM mapping module, a serial-parallel/parallel-serial conversion module, an LED and a driving module thereof and the like. Comprises the following steps:
step 101: the PAM mapping module is used for carrying out PAM mapping on the original binary bit stream to generate a multi-level PAM signal;
step 102: the up-sampling module is used for carrying out 2 times up-sampling on the mapped PAM symbol and preparing for serial-parallel conversion of signals;
step 103: the serial-parallel conversion module is used for carrying out serial-parallel conversion on the signals, dividing the serial signals into two paths of parallel signals and preparing for phase shift coding;
step 104: the phase-shift coder is used for inverting the input second path of signals and delaying the T/2 bit;
step 105: the parallel-serial conversion module is used for combining the two parallel signals into one signal, so that each code element signal is followed by the inverse signal of the code element signal;
step 106: and the up-sampling module is used for up-sampling the coded signals and inputting the signals into an Arbitrary Waveform Generator (AWG).
Step 107: the LED and the driving module thereof couple the emission signal and the bias voltage to the red, green and blue (RGB) LED through the pre-equalization plate, the electric amplifier and the AC-DC coupler and emit the signals through the free space.
The receiving end comprises a differential decoder, a PAM demapping module, a serial-parallel conversion module, a receiver module and the like. Comprises the following steps:
step 201: the receiver module is used for distinguishing transmission signals of three different wave bands of red, green and blue through a focusing lens and a filter, then converting received optical signals into electric signals through the receiver, and collecting the signals by using a high-speed sampling real-time oscilloscope so as to complete the next off-line processing;
step 202: the clock synchronization module is used for carrying out clock synchronization on the signals acquired by the oscilloscope to find out a signal head;
step 203: a normalization module for normalizing the average power used by the received signal;
step 204: the down-sampling module performs 4-time down-sampling on the received signal;
step 205: the serial-parallel conversion module is used for converting the serial signals into two parallel signals and preparing for differential decoding;
step 206: the differential decoder delays the parallel second path of signals by T/2 bits and subtracts the delayed second path of signals from the first path of signals to obtain decoding signals;
step 207: a post-equalization module for post-equalizing the decoded signal to compensate for inter-symbol interference of the signal;
step 208: and the PAM demapping module is used for demapping the PAM signal into a binary bit stream.
The steps in this embodiment are divided for clarity of description, and implementation may be combined into one step or split into multiple steps, so long as the steps include the same logical relationship, which is within the scope of the present invention.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.
We tested the experimental device for signal transmission in free space at a distance of 1-2 m. Fig. 4 is a graph comparing the frequency spectrum of a phase shift encoded PAM signal and an uncoded PAM signal according to the present invention. It can be seen that the low frequency components in the encoded spectrogram are suppressed, and the high frequency components are preserved as much as possible, which is advantageous for resisting low frequency attenuation in visible light channel transmission.
Fig. 5 shows the spectrum of an uncoded PAM-8 received signal after 1m free space transmission. It can be seen that the spectrum has a large dc component and that there is strong signal fading and distortion at the low frequencies of the spectrum. This is because the visible channel has a large signal attenuation at low frequencies. And the AC-DC coupler in the experimental device can not pass through the DC component of the signal, and the DC component in the received frequency spectrum is the fixed frequency noise component introduced by the square law detection of the receiver. Therefore, for uncoded received signals, the performance is severely impaired and cannot be transmitted directly in the visible light channel.
Fig. 6 shows the spectrum of an uncoded PAM-8 received signal after 1m free space transmission. The spectrum is flat over a 400MHz bandwidth.
Fig. 7 shows the signal spectrum after phase shift encoded PAM-8 direct decoding according to the present invention. The spectrum has a direct current component introduced by receiver square law detection and is rich in low-frequency noise.
Fig. 8 shows the frequency spectrum of a phase shift encoded PAM-8 differentially decoded signal according to the present invention. The spectrum has no dc component and the noise intensity is greatly suppressed.
Fig. 9 is a PAM-8 signal constellation without encoding, phase shift encoding and direct decoding, and phase shift encoding and differential decoding. The uncoded signal can be seen to have the worst performance, and the original signal can not be solved at all; phase shifting the S encoded and directly decoded signal one time; the signal performance of the phase shift coding and the differential decoding is optimal, and the original signal can be recovered.
The invention also tests the bit error rate performance of the signals transmitted by the red, green and blue lights under the conditions of direct decoding and differential decoding at different rates, which are respectively shown in fig. 10, fig. 11 and fig. 12. It can be seen that the total rate of the differentially decoded signal can reach 3.375Gb/s (red light: 1.35 Gb/s; green light: 0.975 Gb/s; blue light: 1.05 Gb/s) under the 7% FEC threshold; the total rate of the directly decoded signal can reach 1.8Gb/s (the rate of light of all three colors is 600 Mb/s). Therefore, the rate is improved by 1.575Gb/s through differential decoding.
In addition, the performance of error rate variation of signals transmitted by red, green and blue lights at different distances was tested, as shown in fig. 13, 14 and 15. The transmission rates are 3.375Gb/s, 3.225-Gb/s and 2.925-Gb/s at transmission distances of 1m, 1.5m and 2m, respectively.
The transmission experiment verifies the feasibility of the phase shift coding scheme and the implementation device in a visible light communication system based on PAM modulation and the inhibition effect on system noise, and the system performance can be greatly improved.
Claims (4)
1. A phase shift coding method of pulse amplitude modulation system based on direct modulation and direct detection is characterized in that a phase shift coding mode of opposite sign is adopted for parity sign of original signal, and a differential decoding mode of delay subtraction is adopted for received signal; the concrete expression is as follows: the PAM signal transmitted by the baseband controls the low-frequency component of the frequency spectrum, and the received signal suppresses the crosstalk noise between the direct-current component and the signal.
2. The phase shift encoding method as set forth in claim 1, wherein:
at the transmitting end, dividing the continuous transmitted signal into different symbol blocks, each symbol block containing two adjacent symbols, and the second symbol being the inverse of the first symbol; wherein, the baseband PAM signal in the kth code element block of the transmitting terminalAndrespectively expressed as:
wherein,a symbol representing a PAM mapping;
at the receiving end, the photocurrent in the kth group of symbol blocksExpressed as:
wherein the coefficientsRepresenting the strength ratio of the PAM baseband signal;andrespectively representing the bias voltage and the reverse voltage of the LED;andrepresenting the noise current in the 2k-1 and 2k symbols, respectively, in the k-th group of symbol blocks.
3. An implementation device of a phase shift coding method of a pulse amplitude modulation system based on direct modulation and direct detection comprises a corresponding transmitting end and a corresponding receiving end; the method is characterized in that: the transmitting terminal comprises a phase shift encoder, a PAM mapping module, a serial-parallel/parallel-serial conversion module, an up-sampling module, an LED and a driving module thereof; the receiving end comprises a differential decoder, a serial-parallel conversion module, a post-equalization module, a PAM demapping module, a clock synchronization module, a normalization module, a down-sampling module, a focusing lens, an optical filter and a receiver; wherein:
the phase-shift encoder is used for performing phase-shift encoding on the signal;
the PAM mapping module is used for coding and modulating signals;
the serial-to-parallel/parallel-to-serial conversion module is used for sequence conversion before and after signal coding;
the up-sampling module is used for up-sampling signals;
the LED and the driving module thereof are used for loading signals on the LED and transmitting the signals through free space;
the differential decoder is used for differentially decoding the signals;
the serial-parallel conversion module is used for converting the sequence after the signal decoding;
the post-equalization module is used for equalizing the decoded signal;
the PAM demapping module is configured to demodulate the PAM signal into a binary bit stream;
the clock synchronization module is used for performing clock extraction and synchronization on the received signals;
the normalization module is used for performing average power normalization processing on the received signals;
the down-sampling module is used for down-sampling the signal;
the focusing lens, the optical filter and the receiver are used for receiving optical signals and converting the optical signals into electric signals.
4. The implementation apparatus of claim 3, wherein: the working flow of the device is as follows:
at the transmitting end:
(1) PAM mapping is carried out on the original binary bit stream by a PAM mapping module to generate a multi-level PAM signal;
(2) the up-sampling module performs 2 times up-sampling on the mapped PAM symbol to prepare for serial-to-parallel conversion of signals;
(3) the serial-parallel conversion module carries out serial-parallel conversion on the signals, divides the serial signals into two paths of parallel signals and prepares for phase shift coding;
(4) the phase-shift encoder inverts the input second path of signals and delays the signals by T/2 bits;
(5) the parallel-serial conversion module combines the two parallel signals into one signal, so that each code element signal is followed by the inverse signal of the code element signal;
(6) the up-sampling module up-samples the coded signal and is used for inputting an Arbitrary Waveform Generator (AWG);
(7) the LED and the driving module thereof couple the signal emitted by the AWG to a red, green and blue (RGB) LED through a pre-equalization plate, an electric amplifier and an AC-DC coupler and emit the signal and bias voltage through free space;
at the receiving end:
(1) the receiver distinguishes transmission signals of three different wave bands of red, green and blue through a focusing lens and a filter, then the received optical signals are converted into electric signals through the receiver, and a real-time oscilloscope with high-speed sampling is used for collecting the signals to complete the next off-line processing;
(2) the clock synchronization module performs clock synchronization on the signals acquired by the oscilloscope to find a signal head;
(3) the normalization module normalizes the average power used by the received signal;
(4) the down-sampling module performs 4 times down-sampling on the received signal;
(5) the serial-parallel conversion module converts the serial signals into two parallel signals to prepare for differential decoding;
(6) the differential decoder delays the parallel second path of signals by T/2 bits, and subtracts the delayed second path of signals from the first path of signals to obtain decoding signals;
(7) the post-equalization module performs post-equalization on the decoded signal to compensate the intersymbol interference of the signal;
(8) the PAM demapping module demaps the PAM signal into a binary bit stream.
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| CN109286431A (en) * | 2018-09-21 | 2019-01-29 | 复旦大学 | A kind of equiprobability method for precoding for receiving system based on the hair of pulse amplitude modulation two one |
| CN110266396A (en) * | 2019-06-21 | 2019-09-20 | 上海交通大学 | A kind of optics PAM-4 signal receiver and full light quantization method |
| CN110727681A (en) * | 2019-09-27 | 2020-01-24 | 北京智道合创科技有限公司 | Data storage method and device |
| CN111107033A (en) * | 2019-12-20 | 2020-05-05 | 重庆邮电大学 | Downlink frame timing synchronization method for 5G system |
| CN111865848A (en) * | 2020-06-16 | 2020-10-30 | 武汉邮电科学研究院有限公司 | Signal modulation format identification method and system |
| CN113037380A (en) * | 2021-03-23 | 2021-06-25 | 深圳市南科信息科技有限公司 | Visible light imaging communication method and system based on multi-channel PAM |
| CN113193920A (en) * | 2021-04-27 | 2021-07-30 | 苏州大学 | Probability shaping PAM-4 signal transmission method and device |
| CN113315575A (en) * | 2021-06-01 | 2021-08-27 | 天津大学 | Visual optical communication method of self-adaptive threshold decoding |
| CN113507325A (en) * | 2021-06-30 | 2021-10-15 | 同济大学 | IMDD optical communication system based on nonlinear differential coding and quadratic VNLE |
| CN115333557A (en) * | 2022-07-21 | 2022-11-11 | 深圳市纽瑞芯科技有限公司 | Wake-up transceiver system of UWB device |
| WO2023207750A1 (en) * | 2022-04-24 | 2023-11-02 | 华为技术有限公司 | Signal processing method and apparatus |
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| CN109286431A (en) * | 2018-09-21 | 2019-01-29 | 复旦大学 | A kind of equiprobability method for precoding for receiving system based on the hair of pulse amplitude modulation two one |
| CN110266396A (en) * | 2019-06-21 | 2019-09-20 | 上海交通大学 | A kind of optics PAM-4 signal receiver and full light quantization method |
| CN110727681A (en) * | 2019-09-27 | 2020-01-24 | 北京智道合创科技有限公司 | Data storage method and device |
| CN110727681B (en) * | 2019-09-27 | 2022-07-08 | 北京智道合创科技有限公司 | Data storage method and device |
| CN111107033A (en) * | 2019-12-20 | 2020-05-05 | 重庆邮电大学 | Downlink frame timing synchronization method for 5G system |
| CN111107033B (en) * | 2019-12-20 | 2022-04-01 | 重庆邮电大学 | Downlink frame timing synchronization method for 5G system |
| CN111865848B (en) * | 2020-06-16 | 2023-03-24 | 武汉邮电科学研究院有限公司 | Signal modulation format identification method and system |
| CN111865848A (en) * | 2020-06-16 | 2020-10-30 | 武汉邮电科学研究院有限公司 | Signal modulation format identification method and system |
| CN113037380A (en) * | 2021-03-23 | 2021-06-25 | 深圳市南科信息科技有限公司 | Visible light imaging communication method and system based on multi-channel PAM |
| CN113193920A (en) * | 2021-04-27 | 2021-07-30 | 苏州大学 | Probability shaping PAM-4 signal transmission method and device |
| CN113315575A (en) * | 2021-06-01 | 2021-08-27 | 天津大学 | Visual optical communication method of self-adaptive threshold decoding |
| CN113315575B (en) * | 2021-06-01 | 2022-10-28 | 天津大学 | Visual optical communication method of self-adaptive threshold decoding |
| CN113507325A (en) * | 2021-06-30 | 2021-10-15 | 同济大学 | IMDD optical communication system based on nonlinear differential coding and quadratic VNLE |
| WO2023207750A1 (en) * | 2022-04-24 | 2023-11-02 | 华为技术有限公司 | Signal processing method and apparatus |
| WO2024016870A1 (en) * | 2022-07-18 | 2024-01-25 | 苏州旭创科技有限公司 | Signal processing method, device, and system |
| CN115333557A (en) * | 2022-07-21 | 2022-11-11 | 深圳市纽瑞芯科技有限公司 | Wake-up transceiver system of UWB device |
| CN115333557B (en) * | 2022-07-21 | 2024-01-16 | 深圳市纽瑞芯科技有限公司 | Wake-up transceiver system of UWB equipment |
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