Wireless energy information cooperative transmission method and system based on polarization modulation

Abstract

The invention discloses a wireless energy information cooperative transmission method and system based on polarization modulation, the system is composed of a transmitting end and a receiving end, the transmitting end comprises a radio frequency power source, a radio frequency switch and a transmitting antenna; the receiving end comprises a receiving antenna, two rectifying circuits, a voltage comparator, an information decoding module and an energy management module. The radio frequency switch is integrated with the transmitting antenna, and the receiving antenna is integrated with the rectifying circuit, so that the size is effectively reduced; a frequency mixer and a local oscillator required in a traditional demodulation circuit can be omitted at the receiving end, and energy consumed by information demodulation is reduced. Meanwhile, a battery is not needed, energy is only provided by a radio frequency signal output in the transmitting end, and the energy is collected and boosted through the energy management module to supply power to equipment; according to the method, energy and information transmission do not need to be balanced, high-speed information transmission can be realized on the premise of keeping high energy conversion efficiency, and the robustness is high.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless signal and energy simultaneous transmission, and in particular to a method and system for wireless energy information collaborative transmission based on polarization modulation. Background Art

[0002] Simultaneous Wireless Information and Power Transfer (SWIPT) combines wireless information transfer (WIT) with wireless power transfer (WPT), which can provide energy to wireless devices and exchange information with wireless devices. SWIPT integrates radio frequency energy transmission technology into traditional wireless communication networks. It can charge sensor nodes while transmitting sensor node measurement information using microwaves, which is very suitable for applications that require large-scale deployment of terminal nodes. This technology provides continuous low-power energy to terminal electronic devices in a battery-free manner. It has outstanding advantages in power consumption, spectrum utilization and transmission delay, greatly improving the integration level, and has important application value in the development of the Internet of Things, smart homes and medical facilities.

[0003] There are four main methods for the system topology of traditional simultaneous signal and energy transmission, namely time switching, power division, frequency division and space division. However, these methods separate information transmission from energy transmission. Over-emphasizing information transmission will reduce energy conversion efficiency, so the trade-off between information transmission and energy transmission must be considered. At the same time, in the traditional receiver architecture of simultaneous signal and energy transmission, information and energy are processed by independent information processing modules and energy processing modules respectively, resulting in low system integration and poor flexibility. Although most of the receiver architectures developed in recent years adopt an integrated form, it will still affect energy transmission to a certain extent, and the architecture has low anti-interference ability, resulting in unstable system energy conversion efficiency.

[0004] With the iterative development of wireless power supply and mobile communication technology, the concept of green communication has made the industry focus on low-loss energy collection. However, the existing information-energy transmission technology still has the defect of reasonably balancing communication rate and energy transmission efficiency. Therefore, how to ensure stable and efficient energy output while correctly and effectively transmitting information, and improve system integration and flexibility, is a problem that needs to be solved in the field of wireless energy information collaborative transmission technology. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, an object of the present invention is to provide a method and system for cooperative transmission of wireless energy information based on polarization modulation.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A wireless energy information cooperative transmission system based on polarization modulation, comprising a transmitting end and a receiving end;

[0008] The transmitting end comprises:

[0009] A radio frequency power source, used to output the radio frequency signal required by the system;

[0010] A radio frequency switch, used for switching the radio frequency signal to a horizontal or vertical polarization port;

[0011] A transmitting antenna, used for transmitting a radio frequency signal switched to a horizontal or vertical polarization port;

[0012] The receiving end comprises:

[0013] A receiving antenna, used for receiving a radio frequency signal of a fixed polarization mode radiated by a transmitting antenna;

[0014] Two rectifier circuits are respectively connected to two polarization ports of the receiving antenna to convert the radio frequency signal into a direct current signal;

[0015] A voltage comparator is used to compare the voltages of the two rectifier circuits;

[0016] An information decoding module is connected to the output end of the voltage comparator and is used to demodulate the serial port information corresponding to the radio frequency signal;

[0017] The energy management module is used to store the DC energy output by the two rectifier circuits.

[0018] Furthermore, the radio frequency switch is integrated with the transmitting antenna.

[0019] Furthermore, the radio frequency switch is of a single-pole double-throw type and is controlled by a serial port signal generated by a computer using a UART protocol.

[0020] Furthermore, the two rectifier circuits are integrated on the receiving antenna.

[0021] Furthermore, the transmitting antenna, receiving antenna and two rectifier circuits operate in the same frequency band.

[0022] Furthermore, the transmitting antenna and the receiving antenna are both high-gain dual-port dual-linear polarization antennas.

[0023] Furthermore, the energy management module includes a voltage conversion unit, an energy storage unit and a power management unit.

[0024] Furthermore, the two rectifier circuits have the same structure, and their topological structures are both parallel single-tube rectifier circuits.

[0025] Furthermore, the information decoding module is specifically an MCU with an OLED screen.

[0026] A simultaneous transmission method based on the wireless energy information cooperative transmission system comprises:

[0027] Transmitter:

[0028] The radio frequency power source transmits a radio frequency signal;

[0029] The computer uses the UART protocol to generate a serial port signal, which is input into the double-throw port of the RF switch to control the switching of the transmitting antenna polarization;

[0030] The radio frequency signal is transmitted into free space via the transmitting antenna;

[0031] Receiver:

[0032] The receiving antenna receives the radio frequency signal and inputs it into a corresponding rectifier circuit;

[0033] The rectifier circuit converts the RF signal into a DC signal and outputs the DC signal to the energy management module for powering external devices and completing the energy transmission function;

[0034] The DC signal generated by the rectifier circuit is simultaneously input into the corresponding in-phase / inverting ports of the voltage comparator to obtain high and low levels representing different code elements, and the encoded information is input into the information decoding module to complete the information transmission.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] First, the present invention has the advantages of simple structure, high integration and small size. The information transmission link and the energy transmission link of the present invention share an antenna. There is no need to design an antenna for each link separately. Only a single-frequency dual-polarization transmitting antenna and a receiving antenna need to be designed. Information does not need to be added to the carrier, so the transmitting end does not need a mixer, and the receiving end does not need a mixer and a local oscillator, which reduces the cost and system complexity. At the same time, the RF switch is integrated on the back of the transmitting antenna, and the rectifier circuit is integrated on the back of the receiving antenna, with a compact structure and high integration. In summary, the volume of the transmitter and the receiver can be effectively reduced, which is conducive to miniaturization.

[0037] Second, based on the low power consumption characteristics of the present invention and the proposed energy management module, the receiving device can work without a battery, and the energy is completely provided by the transmitting end. The present invention reduces modules such as mixers, local oscillators, and phase shifters, and the power consumed by these modules accounts for most of the information demodulation process. Reducing these devices can greatly reduce power consumption. The energy management module stores energy and boosts low-voltage direct current to the rated voltage of the equipment. Through a reasonable energy management solution, it can optimize energy utilization efficiency and increase equipment working time. The feature that the receiving device does not require additional power supply reduces operations such as battery and wired power supply, which is beneficial to the maintenance of the receiving device.

[0038] Third, the transmission of information by the present invention will not reduce the energy conversion efficiency. Traditional wireless signal-energy simultaneous transmission schemes, such as power division, first allocate power to the signal link and the energy link in a certain ratio. Therefore, to increase the information transmission rate, more power needs to be allocated to the information link. If the power allocated to the rectifier is reduced, the conversion efficiency will decrease. In the present invention, the RF signal is first converted into DC energy by a rectifier, and then the information is demodulated by performing an envelope detection-like operation on the rectified voltage. Unlike traditional schemes, this is a process of rectifying first and then demodulating the information. Increasing the information transmission rate will not reduce the input power of the rectifier, so transmitting information will not reduce the transmission energy efficiency.

[0039] Fourth, the wireless signal-energy simultaneous transmission scheme proposed in the present invention has higher energy conversion efficiency than traditional schemes. In traditional modulation technologies such as amplitude modulation and frequency modulation technology, the modulated signal is not a constant envelope waveform, and the transmission of different code elements will cause a huge change in the waveform. For the rectifier circuit, this not only reduces the conversion efficiency, but also increases the output ripple, which is not conducive to energy transmission. Ordinary continuous waves are constant envelope signals. Therefore, compared with continuous waves, the transmission of modulation information will inevitably reduce the conversion efficiency of the rectifier. The modulation scheme proposed in the present invention still uses a radio frequency continuous wave as the modulated signal, and the transmission of different code elements only changes the polarization of the radio frequency wave, which will not reduce the rectifier conversion efficiency. Therefore, it has higher energy conversion efficiency than traditional schemes.

[0040] Fifth, the information transmission of the present invention has an extremely low bit error rate and good robustness. In this system, the transmitted code element is judged by judging the output voltage of the rectifier circuit. If the judgment of the rectifier voltage is wrong, a bit error will occur. When the transmission power is low or the transmission distance is far, the rectifier voltage is low, and a high level may be misjudged as a low level. When the transmission power is very high or the transmission distance is very close, due to the multipath effect and insufficient antenna isolation, the rectifier that should not work will also have an output voltage, and a low level may be misjudged as a high level. The vertical polarization wave and the horizontal polarization wave themselves have a large isolation, so the output voltage of the corresponding polarization rectifier circuit is always higher than the output voltage of the non-corresponding polarization circuit. Therefore, the use of a voltage comparator can correctly judge the high and low levels, reduce the bit error rate, and at the same time reduce the antenna's requirements for isolation and cross-polarization ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural block diagram of the wireless energy information cooperative transmission system based on polarization modulation of the present invention;

[0042] Figure 2 is a signal transmission flow chart of a transmitting end in an embodiment of the present invention;

[0043] Figure 3 is a flow chart of signal transmission at a receiving end in an embodiment of the present invention;

[0044] Figure 4 It is a comparison chart of the energy conversion efficiency of the transmission system of the embodiment of the present invention and a separate wireless energy transmission link without information. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto.

[0046] Example

[0047] like Figure 1As shown, a wireless energy information cooperative transmission system based on polarization modulation includes two parts: a transmitter and a receiver. The transmitter includes: an RF power source, an RF switch and a transmitting antenna; the receiver includes: a receiving antenna, two rectifier circuits, a voltage comparator, an information decoding module and an energy management module. In the transmitter: an RF power source is used to output the RF energy required by the system; an RF switch is used to switch the RF energy to the horizontal or vertical polarization port of the transmitting antenna, and the switching polarization loss is small; the transmitting antenna is integrated with the RF switch, and is used to transmit the RF signal to the receiving antenna in the form of an electromagnetic wave with the aforementioned fixed polarization mode switched. In the receiving end: a receiving antenna is used to receive the radio frequency signal of a fixed polarization mode transmitted from the transmitting antenna; two rectifier circuits are respectively connected to the two linear polarization ports of the receiving antenna, and are used to process the radio frequency signal of the corresponding polarization port of the receiving antenna into a DC signal; a voltage comparator is used to compare the voltages of the two rectifier circuits and output the corresponding high and low level information; an information decoding module is used to process the serial port information output by the voltage comparator; an energy management module: used to store the DC energy output by the rectifier circuit, boost the low-voltage DC power to output a stable voltage to allow the device to work normally, and includes a voltage conversion unit, an energy storage unit, and a power management unit.

[0048] The technical principle of the present invention is:

[0049] In the wireless signal-energy simultaneous transmission system, RF switches and polarization reconfigurable antennas are used to control the RF switches by using the transmission information as a control signal, so that the antenna emits a specific polarization wave and contains the information in the polarization. Polarization diversity is successfully used in addition to time diversity, power diversity, and frequency diversity in traditional solutions. The receiving end first converts the RF energy into DC energy through a rectifier circuit, and the received information detects the rectified voltage in a similar way to envelope detection. This method of converting energy first and then processing information integrates energy processing with information processing, which not only improves performance and integration, but also greatly reduces power consumption. The integration of the transmitting antenna and the RF switch and the receiving antenna and the rectifier circuit further improves the integration. The voltage comparator after the two rectifiers can improve the anti-interference ability and reduce the bit error rate. The low power consumption and energy management module make it unnecessary for the receiving end to have additional power supply, and the entire receiving end device can be powered by the transmitting end.

[0050] The various parts in this embodiment are as follows:

[0051] Transmitter configuration:

[0052] RF power source: specifically, a signal generator, which generates a 5.8 GHz RF signal;

[0053] Information sending end: Use a computer to generate the information to be sent and convert it into high and low levels, which serve as control signals input to the RF switch.

[0054] Power amplifier: enhances the transmission capability of the 5.8GHz RF signal generated by the signal generator;

[0055] RF switch: Use MASW-007107 with insertion loss less than 0.5dB and port isolation better than 30dB. Input information can be used as control signals to switch RF signals to different ports of the transmitting antenna. Other RF switches with low insertion loss, high isolation and high switching rate can be used.

[0056] Transmitting antenna: Use a single-frequency high-gain dual-port dual-polarized microstrip antenna, which can effectively transmit 5.8GHz signals. Other single-frequency high-gain dual-polarized antennas can be used.

[0057] Receiver configuration:

[0058] Receiving antenna: Use a single-frequency high-gain dual-port dual-polarized microstrip antenna, which can effectively receive 5.8GHz signals. Other single-frequency high-gain dual-polarized antennas can be used;

[0059] Rectification circuit: Use a 5.8GHz microstrip rectifier with the same operating frequency as the antenna. The topology is a parallel single-tube rectifier circuit. The diode used is HSMS2850, which can suppress high-order harmonics and effectively convert RF signals into DC. Other rectifier circuits with the same operating frequency as the antenna can also be used.

[0060] Energy management module: includes voltage conversion unit, energy storage unit and power management unit, which can make the initial output of the rectifier circuit supply power to the device after a period of energy storage;

[0061] Voltage comparator: A low-power and low-latency voltage comparator is selected and connected to the output port of the rectifier circuit, which can output the correct serial signal by comparing the two rectifier voltages;

[0062] Signal decoding module: uses an MCU with an OLED screen to decode the coded information output by the voltage comparator and display the transmitted information on the OLED screen.

[0063] like Figure 2 and Figure 3 As shown in the figure, this is the working process of the whole system:

[0064] S1: A 5.8 GHz RF signal is generated by a RF power source;

[0065] S2: After being amplified by the power amplifier, the signal is input to the transmitting antenna. The transmitting antenna is a dual-polarization port antenna. Powering different ports will generate electromagnetic waves of different polarizations. The serial port signal generated by the computer using the UART protocol is used to control the single-pole double-throw RF switch to switch the RF energy to the horizontal or vertical polarization port of the transmitting antenna. When the symbol "1" is sent, the serial port outputs a high level, controls the RF switch to switch to the vertical polarization port, and the antenna transmits vertical polarization waves; when the symbol "0" is sent, the serial port outputs a low level, controls the RF switch to switch to the horizontal polarization port, and the antenna transmits horizontal polarization waves. During the switching process, the antenna transmission power remains unchanged, and different polarizations are used to distinguish signals to achieve polarization modulation.

[0066] S3 adjusts the position and angle of the receiving antenna to align it with the polarization of the transmitting antenna. The signal is transmitted over a distance and is received by the receiving antenna.

[0067] The two polarization ports of the S4 receiving antenna are connected to a rectifier. When the symbol "1" is sent, the receiving antenna receives a vertically polarized wave, the rectifier circuit 1 works, and the rectifier circuit 2 does not work; when the symbol "0" is sent, the receiving antenna receives a horizontally polarized wave, the rectifier circuit 2 works, and the rectifier circuit 1 does not work.

[0068] The voltage signal output by a small part of the rectifier circuit S5 is connected to the voltage comparator, the rectifier circuit 1 is connected to the non-inverting input terminal of the voltage comparator, and the rectifier circuit 2 is connected to the reverse input terminal of the voltage comparator;

[0069] The S6 voltage comparator outputs high and low level signals to the information decoding module to decode the information, thereby completing the information transmission of the information link.

[0070] Most of the outputs of the two-way rectifier circuit of S7 are connected to the energy management module, which stores DC energy and boosts the low-voltage DC to output a stable voltage to allow the equipment to work normally, thus completing the simultaneous transmission of information and energy.

[0071] Figure 4 This is a comparison chart of the energy conversion efficiency of the new wireless signal-energy simultaneous transmission system based on polarization modulation in an embodiment of the present invention and a separate wireless energy transmission link without information. The test results show that the two energy conversion efficiency curves almost overlap, with a maximum difference of 1% in the power range of -5 to 15dBm. The test results prove the feasibility and correctness of the design theory of the present invention. The new wireless signal-energy simultaneous transmission method and system based on polarization modulation provided by the present invention can transmit information without reducing energy collection, and can transmit information while maintaining high energy conversion efficiency, and is suitable for multiple communication scenarios of signal-energy simultaneous transmission applications.

[0072] In summary, the present invention proposes a wireless signal and energy transmission system based on polarization modulation, which has the characteristics of rectification before demodulation, can transmit information without reducing the efficiency of energy transmission, and has extremely low power consumption. With the energy management module, the receiving end can work without battery. The working frequency designed in this example is 5.8GHz, which belongs to the open industrial, scientific and medical (ISM) frequency band, and can be applied to the information and energy transmission scenarios of multiple transmission nodes in the Internet of Things.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A wireless energy information cooperative transmission system based on polarization modulation, characterized in that: Including a transmitting end and a receiving end; The transmitting end comprises: A radio frequency power source, used to output the radio frequency signal required by the system; A radio frequency switch, used for switching the radio frequency signal to a horizontal or vertical polarization port; A transmitting antenna, used for transmitting a radio frequency signal switched to a horizontal or vertical polarization port; The receiving end comprises: A receiving antenna, used for receiving the radio frequency signal radiated by the transmitting antenna; Two rectifier circuits are respectively connected to two polarization ports of the receiving antenna to convert the radio frequency signal into a direct current signal; A voltage comparator is used to compare the voltages of the two rectifier circuits; An information decoding module is connected to the output end of the voltage comparator and is used to demodulate the serial port information corresponding to the radio frequency signal; The energy management module is used to store the DC energy output by the two rectifier circuits.

2. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The radio frequency switch is integrated with the transmitting antenna.

3. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The radio frequency switch is a single-pole double-throw type, and its switching is controlled by sending information.

4. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The two rectifier circuits are integrated on the receiving antenna.

5. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The transmitting antenna, receiving antenna and two-way rectifying circuits operate in the same frequency band.

6. The wireless energy information collaborative transmission system according to any one of claims 1 to 5, characterized in that: The transmitting antenna and the receiving antenna are both high-gain dual-port dual-linear polarization antennas.

7. The wireless energy information collaborative transmission system according to any one of claims 1 to 5, characterized in that: The energy management module includes a voltage conversion unit, an energy storage unit and a power management unit.

8. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The two rectifier circuits have the same structure, and their topological structures are both parallel single-tube rectifier circuits.

9. The wireless energy information collaborative transmission system according to claim 1, characterized in that: The information decoding module is specifically an MCU.

10. A method based on the wireless energy information cooperative transmission system according to any one of claims 1 to 9, characterized in that: include: Transmitter: The radio frequency power source transmits a radio frequency signal; The computer uses the UART protocol to generate a serial port signal, which is input into the double-throw port of the RF switch to control the switching of the transmitting antenna polarization; The radio frequency signal is transmitted into free space via the transmitting antenna; Receiver: The receiving antenna receives the radio frequency signal and inputs it into a corresponding rectifier circuit; The rectifier circuit converts the RF signal into a DC signal and outputs the DC signal to the energy management module for powering external devices and completing the energy transmission function; The DC signal generated by the rectifier circuit is simultaneously input into the corresponding in-phase / inverting ports of the voltage comparator to obtain high and low levels representing different code elements, and the high and low levels are input into the information decoding module to complete information transmission.

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