Multi-tone phase shift keying modulation method and receiving device for information energy transfer

Abstract

The invention relates to the field of wireless power transmission, and discloses a multi-tone phase shift keying modulation method and receiving device for information energy transmission, and the device comprises a receiving unit which is used for receiving a multi-tone phase shift keying radio frequency signal; the integrated receiving rectifier is connected with the receiving unit, comprises a matching network, a Schottky diode and a low-pass filter, and is configured to convert the multi-tone phase shift keying radio frequency signal into a direct current output and a baseband frequency signal; and the demodulation unit is connected with the output end of the integrated receiving rectifier and is configured to demodulate symbol information based on the phase of the frequency signal. According to the invention, the power consumption and complexity of the receiving end are reduced, the power conversion efficiency is improved, the output fluctuation can be effectively reduced, the method is suitable for low-power-consumption wireless communication scenes such as Internet of Things terminals, and the dual requirements of wireless information transmission and energy transmission are effectively considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless power transmission, and in particular to a multi-tone phase shift keying modulation method and receiving device for information and energy transmission. BACKGROUND

[0002] With the rapid development of Internet of Things devices and wireless sensor networks, traditional battery-powered solutions face challenges such as endurance and maintenance costs. Radio frequency wireless power transmission technology provides power to devices wirelessly, and cooperates with information transmission to realize synchronous wireless information and energy transmission, which is an important direction for the development of low-power and long-endurance intelligent devices in the future.

[0003] Currently, a separate design scheme is mostly used, and information transmission and energy transmission are optimized separately, resulting in increased system complexity and power consumption. At the same time, the modulation mode of radio frequency signals has a great influence on power conversion efficiency. Although amplitude modulation is easy to demodulate, it causes the voltage ripple at the receiving end to increase, reducing the energy collection efficiency. Therefore, how to design a simple and effective multi-tone phase shift keying modulation method that can ensure reliable information transmission and optimize energy conversion performance has become a technical problem to be solved in the field. SUMMARY

[0004] The purpose of the present application is to provide a multi-tone phase shift keying modulation method and receiving device for information and energy transmission, which solves the technical problem that the prior art cannot transmit information and energy synchronously in the same signal stream, or cannot consider both information transmission and energy transmission.

[0005] Specifically, the present application provides a multi-tone phase shift keying modulation receiving device for information and energy transmission, comprising: a receiving unit for receiving a multi-tone phase shift keying radio frequency signal; an integrated receiving rectifier connected to the receiving unit, comprising a matching network, a Schottky diode and a low-pass filter, configured to convert the multi-tone phase shift keying radio frequency signal into a direct current output and a baseband frequency signal; a demodulation unit connected to the output end of the integrated receiving rectifier, configured to demodulate symbol information based on the phase of the frequency signal.

[0006] A multi-tone phase shift keying modulation receiving method for information and energy transmission is applied to the multi-tone phase shift keying modulation receiving device for information and energy transmission, and the method comprises the following steps: S1, a transmitting end generates non-uniform frequency interval N multi-tone signals, and sets the phase difference of any two adjacent tones to match the phase of a preset information symbol, realizes the modulation and coding of information symbols, and thus forms a multi-tone phase shift keying radio frequency signalx (t); S2, a multi-tone PSK RF signal x (t) is received by an integrated receive rectifier, and an output signal is generated using the integrated receive rectifier y ( t ), the output signal y ( t ) includes a DC power output and a baseband IM2 frequency signal; S3, a demodulation unit demodulates the baseband IM2 frequency signal to obtain information symbols carried thereby.

[0007] The application provided has the beneficial effects of reducing power consumption and complexity of the receiving end, improving power conversion efficiency, and effectively reducing output fluctuation, and is suitable for low-power wireless communication scenarios such as Internet of Things terminals, effectively balancing the dual needs of wireless information transmission and energy transmission. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a device structure schematic diagram of the application; Figure 2 is a structure schematic diagram of the integrated receive rectifier; Figure 3 is a circuit principle schematic diagram of the integrated receive rectifier; Figure 4 is a method flowchart of the application; Figure 5 is a five-tone multi-tone PSK RF input signal spectrum X ( f ) and a rectified baseband output spectrum Y ( f ) diagram. DETAILED DESCRIPTION

[0009] To make the purpose, technical scheme and advantages of the application clearer, the embodiments of the application will be further described below with reference to the drawings.

[0010] Before formally describing the application, the scheme of the application is first described in a general way for easy understanding.

[0011] Please refer to Figure 1 , Figure 1 is a device structure schematic diagram.

[0012] The application is a multi-tone PSK modulation receiving device for information and energy transmission, comprising: a receiving unit for receiving a multi-tone PSK RF signal; It should be noted that the receiving unit in the application is used to receive a multi-tone PSK RF signal.

[0013] The integrated receiving rectifier is connected with the receiving unit, and includes a matching network, a Schottky diode and a low-pass filter, which are configured to convert the multi-tone phase shift keying radio frequency signal into a direct current output and a baseband IM2 frequency signal. Specifically, refer to Figures 2-3 , Figure 2 It is a structural schematic diagram of the integrated receiving rectifier. Figure 3 It is a circuit principle schematic diagram of the integrated receiving rectifier.

[0014] The matching network is composed of a capacitor C1, first to sixth microstrip transmission lines, a first open-circuit branch and a second open-circuit branch; the Schottky diode includes a first Schottky diode D1 and a second Schottky diode D2; and the low-pass filter includes a parallel capacitor C out and a load resistor R load .

[0015] The input multi-tone phase shift keying radio frequency signal is transmitted to the first open-circuit branch and the second open-circuit branch through the first microstrip transmission line and the capacitor C1; the second open-circuit branch is electrically connected to the negative electrode of the first Schottky diode D1 and the positive electrode of the second Schottky diode D2, respectively; the negative electrode of the second Schottky diode D2 is connected to one end of the third microstrip transmission line and one end of the fourth microstrip transmission line, respectively; the other end of the fourth microstrip transmission line is connected to one end of the load resistor R load and an output signal end; the other end of the load resistor R load is connected to the sixth microstrip transmission line followed by grounding; the other end of the third microstrip transmission line is connected to the parallel capacitor C out and the fifth microstrip transmission line followed by grounding in sequence; and the positive electrode of the first Schottky diode D1 is connected to the second microstrip transmission line followed by grounding.

[0016] The demodulation unit is connected to the output end of the integrated receiving rectifier and is configured to demodulate symbol information based on the phase of the frequency signal.

[0017] It should be noted that the lengths of the first open-circuit branch and the second open-circuit branch are designed to achieve a 100MHz matching bandwidth at a frequency point of 2.45GHz.

[0018] It should be noted that the second microstrip transmission line, the fifth microstrip transmission line and the sixth microstrip transmission line are used for impedance transition.

[0019] It should be noted that the low-pass filter is designed to have a larger low-pass filter bandwidth than the highest relevant IM2 frequency component, but smaller than the base frequency of the radio frequency.

[0020] Please refer to Figure 4 , Figure 4 It is a flowchart of the method.

[0021] A multi-tone phase shift keying modulation receiving method for information energy transmission, applied to the multi-tone phase shift keying modulation receiving device for information energy transmission, comprising the following steps: S1, the sending end generates a non-uniform frequency interval N Multi-tone signal, and sets the phase difference of any two adjacent tones of the multi-tone signal to match the preset information symbol phase, realizes the modulation coding of the information symbol, and thus forms a multi-tone phase shift keying radio frequency signal x (t); It should be noted that the sending end can adopt a radio frequency sending circuit, which can adopt an existing structure, which is not the focus of the present application, and is not limited by this.

[0022] S2, the multi-tone phase shift keying radio frequency signal x (t) is received by an integrated receiving rectifier, and an output signal y ( t ) is generated by the integrated receiving rectifier; y ( t ) includes a direct current power output and a baseband IM2 frequency signal; S3, the demodulation unit demodulates the baseband IM2 frequency signal to obtain the information symbol carried thereby.

[0023] Specifically, x ( t ) is composed of a center frequency f c 2.45GHz. After the rectifier, N ( x , t ) generates a baseband output signal y ( t ).

[0024] It should be noted that the demodulation unit adopts a frequency component phase extraction algorithm based on Fourier transform, and the corresponding hardware structure implementation can be realized by using an ADC + digital processor (such as FPGA / MCU) and the like, which is not the focus of the present application, and is only used for explanation and description, and is not limited by this.

[0025] In step S1, the expression of the multi-tone phase shift keying radio frequency signal x (t) is as follows:

[0026] y ( t ) is used for both power transmission and information decoding. The complete y ( tThis is used for wireless power transmission, and also for decoding phase information from some baseband tones. Please refer to... Figure 5 , Figure 5 It is the spectrum of the five-tone multi-tone phase shift keying radio frequency input signal. X ( f and rectified baseband output spectrum Y ( f )picture.

[0027] Output signal in step S2 y ( t As shown in the following formula:

[0028] in, y dc DC power output, f n For the first n The frequency of each tone signal For the first n The phase of each tone signal; A n For the first n The amplitude of each tone signal.

[0029] In this invention, a modulation scheme is designed using the nonlinear characteristics of an integrated receiver rectifier.

[0030] IM2s is by N -tone is produced by mixing two tones in a polyphonic system.

[0031] In this invention, information is transmitted between consecutive tones with the phase of IM2s. The transmitted signal x(t) is considered as: (1) In the formula, A and φ n They represent the first n audio rate f n The amplitude and phase. Consider. N =3 in the three-tone case of (1).

[0032] After transmitting the three-tone multi-pitch signal via the flowchart, the filtered output signal is obtained. y ( t It consists of a combination of DC and baseband intermodulation frequency components. All harmonic and odd-order intermodulation components are filtered out by a low-pass filter. In the baseband tone, IM2 is more prominent than higher-order harmonic components such as the fourth and sixth harmonics. y ( t ) can be used y dc And IM2s are represented as

[0033] Where A1, A2, and A3 represent IM2 in (f 2 -f 1 ) , (f 3 -f 2 ) and (f 3 -f 1 ) The amplitude at that point. In this invention, information exists only in the form of IM2 phase between consecutive tones, i.e. (f 2 -f 1 ),(f 3 -f 2 ),…,(f N -f N−1 ) Pitch and phase carry information. The five-tone multi-tone phase shift keying radio frequency signal x(t) generates a baseband signal composed of various intermodulation frequency components, among which four IM2 frequency components generated by intermodulation between consecutive frequencies are used for phase information detection.

[0034] In order to transmit multi-tone signals in a single transmission ( N -1) symbols, when selecting fns, to ensure that (N−1) IM2s between consecutive frequencies do not overlap, nor do they coincide with other non-consecutive IM2s. Multitone f n s In (1), the intervals cannot be uniform, and Δ needs to be appropriately selected. f n The first tone phase shift keying signal n Each audio frequency can be expressed as

[0035] In the formula Indicates the nth note and The frequency interval between each note. To distinguish the required continuous frequency generation of multi-tone phase shift keying signals IM2s, and must satisfy,

[0036] in express ixi An upper triangular matrix of order X, whose non-zero elements are 1.

[0037] and It is a column vector.

[0038] Multi-tone phase shift keying is considered to have a center frequency as the center, is considered to be s the greatest common divisor (GCD) between them.

[0039] Bandwidth spreading factor r for the signal to have a minimum bandwidth (r=0) and a wider bandwidth (r>0) under certain N The overall signal bandwidth is not only a factor of N but also depends on the selected values of GCD and r For example, for N=5, =2.45GHz, GCD=1MHz, r =0, the s of algorithm 1 is 1, 2, 4, 5MHz. The corresponding multi-tone phase shift keying signal x(t) will have tones of 2.444, 2.445, 2.447, 2.451 and 2.456GHz. After passing the rectifier, the baseband signal produces GCD=1MHz, which has various IM frequency components with at least 1MHz spacing. The 1, 2, 4 and 5MHz 4 IM frequencies are used for information detection. increases with the increase of GCD or r However, the bandwidth of the rectifier match and the cutoff frequency of the low pass filter ( ) impose restrictions on the allowed multi-tone N , GCD and r to achieve proper wireless power transfer.

[0040] Please refer to Table 1, which is the pseudo code of multi-tone phase shift keying frequency control.

[0041]

[0042] For phase shift keying polyphase, from equation (2), the output baseband tone phase is the phase difference between the corresponding multi-tone frequencies. In multi-tone phase shift keying, the symbol is encoded as the phase difference of consecutive tones. The first phase n φ n The information symbol can be transmitted as:

[0043] Assume the first tone phase =0. In equation (7), represents the information symbol, and ​​differential transmission.

[0044] Let and be the lower and upper bounds of the symbol constellation, - 1) and = δ, where δ is defined as the considered phase range for allocating information symbols within this range. Thus, the available information symbol set S containing M symbols can be defined as: M S

[0045] with and modulation order M . The M information symbols transmitted on the multi-tone PSK signal belong to this available information symbol set S. N Assuming the symbols are equidistant and symmetric to the x-axis, i.e. , equation (8) can be rewritten as:

[0046]

[0047] Thus, for δ = [-90°, 90°] and M = 4, the available symbol phase set S is 67.5°, 22.5°, -22.5° and -67.5°, each symbol carrying bits.

[0048] The actual possible single tone phase is different from the transmitted symbol selected from S, because the phase of each tone has a different selection, as shown in equation (7), which varies according to δ and M. Assuming is zero, there can be its phase

[0049] At M = 4 and δ = [-90°, 90°]. Further, from equation (7), it can be seen that can be regarded as a combination of two symbols.

[0050]

[0051] where and are the signs of the constellation points defined in equation (9). Equation (11) can be rewritten as: M

[0052] In summary, has ( n - 1)​​​​​​M - n -2) combined, its range of variation is [-( n -1)( M -1)(δ / 2 M ),( n -1)( M -1)(δ / 2 M The phase combination of equation (7) in a specific first phase. n Once the pitch is satisfied, the repeat begins.

[0053]

[0054] The above method receives multi-tone phase-shift keying (PSK) radio frequency signals, converts them into DC output and baseband IM2 frequency signals via an integrated receiver rectifier, and then demodulates the information symbols based on the phase of the IM2 frequency using a demodulation unit. Efficient information encoding and decoding are achieved through the non-uniform frequency spacing of the multi-tone signals and the phase difference between adjacent tones, while ensuring effective transmission of radio frequency energy.

[0055] The integrated receiver rectifier design includes: Design a low-power integrated receiver rectifier circuit that generates DC and baseband outputs in response to RF input signals. The phase of the IM2 frequency component in the baseband is used as the basis for information decoding, eliminating the need for a traditional RF local oscillator and significantly reducing receiver power consumption.

[0056] Specifically, the integrated receiver rectifier structure consists of an input matching network of C1=1pF, two Schottky diodes, and a low-pass filter (C1=1pF). out =0.1pF,R load Composed of (4.4kΩ).

[0057] It should be noted that, Figure 3 The values ​​or ranges shown are only intended to demonstrate the feasibility of using the proposed multi-tone phase shift keying for synchronizing wireless information and energy transfer operations, and are not intended to impose any limitations.

[0058] According to the reflectance coefficient (S) 11 By using C1, stub length, transmission line length, and R load This rectifier is designed to maximize power conversion efficiency over a relatively large matching bandwidth (BW) (approximately 100 MHz, centered at 2.45 GHz). The rectifier model is designed with wireless power transfer and wireless information transmission in mind.

[0059] In the rectifier design, the low pass filter cutoff frequency should be chosen to ensure that all harmonics are filtered out by the low pass filter while it should have enough bandwidth to pass the relevant IM2 baseband information tone. The rectifier is designed to have a low pass filter bandwidth larger than the highest relevant IM2 frequency component but smaller than the base frequency of the radio frequency. So that the resulting signal has a bandwidth smaller than the radio frequency bandwidth. The GCD and N .

[0060] The overall synchronized wireless information and energy transfer performance of the multi-tone PSK signal is analyzed. The wireless information transfer and wireless energy transfer performance of the multi-tone PSK signal is measured from the achievable power conversion efficiency and BER respectively. The power conversion efficiency at the output can be defined as:

[0061] The transmit power of the multi-tone PSK signal x ( t ) and the DC voltage of the received signal ( y ) and the received signal t ( ) are represented. The power conversion efficiency at the output varies according to the peak to average power ratio of the multi-tone PSK signal.

[0062] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-tone phase-shift keying modulation receiving device for information energy transmission, characterized in that: include: The receiving unit is used to receive multi-tone phase shift keying radio frequency signals; An integrated receiver rectifier, connected to the receiving unit, includes a matching network, a Schottky diode, and a low-pass filter, configured to convert multi-tone phase-shift keying radio frequency signals into DC output and baseband. Frequency signal; The demodulation unit, connected to the output of the integrated receiver rectifier, is configured to be based on the... Phase demodulation symbol information of frequency signals.

2. The multi-tone phase shift keying modulation receiving device for information energy transmission as described in claim 1, characterized in that: The matching network consists of capacitor C1, first microstrip transmission lines to sixth microstrip transmission lines, a first open-circuit stub, and a second open-circuit stub; the Schottky diodes include: a first Schottky diode D1 and a second Schottky diode D2; the low-pass filter includes: a parallel capacitor C out and load resistance R load .

3. The multi-tone phase shift keying modulation receiving device for information energy transmission as described in claim 2, characterized in that: The input multi-tone phase-shift keying radio frequency signal is transmitted via a first microstrip transmission line and capacitor C1 to a first open-circuit stub and a second open-circuit stub. The second open-circuit stub is electrically connected to the cathode of the first Schottky diode D1 and the anode of the second Schottky diode, respectively. The cathode of the second Schottky diode D2 is connected to one end of the third microstrip transmission line and one end of the fourth microstrip transmission line, respectively. The other end of the fourth microstrip transmission line is connected to the load resistor R. load One end and the output signal terminal; load resistor R load The other end of the third microstrip transmission line is connected to ground after being connected to the sixth microstrip transmission line; the other end of the third microstrip transmission line is connected in parallel to capacitor C. out And the fifth microstrip transmission line is grounded; the positive terminal of the first Schottky diode D1 is connected to the second microstrip transmission line and then grounded.

4. The multi-tone phase shift keying modulation receiving device for information energy transmission as described in claim 3, characterized in that: The lengths of the first open-circuit stub and the second open-circuit stub are designed to achieve a 100MHz matching bandwidth at the 2.45GHz frequency point.

5. The multi-tone phase shift keying modulation receiving device for information energy transmission as described in claim 3, characterized in that: The second, fifth, and sixth microstrip transmission lines are used for impedance transition.

6. The multi-tone phase shift keying modulation receiving device for information energy transmission as described in claim 3, characterized in that: The low-pass filter is designed to have a larger low-pass filter bandwidth than the highest correlated IM2 frequency component, but smaller than the radio frequency fundamental frequency.

7. A multi-tone phase-shift keying modulation receiving method for information power transmission, applied to the multi-tone phase-shift keying modulation receiving device for information power transmission as described in any one of claims 1 to 6, characterized in that: The method includes the following steps: S1. The transmitting end generates a non-uniform frequency spacing. N A multi-tone signal is generated, and the phase difference between any two consecutive adjacent tones of the multi-tone signal is set to match the phase of a preset information symbol, thereby achieving modulation and coding of the information symbol, thus forming a multi-tone phase-shift keying radio frequency signal. x (t); S2, Multi-tone Phase Shift Keying Radio Frequency Signal x (t) Received by the integrated receiver rectifier, and the output signal is generated using the integrated receiver rectifier. y ( t ), output signal y ( t This includes DC power output and baseband IM2 frequency signal; S3. The demodulation unit demodulates the baseband IM2 frequency signal to obtain the information symbols it carries.

8. The multi-tone phase shift keying modulation receiving method for information energy transmission as described in claim 7, characterized in that: The multi-tone phase shift keying radio frequency signal mentioned in step S1 x ( t By precisely defining the frequency interval, it is ensured that the baseband intermodulation frequency IM2 components at the output end do not overlap, thus achieving... N -1 The phase difference between consecutive frequencies carries information.

9. A multi-tone phase shift keying modulation receiving method for information energy transmission as described in claim 7, characterized in that: The demodulation unit employs a frequency component phase extraction algorithm based on Fourier transform.

10. A multi-tone phase shift keying modulation receiving method for information energy transmission as described in claim 7, characterized in that: In step S1, the multi-tone phase shift keying radio frequency signal x The expression for (t) is as follows: Output signal in step S2 y ( t As shown in the following formula: in, y dc DC power output, f n For the first n The frequency of each tone signal For the first n The phase of each tone signal; A n For the first n The amplitude of each tone signal.

Images