Metasurface-based MIMO transceiver system

Abstract

The application provides a kind of MIMO transceiver systems based on super surface, it is characterized in that, including: horn antenna, transceiver isolation switch, receiving link, transmitting link, intermediate frequency digital signal processing module, digital controller and super surface;The horn antenna is connected with transceiver isolation switch, the transceiver isolation switch is connected with receiving link and transmitting link, the receiving link and transmitting link are connected with intermediate frequency digital signal processing module, the digital controller is connected with intermediate frequency digital signal processing module and super surface.This application utilizes super surface and single horn feed antenna after single radio frequency transceiver link to realize MIMO transceiver function simultaneously, overcome the limitation that super surface itself cannot handle multi-user signal, and the maximum single antenna user number that provides transceiving information service is same with super surface unit number.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication and new artificial electromagnetic material, in particular to a MIMO transceiver system based on metasurface. BACKGROUND

[0002] Multiple-input multiple-output (MIMO) technology is one of the key technologies in multi-antenna communication. Without increasing bandwidth and total power, MIMO technology can effectively counteract the influence of spatial channel fading, significantly improve the frequency efficiency and channel capacity of the communication system, and is widely used in the field of wireless communication. However, in large-scale MIMO technology, multiple antenna systems generally require multiple sets of radio frequency transceiver links, and therefore face significant challenges in terms of cost, size, power consumption, and integration.

[0003] New artificial electromagnetic surfaces, also known as metasurfaces, are composed of periodically arranged electromagnetic units. By optimizing the structure, size, and other parameters of the units, electromagnetic wave regulation and control functions that are different from conventional electromagnetic materials can be achieved, providing new ideas for wireless communication hardware architecture based on direct radio frequency regulation. However, metasurfaces generally use only a single horn antenna for spatial feeding or signal reception, and are limited by a single transmit / receive chain. Therefore, metasurfaces themselves cannot simultaneously implement multi-user transceiving functions, and are often used as passive relay stations for scattering communication or transmitters for radio frequency direct modulation. One of the main difficulties is how to realize independent transceiving devices based on metasurfaces. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a MIMO transceiver system based on metasurface.

[0005] According to the MIMO transceiver system based on metasurface provided by the present application, the system comprises a horn antenna, a transceiving isolation switch, a receiving chain, a transmitting chain, an intermediate frequency digital signal processing module, a digital controller, and a metasurface. The horn antenna is connected to the transceiving isolation switch, the transceiving isolation switch is connected to the receiving chain and the transmitting chain, the receiving chain and the transmitting chain are connected to the intermediate frequency digital signal processing module, and the digital controller is connected to the intermediate frequency digital signal processing module and the metasurface.

[0006] The metasurface comprises N periodically arranged electromagnetic regulation micro-units, and the electromagnetic regulation micro-units are of reflective, transmissive, or reflective / transmissive adjustable structure.

[0007] The digital controller generates a corresponding periodic digital control signal according to a periodic modulation timing sequence, and controls the intermediate frequency digital signal processing module to complete the receiving and transmitting signal processing procedures.

[0008] The electromagnetic regulation micro-unit periodically regulates the phase or amplitude of reflected electromagnetic waves or transmitted electromagnetic waves under the control of a digital controller.

[0009] The transceiving isolating switch selects the receiving link and the transmitting link in time, and corresponds to two working modes of receiving mode and transmitting mode respectively.

[0010] Preferably, the radio frequency receiving link comprises a low noise amplifier, a mixer and an analog-to-digital converter connected in sequence, and a radio frequency local oscillator connected with the mixer; the radio frequency receiving link amplifies the receiving signal strength from the horn antenna, and converts the radio frequency signal to a digital signal after down-conversion to an intermediate frequency.

[0011] Preferably, the radio frequency transmitting link comprises a digital-to-analog converter, a mixer and a power amplifier connected in sequence, and a radio frequency local oscillator connected with the mixer; the radio frequency transmitting link converts the digital signal to an analog signal, and up-converts the intermediate frequency signal to a radio frequency after power amplification, and radiates out by the horn antenna.

[0012] Preferably, the intermediate frequency digital signal processing module comprises an intermediate frequency digital local oscillator, a digital mixer and a harmonic processing module; the intermediate frequency digital signal processing module realizes the mapping between the multi-user signals and 2Q+1 harmonics through the orthogonal digital down-conversion and the orthogonal digital up-conversion and the harmonic processing module.

[0013] The digital mixer is provided with 2Q+1, and the center frequencies are f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p , wherein f0 is the center frequency of analog down-conversion, f p is the frequency of the periodic amplitude and phase adjustment of the super surface; the digital mixer orthogonally down-converts the selected 2Q+1 harmonics to the baseband in the receiving mode, and up-converts the pre-coded 2Q+1 baseband signals to the corresponding harmonic intermediate frequencies in the transmitting mode.

[0014] The harmonic processing module performs channel estimation and MIMO detection on the 2Q+1 baseband harmonic signals in the receiving mode, and demodulates and outputs the information transmitted by the user; in the transmitting mode, the multi-user baseband modulation signal is mapped to 2Q+1 harmonic baseband signals through pre-coding.

[0015] Preferably, the receiving mode comprises the following steps:

[0016] Step S1: The transceiving isolating switch selects the receiving link, receives the incoming wave signal in space through the periodic amplitude and phase modulation of the super surface, receives by the horn antenna, and transmits to the intermediate frequency digital signal processing module through the down-conversion and intermediate frequency sampling of the receiving link.

[0017] Step S2: The single-channel intermediate frequency digital signal received by the intermediate frequency digital signal processing module contains periodic modulation introduced infinite harmonic signals, and 2Q+1 digital mixers are used to digitally quadrature down-convert the harmonic signals with center frequencies f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p to the baseband; assuming that the received signal contains k single-transmit-antenna user signals, then at the baseband, the qth harmonic signal model is:

[0018]

[0019] where K is the number of served users, K≤N≤2Q+1, E k and s k are the transmit power and transmit baseband symbol signal of the kth user, h n,k is the channel response between the nth metasurface unit and the kth user, p n,q is the fixed near-field channel response of the horn antenna to the nth metasurface unit at the qth harmonic frequency f c +qf p , which is obtained by calibration measurement, where f c is the incoming radio frequency center frequency, is the Fourier coefficient of the qth harmonic of the receiving mode of the nth metasurface unit, which is given by:

[0020]

[0021] where is the equivalent periodic modulation function of the periodic amplitude and phase modulation of the nth metasurface unit in the receiving mode;

[0022] Step S3: The harmonic processing module jointly down-converts the 2Q+1 baseband harmonics based on the harmonic signal model, performs channel estimation based on the baseband harmonic signals, and detects and demodulates the output multi-user signals from the baseband harmonic signals, assuming that the estimated channel response is the MIMO detection vector of the kth user is

[0023] g k =[g -Q,k ,g -Q+1,k ,...,g Q-1,k ,g Q,k ]

[0024] then the detected output signal of the kth user is

[0025]

[0026] Preferably, the transmitting mode comprises the following steps:

[0027] Step A1: The harmonic processing module uses the channel response estimated by the receiving mode to map the baseband signals of K users into 2Q+1 signals through harmonic-based precoding, K≤N≤2Q+1, which correspond to 2Q+1 baseband harmonic signals respectively, and let the beamforming vector of the kth user after precoding be:

[0028]

[0029] Then the qth (Q≤q≤Q) transmitting signal after harmonic-based precoding is represented as:

[0030]

[0031] Where s k is the baseband signal transmitted to the kth user;

[0032] Step A2: In the intermediate frequency digital signal processing module, use 2Q+1 digital mixers to digitally quadrature up-convert the 2Q+1 signals after harmonic precoding to f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p frequencies respectively, and synthesize an intermediate frequency signal containing 2Q+1 harmonics;

[0033] Step A3: The transceiver isolation switch selects the receiving link, and the synthesized single digital intermediate frequency signal is up-converted to radio frequency through the receiving link and is incident to the metasurface through the horn antenna. After the periodic amplitude and phase modulation of the metasurface, it is radiated into space. Among them, the signal at the center frequency f c contains user precoding information and is regarded as a useful signal. Let the kth user use a single antenna to receive the signal, and the useful signal received at the kth user is represented as

[0034]

[0035] Where is the Fourier coefficient of the qth harmonic of the transmitting mode of the nth metasurface unit, which is given by

[0036]

[0037] Where is the equivalent periodic modulation function of the periodic amplitude and phase modulation of the nth metasurface unit in the transmitting mode.

[0038] Preferably, the equivalent periodic modulation function of the metasurface unit in the transmitting mode or the receiving mode is selected according to the following standard: 2Q+1 harmonic signals selected before or after modulation are independent of each other, and the frequency of the periodic amplitude and phase modulation is greater than the maximum bandwidth B of the transceiving baseband signal max satisfying the following formula:

[0039] f p ≥B max .

[0040] Preferably, the metasurface periodic amplitude and phase modulation frequency f p After the determination, the selected -Qth to Qth harmonic signals can be replaced by any 2Q+1 different harmonic signals, the selected 2Q+1 harmonic signals are independent of each other, and Q satisfies 2Q+1≥N≥K.

[0041] Preferably, the N periodically arranged electromagnetic regulation micro-units of the metasurface are divided into N0 sub-arrays to realize MIMO transceiving function, and the selection of the number of harmonics, the number of sub-arrays and the number of users served is limited by K≤N0≤2Q+1.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] 1. The present application uses a metasurface and a single radio frequency transceiving link behind a single horn feed antenna to simultaneously realize MIMO transceiving function, overcoming the limitation that the metasurface itself cannot handle multiple user signals, and providing a maximum number of single antenna users for transceiving information service, which is the same as the number of metasurface units;

[0044] 2. The overall architecture of the system is simple, low in cost, low in power consumption and small in size. The present application is based on a metasurface with periodic amplitude and phase regulation, and only uses a single transceiving link behind a single horn antenna for communication, without the multiple radio frequency transceiving links in the traditional MIMO communication architecture, so the overall hardware architecture is simple and low in complexity, overcoming the limitations of large-scale MIMO transceivers in terms of cost, power consumption and size;

[0045] 3. The metasurface of the present application dynamically regulates the transceiving electromagnetic waves, and the number of transceiving channels can be flexibly configured, and the digital domain processing can also be flexibly changed accordingly. The periodic regulation mode, the number of transceiving channels and the number of harmonics in the digital domain frequency conversion can be flexibly changed according to the number of users served and the user channel information, and the hardware does not need to be changed during the switching process, only the software control logic of the digital controller needs to be changed. BRIEF DESCRIPTION OF DRAWINGS

[0046] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0047] Figure 1 A schematic diagram of a super surface based MIMO transceiver system of the present application;

[0048] Figure 2 A schematic diagram of a single channel modulated signal spectrum modulated by a super surface periodically in a receiving mode;

[0049] Figure 3 A constellation diagram of four user signals outputted after channel estimation and MIMO demodulation by extracted baseband harmonic signals in a digital domain in a receiving mode;

[0050] Figure 4 A schematic diagram of a radio frequency transmission signal spectrum after baseband harmonic signal precoding and different harmonic intermediate frequency mixing fed into a horn antenna in a transmitting mode.

[0051] BRIEF DESCRIPTION OF DRAWINGS

[0052] horn antenna 1 analog to digital converter 8

[0053] transceiver isolation switch 2 digital to analog converter 9

[0054] low noise amplifier 3 digital mixer 10

[0055] power amplifier 4 intermediate frequency digital local oscillator 11

[0056] radio frequency local oscillator 5 harmonic processing module 12

[0057] mixer 6 digital controller 13

[0058] super surface 7 intermediate frequency digital signal processing module 14 DETAILED DESCRIPTION

[0059] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of changes and improvements can be made. These are within the scope of the present application.

[0060] The present application discloses a super surface based MIMO transceiver system, comprising: a horn antenna 1, a transceiver isolation switch 2, a receiving link, a transmitting link, an intermediate frequency digital signal processing module 14, a digital controller 13 and a super surface 7; the horn antenna 1 is connected with the transceiver isolation switch 2, the transceiver isolation switch 2 is connected with the receiving link and the transmitting link, the receiving link and the transmitting link are connected with the intermediate frequency digital signal processing module 14, and the digital controller 13 is connected with the intermediate frequency digital signal processing module 14 and the super surface 7.

[0061] The metasurface 7 comprises N periodically arranged electromagnetic modulation micro-units, which are reflective, transmissive or reflective / transmissive adjustable structures;

[0062] The digital controller 13 generates a corresponding periodic digital control signal according to a periodic modulation timing, and controls the intermediate frequency digital signal processing module 14 to complete a receiving and transmitting signal processing procedure;

[0063] The electromagnetic modulation micro-units periodically adjust the phase or amplitude of reflected electromagnetic waves or transmitted electromagnetic waves under the control of the control signal of the digital controller 13;

[0064] The transceiver isolation switch 2 selects a receiving link and a transmitting link in time, corresponding to two working modes of a receiving mode and a transmitting mode.

[0065] The radio frequency receiving link comprises a low noise amplifier 3 (LNA), a mixer 6 and an analog-to-digital converter 8 (ADC) connected in sequence, and a radio frequency local oscillator 5 (LO) connected with the mixer 6; the radio frequency receiving link amplifies the receiving signal strength from the horn antenna 1, and converts the intermediate frequency signal into a digital signal after down-conversion.

[0066] The radio frequency transmitting link comprises a digital-to-analog converter 9 (DAC), a mixer 6 and a power amplifier 4 (PA) connected in sequence, and a radio frequency local oscillator 5 (LO) connected with the mixer 6; the radio frequency transmitting link converts the digital signal into an analog signal, and up-converts the intermediate frequency signal to a radio frequency, and radiates it out by the horn antenna 1 after power amplification.

[0067] The intermediate frequency digital signal processing module 14 comprises an intermediate frequency digital local oscillator 11 (NCO), a digital mixer 10 and a harmonic processing module 12; the intermediate frequency digital signal processing module 14 realizes the mapping between the multi-user signal and 2Q+1 harmonics through the orthogonal digital down-conversion and the orthogonal digital up-conversion and the harmonic processing module 12;

[0068] The digital mixer 10 is provided with 2Q+1, and the center frequencies are f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p , wherein f0 is the center frequency of analog down-conversion, f p is the frequency of periodic amplitude and phase adjustment of the metasurface 7; the digital mixer 10 orthogonally down-converts the selected 2Q+1 harmonics to the baseband in the receiving mode, and up-converts the 2Q+1 baseband signals after precoding to the corresponding harmonic intermediate frequency in the transmitting mode;

[0069] The harmonic processing module 12 performs channel estimation and MIMO detection on 2Q+1 baseband harmonic signals in the receiving mode and demodulates the information transmitted by the user to output; in the transmitting mode, the multi-user baseband modulation signal is mapped to 2Q+1 harmonic baseband signals through precoding.

[0070] For the receiving mode or the transmitting mode, the N super surface 7 units perform periodic amplitude and phase modulation in the transmitting mode or the receiving mode. The equivalent periodic modulation function selection standard is that the selected 2Q+1 harmonic signals from-Q to Q before or after modulation are independent of each other, and the frequency f p The maximum bandwidth B max satisfies the following formula:

[0071] f p ≥B max

[0072] For the receiving mode or the transmitting mode, the N super surface 7 units perform periodic amplitude and phase modulation in the transmitting mode or the receiving mode. The equivalent periodic modulation function selection standard is that the selected 2Q+1 harmonic signals from-Q to Q before or after modulation are independent of each other, and the frequency f p After determination, the selected-Q to Q harmonic signals can be replaced by any 2Q+1 harmonic signals with different harmonic frequencies, but the selected 2Q+1 harmonic signals need to be independent of each other, and Q satisfies 2Q+1≥N≥K;

[0073] For the receiving mode or the transmitting mode, the N super surface 7 units can be divided into N0 sub-arrays to realize MIMO transceiver function, and the selection of the number of harmonics, the number of sub-arrays and the number of users served is limited to K≤N0≤2Q+1;

[0074] Embodiment 2:

[0075] The receiving mode includes the following steps:

[0076] Step S1: The transceiver isolation switch 2 selects the receiving link, the incoming wave signal in space is received by the horn antenna 1 through the periodic amplitude and phase modulation of the super surface 7, and is sent into the intermediate frequency digital signal processing module 14 through the receiving link down conversion and intermediate frequency sampling; here, combined with the amplitude and phase adjustment characteristics of the super surface 7, the selected periodic adjustment method is: with a certain modulation period, the phase of the incoming wave signal is periodically switched between 0 and 180 degrees, and each phase state maintains a certain time sequence duty ratio, that is, the expression of the equivalent periodic modulation function in the mth modulation period is

[0077]

[0078] It should be noted that the above super surface 7 modulation method and modulation function are only an example, and different modulation methods and modulation functions that meet the function can be applied according to different application requirements and optimization goals. Assuming that the number of super surface 7 units is 18x18, which is uniformly divided into 9 sub-arrays, the modulation functions of the units in the sub-arrays are the same, the modulation functions described above are used between the sub-arrays, the modulation frequency is 20MHz, the super surface 7 periodically modulates and receives 4 single-antenna user signals, the radio frequency carrier frequency is 5.8GHz, and the baseband modulation mode is 16QAM, Figure 2 The spectrum of the single radio frequency modulated signal received by the horn antenna 1 after the periodic modulation of the super surface 7 is given. It can be seen from the figure that after the periodic phase adjustment of the super surface 7, the radio frequency signal received by the horn antenna 1 contains harmonic signals with a frequency interval of 20MHz in addition to the base frequency signal at the carrier frequency 5.8GHz. The single signal containing harmonics is down-converted to an intermediate frequency and sampled to a digital domain for further processing;

[0079] Step S2: The single intermediate frequency digital signal received by the intermediate frequency digital signal processing module 14 contains infinite harmonic signals introduced by periodic modulation, and 2Q+1 digital mixers 10 are used to digitally quadrature down-convert the harmonic signals with center frequencies f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p to the baseband. Assuming that the received signal contains k single-transmit-antenna user signals, the qth harmonic signal model at the baseband is:

[0080]

[0081] Where K is the number of users served, K≤N≤2Q+1, E k and s k are the transmit power and transmit baseband symbol signal of the kth user, h n,k is the channel response between the nth super surface 7 unit and the kth user, p n , q is the fixed near-field channel response of the horn antenna 1 to the nth super surface 7 unit at the qth harmonic frequency f c +qf p , which is obtained by calibration measurement, where f c is the center frequency of the incoming radio frequency, is the Fourier coefficient of the qth harmonic of the reception pattern of the nth super surface 7 unit, which is given by:

[0082]

[0083] Where An equivalent periodic modulation function of the nth metasurface 7 unit in the receiving mode of periodic amplitude-phase modulation;

[0084] For Figure 2 The single-path radio frequency receiving modulation signal spectrum, considering the number of users K = 4, the number of subarrays N0 = 9, Q = 4 can be selected, that is, using 9 digital mixers 10, the intermediate frequency frequency is 5.72GHz~5.88GHz, and the harmonic signals (corresponding to the harmonic components marked -4~4 in the figure) with an interval of 20MHz are digitally quadrature down-converted to the baseband;

[0085] Step S3: The harmonic processing module 12 jointly down-converts the 2Q+1 baseband harmonic signals based on the harmonic signal model, performs channel estimation based on the baseband harmonic signals using the known training sequence, and detects and demodulates the output multi-user signals from the baseband harmonic signals using the harmonic-based MIMO detection method; let the estimated channel response be The MIMO detection vector of the kth user is

[0086] g k =[g -Q,k ,g -Q+1,k ,...,g Q-1,k ,g Q,k ]

[0087] Then the output signal of the kth user is detected

[0088]

[0089] For the 9 harmonics down-converted by the digital quadrature down-conversion in step S2, Figure 2 The 9 harmonics can be jointly used to perform channel estimation using the least square method (LS) through the known channel estimation code sequence and the received baseband harmonic signal code sequence. After completing the channel estimation, the channel information can be used to calculate the MIMO detection vector of the zero-forcing (ZF), and the baseband harmonic signals are combined to detect and demodulate the signals of the four users, and the constellation diagrams of the four users are as shown in Figure 3 The signals of the four users are normally demodulated and output, and the constellation symbols are the same as the symbols transmitted by each user at the transmitting end. It should be pointed out that the harmonic signal receiving model in step S2 can also use various channel estimation methods and MIMO detection methods. Here, LS and ZF methods are used as examples to illustrate the specific process and results of channel estimation and MIMO detection.

[0090] Embodiment 3

[0091] The transmitting mode includes the following steps:

[0092] Step A1: The harmonic processing module 12 uses the channel response estimated by the receiving mode to map the baseband signals of K users into 2Q+1 signals through harmonic-based precoding, K≤N≤2Q+1, which correspond to 2Q+1 baseband harmonic signals respectively, and let the beamforming vector of the kth user after precoding be:

[0093]

[0094] Then the qth (Q≤q≤Q) transmission signal after harmonic-based precoding is represented as:

[0095]

[0096] Where s k is the baseband signal transmitted to the kth user.

[0097] Step A2: In the intermediate frequency digital signal processing module 14, use 2Q+1 digital mixers 10 to respectively digitally quadrature up-convert the 2Q+1 signals after harmonic precoding to f0-Qf p , f0-(Q-1)f p , …, f0+(Q-1)f p , f0+Qf p , and synthesize an intermediate frequency signal containing 2Q+1 harmonics.

[0098] Step A3: The transceiver isolation switch 2 selects the receiving link, and the synthesized single digital intermediate frequency signal is up-converted to radio frequency through the receiving link and radiated to space through the horn antenna 1 and the super surface 7, where the signal at the center frequency f c contains user precoding information and is considered as useful signal, and let the kth user use a single antenna to receive the signal, then the useful signal received at the kth user is represented as

[0099]

[0100] Where is the Fourier coefficient of the qth harmonic of the nth super surface 7 unit transmission mode, which is given by

[0101]

[0102] Where is the equivalent periodic modulation function of the nth super surface 7 unit periodically amplitude and phase modulated in the transmission mode.

[0103] For the transmitting mode, set an 18x18 unit of the metasurface 7 also works at 5.8GHz, divided into 9 sub-arrays, the metasurface 7 unit periodically adjusts the radio frequency space feed signal from the horn antenna 1 in the transmitting mode, the adjustment method is to periodically switch the phase of the space feed signal between 0° and 180°, and the equivalent modulation function is given by the following formula

[0104]

[0105] Set the MIMO transceiver based on the metasurface 7 to serve 4 single antenna users, the baseband signal transmission to each user is modulated by 16QAM, and the frequency of the periodic adjustment at the radio frequency end is 20MHz. First, the signals of the 4 users are pre-encoded according to the harmonic signals of the estimated channel in the receiving mode, and 9 pre-encoded signal outputs are obtained, then 9 digital mixers 10 are used to digitally quadrature up-convert the 9 outputs to intermediate frequencies with a spacing of 20MHz, and through the receiving link up-convert to radio frequencies with a spacing of 5.72GHz-5.88GHz, and finally incident on the metasurface 7 unit by the horn antenna 1. The pre-encoding between each user signal and each harmonic can use the minimum mean square error criterion (MMSE), and the final radio frequency signal incident on the horn antenna 1 is shown in Figure 4 , containing 9 harmonic components after harmonic pre-encoding and up-conversion. The metasurface 7 unit periodically adjusts the space feed signal under the control of the periodic adjustment timing and radiates it into space.

[0106] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essential content of the present application. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A metasurface-based MIMO transceiver system, characterized by, The application relates to a horn antenna (1), a transceiver isolation switch (2), a receiving link, a transmitting link, a middle-frequency digital signal processing module (14), a digital controller (13) and a super surface (7); the horn antenna (1) is connected with the transceiver isolation switch (2), the transceiver isolation switch (2) is connected with the receiving link and the transmitting link, the receiving link and the transmitting link are connected with the middle-frequency digital signal processing module (14), and the digital controller (13) is connected with the middle-frequency digital signal processing module (14) and the super surface (7). The super surface (7) comprises N periodically arranged electromagnetic regulation micro units, the electromagnetic regulation micro units are of a reflective type, a transmissive type or a reflective / transmissive adjustable type structure. The digital controller (13) generates corresponding periodic digital control signals according to a periodic modulation time sequence, and controls the middle-frequency digital signal processing module (14) to complete a receiving and transmitting signal processing procedure. The electromagnetic regulation micro units periodically adjust phases or amplitudes of reflected electromagnetic waves or transmitted electromagnetic waves under the action of control signals of the digital controller (13). The transceiver isolation switch (2) selects the receiving link and the transmitting link in time, and corresponds to two working modes of a receiving mode and a transmitting mode. The receiving mode comprises the following steps. Step S1: The transceiver isolation switch (2) selects the receiving link, periodically amplitude-phase modulates a space incoming wave signal through the super surface (7), receives the space incoming wave signal through the horn antenna (1), and transmits the space incoming wave signal to the middle-frequency digital signal processing module (14) through a receiving link frequency down conversion and middle-frequency sampling. Qf Step S2: the single channel intermediate frequency digital signal received by the intermediate frequency digital signal processing module (14) contains periodic modulation introduced infinite harmonic signals, using 2Q+1 digital mixers (10) to digitally quadrature down-convert the harmonic signals with center frequencies of f 0- Qf p 、 f 0-( Q -1) f p 、…、 f 0+( Q -1) f p 、 f 0+ qf p to baseband; assuming that the received signal contains k single transmitting antenna user signals, then at the baseband, the model of the q th harmonic signal is: where K is the number of served users, satisfying K≤N≤2Q+1, E k and s k are the transmit power and the transmit baseband symbol signal of the k th user, respectively, h n,k is the channel response between the n th metasurface (7) element and the k th user, p n,q is the fixed near-field channel response of the horn antenna (1) to the n th metasurface (7) element at the q th harmonic frequency f c + The receiving link comprises sequentially connected low-noise amplifiers (3), mixers (6) and analog-to-digital converters (8), and a radio frequency local oscillator (5) connected with the mixers (6); the receiving link amplifies a receiving signal strength from the horn antenna (1), converts a radio frequency signal to a middle frequency, and converts the middle frequency signal into a digital signal. p obtained from calibration measurements, where f c is the incoming radio frequency center frequency, is the Fourier coefficient of the n th harmonic of the receive pattern of the q th metasurface (7) element, given by wherein is the equivalent periodic modulation function of the nth metasurface (7) unit in receive mode periodic amplitude-phase modulation; n is the equivalent periodic modulation function of the nth metasurface (7) unit in receive mode periodic amplitude-phase modulation; Step S3: The harmonic processing module (12) jointly down-converts the 2Q+1 baseband harmonic signals based on the harmonic signal model, performs channel estimation based on the baseband harmonic signals, and detects and demodulates the output multi-user signals from the baseband harmonic signals, and sets the estimated channel response as , the MIMO detection vector of the first k user is then the signal output by the first k user is detected as 。 2. The metasurface-based MIMO transceiver system of claim 1, wherein: The transmitting link comprises sequentially connected digital-to-analog converters (9), mixers (6) and power amplifiers (4), and a radio frequency local oscillator (5) connected with the mixers (6); the transmitting link converts a digital signal into an analog signal, converts a middle frequency signal to a radio frequency, and radiates the radio frequency signal out through the horn antenna (1) after power amplification.

3. The metasurface-based MIMO transceiver system of claim 1, wherein: The middle-frequency digital signal processing module (14) comprises a middle-frequency digital local oscillator (11), a digital mixer (10) and a harmonic processing module (12); the middle-frequency digital signal processing module (14) realizes mapping between multi-user signals and 2Q+1 harmonics through orthogonal digital down conversion, orthogonal digital up conversion and the harmonic processing module (12).

4. The metasurface-based MIMO transceiver system of claim 1, wherein: Qf The digital mixer (10) is provided with 2Q+1, the center frequency is respectively f 0- Qf p 、 f 0-( Q -1) f p 、…、 f 0+( Q -1) f p 、 f 0+ The harmonic processing module (12) performs channel estimation and MIMO detection on 2Q+1 baseband harmonic signals in the receiving mode, and demodulates and outputs information transmitted by users; p Wherein f 0 is the center frequency of analog down conversion, f p is the frequency of the periodic amplitude and phase adjustment of the super surface (7); the digital mixer (10) is respectively orthogonal digital down conversion to the baseband in the receiving mode, and is respectively up-converted to the corresponding harmonic intermediate frequency in the transmitting mode. In the transmitting mode, multi-user baseband modulation signals are mapped into 2Q+1 harmonic baseband signals through precoding. The transmitting mode comprises the following steps:

5. The metasurface-based MIMO transceiver system of claim 1, wherein: Qf Step A1: The harmonic processing module (12) uses the channel response estimated by the receiving mode to map the baseband signals of K users into 2Q+1 signals through harmonic-based precoding, where K≤N≤2Q+1, corresponding to the 2Q+1th baseband harmonic signals respectively. k The beamforming vectors precoded by each user are: The post-harmonic precoding signal is represented as: q Q q Q The post-harmonic precoding signal is represented as:​​​ wherein s k a baseband signal for transmission to the first k user; Step A2: in the intermediate frequency digital signal processing module (14), using 2Q+1 digital frequency converters (10) to respectively digitally quadrature up-convert the 2Q+1 harmonic pre-coded signals to f 0- Qf p 、 f 0- Q -1) f p 、 f 0+ Q -1) f p 、 f 0+ ​ p at the frequency, and synthesize an intermediate frequency signal containing 2Q+1 harmonics; Step A3: the transceiving isolator (2) selects the receiving link, the synthesized single-path digital intermediate frequency signal is up-converted to radio frequency through the receiving link, and is incident to the metasurface (7) through the horn antenna (1), and is radiated to the space after being periodically amplitude and phase modulated by the metasurface (7), wherein the signal at the center frequency f c contains user precoding information and is regarded as a useful signal, and the useful signal received at the i-th user is represented as k k ​​ wherein is the Fourier coefficient of the nth harmonic of the emission pattern of the mth metasurface (7) unit n is the Fourier coefficient of the nth harmonic of the emission pattern of the mth metasurface (7) unit q is the Fourier coefficient of the nth harmonic of the emission pattern of the mth metasurface (7) unit wherein is the equivalent periodic modulation function of the nth metasurface (7) unit in the transmit mode. n is the equivalent periodic modulation function of the nth metasurface (7) unit in the transmit mode.

6. The metasurface-based MIMO transceiver system of claim 1 or 5, wherein: The equivalent periodic modulation function selection standard of the metasurface (7) unit in the transmitting mode or the receiving mode is that: 2Q+1 harmonic signals selected before or after modulation from-Q to Q are independent of each other, and the frequency of the periodic amplitude and phase modulation is less than the maximum bandwidth B of the transceiving baseband signal max satisfies the following formula: 。 7. The metasurface-based MIMO transceiver system of claim 1 or 5, wherein: at the center frequency and the periodic amplitude and phase modulation frequency of the metasurface (7) f p After the determination, the selected Qth to Qth harmonic signals can be replaced by harmonic signals of any 2Q+1 different harmonic frequencies, the selected 2Q+1 harmonic signals are independent of each other, and Q satisfies 2Q+1≥N≥K.

8. The metasurface-based MIMO transceiver system of claim 1 or 5, wherein: The super surface (7) is divided into N0 sub-arrays by N periodically arranged electromagnetic regulation micro cells to realize MIMO transceiving function, and the selection of the number of harmonics, the number of sub-arrays and the number of users to be served is limited by K≤N0≤2Q+1.

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