CN117792457B - Intelligent reflection surface adjustable reflection gain method based on hybrid unit subarray - Google Patents

Abstract

The invention discloses an intelligent reflection surface adjustable reflection gain method based on a hybrid unit subarray, which relates to the technical field of electronic information, wherein the intelligent reflection surface comprises a dual-polarized intelligent reflection surface formed by a passive reflection unit and an active reflection unit; the method comprises the following steps: s1: the intelligent reflecting surface of the mixing unit receives signals sent by the transmitting end; s2: judging according to the intensity and the distance of the signal required by the receiving end, and adaptively starting the number of active reflection units required by the corresponding intensity or distance; s3: acquiring signal power received when the active reflecting unit is not started by the mixed intelligent reflecting surface; s4: according to the received signal power, the subunit array makes a judgment that the main ratio of the active reflecting unit to the passive reflecting unit is 1:8,2:7 and 3: 6. The method solves the problem of multiplicative fading of the reflected signal caused by double-path loss of the reflected signal of the traditional intelligent reflecting surface.

Description

A method for adjustable reflection gain of smart reflective surface based on hybrid unit subarray

Technical Field

The invention relates to the field of electronic information technology, and in particular to an adjustable reflection gain method of an intelligent reflection surface based on a hybrid unit subarray.

Background technique

With the rapid development of the information age, mobile communication networks have gradually moved from the 5G era to the research of 6G technology. The white paper "6G Overall Vision and Potential Key Technologies" released by the China Academy of Communications Technology Promotion Group clearly points out that smart reflective surfaces have become one of the important technologies for realizing 6G networks. Many scholars at home and abroad have invested in the exploration of smart reflective surfaces, and have shown from both theoretical and practical perspectives that smart reflective surfaces will occupy a very important position in the future realization of 6G technology. In the current research on smart reflective surfaces, in the research on passive reflective units as the main component units, it has been found that if the reflective surface is composed only of passive reflective units, it will cause the phenomenon of "multiplicative fading" of the reflected signal.

The multiplicative fading effect originates from two paths: the base station (BS) to the intelligent reflection surface (RIS) and the intelligent reflection surface to the user equipment (UE), and the product of the lengths of these two paths is proportional to the attenuation. Therefore, the intelligent reflection surface composed only of passive reflection units is difficult to meet the requirements of increasing and increasing the coverage of the reflected signal. Based on this, active reflection units have become a current research hotspot because they can effectively increase the strength of the reflected signal. However, there is no good unified standard for the use and deployment of active reflection units. Most of them are randomly distributed or cannot be turned on and off according to the signal strength.

Summary of the invention

The purpose of the present invention is to provide a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray, which solves the problem of multiplicative fading of reflected signals caused by a reflection surface currently composed of a single passive reflection unit and the problem of how to allocate active reflection units and passive reflection units. At the same time, this dynamic switching method can solve the problem of complex control circuits and hardware costs caused by replacing all units with active units.

To achieve the above object, the present invention provides a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray, wherein the intelligent reflection surface comprises a dual-polarization intelligent reflection surface composed of a passive reflection unit and an active reflection unit; the method specifically comprises the following steps:

S1: The hybrid unit intelligent reflection surface receives the signal sent by the transmitter. The signal of the transmitter comes from the base station. The user is the final receiving end. The user moves randomly and receives signals transmitted or reflected by different base stations or hybrid unit intelligent reflection surfaces.

S2: According to the strength and distance of the signal required by the receiving end, the number of active reflector units required for the corresponding strength or distance is adaptively turned on;

S3: obtaining the signal power received by the hybrid unit intelligent reflection surface when the active reflection unit is not turned on;

S4: According to the received signal power, the sub-unit array makes a judgment and turns on or off a certain number of active reflector units. The main ratio of active reflector units to passive reflector units is 1:8, 2:7 and 3:6.

Preferably, the size of each reflection unit is 2cm×2cm, and nine reflection units form a 3×3 reflection surface subarray. The active reflection units are arranged to be distributed in an x-axis or y-axis symmetrical form, and the remaining four positions are passive reflection units. The subunit is composed of a maximum of 5 active reflection units and 4 passive reflection units.

Preferably, in step S2, the reflection coefficient is assumed to be Γ, and the formula of the reflection coefficient is as follows:

Where Z _L and Z _A represent the load and antenna impedance respectively;

The passive intelligent reflector uses a passive load, and the corresponding reflection coefficient |Γ| ² ≤1. It is concluded that the reflection coefficient of the passive reflector is less than 1, resulting in path loss.

A tunnel diode is added to the passive reflection unit. According to the negative input resistance characteristic of the tunnel diode, the reflection coefficient |Γ| ² ≥ 1. The specific formula of the tunnel diode impedance is as follows:

Z _L = -R _L + jX _L , R _L > 1

Where R _L and _XL represent resistance and reactance respectively. According to the above formula, the formula of the reflection coefficient of the active reflection unit is specifically expressed as:

Wherein _RA and _XA represent resistance and reactance respectively. According to the above formula, when the signal strength needs to be increased, the reflection coefficient |Γ| ² ≥ 1 is set, the active reflection unit is turned on, and the proportion of the active reflection unit turned on is obtained according to the strength required by the user;

The distance from the base station to the center of the hybrid unit intelligent reflection surface is set to d ₁ , and the distance from the center of the hybrid unit intelligent reflection surface to the user is set to d ₂ . According to the formula of path loss, the corresponding path loss is obtained. The specific expression is:

Where _Gt represents the gain of the transmitting antenna, _Gr represents the gain of the receiving antenna, Γ represents the reflection gain of a single unit, M represents the number of columns of the unit, N represents the number of rows of the reflector unit, _dx represents the width of a unit, _dy represents the length of a unit, A represents the amplitude, λ represents the wavelength, and F(θ, φ) is the normalized power radiation pattern of the unit, which reveals the dependence of the incident/reflected power density of the unit on the incident/reflection angle, where θ represents the elevation angle, φ represents the azimuth angle, and the specific expression of F(θ, φ) is as follows:

The corresponding path loss is calculated from the above two formulas of PL and F(θ, φ), and it is concluded that when the signal is reflected only by the passive intelligent reflective surface, the path loss will increase exponentially.

Preferably, in step S3, the signal is transmitted from the base station to the hybrid unit intelligent reflection surface. The hybrid unit intelligent reflection surface calculates the signal power received when the user does not turn on the active reflection unit according to the distance from the reflection surface to the user. Assuming the power of the base station transmission signal is P _t , and the variables involved in step S2, the signal power P _r received when the user does not turn on the active reflection unit is calculated. The specific formula is expressed as follows:

According to the above formula, the signal power received when the user does not turn on the active reflection unit is calculated.

Preferably, in step S4, the hybrid unit intelligent reflection surface is composed of active reflection units and passive reflection units, the unit geometry is symmetrical about the X-axis and the Y-axis, the unit period and size are designed according to the specified working center frequency, each 3×3 is a subarray, and in a single subarray, the active reflection units are deployed in a "symmetrical" form. When the hybrid unit intelligent reflection surface obtains the result of step S3, the subunit array makes a judgment to turn on or off a certain number of active reflection units, and the main ratio of the active reflection unit to the passive reflection unit will become 1:8, 2:7 and 3:6.

Therefore, the present invention adopts the above-mentioned intelligent reflective surface adjustable reflection gain method based on hybrid unit subarray, which has the following beneficial effects:

(1) The present invention solves the problem of "multiplicative fading" of the reflected signal of the traditional intelligent reflector caused by the dual path loss, and can selectively control the combination of active units and passive units.

(2) The present invention realizes a communication scenario of purposefully amplifying the target signal by adjusting the ratio of the active reflection unit and the passive reflection unit.

(3) The present invention pre-designs the active units so that only three out of every nine units are set as active units, which has the advantages of reducing the cost of semiconductor materials and the complexity of the control circuit.

(4) The present invention verifies that the hybrid reflective surface can effectively enhance the reflected signal and expand the signal transmission range, thereby reducing the deployment of base stations and effectively saving resources.

The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a method flow chart of a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray according to the present invention;

2 is a deployment diagram of a passive reflection unit and an active reflection unit of a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray according to the present invention;

3 is a position relationship diagram of a base station to a smart reflective surface and a smart reflective surface to a user in a method for adjustable reflection gain of a smart reflective surface based on a hybrid unit subarray of the present invention;

4 is a diagram showing the relationship between the ratio of passive reflective units to active reflective units and the reflective surface gain in a method for adjustable reflective gain of an intelligent reflective surface based on a hybrid unit subarray according to the present invention;

5 is a graph showing the relationship between the reflector gain and the transmission distance d2 in a method for adjustable reflector gain of an intelligent reflector based on a hybrid unit subarray according to the present invention;

FIG6 is a deployment diagram of an 18×18 hybrid reflective unit array of a method for adjustable reflective gain of a smart reflective surface based on a hybrid unit subarray according to the present invention;

FIG. 7 is a diagram of a passive reflection unit and an active reflection unit in a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray according to the present invention.

Detailed ways

The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

Example

As shown in FIG. 1 to FIG. 6 , the present invention provides a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray. The method is applicable to an intelligent reflection surface, wherein the intelligent reflection surface includes a dual-polarization intelligent reflection surface composed of a passive reflection unit and an active reflection unit. The method specifically includes the following steps:

S1: The hybrid unit intelligent reflection surface receives the signal sent by the transmitter. The transmitter signal comes from the base station. The user is the final receiving end. The user moves randomly and receives signals transmitted or reflected by different base stations or hybrid unit intelligent reflection surfaces. The diagram of the passive reflection unit and the active reflection unit is shown in Figure 7.

As shown in Figure 2, the intelligent reflection surface of this example is composed of passive reflection units and active reflection units. The unit geometry is symmetrical about the X-axis and the Y-axis. The unit period and size are designed according to the required working center frequency. The deployment of 3×3 reflection units is used as a subarray. The active reflection units in each subarray are deployed in a symmetrical form, that is, in a subarray, the deployment positions of the active units are the upper left, upper right, center, lower left and lower right. Each active reflection unit can be controlled independently. In actual applications, the base station is the transmitting end and the user is the receiving end. The hybrid reflection surface can effectively enhance the reflected signal and expand the signal transmission range, thereby reducing the deployment of base stations and effectively saving resources.

S2: According to the strength and distance of the signal required by the receiving end, the number of active reflective units required for the corresponding strength or distance is adaptively turned on to amplify the incident signal.

When the center frequency is 3.5GHz, the size of each reflection unit is 2cm×2cm, and nine reflection units form a 3×3 reflection surface subarray. The active reflection units are set to be distributed in an x-axis or y-axis symmetrical form, and the remaining four positions are passive reflection units. The subunits are composed of a maximum of 5 active reflection units and 4 passive reflection units. Due to hardware cost and circuit complexity, it is not recommended to use a reflection surface subarray with more than 5 active reflection units.

Specifically, in this example, when the hybrid unit intelligent reflection surface receives a signal from the base station, the distance of the target user to be transmitted is judged to activate a mobile number of active reflection units to achieve the purpose of enhancing the signal strength. In step S2, the reflection coefficient is set to Γ, and the formula of the reflection coefficient is as follows:

Where Z _L and Z _A represent the load and antenna impedance respectively;

The passive intelligent reflector uses a passive load, and the corresponding reflection coefficient |Γ| ² ≤1. It is concluded that the reflection coefficient of the passive reflector is less than 1, resulting in path loss;

A tunnel diode is added to the passive reflection unit. According to the negative input resistance characteristic of the tunnel diode, the reflection coefficient |Γ| ² ≥ 1. The specific formula of the tunnel diode impedance is as follows:

Z _L = -R _L + jX _L , R _L > 1

Where R _L and _XL represent resistance and reactance respectively. According to the above formula, the formula of the reflection coefficient of the active reflection unit is specifically expressed as:

Wherein _RA and _XA represent resistance and reactance respectively. According to the above formula, when the signal strength needs to be increased, the reflection coefficient |Γ| ² ≥ 1 is set, the active reflection unit is turned on, and the proportion of the active reflection unit turned on is obtained according to the strength required by the user;

As shown in FIG3 , the distance from the base station to the center of the hybrid unit intelligent reflection surface is set to d ₁ , and the distance from the center of the hybrid unit intelligent reflection surface to the user is set to d ₂ . According to the formula of path loss, the corresponding path loss is obtained. The specific expression is:

Where _Gt represents the gain of the transmitting antenna, _Gr represents the gain of the receiving antenna, Γ represents the reflection gain of a single unit, M represents the number of columns of the unit, N represents the number of rows of the reflector unit, _dx represents the width of a unit, _dy represents the length of a unit, A represents the amplitude, λ represents the wavelength, and F(θ, φ) is the normalized power radiation pattern of the unit, which reveals the dependence of the incident/reflected power density of the unit on the incident/reflection angle, where θ represents the elevation angle, φ represents the azimuth angle, and the specific expression of F(θ, φ) is as follows:

The corresponding path loss is calculated from the above two formulas of PL and F(θ, φ), and it is concluded that when the signal is reflected only by the passive intelligent reflective surface, the path loss will increase exponentially.

S3: Obtain the signal power received by the hybrid unit intelligent reflection surface when the active reflection unit is not turned on; Specifically, in step S3, the signal is transmitted from the base station to the hybrid unit intelligent reflection surface, and the hybrid unit intelligent reflection surface will calculate the signal power received by the user when the active reflection unit is not turned on according to the distance transmitted from the reflection surface to the user. Assume that the power of the base station transmission signal is P _t , and the variables involved in step S2, calculate the signal power P _r received by the user when the active reflection unit is not turned on. The specific formula is expressed as follows:

According to the above formula, the signal power received when the user does not turn on the active reflection unit is calculated.

S4: According to the received signal power, the sub-unit array makes a judgment to turn on or off a certain number of active reflector units. The ratio of active reflector units to passive reflector units (hereinafter referred to as "main-to-passive ratio") is 1:8, 2:7 and 3:6. Specifically, as shown in Figure 2, in step S4, the hybrid unit intelligent reflection surface is composed of active reflection units and passive reflection units, the unit geometry is symmetrical about the X-axis and the Y-axis, the unit period and size are designed according to the specified working center frequency, each 3×3 is a subarray, and in a single subarray, the active reflection units are deployed in a "symmetrical" form. When the hybrid unit intelligent reflection surface obtains the result of step S3, the subunit array makes a judgment to turn on or off a certain number of active reflection units, and the main ratio of active reflection units to passive reflection units will become 1:8, 2:7 and 3:6. Of course, according to the compromise between the needs of actual applications and the cost of the reflection surface, the active reflection units can be appropriately increased, such as 4:5 and 5:4.

Therefore, the present invention adopts the above-mentioned method of adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray, which solves the "multiplicative fading" problem caused by the current single reflection surface composed of passive reflection units and the problem of how to allocate active reflection units and passive reflection units. By regulating the ratio of active reflection units and passive reflection units, a communication scenario of purposefully amplifying target signals is realized. The hybrid reflection surface can effectively enhance the reflected signal and expand the signal transmission range, thereby reducing the deployment of base stations and effectively saving resources.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims (2)

1. A method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray, characterized in that: the intelligent reflection surface includes a dual-polarization intelligent reflection surface composed of a passive reflection unit and an active reflection unit; nine reflection units form a 3×3 reflection surface subarray, the active reflection unit is arranged to be distributed in an x-axis or y-axis symmetrical form, the subunit is at least composed of 1 placed in the center or 2 active reflection units, and the remaining positions are composed of passive reflection units; the subunit is composed of 3 active reflection units and 6 passive reflection units at most; The method specifically comprises the following steps: S1: The hybrid unit intelligent reflection surface receives the signal sent by the transmitter. The signal of the transmitter comes from the base station. The user is the final receiving end. The user moves randomly and receives signals transmitted or reflected by different base stations or hybrid unit intelligent reflection surfaces. S2: According to the strength and distance of the signal required by the receiving end, the number of active reflection units required for the corresponding strength or distance is adaptively turned on; in step S2, the reflection coefficient is set to Γ, and the formula of the reflection coefficient is as follows: Where Z _L and Z _A represent the load and antenna impedance respectively; The passive intelligent reflector uses a passive load, and the corresponding reflection coefficient |Γ| ² ≤1. It is concluded that the reflection coefficient of the passive reflector is less than 1, resulting in path loss; A tunnel diode is added to the passive reflection unit. According to the negative input resistance characteristic of the tunnel diode, the reflection coefficient |Γ| ² ≥ 1. The specific formula of the tunnel diode impedance is as follows: Z _L = -R _L + jX _L , R _L > 1 Where R _L and _XL represent resistance and reactance respectively. According to the above formula, the formula of the reflection coefficient of the active reflection unit is specifically expressed as: Wherein _RA and _XA represent resistance and reactance respectively. According to the above formula, when the signal strength needs to be increased, the reflection coefficient |Γ| ² ≥ 1 is set, the active reflection unit is turned on, and the proportion of the active reflection unit turned on is obtained according to the strength required by the user; The distance from the base station to the center of the hybrid unit intelligent reflection surface is set to d ₁ , and the distance from the center of the hybrid unit intelligent reflection surface to the user is set to d ₂ . According to the formula of path loss, the corresponding path loss is obtained. The specific expression is: Where _Gt represents the gain of the transmitting antenna, _Gr represents the gain of the receiving antenna, Γ represents the reflection gain of a single unit, M represents the number of columns of the unit, N represents the number of rows of the reflector unit, _dx represents the width of a unit, _dy represents the length of a unit, A represents the amplitude, λ represents the wavelength, and F(θ, φ) is the normalized power radiation pattern of the unit, which reveals the dependence of the incident/reflected power density of the unit on the incident/reflection angle, where θ represents the elevation angle, φ represents the azimuth angle, and the specific expression of F(θ, φ) is as follows: The corresponding path loss is calculated from the above two formulas of PL and F(θ, φ), and it is concluded that when the signal is reflected only by the passive intelligent reflector, the path loss will increase exponentially; S3: obtaining the signal power received by the hybrid unit intelligent reflection surface when the active reflection unit is not turned on; In step S3, the signal is transmitted from the base station to the hybrid unit intelligent reflective surface. The hybrid unit intelligent reflective surface calculates the signal power received when the user does not turn on the active reflective unit according to the distance from the reflective surface to the user. Assuming the power of the base station transmission signal is P _t , and the variables involved in step S2, the signal power P _r received when the user does not turn on the active reflective unit is calculated. The specific formula is expressed as: According to the above formula, the signal power received when the user does not turn on the active reflector unit is calculated; S4: According to the received signal power, the sub-unit array makes a judgment and turns on or off a certain number of active reflection units. The main ratio of active reflection units to passive reflection units is 1:8, 2:7 and 3:6. 2. According to claim 1, a method for adjustable reflection gain of an intelligent reflection surface based on a hybrid unit subarray is characterized in that: in step S4, the hybrid unit intelligent reflection surface is composed of an active reflection unit and a passive reflection unit, the unit geometric structure is symmetrical about the X-axis and the Y-axis, the unit period and size are designed according to the specified working center frequency, each 3×3 is a subarray, and in a single subarray, the active reflection unit is deployed in a "symmetrical" form. When the hybrid unit intelligent reflection surface obtains the result of step S3, the subunit array makes a judgment to turn on or off a certain number of active reflection units.