KR102195232B1 - Wireless power transfer system and method of beamforming weight estimating - Google Patents

Abstract

Disclosed are a wireless power transmission system and a beam forming weight estimating method thereof which can solve feedback overhead problem. The beam forming weight estimating method in the wireless power transmission system comprises the steps of: allowing a transmitter to transmit a beam steering pilot signal to a receiver in the order of a beam forming codebook; allowing the receiver to select a section of a beam space corresponding to a transmission path of an energy signal transmitted from the transmitter in accordance with average power of the beam steering pilot signal measured for each section of the entire beam space to feed back an index to the transmitter; and allowing the transmitter to calculate a beam forming weight of a phase array antenna by finding the section of the beam space corresponding to the index feedback of the receiver in the beam forming codebook.

Description

Wireless power transmission system and its beamforming weight estimation method {WIRELESS POWER TRANSFER SYSTEM AND METHOD OF BEAMFORMING WEIGHT ESTIMATING}

The present invention relates to a wireless power transmission system and a method for estimating a beamforming weight thereof, and more particularly, a wireless power transmission system for transmitting a beamformed energy signal from a transmitter composed of a phased array antenna to a receiver, and a beamforming weight estimation thereof. It's about how.

Wireless power transmission system refers to a technology that transmits power through radio waves without wires.

One of the methods for determining the optimal propagation path in a radio frequency (RF) wireless power transmission system using a phased array antenna is a method of consistently matching the phase of a signal transmitted for each phased array antenna by estimating a beamforming weight. There is this.

For beamforming weight estimation, a transmitter periodically transmits a pilot signal to a receiver, and the receiver may estimate a channel coefficient for each antenna, that is, a beamforming weight for each antenna, using the pilot signal. In addition, the receiver may feed back the beamforming weight for each antenna to the transmitter through a communication channel. The transmitter may transmit the beamformed energy signal in an optimal direction using the feedback information.

However, since the number of channel coefficients to be fed back increases in proportion to the number of antennas, such a conventional method has a problem in that the feedback overhead of a communication channel required for a wireless power transmission process increases as the number of antennas increases.

An aspect of the present invention provides a wireless power transmission system for estimating a beamforming weight based on beam scanning through a beam steering pilot, and a method for estimating a beamforming weight thereof.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

The method for estimating a beamforming weight in a wireless power transmission system of the present invention for solving the above problem is a method for estimating a beamforming weight in a wireless power transmission system in which a beamformed energy signal is transmitted from a transmitter composed of a phased array antenna to a receiver. Wherein the transmitter transmits a beam steering pilot signal in the order of a beamforming codebook in which an index is assigned by dividing a section of the entire beam space to the receiver, and the beam steering pilot signal measured for each section of the entire beam space by the receiver Selecting a section of the beam space corresponding to the transmission path of the energy signal transmitted from the transmitter according to the average power of the transmitter, the receiver determines the index assigned to the section of the beam space corresponding to the transmission path of the energy signal And calculating, by the transmitter, a beamforming weight of the phased array antenna by finding a section of a beam space corresponding to the index feedback of the receiver in the beamforming codebook.

Meanwhile, the step of selecting, by the receiver, a section of the beam space corresponding to the transmission path of the energy signal transmitted from the transmitter according to the average power of the beam steering pilot signal measured for each section of the entire beam space. It may be a step of selecting a section of the section in which the average power of the beam steering pilot signal is the maximum as a section of the beam space corresponding to the transmission path of the energy signal.

In addition, the transmitting of the beam steering pilot signal in the order of the beamforming codebook in which the index is assigned by dividing the section of the entire beam space to the receiver by the transmitter includes an azimuth angle and an upper and lower angle representing each section of the entire beam space. It may include the step of designing the beamforming codebook by giving an index to the (elevation angle).

In addition, the transmitting of the beam steering pilot signal in the order of the beamforming codebook in which the index is assigned by dividing the section of the entire beam space to the receiver by the transmitter may include a wireless power transmission frame in the receiver before transmitting the beam steering pilot signal. It may include transmitting a synchronization signal to the receiver to detect the start timing.

In addition, the step of the receiver feeding back the index assigned to the section of the beam space corresponding to the transmission path of the energy signal to the transmitter, a beamforming code by applying a gray code for each index of the beamforming codebook. Designing a word, and selecting a codeword corresponding to an index assigned to a section of a beam space corresponding to a transmission path of the energy signal from the beamforming codeword and feeding back to the transmitter.

Further, the step of calculating, by the transmitter, a beamforming weight of the phased array antenna by finding a section of a beam space corresponding to the index feedback of the receiver in the beamforming codebook, corresponds to the index feedback of the receiver in the beamforming codebook. And extracting an azimuth angle and an upper and lower angle representing a section of the beam space to be defined, and calculating a beamforming weight for each phased array antenna using the azimuth angle, the upper and lower angle, and a distance between the phased array antenna.

Meanwhile, the wireless power transmission system of the present invention is a wireless power transmission system that transmits a beamformed energy signal from a transmitter composed of a phased array antenna to a receiver, the beamforming codebook obtained by dividing the entire beam space with the receiver and giving an index By transmitting a beam steering pilot signal in the order of, receiving an index feedback selected according to the average power of the beam steering pilot signal, and finding a section of the beam space corresponding to the index feedback of the receiver in the beamforming codebook Select a section of the beam space corresponding to the transmission path of the energy signal transmitted from the transmitter according to the average power of the beam steering pilot signal measured for each section of the transmitter and the entire beam space for calculating the beamforming weight of the array antenna, And a receiver for feeding back an index assigned to a section of a beam space corresponding to a transmission path of the energy signal to the transmitter.

Meanwhile, the transmitter may transmit a synchronization signal to the receiver so that the receiver may detect a start timing of a wireless power transmission frame before transmitting the beam steering pilot signal.

According to the present invention, it is possible to solve a problem of feedback overhead that increases according to the number of antennas by estimating a beamforming weight based on beam scanning through a beam steering pilot.

In addition, since the optimal energy signal transmission path can be identified through simple power detection in the receiver, the complexity of the receiver can be minimized.

1 is a schematic diagram of a wireless power transmission system according to an embodiment of the present invention.
2 is a diagram illustrating energy signal transmission in a wireless power transmission system according to an embodiment of the present invention shown in FIG. 1.
FIG. 3 is a diagram schematically illustrating a structure of a wireless power transmission frame of the wireless power transmission system according to an embodiment of the present invention shown in FIG. 1.
4 is a control block diagram of the transmitter shown in FIG. 1.
5 is a control block diagram of the receiver shown in FIG. 1.
6 is a diagram for explaining index feedback in the receiver illustrated in FIG. 5.
7 is a flowchart illustrating a method of estimating a beamforming weight in a wireless power transmission system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The detailed description of the present invention to be described below refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in detail sufficient to enable a person skilled in the art to practice the present invention. It is to be understood that the various embodiments of the present invention are different from each other but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention in relation to one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the detailed description to be described below is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all scopes equivalent to those claimed by the claims. In the drawings, like reference numerals refer to the same or similar functions over several aspects.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

1 is a schematic diagram of a wireless power transmission system according to an embodiment of the present invention.

Referring to FIG. 1, a wireless power transmission system 1 according to an embodiment of the present invention includes a transmitter 100 and a receiver 200, and can transmit an energy signal from the transmitter 100 to the receiver 200. have.

For example, the wireless power transmission system 1 according to an embodiment of the present invention may be a system that transmits power through a radio frequency (RF) signal.

In the wireless power transmission system 1 according to an embodiment of the present invention, the transmitter 100 may be configured as a phased array antenna to transmit a beamformed energy signal from the transmitter 100 to the receiver 200. This will be described with reference to FIG. 2.

2 is a diagram illustrating energy signal transmission in a wireless power transmission system according to an embodiment of the present invention shown in FIG. 1.

Referring to FIG. 2, the transmitter 100 may include a plurality of antennas 10 in a linear arrangement.

For example, the transmitter 100 may include a planar phased array antenna 10 in which a plurality of antennas 10 are linearly arranged in the x-axis direction and the y-axis direction, respectively.

The transmitter 100 may transmit the beamformed energy signal to the receiver 200 through the 3D beam space by the planar phased array antenna 10.

Meanwhile, in a wireless power transmission system having a planar phased array antenna, it is necessary to match the phases of signals transmitted for each antenna to an optimal energy signal transmission path. The beamforming weight is used to consistently match the phase of signals transmitted by each antenna. In general, the transmitter 100 can receive a feedback of the beamforming weight for each antenna from the receiver 200, and when transmitting wireless power The beamforming weight is multiplied for each antenna.

Briefly describing the conventional beamforming weight feedback method, the transmitter 100 periodically transmits a pilot signal to the receiver 200, and the receiver 200 estimates a channel coefficient for each antenna using a pilot signal, It feeds back to the transmitter 100. However, in such a method, since the number of channel coefficients to be fed back increases in proportion to the number of antennas, as the number of antennas increases, the feedback overhead of a communication channel required for a wireless power transmission process increases.

The wireless power transmission system 1 according to an embodiment of the present invention selects an optimal energy signal transmission path based on beam scanning through beam steering pilots in the receiver 200, and the transmitter 100 ), and the transmitter 100 may estimate a beamforming weight for each antenna 10 using the feedback information. This will be described with reference to FIG. 3.

FIG. 3 is a diagram schematically illustrating a structure of a wireless power transmission frame of the wireless power transmission system according to an embodiment of the present invention shown in FIG.

Referring to FIG. 3, the transmitter 100 may transmit a synchronization signal to the receiver 200. The receiver 200 may detect the start timing of the wireless power transmission frame from the synchronization signal.

The transmitter 100 may transmit a beam steering pilot signal to the receiver 200. The beam steering pilot signal may be sequentially transmitted according to a pre-designed beamforming codebook. The receiver 200 may select an optimal energy signal transmission path through the beam steering pilot signal and feed back the information to the transmitter 100.

The transmitter 100 may estimate a beamforming weight for each phased array antenna using feedback information from the receiver 200, and apply the beamforming weight to transmit the beamformed energy signal through an optimal energy signal transmission path.

As described above, the wireless power transmission system 1 according to an embodiment of the present invention may set an optimal energy signal transmission path, which is a basis for calculating a beamforming weight, through a beam steering pilot signal, and feed it back to the transmitter 100. . Accordingly, the transmitter 100 may calculate a beamforming weight and transmit the beamformed energy signal through an optimal energy signal transmission path.

Hereinafter, each configuration of the wireless power transmission system 1 according to an embodiment of the present invention shown in FIG. 1 will be described in detail.

4 is a control block diagram of the transmitter shown in FIG. 1.

Referring to FIG. 4, the transmitter 100 may include a signal transmission control unit 110, a beamforming weight calculation unit 130, and an array factor calculation unit 150.

The signal transmission controller 110 may control transmission of various signals from the phased array antenna according to the wireless power transmission frame structure shown in FIG. 3.

The signal transmission control unit 110 may control the phased array antenna to first transmit a synchronization signal to the receiver 200 when transmitting wireless power. As described above, the synchronization signal may be used for detecting the start timing of the wireless power transmission frame in the receiver 200.

The signal transmission control unit 110 may control the phased array antenna to transmit a beam steering pilot signal to the receiver 200. The beam steering pilot signal may be a signal transmitted at a preset interval T _{b in the} order of indexes of the beamforming codebook. The phased array antenna may have a directionality capable of steering a beam in a desired direction. The signal transmission control unit 110 may control the directionality of each of the phased array antennas so that a pilot signal is transmitted to a beam space according to a beamforming codebook.

Specifically, the signal transmission control unit 110 may design a beamforming codebook.

The signal transmission control unit 110 divides the section of the 3D beam space to be scanned and assigns indexes to the azimuth angle (φ) and the elevation angle (θ) representing each section to design a beamforming codebook. I can. Table 1 below is an example of a beamforming codebook.

및 상하각

이고, 전체 빔 공간은 256개의 구간으로 분할될 수 있다. For example, the signal transmission control unit 110 may design a beamforming codebook composed of a 4-bits azimuth angle and a 4-bits vertical angle. Here, the entire section of the three-dimensional beam space to be scanned is the azimuth angle

And upper and lower angles

, And the total beam space may be divided into 256 sections.

At this time, the phase difference (Δφ, Δθ) between the azimuth angle and the vertical angle between adjacent beam sections may be calculated as in Equation 1 below.

,

는 스캐닝 하고자 하는 상하각의 최소값, 최대값을 나타내고,

는 스캐닝 하고자 하는 방위각의 최소값, 최대값을 나타낸다.In Equation 1

,

Represents the minimum and maximum values of the upper and lower angles to be scanned,

Represents the minimum and maximum values of the azimuth to be scanned.

The signal transmission control unit 110 may control to transmit a beam steering pilot signal to the receiver 200 at every preset time T _b based on the designed beamforming codebook.

For example, the signal transmission control unit 110 may transmit the beam steering pilot signal every preset time (T _b ) in the order of the index (β) of the beamforming codebook. In the case of Table 1, the signal transmission control unit 110 may control the directionality of the phased array antenna to transmit a pilot signal in a beam space having an azimuth and an upper and lower angle corresponding to β ₁ . The signal transmission control unit 110 may transmit a pilot signal in a beam space having an azimuth angle and an upper and lower angle corresponding to β ₂₅₆ at a predetermined time (T _b ) interval in the same manner.

The signal transmission control unit 110 may control the energy signal beamformed from the phased array antenna to be transmitted to the receiver 200. The signal transmission control unit 110 may control an energy signal to be transmitted from the phased array antenna by reflecting the beamforming weight for each phased array antenna calculated by the beamforming weight calculator 130 to be described later.

For example, the signal transmission control unit 110 may match the phase of the energy signal transmitted for each phased array antenna by multiplying the energy signal transmitted for each phased array antenna by a beamforming weight for each phased array antenna.

The beamforming weight calculator 130 may receive feedback information on a beam space corresponding to a transmission path of an energy signal from the receiver 200 and calculate a beamforming weight for each phased array antenna.

The receiver 200 measures the average power of the beam steering pilot signals received in the order of the index β of the beamforming codebook, and calculates the index β of the beamforming codebook when the average power is the maximum. 130). In this case, the receiver 200 may feed back the index in the form of a beamforming codeword to which a gray code is applied for each index of the beamforming codebook in order to minimize power loss due to a bit error during feedback. In this regard, a detailed description will be provided later.

The beamforming weight calculator 130 may extract an index of a beamforming codebook corresponding to the index feedback of the receiver 200. That is, the beamforming weight calculation unit 130 may extract the index of the beamforming codebook corresponding to the beamforming codeword received from the receiver 200 by referring to the codeword table for each index of the beamforming codebook shown in Table 2 below. I can.

The beamforming weight calculator 130 may extract a section of the beam space corresponding to the index feedback of the receiver 200 from the beamforming codebook. That is, the beamforming weight calculator 130 may extract an azimuth angle and an upper and lower angle of a beam space section corresponding to the index feedback of the receiver 200 from the beamforming codebook.

The beamforming weight calculator 130 may calculate a beamforming weight for each phased array antenna by using an azimuth and an upper and lower angle of a beam space section corresponding to the index feedback of the receiver 200 and a distance between the phased array antennas.

)를 생성할 수 있다.Specifically, the azimuth angle and the vertical angle can be viewed as the steering angle of the phased array antenna, and thus the beamforming weight calculation unit 130 is the azimuth angle of the beam space section corresponding to the index feedback of the receiver 200 as shown in Equation 2 below. And a parameter determined according to the distance between the upper and lower angles and the phased array antenna (

) Can be created.

이고, d_x 및 d_y는 각각 x축과 y축 위의 선형 배열 안테나 간의 거리를 나타낸다.In Equation 2, k is a constant determined according to the wavelength of the signal.

And d _x and d _y denote distances between the linear array antennas on the x-axis and y-axis, respectively.

)를 이용하여 위상 배열 안테나(n₁, n₂) 별 빔포밍 가중치(ω_{n1, n2})를 산출할 수 있다.The beamforming weight calculation unit 130 includes parameters such as Equation 2 (

) Can be used to calculate the beamforming weights (ω _{n1, n2} ) for each phased array antenna (n ₁ , n ₂ ).

In Equation 3, N ₁ and N ₂ denote the number of linear array antennas in the x-axis and y-axis directions, respectively. Here, the total number of antennas constituting the phased array antenna is N=N ₁ N ₂ .

The array factor calculator 150 may calculate the array factor AF of the phased array antenna by using the beamforming weight for each phased array antenna.

The array factor calculator 150 may calculate the array factor of the linear array antenna in the x-axis and y-axis directions as shown in Equations 4 and 5 below.

The array factor calculator 150 may calculate the array factor of the planar phased array antenna as shown in Equation 6 below using Equations 4 and 5.

5 is a control block diagram of the receiver shown in FIG. 1.

Referring to FIG. 5, the receiver 200 may include an average power measurement unit 210 and an index feedback unit 230.

The average power measurement unit 210 may measure the average power for each section of the beam steering pilot signal transmitted from the transmitter 100.

As described above, the transmitter 100 may transmit the beam steering pilot signal at a preset time (T _b ) interval according to the index order of the beamforming codebook. That is, the average power measurement unit 210 may receive a beam steering pilot signal from the transmitter 100 for each section of the entire beam space to which the index of the beamforming codebook is assigned.

The average power measurement unit 210 may measure the average power of the beam steering pilot signal for each section of the entire beam space to which the index of the beamforming codebook is assigned. This will be described with reference to FIG. 6.

6 is a diagram for explaining index feedback in the receiver illustrated in FIG. 5.

Referring to FIG. 6, the average power measurement unit 210 may measure average power at intervals of transmission time T _b of the beam steering pilot signal of the transmitter 100. For example, the average power measurement unit 210 may measure the power of a received signal using a rectifier and average the power measured at a predetermined time (T _b ) interval. Accordingly, the average power measurement unit 210 may measure the average power of the beam steering pilot signal for each section of the entire beam space to which the index of the beamforming codebook is assigned.

The average power measurement unit 210 may extract an index corresponding to a section having the maximum average power among sections of the entire beam space to which the index of the beamforming codebook is assigned. This section may be a transmission path of an energy signal transmitted from the transmitter 100 and corresponds to an optimal transmission path. In the case of FIG. 6, the average power measurement unit 210 may extract β ₄ .

The index feedback unit 230 may feed back an index assigned to a section of the beam space corresponding to the transmission path of the energy signal extracted by the average power measurement unit 210 to the transmitter 100.

The index feedback unit 230 may convert the extracted index into a codeword form and feed it back to the transmitter 100. This is to minimize power loss for bit errors during feedback.

The index feedback unit 230 may design a beamforming codeword by applying a gray code for each index of the beamforming codebook. An example of such a beamforming codeword is shown in Table 2 above.

The index feedback unit 230 may select a codeword corresponding to an index extracted from the beamforming codeword and feed it back to the transmitter 100. In the case of FIG. 6, the index feedback unit 230 feeds back a codeword value of “11000100” to the transmitter 100.

Hereinafter, a method of estimating a beamforming weight in a wireless power transmission system according to an embodiment of the present invention will be described.

The method of estimating a beamforming weight in the wireless power transmission system according to an embodiment of the present invention may be performed under substantially the same configuration as the wireless power transmission system 1 according to the embodiment of the present invention shown in FIG. 1. Therefore, the same components as those of the wireless power transmission system 1 of FIG. 1 are given the same reference numerals, and repeated descriptions are omitted.

7 is a flowchart illustrating a method of estimating a beamforming weight in a wireless power transmission system according to an embodiment of the present invention.

Referring to FIG. 7, a beam steering pilot signal according to a beamforming codebook may be transmitted from the transmitter 100 to the receiver 200 (S1000).

The transmitter 100 may be configured as a phased array antenna. The transmitter 100 may design a beamforming codebook by dividing a section of a 3D beam space and assigning an index to an azimuth angle and an upper and lower angle representing each section. The transmitter 100 may transmit the beam steering pilot signal to the receiver 200 at preset time intervals according to the index order of the beamforming codebook. That is, the transmitter 100 may transmit the pilot signal at preset time intervals for each section of the entire beam space. The transmitter 100 may transmit a synchronization signal to the receiver 200 before transmission of the beam steering pilot signal. This is for the receiver 200 to detect the start timing of the wireless power transmission frame.

The index of the beamforming codebook according to the beam steering pilot signal may be fed back from the receiver 200 to the transmitter 100 (S2000).

The receiver 200 may measure the average power of the beam steering pilot signal for each section of the entire beam space to which the index of the beamforming codebook is assigned. For example, the receiver 200 may measure the average power at intervals of transmission times (T _b ) of the beam steering pilot signal. The receiver 200 may measure the average power of the beam steering pilot signal for each section of the entire beam space to which the index of the beamforming codebook is assigned. The receiver 200 may extract an index corresponding to a section having the maximum average power among sections of the entire beam space to which the index of the beamforming codebook is assigned. This section may be a transmission path of an energy signal transmitted from the transmitter 100 and corresponds to an optimal transmission path.

The receiver 200 may convert the extracted index into a codeword form and feed it back to the transmitter 100. This is to minimize power loss for bit errors during feedback.

The transmitter 100 may calculate a beamforming weight using the index feedback of the receiver 200 (S3000), and calculate an array factor using the beamforming weight (S4000).

The transmitter 100 may calculate a beamforming weight according to Equations 2 and 3. In addition, the transmitter 100 may calculate the array factor using the beamforming weight according to Equations 4 to 6.

The beamforming weight estimation method in the wireless power transmission system of the present invention may be implemented as an application or implemented in the form of program instructions that can be executed through various computer components, and recorded in a computer-readable recording medium. The computer-readable recording medium may include program instructions, data files, data structures, etc. alone or in combination.

The program instructions recorded in the computer-readable recording medium may be specially designed and constructed for the present invention, and may be known and usable to those skilled in the computer software field.

Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magnetic-optical media such as floptical disks. media), and a hardware device specially configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules to perform processing according to the present invention, and vice versa.

Although the above has been described with reference to embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

1: wireless power transmission system
100: transmitter
200: receiver

Claims (8)

In the beamforming weight estimation method in a wireless power transmission system for transmitting a beamformed energy signal from a transmitter composed of a phased array antenna to a receiver,
Transmitting, by the transmitter, a beam steering pilot signal to the receiver in the order of a beamforming codebook to which an index is assigned by dividing a section of the entire beam space;
Selecting, by the receiver, a section of a beam space corresponding to a transmission path of an energy signal transmitted from the transmitter according to an average power of the beam steering pilot signal measured for each section of the entire beam space;
Feeding, by the receiver, an index assigned to a section of a beam space corresponding to a transmission path of the energy signal to the transmitter; And
And calculating, by the transmitter, a beamforming weight of the phased array antenna by finding a section of a beam space corresponding to the index feedback of the receiver in the beamforming codebook,
The receiver selecting a section of the beam space corresponding to the transmission path of the energy signal transmitted from the transmitter according to the average power of the beam steering pilot signal measured for each section of the entire beam space,
According to the section of the beam space divided by transmission at transmission time intervals of the beam steering pilot signal of the transmitter, the section in which the average power of the beam steering pilot signal is the maximum among the sections of the entire beam space corresponds to the transmission path of the energy signal. This is the step of selecting a section of the beam space,
The step of calculating, by the transmitter, a beamforming weight of the phased array antenna by finding a section of a beam space corresponding to the index feedback of the receiver in the beamforming codebook,
In the beamforming codebook, an azimuth angle and an upper and lower angle indicating a section of the beam space corresponding to the index feedback of the receiver, which is selected and fed back as a section with the maximum average power of the beam steering pilot signal among sections of the entire beam space, is extracted The step of doing; And
And calculating a beamforming weight for each of the phased array antennas by using the azimuth angle, the upper and lower angles, and the distance between the phased array antennas. delete The method of claim 1,
The step of transmitting, by the transmitter, a beam steering pilot signal in the order of a beamforming codebook in which an index is assigned by dividing a section of the entire beam space to the receiver,
A method for estimating beamforming weights in a wireless power transmission system comprising the step of designing the beamforming codebook by assigning an index to an azimuth angle and an elevation angle representing each section of the entire beam space. The method of claim 1,
The step of transmitting, by the transmitter, a beam steering pilot signal in the order of a beamforming codebook in which an index is assigned by dividing a section of the entire beam space to the receiver,
And transmitting a synchronization signal to the receiver so that the receiver can detect the start timing of the wireless power transmission frame before transmitting the beam steering pilot signal. The method of claim 1,
The step of the receiver feeding back an index assigned to a section of a beam space corresponding to a transmission path of the energy signal to the transmitter,
Designing a beamforming codeword by applying a gray code for each index of the beamforming codebook; And
Beamforming weight estimation in a wireless power transmission system comprising the step of selecting a codeword corresponding to an index assigned to a section of a beam space corresponding to a transmission path of the energy signal from the beamforming codeword and feeding back to the transmitter Way. delete In a wireless power transmission system for transmitting a beamformed energy signal from a transmitter consisting of a phased array antenna to a receiver,
The receiver transmits a beam steering pilot signal in the order of a beamforming codebook assigned an index by dividing a section of the entire beam space to receive an index feedback selected according to the average power of the beam steering pilot signal, and in the beamforming codebook A transmitter for calculating a beamforming weight of the phased array antenna by finding a section of the beam space corresponding to the index feedback of the receiver; And
Select a section of the beam space corresponding to the transmission path of the energy signal transmitted from the transmitter according to the average power of the beam steering pilot signal measured for each section of the entire beam space, and the beam space corresponding to the transmission path of the energy signal And a receiver that feeds back the index assigned to the interval of to the transmitter,
The receiver transmits the energy signal in a section in which the average power of the beam steering pilot signal is maximum among the sections of the entire beam space according to a section of the beam space divided by transmission at intervals of transmission time of the beam steering pilot signal of the transmitter. It is selected as a section of the beam space corresponding to the path,
The transmitter includes an azimuth angle indicating a section of the beam space corresponding to the index feedback of the receiver, which is selected and fed back as a section in which the average power of the beam steering pilot signal is the maximum among sections of the entire beam space in the beamforming codebook, and A wireless power transmission system for extracting an upper and lower angle, and calculating a beamforming weight for each phased array antenna by using the azimuth angle, the upper and lower angle, and a distance between the phased array antenna. The method of claim 7,
The transmitter,
A wireless power transmission system for transmitting a synchronization signal to the receiver so that the receiver can detect a start timing of a wireless power transmission frame before transmitting the beam steering pilot signal.

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