CN111917448A - Wave beam training method, device and system for millimeter wave communication and storage medium - Google Patents

Wave beam training method, device and system for millimeter wave communication and storage medium Download PDF

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CN111917448A
CN111917448A CN202010816437.8A CN202010816437A CN111917448A CN 111917448 A CN111917448 A CN 111917448A CN 202010816437 A CN202010816437 A CN 202010816437A CN 111917448 A CN111917448 A CN 111917448A
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antenna array
phase shift
base station
reflecting surface
intelligent
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CN111917448B (en
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王伟
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Shenzhen University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/04013—Intelligent reflective surfaces
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/145—Passive relay systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0632—Channel quality parameters, e.g. channel quality indicator [CQI]

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The invention discloses a wave beam training method, a device, a system and a storage medium for millimeter wave communication, wherein the method comprises the steps of receiving base station signals reflected by an intelligent reflecting surface according to different diffuse reflection modes according to a receiving antenna array; transforming phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values; calculating to obtain a plurality of first channel measurement values under different first phase shift values according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array in different diffuse reflection modes; and calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion. According to the method provided by the invention, a plurality of channel measurement values are obtained through the transformation of the phase shift vector of the receiving antenna array, and the optimal reflection angle of the intelligent reflecting surface can be calculated according to the plurality of channel measurement values, so that the technical problem that the optimal reflection angle of the intelligent reflecting surface cannot be estimated in the conventional beam training is solved.

Description

Wave beam training method, device and system for millimeter wave communication and storage medium
Technical Field
The invention relates to the technical field of millimeter wave communication, in particular to a method, a device and a system for beam training of millimeter wave communication and a storage medium.
Background
With the explosive growth of data traffic, millimeter wave (mmWave) has become a key technology for fifth generation mobile communication by virtue of its rich available frequency band. The first serious challenge in implementing millimeter wave communication is path loss, and in order to compensate for the serious path loss of millimeter wave transmission, a millimeter wave base station usually employs a large-scale antenna array for narrow-beam transmission, so that transmission energy can be effectively concentrated in a certain area or direction. However, the millimeter wave has a small wavelength, which determines its weak diffraction, refraction and reflection capabilities. Therefore, when the line-of-sight path of millimeter wave communication is blocked by an obstacle, communication thereof may be interrupted or the communication rate may be drastically decreased.
The intelligent reflecting surface is a plane composed of a large number of low-cost passive reflecting elements, and each element can independently change the phase and amplitude of an incident signal. The refraction loss of the intelligent transmitting surface is far lower than that of natural refraction surfaces of buildings, trees, people and the like. Therefore, the intelligent reflecting surface can well solve the shielding problem of the millimeter waves, so that the transmission path of the electromagnetic waves can bypass the shielding object to reach a user, thereby improving the communication quality and the coverage capability of a millimeter wave system.
The beam training is a key technology for realizing the initial access of a user in a millimeter wave system, and essentially, the basic idea of the beam training is to obtain an optimal transmitting angle/receiving angle through a beam space search method and user power measurement under the condition that a base station does not have any user prior information, so that beam alignment is realized. However, the existing beam training method based on beam search and the beam training method based on the hierarchical codebook only aim at the beam training of the transmitting end and the receiving end, and the optimal reflection angle of the intelligent reflecting surface cannot be estimated.
Disclosure of Invention
In view of this, embodiments of the present invention provide a method, an apparatus, a system, and a storage medium for beam training of millimeter wave communication, so as to solve the problem that the existing beam training method cannot estimate the optimal reflection angle of the intelligent reflection surface.
The technical scheme provided by the invention is as follows:
a first aspect of an embodiment of the present invention provides a beam training method for millimeter wave communication, including: receiving base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes according to the receiving antenna array; transforming phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values; calculating to obtain a plurality of first channel measurement values under different first phase shift values according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array in different diffuse reflection modes; and calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion.
Further, the beam training method for millimeter wave communication further includes: receiving signals which are transmitted by a base station transmitting antenna array and do not pass through an intelligent reflecting surface according to a receiving antenna array; transforming the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values; calculating to obtain a plurality of second channel measurement values under different second phase shift values according to signals which are transmitted by the receiving antenna array receiving base station transmitting antenna array and do not pass through the intelligent reflecting surface; and calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion.
Further, the beam training method for millimeter wave communication further includes: when the intelligent reflecting surfaces comprise a plurality of intelligent reflecting surfaces, one intelligent reflecting surface is sequentially activated, the other intelligent reflecting surfaces are closed, and the base station transmits signals to the activated intelligent reflecting surfaces; by adopting the millimeter wave communication beam training method in the first aspect of the embodiment of the invention, the optimal reflection angles of all intelligent reflection surfaces are calculated.
Further, the beam training method for millimeter wave communication further includes: and sending the optimal reflection angle of the intelligent reflection surface and the arrival angle and the emission angle of the line-of-sight path to a base station.
Further, calculating an optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and a maximum likelihood criterion, wherein the method comprises the following steps: splicing according to a plurality of first channel measurement values to obtain a first measurement vector; calculating the first measurement vector according to a maximum likelihood criterion to obtain a difference value between a departure angle from the intelligent reflecting surface to the user and an arrival angle from the base station to the intelligent reflecting surface and the arrival angle from the intelligent reflecting surface to the user; and/or calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion, wherein the method comprises the following steps: splicing according to the plurality of second channel measurement values to obtain a second measurement vector; and calculating the second measurement vector according to a maximum likelihood criterion to obtain a departure angle from the base station to the user and an arrival angle from the base station to the user.
A second aspect of the embodiments of the present invention provides a beam training apparatus for millimeter wave communication, including: the first receiving module is used for receiving base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes according to the receiving antenna array; the first transformation module is used for transforming the phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values; the first channel measurement module is used for calculating to obtain a plurality of first channel measurement values under different first phase shift values according to the path component reflected by the intelligent reflecting surface, the channel matrix without the assistance of the intelligent reflecting surface and the base station signal; and the first angle calculation module is used for calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion.
Further, the beam training apparatus for millimeter wave communication further includes: the second receiving module is used for receiving the signals which are transmitted by the base station transmitting antenna array and do not pass through the intelligent reflecting surface according to the receiving antenna array; the second transformation module is used for transforming the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values; the second channel measurement module is used for calculating to obtain a plurality of second channel measurement values under different second phase shift values according to the signals which are transmitted by the receiving antenna array receiving base station transmitting antenna array and do not pass through the intelligent reflecting surface; and the second angle calculation module is used for calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion.
A third aspect of the embodiments of the present invention provides a beam training system for millimeter wave communication, including: the system comprises a base station, an intelligent reflecting surface and a user side, wherein the base station directionally transmits signals to the intelligent reflecting surface; the intelligent reflecting surface receives the signals sent by the base station and reflects the signals to a receiving antenna array of the user side through different diffuse reflection modes; the user side transforms phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values, calculates according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array according to different diffuse reflection modes to obtain a plurality of first channel measurement values under different first phase shift values, and calculates according to the plurality of first channel measurement values and a maximum likelihood criterion to obtain the optimal reflection angle of the intelligent reflecting surface.
A fourth aspect of the embodiments of the present invention provides a computer-readable storage medium, where computer instructions are stored, where the computer instructions are configured to cause a computer to execute a beam training method for millimeter wave communication according to any one of the first aspect and the first aspect of the embodiments of the present invention.
A fifth aspect of an embodiment of the present invention provides an electronic device, including: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the beam training method for millimeter wave communication according to any one of the first aspect and the first aspect of the embodiments of the present invention.
The technical scheme provided by the invention has the following effects:
according to the millimeter wave communication beam training method, device, system and storage medium provided by the embodiment of the invention, an intelligent reflecting surface is adopted to reflect millimeter wave communication signals between a base station and a user terminal, the user terminal can simultaneously convert phase shift vectors of a receiving antenna array according to a preset random omnidirectional beam forming codebook, the user terminal can calculate to obtain a measured value of one channel every time the phase shift vectors are converted, the number of the calculated measured values of the channel can be set in a self-adaptive manner according to the channel condition and the signal-to-noise ratio, and finally, the optimal reflecting angle of the intelligent reflecting surface can be calculated according to a plurality of measured values of the channel. Therefore, the millimeter wave communication beam training system provided by the embodiment of the invention obtains a plurality of channel measurement values through the transformation of the phase shift vector of the receiving antenna array, and the optimal reflection angle of the intelligent reflection surface can be calculated through the plurality of channel measurement values, so that the technical problem that the optimal reflection angle of the intelligent reflection surface cannot be estimated through the existing beam training is solved.
The millimeter wave communication beam training method, the millimeter wave communication beam training device, the millimeter wave communication beam training system and the millimeter wave communication beam training storage medium provided by the embodiment of the invention can freely set the training length, namely the number of calculated channel measurement values according to parameters such as signal-to-noise ratio, channel sparsity and the like. When the signal-to-noise ratio is high and the channel sparsity is high, the training length can be set to be a smaller value; conversely, the training length may be increased accordingly. While the training length in the existing technology based on the hierarchical codebook and DFT codebook is not adjustable. Redundant training overhead is brought when the signal-to-noise ratio is high and the channel sparsity is high; under the conditions of low signal-to-noise ratio and low channel sparsity, the estimation of waveform code words is inaccurate, thereby causing beam misalignment. Therefore, the method, the device, the system and the storage medium for beam training of millimeter wave communication provided by the embodiment of the invention solve the technical problem that the training overhead is uncontrollable in the existing beam training process.
According to the millimeter wave communication beam training method, device, system and storage medium provided by the embodiment of the invention, channel measurement is carried out at a user side, and a base station can simultaneously carry out beam training with a plurality of users in a broadcasting (or broadcasting by means of an intelligent reflecting surface) mode. Thus, the training overhead does not increase as the number of users increases.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic view of an application scenario of a beam training system for millimeter wave communication according to an embodiment of the present invention;
FIG. 2 is a timing diagram for beam training of line-of-sight paths in accordance with an embodiment of the present invention;
fig. 3 is a block diagram of a beam training system for millimeter wave communication according to an embodiment of the present invention;
FIG. 4 is a timing diagram for beam training of the intelligent reflective surface according to an embodiment of the invention;
fig. 5 is a flowchart of a beam training method of millimeter wave communication according to an embodiment of the present invention;
fig. 6 is a flow chart of a beam training method of millimeter wave communication according to another embodiment of the present invention;
fig. 7 is a flowchart of a beam training method of millimeter wave communication according to another embodiment of the present invention;
fig. 8 is a flowchart of a beam training method of millimeter wave communication according to another embodiment of the present invention;
fig. 9 is a block diagram of a beam training apparatus for millimeter wave communication according to an embodiment of the present invention;
fig. 10 is a block diagram of a beam training apparatus for millimeter wave communication according to another embodiment of the present invention;
FIG. 11 is a schematic structural diagram of a computer-readable storage medium provided in accordance with an embodiment of the present invention;
fig. 12 is a schematic structural diagram of an electronic device provided in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic view of an application scenario according to an embodiment of the present invention. When the base station 1 communicates with the user side 3, the base station 1 can directionally transmit the pilot signal to the direction of the intelligent reflecting surface 2, and when the intelligent reflecting surface 2 is opened, the signal transmitted by the base station 1 can be reflected to the user side 3, so that the technical problem of communication interruption when a communication line-of-sight path between the base station 1 and the user side 3 is blocked by a barrier can be solved.
As shown in fig. 1, a beam training system for millimeter wave communication according to an embodiment of the present invention includes: the system comprises a base station 1, an intelligent reflecting surface 2 and a user side 3, wherein the base station 1 directionally transmits signals to the intelligent reflecting surface 2; the intelligent reflecting surface 2 receives signals sent by a base station and reflects the signals to a receiving antenna array of a user end 3 through different diffuse reflection modes; the user end 3 transforms the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values, calculates a plurality of first channel measurement values under different first phase shift values according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array according to different diffuse reflection modes, and calculates the optimal reflection angle of the intelligent reflecting surface according to the plurality of first channel measurement values and a maximum likelihood criterion.
Specifically, the base station 1 may directionally transmit a pilot toward the direction of the intelligent reflection surface through beam forming, wherein the pilot signal is a direct sequence spread spectrum signal that is continuously transmitted by the base station without modulation. Alternatively, the number of first channel measurements may be adaptively set according to channel conditions and signal-to-noise ratio.
The millimeter wave communication beam training system provided by the embodiment of the invention adopts the intelligent reflecting surface to reflect millimeter wave communication signals between the base station and the user side, meanwhile, the user side can transform phase shift vectors of the receiving antenna array according to the preset random omnidirectional beam forming codebook, and the user side can calculate to obtain the measured value of one channel every time the phase shift vectors are transformed, the number of the calculated measured values of the channel can be set in a self-adaptive manner according to the channel condition and the signal-to-noise ratio, and finally, the optimal reflecting angle of the intelligent reflecting surface can be calculated according to a plurality of measured values of the channel. Therefore, the millimeter wave communication beam training system provided by the embodiment of the invention obtains a plurality of channel measurement values through the transformation of the phase shift vector of the receiving antenna array, and the optimal reflection angle of the intelligent reflection surface can be calculated through the plurality of channel measurement values, thereby solving the technical problem that the existing beam training system cannot estimate the optimal reflection angle of the intelligent reflection surface.
The millimeter wave communication beam training system provided by the embodiment of the invention can freely set the training length, namely the number of the calculated channel measurement values according to the parameters such as the signal-to-noise ratio, the channel sparsity and the like. When the signal-to-noise ratio is high and the channel sparsity is high, the training length can be set to be a smaller value; conversely, the training length may be increased accordingly. While the training length in the existing technology based on the hierarchical codebook and DFT codebook is not adjustable. Redundant training overhead is brought when the signal-to-noise ratio is high and the channel sparsity is high; under the conditions of low signal-to-noise ratio and low channel sparsity, the estimation of waveform code words is inaccurate, thereby causing beam misalignment. Therefore, the millimeter wave communication beam training system provided by the embodiment of the invention solves the technical problem that the training overhead is uncontrollable in the existing beam training process.
In the millimeter wave communication beam training system provided by the embodiment of the invention, channel measurement is performed at a user side, and a base station can perform beam training simultaneously with a plurality of users in a broadcasting (or broadcasting by means of an intelligent reflecting surface) mode. Thus, the training overhead does not increase as the number of users increases.
In an embodiment, for the beam training system, all the intelligent reflecting surfaces may be closed first, and the arrival angle and departure angle of the line-of-sight path may be calculated. Specifically, a transmitting antenna array at the base station end adopts random omnidirectional beam forming to transmit a pilot frequency, wherein the pilot frequency can be a sine wave without information, and an equivalent baseband is 1; meanwhile, the base station transforms the phase shift vector of the transmit antenna array according to a preset random omni-directional beamforming codebook, which may be formed by a plurality of codeword sets, for example, the codebook may be represented as
Figure BDA0002631611640000081
I.e. the codebook consists of N groups of codewords
Figure BDA0002631611640000082
And (4) forming. Wherein the code word
Figure BDA0002631611640000083
Can be expressed as
Figure BDA0002631611640000084
Figure BDA0002631611640000085
I.e. a code word
Figure BDA0002631611640000086
Corresponding to a set of randomly generated
Figure BDA0002631611640000087
Wherein the phase value
Figure BDA0002631611640000088
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
When the transmitting antenna array performs the phase shift vector transformation, the user terminal also transforms the phase shift vector of the receiving antenna array according to a preset random omnidirectional beamforming codebook, specifically, the preset random omnidirectional beamforming codebook may also be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000089
Figure BDA00026316116400000810
I.e. the codebook consists of N groups of codewords
Figure BDA00026316116400000811
And (4) forming. Wherein the code word
Figure BDA00026316116400000812
Can be expressed as
Figure BDA00026316116400000813
Figure BDA00026316116400000814
I.e. a code word
Figure BDA00026316116400000815
Corresponding to a set of randomly generated
Figure BDA00026316116400000816
Wherein the phase value
Figure BDA00026316116400000817
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
Specifically, when the base station or the user end transforms the phase shift vector of the antenna array according to the codebook, the phase shifter inside the base station or the user end may control the phase of the signal according to the codebook, and when the phase shift vector is transformed, the phase shift vector may be transformed according to the codebook
Figure BDA00026316116400000818
Or
Figure BDA00026316116400000819
Is implemented.
When the base station and the user terminal convert each data codebook once phase shift vector, the user terminal can calculate a channel measurement value once, and after the conversion is completed, the user terminal can obtain a series of measurement values of the channel, so that the number of the channel measurement values is the same as the number N of the code words in the codebook, and the N value can be set adaptively according to the channel condition and the signal-to-noise ratio. Alternatively, the calculated channel measurement value may be represented by formula (1).
Figure BDA00026316116400000820
Figure BDA0002631611640000091
Wherein the content of the first and second substances,
Figure BDA0002631611640000092
for channel matrices without assistance of intelligent reflecting surfaces, byThe proportion of line-of-sight path component in millimeter wave channel is large
Figure BDA0002631611640000093
Is much larger than the non line-of-sight path channel component
Figure BDA0002631611640000094
Therefore, vnThe occupied components are small.
Figure BDA0002631611640000095
And
Figure BDA0002631611640000096
is the phase shift vector of the receive and transmit antennas, H is the Hermitian conjugate transpose.LosIs the path gain of the line-of-sight path,
Figure BDA0002631611640000097
and guiding vectors for the array of the base station and the user antenna array. Wherein the content of the first and second substances,
Figure BDA0002631611640000098
may be represented by formula (2) and formula (3), respectively.
Figure BDA0002631611640000099
Figure BDA00026316116400000910
NTx、NRxNumber of antennas, omega, for base stations, usersnIs white gaussian noise, and is a noise,
Figure BDA00026316116400000911
is the transmit power. As shown in fig. 2, θLoSIs the angle of arrival (AoA, angle of arrival) of the line of sight path (LoS), phiLoSIs the angle of departure of the line of sight path, vnIs a pilot signal component transmitted over a non-line of sight (NLoS). Specifically, for the beam training process of the line-of-sight path, the training timing of its base station, user, and channel measurements may be performed according to the timing shown in fig. 2.
In one embodiment, after the plurality of channel measurements are calculated, the arrival angle and departure angle of the line-of-sight path may be calculated based on the plurality of channel measurements and the maximum likelihood criterion. Firstly, the calculated N channel measurement values ynExpressed in vector form, the expression shown in equation (4) is obtained.
Figure BDA00026316116400000912
Wherein the content of the first and second substances,
Figure BDA00026316116400000913
Figure BDA00026316116400000914
Figure BDA00026316116400000915
is to be counted for N times
Figure BDA00026316116400000916
And
Figure BDA00026316116400000917
obtained by combining vectors obtained by the product of Kronecker (Kronecker product).
Figure BDA00026316116400000918
Medium represents conjugate, vec represents matrix vectorization, i.e. a matrix of M x N becomes a vector of MN x 1.
Will be provided with
Figure BDA0002631611640000101
Considering as a Gaussian distribution, according to the maximum likelihood criterion, the arrival of the line-of-sight path can be estimated according to the formula (5)Angle and departure angle.
Figure BDA0002631611640000102
Wherein the content of the first and second substances,
Figure BDA0002631611640000103
in an embodiment, when calculating the optimal reflection angle of the intelligent reflection surface, one intelligent reflection surface may be activated first, and the base station transmits the pilot frequency to the intelligent reflection surface directionally, and meanwhile, the intelligent reflection surface generates different diffuse reflection patterns through a preset random reflection codebook, and optionally, the preset random diffuse reflection codebook may be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000104
I.e. the codebook may also be composed of N groups of codewords
Figure BDA0002631611640000105
And (4) forming. Wherein the code word
Figure BDA0002631611640000106
Can be expressed as
Figure BDA0002631611640000107
I.e. a code word
Figure BDA0002631611640000108
Corresponding to a set of randomly generated
Figure BDA0002631611640000109
Wherein the phase value
Figure BDA00026316116400001010
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
When the intelligent reflecting surface reflects signals through different diffuse reflection modes, the user side changes the receiving day according to the preset random omnidirectional beam forming codebookThe phase shift vector of the line array, in particular for the predetermined random omni-directional beamforming codebook, may also be formed by a plurality of codeword sets, e.g. the codebook may be represented as
Figure BDA00026316116400001011
I.e. the codebook consists of N groups of codewords
Figure BDA00026316116400001012
And (4) forming. Wherein the code word
Figure BDA00026316116400001013
Can be expressed as
Figure BDA00026316116400001014
I.e. a code word
Figure BDA00026316116400001015
Corresponding to a set of randomly generated
Figure BDA00026316116400001016
Wherein the phase value
Figure BDA00026316116400001017
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
In an embodiment, for each diffuse reflection mode of the intelligent reflecting surface and each phase shift value of the receiving antenna array, the user end may calculate a channel measurement value once, and after the conversion is completed, the user end may obtain a series of measurement values of the channel, so that the number of the channel measurement values is the same as the number N of the codewords in the codebook, and the N value may be adaptively set according to the channel condition and the signal-to-noise ratio. Alternatively, the calculated channel measurement value may be represented by equation (6).
Figure BDA0002631611640000111
Wherein the content of the first and second substances,
Figure BDA0002631611640000112
is a component of the path reflected by the intelligent reflecting surface and is represented by a reflection vector
Figure BDA0002631611640000113
It is decided that,
Figure BDA0002631611640000114
is the transmit beamforming vector at the base station side,
Figure BDA0002631611640000115
for the channel gain of the reflected path,
Figure BDA0002631611640000116
directing vector, N, for array of reflecting elements of intelligent reflecting surfaceReThe number of reflective elements, i.e. the number of elements in the active intelligent reflective surface, is shown in FIG. 3, thetaReRx、φReRxThe arrival angle and departure angle theta from the intelligent reflecting surface to the user sideTxRe、φTxReThe arrival angle and departure angle of the base station to the intelligent reflecting surface.
In an embodiment, after the plurality of channel measurement values are obtained through calculation, an optimal transmission angle of a reflection path and an arrival angle of the intelligent reflection surface to the user may be calculated according to the plurality of channel measurement values and the maximum likelihood criterion, where the optimal transmission angle of the reflection path is a difference between an arrival angle of the base station to the intelligent reflection surface and a departure angle of the intelligent reflection surface to the user terminal.
Specifically, in the calculation, first, N channel measurement values x obtained by calculation are calculatednExpressed in vector form, the expression shown in equation (7) is obtained.
Figure BDA0002631611640000117
Wherein the content of the first and second substances,
Figure BDA0002631611640000118
Figure BDA0002631611640000119
will be provided with
Figure BDA00026316116400001110
And (3) regarding the obtained data as Gaussian distribution, and estimating the optimal emission angle of the reflection path and the arrival angle of the intelligent reflection surface to the user according to a formula (8) according to a maximum likelihood criterion.
Figure BDA0002631611640000121
In one embodiment, after the optimal reflection angle of one intelligent reflection surface is estimated, the above steps can be performed in a loop until the optimal reflection angles of all the intelligent reflection surfaces are calculated. Specifically, for the beam training process of the intelligent reflecting surface, the training sequence of the base station, the intelligent reflecting surface, the user and the channel measurement value can be performed according to the sequence shown in fig. 4.
An embodiment of the present invention further provides a beam training method for millimeter wave communication, and as shown in fig. 5, the beam training method includes the following steps:
step S101: receiving base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes according to the receiving antenna array; specifically, before calculating the optimal reflection angle of the intelligent reflection surface, the intelligent reflection surface may be activated; when the base station directionally transmits the pilot signal to the intelligent reflecting surface, the intelligent reflecting surface generates different diffuse reflection modes through a preset random diffuse reflection codebook, optionally, the preset random diffuse reflection codebook may be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000122
I.e. the codebook may also be composed of N groups of codewords
Figure BDA0002631611640000123
And (4) forming. Wherein the code word
Figure BDA0002631611640000124
Can be expressed as
Figure BDA0002631611640000125
I.e. a code word
Figure BDA0002631611640000126
Corresponding to a set of randomly generated
Figure BDA0002631611640000127
Wherein the phase value
Figure BDA0002631611640000128
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi. The intelligent reflecting surface can reflect the base station signals according to different diffuse reflection modes.
Step S102: transforming phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values; specifically, when the receiving antenna array of the user terminal receives the base station signal, the phase shift vector of the receiving antenna array may be transformed according to a preset random omnidirectional beamforming codebook, and specifically, the preset random omnidirectional beamforming codebook may also be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000129
I.e. the codebook consists of N groups of codewords
Figure BDA00026316116400001210
And (4) forming. Wherein the code word
Figure BDA00026316116400001211
Can be expressed as
Figure BDA00026316116400001212
I.e. a code word
Figure BDA00026316116400001213
Corresponding to a set of randomly generated
Figure BDA00026316116400001214
Wherein the phase value
Figure BDA00026316116400001215
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
Step S103: calculating to obtain a plurality of first channel measurement values under different first phase shift values according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array in different diffuse reflection modes; specifically, for each diffuse reflection mode of the intelligent reflecting surface and each phase shift value of the receiving antenna array, the user end may calculate a channel measurement value once, and after the conversion is completed, the user end may obtain measurement values of a series of channels, so that the number of the channel measurement values is the same as the number N of the codewords in the codebook, and the N value may be adaptively set according to the channel condition and the signal-to-noise ratio.
Alternatively, the calculated channel measurement value may be represented by equation (6).
Figure BDA0002631611640000131
Wherein the content of the first and second substances,
Figure BDA0002631611640000132
is a component of the path reflected by the intelligent reflecting surface and is represented by a reflection vector
Figure BDA0002631611640000133
It is decided that,
Figure BDA0002631611640000134
is the transmit beamforming vector at the base station side,
Figure BDA0002631611640000135
for the channel gain of the reflected path,
Figure BDA0002631611640000136
directing vector, N, for array of reflecting elements of intelligent reflecting surfaceReThe number of reflective elements, i.e. the number of elements in the active intelligent reflective surface, is shown in FIG. 3, thetaReRx、φReRxThe arrival angle and departure angle theta from the intelligent reflecting surface to the user sideTxRe、φTxReThe arrival angle and departure angle of the base station to the intelligent reflecting surface.
Specifically, for the beam training process of the intelligent reflecting surface, the training sequence of the base station, the intelligent reflecting surface, the user and the channel measurement value can be performed according to the sequence shown in fig. 4.
Step S104: and calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion. Specifically, after the plurality of channel measurement values are obtained through calculation, an optimal transmission angle of the reflection path and an arrival angle from the intelligent reflection surface to the user can be calculated according to the plurality of channel measurement values and the maximum likelihood criterion, where the optimal transmission angle of the reflection path is a difference between an arrival angle from the base station to the intelligent reflection surface and a departure angle from the intelligent reflection surface to the user side.
Specifically, in the calculation, first, N channel measurement values x obtained by calculation are calculatednExpressed in vector form, the expression shown in equation (7) is obtained.
Figure BDA0002631611640000141
Wherein the content of the first and second substances,
Figure BDA0002631611640000142
Figure BDA0002631611640000143
will be provided with
Figure BDA0002631611640000144
Considering a gaussian distribution, according to the maximum likelihood criterion, the optimal emission angle of the reflection path can be estimated according to equation (8) to obtainAnd the arrival angle of the intelligent reflecting surface to the user.
Figure BDA0002631611640000145
According to the millimeter wave communication beam training method provided by the embodiment of the invention, millimeter wave communication signals between a base station and a user terminal are reflected by an intelligent reflecting surface, the user terminal can convert phase shift vectors of a receiving antenna array according to a preset random omnidirectional beam forming codebook, the user terminal can calculate to obtain a measured value of a channel every time the phase shift vectors are converted, the number of the calculated measured values of the channel can be set in a self-adaptive manner according to the channel condition and the signal-to-noise ratio, and finally the optimal reflecting angle of the intelligent reflecting surface can be calculated according to a plurality of measured values of the channel. Therefore, according to the beam training method for millimeter wave communication provided by the embodiment of the invention, the plurality of channel measurement values are obtained through the transformation of the phase shift vector of the receiving antenna array, and the optimal reflection angle of the intelligent reflection surface can be calculated according to the plurality of channel measurement values, so that the technical problem that the optimal reflection angle of the intelligent reflection surface cannot be estimated by the existing beam training method is solved.
The wave beam training method for millimeter wave communication provided by the embodiment of the invention can freely set the training length, namely the number of the calculated channel measurement values according to the parameters such as the signal-to-noise ratio, the channel sparsity and the like. When the signal-to-noise ratio is high and the channel sparsity is high, the training length can be set to be a smaller value; conversely, the training length may be increased accordingly. While the training length in the existing technology based on the hierarchical codebook and DFT codebook is not adjustable. Redundant training overhead is brought when the signal-to-noise ratio is high and the channel sparsity is high; under the conditions of low signal-to-noise ratio and low channel sparsity, the estimation of waveform code words is inaccurate, thereby causing beam misalignment. Therefore, the beam training method for millimeter wave communication provided by the embodiment of the invention solves the technical problem that the training overhead is uncontrollable in the existing beam training process.
In the millimeter wave communication beam training method provided by the embodiment of the invention, channel measurement is performed at a user side, and a base station can perform beam training simultaneously with a plurality of users in a broadcasting (or broadcasting by means of an intelligent reflecting surface) mode. Thus, the training overhead does not increase as the number of users increases.
In an embodiment, as shown in fig. 6, the method for beam training of millimeter wave communication further includes the following steps:
step S201: receiving signals which are transmitted by a base station transmitting antenna array and do not pass through an intelligent reflecting surface according to a receiving antenna array; specifically, for beam training of millimeter wave communication, in addition to the optimal reflection angle of the intelligent reflection surface, the arrival angle and departure angle of the line-of-sight path at the time of turning off the intelligent reflection surface need to be calculated. First, all the intelligent reflecting surfaces can be closed first, and the transmitting antenna array of the base station can directly transmit pilot signals to the user side by adopting random omnidirectional beam forming. The signal may be a direct sequence spread spectrum signal that is continuously transmitted by the base station without modulation.
Step S202: and transforming the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values.
In an embodiment, when the base station transmits a signal, the phase shift vector of the transmit antenna array may be transformed according to a preset random omni-directional beamforming codebook, where the preset random omni-directional beamforming codebook may be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000151
I.e. the codebook consists of N groups of codewords
Figure BDA0002631611640000152
And (4) forming. Wherein the code word
Figure BDA0002631611640000153
Can be expressed as
Figure BDA0002631611640000154
I.e. a code word
Figure BDA0002631611640000155
Corresponding to a set of randomly generated
Figure BDA0002631611640000156
Wherein the phase value
Figure BDA0002631611640000157
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
Optionally, when the transmitting antenna array performs the phase shift vector transformation, the receiving antenna array also transforms the phase shift vector of the receiving antenna array according to a preset random omnidirectional beamforming codebook, specifically, for the preset random omnidirectional beamforming codebook, the codebook may also be formed by a plurality of codeword sets, for example, the codebook may be represented as a codebook
Figure BDA0002631611640000161
I.e. the codebook consists of N groups of codewords
Figure BDA0002631611640000162
And (4) forming. Wherein the code word
Figure BDA0002631611640000163
Can be expressed as
Figure BDA0002631611640000164
I.e. a code word
Figure BDA0002631611640000165
Corresponding to a set of randomly generated
Figure BDA0002631611640000166
Wherein the phase value
Figure BDA0002631611640000167
Obeying some random distribution, e.g. a uniform distribution between 0-2 pi.
Specifically, when the base station or the user end transforms the phase shift vector of the antenna array according to the codebook, the phase shifter inside the base station or the user end can control the phase of the signal according to the codebook, and the phase shift vector is then adjustedWhen the transformation is performed, the transformation can be performed according to the codebook
Figure BDA0002631611640000168
Or
Figure BDA0002631611640000169
Is implemented.
Step S203: calculating to obtain a plurality of second channel measurement values under different second phase shift values according to signals which are transmitted by the receiving antenna array receiving base station transmitting antenna array and do not pass through the intelligent reflecting surface; specifically, when the base station and the user terminal each convert a phase shift vector once according to the codebook, the user terminal can calculate a channel measurement value once, and after the conversion is completed, the user terminal can obtain a series of measurement values of the channel, so that the number of the channel measurement values is the same as the number N of the codewords in the codebook, and the N value can be adaptively set according to the channel condition and the signal-to-noise ratio. Alternatively, the calculated channel measurement value may be represented by formula (1).
Figure BDA00026316116400001610
Wherein the content of the first and second substances,
Figure BDA00026316116400001611
the channel matrix is a channel matrix without the assistance of an intelligent reflecting surface, and the proportion of the line-of-sight path component in a millimeter wave channel is large, so that the line-of-sight path channel component
Figure BDA00026316116400001612
Is much larger than the non line-of-sight path channel component
Figure BDA00026316116400001613
Thus, vnThe occupied components are small.
Figure BDA00026316116400001614
And
Figure BDA00026316116400001615
is the phase shift vector of the receive and transmit antennas, H is the Hermitian conjugate transpose.LosIs the path gain of the line-of-sight path,
Figure BDA00026316116400001616
and guiding vectors for the array of the base station and the user antenna array. Wherein the content of the first and second substances,
Figure BDA0002631611640000171
may be represented by formula (2) and formula (3), respectively.
Figure BDA0002631611640000172
Figure BDA0002631611640000173
NTx、NRxNumber of antennas, omega, for base stations, usersnIs white gaussian noise, and is a noise,
Figure BDA0002631611640000174
is the transmit power. ThetaLoSIs the angle of arrival (AoA, angle of arrival) of the line of sight path (LoS), φLoSIs the angle of departure of the visual path of the data, vnIs a pilot signal component transmitted over a non-line of sight (NLoS).
Step S204: and calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion. Specifically, after the plurality of channel measurement values are calculated, the arrival angle and departure angle of the line-of-sight path may be calculated according to the plurality of channel measurement values and the maximum likelihood criterion. Firstly, the calculated N channel measurement values ynExpressed in vector form, the expression shown in equation (4) is obtained.
Figure BDA0002631611640000175
Wherein the content of the first and second substances,
Figure BDA0002631611640000176
Figure BDA0002631611640000177
Figure BDA0002631611640000178
is to be counted for N times
Figure BDA0002631611640000179
And
Figure BDA00026316116400001710
obtained by combining vectors obtained by the product of Kronecker (Kronecker product).
Figure BDA00026316116400001711
Medium represents conjugate, vec represents matrix vectorization, i.e. a matrix of M x N becomes a vector of MN x 1.
Will be provided with
Figure BDA00026316116400001712
And (3) regarding the obtained data as Gaussian distribution, and according to a maximum likelihood criterion, estimating and obtaining the arrival angle and the departure angle of the line-of-sight path according to a formula (5).
Figure BDA00026316116400001713
Wherein the content of the first and second substances,
Figure BDA00026316116400001714
in an embodiment, as shown in fig. 7, the method for beam training of millimeter wave communication further includes the following steps:
step S301: when the intelligent reflecting surfaces comprise a plurality of intelligent reflecting surfaces, one intelligent reflecting surface is activated in sequence, and the rest intelligent reflecting surfaces are closed.
Step S302: and calculating to obtain the optimal reflection angles of all intelligent reflection surfaces by adopting the millimeter wave communication beam training method from the step S101 to the step S104.
Specifically, when a plurality of intelligent reflecting surfaces are provided, after the optimal reflecting angle of one intelligent reflecting surface is estimated, the steps S101 to S104 may be executed in a loop until the optimal reflecting angles of all the intelligent reflecting surfaces are calculated.
In an embodiment, the method for beam training of millimeter wave communication further includes the following steps: and sending the optimal reflection angle of the intelligent reflection surface and the arrival angle and the emission angle of the line-of-sight path to a base station. Specifically, after the user side estimates the corresponding angle, the corresponding parameter may be fed back to the base station through the low frequency feedback link.
In an embodiment, as shown in fig. 8, the method for training millimeter wave communication beams according to the embodiment of the present invention may be implemented as follows, first closing all the intelligent reflection planes, the base station sending a pilot signal to the user side by using random omnidirectional beam forming, the user side receiving signals received by the antenna array, and obtaining a series of channel measurement values by changing the phase shift vector; then activating one intelligent reflecting surface, closing the other intelligent reflecting surfaces, directionally transmitting pilot frequency to the intelligent reflecting surface by the base station, reflecting base station signals by the intelligent reflecting surface in a random diffuse reflection mode, receiving the signals by the user side, and calculating to obtain a series of channel measurement values through the change of phase shift vectors; and the user side estimates the arrival angle and the departure angle of the line-of-sight path, the optimal reflection angle of the intelligent reflection surface and the incident angle from the reflection surface to the user according to the calculated different channel measurement values. After all the parameters are calculated, the user terminal can feed back all the parameters to the base station through the low-frequency feedback link.
An embodiment of the present invention further provides a beam training apparatus for millimeter wave communication, and as shown in fig. 9, the beam training apparatus includes:
the first receiving module 10 is configured to receive, according to the receiving antenna array, base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes; for details, refer to the related description of step S101 in the above method embodiment.
A first transformation module 20, configured to transform a phase shift vector of a receiving antenna array according to a preset random omnidirectional beamforming codebook to obtain a plurality of first phase shift values; for details, refer to the related description of step S102 in the above method embodiment.
The first channel measurement module 30 is configured to calculate, according to base station signals reflected by different diffuse reflection modes, a plurality of first channel measurement values under different first phase shift values by using the intelligent reflection surface received by the receiving antenna array; for details, refer to the related description of step S103 in the above method embodiment.
And the first angle calculation module 40 is used for calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion. For details, refer to the related description of step S104 in the above method embodiment.
The millimeter wave communication beam training device provided by the embodiment of the invention adopts the intelligent reflecting surface to reflect millimeter wave communication signals between the base station and the user side, meanwhile, the user side can transform phase shift vectors of the receiving antenna array according to the preset random omnidirectional beam forming codebook, and the user side can calculate to obtain the measured value of one channel every time the phase shift vectors are transformed, the number of the calculated measured values of the channel can be set in a self-adaptive manner according to the channel condition and the signal-to-noise ratio, and finally, the optimal reflecting angle of the intelligent reflecting surface can be calculated according to a plurality of measured values of the channel. Therefore, the millimeter wave communication beam training device provided by the embodiment of the invention obtains a plurality of channel measurement values through the transformation of the phase shift vector of the receiving antenna array, and the optimal reflection angle of the intelligent reflection surface can be calculated according to the plurality of channel measurement values, so that the technical problem that the optimal reflection angle of the intelligent reflection surface cannot be estimated in the conventional beam training is solved.
The millimeter wave communication beam training device provided by the embodiment of the invention can freely set the training length, namely the number of the calculated channel measurement values according to the parameters such as the signal-to-noise ratio, the channel sparsity and the like. When the signal-to-noise ratio is high and the channel sparsity is high, the training length can be set to be a smaller value; conversely, the training length may be increased accordingly. While the training length in the existing technology based on the hierarchical codebook and DFT codebook is not adjustable. Redundant training overhead is brought when the signal-to-noise ratio is high and the channel sparsity is high; under the conditions of low signal-to-noise ratio and low channel sparsity, the estimation of waveform code words is inaccurate, thereby causing beam misalignment. Therefore, the beam training device for millimeter wave communication provided by the embodiment of the invention solves the technical problem that the training overhead is uncontrollable in the existing beam training process.
According to the millimeter wave communication beam training device provided by the embodiment of the invention, channel measurement is carried out at a user side, and a base station can carry out beam training with a plurality of users simultaneously in a broadcasting (or broadcasting by means of an intelligent reflecting surface) mode. Thus, the training overhead does not increase as the number of users increases.
In an embodiment, as shown in fig. 10, the beam training apparatus for millimeter wave communication further includes:
the second receiving module 21 is configured to receive, according to the receiving antenna array, a signal that is transmitted by the base station transmitting antenna array and does not pass through the intelligent reflecting surface; for details, refer to the related description of step S201 in the above method embodiment.
The second transformation module 22 is configured to transform the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values; for details, refer to the related description of step S202 in the above method embodiment.
The second channel measurement module 23 is configured to calculate, according to the signal that is transmitted by the receiving antenna array and does not pass through the intelligent reflecting surface, a plurality of first channel measurement values under different first phase shift values; for details, refer to the related description of step S203 in the above method embodiment.
And the second angle calculation module 24 is configured to calculate an arrival angle and a launch angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion. For details, refer to the related description of step S204 in the above method embodiment.
For a detailed description of the function of the beam training apparatus for millimeter wave communication according to the embodiment of the present invention, reference is made to the description of the beam training method for millimeter wave communication in the above embodiment.
An embodiment of the present invention further provides a storage medium, as shown in fig. 11, on which a computer program 601 is stored, where the instructions, when executed by a processor, implement the steps of the beam training method for millimeter wave communication in the foregoing embodiment. The storage medium is also stored with audio and video stream data, characteristic frame data, an interactive request signaling, encrypted data, preset data size and the like. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD) or a Solid State Drive (SSD), etc.; the storage medium may also comprise a combination of memories of the kind described above.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a flash Memory (FlashMemory), a Hard Disk (Hard Disk Drive, abbreviated as HDD), a Solid-State Drive (SSD), or the like; the storage medium may also comprise a combination of memories of the kind described above.
An embodiment of the present invention further provides an electronic device, as shown in fig. 12, the electronic device may include a processor 51 and a memory 52, where the processor 51 and the memory 52 may be connected by a bus or in another manner, and fig. 12 takes the example of connection by a bus as an example.
The processor 51 may be a Central Processing Unit (CPU). The Processor 51 may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components, or combinations thereof.
The memory 52, which is a non-transitory computer readable storage medium, may be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as the corresponding program instructions/modules in the embodiments of the present invention. The processor 51 executes various functional applications and data processing of the processor by running non-transitory software programs, instructions and modules stored in the memory 52, that is, implements the beam training method of millimeter wave communication in the above-described method embodiments.
The memory 52 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created by the processor 51, and the like. Further, the memory 52 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory 52 may optionally include memory located remotely from the processor 51, and these remote memories may be connected to the processor 51 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The one or more modules are stored in the memory 52 and, when executed by the processor 51, perform a beam training method for millimeter wave communication as in the embodiments of fig. 5-8.
The details of the electronic device may be understood by referring to the corresponding descriptions and effects in the embodiments shown in fig. 5 to fig. 8, which are not described herein again.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims (10)

1. A method for beam training of millimeter wave communication, comprising:
receiving base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes according to the receiving antenna array;
transforming phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values;
calculating to obtain a plurality of first channel measurement values under different first phase shift values according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array in different diffuse reflection modes;
and calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion.
2. The beam training method for millimeter wave communication according to claim 1, further comprising:
receiving signals which are transmitted by a base station transmitting antenna array and do not pass through an intelligent reflecting surface according to a receiving antenna array;
transforming the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values;
calculating to obtain a plurality of second channel measurement values under different second phase shift values according to signals which are transmitted by the receiving antenna array receiving base station transmitting antenna array and do not pass through the intelligent reflecting surface;
and calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion.
3. The beam training method of millimeter wave communication according to claim 1,
when the intelligent reflecting surfaces comprise a plurality of intelligent reflecting surfaces, one intelligent reflecting surface is sequentially activated, the other intelligent reflecting surfaces are closed, and the base station transmits signals to the activated intelligent reflecting surfaces;
the millimeter wave communication beam training method of claim 1, wherein the optimal reflection angles of all intelligent reflecting surfaces are calculated.
4. The method of beam training for millimeter wave communication according to claim 2, further comprising: and sending the optimal reflection angle of the intelligent reflection surface and the arrival angle and the emission angle of the line-of-sight path to a base station.
5. The beam training method of millimeter wave communication according to claim 2,
calculating the optimal reflection angle of the intelligent reflection surface according to a plurality of first channel measurement values and a maximum likelihood criterion, wherein the method comprises the following steps:
splicing according to a plurality of first channel measurement values to obtain a first measurement vector;
calculating the first measurement vector according to a maximum likelihood criterion to obtain a difference value between a departure angle from the intelligent reflecting surface to the user and an arrival angle from the base station to the intelligent reflecting surface and the arrival angle from the intelligent reflecting surface to the user;
and/or calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion, wherein the method comprises the following steps:
splicing according to the plurality of second channel measurement values to obtain a second measurement vector;
and calculating the second measurement vector according to a maximum likelihood criterion to obtain a departure angle from the base station to the user and an arrival angle from the base station to the user.
6. A beam training apparatus for millimeter wave communication, comprising:
the first receiving module is used for receiving base station signals reflected by the intelligent reflecting surface according to different diffuse reflection modes according to the receiving antenna array;
the first transformation module is used for transforming the phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values;
the first channel measurement module is used for calculating to obtain a plurality of first channel measurement values under different first phase shift values according to the path component reflected by the intelligent reflecting surface, the channel matrix without the assistance of the intelligent reflecting surface and the base station signal;
and the first angle calculation module is used for calculating the optimal reflection angle of the intelligent reflection surface according to the plurality of first channel measurement values and the maximum likelihood criterion.
7. The beam training apparatus for millimeter wave communication according to claim 6, further comprising:
the second receiving module is used for receiving the signals which are transmitted by the base station transmitting antenna array and do not pass through the intelligent reflecting surface according to the receiving antenna array;
the second transformation module is used for transforming the phase shift vector of the transmitting antenna array and the phase shift vector of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of second phase shift values;
the second channel measurement module is used for calculating to obtain a plurality of second channel measurement values under different second phase shift values according to the signals which are transmitted by the receiving antenna array receiving base station transmitting antenna array and do not pass through the intelligent reflecting surface;
and the second angle calculation module is used for calculating the arrival angle and the emission angle of the line-of-sight path according to the plurality of second channel measurement values and the maximum likelihood criterion.
8. A beam training system for millimeter wave communication, comprising: a base station, an intelligent reflecting surface and a user terminal,
the base station directionally transmits signals to the intelligent reflecting surface;
the intelligent reflecting surface receives the signals sent by the base station and reflects the signals to a receiving antenna array of the user side through different diffuse reflection modes;
the user side transforms phase shift vectors of the receiving antenna array according to a preset random omnidirectional beam forming codebook to obtain a plurality of first phase shift values, a plurality of first channel measurement values under different first phase shift values are obtained through calculation according to base station signals reflected by the intelligent reflecting surface received by the receiving antenna array according to different diffuse reflection modes and the signals, and the optimal reflection angle of the intelligent reflecting surface is obtained through calculation according to the plurality of first channel measurement values and a maximum likelihood criterion.
9. A computer-readable storage medium storing computer instructions for causing a computer to perform the beam training method for millimeter wave communication according to any one of claims 1 to 5.
10. An electronic device, comprising: a memory and a processor, the memory and the processor being communicatively coupled to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the beam training method for millimeter wave communication according to any of claims 1 to 5.
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