Systems and methods for updating beamforming codebooks

Abstract

A system and method for updating a beamforming codebook is provided. A wireless communication device includes a processing circuit configured to: receive a first directional electromagnetic signal including a beam scanning reference symbol for a previous beam scanning period from an antenna array during a previous cycle; calculate an estimated combined channel; estimate a primary angle of arrival (AoA) of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different angles of arrival (AoA); construct an updated beamforming codebook based on the estimated primary AoA and one or more residual AoAs spaced apart from the estimated primary AoA; receive a second directional electromagnetic signal including a data symbol at the antenna array during a current cycle; determine a beamforming vector for data reception of the second directional electromagnetic signal based on the updated beamforming codebook; and detect the data symbol in the second directional electromagnetic signal based on the determined beamforming vector.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 005,850, filed in the U.S. Patent and Trademark Office on April 6, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] Aspects of the embodiments of the present disclosure are directed to systems and methods for updating a beamforming codebook for angle of arrival estimation using compressed sensing in wireless communications. Background Art

[0004] In a beamforming wireless communication system, a transmitter can control or direct the direction in which electromagnetic waves are transmitted, and can shape or form these electromagnetic waves into relatively narrow beams. These beams can be formed using an array of antennas, where different antennas of the array are provided with time-shifted or phase-shifted versions of the signal, and a combination of constructive and destructive interference causes the signal to be concentrated in a particular direction. Beamforming achieves spatial diversity of the electromagnetic waves (e.g., essentially the opposite of omnidirectional transmission) and also allows the beam to be steered as its relative direction to the receiver changes over time. For example, beamforming allows more communication channels to operate simultaneously—e.g., receivers located in different directions relative to the transmitter can receive different signals from the same transceiver at the same carrier frequency or in overlapping frequency bands. Beamforming may be particularly applicable to millimeter wave (mmWave) communications and massive multiple-input, multiple-output (MIMO) systems.

[0005] In a hybrid beamforming system, beam scanning can be periodically performed to prevent poor link budgets by determining the optimal transmission direction or vector between a transmitter and a receiver, where the optimal transmission vector is selected from a beamforming codebook, or beam codebook. The beamforming codebook includes weights for decoding received directional electromagnetic signals (e.g., wireless signals or radio signals), where different weights correspond to different possible beamforming vectors (e.g., electromagnetic signals received from different directions).

[0006] Hybrid beamforming systems decode directional electromagnetic signals received at an antenna array by combining the received signal with the weights of a beamforming codebook and selecting the dominant direction (e.g., the signal and weight combination with the highest power or signal-to-noise ratio). The performance of a beamforming wireless transmission system depends on the quality of the beamforming codebook, such as how closely the codebook's direction (at least one direction) aligns with the actual direction of the electromagnetic signal arriving at the receiver antenna array. Summary of the Invention

[0007] Aspects of the embodiments of the present disclosure relate to systems and methods for updating a beamforming codebook according to changes in transmission conditions and based on a history of angular directions of arrival for a given transmitter using compressed sensing techniques.

[0008] According to one embodiment of the present disclosure, a method for updating a beamforming codebook includes: receiving, at an antenna array of a wireless communication device during a previous cycle, a first directional electromagnetic signal including a beam scanning reference symbol for a previous beam scanning period; calculating, by a processing circuit of the wireless communication device, an estimated combined channel based on the received first directional electromagnetic signal; estimating, by the processing circuit, a main angle of arrival of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different angles of arrival (AoA); and calculating, by the processing circuit, one or more residual angles of arrival spaced apart from the estimated main angle of arrival; constructing, by the processing circuit, an updated beamforming codebook based on the estimated main angle of arrival and the one or more residual angles of arrival; receiving, at the antenna array during a current cycle, a second directional electromagnetic signal including a data symbol; determining, based on the updated beamforming codebook, a beamforming vector for data reception of the second directional electromagnetic signal; and detecting, by the processing circuit, the data symbol in the second directional electromagnetic signal based on the determined beamforming vector.

[0009] The updated beamforming codebook may consist of two beamforming vectors,

[0010] wherein the main AOA of the first directional electromagnetic signal is estimated The steps include calculating the following formula:

[0011]

[0012] in,

[0013]

[0014] as well as

[0015]

[0016] where Y is the estimated combined channel, and and is an estimated analog channel corresponding to two antenna elements of the antenna array, wherein the one or more residual angles of arrival correspond to a beamforming vector, wherein the antenna array has an even number of antenna elements, and wherein the residual angles of arrival according to is calculated, and

[0017] The updated beamforming codebook Wt It is calculated according to the following formula:

[0018]

[0019] The updated beamforming codebook may include three or more beamforming vectors.

[0020] Estimating the primary AOA of the first directional electromagnetic signal The steps may include calculating the following formula:

[0021]

[0022]

[0023]

[0024] where Y is the estimated combined channel, and is the set of angles in the neighborhood around the chosen search angle b*.

[0025] Selected search angle b * Can be selected according to the following formula:

[0026]

[0027] in,

[0028]

[0029] Selected search angle b * The selected angle may be based on an estimated main angle of arrival of a third directional electromagnetic signal received in a previous beam scanning period.

[0030] In the selected search angle b * The set of angles in the surrounding neighborhood It can be calculated by the following formula:

[0031]

[0032] Among them, N will The number of angles in is controlled to be 2N+1, and where Δ is Angular resolution of the angles in .

[0033] The number N of antenna elements in the antenna array R may be an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and the one or more remaining angles of arrival It can be calculated according to the following formula:

[0034]

[0035] in, is the estimated principal angle of arrival of the first directional electromagnetic signal.

[0036] The number N of antenna elements in the antenna array R may not be an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and wherein the one or more remaining angles of arrival are selected from the angle constraint set was selected, among which,

[0037]

[0038] The step of determining a beamforming vector for data reception of the second directional electromagnetic signal may include selecting the beamforming vector for data reception from the updated beamforming codebook without performing channel estimation.

[0039] The step of determining a beamforming vector for data reception of the second directional electromagnetic signal may comprise explicitly calculating the beamforming vector based on a channel estimate of the second directional electromagnetic signal and based on the updated beamforming codebook.

[0040] According to one embodiment of the present disclosure, a wireless communication device is configured to update a beamforming codebook, the wireless communication device comprising: an antenna array; a processing circuit configured to receive a signal from the antenna array and configured to: receive a first directional electromagnetic signal including a beam scanning reference symbol for a previous beam scanning period at the antenna array during a previous cycle; calculate an estimated combined channel based on the received first directional electromagnetic signal; estimate a main arrival angle of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different angles of arrival (AoA); and calculate one or more residual arrival angles spaced apart from the estimated main arrival angle; construct an updated beamforming codebook based on the estimated main arrival angle and the one or more residual arrival angles; receive a second directional electromagnetic signal including a data symbol at the antenna array during a current cycle; determine a beamforming vector for data reception of the second directional electromagnetic signal based on the updated beamforming codebook; and detect the data symbol in the second directional electromagnetic signal based on the determined beamforming vector.

[0041] The updated beamforming codebook may be composed of two beamforming vectors, wherein the processing circuit is configured to estimate the main arrival angle of the first directional electromagnetic signal by calculating the following equation:

[0042]

[0043] in,

[0044]

[0045] as well as

[0046]

[0047] where Y is the estimated combined channel, and and is an estimated simulated channel corresponding to two antenna elements of the antenna array, wherein the one or more residual angles of arrival correspond to a beamforming vector, wherein the antenna array has an even number of antenna elements, and wherein the residual angles of arrival according to is calculated, and wherein the updated beamforming codebook W t It is calculated according to the following formula:

[0048]

[0049] The updated beamforming codebook may include three or more beamforming vectors.

[0050] The processing circuit may be configured to estimate the primary AOA of the first directional electromagnetic signal by calculating

[0051]

[0052]

[0053]

[0054] where Y is the estimated combined channel, and is the selected search angle b * The collection of angles in the surrounding neighborhood.

[0055] The processing circuit may be configured to select the selected search angle b according to the following formula * :

[0056]

[0057] in,

[0058]

[0059] The processing circuitry may be configured to select the selected search angle b based on an estimated main angle of arrival of a third directional electromagnetic signal received in a previous beam scanning period. * .

[0060] The processing circuit may be configured to calculate the value of the selected search angle b by the following formula: * The set of angles in the surrounding neighborhood

[0061]

[0062] Among them, N will The number of angles in is controlled to be 2N+1, and where Δ is Angular resolution of the angles in .

[0063] The number N of antenna elements in the antenna array R may be an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and wherein the one or more remaining angles of arrival It can be calculated according to the following formula:

[0064]

[0065] in, is the estimated principal angle of arrival of the first directional electromagnetic signal.

[0066] The number N of antenna elements in the antenna array R may not be an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and wherein the one or more remaining angles of arrival are selected from the angle constraint set was selected, among which,

[0067]

[0068] The processing circuit may be configured to determine the beamforming vector for data reception of a second directional electromagnetic signal by selecting the beamforming vector for data reception from the updated beamforming codebook without performing channel estimation.

[0069] Determining a beamforming vector for data reception of the second directional electromagnetic signal may include explicitly calculating the beamforming vector based on a channel estimate for the second directional electromagnetic signal and based on the updated beamforming codebook. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention.

[0071] Figure 1 is a block diagram of a beamforming wireless communication system according to one embodiment of the present disclosure.

[0072] Figure 2A、 Figure 2B and Figure 2C It is a schematic diagram for determining the angle of arrival of an electromagnetic signal.

[0073] Figure 3 is a block diagram of a beamforming codebook updater according to one embodiment of the present disclosure.

[0074] Figure 4 is a flow chart depicting a method 400 for updating a beamforming codebook for a next beam scan according to one embodiment of the present disclosure.

[0075] Figure 5 is a flowchart of a method for calculating the main angle of arrival (AoA) according to one embodiment of the present disclosure.

[0076] Figure 6 is a flowchart of a method for updating a codebook and receiving a signal according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0077] In the following detailed description, only certain exemplary embodiments of the present invention are shown and described by way of illustration. As those skilled in the art will recognize, the invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0078] In a hybrid beamforming wireless communication system, a mobile station (MS) (also referred to as a user equipment (UE)) or a base station (BS) periodically performs beam scanning to prevent poor link budget in order to improve performance (e.g., signal-to-noise ratio). Various aspects of the embodiments of the present disclosure will be described in the context of beam scanning at the UE, where the UE will be considered a receiver (Rx). However, the embodiments of the present disclosure are not limited thereto and may also be applied to base stations. When performing beam scanning measurements, the UE selects different beamforming vectors from a beamforming codebook W, where the beamforming vectors are used to combine with signals from different antennas attached to the UE (e.g., different antenna elements of an antenna array). Based on the beam scanning measurements, the UE determines a beamforming vector for data reception. Methods for determining a beamforming vector include: selecting a beamforming vector for data reception from a predefined beamforming codebook without performing channel estimation; and explicitly calculating a beamforming vector for data reception based on channel estimation. In both methods, the quality of the beamforming codebook W is an important factor in the quality of the determined beamforming vector. Therefore, aspects of the embodiments of the present disclosure are directed to systems and methods for updating a beamforming codebook W based on beam scanning measurements to improve system performance.

[0079] Figure 1 FIG is a block diagram of a beamforming wireless communication system according to an embodiment of the present disclosure. Figure 1 In the illustrated embodiment, a mobile station (MS) or user equipment (UE) 100 is in communication with a base station (BS) 200, where the base station 200 is transmitting a directional signal 30 (e.g., a directional electromagnetic signal) to the mobile station 100. The mobile station 100 includes an antenna array 120 comprising a plurality of antenna elements. Similarly, the base station 200 includes an antenna array 220 also comprising a plurality of antenna elements. Figure 1 In the illustrated embodiment, the antenna array 120 of the mobile station 100 and the antenna array 220 of the base station 200 are linear arrays, but the embodiments of the present disclosure are not limited thereto and are also applicable to antenna arrays of different shapes, such as planar arrays. The base station 200 can control the direction in which the antenna array 220 transmits the directional signal 30 by controlling the phase shift or time delay between the different elements providing the signal to the antenna array. Similarly, the mobile station 100 can control the direction in which the antenna array 120 receives the signal.

[0080] exist Figure 1 In the arrangement shown, the directional signal 30 arrives at the mobile station 100 at an angle θ relative to the antenna array 120. For ease of discussion, it will be assumed that the direction perpendicular to the antenna array is at an angle of zero (0), and that the antenna array 120 is capable of receiving signals over 360° (or 2π radians), so the angle θ may range from, for example, -180° to +180°, or in radians, (-π, π). Equivalently, the angle of arrival θ may be expressed as being within the range of 0° to 360° or 0 radians to 2π radians.

[0081] like Figure 1As shown, mobile station 100 includes a radio transceiver 10, which includes various components for recovering data encoded in a received directional signal 30. (Radio transceiver 10 may also include components for transmitting radio signals. Although the discussion herein focuses on the receive side of radio transceiver 10, embodiments of the present disclosure are not limited to radio receivers. For example, aspects of embodiments of the present disclosure may be applied to updating a beamforming codebook when performing beam scanning at a base station configured to transmit data.) Received directional signal 30 may be provided to a receive filter 12 (e.g., a bandpass filter), and the filtered signal may be provided to a detector 14 and a channel estimator 16. Channel estimator 16 may generate channel state information (CSI) that is used to control detector 14 and other components of radio transceiver 10 to adapt to changing conditions in the environment. These changing conditions in the environment may include the angle of arrival (AoA) θ of directional signal 30 received at antenna array 120 of mobile station 100. Some of the parameters provided from the channel estimator 16 to the detector 14 include parameters based on the currently estimated angle of arrival (AoA) of the received directional signal 30. The channel estimator 16 may provide these parameters based on the beamforming codebook W. According to some embodiments of the present disclosure, the channel estimator 16 is in communication with or includes a beamforming codebook updater 140, wherein the beamforming codebook updater 140 is configured to update the beamforming codebook between beam sweep periods, as discussed in more detail below.

[0082] The output of the channel estimator 16 is provided to the detector 14, which performs symbol detection using the channel state information. The decoder 18 may be configured to receive the detected symbols from the detector 14 and decode the detected symbols into data (such as a digital bit stream) for use by applications in the radio transceiver 10 (such as voice calls, data packets, etc.). In various embodiments of the present disclosure, components of the radio transceiver 10 (such as the filter 12, the detector 14, the channel estimator 16, the codebook updater 140, and the decoder 18) may be implemented in one or more processing circuits of a digital radio (e.g., a radio baseband processor (BP or BPP), a central processing unit (CPU), a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC)), wherein various portions of various blocks may be implemented in the same circuit (e.g., on the same die or in the same package) or in different circuits (e.g., on different dies connected by a communication bus or in different packages connected by a communication bus).

[0083] As described above, in a hybrid beamforming system, a radio receiver or radio transceiver may include an antenna array (e.g., antenna array 120) that can be steered to receive directional signals from any direction within a range of possible steering angles. In some cases, the antenna array is electronically steered using, for example, phase shifts or time delays between antenna elements (or receiving antennas) of the antenna array. A specific parameter corresponding to a given direction may be represented as a beamforming vector w. A beamforming codebook W may include two or more different beamforming vectors w. For example, a codebook W having M different beamforming vectors may be represented as:

[0084]

[0085] Among them, N R denotes the number of antenna elements (or receive antennas) per radio frequency (RF) chain, and assumes that N R >M.

[0086] Figure 2A 、 2B 2C is a schematic diagram for determining the arrival angle of the signal. Figure 2A 、 Figure 2B and Figure 2C In the illustrated embodiment, the antenna elements of the antenna array 120 are arranged in a linear array and the antenna elements are evenly spaced apart by a distance d. Figure 2A As shown, the directional signal 30 arrives at an angle θ measured relative to a direction perpendicular to the antenna array 120. As described above, it is assumed that the antenna array 120 is capable of receiving signals received at angles from -π to π. Figure 2A The codebook W is shown with two beamforming vectors w (M=2). The range -π to π is divided into a first sector 201 corresponding to an angle of arrival in the range (-π, 0) and a second sector 202 corresponding to an angle of arrival in the range (0, π). The first sector 201 corresponds to a first beamforming vector 211 along an angle of -π / 2, and the second sector 202 corresponds to a second beamforming vector 212 along an angle of π / 2.

[0087] The actual channel H on K different subcarriers can be expressed as:

[0088]

[0089] The combined signal Z can be modeled as:

[0090] Z=W(HP+V) (3)

[0091] Where P = diag(p1, ..., p K ) represents the beam scanning reference symbol in the directional signal 30 transmitted during the current (tth) beam scanning period, and represents the channel noise.

[0092] Based on this model of the combined signal Z, the channel estimator 16 estimates the combined channel H for the t-th beam scanning period. c =WH, where is represented by the H c , and where Y t is modeled as:

[0093] Y t =H c +N t , where H c =W t H t , (4) in, is the current beamforming codebook for the t-th beam scanning period, is an unknown channel, and N t represents the estimation error of the combined channel during the t-th beam scanning period and is expressed as:

[0094]

[0095] After performing the beam scanning, the best beamforming vector may be selected among the scanned beamforming vectors w to improve the analog beamforming gain (e.g., improve the performance of the detector 14 in detecting symbols in the received directional signal 30). Figure 2A In the example shown, the channel estimator can select between first beamforming vector 211 and second beamforming vector 212. Because the arrival angle θ of directional signal 30 is in second sector 202 and second beamforming vector 212 is closer to the actual arrival angle θ of directional signal 30, the channel estimator can select second beamforming vector 212 as the optimal beamforming vector. Alternatively, given measurements obtained from the beam scanning process, a simulated channel can be estimated so that a beamforming vector for data reception (e.g., during a data reception period or a data transmission period between beam scanning periods) can be derived to further improve system performance. In both cases, the selection of beamforming codebook W is a major factor in the system performance of the radio receiver.

[0096] Figure 2BAnother example is provided in which the codebook W includes three beamforming vectors (M=3). In more detail, the first sector 221 may correspond to an angle of arrival from -π to -π / 3 and corresponds to a first beamforming vector 231 at an angle of -2π / 3, the second sector 222 may correspond to an angle of arrival from -π / 3 to +π / 3 and corresponds to a second beamforming vector 232 at an angle of 0 (or boresight), and the third sector 223 may correspond to an angle of arrival from +π / 3 to +π and corresponds to a third beamforming vector 233 at an angle of +2π / 3.

[0097] exist Figure 2B In the arrangement shown, the channel estimator 16 may determine that the second beamforming vector 232 is the optimal beamforming vector and provide the parameters of the second beamforming vector 232 to the detector 14 for use in decoding the received directional signal 30. Figure 2B As shown, the second beamforming vector 232 is not perfectly aligned with the angle of arrival of the received directional signal 30, and if the beamforming vector is selected to more closely match the angle of arrival of the received signal 30, the performance of the radio transceiver 10 in decoding the signal will be improved.

[0098] Therefore, aspects of the embodiments of the present disclosure relate to and based on the beamforming codebook for the current (t) beam scanning period Calculate the updated beamforming codebook W for the next (t+1) beam scanning period t+1 , improving the hybrid beamforming gain. (This can be equivalently expressed as updating the previous beamforming codebook W during the previous beam scanning period t-1 t-1 To calculate the updated beamforming codebook (or current beamforming codebook) W for the current period t t .

[0099] Figure 2C FIG shows the case of updating the beamforming codebook. Figure 2C As shown, after updating the beamforming codebook, the directions of the updated beamforming vectors 231', 232' and 233' are different from Figure 2B The directions of beamforming vectors 231, 232, and 233 are shown. More specifically, the direction of the updated first beamforming vector 231' is aligned with the angle of arrival of the directional signal 30, and the endpoint of the corresponding third sector 221' is also updated. The updated second beamforming vector 232' and third beamforming vector 233' are also updated to point in the new directions. Systems and methods for calculating an updated beamforming codebook according to embodiments of the present disclosure are described in more detail below.

[0100] Figure 3FIG. 1 is a block diagram of the beamforming codebook updater 140 according to one embodiment of the present disclosure. Figure 3 As shown, in one embodiment, the codebook updater 140 includes a primary angle of arrival (AoA) estimator 142 , a residual angle of arrival (AoA) calculator 144 , and a codebook constructor 146 . Figure 4 is a flow chart depicting a method 400 for updating a beamforming codebook according to one embodiment of the present disclosure.

[0101] refer to Figure 3 and Figure 4 According to one embodiment of the present disclosure, the channel estimator 16 estimates the combined channel Y t Provided to the codebook updater 140. The codebook updater 140 may also receive the beamforming codebook W of the current beam scanning period t t As input, the codebook updater 140 may alternatively have a beamforming codebook already stored in memory (eg, from a previous calculation or upon initialization of the codebook updater 140).

[0102] Various aspects of the embodiments of the present disclosure relate to a method based on compressed sensing (CS or compressed sensing) for codebook updating under the assumption that the channel is sparse in the angular domain. As described above, given θ as the angle of arrival (AoA) of the directional signal 30 and d as the antenna spacing or antenna distance of the antenna elements of the uniform linear array, the antenna response vector can be written as:

[0103]

[0104] Where λ represents the wavelength, T represents the transposition operation, and without loss of generality, it is assumed that d = λ / 2 and x = πcosθ. It is expressed as a set of quantized values of the angle of arrival (AoA), where:

[0105]

[0106] In some embodiments of the present disclosure, the initial beamforming codebook (e.g., when the system is first started, before any updates to the beamforming codebook are performed) is a uniform discrete Fourier transform (DFT) codebook. In some embodiments, the initial beamforming codebook is a partial identification codebook. In some embodiments, the initial beamforming codebook is the codebook given below:

[0107] W=[u M 0] (8)

[0108] Among them, U M is a special unitary matrix. As described in more detail below, when U M When the full-size DFT matrix is used, the codebook updater 140 can update the codebook from UM M angles are extracted to estimate the main AoA.

[0109] In operation 410, the main AoA estimator 142 of the codebook updater 140 generates an AoA estimator based on a given estimated combined channel Y and a current beamforming codebook W. t To estimate the main AoA

[0110] In estimating the main AoA Thereafter, in operation 450, the residual AoA calculator 144 of the codebook updater 140 calculates the residual AoA of the updated codebook. And in operation 490, the codebook constructor 146 of the codebook updater 140 generates a codebook based on the calculated primary AoA and the remaining AoA To construct the updated beamforming codebook W t+1 .

[0111] The calculation of the primary AoA by the primary AoA estimator 142 in operation 410 will be described in more detail below for two different cases. and the remaining M-1 AoAs are calculated by the remaining AoA calculator 144 in operation 450. Details: The case where the beamforming codebook W contains exactly two beamforming vectors (M=2) (e.g., Figure 2A As shown); and the case where the beamforming codebook W includes more than two beamforming vectors (M>2) (equivalently, three or more beamforming vectors M≥3, for example, the case where M=3, as shown in Figure 2B and Figure 2C shown).

[0112] When the beamforming codebook W includes exactly two beamforming vectors (M=2) and the number of antenna elements N in the receive antenna array 120 is R If is an even number, the beamforming codebook W can be written as:

[0113]

[0114]

[0115] Among them, C i is some constant, then the primary AoA estimator 142 estimates the primary AoA in operation 410 according to the closed-form solution given below

[0116]

[0117]

[0118]

[0119] in, and is the estimated simulated channel corresponding to the first two antenna elements (eg, two antenna elements of an antenna array).

[0120] In this embodiment, the remaining AoA calculator 144 calculates the remaining AoA in operation 450 based on The only other AoA (Since M=2, therefore M-1=1) is calculated to point in the opposite direction of the main AoA.

[0121] Therefore, in operation 490, the codebook constructor 146 updates the beamforming codebook W t+1 The structure is:

[0122]

[0123] Updated beamforming codebook W t+1 is a uniform discrete Fourier transform (DFT) codebook. If N R is an even number, then W t+1 The conditions of equations (9) and (10) above are satisfied. Therefore, in the case of M=2, during each beam sweep period, the main AoA of the updated beamforming codebook can be derived using the closed-form solution according to equations (11), (12), and (13). and the remaining AoA (another AoA ).

[0124] In the case where the beamforming codebook includes more than two beamforming vectors (M>2), aspects of embodiments of the present disclosure are directed to reducing the complexity of the primary AoA estimator 142 searching for the primary AoA in operation 410 by searching only in a specific set of angles. Figure 5 is a flowchart of a method for calculating the main angle of arrival (AoA) according to one embodiment of the present disclosure.

[0125] Assume that each beamforming vector w in the beamforming codebook W is a discrete Fourier transform (DFT) vector, and each beamforming vector w corresponds to an angle b1, ..., b M , then the beamforming codebook W can be expressed as:

[0126]

[0127] In other words, the main AoA estimator selects the angle with the maximum received signal power from the current beamforming codebook W by selecting the angle with the maximum received signal power (e.g., maximizing the following expression): t Angles b1,...,b M Select the primary AoA b * :

[0128]

[0129] Expressed in the formula, the main AoA of the channel is It is estimated according to the following formula:

[0130]

[0131] where H represents the conjugate transpose, and where is the selected search angle b * The collection of angles in the surrounding neighborhood.

[0132] In some embodiments of the present invention, Refers to N quantized values uniformly sampled between −π and π (eg, the full range of possible values). This approach may be beneficial when there is no a priori knowledge about the possible angles of arrival of the received directional signal 30 .

[0133] In some embodiments, aspects of the disclosed embodiments involve the primary AoA estimator 142 performing a search at an angle b. * The main AoA is calculated from the neighborhood of potential angles sampled around Instead of searching between N quantized values uniformly sampled between –π and π, the search angle b * From b1, ..., b M According to some embodiments, at operation 412, the master AoA estimator 142 selects b1, ..., b M Select search angle b * In some embodiments, b * It is calculated according to the following formula:

[0134]

[0135]

[0136] According to some embodiments of the present disclosure, at a given selected search angle b * In the case of * The set of possible search angles in the neighborhood of is given by:

[0137]

[0138] In the above expression, nine possible search angles are calculated with an angular resolution of π / 8. However, embodiments of the present disclosure are not limited thereto and may include other numbers of sampling points, such as 17 points sampled with an angular resolution of π / 16 or 13 points sampled with an angular resolution of π / 12.

[0139] More generally, for the primary AoA estimate of M>2, given the chosen angle b * , when estimating the main AoA When , the possible search angles in the neighborhood can be calculated More specifically, the complexity that can be tolerated by the hardware constraints of the codebook updater 140 and the angle b selected are * The master AoA estimator 142 can determine the confidence level by selecting the angular resolution Δ and the set of possible search angles The set of possible search angles is dynamically adjusted by using an appropriate value of the number of angles 2N+1 in

[0140]

[0141] For example, if complexity is not an issue (e.g., the codebook updater has sufficient processing power to perform the calculation within the allocated time window (e.g., before the next (t+1) beam sweep period)), the main AoA estimator 142 may use a large value of N and a small value of Δ. * The confidence level is high (for example, the angle b is selected * If the confidence that the AoA is close to the actual angle of arrival is high), then given the complexity level, a small value of Δ may be chosen to have a finer angular resolution (e.g., potentially producing an estimated primary AoA that is closer to the actual AoA of the received directional signal 30).

[0142] In operation 416, the main AoA estimator 142 then calculates the AoA from the neighborhood of the selected search angle b* according to the following equation: Identify the primary AoA from the angles in

[0143]

[0144] In other words, the main AoA estimator 142 calculates the selected search angle b * Surrounding sampling points The correlation of the 9 points (e.g., the 9 points in the above expression) is calculated and the angle with the largest correlation is selected as the estimated primary AoA. In some embodiments, where each row in the beamforming codebook W is not a DFT vector, the correlation of several AoAs is calculated, and b is selected based on the highest correlation AoA among the several AoAs. *.

[0145] In addition, in some embodiments of the present disclosure, if the primary AoA of the actual channel If the search angle b is changed slowly between two beam scanning periods (for example, because the mobile station is relatively stationary or dormant), then in the t-th beam scanning period, the search angle b is selected to be * will be equal to or close to the estimated primary AoA from the previous beam sweep period (t-1) Therefore, in some embodiments of the present disclosure, for t>1, instead of calculating Instead, the primary AoA from the previous beam sweep period is used in operation 412 Alternative search angles Among them, during the current beam scanning period, the search angle However, for the first beam sweep period (t=1), since there is no information available about the channel primary AoA, the primary AoA estimator 142 may calculate the selected search angle (Note that the approximations discussed above apply to the number of beamforming vectors M and the number of receive antennas N. R Any value of .)

[0146] In some embodiments of the present disclosure, for the period after the initial period (t>1), the primary AoA The estimation of is further simplified. In particular, it is expressed as:

[0147]

[0148] as well as

[0149]

[0150]

[0151] Then, in some embodiments, the main AoA for the current beam scanning period t is calculated according to the following formula:

[0152]

[0153] In other words, in some embodiments of the present disclosure, the main AoA estimator 142 estimates Only the first two beam scan measurements are considered when y 1t and y 2t (However, when recovering the channel using detector 14, the current beamforming codebook W is taken into account. t All beam vectors in . )

[0154] Return to reference Figure 3 and Figure 4 , in operation 450 , for the case of M>2, the remaining AoA calculator 144 calculates the remaining (M−1) AoAs (or beamforming vectors) of the updated codebook W.

[0155] The number N of antenna elements in the antenna array 120 R In an embodiment where σ is an integer multiple of the number M of beamforming vectors in the beamforming codebook W, the residual AoA calculator calculates the residual AoA according to the following formula in operation 450:

[0156]

[0157] The number N of antenna elements in the antenna array 120 R In embodiments where the number of beamforming vectors M in the beamforming codebook W is not an integer multiple, the remaining AoA calculator in operation 450 selects from an angularly constrained set of possible AoAs spaced around a range of 360° or 2π. Calculate the residual AoA, where:

[0158]

[0159] In more detail, in some embodiments, the eigenvalues are obtained from the eigenvalues by an iterative process such as simultaneous orthogonal matching pursuit (SOMP). Calculate the remaining AoA.

[0160] In some embodiments, such as where the residual AoA calculator 144 is computationally constrained (e.g., using an iterative algorithm may be impractical within the system's time and / or energy budget), the residual AoA calculator 144 generates an orthogonally updated codebook from The remaining AoAs are selected from , as described in more detail below.

[0161] As an example, in the case of M=3, according to one embodiment, given the estimated primary AoA Perform the selection for the remaining AoAs by selecting:

[0162]

[0163]

[0164] When M is not 3, we can select The remaining AoAs are arbitrarily selected from to form an orthogonal beamforming codebook.

[0165] According to another embodiment of the present disclosure, there is an even number N in the receiving antenna array 120. R Given the estimated primary AoA An arbitrary selection of the remaining AoAs is performed by selecting:

[0166]

[0167]

[0168] When M is not 3, we can select The remaining AoAs are arbitrarily selected to form an orthogonal beamforming codebook.

[0169] Given the beamforming vectors or AoAs estimated by the main AoA estimator 142 and the residual AoA calculator 144 as discussed above, the codebook constructor 146 constructs an updated beamforming codebook W according to the following equation: t+1 :

[0170]

[0171] Figure 6 FIG. 1 is a flow chart of a method for updating a codebook and receiving a signal according to an embodiment of the present disclosure. Figure 6 In the illustrated embodiment, operations for receiving a beam scanning signal during the (t-1)th cycle or a previous cycle, operations for calculating an updated codebook for the next cycle (e.g., the tth cycle or the "current cycle"), and operations for determining a beamforming vector for a received data signal for the current cycle (tth cycle) using the updated codebook are described.

[0172] like Figure 6 As shown, in operation 601, during the (t-1)th cycle, a radio transceiver (e.g., the radio transceiver 10 of the mobile station 100) receives the (t-1)th directional electromagnetic beam scanning signal at the antenna array (e.g., the antenna array 120) during the beam scanning period (e.g., the (t-1)th beam scanning period of the (t-1)th cycle), and calculates an estimated combined channel Y based on the received beam scanning signal (e.g., using the channel estimator 16). t-1 In operation 603, the radio transceiver uses the above method such as Figure 4 and Figure 5 The system and method described in the illustrated embodiment is based on the estimated combined channel Y t-1 and the beamforming codebook W for the (t-1)th period t-1 To calculate the updated beamforming codebook W t In a manner similar to operation 603, the updated current beamforming codebook W for the current period t may then be used in operation 613. t To calculate the next beamforming codebook W for the next period (t+1) t+1 , as described in more detail below.

[0173] like Figure 6 As shown, in operation 605, during the (t-1)th data reception period, the radio transceiver may perform beamforming based on the beamforming codebook W calculated in an earlier cycle (eg, the (t-2)th cycle). t-1 To determine the beamforming vector w for a directional electromagnetic data signal received at the same antenna array (e.g., antenna array 120) t-1 The method for determining the beamforming vector will be described in more detail below with respect to operation 615. At operation 607, using the determined beamforming vector (e.g., as a channel state information parameter), the detector 14 detects data symbols in the received directional electromagnetic data signal, and the decoder 18 may decode the data in the received data symbols.

[0174] exist Figure 6 In the illustrated embodiment, computing the previous estimated combined channel 601, computing the updated current codebook 603, determining the previous beamforming vector 605, and detecting the previous data symbol 607 are all performed during the previous cycle or the (t-1)th cycle (or the first cycle). Figure 6 Also depicted are operations 611 , 613 , 615 , and 617 performed during the t-th cycle (or second cycle) following the current cycle or the previous cycle (eg, immediately following the (t−1)-th cycle).

[0175] refer to Figure 6 , at operation 611, during the tth cycle or the current cycle, the radio transceiver receives the tth directional electromagnetic beam scanning signal at the antenna array (e.g., the same antenna array 120 used during the (t-1)th cycle) during another beam scanning period (e.g., the tth beam scanning period of the tth cycle), and calculates the estimated combined channel Y for the current cycle based on the received beam scanning signal t (For example, using the channel estimator 16). In operation 613, the radio transceiver uses the above-mentioned Figure 4 and Figure 5 The system and method described in the illustrated embodiment is based on the current estimated combined channel and the current beamforming codebook W for the tth period. t , calculate the updated beamforming codebook W for the next cycle (e.g., the (t+1)th cycle) t+1 .exist Figure 6 In the embodiment shown, the current beamforming codebook W used in operations 613 and 615 is t is the codebook calculated in operation 603 during the previous (t-1)th period.

[0176] In operation 615, during the t-th data reception period, the radio transceiver may perform beamforming based on the current beamforming codebook W calculated in an earlier cycle (eg, calculated during the previous cycle or the (t-1)-th cycle). t To determine a beamforming vector for a directional electromagnetic data signal (or tth data signal) received at the same antenna array (eg, antenna array 120).

[0177] The method for determining a beamforming vector for a received directional electromagnetic data signal comprises determining, without performing channel estimation, from a current beamforming codebook W for a current period t t and explicitly calculating the beamforming vector for data reception based on a recovered simulated channel of the directional electromagnetic data signal, wherein the simulated channel may be based on a current beamforming codebook W for the current period t. t and the current combined channel Y t The estimate of is restored. t In the embodiment where the beamforming vectors are explicitly calculated based on the recovered simulated channel, the updated beamforming codebook W t It can be used with various channel recovery techniques, such as least squares and / or compressed sensing based algorithms.

[0178] In operation 617 , using the determined beamforming vector for the current period t (eg, as a channel state information parameter), the detector 14 detects data symbols in the received tth directional electromagnetic data signal, and the decoder 18 may decode data in the received data symbols.

[0179] By updating the beamforming codebook based on the beamforming signal from the most recent beam sweep period (e.g., the immediately previous beam sweep period), whether by updating the beamforming codebook W from the beamforming codebook W without performing channel estimation t+1 The beamforming vector for data reception is selected based on the channel estimation and the beamforming codebook W t+1 By explicitly calculating beamforming vectors for data reception, aspects of the disclosed embodiments prevent poor link budgets by improving the quality (eg, signal-to-noise ratio) of reception and decoding of received directional electromagnetic data signals.

[0180] For clarity, each cycle will typically include both a beam scanning period and a data reception period, but embodiments of the present disclosure are not limited thereto. Figure 6 In the illustrated embodiment, the previous or (t-1)th cycle may include a beam sweeping period but may not include a data reception period, and the current or tth cycle may include a data reception period and may not include a beam sweeping period. Figure 6Operations 605, 607, 611, and 613 are shown using dashed lines to indicate that they are optional. Figure 6 Although the updated codebook for the next cycle is calculated before the beamforming vector for the data signal of the current cycle is determined, the embodiments of the present disclosure are not limited thereto. For example, in some embodiments, the updated codebook for the next cycle is calculated after the beamforming vector for the data signal of the current cycle is determined.

[0181] Thus, various aspects of the present disclosure relate to systems and methods for updating a beamforming codebook by aligning its beamforming vectors with an estimated primary angle of arrival of a received signal to improve analog beamforming gain. Some aspects of the present disclosure relate to systems and methods for calculating an estimated primary angle of arrival. Some aspects of the present disclosure relate to calculating residual angles of arrival for residual beamforming vectors of a codebook based on the estimated primary angle of arrival.

[0182] Although aspects of the embodiments of the present disclosure are described above with respect to linear antenna arrays, the embodiments of the present disclosure are not limited thereto and are applicable to antenna arrays having different shapes. For example, in the case of a planar antenna array, the antenna elements may be spaced apart along two dimensions. In such an embodiment, the received directional signal may be considered to have an angle of arrival (AoA) and a zenith angle of arrival (ZoA). Similarly, each beamforming vector of the codebook may also have an AoA and a ZoA. In Figure 2A 、 Figure 2B and Figure 2C In the illustrated embodiment, each beamforming vector is associated with a sector or angular range. In a similar manner, each beamforming vector in the case of a planar array can be associated with a solid angle of a potential combination of AoA and ZoA. As will be appreciated by those skilled in the art, the methods used to calculate the estimated primary AoA and ZoA and the codebook can be adapted for use with planar arrays. For example, assuming a planar array with N x Row and N y If the antenna elements are arranged in a rectangular grid of columns, and under the assumption that the antenna elements are spaced apart by a distance of half the wavelength of the carrier, then the antenna response vector a(θ, φ) can be written as:

[0183]

[0184] in, represents the Kronecker product, and

[0185]

[0186] Therein, the calculation of the updated beamforming codebook W can be performed in a manner substantially similar to that described above, but using the antenna response vector a(θ, φ) for a planar array instead of the antenna response vector a(θ) for a linear array.

[0187] The term "processing circuit" is used herein to refer to any combination of hardware, firmware, and software for processing data or digital signals. The processing circuit hardware may include, for example, a radio baseband processor (BP or BBP), an application-specific integrated circuit (ASIC), a general-purpose or dedicated central processing unit (CPU), a digital signal processor (DSP), a graphics processing unit (GPU), a programmable logic device such as a field programmable gate array (FPGA). In a processing circuit, as used herein, each function is performed by hardware that is constructed (i.e., hardwired) to perform the function, or by more general hardware (such as a CPU) that is constructed to execute instructions stored in a non-transitory storage medium. The processing circuit may be manufactured on a single printed circuit board (PCB) or distributed on several interconnected PCBs. The processing circuit may include other processing circuits; for example, the processing circuit may include two processing circuits, an FPGA, and a CPU, interconnected on a PCB.

[0188] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, a first element, component, region, layer, or part discussed herein may be referred to as a second element, component, region, layer, or part without departing from the spirit and scope of the present disclosure.

[0189] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the terms "substantially," "approximately," and similar terms are used as terms of approximation rather than terms of degree, and are intended to take into account the inherent deviations in measurements or calculations that one of ordinary skill in the art would recognize.

[0190] As used herein, the singular form is intended to also include the plural form, unless the context clearly states otherwise. It will be further understood that, when used in this specification, the terms "include" and / or "comprising" specify the existence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. As used herein, the term "and / or" includes any and all combinations of one or more items in the associated listed items. Statements such as "at least one of..." modify the entire element list when following the element list, without modifying the individual elements of the list. In addition, when describing an embodiment of the present disclosure, "may" is used to refer to "one or more embodiments of the present disclosure." In addition, the term "exemplary" is intended to indicate an example or explanation. As used herein, the terms "use," "being in use," and "being used" may be considered to be synonymous with the terms "utilize," "being utilized," and "being utilized," respectively.

[0191] It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “adjacent to” another element or layer, it can be directly on, connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “immediately adjacent to” another element or layer, there are no intervening elements or layers present.

[0192] Any numerical range described herein is intended to include all subranges of the same numerical precision contained within the range. For example, a range of "1.0 to 10.0" is intended to include all subranges between (and including) the recited minimum value of 1.0 and the recited maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit recited herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit recited in this specification is intended to include all higher numerical limits contained therein.

[0193] While the invention has been described with reference to the specific exemplary embodiments, it will be understood that the invention is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents.

Claims

1. A method for updating a beamforming codebook, comprising: receiving, at an antenna array of a wireless communication device during a previous cycle, a first directional electromagnetic signal including a beam scanning reference symbol for a previous beam scanning period; calculating, by processing circuitry of the wireless communication device, an estimated combined channel based on the received first directional electromagnetic signal; estimating, by the processing circuitry, a dominant angle of arrival of a first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different angles of arrival; as well as calculating, by the processing circuitry, one or more residual angles of arrival spaced apart from the estimated primary angle of arrival; constructing, by the processing circuitry, an updated beamforming codebook based on the estimated primary angle of arrival and the one or more residual angles of arrival; receiving a second directional electromagnetic signal comprising a data symbol at the antenna array during a current period; determining a beamforming vector for data reception of a second directional electromagnetic signal based on the updated beamforming codebook; as well as The data symbols are detected in a second directional electromagnetic signal by the processing circuit based on the determined beamforming vector.

2. The method according to claim 1, wherein The updated beamforming codebook consists of two beamforming vectors, The main arrival angle of the first directional electromagnetic signal is estimated The steps include calculating the following formula: in, as well as where Y is the estimated combined channel, and and are the estimated simulated channels corresponding to the two antenna elements of the antenna array, wherein the one or more remaining angles of arrival correspond to a beamforming vector, wherein the antenna array has an even number of antenna elements, and wherein the residual angle of arrival according to is calculated, and The updated beamforming codebook W t It is calculated according to the following formula: , where a represents the antenna response vector.

3. The method according to claim 1, wherein The updated beamforming codebook includes three or more beamforming vectors.

4. The method according to claim 3, wherein: Estimating the main angle of arrival of the first directional electromagnetic signal The steps include calculating the following formula: where Y is the estimated combined channel, and is the selected search angle b * The set of angles in the surrounding neighborhood, represents the quantized value of the i-th arrival angle, x represents the possible search angle, W represents the beamforming codebook, M represents the number of beamforming vectors in the beamforming codebook, and N R Indicates the number of antenna elements.

5. The method according to claim 4, wherein Selected search angle b * is selected according to the following formula: in, ， Among them, y m represents the mth estimated channel.

6. The method according to claim 4, wherein: Selected search angle b * is selected based on an estimated main angle of arrival of a third directional electromagnetic signal received in a previous beam scanning period.

7. The method according to claim 4, wherein: In the selected search angle b * The set of angles in the surrounding neighborhood It is calculated by the following formula: Among them, N will The number of angles in is controlled to be 2N+1, and where Δ is Angular resolution of angles in .

8. The method according to claim 3, wherein: The number N of antenna elements in the antenna array R is an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and Wherein, the one or more remaining arrival angles It is calculated according to the following formula: in, is the estimated principal angle of arrival of the first directional electromagnetic signal.

9. The method according to claim 3, wherein: The number N of antenna elements in the antenna array R is not an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and Wherein, the one or more remaining arrival angles are from the angle constraint set was selected, among which, 10. The method according to claim 1, wherein The step of determining a beamforming vector for data reception of the second directional electromagnetic signal comprises selecting the beamforming vector for data reception from the updated beamforming codebook without performing channel estimation.

11. The method according to claim 1, wherein The step of determining a beamforming vector for data reception of the second directional electromagnetic signal comprises explicitly calculating the beamforming vector based on a channel estimate of the second directional electromagnetic signal and based on the updated beamforming codebook.

12. A wireless communication apparatus configured to update a beamforming codebook, the wireless communication apparatus comprising: Antenna arrays; a processing circuit configured to receive a signal from the antenna array and configured to: receiving at the antenna array a first directional electromagnetic signal including a beam scanning reference symbol for a previous beam scanning period during a previous cycle; calculating an estimated combined channel based on the received first directional electromagnetic signal; estimating a dominant angle of arrival of the first directional electromagnetic signal based on the estimated combined channel and a previous beamforming codebook including two or more beamforming vectors corresponding to different angles of arrival; as well as calculating one or more residual angles of arrival spaced apart from the estimated main angle of arrival; constructing an updated beamforming codebook based on the estimated primary angle of arrival and the one or more residual angles of arrival; receiving a second directional electromagnetic signal comprising a data symbol at the antenna array during a current period; determining a beamforming vector for data reception of a second directional electromagnetic signal based on the updated beamforming codebook; as well as The data symbol is detected in the second directional electromagnetic signal based on the determined beamforming vector.

13. The wireless communication device according to claim 12, wherein: The updated beamforming codebook consists of two beamforming vectors, The processing circuit is configured to estimate the main arrival angle of the first directional electromagnetic signal by calculating the following formula: in, as well as where Y is the estimated combined channel, and and are the estimated simulated channels corresponding to the two antenna elements of the antenna array, wherein the one or more remaining angles of arrival correspond to a beamforming vector, wherein the antenna array has an even number of antenna elements, and wherein the residual angle of arrival according to is calculated, and The updated beamforming codebook W t It is calculated according to the following formula: ， Where a represents the antenna response vector.

14. The wireless communication device according to claim 12, wherein: The updated beamforming codebook includes three or more beamforming vectors.

15. The wireless communication device according to claim 14, wherein: The processing circuit is configured to estimate the main arrival angle of the first directional electromagnetic signal by calculating the following formula where Y is the estimated combined channel, and is the selected search angle b * The set of angles in the surrounding neighborhood, represents the quantized value of the i-th arrival angle, x represents the possible search angle, W represents the beamforming codebook, M represents the number of beamforming vectors in the beamforming codebook, and N R Indicates the number of antenna elements. The wireless communication device according to claim 15 , wherein: The processing circuit is configured to select the selected search angle b according to the following formula * : in, ， Among them, y m represents the mth estimated channel.

17. The wireless communication device according to claim 15, wherein: The processing circuit is configured to select the selected search angle b based on an estimated main angle of arrival of a third directional electromagnetic signal received in a previous beam scanning period. * .

18. The wireless communication device according to claim 15, wherein: The processing circuit is configured to calculate the selected search angle b by the following formula * The set of angles in the surrounding neighborhood Among them, N will The number of angles in is controlled to be 2N+1, and where Δ is Angular resolution of the angles in .

19. The wireless communication device according to claim 14, wherein: The number N of antenna elements in the antenna array R is an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and Wherein, the one or more remaining arrival angles It is calculated according to the following formula: in, is the estimated principal angle of arrival of the first directional electromagnetic signal.

20. The wireless communication device according to claim 14, wherein The number N of antenna elements in the antenna array R is not an integer multiple of the number M of beamforming vectors in the updated beamforming codebook, and Wherein, the one or more remaining arrival angles are from the angle constraint set was selected, among which, 21. The wireless communication device according to claim 12, wherein: The processing circuit is configured to determine the beamforming vector for data reception of a second directional electromagnetic signal by selecting the beamforming vector for data reception from the updated beamforming codebook without performing channel estimation.

22. The wireless communication device according to claim 12, wherein: Determining a beamforming vector for data reception of the second directional electromagnetic signal includes explicitly calculating the beamforming vector based on a channel estimate of the second directional electromagnetic signal and based on the updated beamforming codebook.

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