Method for time, spatial separation and channel non-reciprocity correction of polarized beams and multiple-beam antenna apparatus using the same

Abstract

Disclosed are a method for time, spatial separation and channel non-reciprocity correction of polarized beams and a multiple-beam antenna apparatus using the same. According to an aspect of the present invention, the multiple-beam antenna apparatus has an array antenna including a transmission antenna unit for forming a plurality of transmission beams and a reception antenna unit for forming a plurality of reception beams. The multiple-beam antenna apparatus separates polarized beams in time and space using two kinds of orthogonal polarization different from each other and corrects channel non-reciprocity due to the time polarization separation.

Description

Technical Field

[0001] This invention relates to antenna devices that can be used in conventional cellular communication systems, and more specifically, to a method and an antenna device utilizing the same for separating polarized beams in time and space and correcting channel non-reciprocity caused by polarization separation. Background Technology

[0002] The content described in this section is merely for providing background information for this invention and does not constitute prior art.

[0003] In order to meet the increasing demand for wireless data traffic after the commercialization of 4G (fourth generation) communication systems, we are making every effort to develop improved 5G (fifth generation) communication systems or pre-5G communication systems.

[0004] Therefore, 5G communication systems or pre-5G communication systems are also called Beyond 4G Network communication systems or Post LTE (Long Term Evolution) systems.

[0005] To achieve higher data transmission rates, 5G communication systems are being considered for implementation in higher frequency (mmWave) bands (e.g., the 60GHz band). To reduce propagation path loss and increase transmission distance in ultra-high frequency bands, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antenna technologies are being discussed in 5G communication systems.

[0006] In addition, to improve the system network, technologies such as evolutionary small cell, advanced small cell, cloud radio access network (cloudRAN), ultra-dense network, device-to-device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation are being developed in 5G communication systems.

[0007] In addition, in 5G systems, FQAM (Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation) and SWSC (Sliding Window Superposition Coding) have been developed as Advanced Coding Modulation (ACM), and FBMC (Filter Bank Multi Carrier), NOMA (Non Orthogonal Multiple Access), and SCMA (Sparse Code Multiple Access) have been developed as advanced access technologies.

[0008] In 5G communication systems, beamforming methods are being used to improve signal gain in order to overcome the path loss caused by the characteristics of ultra-high frequency bands (such as mmWave). Summary of the Invention

[0009] (a) Technical problems to be solved

[0010] One aspect of the present invention aims to provide a method for separating polarized beams in time and space using two different orthogonal polarizations, and for correcting channel non-reciprocity caused by polarization separation, as well as a multi-beam antenna device using the same.

[0011] (II) Technical Solution

[0012] According to one aspect of the present invention, a method is provided that is performed in a multi-beam antenna device with two orthogonal polarizations. The multi-beam antenna device has an array antenna including transmitting antenna elements for forming multiple transmitting beams and receiving antenna elements for forming multiple receiving beams.

[0013] The method includes: generating multiple transmission polarization components from the transmission signals corresponding to a pair of transmission channels associated with each transmission beam; and outputting a pair of transmission polarization components corresponding to a first orthogonal polarization or a pair of transmission polarization components corresponding to a second orthogonal polarization among the multiple transmission polarization components for a pair of transmission channels associated with each transmission beam, so that spatially adjacent transmission beams have different orthogonal polarizations.

[0014] In one embodiment, the method further includes: generating a plurality of receiving polarization components based on the received signals corresponding to a pair of receiving channels associated with each receiving beam for channel non-reciprocity correction; and outputting a pair of receiving polarization components, among the plurality of receiving polarization components, corresponding to the orthogonal polarization of the transmitted beams formed in the same spatial direction, to a pair of receiving channels associated with each receiving beam. Optionally, the method further includes: generating a polarization conversion signal corresponding to the orthogonal polarization of the transmitted beams formed in the same spatial direction, based on the received signals corresponding to a pair of receiving channels associated with each receiving beam for channel non-reciprocity correction.

[0015] According to another aspect of the present invention, a multi-beam antenna device utilizing two orthogonal polarizations is provided. The antenna device includes: an array antenna comprising a transmitting antenna element for forming multiple transmitting beams and a receiving antenna element for forming multiple receiving beams; a transmitting polarization combining unit that generates multiple transmitting polarization components from transmitting signals corresponding to a pair of transmitting channels associated with each transmitting beam; and a transmitting polarization distributing unit that outputs a pair of transmitting polarization components corresponding to a first orthogonal polarization or a pair of transmitting polarization components corresponding to a second orthogonal polarization to a pair of transmitting channels associated with each transmitting beam, so that spatially adjacent transmitting beams have mutually different orthogonal polarizations.

[0016] In one embodiment, the antenna device further includes: a receiving polarization combining unit, which generates a plurality of receiving polarization components based on the received signals corresponding to a pair of receiving channels associated with each receiving beam in order to perform channel non-reciprocity correction; and a receiving polarization allocating unit, which outputs a pair of receiving polarization components corresponding to the orthogonal polarizations of the transmitted beams formed in the same spatial direction to a pair of receiving channels associated with each receiving beam. Optionally, the antenna device further includes: a polarization conversion unit, which generates a polarization conversion signal from the received signals corresponding to the pair of receiving channels associated with each receiving beam, the polarization conversion signal corresponding to the orthogonal polarizations of the transmitted beams formed in the same spatial direction by each receiving beam.

[0017] (III) Beneficial Effects

[0018] As described above, by employing an array antenna including a transmitting antenna element and a receiving antenna element, the antenna device according to the present invention does not require switching operations that could degrade signal loss and NF (noise figure) during the implementation of TDD (Time Division Duplexing).

[0019] Furthermore, the antenna device according to the present invention can extend the cell coverage by separating multiple beams in various directions in space, and can reduce the correlation between beams by polarization separation of multiple beams (i.e., spatial polarization separation), thereby further improving the communication quality.

[0020] Furthermore, the antenna device according to the present invention can correct the channel non-reciprocity between the uplink channel and the downlink channel caused by spatial and temporal polarization separation by performing polarization conversion or polarization composition and polarization allocation on the received signal input from the receiving antenna element. Attached Figure Description

[0021] Figure 1 This is a schematic diagram used to illustrate the NF degradation problem in existing antenna devices.

[0022] Figures 2a to 2d These are block diagrams that schematically illustrate exemplary structures of antenna devices that can implement the techniques of this disclosure.

[0023] Figures 3a to 3d These are example diagrams illustrating various antenna modules that can be used in the antenna system of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating the polarization combining and polarization assignment performed in association with a transmitting antenna element according to an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram illustrating polarization and polarization allocation performed in association with a receiving antenna element according to an embodiment of the present invention.

[0026] Figure 6 This is a block diagram of an exemplary structure for polarization synthesis and polarization allocation of a transmitted signal in an antenna device according to an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram illustrating the spatial polarization separation in the horizontal and vertical directions provided by an antenna device according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram illustrating the temporal polarization separation provided by an antenna device according to an embodiment of the present invention.

[0029] Figure 9 This is a diagram illustrating the channel non-reciprocity problem that may occur when different dual polarizations are used between signal transmission and signal reception.

[0030] Figure 10a and Figure 10b This is a schematic diagram illustrating a method for correcting channel non-reciprocity using polarization conversion according to an embodiment of the present invention.

[0031] Figure 11a and Figure 11b This is a schematic diagram illustrating a method for correcting channel non-reciprocity using polarization combining and polarization allocation according to an embodiment of the present invention.

[0032] Figure 12 This is a block diagram of an exemplary structure for performing transmit polarization synthesis calibration in an antenna device according to an embodiment of the present invention.

[0033] Figure 13 This is a flowchart of a method performed by a multi-beam antenna device utilizing quadruped polarization according to an embodiment of the present invention.

[0034] [Explanation of reference numerals in the attached figures]

[0035] 10: Multi-beam antenna device; 110: Digital processing unit

[0036] 120: RF processing unit; 130: Array antenna

[0037] 1310: Antenna Module; 1312: Transmitting Antenna Unit

[0038] 1314: Receiving antenna unit Detailed Implementation

[0039] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. When labeling the drawings, the same reference numerals are used as much as possible, even if the same technical features appear in different drawings. It should also be noted that throughout the specification, detailed descriptions of known technical features and functions are omitted if it is believed that such detailed descriptions would obscure the subject matter of the present invention.

[0040] Furthermore, in describing this invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are merely for distinguishing the corresponding technical features from other technical features and do not limit their essence, order, or sequence. Throughout the specification, if a technical feature "comprises" or "possesses" another technical feature, unless otherwise stated, it can be understood that a technical feature also includes the other technical feature, rather than that a technical feature excludes the other technical feature. Moreover, terms such as "...part" and "module" in the specification refer to a unit capable of performing at least one function, which can be implemented through hardware, software, or a combination of hardware and software.

[0041] Figure 1 This is a schematic diagram used to illustrate the NF degradation problem in existing antenna devices.

[0042] Figure 1 The existing antenna device shown that operates using TDD can be configured to include an antenna (ANT), a filter, a switch (S / W), a power amplifier (PA), an analog-to-digital converter (A / D converter) (not shown), and a digital signal processor (not shown) (implemented by an FPGA).

[0043] An antenna (ANT) can be configured as an array of multiple antenna modules. Each antenna module can be a dual-polarized antenna module composed of two radiating elements with mutually perpendicular geometric orientations (i.e., mutually orthogonal polarization characteristics). When the switch (S / W) is connected to the transmit line (Tx line), the antenna module performs signal transmission; when the switch (S / W) is connected to the receive line (Rx line), the antenna module performs signal reception. Therefore, Figure 1 The antenna device implements TDD functionality based on selective switching operation of a switch (S / W).

[0044] This switching operation causes signal loss during signal transmission or reception, and signal loss also occurs during the transmission of received signals through cables to the back end of the device. This signal loss can worsen the noise figure (NF), leading to limited uplink coverage expansion in wireless communication systems.

[0045] The multi-beam antenna device according to the present invention employs an array antenna composed of an antenna module having a pair of dual-polarized antenna elements, one of which is used for wireless signal transmission, and the other pair of dual-polarized antenna elements is used for wireless signal reception. Therefore, the multi-beam antenna device according to the present invention eliminates the need for switching operations that could worsen signal loss and noise levels during TDD implementation.

[0046] Furthermore, according to the multi-beam antenna device of the present invention, in order to make spatially adjacent transmit beams have different orthogonal polarizations, two kinds of orthogonal polarizations are assigned to the transmit channel, thereby enabling the two kinds of orthogonal polarizations to be spatially separated.

[0047] Figures 2a to 2d These are block diagrams that schematically illustrate exemplary structures of antenna devices that can implement the techniques of this disclosure.

[0048] The multi-beam antenna device 10 can be an M×N multiple-input multiple-output (MIMO) antenna. Therefore, the antenna device 10 can have M transmit channels and M receive channels. The antenna device 10 may include a digital processing unit 110, an RF processing unit 120, and an array antenna 130.

[0049] like Figure 2a and Figure 2b As shown, the digital processing unit 110 may be configured to include a fronthaul interface 1110, a multiple beamforming unit 1120, a polarization combining unit 1130, a polarization allocation unit 1140, an amplitude and phase correction unit 1150, and a polarization conversion unit 1160. Optionally, as shown... Figure 2c and Figure 2d As shown, the digital processing unit 110 may be configured to include a polarization synthesis unit 1170 and a polarization distribution unit 1180 to replace the polarization conversion unit 1160.

[0050] The RF processing unit 120 may be configured to include multiple transmit RF chains 1210 (radio frequency chain; 1210-1 to 1210-M) and multiple receive RF chains 1220 (1220-1 to 1220-M).

[0051] It should be understood that, Figures 2a to 2dThe structure of the antenna device 10 is an exemplary structure drawn for clarity purposes. In another embodiment, the antenna device 10 may also use other arbitrary components. The components of such an antenna device 10 typically use dedicated hardware, such as at least one application-specific integrated circuit (ASIC), radio frequency integrated circuit (RFIC), and / or field-programmable gate array (FPGA). Alternatively, some components may use software executed in programmable hardware or a combination of hardware and software.

[0052] The array antenna 130 may include multiple array elements or antenna elements arranged in multiple rows and columns. In some embodiments, each array element may be a dual-polarized antenna element with dual polarization characteristics. Each array element may be divided into a transmitting antenna element and a receiving antenna element. The transmitting antenna element can be used for signal transmission, and the receiving antenna element can be used for signal reception. The orthogonal polarization characteristics of the transmitting antenna element and the receiving antenna element may be the same or different. In some other embodiments, each array element may be a quadruple-polarized antenna element with quadruple polarization characteristics. The polarization characteristics and structure of the array elements will be described with reference to... Figures 3a to 3d This will be explained later.

[0053] Antenna device 10 can achieve polarization diversity by utilizing the orthogonal polarization characteristics provided by array antenna 130. Antenna device 10 can assign dual orthogonal polarization to the two transmit channels (or transmit signals) associated with each transmit beam. The orthogonal polarization assigned to the transmit channel can be the same as or different from the dual orthogonal polarization characteristics of the transmit antenna elements included in array antenna 130.

[0054] The antenna device 10 can generate a transmit beam with orthogonal polarization characteristics different from those of the transmit antenna element by polarization synthesis. By polarization synthesis of the received signal, it can form a receive beam with orthogonal polarization characteristics different from those of the receive antenna element (that is, it can generate signal components with orthogonal polarization characteristics different from those of the receive antenna element).

[0055] The antenna device 10 assigns two orthogonal polarizations to the transmission channel so that spatially adjacent beams have different orthogonal polarizations, thereby separating the two orthogonal polarizations in space.

[0056] The following explanation assumes that the two types of orthogonal polarization are orthogonal polarization consisting of ±45-degree linear polarization and orthogonal polarization consisting of horizontal / vertical (V / H) linear polarization. However, the technology disclosed herein can also be applied to combinations of such orthogonal linear polarization and orthogonal circular polarization consisting of left / right circular polarization.

[0057] In the following description, the polarization combining section 1130 and the polarization distributing section 1140 located on the transmission path may also be referred to as the transmission polarization combining section 1130 and the transmission polarization distributing section 1140, respectively, and the polarization combining section 1170 and the polarization distributing section 1180 located on the receiving path may also be referred to as the receiving polarization combining section 1170 and the receiving polarization distributing section 1180, respectively.

[0058] Transmit signal processing

[0059] The transmitted signals from the M transmission channels are transmitted in a beamform pattern via a transmission path consisting of a multi-beamforming unit 1120, a polarization combining unit 1130, a polarization allocation unit 1140, an amplitude and phase correction unit 1150, and transmission RF chains 1210-1 to 1210-M, and transmitted through an array antenna 130. Each transmission channel has a corresponding transmission path. The transmitted signal can also be referred to as a downlink signal. The transmission path refers to the path the transmitted signal travels within the antenna device 10. Therefore, the transmission path can also refer to the "transmitted signal travel path" or the "transmitted signal processing path."

[0060] First, the transmit signal input through the fronthaul interface 1110 can be input to the polarization combining unit 1130 for polarization combining. The polarization combining unit 1130 can combine four polarization components for each pair of transmit signals to be radiated through the transmit antenna element described later, and output them to the polarization distribution unit 1140. The polarization components output by the polarization combining unit 1130 can also be referred to as "polarization signals". It should be noted that the polarization components combined in the polarization combining unit 1130 are fed to the array antenna 130 by subsequent components and radiated into free space, realizing actual polarization combining.

[0061] The polarization allocation unit 1140 determines the orthogonal polarizations to be allocated to the two transmission channels (or two transmission signals) associated with each transmission beam, so that spatially adjacent transmission beams have different orthogonal polarizations. The polarization allocation unit 1140 outputs a portion of the four polarization components synthesized in the polarization combining unit 1130, corresponding to the determined orthogonal polarizations, to the two transmission paths. The polarization components output to each transmission path can also be referred to as "polarization components (polarization signals) of the transmission signals," "polarization components (polarization signals) of the transmission channels," or "transmission polarization components (transmission polarization signals)." The orthogonal polarization of the transmission beams can be determined based on the polarization components output by the polarization allocation unit 1140 and the orthogonal polarization characteristics of the transmission antenna elements. Further details will follow. Figure 4 This section explains the polarization synthesis generated in the transmit antenna element based on polarization synthesis and polarization allocation.

[0062] To correct deviations in amplitude and phase characteristics between the transmit RF chains 1210-1 and 1210-M, the polarization components of each transmitted signal are input to the amplitude and phase correction unit 1150 before reaching the transmit RF chains 1210-1 to 1210-M. The amplitude and phase characteristics of the RF transmission path involve the amplitude and phase changes caused by the movement of the RF signal within the RF transmission path provided by the transmit RF chain.

[0063] The amplitude and phase correction unit 1150 can perform the function of correcting amplitude and phase characteristic deviations between the transmit RF chains 1210-1 and 1210-M. Deviations in amplitude characteristics have a very small impact on beamforming, so typically only the phase of all paths is calibrated to make them the same. However, the accuracy of polarization synthesis generated in the antenna array 130 according to the present invention significantly depends on the amplitude and phase of the wireless signal to be synthesized; such amplitude and phase correction will improve the accuracy of polarization synthesis.

[0064] The polarization components of the transmitted signal, after amplitude and phase correction, are converted into an analog signal in the transmit RF chain 1210, and can then be processed as an RF signal. The transmit RF chain 1210 can be configured to include a DAC (digital-to-analog converter), filters, a mixer for up-conversion, a power amplifier (PA), etc.

[0065] The transmitted signal, which has been processed and converted into an analog form in the RF transmission chain 1210, can be radiated in a beamform form through the array antenna 130.

[0066] The multiple beamforming unit 1120 can precode the transmitted signal to form multiple beams in the array antenna 130. The multiple beamforming unit 1120 can be located at different positions on the transmission path of the antenna device 10 based on whether the weighting vector (or precoding matrix) is used in the baseband or the RF band.

[0067] First, such as Figure 2a or Figure 2c For example, the multiple beamforming unit 1122 may be located in the signal transmission path prior to the transmit polarization combining unit 1130. The multiple beamforming unit 1122 performs digital beamforming. In this case, the (baseband) digital transmit signal may be weighted by a weight vector or a precoding matrix and converted into multiple precoded signals in the multiple beamforming unit 1122.

[0068] The digital transmitted signal can be branched into multiple signals with different phases and amplitudes based on the applied weighting vector. Furthermore, the branched signals undergo constructive interference through the array antenna 130 at a specific angle or direction (the direction in which communication resources are to be concentrated), thereby radiating in a beamform. Therefore, the direction and shape of the beam can be determined based on the value of the weighting vector applied to the digital transmitted signal.

[0069] Then, as Figure 2b or Figure 2d For example, the multiple beamforming unit 1124 can be located after the transmit RF chain 1210 during signal transmission. Therefore, the multiple beamforming unit 1124 can perform analog beamforming. In this case, the multiple beamforming unit 1124 can distribute the analog signals received from each transmit RF chain 1210 to multiple paths and can adjust the phase and amplitude of each distributed signal. The beamforming unit 1124 can be configured to include multiple phase shifters for adjusting the phase of each distributed signal and multiple power amplifiers for adjusting the amplitude of each distributed signal. That is, the phase shifters and power amplifiers process weighted vectors in the analog domain. The phase- and amplitude-adjusted analog signals undergo constructive interference at a specific angle or direction through the array antenna 130, thereby radiating in a beamform. Since the transmit RF chain 1210's function can be substantially performed by the multiple beamforming unit 1224 composed of analog components, it can therefore be excluded from the antenna device 10.

[0070] Received signal processing

[0071] The received signals (or uplink signals) corresponding to the M receiving channels are received by the array antenna 130 and then processed through a receiving path consisting of a receiving RF chain 1220, an amplitude and phase correction unit 1150, a polarization conversion unit 1160 (optionally, a receiving polarization combining unit 1170 and a receiving polarization allocation unit 1180), and a multiple beamforming unit 1120. Each receiving channel has a corresponding receiving path. The received signal can also be referred to as the uplink signal. The receiving path refers to the path the received signal travels within the antenna device 10. Therefore, the receiving path can also refer to the "received signal travel path" or the "received signal processing path."

[0072] The analog received signal received through the array antenna 130 can be processed in the corresponding receive RF chains 1220-1 to 1220-M. Each receive RF chain 1220 can be configured to include an ADC (analog to digital converter), a filter, a mixer for down-conversion, a low noise amplifier (LNA), etc.

[0073] The received signal, converted into a digital signal by the receiving RF chain 1220, can be corrected in the amplitude and phase correction unit 1150 for deviations in the amplitude and phase characteristics between the receiving RF chains 1220-1 to 1220-M.

[0074] For transmit and receive beams formed in the same spatial direction, the orthogonal polarization of the transmit beam (changed based on the orthogonal polarization allocation of the transmit polarization allocation unit 1140) and the orthogonal polarization of the received signal (defined based on the orthogonal polarization characteristics of the receive antenna element) can be the same or different. As will be explained later, when the orthogonal polarization of the transmit beam and the orthogonal polarization of the received signal are different, the wireless channel characteristics between the uplink and downlink will be different, and thus downlink / uplink channel reciprocity will not hold.

[0075] like Figure 2a and Figure 2b For example, antenna device 10 may include a polarization conversion unit 1160 that corrects channel impossibilities using polarization conversion. The polarization conversion unit 1160 performs polarization conversion on the received signal output from amplitude and phase correction unit 1150 and can output a polarization-converted signal having the same orthogonal polarization as the transmitted beam.

[0076] For example, when the transmit beam has ±45-degree orthogonal polarization and the receive antenna element has V / H orthogonal polarization characteristics, the polarization conversion unit 1160 performs polarization conversion on the V / H polarized received signal and outputs a polarization-converted signal with the same orthogonal polarization (±45 degrees) as the transmit beam. In another example, when the transmit beam has V / H orthogonal polarization and the receive antenna element has V / H orthogonal polarization characteristics, since the orthogonal polarization of the transmit beam is the same as the orthogonal polarization of the received signal, the polarization conversion unit 1160 may not perform polarization conversion on the received signal.

[0077] Optionally, such as Figure 2c and Figure 2d For example, antenna device 10 may include a polarization combining unit 1170 and a polarization dividing unit 1180 that correct channel non-reciprocity using polarization combining and polarization dividing.

[0078] The polarization combining unit 1170 can combine four polarization components for each pair of received signals received through each receiving antenna element and output them to the polarization distribution unit 1180. The polarization components output by the polarization combining unit 1170 can also be referred to as "polarization signals".

[0079] The polarization allocation unit 1180 can determine the orthogonal polarization to be allocated to the two receiving channels (or two receiving signals) associated with each receiving antenna element. The polarization allocation unit 1180 can allocate the same orthogonal polarization (or orthogonal polarization of the transmitting beam) set in the two corresponding transmitting channels to the two receiving channels.

[0080] The polarization allocation unit 1180 can output two polarization components from the four polarization components synthesized in the polarization synthesis unit 1170, corresponding to a determined orthogonal polarization, which will be transmitted to the DU (digital unit) through the fronthaul interface 1110. The polarization components allocated to each receiving channel can be referred to as "polarization components (polarization signals) of the receiving channel", "polarization components (polarization signals) of the received signal", or "received polarization components (received polarization signals)".

[0081] For example, when the two transmit channels are provided with ±45-degree orthogonal polarization (therefore, the transmit beam has ±45-degree orthogonal polarization) and the receiving antenna element has V / H orthogonal polarization characteristics, the polarization allocation unit 1180 can output two polarization components corresponding to the ±45-degree orthogonal polarization from the four polarization components synthesized in the polarization combining unit 1170. In another example, when the two transmit channels are provided with V / H orthogonal polarization (therefore, the transmit beam has V / H orthogonal polarization) and the receiving antenna element has V / H orthogonal polarization characteristics, the polarization allocation unit 1180 can output two polarization components corresponding to the V / H orthogonal polarization from the four polarization components synthesized in the polarization combining unit 1170.

[0082] The following will be referred to Figure 9 , Figure 10a , Figure 10b , Figure 11a and Figure 11b The operation of the channel non-reciprocity and the polarization conversion unit 1160 used for correction, as well as the operation of the polarization combining unit 1170 and the polarization allocation unit 1180, are explained in detail.

[0083] The received signal may include multiple signals corresponding to the associated receiving antenna element and having different phases and amplitudes. After adjusting the phases and amplitudes of the multiple signals, the multiple beamforming unit 1120 can accumulate the adjusted signals to form or restore the received signal. This process can be understood as the reverse of the process by which the multiple beamforming unit 1120 forms multiple signals with different phases and amplitudes from the transmitted signal. For this purpose, as... Figure 2a and Figure 2c As shown, the multi-beamforming unit 1122 is located after the polarization combining unit 1160 and the receiving polarization allocation unit 1180 in the receiving path, and can perform digital beamforming, or as shown in the diagram. Figure 2b and Figure 2d As shown, the multiple beamforming unit 1122 is located between the array antenna 130 and the receiving RF chain 1220 in the receiving path, and can perform simulated beamforming. Figure 2b In this context, the function of the receiving RF chain 1220 can be substantially performed by the multi-beamforming unit 1224 composed of analog components, and therefore can also be excluded from the antenna device 10.

[0084] DU and RU

[0085] Furthermore, a "stand-alone base station" refers to a physical system containing the signal processing functions corresponding to the digital unit (DU) and radio unit (RU), respectively, located within the target service area. Conversely, according to the Cloud Radio Access Network (C-RAN) architecture, the DU and RU are physically separated, with only the RU located within the target service area. The centralized DU, i.e., the BBUpool, has control and management functions over multiple RUs used to form their own independent cells.

[0086] The DU, responsible for digital signal processing and resource management control, connects to the core network via backhaul. The RU, responsible for radio signal processing, converts the digital signals received from the DU into radio frequency signals according to the frequency bandwidth and amplifies them. It also converts the RF signals received from the antenna into digital signals and transmits them to the DU.

[0087] Antenna device 10 can be installed in a stand-alone base station where the DU and RU are contained in a single physical system, or in a RU in a C-RAN structure where the DU and RU are physically separated. The following description focuses on an example where antenna device 10 is installed in a RU in a C-RAN structure.

[0088] Baseband signals can be signals processed through baseband processes such as scrambling, modulation, and layer mapping. Scrambling is equivalent to encrypting the baseband signal using a scrambled signal to distinguish between a base station and a terminal. Modulation is equivalent to modulating the scrambled signal into multiple modulation symbols. The scrambled signal can be modulated using BPSK (binary phase shift keying), QPSK (quadrature phase shift keying), or 16QAM / 64QAM (quadrature amplitude modulation) methods, depending on the type of signal input to the modulation mapper (not shown) and / or the channel state. Layer mapping is equivalent to mapping the modulated signal to one or more transmission layers to separate the signal according to antenna type. For modulation symbols obtained through modulation, a process of mapping the modulation symbols to resource elements can also be performed.

[0089] When the antenna device 10 is located in the RU of a C-RAN structure, the above process can be performed in a centralized DU. Conversely, when the antenna device 10 is located in a stand-alone base station, the above process can be performed in a DU within the base station.

[0090] Signal or data exchange between the DU and RU can be achieved through fronthaul or a fronthaul link. A fronthaul link is a link used in a cellular radio access network to connect the DU and RU. The fronthaul interface 1110 of the antenna device 10 can be implemented in accordance with standards such as CPRI (Common Public Radio Interface), eCPRI (enhanced CPRI), ORI (Open Radio Equipment Interface), and OBSAI (Open Base Station Architecture Initiative).

[0091] When the antenna device 10 of the present invention is implemented in an RU, the antenna device 10 can be divided into a digital processing unit 110, an RF processing unit 120, and an array antenna 130.

[0092] The RF processing unit 120 is responsible for analog signal processing of the transmitted and received signals. The RF processing unit 120, as follows... Figure 2a The diagram may include RF chains 1210 and 1220, as shown. Figure 2b The diagram may include RF chains 1210 and 1220 and a multiple beamforming unit 1124.

[0093] The digital processing unit 110 is responsible for the digital signal processing of transmitted and received signals. The digital processing unit 110 can be constructed using a digital front end (DFE). A DFE replaces existing analog function blocks with digital signal processing (DSP) blocks. When the digital processing unit 110 is constructed using a DFE, not only can the actual time, power consumption, and area be reduced, but the flexibility to support multiple modes and multiple frequency bands can also be ensured.

[0094] The digital processing unit 110 can further perform IFFT (inverse fast fourier transform) and FFT operations on the polarization-converted signal. Furthermore, to prevent inter-symbol interference (ISI), the digital processing unit 110 can insert a guard interval. Therefore, the digital processing unit 110 can be configured to further include an IFFT unit (not shown) / an FFT unit (not shown) and a cyclic prefix (not shown).

[0095] Antenna elements of an array antenna

[0096] Figures 3a to 3d This is a diagram illustrating the various structures and orthogonal polarization characteristics of the antenna module 1310 that can be used in the array antenna 130 of the antenna system of the present invention.

[0097] like Figures 3a to 3d As shown, the antenna module 1310 can be configured by pairing a transmitting antenna unit 1312, which is equivalent to a transmitting antenna, and a receiving antenna unit 1314, which is equivalent to a receiving antenna. The transmitting antenna unit 1312 can be connected to the transmitting lines Tx1 and Tx2 and is used to transmit signals, and the receiving antenna unit 1314 can be connected to the receiving lines Rx1 and Rx2 and is used to receive signals.

[0098] The transmitting antenna element 1312 is a dual-polarized antenna element comprising two radiating elements having mutually orthogonal polarization characteristics, and the receiving antenna element 1314 is also a dual-polarized antenna element comprising two radiating elements having mutually orthogonal polarization characteristics.

[0099] The orthogonal polarization characteristics of the transmitting antenna element 1312 and the receiving antenna element 1314 may be different (for example, refer to...). Figure 3a (b) and (c)). For example, the radiating elements included in the transmitting antenna element 1312 may have polarization characteristics of +45 degrees and -45 degrees, respectively, and the radiating elements included in the receiving antenna element 1314 may have polarization characteristics of V and H, respectively. In another example, the radiating elements included in the transmitting antenna element 1312 may have polarization characteristics of V and H, respectively, and the radiating elements included in the receiving antenna element 1314 may have polarization characteristics of +45 degrees and -45 degrees, respectively. That is, the antenna module 1310 can provide two kinds of orthogonal polarization characteristics, including dual orthogonal polarization of the transmitting antenna element 1312 and dual orthogonal polarization of the receiving antenna element 1314.

[0100] The orthogonal polarization characteristics of the transmitting antenna element 1312 and the receiving antenna element 1314 can also be the same (see reference). Figure 3a (a) and (d)). In embodiments employing this antenna module 1310, as shown in reference Figure 4 As described later, depending on the polarization composition of the transmitted signal to be transmitted through transmission lines Tx1 and Tx2, the beam radiated by the transmitting antenna element 1312 can have a dual orthogonal polarization direction different from the dual polarization characteristics of the transmitting antenna element 1312. Therefore, when utilizing... Figure 3a In the case of antenna module 1310 shown in (a) and (d), antenna device 10 can still use different dual orthogonal polarizations between the transmit beam and the receive beam.

[0101] Figure 3a In the antenna module 1310 shown, the two radiating elements constituting the transmitting antenna unit 1312 are arranged to cross each other at a first intersection point, and the radiating elements constituting the receiving antenna unit 1314 are arranged to cross each other at a second intersection point. The smaller the distance between the first intersection point and the second intersection point, the higher the area utilization efficiency of the antenna module 1310.

[0102] Reference Figure 3b The pair of radiating elements used to form the receiving antenna unit 1314 can be arranged as follows: (1) arranged near the left and upper sides of the transmitting antenna unit 1312 (refer to Figure 3b(a) or (2) arranged near the left and lower sides of the transmitting antenna element 1312 (see reference) Figure 3b (b) or (3) arranged near the right and top sides of the transmitting antenna element 1312 (see reference) Figure 3b (c) or (4) arranged near the right and lower sides of the transmitting antenna element 1312 (see reference) Figure 3b (d)

[0103] Reference Figure 3c The pair of radiating elements used to form the transmitting antenna unit 1312 can be arranged as follows: (1) arranged near the upper left and lower left sides of the receiving antenna unit 1314 (refer to Figure 3c (a) or (2) arranged near the lower left and lower right sides of the receiving antenna element 1314 (see reference) Figure 3c (b) or (3) arranged near the upper left and upper right sides of the receiving antenna element 1314 (see reference) Figure 3c (c) or (4) arranged near the upper right and lower right sides of the receiving antenna element 1314 (see reference) Figure 3c (d)

[0104] As mentioned above, Figure 3b and Figure 3c The antenna module 1310 shown is configured such that one antenna element (1312 or 1314) is positioned close to the side of another antenna element (1314 or 1312), compared to Figure 3a The antenna module 1310 shown can improve the area utilization of the array antenna 130. In addition, the improved area utilization brings convenience in manufacturing, installation, and maintenance.

[0105] Figure 3d In the antenna module 1310 shown, the two radiating elements constituting the transmitting antenna unit 1312 and the radiating element constituting the receiving antenna unit 1314 intersect at a crossroads 1316. Figure 3d The arrangement compared to Figures 3a to 3c The arrangement can maximize the utilization of the area.

[0106] In addition, it should be noted that, in reference Figures 3a to 3d In the above description, the positions of the transmitting antenna unit 1312 and the receiving antenna unit 1314 can be interchanged.

[0107] Polarization synthesis and polarization distribution

[0108] Figure 4 This is a schematic diagram illustrating the polarization combining and polarization assignment performed in association with a transmitting antenna element according to an embodiment of the present invention. Figure 5This is a schematic diagram illustrating polarization and polarization allocation performed in association with a receiving antenna element according to an embodiment of the present invention.

[0109] As mentioned above, the transmit polarization combining unit 1130 can combine two transmit signals to be transmitted through a transmit antenna unit 1312 to form four different polarization components and output them.

[0110] Reference Figure 4 The emission polarization synthesis unit 1130 can synthesize different polarization components ("S1", "S2", "S1+S2", and "S1+S2e") from the emission signals S1 and S2. jπ The output is then defined as follows: "S1" and "S2" are used to generate a beam with the same polarization direction as the transmitting antenna element 1312, and "S1+S2" and "S1+S2e" are used to generate the beam. jπ "Used to generate a beam with a polarization direction that is different from the polarization characteristics of the transmitting antenna element 1312."

[0111] The polarization composition performed in the emission polarization composition unit 1130 can be achieved through matrix operations of the following mathematical formula 1.

[0112]

Mathematical Formula 1

[0113]

[0114] In the above mathematical formula 1, This represents the PVCD (polarization vector composition-decomposition) matrix. Specifically, to prevent the third and fourth polarization components (“S1+S2” and “S1+S2e”) from being combined, this is used. jπ As the power of PD increases, scaling factors can be used in the third and fourth rows of the PD matrix. The scaling factor can be...

[0115] The transmit polarization distribution unit 1140 can output two polarization components to be radiated by the two radiating elements of the transmit antenna unit 1312 to two transmit paths from the four polarization components of the transmit signals S1 and S2 output by the transmit polarization combining unit 1130.

[0116] For example, the emission polarization distribution unit 1140 emits from four polarization components ("S1", "S2", "S1+S2", "S1+S2e"). jπ The output of the text is: (1) "S1" and "S2" (refer to...). Figure 4 (a) or (2) “S1+S2” and “S1+S2e” jπ ” (refer to Figure 4(b)

[0117] Based on the polarization composition output from the transmit polarization distribution unit 1140, the beam radiated from the transmit antenna element 1312, which has ±45-degree orthogonal polarization characteristics, has ±45-degree orthogonal polarization or V / H orthogonal polarization.

[0118] like Figure 4 As shown in (a), if polarization components “S1” and “S2” are assigned to the transmission channel, the polarization component “S1” radiated by the radiating element with +45° polarization characteristics can form a beam pattern with +45° polarization, and the polarization component “S1” radiated by the radiating element with -45° polarization characteristics can form a beam pattern with -45° polarization. That is, the transmitting antenna element 1312 with ±45° orthogonal polarization characteristics can form a beam pattern with ±45° orthogonal polarization.

[0119] like Figure 4 As shown in (b), if the polarization components “S1+S2” and “S1+S2e” are... jπ "Assigned to the transmission channel, the beam radiated by the radiating element with +45° polarization characteristics, forming a polarization component "S1+S2", and the beam radiated by the radiating element with -45° polarization characteristics, forming a polarization component "S1+S2e", are compared with those radiated by the radiating element with -45° polarization characteristics." jπ Polarization synthesis occurs between the beams.

[0120] Specifically, for polarization component "S1", the first beam radiated by a radiating element with +45° polarization characteristics has a +45° polarization orientation, and the second beam radiated by a radiating element with -45° polarization characteristics has a -45° polarization orientation. Therefore, the first and second beams are combined to present a composite beam with a V polarization orientation. For polarization component "S2", the third beam radiated by a radiating element with +45° polarization characteristics has a +45° polarization orientation, and the fourth beam radiated by a radiating element with -45° polarization characteristics has a "-45°+π" polarization orientation. Therefore, the third and fourth beams are combined to present a composite beam with a V polarization orientation.

[0121] Furthermore, when the receiving antenna element 1314 receives wireless signals S1 and S2 in free space, the orthogonal polarization directions of the received signals a and b will be determined based on the orthogonal polarization characteristics of the receiving antenna element 1314. For example, when the dual polarization characteristics of the receiving antenna element 1314 are V / H orthogonal polarization, the received signals will have V / H orthogonal polarization.

[0122] Reference Figure 5For wireless signals S1 and S2, the received signal (a) captured by the radiating element with receiving antenna element 1314V polarization includes the V-polarized S1 signal component S1(V) and the V-polarized S2 signal component S2(V), and the received signal (b) captured by the radiating element with H polarization includes the H-polarized S1 signal component S1(H) and the H-polarized S2 signal component S2(H).

[0123] As previously described, the receiving polarization combining unit 1170 can combine four different polarization components based on two received signals a and b received by a receiving antenna element 1314 and output them. The polarization component combining performed in the receiving polarization combining unit 1170 can be achieved through matrix operations of mathematical formula 1.

[0124] like Figure 5 As shown, the receiving polarization synthesis unit 1170 can synthesize different polarization components ("a", "b", "a+b", and "a+a+be") based on the received signals a and b of the RF signals S1 and S2. jπ The output is then displayed. Here, "a" and "b" are polarization components with the same polarization direction as the receiving antenna element 1314, and "a+b" and "a+a+be" are polarization components. jπ "is a polarization component with a polarization direction different from that of the receiving antenna element 1314.

[0125] Specifically, polarization component “a” has a V-polarized S1 signal component S1(V) and a V-polarized S2 signal component S2(V), and polarization component “b” has an H-polarized S1 signal component S1(H) and an H-polarized S2 signal component S2(H).

[0126] Furthermore, the polarization component “a+b” has: (1) a +45° polarized S1 signal component S1(+45°) synthesized from V-polarized S1 signal component S1(V) and H-polarized S1 signal component S1(H); and (2) a +45° polarized S2 signal component S2(+45°) synthesized from V-polarized S2 signal component S2(V) and H-polarized S2 signal component S2(H).

[0127] In addition, the polarization component "a+a+be jπ "It has: (1) a -45° polarized S1 signal component S1(-45°) synthesized from a V-polarized S1 signal component S1(V) and an H+π-polarized S1 signal component S1(H+π); and (2) a -45° polarized S2 signal component S2(-45°) synthesized from a V-polarized S2 signal component S2(V) and an H+π-polarized S2 signal component S2(H+π).

[0128] The receiving polarization allocation unit 1180 can output two polarization components from the polarization components of the received signals a and b output by the receiving polarization combining unit 1170 to two receiving paths. For example, the receiving polarization allocation unit 1180 can output two polarization components ("a", "b", "a+b", and "a+a+be") from four polarization components. jπ Output in ”): (1) “a” and “b” (refer to) Figure 5 (a)) or (2) "a+b" and "a+a+be jπ ” (refer to Figure 5 (b)

[0129] like Figure 5 As shown in (a), if polarization components “a” and “b” are assigned to the receiving channel, then for RF signals S1, S2, the receiving channel can output orthogonally polarized signal components “S1(V), S2(V)” and “S1(H), S2(H)” that are the same as the orthogonal polarization characteristics of the receiving antenna element 1314.

[0130] like Figure 5 As shown in (b), if the polarization components “a+b” and “a+a+be” are... jπ "When assigned to the receiving channel, for RF signals S1, S2, S3, the receiving channel can output synthesized orthogonal polarization signal components "S1(+45°), S2(+45°)" and "S1(-45°), S2(-45°)" which are different from the orthogonal polarization characteristics of the receiving antenna element 1314.

[0131] Figures 2a to 2d The antenna device 10 is shown to include a transmit polarization combining unit 1130 and a transmit polarization distributing unit 1140, which uniformly performs polarization combining and polarization distributing on all transmitted signals or transmit channels.

[0132] However, in another embodiment, the antenna device 10 may also have a structure including multiple transmit polarization combining sections and multiple transmit polarization distributing sections to perform polarization combining and polarization distributing on the transmit signals or transmit channels associated with each transmit beam. Similarly, the antenna device 10 may also have a structure including multiple receive polarization combining sections and multiple receive polarization distributing sections. An example of such a structure is... Figure 6 As shown.

[0133] Figure 6 This is a block diagram of an exemplary structure for polarization synthesis and polarization allocation of a transmitted signal in an antenna device according to an embodiment of the present invention.

[0134] Reference Figure 6The antenna device may be configured to include multiple polarization combining units 1130-1 to 1130-M, multiple polarization allocation units 1140-1 to 1140-M, and a polarization allocation control unit 1142. The polarization allocation control unit 1142 uniformly manages the polarization allocation of the transmitted signal performed by the multiple transmit polarization combining units 1130-1 to 1130-M.

[0135] The polarization allocation control unit 1142 can determine the orthogonal polarization of each transmission channel based on the number of beams and the orthogonal polarization of the reference beam. The number of beams refers to the number of beams generated by the array antenna 130, and the reference beam can be a predefined beam among multiple beams (e.g., the transmission beam associated with the first and second transmission channels among M transmission channels). To ensure that adjacent transmission beams in the multiple transmission beams have different orthogonal polarizations, the polarization allocation control unit 1142 can determine the orthogonal polarization of each transmission channel.

[0136] In order to control the allocation of orthogonal polarization to the transmission channel, the polarization allocation control unit 1142 can generate an allocation control signal. The polarization allocation control unit 1142 can send the allocation control signal to the polarization allocation units 1140-1 to 1140-M. Each polarization allocation unit 1140-1 to 1140-M can output the polarization component corresponding to the orthogonal polarization indicated by the allocation control signal from the four polarization components generated in the corresponding polarization combining units 1130-1 to 1130-M.

[0137] The polarization components output by each polarization distribution unit 1140-1 to 1140-M can be provided to the corresponding transmitting antenna unit 1312 via subsequent components. The transmitted signal assigned with orthogonal polarization can be radiated as a beam in different directions in free space through the transmitting antenna unit 1312. This spatial polarization separation can be achieved by at least one direction, either horizontal or vertical.

[0138] Figure 7 This is a schematic diagram illustrating the spatial polarization separation in the horizontal and vertical directions provided by an antenna device according to an embodiment of the present invention.

[0139] like Figure 7 As shown, the antenna device 10 can use the array antenna 130 to form c beams separated horizontally, corresponding to c sectors, and each of the c sectors can form d beams separated vertically. That is, the antenna device 10 can provide 3D beamforming. The number of beams spatially separated vertically by each sector can be the same or different. Therefore, the coverage area of ​​the antenna device 10 can be divided into a maximum of c×d sub-sectors.

[0140] Beams separated horizontally have different orthogonal polarizations from adjacent beams (i.e., spatial polarization separation in the horizontal direction), thus significantly reducing the correlation between adjacent beams in the horizontal direction. Furthermore, within each sector, beams separated vertically have different orthogonal polarizations from adjacent beams (i.e., spatial polarization separation in the vertical direction), further significantly reducing the correlation between adjacent beams in the vertical direction. Moreover, beams with the same orthogonal polarization between adjacent sectors (e.g., the first beam of the first sector and the second beam of the second sector) also exhibit significantly reduced correlation due to sufficient spacing in both the horizontal and vertical directions.

[0141] It is important to note that previously, due to the high correlation between ±45° orthogonal polarization and H / V orthogonal polarization, no antenna devices attempting to use both orthogonal polarizations simultaneously were explored. The antenna device 10 according to the invention improves the correlation between orthogonal polarizations by allocating different orthogonal polarizations among spatially adjacent beams, enabling polarization reuse that effectively utilizes the polarization diversity provided by two orthogonal polarizations (i.e., four different polarizations). The term "polarization reuse" refers to frequency reuse.

[0142] Figure 8 This is a schematic diagram illustrating the temporal polarization separation provided by an antenna device according to an embodiment of the present invention.

[0143] The antenna device 10 according to the invention assigns two orthogonal polarizations to the transmit channel and the receive channel so that the transmit beam and the receive beam formed in the same direction have different orthogonal polarizations, thereby separating the two orthogonal polarizations in time.

[0144] Figure 8 In the diagram, the area Tx represented by the slash indicates the time interval for transmitting signals through the transmitting antenna element 1312, and the area Rx not represented by the slash indicates the time interval for receiving signals through the receiving antenna element 1314.

[0145] Figure 8 In the example, ±45 degrees of orthogonal polarization is used during the transmit time interval, and vertical / horizontal orthogonal polarization is used during the receive time interval, separating and using the different orthogonal polarizations in time. Conversely, it should be noted that ±45 degrees of orthogonal polarization is used during the receive time interval, and vertical / horizontal orthogonal polarization is used during the transmit time interval.

[0146] In particular, according to the antenna device 10 of the present invention, for TDD operation, the orthogonal polarization characteristics between the transmitting antenna element and the receiving antenna element can be different from each other, so the orthogonal polarization used in signal transmission and signal reception can be different from each other.

[0147] Channel non-reciprocity correction

[0148] Channel reciprocity is based on the premise that downlink and uplink channels with the same frequency bandwidth have identical channel characteristics. In other words, channel reciprocity refers to the property that downlink and uplink channels have similar characteristics.

[0149] By utilizing channel reciprocity, a base station can obtain a downlink channel response by utilizing an uplink channel response, or a terminal can obtain an uplink channel response by utilizing a downlink channel response. Therefore, channel reciprocity can be considered its greatest advantage compared to FDD (Frequency Division Duplexing) and TDD (Time Division Duplexing).

[0150] Figure 9 This is a schematic diagram illustrating the channel non-reciprocity problem that may occur when an antenna device uses different dual polarizations between signal transmission and signal reception.

[0151] As previously described, the antenna device according to the invention utilizes spatial polarization separation and temporal polarization separation. Therefore, the orthogonal polarization of the transmit beam formed in a spatial direction and the orthogonal polarization characteristics of the receive antenna element used to receive wireless signals from that spatial direction can differ. For example, for a spatial direction, the transmit beam may have ±45° orthogonal polarization, while the receive antenna element may have H / V orthogonal polarization characteristics. Another example is that the transmit beam may have H / V orthogonal polarization, and the receive antenna element may have ±45° orthogonal polarization characteristics. As mentioned above, if different orthogonal polarizations are used in the downlink and uplink, the wireless channel characteristics will differ between the uplink and downlink, thus channel reciprocity between the downlink and uplink does not hold. That is, channel non-reciprocity occurs.

[0152] This failure of channel reciprocity (i.e., the occurrence of channel non-reciprocity) is not a problem when beamforming is not performed or when 5G NR performs beamforming based on the CSI-RS (channel state information-reference signal) transmitted from the base station gNB to the terminal UE. However, when beamforming is performed based on the SRS (sounding reference signal), the failure of channel reciprocity can lead to a degradation in the performance of the antenna device.

[0153] The Channel State Signal (SRS) is an uplink reference signal transmitted by a UE to the gNB to estimate the uplink channel state. The UE can periodically or non-periodically transmit the SRS to the gNB and inform it of the uplink channel state information. The gNB, upon receiving the SRS, can obtain the Channel State Information (CSI) of the uplink channel and use the obtained CSI to determine the weighting vector for downlink beamforming.

[0154] Therefore, when channel reciprocity is not met, using the weighted vector obtained by SRS for downlink beamforming will lead to a decrease in the performance of the antenna device.

[0155] To address this problem, the antenna device 10 according to an embodiment of the present invention performs signal processing on the received signal to make the orthogonal polarization of the received signal consistent with the orthogonal polarization of the transmission channel (or transmission beam), thereby correcting channel non-reciprocity (i.e., ensuring channel reciprocity).

[0156] As previously mentioned, channel non-reciprocity correction can be implemented based on polarization conversion of polarization conversion unit 1160, or optionally based on polarization combining unit 1170 and polarization allocating unit 1180. Referring here... Figure 10a , Figure 10b , Figure 11a and Figure 11b An exemplary structure and its operation for correcting channel non-reciprocity will be described.

[0157] The exemplary structure of Figure 10 includes a polarization conversion unit 1160 for performing a channel non-reciprocity correction function.

[0158] Figure 10a In the example, the orthogonal polarization characteristics (V / H) of the receiving antenna element 1314 are different from the orthogonal polarization (±45°) of the radio waves (or transmit beams) of the downlink channel, requiring channel non-reciprocity or reciprocity correction.

[0159] Reference Figure 10aTwo digital transmit signals, each with ±45° orthogonal polarization, are processed by the transmit RF chain 1210 and fed to the transmit antenna unit 1312. If the transmit RF chain inputs a polarization component corresponding to ±45° orthogonal polarization, the transmit antenna unit 1312 possesses ±45° orthogonal polarization characteristics, and the radio waves of the downlink channel have ±45° orthogonal polarization. The receive antenna unit 1314 receives the radio waves of the uplink channel and outputs an analog receive signal. The receive antenna unit 1314 has V / H orthogonal polarization characteristics, and the analog receive signal corresponds to the V / H orthogonal polarization component of the radio wave. The analog receive signal is processed by the receive RF chain 1220 and converted into a digital receive signal.

[0160] The polarization conversion unit 1160 performs polarization conversion on the digital received signal and outputs a polarization-converted signal having the same orthogonal polarization as the downlink channel. The polarization conversion performed in the polarization conversion unit 1160 can be achieved through matrix operations of the following mathematical formula 2.

[0161]

Mathematical Formula 2

[0162]

[0163] In the above mathematical formula 2, a and b are the digital received signals of the input polarization conversion unit 1160. a+b and a+a+be jπ This is the received signal of polarization conversion output from the polarization conversion unit 1160. Furthermore, This represents the PD (polarization decomposition) matrix used for orthogonal polarization conversion. However, to avoid increasing the power of the received signal during polarization transition, scaling factors can be used in all elements of the PD matrix. These scaling factors can be...

[0164] Figure 10b In the example, the orthogonal polarization characteristics (V / H) of the receiving antenna element 1314 are the same as the orthogonal polarization (V / H) of the radio waves (or transmit beam) of the downlink channel, so there is no need for channel non-reciprocity or reciprocity correction. Therefore, the polarization conversion unit 1160 can directly output the input digital received signal without polarization conversion.

[0165] exist Figure 11a and Figure 11b In the exemplary structure, the channel non-reciprocity correction function can be implemented by the polarization allocation control unit 1142, the receiving polarization synthesis unit 1170, and the receiving polarization allocation unit 1180.

[0166] Figure 11aIn the example, the orthogonal polarization characteristics (V / H) of the receiving antenna element 1314 are different from the orthogonal polarization (±45°) of the radio waves (or transmit beams) of the downlink channel, thus requiring channel non-reciprocity or reciprocity correction. Therefore, the orthogonal polarization differs between the signal input to the receiving polarization combining unit 1170 and the signal output from the receiving polarization distributing unit 1180.

[0167] Reference Figure 11a The receiving polarization combining unit 1170 generates four polarization components for a pair of transmitted signals. In response to the control signal from the polarization allocation control unit 1142, the receiving polarization allocation unit 1140 outputs two polarization components corresponding to ±45° orthogonal polarization. These two polarization components are fed to the transmitting antenna element 1312 via the transmitting RF chain 1210. The transmitting antenna element 1312 has ±45° orthogonal polarization characteristics, and the radio waves (or transmitted beams) of the downlink channel have ±45° orthogonal polarization.

[0168] The receiving antenna unit 1314 receives radio waves from the uplink channel and outputs two analog received signals. The receiving antenna unit 1314 has V / H orthogonal polarization characteristics, and the two analog received signals correspond to the V / H orthogonal polarization components of the radio waves. The two analog received signals are converted into two digital received signals by the RF signal processing of the receiving RF chain 1220. The receiving polarization combining unit 1170 can synthesize four orthogonal polarization components based on the two digital received signals.

[0169] To correct for channel non-reciprocity, polarization allocation control unit 1142 selects the same orthogonal polarization selected by transmit polarization allocation unit 1140 (i.e., ±45° orthogonal polarization), and transmits an allocation control signal indicating the selected orthogonal polarization to receive polarization allocation unit 1180. Receiver polarization allocation unit 1180 can output two polarization components from the four orthogonal polarization components that correspond to the orthogonal polarization indicated by the allocation control signal (i.e., ±45° orthogonal polarization).

[0170] Figure 11b In the example, the orthogonal polarization characteristics (V / H) of the receiving antenna element 1314 are the same as the orthogonal polarization (V / H) of the radio waves (or transmit beams) of the downlink channel, so there is no need to perform channel non-reciprocity or reciprocity correction. Therefore, the orthogonal polarization is the same between the signal input to the receiving polarization combining unit 1170 and the signal output from the receiving polarization dividing unit 1314.

[0171] Reference Figure 11bIn response to the control signal from the polarization allocation control unit 1142, the device receives two polarization components output by the polarization allocation unit 1140, corresponding to V / H orthogonal polarization. These two polarization components are fed to the transmit antenna unit 1312 via the transmit RF chain 1210. The transmit antenna unit 1312 has ±45° orthogonal polarization characteristics, and the radio waves (or transmit beams) of the downlink channel based on polarization synthesis have V / H orthogonal polarization.

[0172] The receiving antenna unit 1314 receives radio waves from the uplink channel and outputs two analog received signals. The receiving antenna unit 1314 has V / H orthogonal polarization characteristics, and the two analog received signals correspond to the V / H orthogonal polarization components of the radio waves. The two analog received signals are processed by the receiving RF chain 1220 to convert them into two digital received signals. The receiving polarization combining unit 1170 can synthesize four orthogonal polarization components based on the two digital received signals.

[0173] The polarization allocation control unit 1142 selects the same orthogonal polarization (i.e., V / H orthogonal polarization) as the orthogonal polarization selected for the transmitting polarization allocation unit 1140, and transmits an allocation control signal indicating the selected orthogonal polarization to the receiving polarization allocation unit 1180. The receiving polarization allocation unit 1180 can output two polarization components from the four orthogonal polarization components that correspond to the orthogonal polarization (i.e., V / H orthogonal polarization) indicated by the allocation control signal.

[0174] As described above, the antenna device 10 according to the present invention performs polarization conversion on the received signal input from the receiving antenna element 1314 to obtain polarization combining and polarization allocation, and can output signal components corresponding to orthogonal polarization that are the same as those of the downlink channel (or the transmit beam or the transmit channel). This corrects for channel non-reciprocity between the uplink channel and the downlink channel, thereby preventing performance degradation of transmit beamforming performed based on the uplink channel state information (CSI) estimated from the SRS received from the uplink channel. Furthermore, by implementing signal processing of the received signal in the antenna device 10 in the RU to correct channel non-reciprocity, channel reciprocity can be ensured in the DU.

[0175] Amplitude and phase calibration

[0176] As mentioned above, Figure 2a and Figure 2b In this circuit, the amplitude and phase correction unit 1150 can correct the deviations in amplitude and phase of polarization generated during the movement of the RF signal along the RF path.

[0177] The amplitude and phase correction unit 1150 may be composed of a single component that uniformly performs amplitude and phase correction on multiple transmitted / received signals or transmitted / received channels. Alternatively, it may be composed of multiple modules that perform amplitude and phase correction on each of the multiple transmitted / received signals or transmitted / received channels separately.

[0178] The accuracy of polarization synthesis generated in the antenna array 130 according to the invention depends on the scale of the amplitude and phase of the synthesized radio signal. Such amplitude and phase correction can improve the accuracy of polarization synthesis. Therefore, amplitude and phase correction can be applied to all RF paths, and can also be selectively applied only to the transmit paths that require polarization synthesis among multiple RF transmit paths, and to the receive paths that require channel non-reciprocity correction among multiple RF receive paths.

[0179] Figure 12 This is a block diagram of an exemplary structure for performing transmit polarization synthesis calibration in an antenna device according to an embodiment of the present invention.

[0180] like Figure 12 As shown, the amplitude and phase correction unit 1150 may be configured to include a correction control unit 1152 and a plurality of correction execution units 1154.

[0181] The correction control unit 1152 can uniformly manage the amplitude and phase corrections performed on multiple transmission channels. The correction control unit 1152 compares the polarization component output from the transmission polarization allocation unit 1140 with the polarization component output from the transmission RF chain 1210, and generates a correction control signal to control the amplitude and phase corrections to be performed by the correction execution unit 1154. The correction control signal may include amplitude and phase values ​​for compensation.

[0182] The correction control unit 1152 can transmit control signals to each correction execution unit 1154. Each correction execution unit 1154 can perform amplitude and phase correction based on the correction control signals.

[0183] As mentioned earlier, amplitude and phase corrections are selectively applied only to transmission paths whose orthogonal polarization assigned in the transmission path differs from the orthogonal polarization characteristics of the transmitting antenna element (thus polarization synthesis occurs in the transmitting antenna element).

[0184] Therefore, when the transmitting antenna element does not generate polarization synthesis, the correction control unit 1152 does not transmit a correction control signal to the associated correction execution unit 1154, or it may transmit a correction control signal to the associated correction execution unit 1154 with the compensation amplitude value and phase value set to 0 (zero).

[0185] Reference Figure 12The polarization allocation unit 1140-1 outputs polarization components "a" and "b" to the two transmission channels respectively, so that the transmitted beam radiated in the associated transmit antenna element 1312 is not accompanied by polarization synthesis. Therefore, the correction control unit 1152 does not transmit a correction control signal to the correction execution unit 1154-1, or it can transmit a correction control signal to the correction execution unit 1154-1 with the compensation amplitude value and phase value set to 0 (zero) respectively. Conversely, the polarization allocation unit 1140-E can output polarization components "i+j" and "i+je" to the two transmission channels respectively. jπ Therefore, the transmitted beam radiated in the associated transmitting antenna element 1312 is accompanied by polarization synthesis. Thus, the correction control unit 1152 compares the polarization component output from the transmitting polarization distribution unit 1140-E with the polarization components output from the transmitting RF chains 1210E-1 and 1210E-2, calculates the deviation between the transmitting RF chains 1210E-1 and 1210E-2, and generates a correction control signal for controlling the amplitude and phase corrections to be performed by the correction execution unit 1154-E. Based on the correction control signal, the correction execution unit 1154-E can adjust the amplitude and phase of the polarization component output from the transmitting polarization distribution unit 1140-E, thereby correcting the deviation in the amplitude and phase characteristics of the RF path between the transmitting RF chains 1210E-1 and 1210E-2.

[0186] Figure 12 The structure and operation method shown can also be applied to correct deviations in the amplitude and phase characteristics of the RF path between the receiving RF chains 1210-1 and 1210-M.

[0187] This amplitude and phase correction function enables more accurate polarization combining and channel non-reciprocity correction generated in the antenna array 130. Furthermore, the amplitude and phase correction function is selectively applied only to the transmit path accompanied by polarization combining and the receive path accompanied by channel non-reciprocity correction, thereby reducing the computational burden caused by the correction control unit 1152 generating the correction control signal, and thus enabling rapid amplitude and phase correction.

[0188] Figure 13 This is a flowchart illustrating a method performed by a multi-beam antenna device utilizing quadruple polarization according to an embodiment of the present invention. The multi-beam antenna device has an array antenna including transmitting antenna elements for forming multiple transmitting beams and receiving antenna elements for forming multiple receiving beams.

[0189] The multi-beam antenna device can generate multiple transmit polarization components based on the transmit signals corresponding to a pair of transmit channels associated with each transmit beam (S1310).

[0190] The multi-beam antenna device can output a pair of transmission polarization components corresponding to the first orthogonal polarization or a pair of transmission polarization components corresponding to the second orthogonal polarization among the multiple transmission polarization components associated with each transmission beam, so that spatially adjacent transmission beams have different orthogonal polarizations (S1320).

[0191] When a pair of transmit polarization components corresponding to the first orthogonal polarization are radiated onto a transmit antenna element having the first orthogonal polarization, a transmit beam having the first orthogonal polarization can be formed (i.e., no polarization combining occurs). When a pair of transmit polarization components corresponding to the second orthogonal polarization are radiated onto a transmit antenna element having the first orthogonal polarization, a transmit beam having the second orthogonal polarization can be formed based on polarization combining.

[0192] In order to correct the deviation in amplitude and phase characteristics between the pair of transmission paths corresponding to the pair of transmission channels associated with each transmission beam, the multi-beam antenna device can adjust the amplitude and phase of the pair of transmission polarization components (S1330).

[0193] Correction for deviations in amplitude and phase characteristics between transmission paths is only performed when the transmitted beam has orthogonal polarization characteristics different from those of the transmitted antenna elements, based on polarization synthesis. That is, when the orthogonal polarization of the assigned transmitted beam differs from that of the associated transmitted antenna element, the multi-beam antenna device can adjust the amplitude and phase of a pair of transmitted polarization components to correct for deviations in amplitude and phase characteristics between a pair of transmission paths associated with the assigned transmitted beam. Furthermore, when the orthogonal polarization of the assigned transmitted beam is the same as that of the associated transmitted antenna element, the multi-beam antenna device may not correct for deviations in amplitude and phase characteristics between a pair of transmission paths associated with the assigned transmitted beam.

[0194] In order to correct for the deviation in amplitude and phase characteristics between a pair of receiving paths corresponding to a pair of receiving channels associated with each receiving beam, the multi-beam antenna device can adjust the amplitude and phase of a pair of received signals output from a pair of receiving paths (S1340).

[0195] Correction for amplitude and phase characteristic deviations between receiving paths is performed only on a pair of received signals input to a receiving antenna element having orthogonal polarization characteristics different from the orthogonal polarization of the corresponding transmitted beam (thus requiring channel non-reciprocity correction). Therefore, when the orthogonal polarization characteristics of the receiving antenna element associated with the assigned receiving beam differ from the orthogonal polarization of the transmitted beam formed in the same spatial direction, the multi-beam antenna device can adjust the amplitude and phase of a pair of received signals to correct for amplitude and phase characteristic deviations between the pair of receiving paths associated with the assigned receiving beam. Furthermore, when the orthogonal polarization characteristics of the receiving antenna element associated with the assigned receiving beam are the same as the orthogonal polarization of the transmitted beam formed in the same spatial direction, the multi-beam antenna device may not perform correction for amplitude and phase characteristic deviations between the pair of receiving paths associated with the assigned receiving beam.

[0196] The multi-beam antenna device can perform channel non-reciprocity correction (S1350) on the received signals corresponding to a pair of received channels associated with each received beam.

[0197] In some embodiments, as part of performing channel non-reciprocity correction (S1350), the multi-beam antenna device can generate polarization conversion signals from the received signals corresponding to a pair of received channels associated with each received beam; the polarization conversion signals correspond to the orthogonal polarization of the transmitted beams formed in the same spatial direction by each received beam. Specifically, the multi-beam antenna device can polarize a pair of received signals input to a received antenna element having orthogonal polarization characteristics different from the orthogonal polarization of the corresponding transmitted beam (therefore requiring channel non-reciprocity correction), and output a pair of received polarization components corresponding to the orthogonal polarization of the transmitted beams formed in the same spatial direction.

[0198] In other embodiments, as part of performing channel non-reciprocity correction (S1350), the multi-beam antenna device can generate multiple receiving polarization components based on the received signals corresponding to a pair of receiving channels associated with each receiving beam. Furthermore, the multi-beam antenna device can output a pair of receiving polarization components corresponding to the orthogonal polarization of the transmit beams formed in the same spatial direction among the multiple receiving polarization components to a pair of receiving channels associated with each receiving beam.

[0199] The above description is merely illustrative of the technical concept of this embodiment. For those skilled in the art, various modifications and variations can be made without departing from the essential characteristics of this embodiment. Therefore, this embodiment is not intended to limit the technical concept but is for illustrative purposes, and the scope of the technical concept is not limited by the described embodiment. The scope of protection of this embodiment should be interpreted based on the appended claims, and all technical concepts within the equivalent scope should be interpreted as falling within the scope of the rights of this embodiment.

[0200] [Cross-references to related applications]

[0201] This application claims priority to Korean Patent Application No. 10-2020-0145879 filed on November 4, 2020 and Korean Patent Application No. 10-2021-0150406 filed on November 4, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. A method performed by a multi-beam antenna device utilizing two dual orthogonal polarizations, the multi-beam antenna device having an array antenna including a transmitting antenna element for forming multiple transmitting beams and a receiving antenna element for forming multiple receiving beams, the transmitting antenna element being a dual orthogonal polarization antenna element, the receiving antenna element being a dual orthogonal polarization antenna element, the transmitting antenna element and the receiving antenna element having different dual orthogonal polarization characteristics, the method comprising the following steps: Multiple transmission polarization components are generated from the transmission signals corresponding to a pair of transmission channels associated with each transmission beam; For a pair of transmission channels associated with each transmission beam, output a pair of transmission polarization components that correspond to the first dual orthogonal polarization or a pair of transmission polarization components that correspond to the second dual orthogonal polarization, so that spatially adjacent transmission beams have different dual orthogonal polarizations. Multiple receiving polarization components are generated from the received signals corresponding to a pair of receiving channels associated with each receiving beam; as well as From the plurality of receiving polarization components, a pair of receiving polarization components corresponding to the dual orthogonal polarizations of the transmit beams formed in the same spatial direction are output to a pair of receiving channels associated with each receiving beam.

2. The method as described in claim 1, wherein, When a pair of transmit polarization components corresponding to the first dual orthogonal polarization are emitted onto the transmit antenna element having the first dual orthogonal polarization, a transmit beam having the first dual orthogonal polarization is formed. When a pair of transmit polarization components corresponding to the second dual orthogonal polarization are transmitted to the transmit antenna element having the first dual orthogonal polarization, a transmit beam having the second dual orthogonal polarization based on polarization synthesis is formed.

3. The method as described in claim 1, wherein, The method further includes adjusting the amplitude and phase of the pair of transmit polarization components to correct for deviations in amplitude and phase characteristics between a pair of transmit paths associated with each transmit beam.

4. The method of claim 1, wherein, The method includes adjusting the amplitude and phase of a pair of transmit polarization components to correct for deviations in amplitude and phase characteristics between a pair of transmit paths associated with the assigned transmit beam when the dual orthogonal polarization of the assigned transmit beam differs from the dual orthogonal polarization characteristics of the associated transmit antenna element.

5. The method of claim 1, wherein, The method further includes adjusting the amplitude and phase of the pair of receiving polarization components to correct for deviations in amplitude and phase characteristics between a pair of receiving paths associated with each receiving beam.

6. The method of claim 1, wherein, The method further includes adjusting the amplitude and phase of a pair of received signals to correct for deviations in amplitude and phase characteristics between a pair of received paths associated with the assigned received beam when the dual orthogonal polarization characteristics of the received antenna element associated with the assigned received beam differ from the dual orthogonal polarization of the transmitted beam formed in the same spatial direction.

7. A multi-beam antenna device utilizing two dual orthogonal polarizations, the device comprising: An array antenna includes a transmitting antenna element for forming multiple transmitting beams and a receiving antenna element for forming multiple receiving beams. The transmitting antenna element is a dual orthogonal polarization element, and the receiving antenna element is a dual orthogonal polarization element. The transmitting antenna element and the receiving antenna element have different dual orthogonal polarization characteristics. The transmit polarization combining unit generates multiple transmit polarization components from the transmit signals corresponding to a pair of transmit channels associated with each transmit beam; The transmit polarization allocation unit outputs a pair of transmit polarization components corresponding to the first dual orthogonal polarization or a pair of transmit polarization components corresponding to the second dual orthogonal polarization among the plurality of transmit polarization components to a pair of transmit channels associated with each transmit beam, so that spatially adjacent transmit beams have different dual orthogonal polarizations. The receiving polarization combining unit generates multiple receiving polarization components from the received signals corresponding to a pair of receiving channels associated with each receiving beam; as well as The receiving polarization allocation unit outputs a pair of receiving polarization components corresponding to the dual orthogonal polarizations of the transmitted beams formed in the same spatial direction from the plurality of receiving polarization components to a pair of receiving channels associated with each receiving beam.

8. The multi-beam antenna device as described in claim 7, wherein, When a pair of transmit polarization components corresponding to the first dual orthogonal polarization are emitted onto the transmit antenna element having the first dual orthogonal polarization, a transmit beam having the first dual orthogonal polarization is formed. When a pair of transmit polarization components corresponding to the second dual orthogonal polarization are transmitted to the transmit antenna element having the first dual orthogonal polarization, a transmit beam having the second dual orthogonal polarization based on polarization synthesis is formed.

9. The multi-beam antenna device as described in claim 7, wherein, Further includes: Multiple transmit RF chains for forming multiple transmit paths corresponding to the multiple transmit channels and multiple receive RF chains for forming multiple receive paths corresponding to the multiple receive channels; and An amplitude and phase correction unit adjusts the amplitude and phase of the pair of transmit polarization components to correct deviations in amplitude and phase characteristics between a pair of transmit paths associated with each transmit beam, and adjusts the amplitude and phase of the pair of receive signals to correct deviations in amplitude and phase characteristics between a pair of receive paths associated with each receive beam.

10. The multi-beam antenna device as claimed in claim 9, wherein, The amplitude and phase correction unit is configured to, When the dual orthogonal polarization of the assigned transmit beam differs from the dual orthogonal polarization characteristics of the associated transmit antenna element, the amplitude and phase of a pair of transmit polarization components are adjusted to correct the deviation in amplitude and phase characteristics between a pair of transmit paths associated with the assigned transmit beam.

11. The multi-beam antenna device as claimed in claim 9, wherein, The amplitude and phase correction unit is configured to, When the dual orthogonal polarization characteristics of the receiving antenna element associated with the assigned receiving beam differ from the dual orthogonal polarization of the transmitting beam formed in the same spatial direction, the amplitude and phase of a pair of received signals are adjusted to correct the deviation in amplitude and phase characteristics between a pair of receiving paths associated with the assigned receiving beam.

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