Wireless communication device and wireless communication method

Abstract

To perform an uplink calibration (UL CAL) operation regardless of the arrival of delayed radiated signals from other wireless communication devices.SOLUTION: A wireless communication device 100A includes m transmitters (TX) 311-1 to 311-m, m receivers (RX) 312-1 to 312-m, a calibration transceiver (CAL-TRX) 51, and a control unit 22 that controls a UL CAL operation that transmits a UL CAL signal from the CAL-TRX 51 to each of the m RXs 312-n. The wireless communication device 100A performs a TDD operation. The control unit 22 controls each of the m TXs 311-n to perform a UL CAL operation in a predetermined time period before a downlink slot (DL Slot) in which the TXs 311-n transmit a downlink (DL) signal.SELECTED DRAWING: Figure 16

Description

[Technical field]

[0001] The present disclosure relates to a wireless communication device and a wireless communication method. [Background technology]

[0002] In the 5th generation (5G) mobile communications, the operation below 6GHz (Sub6GHz band) is attracting attention because it enables wide-area propagation and transmission suitable for mobile communications. In addition, traffic continues to grow at an annual rate of 1.3 times, and it is necessary to respond to such traffic demand. However, there are frequency circumstances in which it is not easy to secure frequency bandwidth below Sub6GHz. In light of this background, it is considered effective to use an active antenna system (AAS) that employs a full digital beamforming method as a base station and apply spatial multiplexing and massive MIMO (multiple input multiple output) by AAS. For this reason, commercialization of AAS is being promoted both domestically and overseas. In addition, in order to realize the 5G System that supports Beyond 5G / 6G, which is expected to be introduced in 2030, it will become increasingly necessary to deploy AAS in a wide area.

[0003] Accordingly, the spatial multiplexing performance of AAS will become even more important in the future. In AAS, the degradation of the signal-to-interference-plus-noise ratio (SINR) of DL (DownLink) signals at high output power is determined by the radiation of nonlinear distortion signals radiated in the same direction as the desired signal to the desired terminal. Therefore, in order to improve the radiation of the above-mentioned nonlinear distortion, AAS is equipped with a function that performs distortion compensation using DPD (Digital Pre-distortion) for DL ​​signals transmitted from all transmitters within the AAS. In this way, AAS significantly improves spatial multiplexing performance in the high output range by implementing both the improvement of nonlinear distortion and full digital beamforming.

[0004] In addition, in the AAS, in order to maintain and ensure null depth (realization of spatial orthogonality) toward terminals other than the desired terminal, DL CAL (Calibration) operation is performed to match the amplitude and phase characteristics among multiple transmitters in the AAS, and UL (Uplink) CAL operation is performed to match the amplitude and phase characteristics among multiple receivers in the AAS. Specifically, in the DL CAL operation, a DL calibration weight (DL CAL Weight) is calculated to compensate for the variation in the amplitude and phase characteristics among multiple transmitters, and in the UL CAL operation, a UL calibration weight (UL CAL Weight) is calculated to compensate for the variation in the amplitude and phase characteristics among multiple receivers.

[0005] In AAS, after the SINR of DL signal is improved by DPD and when the output power is low, the impact of DL / UL CAL accuracy becomes dominant in determining the SINR of DL signal. Therefore, it is important to implement dual compensation of DL / UL CAL and DPD in AAS to realize high SINR of DL signal and large transmission capacity with high cell throughput.

[0006] The configuration of the AAS 900 according to the related art, and the DPD operation and DL / UL CAL operation in the AAS 900 according to the related art will be described below. First, an example of a circuit configuration of an AAS900 according to the related art will be described with reference to Fig. 1. It is assumed in Fig. 1 that the AAS900 is used as a base station. In Fig. 1, the AAS900 is described as having 32 antennas 41-1 to 41-32, which will be described later, but the number of antennas provided in the AAS900 is not limited to this and may be any number as long as it is plural.

[0007] As shown in FIG. 1, the AAS 900 of the related art includes an optical transceiver 10, a baseband (BB) unit 20, a frontend (FE) unit 30, 32 antennas 41-1 to 41-32, a calibration transceiver (CAL-TRX) 51, a switch (SW) 52, and a calibration network (CAL Network) 60.

[0008] The BB unit 20 also includes 32 DPD units 21-1 to 21-32 corresponding to the 32 antennas 41-1 to 41-32, respectively. The FE unit 30 also includes 32 transceivers (TRX) 31-1 to 31-32, 32 transmitting amplifiers 32-1 to 32-32, 32 receiving amplifiers 33-1 to 33-32, 32 couplers 34-1 to 34-32, 32 SWs 35-1 to 35-32, and 32 band-pass filters (BPFs) 36-1 to 36-32 corresponding to the 32 antennas 41-1 to 41-32, respectively.

[0009] In the following, when it is not necessary to specify which antennas 41-1 to 41-32 they are, they will be referred to as antennas 41-n (n=1,...,32). Similarly, the DPD units 21-1 to 21-32, TRXs 31-1 to 31-32, transmitting amplifiers 32-1 to 32-32, receiving amplifiers 33-1 to 33-32, couplers 34-1 to 34-32, SWs 35-1 to 35-32, and BPFs 36-1 to 36-32 will be referred to as DPD unit 21-n, TRX 31-n, transmitting amplifier 32-n, receiving amplifier 33-n, coupler 34-n, SWs 35-n, and BPFs 36-n, respectively.

[0010] The optical transceiver 10 performs optical-electrical conversion of signals transmitted and received between a distribution unit (DU) 200 and the BB section 20, and vice versa.

[0011] When performing a DL CAL operation, the BB unit 20 outputs a DL CAL signal to each TRX 31-n in the FE unit 30. When performing a UL CAL operation, the BB unit 20 outputs a UL CAL signal to the CAL-TRX 51.

[0012] Furthermore, when performing DL operation, the BB unit 20 outputs a DL signal (e.g., a BF (Beam Forming) signal) output from the optical transceiver 10 to each TRX 31-n in the FE unit 30. When performing UL operation, the BB unit 20 outputs a UL signal output from each TRX 31-n in the FE unit 30 to the optical transceiver 10.

[0013] As described above, the BB unit 20 includes 32 DPD units 21-n. The DPD unit 21-n receives a signal that has passed through the transmission amplifier 32-n as feedback from the coupler 34-n. The DPD unit 21-n uses the feedback signal to perform distortion compensation by DPD on the signal (DL signal or DL ​​CAL signal) that passes through the transmission amplifier 32-n.

[0014] As described above, the FE section 30 includes 32 TRXs 31-n, 32 transmitting amplifiers 32-n, 32 receiving amplifiers 33-n, 32 couplers 34-n, 32 SWs 35-n, and 32 BPFs 36-n.

[0015] The TRX31-n includes a transmitter (TX) and a receiver (RX), both of which are not shown. Hereinafter, the TX in the TRX31-n will be referred to as the TX311-n, and the RX in the TRX31-n will be referred to as the RX312-n. The TX311-n converts the signal (DL signal or DL ​​CAL signal) output from the BB unit 20 from an IQ (In-phase and Quadrature) signal to an RF (Radio Frequency) signal, and outputs the signal to the transmission amplifier 32-n. The RX312-n also converts the signal (UL signal or UL CAL signal) output from the reception amplifier 33-n from an RF signal to an IQ signal, and outputs the signal to the BB unit 20.

[0016] The transmission amplifier 32-n amplifies the signal (DL signal or DL ​​CAL signal) output from the TX 311-n in the TRX 31-n, and outputs the amplified signal to the SW 35-n. The coupler 34-n feeds back the signal that has passed through the transmission amplifier 32-n to the DPD unit 21-n in the BB unit 20 via the RX 312-n in the TRX 31-n. The receiving amplifier 33-n amplifies the signal (UL signal or UL CAL signal) output from the SW35-n, and outputs the amplified signal to the RX312-n in the TRX31-n.

[0017] SW35-n is a switch that switches the connection between TRX31-n and the antenna 41-n and the CAL Network 60. When performing DL CAL operation, SW35-n outputs the DL CAL signal output from the transmitting amplifier 32-n to the CAL Network 60. When performing UL CAL operation, SW35-n outputs the UL CAL signal output from the CAL Network 60 to the receiving amplifier 33-n. When performing DL operation, SW35-n outputs the DL signal output from the transmitting amplifier 32-n to the antenna 41-n. When performing UL operation, SW35-n outputs the UL signal output from the antenna 41-n to the receiving amplifier 33-n.

[0018] The BPF 36-n passes only signals in a predetermined frequency band among signals transmitted and received between the TRX 31-n and the antenna 41-n and the CAL Network 60.

[0019] When performing DL CAL operation, the CAL Network 60 combines the DL CAL signals output from each SW35-n and outputs the combined signal to the SW52. When performing UL CAL operation, the CAL Network 60 distributes the UL CAL signal output from the SW52 and outputs the distributed signal to each SW35-n.

[0020] The SW52 is a switch that switches the connection between the CAL-TRX51 and the CAL Network 60. When performing a DL CAL operation, the SW52 outputs a DL CAL signal output from the CAL Network 60 to the CAL-TRX51. When performing a UL CAL operation, the SW52 outputs a UL CAL signal output from the CAL-TRX51 to the CAL Network 60.

[0021] The CAL-TRX51 includes a calibration transmitter (CAL-TX) and a calibration receiver (CAL-RX), both of which are not shown. Hereinafter, the CAL-TX in the CAL-TRX51 will be referred to as CAL-TX511, and the CAL-RX in the CAL-TRX51 will be referred to as CAL-RX512. When performing a DL CAL operation, the CAL-RX512 converts the DL CAL signal output from the SW52 from an RF signal to an IQ signal and sends it to the BB unit 20. When performing a UL CAL operation, the CAL-TX511 converts the UL CAL signal output from the BB unit 20 from an IQ signal to an RF signal and outputs it to the SW52.

[0022] When performing DL CAL operation, the BB unit 20 calculates the DL CAL Weight of each TX 311-n based on the DL CAL signal output from the CAL-RX 512. When performing UL CAL operation, the BB unit 20 calculates the UL CAL Weight of each RX 312-n based on the UL CAL signal output from each RX 312-n.

[0023] When performing DL operation, the antenna 41-n transmits the DL signal output from the SW35-n to a UE (User Equipment) (not shown). When performing UL operation, the antenna 41 receives a UL signal from the UE and outputs it to the SW35-n.

[0024] The following describes an outline of the operation of the AAS 900 according to the related art. First, an example of a DL CAL operation and a DPD operation of the AAS 900 according to the related art will be described with reference to FIG. As shown in FIG. 2, the BB unit 20 outputs a DL CAL signal to each TX 311-n in each TRX 31-n. Each TX 311-n converts the DL CAL signal from an IQ signal to an RF signal and outputs it. The DL CAL signal output from each TX 311-n is amplified by each transmission amplifier 32-n and then output to the CAL Network 60. At this time, each coupler 34-n feeds back the DL CAL signal that has passed through the transmission amplifier 32-n to the DPD unit 21-n in the BB unit 20. Each DPD unit 21-n uses the fed back signal to perform distortion compensation by DPD on the DL CAL signal that subsequently passes through the transmission amplifier 32-n. In addition, as the DL CAL signal output to the CAL Network 60, all DL CAL signals output from each of the multiple TXs 311-n are frequency multiplexed. As a result, even if the DL CAL signals output from each TX311-n are combined in the CAL Network 60, the frequency allocation of each sub carrier constituting the DL CAL signal made of OFDM is determined in advance so that they do not overlap in frequency. As a result, the first DL CAL signal allocation and transmission method is a case where DL CAL signals from all TX311-n are transmitted to CAL-RX512 in one DL CAL period. As another transmission method, DL CAL signals are transmitted and received for each frame by one TX311-n. In other words, the second DL CAL signal allocation and transmission method is a case where DL CAL signals that overlap in frequency from each TX311-n or DL ​​CAL signals with a completely common frequency allocation are transmitted and received by time division multiplexing sequentially while switching the TX311-n that is the DL CAL target. Therefore, in the case of the latter second DL CAL signal arrangement / transmission method, the DL CAL signal passes through CAL Network 60 only for one TX 311-n, so DL CAL transmission / reception is repeated for the number of TX 311-n. However, in either of the above two DL CAL signal arrangement / transmission methods, the signal passes through CAL Network 60 from each TX 311-n, and is then transmitted to CAL-RX 512 in CAL-TRX 51 via SW 52.The CAL-RX 512 converts the DL CAL signal transmitted from the CAL Network 60 from an RF signal to an IQ signal, and outputs the IQ signal to the BB unit 20.

[0025] In the case of the first DL CAL signal arrangement and transmission method described above, the DL CAL signals between each TX311-n are multiplexed in an uncorrelated and orthogonal frequency arrangement. In this case, the DL CAL signals output from each TX311-n in each TRX31-n are frequency-multiplexed and combined in the CAL-RX512 after passing through the CAL Network60. Therefore, as in the case of the first DL CAL signal arrangement and transmission method, when the DL CAL signals are frequency-multiplexed and received simultaneously in the CAL-RX512, the BB unit 20 separates and extracts the DL CAL signals output from the CAL-RX512 into DL CAL signals for each TX311-n again, and then calculates the DL CAL Weight. However, in the case of the second DL CAL signal arrangement and transmission method described above, the transmission and reception of the DL CAL signal is performed for each TX311-n for each Frame. That is, DL CAL signals that overlap in frequency from each TX 311-n or DL ​​CAL signals that have a completely common frequency allocation are time-division multiplexed sequentially while switching the DL CAL target TX 311-n, and received multiple times by CAL-RX 512. In the case of this second DL CAL signal allocation and transmission method, the DL CAL Weight is calculated individually and multiple times sequentially for each TX 311-n for the DL CAL signal that is output from each TX 311-n and passes through CAL Network 60.

[0026] Here, the DL CAL Weight of TX311-n is the product of the amplitude and phase characteristic [TX#n] of TX311-n and the amplitude and phase characteristic [CAL-RX] of CAL-RX512, as expressed in the following formula 1.

number

[0027] Next, an example of DL operation and DPD operation of the AAS 900 according to the related art will be described with reference to FIG. As shown in FIG. 3, the BF signal transmitted from the DU 200 is input to the BB unit 20 via the optical transceiver 10. The BB unit 20 corrects the BF signal using the DL CAL Weight of each TX 311-n in each TRX 31. Specifically, the BB unit 20 multiplies the BF signal by a fraction having the DL CAL Weight as the denominator and the fixed amplitude-phase characteristic [CAL-RX (fixed)] of the CAL-RX 512 as the numerator. The corrected BF signal is expressed as in the following formula 2. Note that [CAL-RX (fixed)] is either a value obtained by measuring the AAS individually during a test process during production in a factory, or a fixed value determined as a design specification, which is stored in advance in the BB unit 20.

number

[0028] The BF signal corrected by the BB unit 20 is converted from an IQ signal to an RF signal in each TX 311-n, amplified in each transmission amplifier 32-n, and then output from the FE unit 30 to each antenna 41-n. At this time, each coupler 34-n feeds back the BF signal that has passed through the transmission amplifier 32-n to the DPD unit 21-n in the BB unit 20. Each DPD unit 21-n uses the fed back signal to perform distortion compensation by DPD on the BF signal that subsequently passes through the transmission amplifier 32-n. However, when DPD and DL CAL are operated together according to the nonlinear characteristics of the AMP, in the case of an AMP that can ensure linearity at low input / output, the level of the DL CAL signal is set in advance to a DPD On threshold. As a result, while sequentially detecting transmission signals including DL CAL signals below the threshold, nonlinearity in the high input / output range is compensated for by DPD, and in the low input / output range with good linearity, compensation is applied to match the variations in the amplitude-phase-frequency characteristics of each TX 311-n with DL CAL. However, the degree of nonlinearity of the AMP in the low input / output range also shows a different AM-AM and AM-PM aspect from that in the high input / output range. Therefore, when the linearity is poor, the order may be to first linearize the wide dynamic range of the AMP from low input / output to high input / output by DPD, and then perform DL CAL compensation after linearization in the entire input / output range by DPD.

[0029] Here, the BF signal output from the FE unit 30 to each antenna 41-n passes through each TX 311-n, and is therefore expressed by the following Equation 3.

number

[0030] Moreover, when [TX#n] is deleted from Equation 3, it is expressed as Equation 4 below.

number

[0031] Next, an example of the UL CAL operation of the AAS 900 according to the related art will be described with reference to FIG. 4, the BB unit 20 outputs a UL CAL signal to the CAL-TX 511 in the CAL-TRX 51. The CAL-TX 511 converts the UL CAL signal from an IQ signal to an RF signal and outputs it. The UL CAL signal output from the CAL-TX 511 is distributed by the CAL Network 60 to each RX 312-n.

[0032] The UL CAL signal distributed by the CAL Network 60 is amplified by each receiving amplifier 33-n, then converted from an RF signal to an IQ signal by each RX 312-n in each TRX 31, and output from the FE unit 30 to the BB unit 20.

[0033] The BB unit 20 calculates the UL CAL Weight for each RX 312-n based on the UL CAL signal output from each RX 312-n. Note that, unlike the DL CAL signal, the UL CAL Weight can be calculated for each RX 312-n even if it is the same UL CAL signal after the UL CAL signal is distributed to each RX 312-n by the CAL Network 60. Therefore, for the UL CAL, the UL CAL Weights of all RX 312-n can be calculated at once using the same UL CAL signal for each RX 312-n.

[0034] Here, the UL CAL Weight of RX312-n is the product of the amplitude and phase characteristic [RX#n] of RX312-n and the amplitude and phase characteristic [CAL-TX] of CAL-TX 511, as expressed in the following equation 5.

number

[0035] Next, an example of UL operation of the AAS 900 according to the related art will be described with reference to FIG. 5, each antenna 41-n receives and outputs a UL signal, which is a UL Ch estimation wave, from the UE. The UL signal output from each antenna 41-n is amplified by each receiving amplifier 33-n, and then converted from an RF signal to an IQ signal by each RX 312-n in each TRX 31, and output from the FE unit 30 to the BB unit 20. The UL signal output from the FE unit 30 passes through each RX 312-n, and is therefore expressed by the following Equation 6.

number

[0036] The BB unit 20 corrects the UL signal using the UL CAL Weight of each RX 312-n. Specifically, the BB unit 20 multiplies the UL signal by a fraction whose denominator is the UL CAL Weight and whose numerator is the fixed amplitude-phase characteristic [CAL-TX (fixed)] of the CAL-TX 511. The UL signal after correction is expressed as in the following formula 7. Note that [CAL-TX (fixed)] is either a value obtained by measuring each AAS individually during the test process during production in the factory or a fixed value determined as a design specification, which is stored in advance in the BB unit 20.

number

[0037] Moreover, when [RX#n] is deleted from Equation 7, it is expressed as Equation 8 below.

number

[0038] Next, the timing at which the AAS 900 according to the related art executes a DL CAL operation and a UL CAL operation will be described with reference to FIG. In FIG. 6, it is assumed that the AAS900 according to the related art performs TDD (Time Division Duplex) operation. TDD operation is an operation in which the same frequency is used for UL and DL, and DL operation and UL operation are switched over time for transmission and reception. DL operation is performed in the DL slot, and UL operation is performed in the UL slot. A flexible slot is provided in the section switching from the DL slot to the UL slot. The flexible slot includes a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS). The DwPTS is a section reserved for DL ​​operation. The UpPTS is a section reserved for UL operation. The GP is a section in which neither DL operation nor UL operation is performed.

[0039] 6 also shows, from the top, the DL timing of the AAS 900, the On / Off status of the TX 311-n of the AAS 900, the UL timing of the AAS 900, and the On / Off status of the RX 312-n of the AAS 900, with respect to the AAS 900. Furthermore, with respect to the UE communicating with the AAS 900, Fig. 6 also shows, from the top, the DL timing of the UE, the On / Off status of the UE receiver (RX), the UL timing of the UE, and the On / Off status of the UE transmitter (TX).

[0040] As shown in FIG. 6, the AAS900 according to the related art may perform CAL in a DL / UL CAL Sequence specification in which a DL CAL operation (i.e., an operation of transmitting a DL CAL signal from each TX311-n to CAL-RX512) is performed during the GP time period in the Flexible Slot after the DL Slot and during the Tx Off Transient period (10 μsec in the 3GPP (registered trademark) (3rd Generation Partnership Project) standard for 5G), which is the time period for switching TX311-n from On to Off, and then a UL CAL operation (i.e., an operation of transmitting a UL CAL signal from CAL-TX511 to each RX312-n). In addition to this case, the DL CAL signal arrangement between each TX311-n may be frequency multiplexed for each frame (for example, 2.5 msec / 5 slot period in the above European region 1, or 5 msec / 10 slot period in the example of European region 2) determined by the TDD DL / UL configuration of the repetition period of each DL / UL configuration (when DL Slot: D, Flexible Slot: F, UL Slot: U, as an example, when Sub Carrier Spacing = 30 kHz, "DDDFU" is TDD operation repeated at 2.5 msec period / 1 frame). Alternatively, a common DL CAL signal or a DL CAL signal with frequency overlap may be transmitted sequentially from each TX311-n. In both of these cases, there are cases where the CAL specification alternates between frames in which only DL CAL signals are allocated for the entire 10 μsec time period of the Tx Off Transient period to perform DL CAL, and frames in which only UL CAL signals are allocated to perform UL CAL (as mentioned above, UL CAL is performed by sending and receiving a completely common UL CAL signal collectively to all RX312-n). Note that there are also cases where UL CAL operation is performed beyond the Tx Off Transient period and into GP. However, in this case, the TX Off Power Limit specified by 3GPP must be less than -83 dBm / MHz.Therefore, although UL CAL is performed by significantly lowering the level of the UL CAL signal passing through the antenna 41-n, the level of the UL CAL signal passing through the antenna 41-n must comply with the TX Off Power Limit: -83 dBm / MHz or less. In this case, since the SINR of the UL SINR is further reduced, in order to secure the desired UL CAL SINR, an averaging process is also performed to improve the SINR after receiving the UL CAL signal to the desired value by 20Log(N)-10Log(N)=10Log(N) when the number of averaging times is N. Note that, as a technique for performing a DL CAL operation during a GP time period in a flexible slot and then performing a UL CAL operation, the technique described in Patent Document 1 can be given. [Prior art documents] [Patent documents]

[0041] [Patent Document 1] JP 2019-216366 A Summary of the Invention [Problem to be solved by the invention]

[0042] As described above, the AAS 900 according to the related art performs DL CAL operation during the Tx Off Transient period in the GP in the flexible slot after the DL slot, and then performs UL CAL operation. The following describes the problems with this operation.

[0043] For example, assume that there are multiple AASs of an operator other than AAS900 located far away (several kilometers apart) that perform TDD operation in a frequency band different from that of AAS900 and included in the passband of BPF36-n of AAS900.

[0044] In this case, DL delayed radiation signals (with delays of several tens of usec) according to the distance from multiple AASs of another operator arrive at the AAS 900. Therefore, these DL delayed radiation signals interfere with the DL CAL signal and UL CAL signal that the AAS 900 transmits and receives during the Tx Off Transient period.

[0045] For example, in the example in the upper part of Fig. 7, the AAS of Operator A transmits and receives DL CAL signals and UL CAL signals in frequency band a during the Tx Off Transient period. However, frequency band b of the AAS of Operator B and frequency band c of the AAS of Operator C are adjacent to frequency band a and are included in the passband of the RF BPF of the AAS of Operator A. In particular, when the AAS of Operator A shares the RAN with Operators B and C, the passband of the RF BPF needs to cover all operator frequency bands. For this reason, the RF BPF specifications are such that it is not possible to suppress transmission waves from operators other than Operator A. Therefore, DL delayed radiation signals from the AASs of Operators B and C interfere with the DL CAL signals and UL CAL signals transmitted and received by the AAS of Operator A in terms of time.

[0046] Also, in the example at the bottom of Fig. 7, the AAS of Operator D transmits and receives DL CAL signals and UL CAL signals in the frequency band during the Tx Off Transient period. However, the frequency band e of the AAS of Operator E is included in the passband of the RF BPF of the AAS of Operator D. Therefore, the DL delayed radiation signal from the AAS of Operator E interferes in time with the DL CAL signal and UL CAL signal transmitted and received by the AAS of Operator D.

[0047] However, for DL ​​CAL signals, if they are transmitted from each TX 311-n to CAL-RX 512 within 10 μsec of the TX Off Transient Term, and the Spurious standards of 3GPP and local radio wave laws are observed, the transmission amplifier 32-n can raise the level to the maximum rated output level equivalent to the operating DL transmission wave. In this way, if the DL CAL signal is transmitted at a high level and in a high SINR state, the DL CAL signal will not be affected by interference from DL delayed radiation signals.

[0048] On the other hand, the UL CAL signal is transmitted from the CAL-TX511, but since it does not pass through an amplifier, the level cannot be increased. In addition, when the UL CAL operation is performed beyond the Tx Off Transient period and goes into the GP, each TX311-n must comply with the TX Off Power Limit (-83 dBm / MHz) or less, so it is necessary to prevent unnecessary radiation from the antenna 41-n. In addition, the reception level of the UL CAL signal transmitted from the CAL-TX511 to each RX312-n and received at the input terminal of each receiving amplifier 33-n must be improved by DPD to improve the nonlinearity caused by the AMP of the transmitted wave of the UL CAL signal itself, which occurs when a transmitting AMP that can increase the UL CAL level to the same level as the DL CAL level is inserted. Therefore, an AMP and DPD that are undesirable from the viewpoint of UL CAL are required, and even if the nonlinear distortion is compensated for by DPD, the adverse effect of the remaining AM-AM / AM-PM nonlinear distortion on the UL CAL accuracy cannot be ignored. Therefore, without providing a transmit AMP and DPD, the UL CAL level is reduced by approximately -3 dB of power distribution for each branch of the UL CAL signal in the CAL Network 60 at 1:n. Therefore, the UL CAL signal level input to each RX312-n becomes extremely low. In addition, the UL CAL signal level to each RX312-n varies due to differences in the length of the wiring in the CAL Network 60, which is the path through which the UL CAL signal passes from the CAL-TX511 to each RX312-n. Therefore, the AAS900 increases the number of repetitions N of the UL CAL operation to ensure the desired UL CAL SINR, and also improves the SINR after receiving the UL CAL signal to the desired value by 20Log(N)-10Log(N)=10Log(N) by averaging processing, assuming the number of averaging times = N.

[0049] In addition, when the frequency band of the AAS of another operator is included in the passband of the BPF 36-n of the AAS900, the DL delayed radiation signal from the AAS of another operator or the antenna-separated base station is also received at the input end of each receiving amplifier 33-n via the antenna 41-n, the BPF 36-n, and the SW 35-n. At this time, the reception level of the DL delayed radiation signal at the input end of each receiving amplifier 33-n exceeds the reception level of the UL CAL signal, so that the UL CAL signal may be significantly interfered with by the DL delayed radiation signal. At this time, the reception system saturation may occur in the reception system rear circuit including the receiving amplifier 33-n due to the DL delayed radiation signal that causes delayed interference. When reception clipping distortion occurs due to reception saturation of the reception system rear circuit including the receiving amplifier 33-n, the frequency spectrum splash component due to the reception clipping distortion spreads at once into the frequency band used by the AAS900 for transmission and reception in TDD operation, causing destructive interference.

[0050] With reference to FIG. 8, an example of frequency spectrum splash caused by DL delayed radiation signal will be described. (a) and (b) of FIG. 8 show the characteristics of the received power at the input terminal of the receiving amplifier 33-n, where the horizontal axis shows time and the vertical axis shows the power level of the received power. In this test, the transmission and reception operation of the AAS to be tested was experimentally set to continuous reception only in all slots in the outdoor environment of the current station. In addition, with this setting, we focused on Symbol #9 (the last 10th DL symbol because of the zero-origin symbol number) which is the last DL symbol of the last DL slot in the frame (DwPTS: DL 10 symbols, GP: 2 symbols, UpPTS: 2 symbols in the flexible slot located between DL and UL in the TDD DL / UL configuration of "DDDFU") and the first Symbol #10 of the GP 2 symbols including the following TX Off Transient period of 10 μsec. For this reason, in (a) and (b) of FIG. 8, the horizontal axis (time) vs. the vertical axis (reception level) of Symbol #9 and Symbol #10, which includes a TX Off Transient period of 10 μsec, are deformed and enclosed in a thick-line rectangle for easy understanding.

[0051] As shown by arrow Z, the DL signal with delay (occurring according to the distance from the AAS) from the band of another Operator B in Figure 7 in Figure 8(b) interferes with the UL CAL signal section of the band of Operator A in Figure 7 in Figure 8(a), and the AAS reception saturation level is exceeded. This causes AAS reception saturation, and spectrum splash with frequency spreading due to hard clipping distortion occurs. As a result, splash interference occurs in the UL CAL signal in the band of Operator A adjacent to the band of Operator C, as shown in Figure 8(c) and (d), and the SINR of the DL CAL signal deteriorates significantly. This deterioration causes the amplitude and phase variation between each RX due to UL CAL failure to increase, so a CAL Alarm is issued, and if the number of CAL Alarms exceeds the specified number, beamforming failure occurs, leading to the AAS stopping operation.

[0052] Also, as mentioned above, Symbol #9 indicates the last DL Symbol in the last DL slot of DwPTS in the flexible slot between DL and UL, and Symbol #10 is the first symbol in the following GP, and indicates a symbol including a Tx Off Transient period for performing UL CAL operation. In addition, in both (a) and (b) of FIG. 8, during the TX Off Transient period of 10 μsec during UL CAL execution in receiving the UL CAL signal, it is assumed that the DL delayed wave of the adjacent operator base station does not exceed the self-reception saturation RMS level, and no splash diffusion of the frequency spectrum itself of the DL delayed wave of the distant operator base station in the adjacent frequency band due to hard clipping caused by self-reception complete saturation does not occur. Even in this case, the UL CAL signal is in a state where SINR degradation occurs due to the ACLR (adjacent leakage power distortion) of the DL delayed wave of the adjacent operator base station caused by the self-reception system nonlinear state due to the DL delayed wave level of the adjacent operator base station. Therefore, even if it is not completely saturated, it is necessary to be careful from the viewpoint of causing nonlinear distortion degradation to UL CAL reception. Incidentally, (c) of Fig. 8 is a time domain to frequency domain conversion of Symbol #9 before the UL CAL signal is performed in the TX Off Transient Period 10mμsec at the end of the same symbol, among the time signals of both Operator bands in (a) and (b) of Fig. 8, analyzed by FFT (Fast Fourier Transform), where the horizontal axis indicates frequency and the vertical axis indicates the power level of the own reception. However, in (c) of Fig. 8, the DL wave of the adjacent Operator base station is already always exceeding the own reception saturation RMS level. Therefore, although there is no UL CAL signal in Symbol #9, the own reception is already completely saturated by the DL wave of the distant Operator base station whose frequency band is adjacent, and it can be seen that the frequency spectrum of the DL wave of the distant Operator base station whose frequency band is adjacent covers the adjacent own reception band, causing spread interference over a wide frequency range.The following Symbol #10 is the first symbol of the GP2 symbol, which includes a 10μsec TX Off Transient period where a UL CAL signal is present and UL CAL is performed. (d) of Figure 8 is an FFT of Symbol #10 in (a) and (b) of Figure 8. (d) of Figure 8 shows that the 10μsec TX Off Transient period at the beginning of Symbol #10 continues to be above the full saturation level due to DL delay waves of the adjacent Operator base station. Therefore, in the case of (d) of Figure 8, the frequency splash interference level at the frequency band of the UL CAL frequency band of the self reception in the entire Symbol #10 is averaged and appears to be lower than the interference level of the Operator A band in (c) of Figure 8. However, within 10μsec of the TX Off Transient Period at the beginning of Symbol #10 where the UL CAL signal exists, as shown in (c) of Figure 8, the frequency spectrum of the UL CAL signal received by the transmitter is completely masked by the frequency splash interference level at full saturation due to DL delay waves of the adjacent Operator base station, and the SINR becomes negative. Therefore, in this interference situation, the UL CAL becomes completely insufficient, and the TRX stops due to the UL CAL Alarm being activated. Furthermore, in this situation, it is considered that the location and distance between the transmitter and the adjacent Operator base station will not change, so the longer the operation continues, the more the UL CAL Alarm will be generated, and the TRX will stop further, eventually heading towards the worst case situation where all TRXs stop.

[0053] During operation, the AAS900 grasps the amplitude and phase deviation of each RX312-n from the average amplitude phase of all RX312-n by transmitting and receiving the UL CAL signal, and judges an RX312-n with an abnormal amplitude and phase deviation as a UL CAL failure and issues a UL CAL Alarm. Therefore, if significant splash interference occurs that is greater than the reception level of the UL CAL signal and a UL CAL Alarm is continuously issued to a TRX31-n, the AAS900 judges that the TRX31-n is operating abnormally and stops it. If the TRX31-n are stopped one after another in this way, the AAS900 will not be able to withstand the operation, and eventually the AAS900 will stop operating.

[0054] Therefore, an object of the present disclosure is to solve the above-mentioned problems and provide a wireless communication device and a wireless communication method that can perform an uplink calibration operation regardless of the arrival of a delayed radiation signal from another wireless communication device. [Means for solving the problem]

[0055] According to one aspect, a wireless communication device includes: 1. A wireless communication device, comprising: A plurality of transmitters; A plurality of receivers; A calibration transceiver; a control unit that controls an uplink calibration operation that transmits an uplink calibration signal from the calibration transceiver to each of the plurality of receivers, The wireless communication device performs a TDD (Time Division Duplex) operation, The control unit controls each of the multiple transmitters to perform the uplink calibration operation in a predetermined time period prior to a downlink slot in which the each of the multiple transmitters transmits a downlink signal.

[0056] According to one aspect, a wireless communication method includes: 1. A wireless communication method performed by a wireless communication device, comprising: The wireless communication device includes: A plurality of transmitters; A plurality of receivers; A calibration transceiver; TDD (Time Division Duplex) operation. The wireless communication method includes a control step of controlling an uplink calibration operation of transmitting an uplink calibration signal from the calibration transceiver to each of the plurality of receivers; The control step includes controlling each of the plurality of transmitters to perform the uplink calibration operation in a predetermined time period prior to a downlink slot in which the transmitters transmit a downlink signal. Effect of the Invention

[0057] According to the above-described aspect, it is possible to provide a wireless communication device and a wireless communication method that are capable of performing an uplink calibration operation regardless of the arrival of a delayed radiation signal from another wireless communication device. [Brief description of the drawings]

[0058] [Figure 1] FIG. 1 is a circuit diagram showing an example of a circuit configuration of an AAS according to a related art. [Diagram 2] 1A and 1B are diagrams for explaining an example of DL CAL operation and DPD operation of an AAS according to the related art. [Diagram 3] 1A and 1B are diagrams illustrating examples of DL operation and DPD operation of an AAS according to a related art. [Figure 4] FIG. 1 is a diagram for explaining an example of UL CAL operation of an AAS according to the related art. [Diagram 5] FIG. 1 is a diagram illustrating an example of UL operation of an AAS according to a related art. [Figure 6] FIG. 13 is a diagram for explaining an example of timing at which an AAS according to the related art performs DL CAL operation and UL CAL operation. [Figure 7]1 is a diagram illustrating an example in which an AAS according to a related art is interfered with by a DL delayed radiation signal from an AAS of another operator. [Figure 8] FIG. 13 is a diagram illustrating an example in which an AAS according to the related art generates a frequency spectrum splash due to a DL delayed radiation signal from an AAS of another operator. [Figure 9] FIG. 2 is a circuit diagram showing an example of a circuit configuration of an AAS according to the first embodiment. [Figure 10] 1 is a diagram illustrating an example of timing at which an AAS according to the first embodiment performs DL CAL operation and UL CAL operation. FIG. [Figure 11] FIG. 11 is a diagram for explaining an example of timing at which an AAS according to the first embodiment performs a DL CAL operation and a UL CAL operation, in comparison with an example of timing at which an AAS according to the related art performs a DL CAL operation and a UL CAL operation. [Figure 12] FIG. 10 is a diagram for explaining an example of a control method for a receiving circuit in an FE unit when performing DL operation in the AAS described in Patent Document 1. [Figure 13] FIG. 10 is a diagram for explaining an example of a method for controlling a receiving circuit in an FE unit when a UL CAL operation is performed in the AAS described in Patent Document 1. [Figure 14] FIG. 10 is a diagram for explaining an example of a method for controlling a receiving circuit in an FE unit when performing a UL operation in the AAS described in Patent Document 1. [Figure 15] FIG. 11 is a circuit diagram showing an example of a circuit configuration in which an injection point for a UL CAL signal / DL CAL signal is shared between the antenna and the BPF in the AAS according to the first embodiment. [Figure 16] 11 is a circuit diagram showing an example of a circuit configuration of a wireless communication device according to a second embodiment. [Figure 17] FIG. 2 is a block diagram showing an example hardware configuration of a computer that realizes some of the functions of a wireless communication device according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the following description and drawings are omitted and simplified as appropriate for clarity of explanation. In addition, in each of the following drawings, the same elements are given the same reference numerals, and duplicated explanations are omitted as necessary. In addition, the specific numerical values ​​etc. shown below are merely examples for facilitating understanding of the present disclosure, and are not limited thereto.

[0060] <Embodiment 1> First, an example of a circuit configuration of the AAS100 according to the first embodiment will be described with reference to Fig. 9. It is assumed in Fig. 9 that the AAS100 is used as a base station. In Fig. 9, the AAS100 is described as having 32 antennas 41-1 to 41-32, which will be described later, but the number of antennas provided in the AAS100 is not limited to this and may be any number as long as it is plural.

[0061] As shown in FIG. 9, the AAS 100 according to the first embodiment has the same configuration as the AAS 900 according to the related art, but differs in the timing at which the UL CAL operation is performed. Specifically, the AAS 100 according to the first embodiment performs a UL CAL operation and a DL CAL operation, or performs only a UL CAL operation, in a time period immediately before a DL slot. In the latter case, the AAS 100 may perform a DL CAL operation in a time period after a DL slot (for example, a time period of a GP in a flexible slot of a DL slot) in the same manner as the AAS 900 according to the related art.

[0062] Next, the timing at which the AAS 100 according to the first embodiment performs DL CAL operation and UL CAL operation will be described with reference to Fig. 10. In Fig. 10, it is assumed that the AAS 100 performs UL CAL operation and DL CAL operation in a time period immediately before a DL slot. In Fig. 10, it is assumed that the AAS 100 performs TDD operation, etc., in the same manner as the AAS 900 in Fig. 6.

[0063] As shown in Fig. 10, the AAS 100 according to the first embodiment performs a UL CAL operation (i.e., an operation of transmitting a UL CAL signal from the CAL-TX 511 to each RX 312-n) during a time period immediately before a DL slot and during a time period of a Tx On Transient period (10 μsec) that is a time period for switching the TX 311-n from Off to On, and then performs a DL CAL operation (i.e., an operation of transmitting a DL CAL signal from each TX 311-n to the CAL-RX 512). Alternatively, the AAS 100 according to the first embodiment performs DL CAL (collective DL CAL or multiple DL CALs for each TX 311-n by frequency multiplexing the DL CAL signals of each TX 311-n) or only UL CAL sequentially using the entire Tx On Transient period (10 μsec) for each Frame. Alternatively, the AAS 100 according to the first embodiment may perform the UL CAL operation ahead of the Tx On Transient period and beyond the UL / DL Frame Timing (approximately 13 μsec or 20 μsec) (UL / DL Frame Timing-Tx On Transient period).

[0064] Next, the timing at which the AAS100 according to the first embodiment executes DL CAL operation and UL CAL operation will be described with reference to Fig. 11, in comparison with the timing at which the AAS900 according to the related art executes DL CAL operation and UL CAL operation. Fig. 11 shows the power level of the TX311-n at each of the DL and UL timings. The horizontal axis of Fig. 11 shows time, and the vertical axis shows the power level.

[0065] As shown in Fig. 11, the AAS900 according to the related art executes the UL CAL operation during the GP time period in the flexible slot after the DL slot and during the Tx Off Transient period. Alternatively, the AAS900 according to the related art executes the UL CAL operation beyond the Tx Off Transient period and into the GP.

[0066] In contrast, the AAS 100 according to the first embodiment performs the UL CAL operation in a time period immediately before the DL slot and during the Tx On Transient period. Alternatively, the AAS 100 according to the first embodiment performs the UL CAL operation ahead of the Tx On Transient period and into the UL / DL Frame Timing.

[0067] In addition, the AAS 900 according to the related art performs DL CAL operation during the GP time period in the flexible slot after the DL slot and during the Tx Off Transient period. In addition, the AAS 900 according to the related art performs DL CAL operation before performing UL CAL operation.

[0068] In contrast, the AAS 100 according to the first embodiment performs DL CAL operation in a time period immediately before the DL slot and during the time period of the Tx On Transient period. In addition, in the first example of DL CAL operation, the AAS 100 according to the first embodiment performs frequency multiplexing arrangement of all DL CAL signals output from each of the multiple TXs 311-n as DL CAL signals. As a result, even if the DL CAL signals output from each TX 311-n are combined in the CAL Network 60, the frequency arrangement of each Sub Carrier constituting the DL CAL signal made of OFDM is determined in advance so that they do not overlap in frequency. As a result, the first DL CAL signal arrangement and transmission method is a case in which DL CAL signals from all TXs 311-n are transmitted to the CAL-RX 512 in one DL CAL period. As another DL CAL signal arrangement and transmission method, transmission and reception of DL CAL signals is performed for each TX 311-n for each Frame. In other words, the second DL CAL signal allocation and transmission method is a method in which DL CAL signals that overlap in frequency from each TX311-n or DL ​​CAL signals that have a completely common frequency allocation are transmitted and received sequentially by time division multiplexing while switching the TX311-n that is the DL CAL target.

[0069] Alternatively, as another embodiment, DL CAL placement may be performed within a Tx Off Transient period of 10 μsec after the DL slot as in the conventional method (because the DL CAL signal level can be increased to the maximum rated output, even if a DL delayed wave occurs from a distant operator base station in an adjacent frequency band, there is no impact on the SINR of the DL CAL signal), and then only UL CAL may be performed within a Tx On Transient period of 10 μsec at the beginning of the DL slot.

[0070] In this way, the AAS 100 according to the first embodiment performs UL CAL operation in a time period immediately before the DL slot. As a result, even if the arrival time of a DL delayed radiation signal from an AAS of another Operator to the AAS 100 is delayed, the arrival time will be shifted to a time later than the time period in which the UL CAL operation (the operation of transmitting a UL CAL signal from the CAL-TX 511 to each RX 312-n) is performed. This prevents the UL CAL signal from being interfered with by a DL delayed radiation signal from an AAS of another Operator. Therefore, regardless of the arrival of a DL delayed radiation signal from an AAS of another Operator, UL CAL can be performed and UL CAL accuracy can be ensured.

[0071] Next, referring to Fig. 12 to Fig. 14, advantageous effects compared to the AAS described in Patent Document 1 (hereinafter referred to as AAS901) will be described. Fig. 12 to Fig. 14 show the circuit configuration of the receiving circuit in the FE unit of AAS901. Fig. 12 shows a method of controlling the receiving circuit when performing DL operation, Fig. 13 shows a method of controlling the receiving circuit when performing UL CAL operation, and Fig. 14 shows a method of controlling the receiving circuit when performing UL operation.

[0072] As shown in FIGS. 12 to 14, the reception circuit in the FE unit of the AAS 901 includes an LNA (Low Noise Amplifier) ​​301 which is a reception amplifier, a coupler 302, an SW 303, and a circulator 304.

[0073] As shown in FIG. 12, when AAS901 performs DL operation, SW303 between coupler 302 and antenna (ANT) is connected to the terminator side, and the AAS901 transmits a DL signal from the transmitter (TX) via the antenna (ANT).

[0074] Furthermore, as shown in FIG. 14, when AAS 901 performs UL operation, it receives a UL signal via an antenna (ANT) with SW 303 connected to the coupler 302 side.

[0075] Also, as shown in Fig. 13, when AAS901 performs UL CAL operation, SW303 is connected to the terminator side in the same manner as when performing DL operation. This has the effect of lowering the reception level of DL delayed radiation signals from the AAS of another operator by approximately -30 dB using the isolation of SW303. However, during UL CAL operation, the input end of LNA301 is open. Therefore, multiple reflections of the UL CAL signal from the calibration transceiver (CAL-TRX) occur, and ripples of the amplitude and phase of the UL CAL signal occur over a wide frequency band, which deteriorates the matching accuracy of matching the amplitude and phase characteristics between multiple receivers (RX) after UL CAL operation.

[0076] In contrast, the AAS100 according to the first embodiment can prevent the UL CAL signal from being interfered with by the DL delayed radiation signal from the AAS of another operator. Therefore, even if the AAS100 adopts the circuit configurations shown in Figs. 12 to 14 as the receiving circuit in the FE30, the UL CAL operation can be performed with the SW303 connected to the coupler 302 side. As a result, when the input end of the LNA301 is not open and the external real space is viewed from the antenna, it is expected that the return loss viewed from the antenna to the external environment will be as good as when it is terminated, unless there is a foreign object that may cause particularly significant shielding, blocking, or reflection near the antenna external environment. Therefore, the matching accuracy of the amplitude and phase characteristics between multiple receivers (RX) after the UL CAL operation is improved over a wide frequency band, and the UL CAL accuracy can be ensured.

[0077] Furthermore, in the AAS 100 according to the first embodiment, even when the input terminal of the receiving amplifier 33-n is directly connected to the antenna 41-n and UL CAL operation is performed, it is possible to prevent the UL CAL signal from being interfered with by a DL delayed radiation signal from an AAS of another operator. Therefore, the injection point of the UL CAL signal / DL CAL signal can be shared between the antenna 41-n and the BPF 36-n.

[0078] With reference to Fig. 15, a circuit configuration example will be described in which an injection point for a UL CAL signal / DL CAL signal is shared between the antenna 41-n and the BPF 36-n in the AAS 100 according to the first embodiment. In Fig. 15, the optical transceiver 10 and the BB unit 20 shown in Fig. 9 are omitted.

[0079] As shown in FIG. 15, the AAS 100 according to the first embodiment includes 32 transceiver-frontend (TRX-Frontend) units 30-n, a main board 50, calibration networks (CAL Networks) 60-1 and 60-2, and antenna arrays 40-1 and 40-2.

[0080] The TRX-Frontend unit 30-n is a unit that integrates the TX 311-n, the TX 311-n, the SW 35-n, the BPF 36-n, the transmission amplifier 32-n, the reception amplifier 33-n, and the coupler 34-n into one unit. However, the transmission amplifier 32-n, the reception amplifier 33-n, and the coupler 34-n are omitted from the illustration in Fig. 15. The combination of the 32 TRX-Frontend units 30-n corresponds to the FE unit 30 shown in Fig. 9. The main board 50 integrates the CAL-TRX 51, the SW 52, and the hybrid (HYB) 53 into a single unit.

[0081] The CAL Network 60-1 is a combination of 16 couplers (CPL) 61-1 to 61-16 and a hybrid network (HYB Network) 62-1, which are integrated into one unit. The CAL Network 60-2 is a combination of 16 couplers 61-17 to 61-32 and a HYB Network 62-2, which are integrated into one unit. The combination of the CAL Networks 60-1 and 60-2 corresponds to the CAL Network 60 shown in FIG.

[0082] The antenna array 40-1 is configured by combining 16 antennas 41-1 to 41-16 into one unit, while the antenna array 40-2 is configured by combining 16 antennas 41-17 to 41-32 into one unit.

[0083] The 16 TRX-Frontend units 30-1 to 30-16 are connected to a CAL network 60-1 via a connector 70. The 16 TRX-Frontend units 30-17 to 30-32 are connected to a CAL network 60-2 via a connector 70. The main board 50 is connected to each of the CAL networks 60-1 and 60-2 via the connector 70.

[0084] In this way, the AAS100 according to the first embodiment can simplify the circuit configuration because the circuit elements can be unitized. Also, the AAS100 according to the first embodiment can simplify the connection between the units because the units can be connected via the connector 70.

[0085] As described above, the AAS 100 according to the first embodiment performs UL CAL operation in a time period immediately before the DL slot. As a result, even if the arrival time of the DL delayed radiation signal from the AAS of another Operator to the AAS 100 is delayed, the arrival time will be shifted to a time later than the time period in which the UL CAL operation (the operation of transmitting the UL CAL signal from the CAL-TX 511 to each RX 312-n) is performed. Therefore, it is possible to prevent the UL CAL signal from being interfered with by the DL delayed radiation signal from the AAS of another Operator. Therefore, regardless of the arrival of the DL delayed radiation signal from the AAS of another Operator, the UL CAL can be performed and the UL CAL accuracy can be ensured.

[0086] <Embodiment 2> The second embodiment corresponds to an embodiment that conceptually illustrates the first embodiment described above. First, an example of a circuit configuration of a wireless communication device 100A according to the second embodiment will be described with reference to Fig. 16. Note that Fig. 16 assumes that the wireless communication device 100A is used as a base station.

[0087] As shown in FIG. 16, the wireless communication device 100A according to the second embodiment includes a control unit 22, m (m is an integer equal to or greater than 2) transmitters (TX) 311-1 to 311-m, m receivers (RX) 312-1 to 312-m, and a calibration transceiver (CAL-TRX) 51.

[0088] In the following description, when there is no need to specify which of the TXs 311-1 to 311-m it is, it will be referred to as TX 311-n (n=1, . . . , m). Similarly, the RXs 312-1 to 312-m will be referred to as RX 312-n.

[0089] The control unit 22 corresponds to the BB unit 20 in the above-mentioned first embodiment. The m TXs 311-n and the m RXs 312-n are provided corresponding to the m antennas (not shown), respectively.

[0090] The control unit 22 controls an uplink calibration (UL CAL) operation, which is an operation of transmitting an uplink calibration (UL CAL) signal from the CAL-TRX 51 to each of the m RXs 312-n.

[0091] Here, the wireless communication device 100A performs a TDD (Time Division Duplex) operation. Furthermore, the control unit 22 controls each of the m TXs 311-n to perform a UL CAL operation in a predetermined time period before a downlink slot (DL slot) in which the TXs 311-n transmit a downlink (DL) signal.

[0092] As a result, even if the arrival time of a DL delayed radiation signal from a wireless communication device of another Operator at the wireless communication device 100A is delayed, the arrival time will be shifted to a time later than the time period in which the UL CAL operation (the operation of transmitting a UL CAL signal from the CAL-TRX 51 to each RX 312-n) is performed. Therefore, the UL CAL signal is prevented from being interfered with by a DL delayed radiation signal from a wireless communication device of another Operator. Therefore, regardless of the arrival of a DL delayed radiation signal from a wireless communication device of another Operator, UL CAL can be performed and UL CAL accuracy can be ensured.

[0093] The control unit 22 may control a downlink calibration (DL CAL) operation that transmits a downlink calibration (DL CAL) signal from each of the m TXs 311-n to the CAL-TRX 51.

[0094] Furthermore, the control unit 22 may perform control so that a DL CAL operation is performed in a predetermined time period before a DL slot. In this case, the control unit 22 may perform control so that a UL CAL operation is performed in a predetermined time period before a DL slot, and then a DL CAL operation is performed.

[0095] Alternatively, the control unit 22 may perform control so that the DL CAL operation or the UL CAL operation is sequentially performed for each Frame during a predetermined time period before the DL slot. Alternatively, the control unit 22 may perform control so that only the UL CAL operation is performed for each frame in a predetermined time period before the DL slot, and the DL CAL operation is performed in a second predetermined time period after the DL slot.

[0096] Also, the predetermined time period before the DL slot may be set within the time width of a period for switching each of the m TXs 311-n from Off to On (for example, a Tx On Transient period). Alternatively, the predetermined time period before the DL slot may be set within the time width of an uplink / downlink frame timing (UL / DL Frame Timing).

[0097] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present invention.

[0098] For example, some of the functions of the wireless communication device (including the AAS) according to the present disclosure can be realized by causing a processor such as a CPU (Central Processing Unit) to execute a program. An example of the hardware configuration of a computer 100B that realizes some of the functions of the wireless communication device according to the present disclosure will be described with reference to FIG. As shown in FIG. 17, the computer 100B includes a processor 81 and a memory 82.

[0099] The processor 81 may be, for example, a microprocessor, a CPU, or an MPU (Micro Processing Unit), or the processor 81 may include multiple processors.

[0100] The memory 82 is configured by a combination of volatile memory and non-volatile memory. The memory 82 may include storage located away from the processor 81. In this case, the processor 81 may access the memory 82 via an I (Input) / O (Output) interface (not shown).

[0101] A program is stored in the memory 82. When the program is loaded into the computer 100B, the program includes a set of instructions (or software code) for causing the computer 100B to perform some of the functions of the AAS 100 or the wireless communication device 100A according to the above-mentioned first or second embodiment. The components of the AAS 100 or the wireless communication device 100A described above may be realized by the processor 81 reading and executing the program stored in the memory 82. Furthermore, the components having a storage function in the AAS 100 or the wireless communication device 100A described above may be realized by the memory 82.

[0102] The above-mentioned programs may also be stored on non-transitory computer-readable media or tangible storage media. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic or other form of propagated signal. [Explanation of symbols]

[0103] 10 Optical Transceiver 20 Baseband (BB) section 21-1~21-32 DPD Section 22 Control section 30 Front end (FE) section 30-1~30-32 Transmitter-Receiver-Frontend (TRX-Frontend) Section 31-1~31-32 Transmitter / Receiver (TRX) 311-1~311-m Transmitter (TX) 312-1~312-m Receiver (RX) 32-1~32-32 Transmitting amplifier 33-1~33-32 Receiving amplifier 34-1~34-32 Coupler 35-1~35-32 Switch (SW: Switch) 36-1~36-32 Band-pass filter (BPF: Band-pass filter) 40-1, 40-2 Antenna Array 41-1~41-32 Antenna 50 Main Board 51 Calibration transmitter / receiver (CAL-TRX) 52 Switch 53 Hybrid (HYB) 60 Calibration Network (CAL Network) 60-1,60-2 Calibration Network (CAL Network) 61-1~61-32 Coupler (CPL) 62-1, 62-2 Hybrid Network (HYB Network) 70 Connector 81 Processor 82 Memory 100 AAS 100A Wireless communication equipment 100B Computer

Claims

1. 1. A wireless communication device, comprising: A plurality of transmitters; A plurality of receivers; A calibration transceiver; a control unit that controls an uplink calibration operation that transmits an uplink calibration signal from the calibration transceiver to each of the plurality of receivers, The wireless communication device performs a time division duplex (TDD) operation, The control unit controls the uplink calibration operation to be performed in a predetermined time period before a downlink slot in which each of the plurality of transmitters transmits a downlink signal. Wireless communication device.

2. the control unit controls a downlink calibration operation of transmitting a downlink calibration signal from each of the plurality of transmitters to the calibration transceiver; The control unit controls to perform the downlink calibration operation in the predetermined time period before the downlink slot. The wireless communication device of claim 1 .

3. The control unit controls to perform the uplink calibration operation in the predetermined time period before the downlink slot, and to perform the downlink calibration operation thereafter. The wireless communication device according to claim 2 .

4. the control unit controls the downlink calibration operation or the uplink calibration operation to be sequentially performed for each frame in the predetermined time period before the downlink slot; The wireless communication device according to claim 2 .

5. the control unit controls so that only the uplink calibration operation is performed for each frame in the predetermined time period before the downlink slot, and the downlink calibration operation is performed in a second predetermined time period after the downlink slot. The wireless communication device according to claim 2 .

6. the predetermined time period before the downlink slot is set within a time width of a period for switching each of the plurality of transmitters from Off to On; A wireless communication device according to any one of claims 1 to 5.

7. The predetermined time period before the downlink slot is set within a time width of an uplink / downlink frame timing. A wireless communication device according to any one of claims 1 to 5.

8. 1. A wireless communication method performed by a wireless communication device, comprising: The wireless communication device includes: A plurality of transmitters; A plurality of receivers; A calibration transceiver; TDD (Time Division Duplex) operation is performed. The wireless communication method includes a control step of controlling an uplink calibration operation of transmitting an uplink calibration signal from the calibration transceiver to each of the plurality of receivers; In the control step, the uplink calibration operation is controlled to be performed in a predetermined time period before a downlink slot in which each of the plurality of transmitters transmits a downlink signal. A wireless communication method.

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