Wireless communication device, wireless communication method, and wireless communication system

Abstract

To maintain spatial multiplexing performance of a wireless communication device even when a failure occurs in a transceiver in the wireless communication device.SOLUTION: A wireless communication device includes a plurality of transceivers, a calibration transceiver, and a control unit. The control unit includes a failure detection unit that detects a failure of each of the plurality of transceivers on the basis of a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation, and a reconstruction unit that executes a self-healing process to reconstruct a downlink beamforming weight for spatial multiplexing using a transceiver other than a failed transceiver among the plurality of transceivers.SELECTED DRAWING: Figure 55

Description

[Technical field]

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

[0002] Active antenna systems (AAS) for 5G (5th Generation) employ a full digital beamforming method that can achieve high frequency utilization efficiency (for example, Patent Document 1). In addition, AAS is expected to realize high-speed and large-capacity data transmission and improved frequency utilization efficiency through spatial multiplexing performance using Massive MIMO (Multi Input Multi Output). 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 on a surface-by-surface basis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-503116 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, it is expected that AAS will be deployed on a large scale in the future, and the total number of transceivers (TRX) operating within the AAS will increase accordingly. However, as the total number of TRXs within an AAS increases, there is a concern that the number of TRX failures will increase due to aging and other factors.

[0005] The inventor found that as the number of TRX failures in the AAS increases, the variation in the null depth in the direction of terminals other than the desired terminal becomes significantly larger, and the spatial multiplexing performance is significantly deteriorated. In the following, we will explain the effect of an increase in the number of TRX failures in the AAS on the null depth, which is important in spatial multiplexing.

[0006] First, the configuration of the AAS 900 according to the related art will be described. Fig. 1 shows an example of the circuit configuration of the AAS 900 according to the related art. Fig. 2 shows an example of the specifications of the AAS 900 according to the related art. 1 and 2, the AAS900 is equipped with a total of 64 antenna elements, each consisting of a ±45° polarized patch antenna with a horizontal 8 x vertical 4 x 2 polarization configuration. The AAS900 is also equipped with 32 TRXs, each consisting of 8 horizontal x 2 vertical x 2 polarization configuration, with two vertical antenna elements connected to one TRX.

[0007] 1 and 2, it is assumed that the AAS 900 is used as a base station. Therefore, the AAS900 performs DL operation to transmit DL (Downlink) signals to a plurality of UEs (User Equipments) (not shown) in which a Beam Forming Weight is multiplied on a DATA transmission stream (time signal) for each layer (in an embodiment described later, as an example, two-layer transmission is performed in cross-polarized MIMO) to each UE. Also, the AAS900 performs UL operation by receiving UL (Uplink) signals from a plurality of UEs with all antenna elements of the AAS900.

[0008] 1 and 2, an AAS 900 according to the related art includes optical transceivers 10A and 10B, a baseband (BB) unit 20, 32 TRXs 31-0 to 31-31, 32 switches (SWs) 32-0 to 32-31, an antenna 40, a calibration transceiver (CAL-TRX) 51, a SW 52, and a calibration network (CAL Network) 60. In the following, when it is not necessary to specify which TRX 31-0 to 31-31 it is, it will be referred to as TRX 31-n (n = 0,...,31). Similarly, SWs 32-0 to 32-31 will be referred to as SWs 32-n.

[0009] The optical transceivers 10A and 10B perform photoelectric conversion of signals transmitted and received between a distribution unit (DU: Distributed Unit) (not shown) and the BB section 20, and vice versa. When performing DL operation, the BB unit 20 outputs the DL signals output from the optical transceivers 10A and 10B to each TRX31-n. When performing UL operation, the BB unit 20 outputs the UL signals output from each TRX31-n to the optical transceivers 10A and 10B.

[0010] When performing DL operation, the TRX31-n converts DL signals output from the BB unit 20, which are multiplied by a beam forming weight for each layer signal to a plurality of UEs, from an IQ (In-phase and Quadrature) signal to an RF (Radio Frequency) signal, amplifies the DL signals, and outputs the converted signals to the SW32-n. When performing UL operation, the TRX31-n amplifies UL signals output from the SW32-n, converts the UL signals to an IQ signal, and outputs the converted signals to the BB unit 20. For this reason, the TRX31-n includes a transmitter (TX) that converts DL signals, which are multiplied by a beam forming weight for each UE in the BB unit 20, from an IQ signal to an RF signal, and a transmission amplifier that amplifies the DL signals output from the TX. The TRX31-n also includes a receiving amplifier that amplifies UL signals through a plurality of antennas configured as an array of multiple elements, a receiver (RX) that converts UL signals output from the receiving amplifier from an RF signal to an IQ signal, and the like. The SW32-n may be provided in the TRX31-n.

[0011] SW32-n is a switch that switches the connection between TRX31-n and the antenna 40 and the CAL Network 60. When performing DL operation, SW32-n outputs the DL signal output from TRX31-n to the antenna 40. When performing UL operation, SW32-n outputs the UL signal received by the antenna 40 to TRX31-n.

[0012] The antenna 40 includes a total of 64 antenna elements as described above. When performing DL operation, each antenna element transmits a DL signal output from SW32-n to the UE. When performing UL operation, each antenna element receives a UL signal from the UE and outputs it to SW32-n. Details of each antenna element constituting the antenna 40 will be described later.

[0013] In addition, in order to perform UL Channel Sounding and DL BF with high accuracy, AAS900 performs DL CAL (Calibration) operation to match the amplitude, phase, and frequency characteristics between multiple TXs within AAS900, and UL CAL operation to match the amplitude, phase, and frequency characteristics between multiple RXs within AAS900.

[0014] When performing a DL CAL operation, the BB unit 20 outputs a DL CAL signal to each TRX 31-n, and when performing a UL CAL operation, the BB unit 20 outputs a UL CAL signal to the CAL-TRX 51.

[0015] When performing DL CAL operation, TRX31-n converts the DL CAL signal output from BB unit 20 from an IQ signal to an RF signal, amplifies the signal, and outputs the signal to SW32-n. When performing UL CAL operation, TRX31-n amplifies the UL CAL signal output from SW32-n, converts the signal from an RF signal to an IQ signal, and outputs the signal to BB unit 20.

[0016] When performing DL CAL operation, SW32-n outputs the DL CAL signal output from TRX31-n to the CAL Network 60. When performing UL CAL operation, SW32-n outputs the UL CAL signal output from the CAL Network 60 to TRX31-n.

[0017] When performing DL CAL operation, the CAL Network 60 combines the DL CAL signals output from each SW32-n and outputs the combined signal to SW52. When performing UL CAL operation, the CAL Network 60 distributes the UL CAL signal output from SW52 and outputs the distributed signal to each SW32-n.

[0018] 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.

[0019] When performing DL CAL operation, CAL-TRX 51 converts the DL CAL signal output from SW52 from an RF signal to an IQ signal and sends it to BB unit 20. When performing UL CAL operation, CAL-TRX 51 converts the UL CAL signal output from BB unit 20 from an IQ signal to an RF signal and outputs it to SW52. For this reason, CAL-TRX 51 is equipped with a calibration receiver (CAL-RX) that converts the DL CAL signal output from SW52 from an RF signal to an IQ signal, a calibration transmitter (CAL-TX) that converts the UL CAL signal output from BB unit 20 from an IQ signal to an RF signal, and the like.

[0020] When performing DL CAL operation, the BB unit 20 receives the DL CAL signal output from the CAL-RX in the CAL-TRX 51. This DL CAL signal is in a state in which the DL CAL signals output from the TX in each TRX 31-n are frequency-multiplexed and then combined. Therefore, the BB unit 20 separates and extracts the DL CAL signal output from the CAL-RX in the CAL-TRX 51 for each TX in each TRX 31-n, and calculates the DL CAL Weight of the TX in each TRX 31-n based on the extracted DL CAL signal. The DL CAL Weight calculated for the TX in each TRX 31-n is multiplied by the DL signal passing through that TX during DL operation.

[0021] Furthermore, when performing UL CAL operation, the BB unit 20 calculates the UL CAL Weight of the RX in each TRX 31-n based on the UL CAL signal output from the RX in each TRX 31-n. The UL CAL Weight calculated for the RX in each TRX 31-n is multiplied by the UL signal that has passed through that RX during UL operation.

[0022] Next, a configuration of a wireless communication system including an AAS 900 according to the related art as a base station will be described. Fig. 3 shows an example of the configuration of the wireless communication system. Fig. 4 shows an example of the components constituting the wireless communication system and the specifications of a UE.

[0023] 3 and 4, the wireless communication system includes a centralized base station (CU: Center Unit) 300 and an access point (AP: Access Point) 400. The wireless communication system shown in FIG. 3 is a base station system having a centralized-RAN (C-RAN) configuration in which the CU 300 controls the AP 400.

[0024] 3 shows three APs 400. Each AP 400 includes one DU 200 and one or more AASs 900. The DU 200 processes digital signals of the BF and PHY (Physical layer). The DU 200 and the AAS 900 are connected by a multi-core multimode optical fiber (optical fronthaul).

[0025] The CU 300 and each AP 400 are connected via a front haul 500. The front haul 500 is, for example, an optical wired network or a millimeter wave wireless network.

[0026] Each AP 400 allocates two layers per UE through Zero-Forcing (ZF) processing, enabling spatial multiplexing of up to eight UEs (a total of 16 layers). The CU 300 performs hybrid automatic repeat-request (H-ARQ) and adaptive modulation and coding (AMC). The AMC is controlled by outer loop link adaptation (OLLA) so as to transmit with a modulation and coding scheme (MCS) that satisfies a block error rate (BLER) of 10%.

[0027] Next, the configuration of the antenna 40 in the AAS 900 according to the related art will be described. Fig. 5 shows a perspective view illustrating an example of the configuration of the antenna 40. Fig. 6 shows a front view illustrating an example of the configuration of a ±45° polarized antenna that constitutes the antenna 40.

[0028] As shown in Fig. 5 and Fig. 6, the antenna 40 is configured by integrating a -45° polarized antenna and a +45° polarized antenna. Each of the ±45° polarized antennas includes a total of 32 antenna elements, 8 horizontal and 4 vertical. In each of the ±45° polarized antennas, two vertical antenna elements are grouped, and the two grouped antenna elements are connected to one TRX31-n. For example, the two antenna elements at the left end and bottom end of the -45° polarized antenna are connected to TRX31-0. In this way, 16 TRX31-0 to 31-15 are respectively connected to the -45° polarized antenna, and 16 TRX31-16 to 31-31 are respectively connected to the +45° polarized antenna.

[0029] Here, based on the DL beamforming pattern to the UE located in front of the AAS900, in order to grasp the extent of the influence on the radiation pattern of the DL signal due to the increase in the number of TRX31-n failures, we focused on the 1st null depth, which is important in spatial multiplexing, and performed a simulation to grasp the characteristics of the degradation and variation. Note that the 1st null refers to the null closest to the main lobe of the radiation pattern, and the 1st null depth refers to the null depth of the 1st null.

[0030] Here, in the AAS900, when all 32 TRX31-n are normal, the DL / UL Beam forming Weight (BFW) of the DL and UL signals passing through each TRX31-n is left unchanged from the Boresight radiation setting (1+j0), and the BFW of the faulty TRX31-n is set to zero to stop transmission and reception at the faulty TRX31-n.

[0031] Under this premise, while increasing the number of TRX31-n failures, 1,000 different TRX31-n failure locations were randomly selected for each number of failures, and the angular spectrum of the horizontal angle was calculated for each of the 1,000 different failure locations.

[0032] For example, if the number of faulty TRX31-n is three, three types of antenna groups consisting of two grouped antenna elements are randomly selected in 1000 ways (Figure 7 shows an example of the three types of antenna groups selected). Then, the three TRX31-n connected to each of the selected three types of antenna groups are considered to be faulty, and transmission and reception are stopped. Then, the remaining 29 TRX31-n and 58 antenna elements continue spatial multiplexing and Massive-MIMO operation, and the angular spectrum of the horizontal angle at this time is calculated.

[0033] In this manner, 1000 fault locations of TRX31-n were randomly selected for each number of faults of TRX31-n, and the angle spectrum of the horizontal angle was calculated for each of the 1000 fault locations, and the calculated angle spectrum was overlaid. As a representative example, Figs. 8 to 11 show the overlaid angle spectrum of the horizontal angle of ±45° polarization when the number of faults of TRX31-n is 1 / 2 / 4 / 8, respectively. In Figs. 8 to 11, the horizontal axis indicates the horizontal angle as seen from the AAS900, and the vertical axis indicates EIRP (Equivalent Isotropic Radiated Power). As shown in Figs. 8 to 11, it can be seen that the disturbance and variation of the sidelobe and null significantly expands and deteriorates as the number of faults of TRX31-n increases.

[0034] Furthermore, in order to more clearly grasp the degradation of the null depth due to an increase in the number of TRX31-n failures, an envelope pattern was extracted from the overlapping of the angle spectrum of each horizontal angle in Figs. 8 to 11. Then, in Figs. 12 to 15, the extracted envelope pattern and the angle spectrum (dashed line) when all 32 TRX31-n are normal are overlapping. That is, in Figs. 12 to 15, the envelope patterns of the angle spectrum when the number of TRX31-n failures is 1 / 2 / 4 / 8, respectively, are overlapping with the angle spectrum (dashed line) when all 32 TRX31-n are normal. As shown in Figs. 12 to 15, it can be seen that as the number of TRX31-n failures increases, the worst value of the null depth (1st null depth) between the main lobe and the side lobe and the worst value of the null depth between each side lobe become shallower and deteriorate.

[0035] In addition, when focusing on the 1st Null depth when the number of faults in TRX31-n is 1 / 2 / 4 / 8, a histogram is shown in FIG. 16, in which the horizontal axis represents the 1st Null depth at each of 1,000 fault locations for each number of faults in TRX31-n, and the vertical axis represents the occurrence frequency of each 1st Null depth.

[0036] We also focused on the 1st Null depth when the number of faults in TRX31-n was further increased. That is, in Fig. 17 to Fig. 20, we calculated the 1st Null depth at each of 1000 fault locations when the number of faults in TRX31-n was 3 / 6 / 12 / 24, respectively, and showed the calculation results as a cumulative distribution function (CDF).

[0037] As shown in FIG. 16 to FIG. 20, it can be seen that as the number of failures in TRX31-n increases, the variation in the 1st Null depth also gradually increases.

[0038] As described above, it was clearly confirmed that as the number of TRX31-n failures increases, the variation in the 1st Null depth also increases significantly, resulting in a variation of 10 dB to 20 dB or more. Therefore, even if only a few of the 32 TRX31-n fail, if the failures are left unchecked, the DL SINR (Signal-to-Interference-plus-Noise Ratio) will be significantly degraded during spatial multiplexing, and as a result, the spatial multiplexing performance will be significantly degraded.

[0039] The AAS900 has the redundancy of being equipped with multiple TRX31-n, so going forward, it will be important to take advantage of this redundancy and use only the normal TRX31-n to maintain the spatial multiplexing performance of the AAS900.

[0040] In view of the above-mentioned problems, an object of the present disclosure is to provide a wireless communication device, a wireless communication method, and a wireless communication system that are capable of maintaining the spatial multiplexing performance of the wireless communication device even when a failure occurs in a transceiver within the wireless communication device. [Means for solving the problem]

[0041] According to one aspect, a wireless communication device includes: A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; and a reconstruction unit that executes a self-healing process to reconstruct a downlink beamforming weight for spatial multiplexing using one of the plurality of transceivers other than the failed transceiver.

[0042] According to one aspect, a wireless communication method includes: A wireless communication method for a wireless communication device including a plurality of transceivers, a calibration transceiver, and a control unit, comprising: a failure detection step of detecting a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; and a reconfiguration step of executing a self-healing process for reconfiguring a downlink beamforming weight for spatial multiplexing using one of the plurality of transceivers other than the failed transceiver.

[0043] According to one aspect, a wireless communication system includes: a first wireless communication device; a second wireless communication device, The first wireless communication device, A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation, The second wireless communication device, a reconfiguration unit that executes a self-healing process to reconfigure a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers; Wireless communication system. Effect of the Invention

[0044] According to the above-mentioned aspects, it is possible to provide a wireless communication device, a wireless communication method, and a wireless communication system that are capable of maintaining the spatial multiplexing performance of the wireless communication device even when a failure occurs in the transceiver within the wireless communication device. [Brief description of the drawings]

[0045] [Figure 1] FIG. 2 is a circuit diagram showing an example of a circuit configuration of an AAS. [Diagram 2] FIG. 1 is a diagram showing an example of the specifications of an AAS. [Diagram 3] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 4] FIG. 2 is a diagram showing an example of components constituting a wireless communication system and specifications of a UE. [Diagram 5] FIG. 2 is a perspective view showing an example of the configuration of an antenna in an AAS. [Figure 6] FIG. 2 is a front view showing an example of the configuration of a ±45° polarized antenna that constitutes the antenna in the AAS. [Figure 7] FIG. 13 is a diagram showing an example of the locations of faulty TRXs when the number of faulty TRXs is three. [Figure 8] FIG. 13 is a diagram showing an example in which the angular spectrum of the horizontal angle of ±45° polarization at each of 1000 different fault locations is overlaid when there is one faulty TRX. [Figure 9] FIG. 13 is a diagram showing an example in which the angular spectrum of the horizontal angle of ±45° polarization at each of 1000 different fault locations is overlaid when the number of faulty TRXs is two. [Figure 10]FIG. 13 is a diagram showing an example in which the angular spectrum of the horizontal angle of ±45° polarization at each of 1000 different fault locations is overlaid when the number of faulty TRXs is four. [Figure 11] FIG. 13 is a diagram showing an example in which the angular spectrum of the horizontal angle of ±45° polarization at each of 1000 different fault locations is overlaid when the number of faulty TRXs is eight. [Figure 12] FIG. 9 is a diagram showing an example in which the envelope pattern extracted from FIG. 8 is overlaid on the angle spectrum when all 32 TRXs are normal, in the case where there is one faulty TRX. [Figure 13] FIG. 10 is a diagram showing an example in which the envelope pattern extracted from FIG. 9 is overlaid on the angle spectrum when all 32 TRXs are normal, in a case where the number of faulty TRXs is two. [Figure 14] FIG. 11 is a diagram showing an example in which the envelope pattern extracted from FIG. 10 is overlaid on the angle spectrum when all 32 TRXs are normal, in a case where the number of faulty TRXs is four. [Figure 15] FIG. 12 is a diagram showing an example in which the envelope pattern extracted from FIG. 11 is overlaid on the angle spectrum when all 32 TRXs are normal, in a case where the number of faulty TRXs is eight. [Figure 16] FIG. 13 is a diagram showing an example of a histogram in which the horizontal axis indicates the 1st Null depth at each of 1000 fault locations for each number of faults in the TRX, and the vertical axis indicates the frequency of occurrence of each 1st Null depth. [Figure 17] FIG. 13 is a diagram showing an example in which the 1st Null depth is calculated for each of 1000 fault locations when the number of faults in a TRX is three, and the calculation results are expressed as a cumulative distribution function. [Figure 18] FIG. 13 is a diagram showing an example in which the 1st Null depth is calculated for each of 1000 fault locations when the number of faults in a TRX is six, and the calculation results are expressed as a cumulative distribution function. [Figure 19] FIG. 13 is a diagram showing an example in which the 1st Null depth is calculated for each of 1000 fault locations when the number of faults in a TRX is 12, and the calculation results are expressed as a cumulative distribution function. [Figure 20]FIG. 13 is a diagram showing an example in which the 1st Null depth is calculated for each of 1000 fault locations when the number of faults in a TRX is 24, and the calculation results are expressed as a cumulative distribution function. [Figure 21] FIG. 2 is a circuit diagram showing an example of a circuit configuration of an AAS. [Figure 22] FIG. 1 is a diagram illustrating an example of an outdoor actual environment assumed in a simulation. [Diagram 23] FIG. 13 is a conceptual diagram showing an example of a pseudo Self-Healing process. [Figure 24] FIG. 13 is a conceptual diagram showing an example of a pseudo Self-Healing process. [Diagram 25] FIG. 13 is a conceptual diagram showing an example of a pseudo Self-Healing process. [Figure 26] FIG. 11 is a flow diagram showing an example of the flow of a pseudo self-healing process. [Figure 27] FIG. 13 is a schematic diagram showing an example of a pseudo Self-Healing process. [Figure 28] A figure showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#0 when all 32 TRXs are normal. [Figure 29] A figure showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#1 when all 32 TRXs are normal. [Diagram 30] A figure showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#2 when all 32 TRXs are normal. [Diagram 31] FIG. 11 is a diagram showing an example of the two-layer average DL SINR and total transmission capacity of DL signals to each of three UEs, UE #0, UE #1, and UE #2, when all 32 TRXs are normal. [Diagram 32] FIG. 13 is a diagram showing an example of the two-layer average DL SINR and total transmission capacity of DL signals to each of three UEs, UE#0, UE#1, and UE#2, before and after self-healing is performed when there are three faulty TRXs. [Diagram 33]FIG. 13 is a diagram showing an example of the two-layer average DL SINR and total transmission capacity of DL signals to each of three UEs, UE#0, UE#1, and UE#2, before and after self-healing is performed when there are six faulty TRXs. [Diagram 34] FIG. 11 is a diagram showing an example of the two-layer average DL SINR and total transmission capacity of DL signals to each of three UEs, UE#0, UE#1, and UE#2, before and after self-healing is performed when there are 12 faulty TRXs. [Diagram 35] FIG. 13 is a diagram showing an example of fault locations where the 1st Null depth is the worst value when the number of faults in a TRX is three. [Diagram 36] This figure shows an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 when spatial multiplexing of three UEs, UE#0, UE#1, and UE#2, is performed after self-healing is performed with the TRX failure location in the state shown in Figure 35. [Figure 37] A figure showing an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 after self-healing is performed when the TRX failure location is in the state shown in Figure 35. [Figure 38] FIG. 13 is a diagram showing an example of fault locations where the 1st Null depth is the worst value when the number of faults in a TRX is six. [Figure 39] This figure shows an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 when spatial multiplexing of three UEs, UE#0, UE#1, and UE#2, is performed after self-healing is performed with the TRX failure location in the state shown in Figure 38. [Diagram 40] A figure showing an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 after self-healing is performed when the TRX failure location is in the state shown in Figure 38. [Diagram 41] FIG. 13 is a diagram showing an example of fault locations where the 1st Null depth is the worst value when the number of faults in a TRX is 12. [Diagram 42] This figure shows an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 when spatial multiplexing of three UEs, UE#0, UE#1, and UE#2, is performed after self-healing is performed with the TRX failure location in the state shown in Figure 41. [Diagram 43] A figure showing an example of the radiation pattern of a DL signal radiated from an AAS to UE#0 after self-healing is performed when the TRX failure location is in the state shown in Figure 41. [Diagram 44] A figure showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#0 when all 32 TRXs are normal. [Diagram 45] 13 is a diagram showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#0 before performing self-healing when the number of faulty TRXs is 12. FIG. [Diagram 46] 13 is a diagram showing an example of a radiation pattern of a DL signal radiated from an AAS to UE#0 after performing self-healing when the number of faulty TRXs is 12. FIG. [Figure 47] This figure shows an example in which the average DL SINR of three UEs, UE#0, UE#1, and UE#2, before and after Self-Healing is performed when the number of faulty TRXs is 3 / 6 / 12 / 18 / 24, respectively, is compared with the average DL SINR when all 32 TRXs are normal. [Figure 48] This figure shows an example in which the average transmission capacity of three UEs, UE#0, UE#1, and UE#2, before and after Self-Healing is performed, when the number of faulty TRXs is 3 / 6 / 12 / 18 / 24, respectively, is compared with the average transmission capacity when all 32 TRXs are normal. [Figure 49] FIG. 11 is a diagram showing an example of average power loss for three UEs UE#0, UE#1, and UE#2 before and after execution of self-healing when the number of faulty TRXs is 3 / 6 / 12 / 18 / 24, respectively. [Figure 50] FIG. 2 is a diagram showing an example of the arrangement of antenna elements that configure an antenna. [Figure 51] This figure shows an example in which the radiation pattern of the DL signal radiated from the AAS to the UE before Self-Healing is performed is compared for each failure location when there is one faulty TRX, with the radiation pattern of the DL signal radiated from the AAS to the UE when all 32 TRXs are normal. [Figure 52]FIG. 13 is a diagram showing an example in which the horizontal axis represents the column number of the fault location and the vertical axis represents the 1st Null depth before Self-Healing is performed for each column number when there is one fault in the TRX. [Diagram 53] FIG. 13 is a diagram showing an example of the 1st Null depth before execution of Self-Healing for each fault location of sample numbers 1 to 4 when the number of faults in the TRX is two. [Figure 54] FIG. 13 is a diagram showing an example of the 1st Null depth before execution of Self-Healing for each fault location of sample numbers 5 to 10 when the number of faults in the TRX is two. [Figure 55] 1 is a circuit diagram showing an example of a circuit configuration of a wireless communication device; [Figure 56] 1 is a flow diagram showing an example of a schematic operation flow of a wireless communication device. [Figure 57] 1 is a circuit diagram showing an example of a circuit configuration of a wireless communication system; [Figure 58] FIG. 11 is a block diagram showing an example of the hardware configuration of a computer that realizes a part of the functions of the wireless communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] 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.

[0047] <Embodiment 1> First, a description will be given of the configuration of the AAS 100 according to the first embodiment. An example of the circuit configuration of the AAS 100 according to the first embodiment is shown in FIG.

[0048] As shown in Fig. 21, the AAS100 according to the first embodiment has a similar configuration to the AAS900 according to the related art. Also, like the AAS900, the AAS100 can be incorporated as a component of the AP400 in the wireless communication system shown in Fig. 3. However, the AAS100 operates differently from the AAS900.

[0049] As described above, it has been confirmed that the variation in the 1st Null depth increases significantly as the number of failures of the TRX31-n increases in the AAS900 according to the related art. Therefore, even if only a few of the total 32 TRX31-n fail, if the failures are left unchecked, the DL SINR will be significantly degraded during spatial multiplexing, and the spatial multiplexing performance will be significantly degraded accordingly.

[0050] In contrast, the AAS 100 according to the first embodiment does not leave the failed TRX 31-n unattended when performing Massive MIMO / spatial multiplexing, but executes detection of the failed TRX 31-n. Specifically, the AAS 100 detects the failed TRX 31-n based on the amplitude or phase of the DL CAL signal output from the TX in each TRX 31-n to the CAL-TRX 51 in DL CAL operation, and the amplitude or phase of the UL CAL signal output from the RX in each TRX 31-n to the BB unit 20 in UL CAL operation.

[0051] Then, the AAS 100 stops transmission and reception on the failed TRX 31-n, and then performs self-healing to reconstruct the DL BFW using only the normal TRX 31-n. Specifically, the AAS 100 derives a DL transmission path matrix (= UL transmission path matrix) based on the reception of an SRS (Sounding Reference Signal) from the UE, assigns 0 (zero) to the propagation path matrix element of the failed TRX 31-n, and then performs ZF (Zero-Forcing) processing to derive a new DL BFW. The ZF processing will be described later.

[0052] This enables the AAS 100 to maintain the null depth in the directions of UEs other than the desired UE, and autonomously restore the spatial multiplexing performance.

[0053] It is assumed that the above-mentioned operations of the AAS 100 are performed by the BB unit 20. In addition, among the operations of the AAS 100 described below, operations that do not specify an operating entity are also assumed to be performed by the BB unit 20.

[0054] Hereinafter, the number of faults in the TRX31-n in an actual outdoor environment and the self-healing process by the AAS100 according to the first embodiment will be described based on actual measurements and simulations. First, in order to explain the self-healing process by the AAS 100 according to the first embodiment, a result of a statistical characteristic evaluation performed by simulation in a case where a plurality of UEs are arranged in various locations will be explained.

[0055] As an outdoor actual environment assumed in the simulation, an experimental system was constructed in the outdoor actual environment shown in Fig. 22. Note that Fig. 22 is a plan view of the AAS 100 and the UE as viewed from above.

[0056] In Fig. 22, the UE is moved linearly at a constant walking speed in front of the AAS 100 while being spaced apart. Then, SRS is transmitted from the UE at positions corresponding to UE#0, UE#1, and UE#2, and the SRS is received by all RXs of the AAS 100 (32 RXs under normal conditions). Then, based on the SRS reception result, the UL SRS channel estimation value in the outdoor actual environment shown in Fig. 22, that is, H corresponding to the DL transmission path matrix in the case of TDD (Time Division Duplex), is calculated. k was actually measured.

[0057] It was also assumed that UE#0, UE#1, and UE#2 were placed at equal angular intervals from the AAS100 (in this explanation, DL / UL transmission between the AAS100 and each of the three UEs was assumed at intervals of 0°±14°). Based on the knowledge obtained from Figs. 17 to 20, the fault locations showing the worst 1st Null depth for each number of faults in TRX31-n were selected, and the SRS reception data at the selected fault locations was zeroed out (i.e., zero was substituted for the propagation path matrix element of the fault location). This created a pseudo arrangement situation for faulty TRX31-n.

[0058] Then, ZF processing is performed using only the remaining normal SRS reception data of TRX31-n, and the DL BFW (W ZF ) was recalculated to confirm the degree of improvement in null depth due to Self-Healing.

[0059] The above-mentioned pseudo self-healing process will now be described in more detail. First, the above-mentioned pseudo Self-Healing process will be described with reference to the image diagrams of Figs. FIG. 23 is an image diagram showing the process up to the calculation of each UL channel estimation value between the AAS 100 and each of the three UEs 0, 1, and 2. In FIG. As shown in Fig. 23, while moving the UE linearly in front of the AAS 100, the UE transmits an SRS at positions corresponding to three UEs UE#0, UE#1, and UE#2, and the SRS is received by all RXs of the AAS 100. Then, based on the reception result of the SRS, each UL channel estimation value between the AAS 100 and each of the three UEs UE#0, UE#1, and UE#2 is calculated in advance. Thereafter, the calculated UL channel estimation value is used as each DL transmission path matrix between the AAS 100 and each of the three UEs UE#0, UE#1, and UE#2.

[0060] FIG. 24 shows a state in which three UEs, UE #0, UE #1, and UE #2, are spatially multiplexed when all 32 TRXs 31-n in the AAS 100 are functioning normally.

[0061] As shown in Fig. 24, the radiation pattern of the DL signal radiated to UE#1 has deep nulls in the directions of UE#0 and UE#2, and it can be seen that interference to UE#0 and UE#2 is avoided. Therefore, the DL SINR of each of the three UE#0, UE#1, and UE#2 is ensured.

[0062] FIG. 25 shows a situation in which three UEs, UE #0, UE #1, and UE #2, are spatially multiplexed before and after the execution of the self-healing process in the event of a failure in TRX31-n in the AAS100.

[0063] As shown in Figure 25, if the Self-Healing process is not performed, the radiation pattern of the DL signal radiated to UE#1 will have a null shift in the direction of UE#0 and UE#2, and only shallow nulls will be formed in the direction of UE#0 and UE#2.

[0064] In contrast, if self-healing processing is performed, ZF processing is performed using only the remaining normal SRS reception data of TRX31-n, and the DL BFW for 3-way spatial multiplexing is recalculated, it can be seen that the radiation pattern of the DL signal radiated to UE#1 once again has a deep null in the direction of UE#0 and UE#2.

[0065] Next, the above-mentioned pseudo self-healing process will be described with reference to the flow diagram of Fig. 26. In Fig. 26, it is assumed that each UL channel estimation value between the AAS 100 and each of the three UEs 0, 1, and 2 has already been calculated based on actual measurements.

[0066] As shown in FIG. 26, first, the AAS 100 stores the UL channel estimation values ​​calculated for each of the three UEs UE#0, UE#1, and UE#2 (step S11). Next, the AAS 100 adds AWGN (Additive White Gaussian Noise) equivalent to an error in the propagation path estimation to the UL channel estimation value of each of the three UEs UE#0, UE#1, and UE#2 as an SNR of 20 dB (step S12).

[0067] Next, the AAS100 detects the failed TRX31-n based on the amplitude or phase of the DL CAL signal output from the TX in each TRX31-n in DL CAL operation, and the amplitude or phase of the UL CAL signal output from the RX in each TRX31-n in UL CAL operation. Next, the AAS100 zeroes out the UL channel estimate of the failed TRX31-n (i.e., zeroes out the matrix elements of the failed TRX31-n in the UL propagation path matrix) and reduces the matrix elements of the UL propagation path matrix by substituting / setting them with zero. Next, the AAS100 reduces the UL propagation path matrix H k Next, AAS100 reconstructs H k The singular value decomposition of the matrix is ​​performed, and the generalized inverse matrix of the matrix consisting of the right singular vectors is defined as a new DL BFW(W ZF ) (step S13).

[0068] Next, the AAS 100 zeroes out the matrix elements of the failed TRX 31-n and converts the UL channel estimates into a DL channel matrix H k (step S14) to create a new DL BFW(W ZF ) (step S15). Next, the AAS100 calculates the DL SINR of the two-layer DL signal to each of the three UEs, UE#0, UE#1, and UE#2. The DL SINR can be calculated as the ratio of the desired wave S radiated toward each UE to the interference wave component "I" that is generated due to the deterioration of the null accuracy (null depth, null direction) created in each UE direction and is included in the radiation pattern generated toward the other two UEs. Next, the AAS100 calculates the total channel capacity [bps / Hz] that can be transmitted in two layers to each of the three UEs, UE#0, UE#1, and UE#2, using the Shannon theorem (C=B×Log2 1+S / N) (step S16). This quantitatively evaluates the improvement and effectiveness of the spatial multiplexing performance by the Self-Healing function when the TRX31-n fails. The B bandwidth substituted into the Shannon theorem is 100MHz. In addition, the distance between the AAS100 and each of the three UEs, UE#0, UE#1, and UE#2, is set to several tens of meters in this case, so the S / N ratio is high. Therefore, the DL SINR is not dominated by thermal noise "N", but by interference "I" from the radiation pattern to other UEs during spatial multiplexing, and is determined predominantly by the SIR according to the null depth in particular. Therefore, the transmission capacity C to each UE (unit is [bps / Hz], normalized at 1 Hz) was obtained by calculating and substituting the SIR.

[0069] 26 are performed to verify the pseudo self-healing process described above, and are unnecessary in the actual self-healing process. The details of the verification results obtained in steps S14 to S16 will be described later.

[0070] Next, the above-mentioned pseudo self-healing process will be described with reference to the schematic diagram of Fig. 27. Fig. 27 shows the DL channel matrix (=UL channel matrix) H k FIG. 27 shows the DL BFW(W ZF) is used to transmit DL signals, and UE#k extracts the DL signals of two layers.

[0071] In FIG. 27, H k is the [2×32] UL channel matrix for UE#k. H k is equivalent to the DL channel matrix due to the reciprocity of transmission and reception by TDD. TIFF2025021517000002.tif78 shows the adjoint matrix (Hermitian transpose) of A.

[0072] H k By singular value decomposition, we obtain the following equation. TIFF2025021517000003.tif889 where U k , Σ k , V k are as follows, respectively. U k :H k This is a [2 × 2] matrix obtained by singular value decomposition of the above. It is also a left singular matrix. V k :H k This is a [32 × 32] matrix obtained by singular value decomposition of the above. It is also a right singular matrix. Σ k :H k is a [2 × 32] matrix obtained by singular value decomposition of TIFF2025021517000004.tif1566, where λ k0 ,λ k1 is a singular value.

[0073] Furthermore, to separate the DL signals for the eight UEs, a matrix V all Considering [32×16], the formula is as follows. TIFF2025021517000005.tif8139 where v k0 , v k1 is a right singular vector of UE#k (two right singular vectors for two layers).

[0074] And, DL BFW(W ZF ) is expressed as follows: This is the generalized inverse matrix of TIFF2025021517000006.tif712. TIFF2025021517000007.tif11111Where, W ZF is a [32x16] matrix. The 16 in the column means 8UE x 2 layers = 16.

[0075] That is, in the first embodiment, DL BFW(W ZF ) is calculated by performing singular value decomposition on the DL propagation path matrix (=UL propagation path matrix) in which the matrix elements of the failed TRX31-n are zeroed out, and the generalized inverse matrix of the matrix consisting of the obtained right singular vectors is called DL BFW(W ZF )

[0076] Here, the weighting matrix by which the DL signal of UE#k is multiplied is given by the following equation. TIFF2025021517000008.tif19129In equation (4), the [] indicates that only the kth k And the rest is 0 i It becomes. However, E k , 0 i are expressed by the following equations, respectively. TIFF2025021517000009.tif1273

[0077] Therefore, If you use TIFF2025021517000010.tif7137, Only TIFF2025021517000011.tif794 is E k And other W ZF The parts where the components are multiplied become 0.

[0078] That is, DL channel matrix H k The signal received by UE#k is λ k0 ,λ k1 The result is only a two-layer DL signal to UE#k multiplied by This completes spatial multiplexing. In terms of physical meaning, this is equivalent to avoiding interference between radiation patterns of multiple UEs by forming a deep null in the layer direction of other UEs in the DL radiation pattern to UE#k, and forming a deep null in the UE#k direction in the radiation pattern to other UEs.

[0079] The effects of the AAS 100 according to the first embodiment will be described below. First, Fig. 28 to Fig. 30 show examples of radiation patterns of DL signals radiated from AAS100 to each of three UE#0, UE#1, and UE#2 when all 32 TRX31-n are normal. Fig. 28 to Fig. 30 show examples of radiation patterns of ±45° polarization transmitted through two layers (layer 0 and layer 1) as radiation patterns of DL signals radiated from AAS100 to UE#0 / UE#1 / UE#2 in the +14° / 0° / -14° directions, respectively. In Fig. 28 to Fig. 30, the horizontal axis indicates the horizontal angle as seen from AAS100, and the vertical axis indicates the radiation level. In Fig. 28 to Fig. 30, the horizontal angle in the direction of the other two UEs is shown by a dashed auxiliary line to clearly show the result of forming a null in the direction of the other two UEs. FIG. 31 also shows an example of the two-layer average DL SINR and total transmission capacity C of the DL signal to each of the three UEs, UE #0, UE #1, and UE #2, when all 32 TRXs 31-n are normal.

[0080] Next, Fig. 32 to Fig. 34 show examples of the 2-layer average DL SINR and total transmission capacity C of the DL signal to each of three UEs UE #0, UE #1, and UE #2 before and after performing self-healing when the number of faults in TRX 31-n is 3 / 6 / 12, respectively. Note that, when calculating Fig. 32 to Fig. 34, the fault location of TRX 31-n was selected as the fault location at which the 1st Null depth calculated for each of 1000 fault locations of TRX 31-n was the worst value (shallowest).

[0081] FIG. 35 shows an example of the fault location where the 1st Null depth is the worst value when the number of faults in TRX31-n is three. In FIG. 35, the diagonally hatched portion shows the fault location of TRX31-n (the same applies to the following FIG. 38 and FIG. 41). FIG. 36 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 in the +14° direction when three UE#0, UE#1, and UE#2 are spatially multiplexed after Self-Healing is performed with the fault location of TRX31-n in the state of FIG. 35. FIG. 37 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 after Self-Healing is performed with the fault location of TRX31-n in the state of FIG. 35. FIG. 37 shows an example of the radiation pattern of the ±45° polarization that transmits two layers (layer 0 and layer 1) as the radiation pattern of the DL signal radiated to UE#0. In addition, in Fig. 37, the horizontal angles in the direction of UE#1 (0° direction from AAS100) and the direction of UE#2 (-14° direction from AAS100) are indicated by dashed auxiliary lines to clearly show the results of forming nulls in the directions of UE#1 and UE#2 (the same applies to the following Figs. 40, 43 to 46). The horizontal and vertical axes in Fig. 37 are the same as those in Figs. 28 to 30 (the same applies to the following Figs. 40, 43 to 46).

[0082] Similarly, Fig. 38 shows an example of the fault location where the 1st Null depth is the worst value when the number of faults in TRX31-n is six. Fig. 39 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 in the +14° direction when three UE#0, UE#1, and UE#2 are spatially multiplexed after Self-Healing is performed with the fault location of TRX31-n in the state of Fig. 38. Fig. 40 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 after Self-Healing is performed with the fault location of TRX31-n in the state of Fig. 38.

[0083] Similarly, Fig. 41 shows an example of the fault location where the 1st Null depth is the worst value when the number of faults in TRX31-n is 12. Fig. 42 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 in the +14° direction when three UE#0, UE#1, and UE#2 are spatially multiplexed after Self-Healing is performed with the fault location of TRX31-n in the state of Fig. 41. Fig. 43 shows an example of the radiation pattern of the DL signal radiated from AAS100 to UE#0 after Self-Healing is performed with the fault location of TRX31-n in the state of Fig. 41.

[0084] As shown in Figures 28 to 30 and Figures 35 to 43, even when the number of faulty TRX31-n is 3 / 6 / 12, respectively, it can be seen that the null depth from UE#0 to UE#1 / #2 approaches the null depth when all 32 TRX31-n are normal due to the effect of Self-Healing. Also, as shown in Figures 31 to 34, even when the number of faulty TRX31-n is 3 / 6 / 12, respectively, it can be seen that the DL SINR and total transmission capacity C after Self-Healing is performed approaches the spatial multiplexing performance when all 32 TRX31-n are normal, compared to the state before Self-Healing is performed in which the TRX31-n faults are left unattended.

[0085] Furthermore, in the following, as a representative example, a case where the number of faulty TRX31-n is 12 is taken as an example, and the radiation pattern of the DL signal radiated from the AAS100 to the UE#0 before and after Self-Healing is performed is compared with the radiation pattern of the DL signal radiated from the AAS100 to the UE#0 when all 32 TRX31-n are normal. FIG. 44 shows an example of the radiation pattern of the DL signal radiated from the AAS100 to the UE#0 when all 32 TRX31-n are normal. FIG. 45 shows an example of the radiation pattern of the DL signal radiated from the AAS100 to the UE#0 before Self-Healing is performed when the number of faulty TRX31-n is 12. FIG. 46 shows an example of the radiation pattern of the DL signal radiated from the AAS100 to the UE#0 after Self-Healing is performed when the number of faulty TRX31-n is 12.

[0086] As shown in Figures 44 to 46, even though 12 of the total 32 TRX31-n are faulty, it can be seen that the null depth in the direction from UE#0 to UE#1 and UE#2 has been improved due to the effect of self-healing.

[0087] Although not shown, the null depth in the direction of the other two UEs is also improved for UE#1 and UE#2. Therefore, as shown in Fig. 31 and Fig. 34, compared with the state before Self-Healing in which the failures of 12 TRX31-n were left unattended, the DL SINR and total transmission capacity C after Self-Healing is performed have approached the spatial multiplexing performance of all 32 TRX31-n when they are normal, and it can be seen that the spatial multiplexing performance has been restored.

[0088] Next, further analysis was performed based on the analysis results of the effect of Self-Healing in Figures 28 to 46. Figure 47 shows an example in which the average DL SINR of three UEs UE#0, UE#1, and UE#2 before and after Self-Healing is performed is compared with the average DL SINR when all 32 TRXs 31-n are normal when the number of faulty TRXs 31-n is 3 / 6 / 12 / 18 / 24 respectively. Also, Figure 48 shows an example in which the average transmission capacity of three UEs UE#0, UE#1, and UE#2 before and after Self-Healing is performed is compared with the average transmission capacity when all 32 TRXs 31-n are normal when the number of faulty TRXs 31-n is 3 / 6 / 12 / 18 / 24 respectively. FIG. 49 shows an example of average power loss of three UEs UE#0, UE#1, and UE#2 before and after Self-Healing when the number of faulty TRXs 31-n is 3 / 6 / 12 / 18 / 24 respectively. The power loss is defined as the decrease in transmission power consumed for forming a null by Self-Healing. In other words, the power loss is defined as the decrease in the radiation level of the main lobe from when all 32 TRXs 31-n are normal. In addition, in FIG. 47 to FIG. 49, the values ​​when the number of faulty TRXs 31-n is 3 / 6 / 12 / 18 respectively indicate the values ​​at the fault positions where the 1st Null depth is the worst value. In addition, the values ​​when the number of faulty TRXs 31-n is 24 indicate the values ​​at the fault positions where the 1st Null depth is the worst value and the values ​​at the fault positions where the 1st Null depth is the best value.

[0089] As shown in FIG. 47 and FIG. 48, assuming that the AAS100 has a total of 64 antenna elements and a total of 32 TRX31-n, if the number of failures of the TRX31-n is up to about 6, it can be seen that the effect of Self-Healing allows all 32 TRX31-n to achieve spatial multiplexing performance equivalent to that in normal conditions. Also, if the number of failures of the TRX31-n is up to about 12, it can be seen that the effect of Self-Healing allows a deep null to be formed in the direction of other UEs. Also, as shown in FIG. 49, if the number of failures of the TRX31-n is up to about 12, the power loss consumed in forming the null can be suppressed to about -3 dB. However, if the number of failures of the TRX31-n is 18 or more, the power loss consumed in forming the null increases to about -7 dB, and the DL reach of the main lobe is reduced to about 45% of that when all 32 TRX31-n are normal, and is significantly degraded to less than 50%. When this is converted into a coverage area, the coverage area is 0.2 (≒ 0.45 2 ), that is, reduced to 20%. In this state, even if spatial multiplexing performance can be achieved by using nulls, the coverage area will not be sufficient for operation, so it is clear that this is an unacceptable situation and is not a perfect way to restore spatial multiplexing performance.

[0090] However, it can be seen that the spatial multiplexing performance can be largely restored and maintained by performing self-healing rather than leaving the failure of TRX31-n as it is. From this point of view, it can be said that FIG. 49 shows the effectiveness of the present disclosure.

[0091] As described above, the AAS 100 according to the first embodiment detects a failed TRX 31-n among the TRXs 31-n in the AAS 100. Specifically, the AAS 100 detects the failed TRX 31-n based on the amplitude or phase of the DL CAL signal output from the TX in each TRX 31-n to the CAL-TRX 51 in DL CAL operation, and the amplitude or phase of the UL CAL signal output from the RX in each TRX 31-n to the BB unit 20 in UL CAL operation.

[0092] Then, the AAS 100 stops transmission and reception in the failed TRX 31-n, and executes self-healing to reconstruct the DL BFW using only the normal TRX 31-n. Specifically, the AAS 100 derives a UL transmission channel matrix (= DL transmission channel matrix) based on the SRS received from the UE, and substitutes zero for the propagation channel matrix elements of the failed TRX 31-n. The AAS 100 then performs singular value decomposition on the UL transmission channel matrix (= DL transmission channel matrix) by ZF processing, and derives a generalized inverse matrix of a matrix composed of right singular vectors as a new DL BFW to be reconstructed.

[0093] Therefore, even if a failure occurs in a TRX31-n, the AAS100 can maintain the null depth in the direction of UEs other than the desired UE by performing self-healing using a normal TRX31-n other than the failed TRX31-n. This allows the spatial multiplexing performance of the AAS100 to be maintained, allowing the AAS100 to continue operating.

[0094] In addition, even if a failure occurs in the TRX31-n, the AAS100 can maintain its spatial multiplexing performance and continue operation. This allows planned maintenance and repairs of the AAS100, which can contribute to reducing CAPEX (Capital Expenditure) and OPEX (Operating Expense).

[0095] Next, a modification of the first embodiment will be described below. (A) Variation 1 First, the first modification will be described. In spatial multiplexing and massive-MIMO operation, the AAS 100 substitutes zero for the channel matrix elements of the failed TRX 31-n and then performs ZF processing to reconstruct the DL BFW. Here, the ZF processing places the highest priority on maintaining the null depth.

[0096] Therefore, as explained with reference to Fig. 49, when the number of faulty TRX31-n in the AAS100 becomes 18 or more, the power loss consumed for forming the null increases to about -7 dB, causing the DL reach of the mainlobe to deteriorate significantly to 50% or less, and the coverage area to be reduced to 20%. As a result, there is a possibility that a dead zone where signals cannot be transmitted or received will occur between the AAS100 and the UE.

[0097] Therefore, in the first modification, in order to avoid the occurrence of a dead zone between the AAS 100 and the UE, the AAS 100 judges whether or not to execute self-healing based on the number of faults in the TRX 31-n. At this time, for example, the AAS 100 uses the maximum rating of -3 dB (50%) specified in 3GPP (registered trademark) and the Radio Law in Japan as a judgment criterion.

[0098] That is, the AAS100 calculates in advance the power loss consumed to form a null for each number of faults in TRX31-n, and derives in advance an upper limit value of the number of faults at which the power loss can be maintained within -3 dB as a threshold (in the example of FIG. 49, the threshold is 12). Then, if the number of faults in TRX31-n is equal to or less than the threshold, the AAS100 decides to execute self-healing. On the other hand, if the number of faults in TRX31-n exceeds the threshold, the AAS100 decides not to execute (stop) self-healing. In this case, the AAS100 may also issue an alarm to have the AAS100 repaired.

[0099] (B) Variation 2 Next, the second modification will be described. In the second modification, whether or not to execute self-healing is determined based on the number and locations of faults in the TRX31-n.

[0100] First, an example in which one TRX31-n has a fault will be described. Fig. 50 shows an example of the arrangement of antenna elements constituting antenna 40. Fig. 50 corresponds to either the -45° polarized antenna or the +45° polarized antenna shown in Figs.

[0101] In Fig. 50, a total of 32 antenna elements are arranged, 8 in the horizontal direction and 4 in the vertical direction. In addition, two vertical antenna elements are grouped, and the two grouped antenna elements are connected to one TRX31-n. In addition, column numbers are assigned in the horizontal direction. In the following, for example, a column with column number 0 will be referred to as column 0.

[0102] FIG. 51 shows an example of comparing the radiation pattern of the DL signal radiated from the AAS100 to the UE before Self-Healing is performed for each failure location when there is one faulty TRX31-n, with the radiation pattern of the DL signal radiated from the AAS100 to the UE when all 32 TRX31-n are normal. FIG. 51 shows the radiation pattern when one TRX31-n connected to the antenna elements in columns 0 / 1 / 2 / 3 fails. In FIG. 51, the 1st null depth required for spatial multiplexing of 8 UEs x 2 layers = 16 layers is assumed to be 33 dB. In FIG. 51, the horizontal axis indicates the horizontal angle as seen from the AAS100, and the vertical axis indicates EIRP.

[0103] As shown in Fig. 51, when one TRX31-n connected to antenna elements in column 0 / 3 fails, the 1st Null depth (33 dB) required for 16-layer spatial multiplexing can be maintained even before Self-Healing is executed. On the other hand, when one TRX31-n connected to antenna elements in column 1 / 2 fails, the 1st Null depth (33 dB) required for 16-layer spatial multiplexing cannot be maintained.

[0104] FIG. 52 shows an example in which the horizontal axis represents the column number of the fault location and the vertical axis represents the 1st Null depth before Self-Healing is performed for each column number when there is one fault in TRX31-n. As shown in Figure 52, when one TRX31-n connected to the antenna elements of columns 0 / 3 / 4 / 7 fails, the 1st Null depth (33 dB) required for 16-layer spatial multiplexing can be maintained. In other words, in this case, stable spatial multiplexing performance can be maintained without performing Self-Healing.

[0105] On the other hand, if one TRX31-n connected to the antenna elements of columns 1 / 2 / 5 / 6 fails, the 1st null depth (33 dB) required for 16-layer spatial multiplexing cannot be maintained. Therefore, it is necessary to improve spatial multiplexing performance by implementing self-healing.

[0106] Therefore, when the number of faults in TRX31-n is 1, the AAS100 pre-stores the positions connected to the antenna elements in columns 1 / 2 / 5 / 6 as the fault positions at which Self-Healing should be performed. When the number of faults in TRX31-n is 1, the AAS100 determines to perform Self-Healing if the fault position of TRX31-n matches the pre-stored position, and determines not to perform Self-Healing in other cases.

[0107] Alternatively, the AAS100 pre-stores the positions connected to the antenna elements in columns 0, 3, 4, and 7 as the fault positions at which Self-Healing will not be performed when the number of faults in TRX31-n is 1. Then, when the number of faults in TRX31-n is 1, if the fault position of TRX31-n matches any of the pre-stored positions, the AAS100 determines not to perform Self-Healing, and otherwise determines to perform Self-Healing.

[0108] Next, an example in which the number of faulty TRX31-n is two will be described. Here, when the number of faults in TRX31-n is two, 1000 fault locations of TRX31-n are randomly selected, and the 1st Null depth before Self-Healing is executed is calculated for each of the 1000 fault locations. Then, 10 sample fault locations are extracted in order of shallowest 1st Null depth. Of the 10 samples, the fault location of sample number 1 has the shallowest 1st Null depth, and the 1st Null depth becomes deeper as the sample number increases.

[0109] FIG. 53 shows an example of the 1st Null depth before Self-Healing is performed for each of the fault locations of sample numbers 1 to 4 when the number of faults in TRX31-n is two. FIG. 53 also shows an example of the radiation pattern of the DL signal when the fault locations are sample numbers 1 and 2. FIG. 54 shows an example of the 1st Null depth before Self-Healing is performed for each of the fault locations of sample numbers 5 to 10 when the number of faults in TRX31-n is two. FIG. 54 also shows an example of the radiation pattern of the DL signal when the fault location is sample number 9. In FIG. 53 and FIG. 54, the diagonally hatched portion indicates the fault location of TRX31-n. The horizontal and vertical axes of the radiation pattern of the DL signal are the same as those in FIG. 51.

[0110] As shown in Fig. 53, in sample numbers 1 to 4, the TRX31-n connected to the antenna elements in the 0 / 1 / 2 / 5 / 6 / 7 rows, which are shifted left or right from the 3 / 4 row near the horizontal center, has failed, and the position of the failed TRX31-n is biased to either the left or right. In addition, in sample numbers 1 to 4, the 1st Null depth is shallow, and it is necessary to improve the spatial multiplexing performance by executing Self-Healing.

[0111] On the other hand, in sample numbers 5 to 10, the TRX31-n connected to the antenna elements in 3 / 4 rows near the horizontal center is faulty, or the position of the faulty TRX31-n is not biased to the left or right. Also, sample numbers 5 to 10 have a deeper 1st null depth than sample numbers 1 to 4, and can maintain stable spatial multiplexing performance.

[0112] Therefore, when the number of faults in TRX31-n is two, AAS100 pre-stores the fault locations of sample numbers 1 to 4 as the fault locations at which Self-Healing should be performed. When the number of faults in TRX31-n is two and the fault location of TRX31-n matches any of the pre-stored locations, AAS100 determines to perform Self-Healing, and in other cases determines not to perform Self-Healing.

[0113] (C) Variation 3 Next, a third modification will be described. In the third modification, a part of the processing that was performed by the AAS 100 is performed by the DU 200 . The AAS 100 detects a faulty TRX 31-n and notifies the DU 200 of the number of faults in the TRX 31-n, the fault locations, etc., via a multi-core multimode optical fiber (optical fronthaul). The AAS 100 also transfers the SRS received from the UE to the DU 200 via the multi-core multimode optical fiber (optical fronthaul).

[0114] The DU200 stops transmission and reception in the failed TRX31-n, and then performs self-healing to reconstruct the DL BFW using only the normal TRX31-n. Specifically, the DU200 derives a UL transmission channel matrix (= DL transmission channel matrix) based on the SRS received from the UE, and substitutes zero for the propagation channel matrix elements of the failed TRX31-n. The DU200 then performs singular value decomposition on the UL transmission channel matrix (= DL transmission channel matrix) by ZF processing, and derives the generalized inverse matrix of the matrix composed of right singular vectors as a new DL BFW to be reconstructed.

[0115] The DU200 multiplies the DL signal finally radiated from the antenna 40 in the AAS100 to the two layers of each UE by the reconstructed DL BFW, and transmits the DL signal multiplied by the DL BFW to the AAS100 via a multi-core multimode optical fiber (optical fronthaul).

[0116] Alternatively, the DU 200 notifies the AAS 100 of the reconstructed DL BFW via a multi-core multimode optical fiber (optical fronthaul). The AAS 100 finally multiplies the DL signal radiated from the antenna 40 to the two layers of each UE by the reconstructed DL BFW.

[0117] <Embodiment 2> The second embodiment corresponds to an embodiment that conceptually illustrates the first embodiment described above. First, the configuration of the wireless communication device 100A according to the second embodiment will be described. Fig. 55 shows an example of a circuit configuration of the wireless communication device 100A according to the second embodiment. Note that the wireless communication device 100A corresponds to the AAS 100 of the first embodiment described above. Also, in Fig. 55, it is assumed that the wireless communication device 100A is used as a base station.

[0118] 55, the wireless communication device 100A according to the second embodiment includes a control unit 21, m (m is an integer equal to or greater than 2) transceivers (TRX) 31-1 to 31-m, and a calibration transceiver (CAL-TRX) 51. In the following, when it is not necessary to specify which TRX 31-1 to 31-m it is, it will be appropriately referred to as TRX 31-n (n=1, . . . , m).

[0119] The control unit 21 corresponds to the BB unit 20 in the above-mentioned first embodiment. The control unit 21 controls a downlink calibration (DL CAL) operation and an uplink calibration (UL CAL) operation.

[0120] In DL CAL operation, a downlink calibration (DL CAL) signal is output from the control unit 21 to each of the m TRXs 31-n, output from each of the m TRXs 31-n to the CAL-TRX 51, and output from the CAL-TRX 51 to the control unit 21.

[0121] In UL CAL operation, an uplink calibration (UL CAL) signal is output from the control unit 21 to the CAL-TRX 51, output from the CAL-TRX 51 to each of the m TRXs 31-n, and output from each of the m TRXs 31-n to the control unit 21.

[0122] The control unit 21 includes a failure detection unit 211 and a reconstruction unit 212 . The failure detection unit 211 detects a failure in each of the m TRX31-n based on the DL CAL signal output from each of the m TRX31-n to the CAL-TRX51 in DL CAL operation and the UL CAL signal output from each of the m TRX31-n to the control unit 21 in UL CAL operation.

[0123] The reconstructing unit 212 executes a self-healing process of reconstructing a downlink beamforming weight (DL BFW) for spatial multiplexing using TRX31-n other than the failed TRX31-n among the m TRX31-n.

[0124] Here, a description will be given of the flow of operation of the wireless communication device 100A according to the present embodiment 2. Fig. 56 shows an example of a schematic flow of operation of the wireless communication device 100A according to the present embodiment 2.

[0125] As shown in FIG. 56, the failure detection unit 211 detects a failure in each of the m TRX31-n based on the DL CAL signal output from each of the m TRX31-n to the CAL-TRX51 in DL CAL operation and the UL CAL signal output from each of the m TRX31-n to the control unit 21 in UL CAL operation (step S21).

[0126] The reconstructing unit 212 executes a self-healing process of reconstructing the DL BFW for spatial multiplexing by using the TRXs 31-n other than the failed TRX 31-n among the m TRXs 31-n (step S22).

[0127] Therefore, even if a failure occurs in a TRX 31-n, the wireless communication device 100A can reconstruct the DL BFW for spatial multiplexing by executing a self-healing process using a TRX 31-n other than the failed TRX 31-n. This allows the wireless communication device 100A to maintain the null depth in the direction of UEs other than the desired UE, thereby maintaining spatial multiplexing performance.

[0128] The failure detection unit 211 may detect a failure of each of the m TRX31-n based on the phase or amplitude of the DL CAL signal output from each of the m TRX31-n to the CAL-TRX51 in DL CAL operation, and the phase or amplitude of the UL CAL signal output from each of the m TRX31-n to the control unit 21 in UL CAL operation. For example, the failure detection unit 211 may calculate an average value of the phase or amplitude of the DL CAL signal (or UL CAL signal) output from the m TRX31-n, and determine that a TRX31-n whose difference from the average value is equal to or greater than a threshold value is faulty.

[0129] In addition, the reconstructing unit 212 may substitute zero for the matrix elements of the propagation path matrix representing the propagation path between a terminal such as a UE, which corresponds to the failed TRX31-n, and perform zero-forcing (ZF) processing using the propagation path matrix, thereby reconstructing the DL BFW for spatial multiplexing.

[0130] In addition, in the ZF processing, the reconstruction unit 212 may perform singular value decomposition on the channel matrix in which zeros are substituted for the matrix elements of the failed TRX31-n, and derive a generalized inverse matrix of the matrix consisting of right singular vectors obtained by the singular value decomposition as the DL BFW for spatial multiplexing to be reconstructed.

[0131] The wireless communication device 100A may further include a first determination unit that determines whether or not the self-healing process can be executed based on the number of faults in the TRX 31-n. In this case, the reconstruction unit 212 executes the self-healing process when the first determination unit determines that the self-healing process can be executed.

[0132] The above-mentioned first determination unit may calculate in advance, for each number of faults in TRX31-n, a power loss indicating a difference between the transmission power of a transmission signal when spatial multiplexing is performed in a state where all m TRX31-n are normal and the transmission power of a transmission signal when spatial multiplexing is performed in the DL BFW for spatial multiplexing reconstructed by the Self-Healing process. The above-mentioned first determination unit may set in advance a threshold value for the number of faults in TRX31-n based on the power loss for each number of faults in TRX31-n. The above-mentioned first determination unit may determine whether or not to execute the Self-Healing process based on a result of comparing the number of faults in TRX31-n with the threshold value. Furthermore, the above-mentioned first determination unit may set, in advance, as a threshold, an upper limit on the number of faulty TRX31-n for which the power loss can be kept within a predetermined value.

[0133] The wireless communication device 100A may further include a second determination unit that determines whether or not the self-healing process can be executed based on the number of faults and the fault locations of the TRXs 31-n. In this case, the reconstruction unit 212 executes the self-healing process when the second determination unit determines that the self-healing process can be executed.

[0134] <Embodiment 3> The third embodiment corresponds to an embodiment in which some of the components included in the wireless communication device 100A in the second embodiment are provided in another wireless communication device. First, a description will be given of the configuration of a wireless communication system according to the present embodiment 3. Fig. 57 shows an example of a circuit configuration of a wireless communication system according to the present embodiment 3.

[0135] 57, the wireless communication system according to the third embodiment includes a first wireless communication device 100B and a second wireless communication device 100C. The first wireless communication device 100B corresponds to the AAS 100 of the first embodiment, and the second wireless communication device 100C corresponds to the DU 200 of the first embodiment.

[0136] The first wireless communication device 100B is different from the wireless communication device 100A of the above-mentioned second embodiment in that the reconstruction unit 212 is removed. The second wireless communication device 100C includes the reconstructing unit 212 described above.

[0137] In the third embodiment, the failure detection unit 211 in the first wireless communication device 100B detects a failed TRX 31-n, and notifies the reconstruction unit 212 in the second wireless communication device 100C of the number of failures in the TRX 31-n, the failure locations, etc. The reconstruction unit 212 in the second wireless communication device 100C executes a self-healing process similar to that in the second embodiment described above, based on the number of failures in the TRX 31-n, the failure locations, etc.

[0138] As described above, in the third embodiment, the installation position of the reconstruction unit 212 is different from that in the second embodiment, but the basic operation and effects are the same as those in the second embodiment. Therefore, the description of the operation and effects of the third embodiment will be omitted.

[0139] 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 a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. For example, each of the above-described embodiments can be appropriately combined with other embodiments.

[0140] In addition, some of the functions of the wireless communication device (including the AAS and the DU) according to the present disclosure can be realized by causing a processor such as a CPU (Central Processing Unit) to execute a program.

[0141] FIG. 58 illustrates an example of the hardware configuration of a computer 100D that realizes some of the functions of the wireless communication device according to the present disclosure. As shown in FIG. 58, a computer 100D includes a processor 81 and a memory 82.

[0142] 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.

[0143] 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).

[0144] A program is stored in the memory 82. When the program is loaded into the computer 100D, the program includes a set of instructions (or software code) for causing the computer 100D to perform some of the functions of the wireless communication devices according to the above-mentioned embodiments. The components of the wireless communication device 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 wireless communication device described above may be realized by the memory 82.

[0145] 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.

[0146] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; and a reconstruction unit that executes a self-healing process to reconstruct a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers. Wireless communication device. (Appendix 2) the failure detection unit detects a failure of each of the plurality of transceivers based on a phase or an amplitude of the downlink calibration signal output from each of the plurality of transceivers and a phase or an amplitude of the uplink calibration signal. 2. The wireless communication device of claim 1. (Appendix 3) The reconstruction unit is Substituting zero into the matrix elements of the failed transceiver among the matrix elements of a propagation path matrix representing a propagation path between the terminal and the failed transceiver; performing a zero-forcing process using the channel matrix in which zeros are substituted for matrix elements of the failed transceiver, thereby reconstructing the downlink beamforming weight for spatial multiplexing; 2. The wireless communication device of claim 1. (Appendix 4) the reconstruction unit performs singular value decomposition on the channel matrix in which zeros are substituted for matrix elements of the failed transceiver in the zero forcing process, and derives a generalized inverse matrix of a matrix consisting of right singular vectors obtained by the singular value decomposition as the downlink beamforming weight for spatial multiplexing to be reconstructed. 4. The wireless communication device of claim 3. (Appendix 5) Further comprising a first determination unit that determines whether or not the self-healing process is executable based on the number of faults in the transceiver. 2. The wireless communication device of claim 1. (Appendix 6) The first determination unit is Calculate in advance a power loss indicating a difference between a transmission power of a transmission signal when spatial multiplexing is performed in a state where all of the plurality of transceivers are normal and a transmission power of a transmission signal when spatial multiplexing is performed using a downlink beamforming weight for spatial multiplexing reconstructed by the self-healing process, for each failure number of the transceivers; setting a threshold value for the number of faults in the transceivers in advance based on the power loss for each fault in the transceivers; determining whether or not the self-healing process is executable based on a comparison result between the number of faults in the transceivers and the threshold value; 6. The wireless communication device of claim 5. (Appendix 7) The first determination unit pre-sets an upper limit of the number of faults in the transceivers at which the power loss can be maintained within a predetermined value as the threshold value. 7. The wireless communication device of claim 6. (Appendix 8) and a second determination unit that determines whether or not the self-healing process can be executed based on the number of faults and the fault locations of the transceivers. 2. The wireless communication device of claim 1. (Appendix 9) A wireless communication method for a wireless communication device including a plurality of transceivers, a calibration transceiver, and a control unit, comprising: a failure detection step of detecting a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; A reconfiguration step of performing a self-healing process to reconfigure a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers. A wireless communication method. (Appendix 10) a first wireless communication device; a second wireless communication device, The first wireless communication device, A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation, The second wireless communication device, a reconfiguration unit that executes a self-healing process to reconfigure a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers; Wireless communication system. [Explanation of symbols]

[0147] 10A,10B Optical Transceiver 20 Baseband (BB) section 21 Control section 211 Fault detection unit 212 Reconstruction Department 31-0~31-31,31-1~31-m Transceiver (TRX) 32-0~32-31 Switch (SW: Switch) 40 Antenna 51 Calibration transmitter / receiver (CAL-TRX) 52 Switch 60 Calibration Network (CAL Network) 81 Processor 82 Memory 100 Active Antenna System (AAS) 100A Wireless communication equipment 100B First wireless communication device 100C Second wireless communication device 100D Computer 200 Distributed Unit (DU) 300 Centralized base station (CU:Center Unit) 400 Access Point (AP) 500 Front hauls

Claims

1. A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; and a reconstruction unit that executes a self-healing process to reconstruct a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers. Wireless communication device.

2. the failure detection unit detects a failure of each of the plurality of transceivers based on a phase or an amplitude of the downlink calibration signal output from each of the plurality of transceivers and a phase or an amplitude of the uplink calibration signal. The wireless communication device of claim 1 .

3. The reconstruction unit is Substituting zero into the matrix elements of the failed transceiver among the matrix elements of a propagation path matrix representing a propagation path between the terminal and the failed transceiver; performing a zero-forcing process using the channel matrix in which zeros are substituted for matrix elements of the failed transceiver, thereby reconstructing the downlink beamforming weight for spatial multiplexing; The wireless communication device of claim 1 .

4. the reconstruction unit performs singular value decomposition on the channel matrix in which zeros are substituted for matrix elements of the failed transceiver in the zero forcing process, and derives a generalized inverse matrix of a matrix consisting of right singular vectors obtained by the singular value decomposition as the downlink beamforming weight for spatial multiplexing to be reconstructed. The wireless communication device according to claim 3 .

5. a first determination unit that determines whether or not the self-healing process can be executed based on the number of faults in the transceivers, The wireless communication device of claim 1 .

6. The first determination unit is Calculate in advance a power loss indicating a difference between a transmission power of a transmission signal when spatial multiplexing is performed in a state where all of the plurality of transceivers are normal and a transmission power of a transmission signal when spatial multiplexing is performed using a downlink beamforming weight for spatial multiplexing reconstructed by the self-healing process, for each failure number of the transceivers; setting a threshold value for the number of faults in the transceivers in advance based on the power loss for each fault in the transceivers; determining whether or not the self-healing process is executable based on a comparison result between the number of faults in the transceivers and the threshold value; 6. The wireless communication device according to claim 5.

7. the first determination unit presets an upper limit of the number of faults in the transceivers at which the power loss can be maintained within a predetermined value as the threshold value; 7. The wireless communication device according to claim 6.

8. a second determination unit that determines whether or not the self-healing process can be executed based on the number of faults and the locations of the faults in the transceivers, The wireless communication device of claim 1 .

9. A wireless communication method for a wireless communication device including a plurality of transceivers, a calibration transceiver, and a control unit, comprising: a failure detection step of detecting a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation; A reconfiguration step of performing a self-healing process to reconfigure a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers. A wireless communication method.

10. A first wireless communication device; a second wireless communication device, The first wireless communication device is A plurality of transceivers; A calibration transceiver; A control unit, The control unit is a failure detection unit that detects a failure in each of the plurality of transceivers based on a downlink calibration signal output from each of the plurality of transceivers to the calibration transceiver in a downlink calibration operation and an uplink calibration signal output from each of the plurality of transceivers to the control unit in an uplink calibration operation, The second wireless communication device is a reconfiguration unit that executes a self-healing process to reconfigure a downlink beamforming weight for spatial multiplexing by using a transceiver other than the failed transceiver among the plurality of transceivers; Wireless communication system.

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