CONTROL DEVICE, METHOD, AND PROGRAM

Abstract

To provide a control device, a method, and a program that can prevent the deterioration of desired effects expected in multiantenna communication in a radio access network configuration in which base station function groups for performing multiantenna communication are separately arranged in a plurality of communication devices.SOLUTION: A notification unit 31 in a control device 30 notifies a first communication device 10 of a "non-recommended matrix list." The "non-recommended matrix list" is a list containing information indicating "non-recommended precoding matrices" whose use is not recommended due to a "hardware configuration (hardware setting)" of a second communication device 20 out of a plurality of precoding matrices included in a "code book" available for precoding processing.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a control device, a method, and a program. [Background technology]

[0002] Multi-antenna technologies such as MIMO (Multiple Input Multi Output) are used in wireless base stations to improve user rates, increase system capacity, and expand coverage areas (for example, Patent Document 1). Examples of multi-antenna technologies include transmit diversity, precoding, beamforming, and spatial multiplexing. The wireless base station disclosed in Patent Document 1 executes beamforming processing and precoding processing.

[0003] In addition, the separation of radio base station functions into DU (Distributed Unit) and RU (Radio Unit) has been considered for 4G and 5G mobile communication systems. O-RAN (Open RAN (Radio Access Network)) fronthaul specifications are expected to promote the realization of multi-vendor RAN that enables the connection of DU and RU made by different vendors. The O-RAN (Open RAN) fronthaul specifications adopt a provision called Sprit Option 7-2X, which is a provision regarding the division of functions between O-DU (O-RAN Distributed Unit) and O-RU (O-RAN Radio Unit). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2015-521815 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in order for a radio base station to perform appropriate precoding control, the radio base station needs to acquire channel state information (CSI). For example, the radio base station transmits a reference signal. Then, the terminal estimates a channel state based on the received reference signal, and selects a suitable precoding matrix from among a plurality of precoding matrices (precoding weights) included in a codebook based on the estimated channel state. Then, the terminal feeds back an index of the selected precoding matrix to the radio base station as a Precoding Matrix Indicator (PMI). This PMI is a part of the CSI feedback information. Note that the codebook is held by both the radio base station and the terminal.

[0006] The present inventor found that among multiple precoding matrices included in the codebook, there may be a "non-recommended precoding matrix" whose use is not recommended due to the hardware configuration of the RU. For example, depending on the hardware configuration of the RU, when a non-recommended precoding matrix is ​​used, the desired effect expected from multi-antenna communication (e.g., the effect of transmit diversity, precoding, beamforming, and spatial multiplexing) may be reduced. Furthermore, feedback processing from the terminal to the DU is performed before an appropriate precoding matrix that takes into account the influence of the hardware configuration of the RU is selected, and this may result in avoidable processing (i.e., wasteful processing) by the terminal, the RU, and the DU.

[0007] An object of the present disclosure is to provide a control device, method, and program that can suppress a decrease in the desired effects expected from multi-antenna communication in a wireless access network configuration in which a group of base station functions for performing multi-antenna communication are separately arranged in multiple communication devices. [Means for solving the problem]

[0008] A control device according to a first aspect is a control device that controls a second communication device out of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged, The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including beamforming processing and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The control device includes a notification unit that notifies the first communication device of a non-recommended matrix list including information indicating non-recommended preceding matrices that are not recommended for use due to a hardware configuration of the second communication device, among a plurality of preceding matrices included in a codebook that can be used for the preceding process, or a recommended matrix list including information indicating recommended preceding matrices among the plurality of preceding matrices excluding the non-recommended preceding matrices.

[0009] The method according to the second aspect is a method executed by a control device that controls a second communication device of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged, the method comprising: The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including beamforming processing and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The method includes notifying the first communication device of a non-recommended matrix list including information indicating non-recommended precoding matrices that are not recommended for use due to a hardware configuration of the second communication device, among a plurality of precoding matrices included in a codebook that can be used for the precoding process, or a recommended matrix list including information indicating recommended precoding matrices among the plurality of precoding matrices excluding the non-recommended precoding matrices.

[0010] A program according to a third aspect is a program for causing a control device that controls a second communication device of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged to execute a predetermined process, The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including beamforming processing and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The specified processing includes notifying the first communication device of a non-recommended matrix list including information indicating non-recommended precoding matrices that are not recommended for use due to a hardware configuration of the second communication device, among a plurality of precoding matrices included in a codebook that can be used for the precoding processing, or a recommended matrix list including information indicating recommended precoding matrices among the plurality of precoding matrices excluding the non-recommended precoding matrices. Effect of the Invention

[0011] The present disclosure makes it possible to provide a control device, method, and program that can suppress a decrease in the desired effects expected from multi-antenna communication in a wireless access network configuration in which base station functions for performing multi-antenna communication are separately arranged in multiple communication devices. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of a communication system in a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of a control device in the first embodiment. [Diagram 3] FIG. 11 is a block diagram illustrating an example of a first communication device in a second embodiment. [Figure 4] FIG. 11 is a block diagram illustrating an example of a second communication device in the second embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment will be described with reference to the drawings. In the embodiments, the same or equivalent elements are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0014] First Embodiment <Communication System Overview> Fig. 1 is a diagram showing an example of a communication system in the first embodiment. In Fig. 1, a radio access network portion of the communication system is shown.

[0015] In FIG. 1, the communication system 1 includes a first communication device 10 and a second communication device 20. In the first communication device 10 and the second communication device 20, a base station function group for performing multi-antenna communication (for example, transmission diversity, MIMMO communication, etc.) with a terminal (not shown) is separately arranged. The first communication device 10 and the second communication device 20 are connected to each other via a front haul. That is, the first communication device 10 corresponds to a DU (Distributed Unit) of O-RAN in, for example, 4G and 5G, and the second communication device 20 corresponds to an RU (Radio Unit). Note that, although one each of the first communication device 10 and the second communication device 20 is shown here, the number of each communication device is not limited thereto. For example, a plurality of second communication devices 20 may be connected to one first communication device 10. In the following, a case where the functions are separated mainly based on Sprit Option 7-2X will be described as an example.

[0016] The first communication device 10 is a communication device that executes baseband processing (first signal processing) including precoding processing and corresponding to a higher physical layer. The second communication device 20 executes baseband processing (second signal processing) including digital beamforming processing and corresponding to a lower physical layer, and wireless processing that converts a baseband signal into a wireless signal. That is, here, O-RU and O-DU of Category A in Split Option 7-2X are assumed.

[0017] Here, the precoding matrix used in the precoding process may be a precoding matrix excluding a "non-recommended precoding matrix" included in a "non-recommended matrix list" described later among a plurality of precoding matrices included in the "codebook". Alternatively, the precoding matrix used in the precoding process may be a "recommended precoding matrix" included in a "recommended matrix list" described later. Alternatively, the precoding matrix used in the precoding process may be a precoding matrix excluding a "non-recommended precoding matrix" included in a "non-recommended matrix list" described later, and may be a precoding matrix indicated by a PMI fed back from a terminal (not shown). Alternatively, the precoding matrix used in the precoding process may be a "recommended precoding matrix" included in a "recommended matrix list" described later, and may be a precoding matrix indicated by a PMI fed back from a terminal (not shown).

[0018] <Control device configuration example> Fig. 2 is a block diagram showing an example of a control device in the first embodiment. The control device 30 shown in Fig. 2 is a device that controls the second communication device 20. For example, the control device 30 is mounted on or connected to the second communication device 20 for use.

[0019] 2, the control device 30 has a notification unit 31. The notification unit 31 notifies the first communication device 10 of a "non-recommended matrix list" or a "recommended matrix list" stored in a memory (not shown). The control device 30 may also notify the first communication device 10 of the "non-recommended matrix list" or the "recommended matrix list" via a management plane (M-plane) of an open run fronthaul. The YANG protocol of the management plane may be used for this notification. Furthermore, this notification may be performed before the second communication device 20 actually starts operating.

[0020] Here, the "non-recommended matrix list" is a list including information indicating "non-recommended preceding matrices" that are not recommended for use due to the "hardware configuration (hardware setting)" of the second communication device 20, among a plurality of preceding matrices included in a "codebook" that can be used for preceding processing. Also, the "recommended matrix list" is a list including information indicating "recommended preceding matrices" excluding the above-mentioned "non-recommended preceding matrices", among a plurality of preceding matrices included in a "codebook" that can be used for preceding processing.

[0021] The "hardware configuration (hardware setting)" of the second communication device 20 can be identified based on, for example, a parameter indicating the number of antenna ports, a parameter (N1, N2) indicating the antenna port array, and an oversampling parameter (O1, O2). These parameters will be described in detail later.

[0022] As described above, according to the first embodiment, the notification unit 31 in the control device 30 notifies the first communication device 10 of a "non-recommended matrix list" or a "recommended matrix list." The "non-recommended matrix list" is a list including information indicating "non-recommended precoding matrices" that are not recommended for use due to the "hardware configuration (hardware setting)" of the second communication device 20, among a plurality of precoding matrices included in a "codebook" that can be used for precoding processing. The "recommended matrix list" is a list including information indicating "recommended precoding matrices" excluding the above-mentioned "non-recommended precoding matrices," among a plurality of precoding matrices included in a "codebook" that can be used for precoding processing.

[0023] This configuration of the control device 30 makes it possible to directly or indirectly notify the first communication device 10 of a non-recommended precoding matrix that, when used, will cause a "reduction in the desired effect expected from multi-antenna communication" in consideration of the "hardware configuration" of the second communication device 20. This makes it possible to avoid the first communication device 10 from using a non-recommended precoding matrix. This makes it possible to suppress the "reduction in the desired effect expected from multi-antenna communication." In other words, it is possible to suppress the reduction in the desired effect expected from multi-antenna communication in a radio access network configuration in which a base station function group for performing multi-antenna communication is separately arranged in multiple communication devices.

[0024] <Second embodiment> The second embodiment relates to a more specific embodiment. The configuration of the communication system of the second embodiment is the same as that of the communication system 1 of the first embodiment, so refer to Fig. 1. That is, the communication system 1 of the second embodiment has a first communication device 40 and a second communication device 50 described later instead of the first communication device 10 and the second communication device 20.

[0025] <Configuration Example of First Communication Device> Fig. 3 is a block diagram showing an example of a first communication device in the second embodiment. The first communication device 40 shown in Fig. 3 is a communication device that executes a first signal processing including a precoding process and corresponding to a higher physical layer, similar to the first communication device 10 in the first embodiment. That is, here, O-RU and O-DU of Category A in Split Option 7-2X are assumed.

[0026] 3, the first communication device 40 has a baseband unit 41 and an interface unit 42. The baseband unit 41 has a precoding processing unit 41A. Although not described here, the baseband unit 41 may have an encoding unit, a scrambling unit, a modulation unit, and a layer mapping unit (not shown) at an input stage of the precoding processing unit 41A, and may have a resource element mapping unit at an output stage of the precoding processing unit 41A.

[0027] The precoding processing unit 41A multiplies an IQ sample sequence corresponding to one or more layers by a precoding matrix to form an IQ sample sequence after the precoding process. The formed IQ sample sequence after the precoding process is resource element mapped and transmitted to the second communication device 50 via the interface unit 42 as an IQ sample sequence of a frequency domain OFDM signal. That is, the IQ sample sequence of the frequency domain OFDM signal output from the interface unit 42 is transmitted to the second communication device 50 via the fronthaul. As described above, since O-RU and O-DU of category A in Split Option 7-2X are assumed here, the IQ sample sequence of the frequency domain OFDM signal is transmitted for each MIMO spatial stream (that is, for each antenna port).

[0028] Here, the precoding matrix used in the precoding processing unit 41A may be a precoding matrix excluding a "non-recommended precoding matrix" included in a "non-recommended matrix list" described later among a plurality of precoding matrices included in the "codebook". Alternatively, the precoding matrix used in the precoding processing unit 11A may be a "recommended precoding matrix" included in a "recommended matrix list" described later. Alternatively, the precoding matrix used in the precoding processing unit 11A may be a precoding matrix excluding a "non-recommended precoding matrix" included in a "non-recommended matrix list" described later, and may be a precoding matrix indicated by a PMI fed back from a terminal (not shown). Alternatively, the precoding matrix used in the precoding processing unit 11A may be a "recommended precoding matrix" included in a "recommended matrix list" described later, and may be a precoding matrix indicated by a PMI fed back from a terminal (not shown).

[0029] <Configuration example of second communication device> Fig. 4 is a block diagram showing an example of a second communication device in the second embodiment. Similar to the second communication device 20 in the first embodiment, the second communication device 50 shown in Fig. 4 is a communication device that performs baseband processing (second signal processing) including digital beamforming processing and corresponding to a lower physical layer, and wireless processing for converting a baseband signal into a wireless signal.

[0030] In FIG. 4, the second communication device 50 has an interface unit 51, a baseband unit 52, a radio frequency (RF) unit 53, an antenna array 54, and a control unit (control device) 60.

[0031] The interface unit 51 receives a signal transmitted from the first communication device 40, and outputs the received signal to the baseband unit 52 or the control unit 60. In addition, the interface unit 51 transmits a signal received from the baseband unit 52 or the control unit 60 to the first communication device 40.

[0032] The baseband unit 52 receives an IQ sample sequence of the frequency domain OFDM signal for each MIMO spatial stream (i.e., for each antenna port). Then, the baseband unit 52 executes the above-mentioned second signal processing on the IQ sample sequence for each antenna port. Note that, hereinafter, the IQ sample sequence for each antenna port may be referred to as a "first baseband signal."

[0033] For example, the baseband unit 52 has baseband processing units 55-1 to 55-4 each including a beamforming unit 55A. Hereinafter, when the baseband processing units 55-1 to 55-4 are not distinguished from one another, they may be simply referred to as baseband processing units 55. Each baseband processing unit 55 corresponds to an "endpoint" in the O-RAN fronthaul specifications. Although not described here, the baseband processing unit 55 may have an inverse fast Fourier transform (IFFT) unit (not shown) at the output stage of the beamforming unit 55A.

[0034] The four baseband processing units 55 correspond to different antenna ports. That is, the second communication device 50 shown in FIG. 4 has a hardware configuration having four antenna ports. In other words, the P csi-rs The value of P csi-rs =4.

[0035] The beamforming unit 55A of each baseband processing unit 55 performs digital beamforming processing on an IQ sample sequence of the frequency domain OFDM signal corresponding to one antenna port. Then, the IQ sample sequence of the frequency domain OFDM signal after the beamforming processing is converted into a time domain OFDM signal by IFFT processing and output to the RF unit 53.

[0036] Here, the baseband processing unit 55-1 forms an IQ sample sequence of N frequency domain OFDM signals corresponding to the antenna elements 57-1 to 57-N described later. The baseband processing unit 55-2 forms an IQ sample sequence of N frequency domain OFDM signals corresponding to the antenna elements 57-1 to 57-N described later. The IQ sample sequences of the two frequency domain OFDM signals formed by the baseband processing units 55-1 and 55-2 corresponding to the same antenna element are then added together. Then, an IFFT process is performed on the added IQ sample sequence to obtain a time domain OFDM signal.

[0037] Similarly, the baseband processing unit 55-3 forms an IQ sample sequence of N frequency domain OFDM signals corresponding to the antenna elements 57-N+1 to 57-2N described later. The baseband processing unit 55-4 forms an IQ sample sequence of N frequency domain OFDM signals corresponding to the antenna elements 57-N+1 to 57-2N described later. The IQ sample sequences of the two frequency domain OFDM signals formed by the baseband processing units 55-3 and 55-4 corresponding to the same antenna element are then added together. Then, an IFFT process is performed on the added IQ sample sequence to obtain a time domain OFDM signal.

[0038] The values ​​of DFT oversampling factors (parameters) O1 and O2 used here for forming beams are, for example, O1 = 4 and O2 = 1. That is, the second communication device 50 shown in Fig. 4 has a hardware configuration corresponding to O1 = 4 and O2 = 1. The parameter O1 represents the DFT oversampling factor (parameter) in the first dimension, and the parameter O2 represents the DFT oversampling factor (parameter) in the second dimension.

[0039] The radio frequency (RF) unit 53 receives a time-domain OFDM signal for each antenna element. Then, the radio frequency unit 53 performs radio processing (digital-to-analog conversion, up-conversion, etc.) on the time-domain OFDM signal for each antenna element. Note that, hereinafter, the time-domain OFDM signal for each antenna element may be referred to as a "second baseband signal."

[0040] The wireless unit 53 has wireless (RF) processing units 56-1 to 56-2 N. In the following, when the wireless (RF) processing units 56-1 to 56-2 N are not to be distinguished from one another, they may be simply referred to as wireless (RF) processing units 56.

[0041] The 2N radio processing units 56 correspond to different antenna elements. Each radio processing unit 56 performs radio processing (digital-to-analog conversion, up-conversion, etc.) on a time-domain OFDM signal (i.e., a second baseband signal) corresponding to one antenna element, and outputs the obtained radio signal to the antenna array 54.

[0042] The antenna array 54 has antenna elements 57-1 to 57-2N. Hereinafter, the antenna elements 57-1 to 57-2N may be simply referred to as antenna elements 57 when they are not to be distinguished from one another.

[0043] Here, the antenna elements 57-1 to 57-N correspond to vertical polarization (V), and the antenna subarrays 57-N+1 to 57-2N correspond to horizontal polarization (H). That is, each of the antenna elements 57-1 to 57-N is a V-polarized antenna element, and each of the antenna subarrays 57-N+1 to 57-2N is an H-polarized antenna element. The antenna elements 57-1 to 57-N correspond to a "first vertical antenna port" and a "second vertical antenna port". The antenna subarrays 57-N+1 to 57-2N correspond to a "first horizontal antenna port" and a "second horizontal antenna port". The values ​​of the parameters N1 and N2 indicating the antenna port array are, for example, N1=2 and N2=1. That is, the second communication device 50 shown in FIG. 4 has a hardware configuration corresponding to N1=2 and N2=1. The parameter N1 represents the number of vertical antenna ports (or horizontal antenna ports) in a first dimension, and the parameter N2 represents the number of vertical antenna ports (or horizontal antenna ports) in a second dimension.

[0044] At this time, the baseband processing units 55-1 and 55-2 are connected to the RF processing units 56-1 to 56-N by N connection lines (which can be called "first connection line group"), the number of which is the same as the total number of V-polarized antenna elements. The baseband processing units 55-3 and 55-4 are connected to the RF processing units 56-N+1 to 56-2N by N connection lines (which can be called "second connection line group"), the number of which is the same as the total number of H-polarized antenna elements. The RF processing units 56-1 to 56-N are connected to the antenna elements 57-1 to 57-N by N connection lines (which can be called "third connection line group"), the number of which is the same as the total number of H-polarized antenna elements. The RF processing units 56-N+1 to 56-2N are connected to the antenna elements 57-N+1 to 57-2N by N connection lines (which can be called "fourth connection line group"), the number of which is the same as the total number of H-polarized antenna elements.

[0045] The control unit (control device) 60 has a notification unit 61. The notification unit 61 is the same as the notification unit 31 of the first embodiment. Similarly, the first communication device 40 is notified of the "non-recommended matrix list" or the "recommended matrix list" held in a memory (not shown).

[0046] As described above, the "non-recommended matrix list" is a list including information indicating "non-recommended preceding matrices" that are not recommended for use due to the "hardware configuration (hardware setting)" of the second communication device 20, among a plurality of preceding matrices included in the "codebook" that can be used for preceding processing. In addition, the "recommended matrix list" is a list including information indicating "recommended preceding matrices" excluding the above-mentioned "non-recommended preceding matrices" among a plurality of preceding matrices included in the "codebook" that can be used for preceding processing.

[0047] The information indicating each precoding matrix included in the non-recommended matrix list and the recommended matrix list may include a "first parameter set" for identifying the "multi-antenna communication type" and a "second parameter set" for identifying the precoding matrix.

[0048] The above "first parameter set" is a parameter that indicates the number of antenna ports (P csi-rs ), parameters (N1, N2) indicating the antenna port array, oversampling parameters (O1, O2), and a parameter (rank number) indicating the number of layers available in the layer mapping process.

[0049] Here, a non-recommended precoding matrix whose use is not recommended due to the hardware configuration of the second communication device 50 is a precoding matrix that causes multiple second transmit baseband signals to be formed in the baseband unit 52, which are combined and cancel each other out within the second communication device 50.

[0050] For example, if the second communication device 50 is csi-rs= 4, N1 = 2, N2 = 1, O1 = 4, O2 = 1", the signals are inevitably combined in the antenna subarrays 57-1 and 57-2 corresponding to the vertical antenna ports, not in space, and the signals are inevitably combined in the antenna subarrays 57-3 and 57-4 corresponding to the horizontal polarization. For this reason, when the precoding processing unit 41A uses, for example, "a precoding matrix corresponding to i1,1 = 4, i1,2 = 0, i2 = 0, 1, 2, 3 of Rank 1", signals with a phase difference of 180 degrees in the antenna subarrays 57-1 and 57-2 cancel each other out, and as a result, a beam with low transmission power may be formed. In addition, since the data before the digital beamforming processing in the precoding processing unit 41A is already in a state of canceling each other out, there is a possibility that the combined data will cancel each other out greatly even if the digital beamforming processing in the precoding processing unit 41A is performed. As a result, a beam with low transmission power may be formed. Since the signals are combined in this way within the second communication device 50, even if signals are transmitted using transmit diversity of rank 1, the signals are not separated in space, and it may be difficult to obtain a diversity effect. In other words, the desired effect expected from multi-antenna communication may not be obtained or may be reduced.

[0051] For this reason, the notification unit 61 notifies the first communication device 40 of a "non-recommended matrix list" including information such as "Pcsi-rs=4, (N1,N2)=(2,1), (O1,O2)=(4,1):Rank1={i1,1=4, i1,2=0, i2=0,1,2,3}". Here, the "Pcsi-rs=4, (N1,N2)=(2,1), (O1,O2)=(4,1):Rank1" portion corresponds to the "first parameter set" for identifying the above-mentioned "multi-antenna communication type", and the "{i1,1=4, i1,2=0, i2=0,1,2,3}" portion corresponds to the "second parameter set" for identifying the above-mentioned precoding matrix. This configuration of the control unit (control device) 60 makes it possible to notify the first communication device 40 of a non-recommended precoding matrix whose use would result in a "reduction in the desired effect expected from multi-antenna communication" in consideration of the "hardware configuration" of the second communication device 50. This makes it possible to avoid the first communication device 40 from using a non-recommended precoding matrix. This makes it possible to suppress the "reduction in the desired effect expected from multi-antenna communication." In other words, it is possible to suppress the reduction in the desired effect expected from multi-antenna communication in a radio access network configuration in which a base station function group for performing multi-antenna communication is separately arranged in multiple communication devices.

[0052] The notification unit 61 may notify the first communication device 40 of the "non-recommended matrix list" (or the "recommended matrix list") before the second communication device 50 is actually operated. For example, in the O-RAN fronthaul specification, before the start of a service, the first communication device 40 acquires information such as an end point, an antenna array, and a polarization direction from the second communication device 50 using a management plane, and configures the antenna array for the second communication device 50 using the management plane based on the acquired information. Then, the control unit 60 of the second communication device 50 may determine what "multi-antenna communication type (PMI use case)" may exist based on the information set by the first communication device 40. Then, the notification unit 61 of the second communication device 50 may write the index of the non-recommended precoding matrix in the possible "multi-antenna communication type (PMI use case)" in the "non-recommended matrix list". In this manner, a "deprecated matrix list" including information such as the above "Pcsi-rs=4, (N1,N2)=(2,1), (O1,O2)=(4,1):Rank1={i1,1=4, i1,2=0, i2=0,1,2,3}" may be formed. The "deprecated matrix list" may be in a file format, and the file name may be predetermined between the first communication device 40 and the second communication device 50. The first communication device 40 may upload the "deprecated matrix list" in the file format to the second communication device 50 using a function defined as a "file management" function of the management plane in the O-RAN fronthaul specification.

[0053] <Other embodiments> FIG. 5 is a diagram showing an example of a hardware configuration of a control device. In FIG. 5, the control device 100 has a processor 101 and a memory 102. The processor 101 may be, for example, a microprocessor, a micro processing unit (MPU), or a central processing unit (CPU). The processor 101 may include a plurality of processors. The memory 102 is configured by a combination of a volatile memory and a non-volatile memory. The memory 102 may include a storage located away from the processor 101. In this case, the processor 101 may access the memory 102 via an I / O interface not shown.

[0054] The control devices 30 and 60 of the first and second embodiments may each have the hardware configuration shown in FIG. 5. The notification units 31 and 61 of the control devices 30 and 60 of the first and second embodiments may be realized by the processor 101 reading and executing a program stored in the memory 102. In addition, when the control devices 30 and 60 are included in the second communication devices 20 and 50, the baseband unit 52 of the second communication devices 20 and 50 may also be realized by the processor 101 reading and executing a program stored in the memory 102. The program can be stored using various types of non-transitory computer readable medium and supplied to the control devices 30 and 60. Examples of the non-transitory computer readable medium include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives) and magneto-optical recording media (e.g., magneto-optical disks). Further, examples of the non-transitory computer readable medium include CD-ROM (Read Only Memory), CD-R, and CD-R / W. Further, examples of the non-transitory computer readable medium include semiconductor memories. The semiconductor memory includes, for example, a mask ROM, a programmable ROM (PROM), an erasable PROM (EPROM), a flash ROM, and a random access memory (RAM). The program may be provided to the control device 30, 60 by various types of transitory computer readable media. Examples of the transitory computer readable media include an electric signal, an optical signal, and an electromagnetic wave. The transitory computer readable medium can provide the program to the control device 30, 60 via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

[0055] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention. [Explanation of symbols]

[0056] 1. Communication Systems 10 First communication device 11A Precoding processing unit 20 Second communication device 30 Control device 31 Notification Department 40 First communication device 41 Baseband section 41A Precoding processing unit 42 Interface section 50 Second communication device 51 Interface section 52 Baseband section 53 Radio Section 54 Antenna Array 55 Baseband processing section 55A Beamforming section 56 Radio Processing Unit 57 Antenna Element 60 Control unit (control device) 61 Notification Department

Claims

1. A control device that controls a second communication device out of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged, The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including a beamforming process and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The control device includes a notification unit configured to notify the first communication device of a non-recommended matrix list including information indicating a non-recommended precoding matrix that is not recommended for use due to a hardware configuration of the second communication device among a plurality of precoding matrices included in a codebook that can be used for the precoding process, or a recommended matrix list including information indicating a recommended precoding matrix excluding the non-recommended precoding matrix among the plurality of precoding matrices. Control device.

2. In the second signal processing, the beamforming processing is performed on a plurality of first transmit baseband signals formed by the first communication device and corresponding to a plurality of antenna ports, respectively; In the radio processing, radio processing is performed on a plurality of second transmit baseband signals formed in the second signal processing and corresponding to a plurality of antenna elements, respectively; A non-recommended precoding matrix whose use is not recommended due to a hardware configuration of the second communication device is a precoding matrix that causes the plurality of second transmit baseband signals that are combined and cancelled out in the second communication device to be formed in the second signal processing. The control device according to claim 1.

3. The information indicating each precoding matrix included in the non-recommended matrix list and the recommended matrix list includes a first parameter set for identifying a multi-antenna communication type and a second parameter set for identifying a precoding matrix. The control device according to claim 1 or 2.

4. The first signal processing further includes a layer mapping process and an antenna port mapping process; The first parameter set includes a parameter indicating the number of antenna ports, a parameter indicating an antenna port array, an oversampling parameter, and a parameter indicating the number of layers available in the layer mapping process. The control device according to claim 3.

5. The notification unit notifies the non-recommended matrix list or the recommended matrix list via a management plane (M-plane) of an open run fronthaul. A control device according to any one of claims 1 to 4.

6. A method executed by a control device that controls a second communication device out of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged, the method comprising: The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including a beamforming process and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The method includes notifying the first communication device of a non-recommended matrix list including information indicating a non-recommended precoding matrix that is not recommended for use due to a hardware configuration of the second communication device, among a plurality of precoding matrices included in a codebook usable for the precoding process, or a recommended matrix list including information indicating a recommended precoding matrix excluding the non-recommended precoding matrix among the plurality of precoding matrices. method.

7. A program for causing a control device that controls a second communication device out of a first communication device and a second communication device in which a base station function group for performing multi-antenna communication is separately arranged to execute a predetermined process, The first communication device performs a first signal processing including a precoding process and corresponding to a higher physical layer; the second communication device performs second signal processing including a beamforming process and corresponding to a lower physical layer, and radio processing for converting a baseband signal into a radio signal; The predetermined process includes notifying the first communication device of a non-recommended matrix list including information indicating a non-recommended precoding matrix that is not recommended for use due to a hardware configuration of the second communication device, among a plurality of precoding matrices included in a codebook usable for the precoding process, or a recommended matrix list including information indicating recommended precoding matrices excluding the non-recommended precoding matrices among the plurality of precoding matrices. program.

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