Network node, terminal device, control method, and program for improving accuracy of channel estimation

Abstract

A network node in a wireless communication network that provides a communication service to a terminal device having a plurality of antennas using a plurality of transmission / reception points, on the basis of the result of measurement of the reception quality of a sounding reference signal (SRS) transmitted from each of the plurality of antennas of the terminal device among the plurality of transmission / reception points. An SRS setting including a setting for whether or not the SRS should be transmitted by a plurality of resource sets corresponding to mutually different time resource sets is determined, and the SRS setting is notified to a terminal device using any one of a plurality of transmission / reception points.

Description

Technical Field

[0001] The present invention relates to a technology for improving the accuracy of channel estimation in wireless communications. Background Art

[0002] As a duplexing method in a cellular communication system, time division duplexing (TDD) is known. In TDD, different time slots in the same frequency channel are allocated for uplink (a link for sending signals from a terminal device to a network node (base station device)) and downlink (a link for sending signals from a network node to a terminal device) communications. In TDD, since the same frequency channel is used in the uplink and downlink, for example, a channel estimation value obtained on the network side based on a sounding reference signal (SRS) of the uplink can be used for downlink communications. Summary of the invention

[0003] Problems to be solved by the invention

[0004] In the downlink, signals can be sent from multiple transmission and reception points provided by one or more network nodes to a terminal device. To efficiently transmit such downlink signals, it is important to accurately estimate the channel between each of the multiple transmission and reception points and the multiple antennas of the terminal device.

[0005] Means used to solve problems

[0006] The present invention provides a technology for improving the accuracy of channel estimation between a transmission / reception point and a terminal device.

[0007] A network node based on one embodiment of the present invention is a network node in a wireless communication network that uses multiple transmitting and receiving points to provide communication services to a terminal device having multiple antennas, wherein the network node has: a determination unit that determines a setting of the SRS including a setting of whether the SRS should be sent through a set of multiple resources corresponding to a set of different time resources, based on a result of measuring the reception quality of a sounding reference signal (SRS) sent from each of the multiple antennas of the terminal device among the multiple transmitting and receiving points; and a notification unit that uses any one of the multiple transmitting and receiving points to notify the terminal device of the setting of the SRS.

[0008] A network node based on another embodiment of the present invention is a network node in a wireless communication network including a network node for communicating with a terminal device having multiple antennas using a part of a plurality of transmitting and receiving points, and other network nodes for communicating with the terminal device using another part of the plurality of transmitting and receiving points different from the part, wherein the network node has: an acquisition unit, which acquires a result of measuring the reception quality of a sounding reference signal (SRS) sent from each of the plurality of antennas of the terminal device in the part of the plurality of transmitting and receiving points; and a sending unit, which sends to the other network node information related to the result of measuring the reception quality of the SRS in the part of the plurality of transmitting and receiving points and the information on the setting of the SRS for enabling the other network node to decide whether the SRS should be sent through a set of multiple resources corresponding to sets of different time resources.

[0009] A terminal device based on one embodiment of the present invention is the terminal device in a wireless communication network that uses multiple transmitting and receiving points to provide communication services to the terminal device, wherein the terminal device has: multiple antennas; a receiving unit that receives, from a network node of the wireless communication network, a setting of a sounding reference signal (SRS) for measuring each of the multiple transmitting and receiving points, including a setting of whether the SRS should be sent through a set of multiple resources corresponding to a set of different time resources; and a sending unit that sends the SRS using the previous multiple antennas based on the SRS setting.

[0010] Effects of the Invention

[0011] According to the present invention, it is possible to estimate the channel between the transmission / reception point and the terminal device with high accuracy.

[0012] Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same reference numerals are used to designate the same or similar components. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention, and together with the description, serve to explain the principles of the present invention.

[0014] Figure 1 This is a diagram showing an example of the configuration of a wireless communication network.

[0015] Figure 2A It is a diagram showing an overview of the processing.

[0016] Figure 2B It is a diagram showing an overview of the processing.

[0017] Figure 3 This is a diagram showing an example of the hardware configuration of the device.

[0018] Figure 4 This is a diagram showing an example of the functional configuration of a network node.

[0019] Figure 5 This is a diagram showing an example of the functional configuration of a terminal device.

[0020] Figure 6 This is a diagram showing an example of a process flow executed in a wireless communication network. DETAILED DESCRIPTION

[0021] The following is a detailed description of the embodiments with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention involved in the technical solution. In addition, the combination of features described in the embodiments is not necessarily necessary for the invention. Two or more of the multiple features described in the embodiments may also be combined arbitrarily. In addition, the same or similar configurations are marked with the same figure numerals and repeated descriptions are omitted.

[0022] (Network Structure)

[0023] Figure 1 An example of the configuration of a wireless communication network involved in the present embodiment is shown. The wireless communication network is composed of a plurality of transmission and reception points (TRPs) 101 to 102 that are geographically dispersed, and a terminal device 111 that communicates with the network via the plurality of transmission and reception points. The transmission and reception points 101 to 102 are each composed of one or more antennas. In addition, the transmission and reception points 101 to 102 can be connected to a network node. That is, a network node can be configured to communicate with the terminal device 111 via a plurality of transmission and reception points that are geographically dispersed. It should be noted that this is an example, and the transmission and reception points 101 to 102 can also be connected to different network nodes, respectively. In this case, the first network node connected to the first transmission and reception point 101 and the second network node connected to the second transmission and reception point 102 cooperate to provide wireless communication services to the terminal device 111.

[0024] The quality of wireless communication service in such a wireless communication system depends on the accuracy of the channel estimation value between the antenna of the terminal device 111 and each antenna included in the multiple transmission and reception points 101 to 102. Here, in this embodiment, if time division duplex (TDD) is used, channel estimation can be performed by measuring the wireless quality of the sounding reference signal (SRS) transmitted from the terminal device 111 in each antenna of the multiple transmission and reception points. This is because in TDD, the same frequency channel is used in the downlink for transmitting signals from each transmission and reception point to the terminal device 111 and the uplink for transmitting signals from the terminal device 111 to each transmission and reception point.

[0025] For example, SRS is transmitted in a frequency resource in which a sequence known in the terminal device 111 and the transmission and reception point is configured in a predetermined interval in a set of time resources (a set of time resources composed of more than one resource element). At this time, SRS is transmitted using different sequences according to the antennas possessed by each terminal device 111, for example. That is, for example, when the terminal device 111 has four antennas, SRSs of different sequences are respectively transmitted in the four antennas. In this way, SRS is transmitted in the same time and frequency resources by multiplexing (frequency division multiplexing) in the power direction using different sequences. In the transmission and reception point, the SRS can be detected using a sequence corresponding to each antenna of the terminal device 111, and channel estimation between each antenna of the terminal device 111 and the transmission and reception point can be performed. It should be noted that when the transmission and reception point has multiple antennas, channel estimation between the terminal device 111 and each antenna is performed in each of the multiple antennas.

[0026] Here, if the total number of antennas in the terminal device 111 increases, the power of each sequence becomes insufficient because a plurality of sequences are multiplexed in the power direction. Figure 1 At a transmission / reception point located far from the terminal device 111, such as the transmission / reception point 102, the SRS cannot be received with sufficient power, and the channel estimation accuracy becomes insufficient.

[0027] In this embodiment, in view of the above situation, for example, when the power of SRS is insufficient, SRS is sent through a set of multiple resources corresponding to different time resources. Figure 2A As shown, it is assumed that the terminal device 111 is transmitting SRS in a resource set consisting of two resource elements in the time direction and a predetermined number of resource elements in the frequency direction. In this state, for example, when it is determined that the power of SRS is insufficient at the transmission and reception point 102, as shown in FIG. Figure 2B As shown, a set of other resources that are not transmitting SRS in the time direction is used as resources for transmitting supplementary SRS. Then, the terminal device 111, for example, transmits SRS corresponding to a part of antennas in the resources for transmitting supplementary SRS, and stops transmitting SRS corresponding to the part of antennas in the resources for transmitting SRS that were originally used. Thus, the number of sequences multiplexed in the simultaneously transmitted SRS can be reduced, thereby increasing the transmission power of each sequence of SRS. By increasing the transmission power of each sequence of SRS, the power of SRS received at the transmission and reception point can be increased, and as a result, channel estimation can be performed with high accuracy.

[0028] In order to perform such processing, a network node that is connected to a transmission and reception point and controls communication via the transmission and reception point determines the setting of the SRS based on the measurement results of the reception quality (e.g., reception power, signal-to-noise ratio, etc.) of the SRS in multiple transmission and reception points. Here, the setting of the SRS includes the setting of whether to disperse and send the SRS through multiple resource sets corresponding to different sets of time resources. Then, the network node notifies the terminal device 111 of the determined SRS setting. It should be noted that it can be assumed that the network node is connected to all multiple transmission and reception points and controls the communication at these transmission and reception points. In this case, the network node observes the SRS according to the setting after notifying the terminal device 111 of the SRS setting.

[0029] On the other hand, in the case where the network node is connected to only a part of the multiple transmission and reception points and other network nodes are connected to another part of the transmission and reception points, the network node notifies not only the terminal device 111 of the SRS settings but also the other network nodes of the SRS settings. As a result, the other network nodes can observe the SRS from the terminal device 111 based on the notified SRS settings in the above-mentioned other part of the transmission and reception points. In addition, the network node can receive information related to the measurement results of the SRS obtained in the other part of the transmission and reception points connected to the other network nodes from the other network nodes when determining the SRS settings. Then, the network node determines the SRS settings based on the measurement results of the SRS reception quality in a part of the multiple transmission and reception points connected to the own device and the information related to the measurement results of the SRS received from the other network nodes.

[0030] It should be noted that the information related to the measurement result of the SRS can be, for example, information indicating changes in the settings of the SRS based on the measurement result of the reception quality of the SRS in the transmission and reception point connected to other network nodes. For example, in a case where the reception quality of the SRS in the transmission and reception point connected to other network nodes is below a predetermined level, information indicating changes in the settings of the SRS for transmitting the SRS through a set of multiple resources corresponding to different times can be notified from other network nodes to network nodes. That is, when other network nodes obtain the measurement result of the reception quality of the SRS in the corresponding transmission and reception point, and, for example, the value of the measurement result is below a predetermined level, Figure 2BAs shown, it is possible to determine that resources for sending a supplementary SRS that are different from the resources and time used for sending the SRS currently in use should be used. Then, the other network nodes can generate change indication information indicating the decision and send it to the network node. In addition, for example, in a case where the reception quality of the SRS significantly exceeds a predetermined level at a sending and receiving point connected to other network nodes and the SRS is being sent through a set of multiple resources corresponding to different times, change indication information for setting the SRS to be sent through a set of fewer resources than the SRS currently being sent through the set of multiple resources can be notified from the other network nodes to the network node. When the network node receives the change indication information for the setting of the SRS, it can determine the setting of the SRS based on the change indication information. For example, when the network node is sending the SRS through a set of multiple resources, the network node can determine the setting of the SRS based on the change indication information. Figure 2A In the case of sending SRS with such resource configuration, if the change indication information indicating that SRS should be sent is received through a set of multiple resources corresponding to different times, it is possible to Figure 2B The resource configuration changes the SRS setting. Figure 2B In the case of sending SRS using such resource configuration, if a change indication information indicating that SRS should be sent using a set of resources is received, it is possible to send SRS using Figure 2A Such resource allocation changes the setting of SRS in the way of sending SRS.

[0031] It should be noted that the change indication information may also be, for example, information indicating that the setting should be changed in a manner that increases the power of the SRS by a predetermined level. For example, suppose that, based on the change indication information, the network node is notified from other network nodes that the received power of the SRS should be improved by 3dB. In this case, the network node determines the setting of the SRS by, for example, halving the number of SRS sequences sent at the same time and sending SRS sequences of a reduced amount at other times. By halving the number of SRS sequences sent at one time, the transmission power according to the sequence can be doubled. As a result, the received power of the SRS passing through the transmission and reception points corresponding to other network nodes can be improved by 3dB.

[0032] In addition, the information related to the measurement result of the SRS may be information indicating the measurement result of the reception quality of the SRS in the transmission and reception point connected to other network nodes. If the network node receives this information, it determines the setting of the SRS based on at least one of the first measurement result related to the reception quality of the SRS in the transmission and reception point connected to the device and the second measurement result related to the reception quality of the SRS in the transmission and reception point connected to other network nodes indicated by the received information. For example, in the case where the second measurement result is lower than a predetermined value, such as Figure 2B As shown, the network node can determine the setting of the SRS by reducing the number of sequences of the SRS sent at one time. In addition, when the difference between the first measurement result and the second measurement result (the absolute value of the difference) exceeds a predetermined value, the network node can also determine the setting of the SRS by reducing the number of sequences of the SRS sent at one time. The predetermined value can be, for example, 3dB, 6dB, 10dB, etc.

[0033] The terminal device 111 transmits the SRS of the sequence related to the wireless resource through the designated wireless resource according to the SRS setting determined as above. Here, it is assumed that the terminal device 111 has four antennas in total. In this case, for example, Figure 2A In a set of such resources, when a setting of SRS is used to send a total of four sequences corresponding to each antenna, the terminal device 111 generates SRS corresponding to each antenna using four sequences according to the setting, and sends these SRSs through the corresponding antennas using common frequency and time resources. Figure 2B As shown in the figure, the SRS setting is such that the SRS corresponding to the two antennas are respectively transmitted using a set of multiple resources at different times. In this case, the terminal device 111 transmits the SRS generated using the two sequences corresponding to the two antennas from the corresponding antennas in the set of resources at an earlier time according to the setting. In addition, the terminal device 111 transmits the SRS generated using the two sequences corresponding to the remaining two antennas from the corresponding antennas in the set of resources at a later time.

[0034] As described above, by expanding the setting of resources for sending SRS and dispersing them in a manner such that the sending time of SRS based on a part of the sequence is different from the sending time of SRS based on another part of the sequence, the reception quality of SRS in the sending and receiving points of the network can be improved and the channel estimation accuracy can be improved.

[0035] It should be noted that, in the above-mentioned configuration example, an example in which the network node connected to the transmitting and receiving point determines the setting of the SRS is described, but the same processing as the above-mentioned processing can be performed through any configuration. For example, each transmitting and receiving point can also have the function of being the above-mentioned network node. In this case, each transmitting and receiving point can also cooperate with other transmitting and receiving points to determine the setting of the SRS to be used in the terminal device as above. In addition, the setting of the SRS to be used in the terminal device can also be determined in a node higher than the network node. In this case, the measurement results of the reception quality of the SRS in each antenna of each transmitting and receiving point can be collected at the upper node, and the setting of the SRS to be used in the terminal device can be determined based on the information collected at the upper node. In addition, in the above-mentioned example, an example of a process of dividing four antennas into groups of two each so that the corresponding SRS transmission times are different is described, but it is not limited to this. For example, four antennas can be grouped into one antenna and three antennas, or divided into three or more groups such as one antenna, one antenna, and two antennas, and the SRS corresponding to the antennas belonging to each group is sent at different times to determine the setting of the SRS. In addition, in the above-mentioned embodiment, the case of using multiple transmission and reception points is described, but the above-mentioned processing can also be performed for the purpose of high-precision channel estimation in one transmission and reception point. In this way, the above-mentioned processing can be performed in a manner in which various changes are applied. In addition, the above-mentioned processing can also be used in any combination.

[0036] (Device Configuration)

[0037] use Figure 3 An example of the hardware configuration of a network node (e.g., a base station device) and a terminal device is described. In one example, the network node and the terminal device include a processor 301, a ROM 302, a RAM 303, a storage device 304, and a communication circuit 305. The processor 301 is a computer including one or more processing circuits such as a general-purpose CPU (central processing unit) and an ASIC (application-specific integrated circuit), and performs the processing of the entire device and the above-mentioned processing by reading and executing programs stored in the ROM 302 and the storage device 304. ROM 302 is a read-only memory that stores information such as programs and various parameters related to the processing performed by the network node and the terminal device. RAM 303 functions as a workspace when the processor 301 executes the program, and is also a random access memory that stores temporary information. The storage device 304 is, for example, composed of a removable external storage device. The communication circuit 305 is, for example, composed of circuits for wireless communications of 5G and subsequent specifications. It should be noted that in Figure 3In the figure, a communication circuit 305 is illustrated, but the network node and the terminal device can have multiple communication circuits. For example, the network node and the terminal device can have an antenna common to the wireless communication circuit for 5G and subsequent specifications. It should be noted that the network node and the terminal device may also have an antenna for 5G and an antenna for subsequent specifications. In addition, the terminal device may also have a communication circuit for other wireless communication networks such as wireless LAN. It should be noted that the network node and the terminal device may have an additional communication circuit 305 for each of the multiple frequency bands that can be used, and may also have a common communication circuit 305 for at least a part of these frequency bands. In addition, the network node can further have a wired communication circuit used when communicating with other network nodes and nodes of the core network. It should be noted that the network node may not have a wireless communication circuit, but may have a wired communication circuit with a sending and receiving point. That is, the sending and receiving point is given a wireless communication function, and the network node may also be configured in a manner that is unrelated to the processing of wireless communication.

[0038] Figure 4 401, an SRS setting determination unit 402, a setting notification unit 403, and an information exchange unit 404 are provided as functions of the network node. Figure 4 In the figure, only the functions that are particularly relevant to this embodiment are shown, and the various other functions that the network node can have are omitted. For example, the network node naturally has other functions that the network node of 5G or its subsequent specifications generally has. In addition, Figure 4 The functional blocks are schematically shown, and each functional block can be implemented in an integrated manner or further refined. Figure 4 Each function of the MCU 301 can be realized by, for example, executing a program stored in the ROM 302 or the storage device 304, or can be realized by, for example, executing predetermined software by a processor in the communication circuit 305. It should be noted that the details of the processing performed by each functional unit are not described here, and only the general functions are summarized.

[0039] The reception quality acquisition unit 401 obtains information on the measurement result of the reception quality when the SRS sent from the terminal device is measured from the transmission and reception point in the transmission and reception point connected to the network node itself. It should be noted that the transmission and reception point can also forward the received wireless signal to the network node by, for example, only performing frequency conversion. In this case, the reception quality acquisition unit 401 can also measure the SRS based on the forwarded wireless signal and obtain the measurement result of the reception quality of the SRS. It should be noted that the reception quality of the SRS can be obtained, for example, as the size of the channel estimation value (the absolute value of the channel estimation value) or the square value of the channel estimation value in each transmission and reception point. In addition, the reception quality of the SRS can also be expressed by other metrics such as the signal-to-noise ratio. The network node can provide information indicating the measurement result of the reception quality of the SRS to other network nodes through the information exchange unit 404 as needed.

[0040] The SRS setting determination unit 402 determines the setting of the SRS that the terminal device should use based on the reception quality of the SRS acquired by the reception quality acquisition unit 401. For example, when the reception quality of the SRS acquired by the reception quality acquisition unit 401 is lower than a predetermined level, it can be decided to set it in a manner that reduces the number of SRS sequences that should be sent at one time and increases the transmission power of each SRS sequence. In addition, when the reception quality of the SRS acquired by the reception quality acquisition unit 401 is much higher than a predetermined level, the SRS setting determination unit 402 can decide to set it in a manner that increases the number of SRS sequences that should be sent at one time and reduces the wireless resources to which the SRS is transmitted. It should be noted that the SRS setting determination unit 402 specifies the sequence that should be used for the generation of the SRS for each antenna of the terminal device 111. It should be noted that the sequences corresponding to the SRSs transmitted at the same time need to be different from each other, but the sequences corresponding to the SRSs transmitted at different times can also be the same. In addition, the SRS setting decision unit 402 may also obtain the second measurement result of the reception quality of the SRS in the transmission and reception point corresponding to other network nodes through the information exchange unit 404, and determine the setting of the SRS based on the first measurement result of the reception quality obtained by the reception quality acquisition unit 401 and the received second measurement result. In one example, when the difference between the first measurement result and the second measurement result exceeds a predetermined value, the SRS setting decision unit 402 can determine the setting of the SRS such that the number of SRS sequences to be transmitted at one time is reduced in order to improve the reception quality of the SRS with low reception quality. In addition, the SRS setting decision unit 402 can determine to reduce, for example, the number of SRS sequences to be transmitted at one time based on the measurement result of the reception quality obtained by the reception quality acquisition unit 401, and generate change indication information indicating the content of the decision. In addition, the SRS setting decision unit 402 may also generate change indication information including information indicating to what extent the reception quality should be improved based on the measurement result of the reception quality obtained by the reception quality acquisition unit 401. Then, the change indication information can be sent to other network nodes through the information exchange unit 404.

[0041] The setting notification unit 403 notifies the terminal device of the SRS setting determined in the SRS setting determination unit 402. The setting notification unit 403 can be sent to the terminal device according to a radio resource control (RRC) message, for example. In addition, for example, the setting notification unit 403 can also pre-send multiple SRS settings to the terminal device according to the RRC message, and then send information specifying which of the multiple SRS settings to use according to the downlink control information (DCI). Through such a configuration, the network node can enable the terminal device to easily and quickly change the SRS setting according to the communication status. In addition, the setting notification unit 403 can notify other network nodes of the finally determined SRS setting, for example, via the information exchange unit 404.

[0042] The information exchange unit 404 exchanges information with other network nodes as described above. It should be noted that the information exchange unit 404 collects information from the network node connected to the transmission and reception point of the service cell providing the terminal device. Then, the network node that has collected the information finally determines the setting of the SRS and notifies the terminal device and other network nodes of the determined SRS setting. It should be noted that the information exchange unit 404 can exchange information with other network nodes via the Xn interface and the NG interface.

[0043] Figure 5 501 and 502. Figure 5 In the figure, only the functions that are particularly relevant to this embodiment are shown, and other various functions that the terminal device may have are omitted. For example, the terminal device naturally has other functions that terminal devices of 5G and subsequent specifications generally have. In addition, Figure 5 The functional blocks are schematically shown, and each functional block can be implemented in an integrated manner or further refined. Figure 5 Each function of the MCU 301 can be realized by, for example, executing a program stored in the ROM 302 or the storage device 304, or by, for example, executing predetermined software by a processor in the communication circuit 305. It should be noted that the details of the processing performed by each functional unit are not described here, and only the general functions are summarized.

[0044] The setting receiving unit 501 receives the setting of SRS from the network node providing the serving cell. The setting of SRS can be received, for example, through a radio resource control (RRC) message. In addition, for example, the setting receiving unit 501 can also receive multiple SRS settings in advance according to the RRC message and receive information specifying whether to use any of the multiple SRS settings according to downlink control information (DCI). The SRS transmitting unit 502 transmits the SRS using the setting received by the setting receiving unit 501.

[0045] (Processing flow)

[0046] Next, use Figure 6 An example of a process flow executed in a wireless communication network is described. It should be noted that since the details of the process steps described here are as described above, only an outline of the process flow is described here. It should be noted that here, a case where two network nodes (network node A and network node B) correspond to different transmission and reception points is described. In addition, here, it is assumed that network node A provides a service cell.

[0047] First, SRS is set between network node A and the terminal device in the same manner as in the previous process. First, network node A requests the terminal device to send capability information (UE capability) (S601). In response to the request, the terminal device sends UE capability to network node A (S602). The UE capability here includes, for example, information on the number of antennas that the terminal device 111 has. In one example, the terminal device 111 notifies network node A that it has four antennas. Network node A determines the initial SRS setting based on the UE capability and notifies the terminal device (S603). The SRS setting here is, for example, Figure 2A As shown, it is assumed that the SRS setting is performed such that the corresponding SRS is transmitted from each of the four antennas of the terminal device 111 at the same time. In addition, the SRS setting can be notified from the network node A to the terminal device using RRC signaling, for example. If the terminal device receives the SRS setting, it notifies the network node A of a response message indicating successful reception (S604). Thus, the initial SRS setting is completed.

[0048] The terminal device 111 generates an SRS corresponding to each antenna, and according to the settings notified in S603, uses the same frequency and time resource set to send the SRS from the corresponding antenna (S605). The network node A and the network node B measure the SRS sent from each antenna of the terminal device 111 in each antenna of the respectively connected transmission and reception point (S606). The network node A and the network node B perform channel estimation based on the SRS and measure the reception quality of the SRS. It should be noted that the measurement result of the reception quality of the SRS can also be obtained using the result of channel estimation such as the absolute value of the channel estimation value.

[0049] Here, it is assumed that the measurement result of the reception quality of the SRS in the network node B is insufficient for high-precision channel estimation. In this case, in one example, the network node B notifies the network node A that is providing the serving cell of the change indication information (S607) that the setting should be changed. This notification can be performed, for example, using the Xn interface or the NG interface. It should be noted that the network node B can also be judged in the network node A whether the measurement result of the reception quality of the SRS should be notified to the network node A and the setting of the SRS should be changed. In addition, the network node B may not notify the network node A of the content that should be changed, but notify the network node A of, for example, a request for a 3dB improvement in the reception quality. The network node A decides whether the setting of the SRS should be changed based on the reception quality of the SRS obtained in the present device and the information notified from the network node B. Here, the network node A can decide to reduce the number of SRS sequences sent at a time and decide to use Figure 2B Such settings (S608). Then, network node A notifies the terminal device of the determined SRS settings (S609). The notification of the SRS settings here can be performed using an RRC message, or using other forms of messages such as DCI. It should be noted that network node A also notifies network node B of the determined SRS settings (S610). This notification can be performed, for example, using an Xn interface or an NG interface.

[0050] Afterwards, the terminal device uses the notified SRS setting to send SRS corresponding to a part of the antennas (S611), and the network node A and the network node B use the SRS to perform channel estimation and reception quality measurement (S612). In addition, the terminal device uses the notified SRS setting to send SRS corresponding to the remaining part of the antennas that did not send SRS in S611 (S613), and the network node A and the network node B use the SRS to perform channel estimation and reception quality measurement (S614). By using such an SRS setting, the reception quality of the SRS in the transmission and reception point is improved because the transmission power of each sequence is increased. As a result, the accuracy of the channel estimation between each antenna of the terminal device and the antenna of the transmission and reception point can be improved.

[0051] As described above, in this embodiment, the setting of resources for sending SRS is expanded and dispersed in a manner that the sending time of SRS based on a part of the sequence is different from the sending time of SRS based on another part of the sequence. As a result, the reception quality of SRS in the sending and receiving points of the network can be improved and the channel estimation accuracy can be improved. Therefore, it is possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Maintaining resilient infrastructure, promoting sustainable industrialization, and achieving the expansion of innovation."

[0052] The present invention is not limited to the above-described embodiments, and various modifications and changes can be made within the scope of the gist of the invention.

[0053] This application claims priority based on Japanese patent application No. 2022-127710 filed on August 10, 2022, the entire contents of which are incorporated herein by reference.

Claims

1. A network node, which is a network node in a wireless communication network that uses multiple transmission and reception points to provide communication services to terminal devices with multiple antennas, wherein: The network node has: a determination unit that determines, based on a result of a measurement of reception quality of a sounding reference signal (SRS) transmitted from each of the plurality of antennas of the terminal device at the plurality of transmission and reception points, a setting of the SRS including a setting of whether the SRS should be transmitted through a set of a plurality of resources corresponding to a set of different time resources; as well as A notification unit that uses any one of the plurality of transmission and reception points to notify the terminal device of the setting of the SRS.

2. The network node according to claim 1, wherein: The network node communicates with the terminal device using a portion of the plurality of transmission and reception points, Another network node different from the network node communicates with the terminal device using another part of the plurality of transmission and reception points different from the part, The network node also has: an acquisition unit configured to acquire a result of measuring the reception quality of the SRS at the part of the plurality of transmission and reception points; as well as a receiving unit that receives information related to a result of measuring the reception quality of the SRS in the other part of the plurality of transmission and reception points from the other network node, The determination unit determines the setting of the SRS based on at least one of a result of measuring the reception quality of the SRS at the part of the plurality of transmission and reception points and the information.

3. The network node according to claim 2, wherein: The information is information indicating a change in the setting of the SRS from the other network node based on a result of measuring the reception quality of the SRS in the other part of the plurality of transmission and reception points, The determination unit determines the setting of the SRS according to the change instruction information when receiving the information.

4. The network node according to claim 3, wherein: The determination unit receives the change indication information during a period in which the SRS for measuring the reception quality of the SRS in the part of the multiple transmission and reception points and the SRS for measuring the reception quality of the SRS in the other part of the multiple transmission and reception points are transmitted in the same time resource, and determines the setting of the SRS in such a manner that the SRS corresponding to the part of the multiple antennas of the terminal device is transmitted in a time resource different from the SRS in the other part of the multiple antennas.

5. The network node according to claim 2, wherein: The information is information indicating a result of measuring the reception quality of the SRS in the other part of the plurality of transmission and reception points, The determination unit determines the setting of the SRS based on a first result of measuring the reception quality of the SRS in the part of the multiple transmission and reception points and a second result of measuring the reception quality of the SRS in the other part of the multiple transmission and reception points.

6. The network node according to claim 5, wherein: When the difference between the first result and the second result exceeds a predetermined value, the determination unit determines the setting of the SRS in such a manner that the SRS corresponding to a part of the multiple antennas of the terminal device is transmitted in a time resource different from the SRS in another part of the multiple antennas.

7. The network node according to claim 1, wherein: The network node communicates with the terminal device using a portion of the plurality of transmission and reception points, another network node different from the network node communicates with the terminal device using another part of the plurality of transmission and reception points different from the part, The network node also has: an acquisition unit configured to acquire a result of measuring the reception quality of the SRS at the part of the plurality of transmission and reception points; as well as a transmitting unit configured to transmit information related to a result of measuring the reception quality of the SRS at the part of the plurality of transmission and reception points to the other network node, The decision unit determines, based on the result of the measurement of the reception quality of the SRS in the part of the multiple transmission and reception points, that the SRS corresponding to the part of the multiple antennas of the terminal device should be transmitted in a time resource different from the SRS in another part of the multiple antennas, The transmitting unit transmits, as the information, change instruction information indicating a result based on the determination by the determining unit to the other network node.

8. A network node, the network node being in a wireless communication network including a network node that communicates with a terminal device having multiple antennas using a part of a plurality of transmission and reception points, and another network node that communicates with the terminal device using another part of the plurality of transmission and reception points different from the part, wherein: The network node has: an acquisition unit that acquires a result of measuring reception quality of a sounding reference signal (SRS) transmitted from each of the plurality of antennas of the terminal device in the portion of the plurality of transmission and reception points; as well as A sending unit that sends information related to the result of measuring the reception quality of the SRS from the part of the multiple sending and receiving points to the other network node and is used to enable the other network node to determine the setting of the SRS, including the setting of whether the SRS should be sent through a set of multiple resources corresponding to sets of different time resources.

9. A terminal device, which is the terminal device in a wireless communication network that uses a plurality of transmission and reception points to provide communication services to the terminal device, wherein: The terminal device comprises: Multiple antennas; a receiving unit receiving, from a network node of the wireless communication network, a setting of a sounding reference signal (SRS) including a setting of whether the SRS for measurement at each of the plurality of transmission and reception points should be transmitted via a set of a plurality of resources corresponding to a set of different time resources; as well as A transmitting unit transmits the SRS using a plurality of antennas in the previous stage based on the setting of the SRS.

10. A control method, which is a control method performed by a network node in a wireless communication network that uses multiple transmission and reception points to provide communication services to terminal devices with multiple antennas, wherein: The control method includes the following contents: Based on the result of the measurement of the reception quality of the sounding reference signal (SRS) transmitted from each of the multiple antennas of the terminal device in the multiple transmission and reception points, the setting of the SRS including the setting of whether the SRS should be transmitted through a set of multiple resources corresponding to a set of different time resources is determined, The setting of the SRS is notified to the terminal device using any one of the plurality of transmission and reception points.

11. A control method, which is a control method performed by a network node in a wireless communication network including a network node that uses a part of a plurality of transmission and reception points to communicate with a terminal device having a plurality of antennas, and other network nodes that use another part of the plurality of transmission and reception points different from the part to communicate with the terminal device, wherein: The control method includes the following contents: obtaining a result of measuring reception quality of a sounding reference signal (SRS) transmitted from each of the plurality of antennas of the terminal device in the portion of the plurality of transmission and reception points, Information related to the result of measuring the reception quality of the SRS among the part of the multiple sending and receiving points is sent to the other network node, and the information is used to enable the other network node to determine the settings of the SRS, including the settings of whether the SRS should be sent through a set of multiple resources corresponding to sets of different time resources.

12. A control method, which is a control method performed by a terminal device in a wireless communication network that provides communication services to a terminal device having multiple antennas using multiple transmission and reception points, wherein: The control method includes the following contents: receiving, from a network node of the wireless communication network, a setting of a sounding reference signal (SRS) including a setting of whether a measurement at each of the plurality of transmission / reception points should be transmitted via a set of a plurality of resources corresponding to sets of different time resources, Based on the setting of the SRS, the SRS is sent using multiple antennas in the early stage.

13. A program for causing a computer included in a network node in a wireless communication network that provides communication services to a terminal device having multiple antennas using multiple transmission and reception points to execute the following control: Based on the result of the measurement of the reception quality of the sounding reference signal (SRS) transmitted from each of the multiple antennas of the terminal device in the multiple transmission and reception points, the setting of the SRS including the setting of whether the SRS should be transmitted through a set of multiple resources corresponding to a set of different time resources is determined, The setting of the SRS is notified to the terminal device using any one of the plurality of transmission and reception points.

14. A program for causing a computer included in a wireless communication network including a network node that communicates with a terminal device having multiple antennas using a part of a plurality of transmission and reception points and another network node that communicates with the terminal device using another part of the plurality of transmission and reception points different from the part to execute the following control: obtaining a result of measuring reception quality of a sounding reference signal (SRS) transmitted from each of the plurality of antennas of the terminal device in the portion of the plurality of transmission and reception points, Information related to the result of measuring the reception quality of the SRS among the part of the multiple sending and receiving points is sent to the other network node, and the information is used to enable the other network node to determine the settings of the SRS, including the settings of whether the SRS should be sent through a set of multiple resources corresponding to sets of different time resources.

15. A program for causing a computer included in a terminal device in a wireless communication network that provides communication services to a terminal device having multiple antennas using multiple transmission and reception points to execute the following control: receiving, from a network node of the wireless communication network, a setting of a sounding reference signal (SRS) including a setting of whether a measurement at each of the plurality of transmission / reception points should be transmitted via a set of a plurality of resources corresponding to sets of different time resources, The SRS is transmitted using a plurality of antennas in the previous stage based on the setting of the SRS.

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