Terminal device, network device, control method, and computer-readable storage medium

Abstract

A terminal device that can connect to one or more base station devices that respectively form one or more beams monitors the connection target beam to be used by the terminal device when establishing a connection with any of the one or more base station devices in a non-connected state in which the terminal device is not connected to any of the one or more base station devices, and reports information related to the connection target beam to the base station device that forms the connection target beam based on at least a change in the connection target beam. Based on the information related to the connection target beam, control is performed as to which beam any of the one or more base station devices uses to perform paging for the terminal device.

Description

[0001] This application is a divisional application of Chinese patent application 201780054881.7, entitled “Terminal device, network device, control method and computer-readable storage medium”, filed on June 21, 2017. Technical Field

[0002] The present invention relates to a terminal device, a network device, a control method and a computer-readable storage medium, and in particular to a paging technology in wireless communication. Background Art

[0003] In the 3rd Generation Partnership Project, new wireless access technologies for the fifth generation (hereinafter referred to as "5G") are being studied (refer to non-patent document 1). In the 5G system, it is assumed that a base station device, also referred to as NR gNB, is configured to include a plurality of devices referred to as Central Unit (CU) and Distributed Unit (DU). In addition, DU is also referred to as Transmission Receiver Point (TRP). Here, it is assumed that the DU processes at least a layer including a physical (PHY) layer at a position at least lower than the radio resource control (RRC) layer, and the CU processes a layer including an RRC layer at a position higher than the layer controlled by the DU. In addition, it is assumed that multiple DUs are connected to one CU. Furthermore, one DU forms one or more beams, for example, by beamforming, and uses at least any one of the beams to establish a connection with a terminal device. That is, the base station device is configured to include at least one CU and a plurality of DUs connected to the CU, and by forming one or more beams by each DU, a plurality of beams are formed, and a connection with a terminal device is established using at least any one of the plurality of beams.

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-patent document 1: 3GPP contribution, RP-160671, March 2016

[0007] Non-patent document 2: 3GPP, TS36.331 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the existing LTE (Long Term Evolution) system, when calling a terminal device, a paging message is sent simultaneously from the core network to all base station devices assigned the same Tracking Area Code (TAC). Moreover, the base station device that receives the paging message sends the paging message through a wireless signal in the cell provided by itself, and calls the terminal device staying in any cell. If such a paging method is directly applied to the 5G system, the paging message is sent through multiple beams, which may cause waste of wireless resources such as space resources and interference with other signals caused by paging messages.

[0010] Methods used to solve problems

[0011] The present invention provides a technology for performing calls on terminal devices with higher wireless resource utilization efficiency and low interference.

[0012] A terminal device involved in one embodiment of the present invention is a terminal device capable of connecting to one or more base station devices that respectively form more than one beam, wherein the terminal device has: a monitoring unit that monitors a connection object beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices in a non-connected state in which the terminal device is not connected to any of the one or more base station devices; and a reporting unit that reports information related to the connection object beam to the base station device that forms the connection object beam based on at least a situation in which the connection object beam has changed, and controls which beam any of the one or more base station devices uses to perform paging for the terminal device based on the information related to the connection object beam.

[0013] A network device involved in one embodiment of the present invention is a network device in a network including one or more base station devices that respectively form one or more beams, wherein the network device has: a receiving unit that receives a report from a terminal device that can be connected to the one or more base station devices, the report being a report related to a connection object beam to be used when the terminal device establishes a connection with any one of the one or more base station devices in a non-connected state; and a control unit that controls the terminal device to be paged using a beam that includes a part of the connection object beam among multiple beams formed by the one or more base station devices.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to perform a call to a terminal device with high radio resource utilization efficiency and low interference.

[0016] Other features and advantages of the present invention will become clear from the following description with reference to the accompanying drawings. In addition, in the accompanying drawings, the same reference numerals are used for the same or similar structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which 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.

[0018] Figure 1 It is a diagram showing a configuration example of a wireless communication system.

[0019] Figure 2 It is a diagram showing an example of the hardware configuration of a terminal device and a network device.

[0020] Figure 3 This is a diagram showing an example of the functional configuration of a terminal device.

[0021] Figure 4 This is a diagram showing an example of a functional configuration of a network device.

[0022] Figure 5 This is a diagram showing a first example of the flow of call processing performed in the wireless communication system.

[0023] Figure 6 This is a diagram showing a second example of the flow of call processing executed in the wireless communication system.

[0024] Figure 7 This is a diagram showing a third example of the flow of call processing performed in the wireless communication system. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0026] (Configuration of wireless communication system)

[0027] Figure 1 An example of the configuration of a wireless communication system involved in the present embodiment is shown. The wireless communication system involved in the present embodiment is, for example, a fifth generation (5G) mobile wireless communication system, which is configured to include a base station device (NR gNB) and a terminal device. A wireless connection is established between the base station device and the terminal device, and a wireless signal is sent or received. The base station device is connected to the core network, for example, in a wired manner (connected by a line including a wireless section depending on the situation), and is connected to other base station devices (not shown) via the core network. In addition, the core network is connected to an external network such as the Internet via a gateway, and the base station device can be connected to the external network via the core network. In addition, the core network is configured to include nodes of various core networks.

[0028] The base station device of this embodiment is configured to internally include a first portion (first control device) that performs control of a lower layer during communication and a portion (second control device) that performs control of an upper layer. Figure 1 In the embodiment, the first control device is represented by DU (Distributed Unit) / TRP (Transmission Receiver Point), and the second control device is represented by CU (Central Unit). In addition, the first control device is referred to as DU and the second control device is referred to as CU. Here, the DU of the present embodiment is configured to perform control of at least the physical (PHY) layer, and on the other hand, does not perform control above at least the radio resource control (RRC) layer. On the other hand, the CU is configured to perform control of layers including the RRC layer at a higher position than the DU. The CU can be connected to a DU, or it can be connected to a DU as shown in the figure. Figure 1 In addition, the line connecting the CU and DU is called the fronthaul line. The CU and DU can be connected as shown in FIG. Figure 1 The DUs may be directly connected as shown, or a switch (not shown) connecting multiple DUs may be connected to the CU, and the communication between the CU and each DU may be performed through control by the switch. In addition, when a switch is used, communication between DUs may be performed without passing through the CU. In addition, DUs and CUs (base station devices) and devices in the core network are collectively referred to as network devices below.

[0029] DU can form multiple beams through beamforming. Figure 1 As shown, by forming multiple beams by multiple DUs, the number of beams that can be formed by the base station device can be increased, resulting in the ability to accommodate more users and increase the overall throughput. On the other hand, if the number of users accommodated increases, the number of times paging messages are sent will also increase accordingly. At this time, for example, if all DUs of multiple base station devices assigned the same Tracking Area Code (TAC) send the same paging message at the same time, wireless resources will be occupied by the transmission of paging messages during this period. In addition, in this case, the probability that the paging message will interfere with communications in base station devices with the same TAC and base station devices with different TACs will increase.

[0030] In contrast, in the present embodiment, the terminal device monitors the beam to be used when establishing a connection with any base station device when it is in a non-connected state in which it is not connected to any base station device. In addition, the beam to be used when establishing a connection with a base station device is referred to as a connection object beam below. The terminal device reports information related to the connection object beam to the base station device that forms the connection object beam, for example, based at least on the situation that the connection object beam changes as the terminal device itself moves. Then, the network device (DU / CU or a node within the core network) performs limited control of the beam for sending paging messages based on the information.

[0031] In addition, the terminal device can perform reporting of information related to the connected object beam while maintaining the non-connected state. In addition, in LTE, RRC_Connected and RRC_Idle states are defined, but for example, a state in which a specified signal can be sent although an RRC connection has not been established can also be defined between the above states. In this case, the non-connected state here includes such a state in which a specified signal can be sent although an RRC connection has not been established.

[0032] In addition, the terminal device may further perform a report on information related to the connection object beam based on the number of times the connection object beam has changed in the non-connected state. For example, the terminal device may perform a report on the state related to the connection object beam at that moment every time the connection object beam changes a specified number of times, such as 3 times. In addition, the terminal device may report the connection object beam every time the connection object beam changes a specified number of times during the period when the non-connected state continues. That is, the terminal device may report when the connection object beam has changed a specified number of times since the last report, for example, when the non-connected state continues. In addition, once the terminal device becomes connected, the network device can track the beam used by the terminal device in the connection. Therefore, the terminal device can reset the number to 0 at the moment of transitioning to the connected state.

[0033] In addition, the terminal device may further perform a report on information related to the connection object beam based on the number of connection object beams that have been transformed in the non-connected state. For example, when the connection object beam is switched alternately between two beams, the terminal device counts the number of connection object beams that have been transformed as "2" regardless of the number of times. Then, when the number reaches a specified number such as "3", the connection object beam is reported. In addition, the terminal device may report the connection object beam each time the number of connection object beams that have been transformed reaches a specified number while the non-connected state continues. That is, the terminal device may report, for example, when the non-connected state continues, when a specified number of connection object beams have been transformed since the last report. In addition, the terminal device may reset the number to 0 at the moment of transformation to the connected state. In addition, the terminal device may use a combination of the number of transformations of the connection object beam and the number of connection object beams of the transformation target. For example, the terminal device may report the connection object beam when the number of transformations of the connection object beam reaches a specified number, or when the number of connection object beams of the transformation target reaches a specified number.

[0034] In addition, when the connection object beam changes in the non-connected state, the terminal device can report the connection object beam based on the fact that the DU providing the connection object beam before the change is different from the DU providing the connection object beam after the change. In addition, when the DU providing the connection object beam remains unchanged, the terminal device can report the connection object beam based on the number of changes of the connection object beam and the number of connection object beams of the change target as described above.

[0035] In addition, the conditions for the terminal device to report the connection object beam can be specified by the base station device. When the terminal device receives the condition from the base station device, it can report the connection object beam according to the condition. In addition, "received from the base station device" here also includes the case of receiving from a node of the core network via the base station device.

[0036] On the other hand, the network device (base station device (DU / CU) or a node of the core network) receives the above-mentioned report of the connection object beam from the terminal device. Then, the network device controls in the following manner: a part of the beams including the reported connection object beam among the multiple beams formed by more than one base station devices is used to perform paging to the terminal device. For example, the network device can control as follows: when the terminal device performs the above-mentioned report every time the connection object beam changes, paging is performed only in the reported connection object beam. In addition, the network device can control as follows: when the terminal device performs the above-mentioned report every time the connection object beam changes three times, paging is performed in the connection object beam, the first beam adjacent to the connection object beam, and the second beam adjacent to the first beam. In addition, the network device can control as follows: when the terminal device performs the above-mentioned report every time the number of connection object beams that change reaches three, paging is also performed in the connection object beam, the above-mentioned first beam, and the second beam. Furthermore, the network device may perform control such that, when the terminal device performs the above-mentioned report every time the DU providing the connection target beams before and after the transition is different, paging is performed in each beam provided by the DU providing the connection target beam after the transition.

[0037] In addition, for example, when the network device performing the above control is a node of the core network, a paging message is sent only to the DU that forms the beam for paging. Therefore, a paging message is not sent to a second CU different from the first CU to which the DU is connected and other DUs under the first CU. Therefore, the load on the backhaul line and the fronthaul line, and further the CU and DU that are not paging, can be reduced.

[0038] In addition, for example, when the network device performing the above-mentioned control is a CU, the node of the core network sends a paging message to, for example, a base station device (CU) having the same TAC. Moreover, the CU can send a paging message to the DU under its jurisdiction when the received paging message should be sent through the beam formed by the DU under its jurisdiction. Therefore, unnecessary waste of the fronthaul line can be prevented. In addition, since the paging message is not sent to the DU that is not paging, the load on many DUs can be reduced. Furthermore, the node of the core network manages the information of the beam to which the paging message should be sent, so that it is not necessary to manage the sending target of the paging message, thereby reducing the processing load.

[0039] In addition, for example, when the network device performing the above control is a DU, a node of the core network may send a paging message to a base station device (CU) having the same TAC, and the CU may forward the paging message to all subordinate DUs. Moreover, when the paging message should be sent through the beam formed by itself, the DU sends the paging message as a wireless signal. As a result, the nodes of the core network and the CU manage the information of the beam to which the paging message should be sent, so that it is not necessary to manage the sending target of the paging message, thereby reducing the processing load.

[0040] As described above, a terminal device in a non-connected state notifies the network side of information indicating which beam to use when establishing a connection as information of a connection target beam, whereby the network device uses only a portion of the beams for paging. This can prevent waste of wireless resources and suppress interference with communications under other beams.

[0041] The following describes the configuration of a terminal device and a network device that perform such processing, and the flow of processing.

[0042] (Hardware Configuration)

[0043] Figure 2 The following is an example of hardware configuration of a terminal device and a network device. In one example, the terminal device and the network device have Figure 2 The hardware configuration shown in the figure includes, for example, a CPU 201, a ROM 202, a RAM 203, an external storage device 204, and a communication line 205. In the terminal device and the network device, the CPU 201 executes a program for realizing the functions of the terminal device and the network device as described above, which is stored in any one of the ROM 202, the RAM 203, and the external storage device 204.

[0044] Furthermore, the terminal device and the network device communicate with other devices by, for example, controlling the communication line 205 through the CPU 201. In addition, the communication line 205 of the network device can communicate with other network devices through, for example, a wired line. In addition, when the network device is a DU, the communication line 205 can also form one or more (multiple) beams to perform wireless communication with the terminal device. In addition, the communication line 205 of the terminal device is configured to be connected to at least any one of the beams formed by the communication line 205 of the DU, and is configured to be able to perform wireless communication with the DU using the above-mentioned beam. In addition, in Figure 2In the configuration, a schematic diagram showing that the terminal device and the network device have one communication line 205 is shown, but it is not limited to this and may have multiple communication lines. For example, the DU has a first communication line for communication performed by a fronthaul line, and a second communication line for wireless communication. In addition, the CU may have a first communication line for communication performed by a fronthaul line, and a second communication line for communication with a core network. In addition, the terminal device may have a first communication line based on a wireless communication standard of a generation before the fourth generation, for example, and a second communication line based on a fifth generation wireless communication standard. In addition, the terminal device includes a wireless communication line related to standards other than cellular, such as a wireless LAN, and further, may have a wired communication line used for a wired connection, such as a USB connection.

[0045] Furthermore, the terminal device and the network device may have dedicated hardware for executing each function, or the hardware may execute a part of the functions, and a computer that runs a program may execute the other parts of the functions. In addition, the computer and the program may execute all the functions.

[0046] (Functional composition)

[0047] First, use Figure 3 An example of the functional configuration of the terminal device is described. In one example, the terminal device is configured to include a wireless communication unit 301, a connection object beam monitoring unit 302, and a report control unit 303. In addition, the terminal device is an electronic device having a general communication terminal or communication function other than this, and may have various functional units, but these functions are not illustrated here for the sake of simplicity.

[0048] The wireless communication unit 301 controls an antenna (not shown) and is configured to be connected to at least one of the multiple beams formed by one or more DUs in one or more base station devices. The wireless communication unit 301 can generate a baseband signal based on the data of the transmission object and the information generated by the report control unit 303, and convert the baseband signal into a radio frequency signal and output it from the antenna as a wireless signal. In addition, the wireless communication unit 301 can convert the wireless signal received via the antenna into a baseband signal and extract information from the baseband signal.

[0049] The connection object beam monitoring unit 302 monitors which beam among the beams formed by any base station in the base station apparatus becomes the connection object beam to be used when the connection is established, in an unconnected state in which no connection is established with any base station apparatus. In addition, for example, the connection here is an RRC connection, and the unconnected state is a state different from the RRC_Connected state. For example, the connection object beam monitoring unit 302 observes the wireless quality through a specified signal (such as a reference signal) sent from each beam, and determines the beam with the best wireless quality or a beam above a specified level as the connection object beam. In addition, the connection object beam monitoring unit 302 does not necessarily have to determine one beam as the connection object beam, and may determine multiple connection object beams, or may determine that there is no connection object beam according to the situation.

[0050] The report control unit 303 performs control for reporting information about the connection object beam obtained from the monitoring result performed by the connection object beam monitoring unit 302 to the base station device (network device). The report control unit 303 can control the wireless communication unit 301 to notify the base station device of information about the connection object beam, for example, on the condition that a transition to the connection object beam occurs in the non-connected state. In addition, the report control unit 303 can control the wireless communication unit 301 to notify the base station device of information about the connection object beam, for example, on the condition that the number of transitions to the connection object beam occurs in the non-connected state reaches a predetermined number of times. In addition, the report control unit 303 can control the wireless communication unit 301 to notify the base station device of information about the connection object beam, for example, on the condition that the number of beams to which the connection object beam is transitioned in the non-connected state reaches a predetermined number. In addition, the report control unit 303 can control the wireless communication unit 301 to notify the base station device of information about the connection object beam, for example, on the condition that the DU that provides the beam before the transition of the connection object beam in the non-connected state is different from the DU that provides the beam after the transition. In addition, the report control unit 303 may report the information related to the connection object beam according to the situation that the non-connected state has remained unchanged for a predetermined period of time since the time when the information related to the connection object beam was previously reported. In addition, the above conditions are just examples, and the report control unit 303 may control the wireless communication unit 301 to report the information related to the connection object beam based on a combination of the above conditions or other conditions. In addition, the report control unit 303 may receive the conditions for reporting the information related to the connection object beam from the network device via the wireless communication unit 301.

[0051] In addition, the report of information related to the connection object beam can be sent, for example, by establishing an RRC connection, but can also be sent in a state where the RRC connection has not been established (non-connected state). For example, as an intermediate state between the RRC_Connected state and the RRC_idle state, a state in which a specified signal can be sent even though the RRC connection has not been established is defined, and information related to the connection object beam can be reported in this intermediate state.

[0052] In addition, the report control unit 303 can establish an RRC connection and send information related to the connection target beam to the DU after the transition, for example, when the TAC of the base station device to which the DU before the transition belongs and the TAC of the base station device to which the DU after the transition belongs are different.

[0053] Next, use Figure 4 An example of the functional configuration of a network device is described. As described above, the network device is, for example, a node of a core network, a CU or a DU in a base station device, but is not limited to any one of them. Therefore, the following focuses on the functional units used to perform the functions involved in this embodiment, and the description of the functions inherent to each of the above-mentioned devices is omitted. The network device is configured to include, for example, a communication unit 401, a connection object beam information acquisition unit 402, a call control unit 403, and a condition notification unit 404.

[0054] The communication unit 401 is configured to control an antenna not shown in the figure and form more than one beam, for example, when the network device is a DU, and can connect to the terminal device using at least one of the above beams. In addition, the communication unit 401 is configured to communicate with other DUs through a fronthaul line via a CU and a switch configured between the CU and the DU, or via a switch, when the network device is a DU. In addition, when the network device is a CU, the communication unit 401 can communicate with nodes in the core network and CUs in other base station devices through a backhaul line, and can communicate with subordinate DUs through a fronthaul line. In addition, when the network device is a node of the core network, the communication unit 401 can communicate with the CU in the base station device through a backhaul line.

[0055] The connection object beam information acquisition unit 402 acquires information related to the connection object beam reported by the terminal device. For example, when the network device is a DU, the connection object beam information acquisition unit 402 directly acquires information related to the connection object beam from the terminal device through a wireless signal. When the network device is a CU, the connection object beam information acquisition unit 402 acquires information related to the connection object beam received and forwarded by the DU from the terminal device. In addition, when the network device is a node of the core network, the connection object beam information acquisition unit 402 acquires information related to the connection object beam received by the DU from the terminal device and forwarded to the CU and further forwarded by the CU.

[0056] The call control unit 403 determines a part of the beam based on the information related to the connection object beam obtained, and performs control for calling (paging) the terminal device through the determined beam. As a result, paging messages are not sent unnecessarily in more beams, the utilization efficiency of wireless resources can be improved, and interference of paging messages with other signals can be avoided.

[0057] In order to perform such control, the call control unit 403 stores and manages information that identifies a terminal device in association with a connection target beam reported from the terminal device. For example, when the network device is a node of a core network, the call control unit 403 manages information about a terminal device that uses a beam that can be formed by all base station devices under its control as a connection target beam together with the connection target beam. In addition, when the network device is a CU, for example, the call control unit 403 manages information about a terminal device that uses a beam that can be formed by a DU under its control as a connection target beam together with the connection target beam. In addition, when the network device is a DU, for example, the call control unit 403 manages information about a terminal device that uses any of the beams formed by itself as a connection target beam together with the connection target beam.

[0058] Moreover, when executing a call to a certain terminal device, the call control unit 403, for example, determines the connection object beam corresponding to the terminal device and determines the DU that forms the determined beam when executing a call to the terminal device. Then, the call control unit 403 sends a paging message specifying the determined beam to the CU having the DU under its jurisdiction. When the CU receives the paging message, it forwards the paging message to the DU that forms the specified beam, causing the DU to send the paging message as a wireless signal. In this case, the paging message is not sent to the CU of the base station device that does not send the paging message, thereby reducing the processing load of the CU and reducing the communication volume in the backhaul line.

[0059] On the other hand, in the case where the network device is a CU, the node of the core network sends a paging message containing information indicating which terminal device the message is sent to to all subordinate CUs. Then, when the call control unit 403 in the CU receives the paging message from the node of the core network, it determines whether it manages the terminal device to which the paging message is sent. Then, when the call control unit 403 manages the terminal device to which the message is sent, it forwards the paging message to the DU that forms the connection object beam corresponding to the terminal device, and causes the DU to send the paging message as a wireless signal. In this case, the node of the core network does not perform processing corresponding to the connection object beam, so paging can be performed with a smaller processing load. In addition, the paging message is not sent to the DU that does not send the paging message, so the processing load of each DU can be reduced, and the communication volume in the fronthaul line can be reduced.

[0060] In addition, when the network device is a DU, the node of the core network sends a paging message containing information indicating which terminal device the message is sent to to all subordinate CUs. In addition, the CU forwards the paging message to all subordinate DUs. Then, when receiving the paging message, the call control unit 403 in the DU determines whether it manages the terminal device to which the paging message is sent. Then, when the call control unit 403 manages the terminal device to which the paging message is sent, it sends the paging message as a wireless signal through the connection object beam corresponding to the terminal device. In this case, the nodes and CUs of the core network do not perform processing corresponding to the connection object beam, so paging can be performed with a smaller processing load.

[0061] In addition, the call control unit 403 does not send paging messages only in the connection object beam, but can also send paging messages in beams that leave the specified range from the beam. For example, when the call control unit 403 pre-constructs multiple groups including more than one beam, it can be controlled to send paging messages in all or part of the beams included in the group. In addition, the call control unit 403 can determine the range of the beam to which the paging message should be sent based on the reporting conditions of the connection object beam (the number of transitions of the connection object beam / the number of transition targets / the transition of the connection target DU, etc.). For example, the call control unit 403 can send a paging message in the connection object beam and its adjacent beams when reporting is performed every time the connection object beam transitions twice or every time the number of transition targets of the connection object beam reaches three. In addition, when the DUs before and after the transition corresponding to the connection object beam are different, the call control unit 403 can send a paging message in the beam that can be formed by the DU after the transition.

[0062] The condition notification unit 404 notifies the terminal device of the reporting condition of the information on the connection target beam. In addition, when the reporting condition is determined in advance, the condition notification unit 404 can be omitted.

[0063] In addition, some functions may be distributed among multiple network devices, for example. For example, the call control unit 403 may be distributed among the nodes or CUs and DUs of the core network, and the nodes or CUs of the core network manage the information of the DUs that form the connection object beams according to each terminal device, and the DUs manage the information of the connection object beams corresponding to the terminal devices. Furthermore, the nodes or CUs of the core network may send a paging message to the DUs corresponding to the terminal devices, and the DUs may send the paging message through one or more beams including the beams corresponding to the terminal devices.

[0064] (Processing flow)

[0065] Next, the process flow of the processing executed by the terminal device and the network device as described above is described. Figure 5 The following describes an example in which the network device is a DU. In addition, in this example, in order to simplify the description, only DU1 forming beam group A and CU1 under which DU1 is placed, DU2 forming beam group B and CU2 under which DU2 is placed, and the nodes of the core network (in Figure 5 However, there may be multiple CUs that each has multiple DUs under it. In addition, for example, different core network nodes may be configured for different TACs.

[0066] First, the terminal device stays within the range of beam group A (S501), and the connection target beam of the terminal device is set to a beam in beam group A. At this time, for example, DU1 can notify the reporting conditions of the connection target beam (S502). After that, it is assumed that the terminal device satisfies the reporting conditions of the connection target beam, such as the number of transitions of the connection target beam reaching a specified number of times, while remaining within the range of beam group A in a non-connected state (S503). Then, the terminal device notifies DU1 of the information related to the connection target beam at that moment (S504). DU1 associates the reported connection target beam with the information identifying the terminal device and stores and manages them (S505).

[0067] After that, it is assumed that the terminal device moves within the range of beam group B while maintaining the non-connected state and satisfies the reporting condition of the connection target beam (S506). For example, when the reporting condition is that the DUs providing the connection target beams before and after the transition are different, the terminal device satisfies the reporting condition of the connection target beam when it moves within the range of beam group B. In this case, the terminal device reports information related to the connection target beam to DU2 (S507). Then, DU2 associates the reported connection target beam with the information identifying the terminal device and stores and manages it (S508).

[0068] At this time, notifications for updating information for associating the connection object beam and the terminal device can be sent and received between DU2 and DU1. For example, DU2 notifies DU1 of the updated information (for example, via CU2 and CU1). In addition, DU1 can determine that the terminal device no longer exists within the range of beam group A based on, for example, the fact that no report on the connection object beam is received within a specified period. Thus, DU1 can know that the terminal device no longer exists within the range of beam group A formed by itself, so that unnecessary paging messages can be avoided.

[0069] Afterwards, it is assumed that paging for the terminal device occurs. In this case, the node of the core network first sends a paging message (S509) to CU1 and CU2, which are CUs of the base station devices belonging to the TAC managed by itself. Then, CU1 and CU2 forward the paging message to DU1 and DU2, respectively (S510). DU2 sends the paging message as a wireless signal because the terminal device exists within the range of beam group B formed by itself (S511). On the other hand, since the terminal device does not exist within the range of beam group A, DU1 does not send a paging message.

[0070] Next, use Figure 6 An example in which the network device is a CU is described. First, the terminal device stays within the range of beam group A (S601), and the connection object beam of the terminal device is set to a beam in beam group A. At this time, for example, the reporting condition of the connection object beam can be notified from CU1 via DU1 (S602). Afterwards, it is assumed that the terminal device satisfies the reporting condition of the connection object beam while remaining within the range of beam group A in a non-connected state (S603). Then, the terminal device notifies DU1 of information related to the connection object beam at that moment, and DU1 forwards the information to CU1 (S604). CU1 stores and manages the reported connection object beam in association with the information that identifies the terminal device (S605).

[0071] After that, it is assumed that the terminal device moves within the range of beam group B while maintaining the non-connected state and satisfies the reporting condition of the connection target beam (S606). In this case, the terminal device reports information related to the connection target beam to DU2, and DU2 forwards the information to CU2 (S607). Then, CU2 associates the reported connection target beam with the information identifying the terminal device and stores and manages them (S608).

[0072] At this time, notifications for updating information for associating the connection object beam and the terminal device can be sent and received between CU2 and CU1. For example, CU2 can notify CU1 of the updated information (for example, via the core network). In addition, CU1 can determine that the terminal device no longer exists within the range of beam group A based on, for example, the fact that no report on the connection object beam is received within a specified period. Thus, CU1 can know that the terminal device no longer exists within the range of beam group A formed by its subordinate DU1, so that unnecessary paging messages can be avoided.

[0073] Afterwards, it is assumed that paging for the terminal device occurs. In this case, the node of the core network first sends a paging message (S609) to CU1 and CU2, which are CUs of the base station devices belonging to the TAC managed by itself. Then, CU2 forwards the paging message to DU2 because the terminal device exists within the range of beam group B formed by DU2 under its own jurisdiction (S610). On the other hand, since the terminal device does not exist within the range of beam group A formed by DU1 under its own jurisdiction, the paging message is not forwarded to DU1. Afterwards, DU2 sends the forwarded paging message as a wireless signal (S611). On the other hand, since DU1 will not receive the paging message, it will not send the paging message.

[0074] In addition, Figure 6In the example, it is shown that only the CU manages the terminal device and its corresponding connection object beam in association, but the control can be decentralized by the CU and the DU. For example, the CU can store the information of the terminal device and the DU that provides the connection object beam in association, and the DU can store the terminal device and the connection object beam in association. For example, CU1 manages the terminal device and DU1 in association in S605, and DU1 manages the terminal device and the connection object beam in association. In addition, CU2 manages the terminal device and DU2 in association in S608, and DU2 manages the terminal device and the connection object beam in association. Thus, for example, when CU1 and CU2 receive a paging message, they can appropriately control whether to forward the paging message to their own subordinate DUs. In addition, CU1 and CU2 do not need to manage all the connection object beams, so the amount of information managed is reduced, and it is sufficient to receive only the information of the terminal device from the DU, so the amount of information to be sent and received in the fronthaul line can be reduced. In addition, the beam for sending paging messages can be appropriately limited in the DU, thereby suppressing the sending of unnecessary paging messages.

[0075] Next, use Figure 7 An example in which the network device is a node of the core network is described. First, the terminal device stays within the range of beam group A (S701), and the connection object beam of the terminal device is set to a beam in beam group A. At this time, for example, the reporting condition of the connection object beam can be notified from the node of the core network via CU1 and DU1 (S702). Afterwards, it is assumed that the terminal device satisfies the reporting condition of the connection object beam while remaining within the range of beam group A in a non-connected state (S703). As a result, the terminal device notifies DU1 of information related to the connection object beam at that moment, and DU1 forwards the information to CU1, and further, CU1 forwards the information to the node of the core network (S704). The node of the core network associates the reported connection object beam with the information that identifies the terminal device for storage and management (S705).

[0076] After that, it is assumed that the terminal device moves within the range of beam group B while maintaining the non-connected state and satisfies the reporting condition of the connection target beam (S706). In this case, the terminal device reports information related to the connection target beam to DU2, DU2 forwards the information to CU2, and CU2 forwards the information to the node of the core network (S707). Then, the node of the core network associates the reported connection target beam with the information identifying the terminal device and stores and manages it (S708).

[0077] Afterwards, it is assumed that paging for the terminal device occurs. In this case, since the terminal device exists within the range of beam group B formed by DU2, the node of the core network sends a paging message to CU2 having DU2 under its subordinates (S709). On the other hand, since the terminal device does not exist within the range of the beam group formed by the DU under CU1, the node of the core network does not send a paging message to CU1. Then, CU2 forwards the received paging message to its own subordinate DU2 (S710). Afterwards, DU2 sends the forwarded paging message as a wireless signal (S711). On the other hand, since CU1 and DU1 will not receive the paging message, the paging message will not be sent from DU1.

[0078] In addition, Figure 7 In the example, it is shown that only the node of the core network manages the terminal device and its corresponding connection object beam in association, but for example, the control can be decentralized by the node of the core network and the CU or DU. For example, the node of the core network can store the information of the terminal device and the DU providing the connection object beam or the CU having the DU under it in association, and the CU or DU can store the terminal device and the connection object beam in association. For example, the node of the core network manages the terminal device and DU1 (or CU1) in association in S705, and DU1 (or CU1) manages the terminal device and the connection object beam in association. In addition, the node of the core network manages the terminal device and DU2 (or CU2) in association in S708, and DU2 (or CU2) manages the terminal device and the connection object beam in association. Thus, for example, the node of the core network can appropriately limit the CU to which the paging message is sent. In addition, the core network node does not need to manage all the beams to be connected, so the amount of information to be managed is reduced, and it is sufficient to receive only the information of the terminal device from the DU (or CU), so the amount of information to be sent and received can be reduced. In addition, the beam to send the paging message can be appropriately limited in the DU (or CU), thereby suppressing the sending of unnecessary paging messages.

[0079] As described above, in this embodiment, the terminal device monitors the beam of the connection object to be used when connected to the base station device in the non-connected state, and notifies the network device of information related to the connection object beam. Then, the network device can use part of the available beams based on the notification to perform paging for the terminal device. In this way, it is possible to prevent paging messages from being sent unnecessarily through more beams, thereby improving the utilization efficiency of wireless resources and suppressing interference with other signals.

[0080] The present invention is not limited to the above-described embodiments, and various changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to disclose the scope of the present invention.

[0081] This application claims priority based on Japanese Patent Application No. 2016-189443 filed on September 28, 2016, the entire contents of which are incorporated herein by reference.

Claims

1. A terminal device, which is a terminal device capable of connecting to one or more base station devices that respectively form one or more beams, and capable of operating in any of a first state (an RRC_connected state), a second state (an RRC_idle state), and a third state different from both the first state and the second state, characterized in that: The terminal device comprises: a setting unit that, in the third state, sets a connection target beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices; as well as a reporting unit that reports information related to the connection object beam to the base station device that forms the connection object beam based on the fact that the connection object beam has changed within the range of the tracking area, The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

2. The terminal device according to claim 1, characterized in that The reporting unit reports the information on the connection target beam without changing to the first state.

3. The terminal device according to claim 1, characterized in that The setting unit sets one or more beams in the tracking area as the connection target beams.

4. The terminal device according to claim 1, characterized in that: The setting unit sets a beam that does not exceed the range of the tracking area as the connection target beam.

5. The terminal device according to claim 1, characterized in that: The one or more base station devices each include one or more devices that respectively perform physical layer control and are capable of forming one or more beams, The reporting unit reports information on the connection target beam when the device that forms the connection target beam before the change and the device that forms the connection target beam after the change are different.

6. The terminal device according to any one of claims 1 to 5, characterized in that: The terminal device further includes a receiving unit configured to receive, from at least one of the one or more base station devices, a condition under which the reporting unit reports the information on the connection target beam.

7. A network device, comprising: a network device in a network including one or more base station devices each forming one or more beams, characterized in that: The network device has: a receiving unit for receiving a report from a terminal device capable of connecting to the one or more base station devices and capable of operating in any one of an RRC_connected state, i.e., a first state, an RRC_idle state, i.e., a second state, and a third state different from both the first state and the second state, wherein the connection object beam has changed within the range of the tracking area in the third state, the report being a report related to the connection object beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices; as well as a control unit configured to perform paging on the terminal device using a portion of beams including the connection target beam among a plurality of beams formed by the one or more base station devices, The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

8. The network device according to claim 7, characterized in that: The network device is a node of a core network connected to each of the one or more base station devices.

9. The network device according to claim 7, characterized in that: The network device is the second device among a first device respectively contained in the one or more base station devices, which performs control of layers including a physical layer at a position lower than the RRC layer, and a second device which performs control of layers including the RRC layer at a position higher than the layers controlled by the first device.

10. The network device according to claim 7, characterized in that: The network device is the first device contained in the one or more base station devices, which performs control of layers including the physical layer at a position lower than the RRC layer, and the second device that performs control of layers including the RRC layer at a position higher than the layers controlled by the first device.

11. The network device according to any one of claims 7 to 10, characterized in that: The network device further includes a notification unit that notifies the terminal device of a condition for performing a report related to the connection target beam.

12. A control method is a control method performed by a terminal device, the terminal device can be connected to one or more base station devices that form one or more beams respectively, and can operate in any one of an RRC_connected state, i.e., a first state, an RRC_idle state, i.e., a second state, and a third state different from both the first state and the second state, characterized in that: The control method comprises the following steps: a setting step in which, in the third state, a connection target beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices is set; and a reporting step, in which, based on the fact that the connection object beam has changed within the scope of the tracking area, information related to the connection object beam is reported to the base station device forming the connection object beam, The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

13. A control method, executed by a network device in a network including one or more base station devices each forming one or more beams, characterized in that: The control method comprises the following steps: A receiving step, in which a report is received from a terminal device that is capable of connecting to the one or more base station devices and is capable of operating in any one of an RRC_connected state, i.e., a first state, an RRC_idle state, i.e., a second state, and a third state different from both the first state and the second state, wherein a connection object beam has changed within the range of a tracking area in the third state, the report being related to the connection object beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices; as well as a control step in which the terminal device is paged using a portion of the beams including the connection target beam among the plurality of beams formed by the one or more base station devices; The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

14. A computer-readable storage medium storing a program for causing a computer of a terminal device capable of connecting to one or more base station devices that respectively form one or more beams and capable of operating in any one of an RRC_connected state (a first state), an RRC_idle state (a second state), and a third state different from both the first state and the second state to execute the following contents: In the third state, a connection target beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices is set; and Based on the fact that the connection target beam has changed within the tracking area, information related to the connection target beam is reported to the base station device forming the connection target beam, The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

15. A computer-readable storage medium storing a program for causing a computer included in a network device including one or more base station devices each forming one or more beams to execute the following contents: receiving a report from a terminal device that is capable of connecting to the one or more base station devices and that is capable of operating in any one of an RRC_connected state, i.e., a first state, an RRC_idle state, i.e., a second state, and a third state different from both the first state and the second state, wherein a connection object beam has changed within the range of a tracking area in the third state, the report being a report related to the connection object beam to be used by the terminal device when establishing a connection with any one of the one or more base station devices; and controlling to page the terminal device using a portion of beams including the connection target beam among a plurality of beams formed by the one or more base station devices, The third state is a state in which a predetermined signal can be transmitted although an RRC connection has not been established.

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