Communication device, base station, and communication method

Abstract

To provide a communication device, a base station, and a communication method that enable appropriate execution of measurements in accordance with a measurement mitigation method.MEANS FOR SOLVING THE PROBLEM: According to an embodiment, a communication device selects to perform mitigation measurements when a criterion for stationary and a criterion for non-cell edge are satisfied based on third information, in an RRC idle state or an RRC inactive state. The communication device determines, in the RRC idle state or the RRC inactive state, whether the criterion for stationary is satisfied during a period in which fluctuations in received level values applied to the criterion for stationary are evaluated, receives, in an RRC connected state, setting information from a base station for setting the communication device to provide information indicating whether the communication device is in a stationary state in the RRC connected state, and starts transmitting a UE assistance information message including information indicating whether the communication device is in the stationary state in response to a change in the stationary state.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] The present invention relates to a communication device, a base station, and a communication method.

Background Art

[0002] In recent years, in 3GPP (registered trademark; the same shall apply hereinafter) (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, it has been considered to provide a specific user device having reduced communication capabilities compared to general user devices in a 5G system (see Non-Patent Document 1). The specific user device is a user device having mid-range performance and price for IoT (Internet of Things), and for example, compared to general user devices, the maximum bandwidth used for wireless communication is set narrower, or the number of receivers is smaller.

[0003] Also, it has been agreed to introduce a method of relaxing the measurement of radio quality for adjacent cells based on an RSRP (Reference Signal Received Power) / RSRQ (Reference Signal Received Quality) based stationarity criterion for a specific user device in the RRC connected state (so-called RRM relaxation; hereinafter, appropriately referred to as a measurement relaxation method) (see Non-Patent Document 2).

[0004] Since a stationary specific user device has little variation in the radio environment, a specific user device that does not need to frequently perform the measurement of radio quality for adjacent cells can reduce the number of measurements by the measurement relaxation method by being regarded as a stationary user device when it satisfies the stationarity criterion. Thereby, power saving and improvement of battery life can be achieved.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the current 3GPP specification does not have provisions regarding the stationary reference, and there is a concern that a specific user device may not be able to appropriately execute measurements according to the measurement relaxation method. In addition, there is a similar concern for general user devices when a measurement relaxation method based on the stationary reference is introduced.

[0007] Therefore, an object of the present invention is to provide a user device, a base station, and a communication method that can appropriately execute measurements according to the measurement relaxation method based on the stationary reference.

Means for Solving the Problems

[0008] The communication device according to the first aspect includes a receiving unit (121) that receives, in a radio resource control (RRC) idle state or an RRC inactive state, first information regarding a stationary criterion, information for specifying a period during which fluctuations in a reception level value applied to the stationary criterion are evaluated, second information regarding a non-cell-edge criterion, and third information instructing to execute relaxed measurement when the stationary criterion and the non-cell-edge criterion are satisfied, from a base station (200); and a control unit (140) that selects, in the RRC idle state or the RRC inactive state, execution of the relaxed measurement when the stationary criterion and the non-cell-edge criterion are satisfied, based on the third information. The control unit determines, in the RRC idle state or the RRC inactive state, whether the stationary criterion is satisfied during a period in which fluctuations in the reception level value applied to the stationary criterion are evaluated. The receiving unit is set to receive, in an RRC connected state, setting information for providing information indicating whether the device is in a stationary state in the RRC connected state, from the base station. The control unit starts transmission of a UE assistance information message including information indicating whether the device is in the stationary state, in response to a change in the stationary state, when the setting information is received in the RRC connected state.

[0009] The base station according to the second aspect includes a transmission unit that transmits to a communication device (100) in a radio resource control (RRC) idle state or an RRC inactive state, first information regarding a stationary reference, information for designating a period during which fluctuations in a reception level value applied to the stationary reference are evaluated, second information regarding a non-cell-edge reference, and third information for instructing to execute relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied; a control unit that controls the communication device in the RRC idle state or the RRC inactive state to select execution of the relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied, based on the third information; and a reception unit. Whether the stationary reference is satisfied is determined in the communication device in the RRC idle state or the RRC inactive state during a period in which fluctuations in the reception level value applied to the stationary reference are evaluated. The transmission unit transmits setting information for setting to provide information indicating whether the communication device is in a stationary state in the RRC connected state, to the communication device in the RRC connected state. The reception unit receives, from the communication device in the RRC connected state, a UE assistance information message including information indicating whether the communication device is in the stationary state, which is transmitted in response to a change in the stationary state, when the setting information is transmitted.

[0010] The communication method according to the third aspect is a communication method executed by a communication device (100). In the radio resource control (RRC) idle state or the RRC inactive state, first information regarding a stationary criterion, information for specifying a period during which fluctuations in a reception level value applied to the stationary criterion are evaluated, second information regarding a non-cell-edge criterion, and third information for instructing to execute relaxed measurement when the stationary criterion and the non-cell-edge criterion are satisfied are received from a base station (200). In the RRC idle state or the RRC inactive state, based on the third information, when the stationary criterion and the non-cell-edge criterion are satisfied, a step of selecting to execute the relaxed measurement is performed. In the RRC connected state, a step of receiving setting information from the base station for setting to provide information indicating whether the state is stationary in the RRC connected state is performed. In the RRC connected state, when the setting information is received, a step of starting transmission of a UE assistance information message including information indicating whether the state is stationary in response to a change in the stationary state is performed. In the step of selecting to execute the relaxed measurement, it is determined whether the stationary criterion is satisfied during a period in which fluctuations in the reception level value applied to the stationary criterion are evaluated.

[0011] The communication method according to the fourth aspect is a communication method executed by a base station (200), including: first information regarding a stationary reference, information for designating a period during which fluctuations in a reception level value applied to the stationary reference are evaluated, second information regarding a non-cell-edge reference, and third information for instructing to execute relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied. The method includes transmitting the above information to a communication device (100) in an RRC idle state or an RRC inactive state, controlling the communication device in the RRC idle state or the RRC inactive state to select execution of the relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied based on the third information, transmitting setting information for setting to provide information indicating whether the communication device is in a stationary state in the RRC connected state to the communication device in the RRC connected state, and receiving a UE assistance information message including information indicating whether the communication device is in the stationary state transmitted in response to a change in the stationary state when the setting information is transmitted, from the communication device in the RRC connected state. Whether the stationary reference is satisfied is determined in the communication device in the RRC idle state or the RRC inactive state during a period in which fluctuations in the reception level value applied to the stationary reference are evaluated.

Advantages of the Invention

[0012] According to one aspect of the present invention, it is possible to provide a user device and a communication method that can appropriately execute measurements according to a measurement relaxation method based on a stationary reference.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Mode for Carrying Out the Invention

[0014] The mobile communication system according to the embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0015] (System Configuration) First, with reference to FIG. 1, the configuration of the mobile communication system 1 according to the present embodiment will be described. The mobile communication system 1 is a system compliant with, for example, the technical specifications (Technical Specification: TS) of 3GPP. Hereinafter, as the mobile communication system 1, a fifth-generation system (5th Generation System: 5GS) of the 3GPP standard, that is, a mobile communication system based on NR (New Radio) will be described as an example.

[0016] The mobile communication system 1 includes a network 10 and a user equipment (UE) 100 that communicates with the network 10. The network 10 includes an NG-RAN (Next Generation Radio Access Network) 20 which is a 5G radio access network and a 5GC (5G Core Network) 30 which is a 5G core network.

[0017] UE100 is a device used by a user. UE100 is a movable device such as, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a notebook PC, a communication module, or a communication card. UE100 may be a vehicle (e.g., a car, a train, etc.) or a device provided thereon. UE100 may be a transport aircraft other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided thereon. UE100 may be a sensor or a device provided thereon. Note that UE100 may be called by another name such as a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit.

[0018] In the present embodiment, as the NR UE100, two types of UEs are assumed: a general UE100A and a specific UE100B having a reduced communication capability compared to the general UE100A. The general UE100A has advanced communication capabilities such as enhanced Mobile Broadband (eMBB) and Ultra-Reliable and Low Latency Communications (URLLC), which are characteristics of NR. The specific UE100B is a UE with reduced device cost and complexity compared to the general UE100A. The specific UE100B is a UE having middle-range performance / price for the IoT, and for example, has a narrower maximum bandwidth used for wireless communication or fewer receivers compared to the general UE100A. Note that a receiver may be referred to as a receiving branch. The specific UE100B may be referred to as a Reduced capability NR device or a RedCap UE.

[0019] Specifically, the specific UE 100B may be capable of communicating at a communication speed equal to or higher than the communication speed defined by the LPWA (Low Power Wide Area) standard, for example, LTE Cat.1 / 1bis, LTE Cat.M1 (LTE-M), or LTE Cat.NB1 (NB-IoT). The specific UE 100B may be capable of communicating with a bandwidth equal to or higher than the bandwidth defined by the LPWA standard. Compared with Rel-15 or Rel-16 UEs, the bandwidth used for communication by the specific UE 100B may be limited. For example, for FR1 (Frequency Range 1), the maximum bandwidth of the specific UE 100B may be 20 MHz. Also, for FR2 (Frequency Range 2), for example, the maximum bandwidth of the specific UE 100B may be 100 MHz. The specific UE 100B may have only one receiver for receiving radio signals. The specific UE 100B may be, for example, a wearable device or a sensor device, etc.

[0020] The NG-RAN 20 includes a plurality of base stations 200. Each base station 200 manages at least one cell. A cell constitutes the smallest unit of a communication area. One cell belongs to one frequency (carrier frequency). The term "cell" may represent radio communication resources and may also represent the communication target of the UE 100. Each base station 200 can perform radio communication with the UE 100 located in its cell. The base station 200 communicates with the UE 100 using the RAN protocol stack. Details of the protocol stack will be described later. Also, the base station 200 is connected to other base stations 200 (which may be referred to as adjacent base stations) via the Xn interface. The base station 200 communicates with adjacent base stations via the Xn interface. Also, the base station 200 provides the NR user plane and control plane protocol termination towards the UE 100 and is connected to the 5GC 30 via the NG interface. Such an NR base station 200 may be referred to as a gNodeB (gNB).

[0021] 5GC30 includes a core network device 300. The core network device 300 includes, for example, an AMF (Access and Mobility Management Function) and / or a UPF (User Plane Function). The AMF performs mobility management of the UE100. The UPF provides functions specialized for U-plane processing. The AMF and the UPF are connected to the base station 200 via an NG interface.

[0022] (Protocol stack configuration example) Next, with reference to FIG. 2, a configuration example of the protocol stack according to the present embodiment will be described.

[0023] The protocol of the radio section between the UE100 and the base station 200 has a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an RRC layer.

[0024] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Between the PHY layer of the UE100 and the PHY layer of the base station 200, data and control information are transmitted via a physical channel.

[0025] The MAC layer performs priority control of data, retransmission processing by hybrid ARQ (HARQ), and a random access procedure, etc. Between the MAC layer of the UE100 and the MAC layer of the base station 200, data and control information are transmitted via a transport channel. The MAC layer of the base station 200 includes a scheduler. The scheduler determines the uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and the resources allocated to the UE100.

[0026] The RLC layer transmits data to the RLC layer on the receiving side by utilizing the functions of the MAC layer and the PHY layer. Between the RLC layer of UE100 and the RLC layer of the base station 200, data and control information are transmitted via logical channels.

[0027] The PDCP layer performs header compression / expansion and encryption / decryption.

[0028] An SDAP (Service Data Adaptation Protocol) layer may be provided as the upper layer of the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer performs the mapping between the IP flow, which is the unit for the core network to perform QoS control, and the radio bearer, which is the unit for the AS (Access Stratum) to perform QoS control.

[0029] The RRC layer controls logical channels, transport channels, and physical channels in response to the establishment, re - establishment, and release of radio bearers. Between the RRC layer of UE100 and the RRC layer of the base station 200, RRC signaling for various settings is transmitted. When there is an RRC connection between the RRC of UE100 and the RRC of the base station 200, UE100 is in the RRC connected state. When there is no RRC connection between the RRC of UE100 and the RRC of the base station 200, UE100 is in the RRC idle state. When the RRC connection between the RRC of UE100 and the RRC of the base station 200 is suspended, UE100 is in the RRC inactive state.

[0030] The NAS layer located above the RRC layer in UE100 performs session management and mobility management of UE100. Between the NAS layer of UE100 and the NAS layer of the core network device 300, NAS signaling is transmitted.

[0031] Note that UE100 has an application layer etc. in addition to the protocols of the radio interface.

[0032] (Configuration of User Equipment) Next, with reference to FIG. 3, the configuration of the UE 100 according to the present embodiment will be described. The UE 100 includes a communication unit 120 and a control unit 140.

[0033] The communication unit 120 performs wireless communication with the base station 200 by transmitting and receiving wireless signals to and from the base station 200. The communication unit 120 includes at least one receiving unit 121 and at least one transmitting unit 122. The receiving unit 121 and the transmitting unit 122 may be configured to include an antenna and an RF circuit. The antenna converts a signal into a radio wave and radiates the radio wave into space. Also, the antenna receives a radio wave in space and converts the radio wave into a signal. The RF circuit performs analog processing of the signal transmitted and received via the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, and the like.

[0034] The receiving unit 121 may be referred to as a receiver (RX). The transmitting unit 122 may be referred to as a transmitter (TX). When the UE 100 is the general UE 100A, the number of receivers included in the communication unit 120 may be two to four. When the UE 100 is the specific UE 100B, the number of receivers included in the communication unit 120 may be one or two.

[0035] The control unit 140 performs various controls in the UE 100. The control unit 140 controls communication with the base station 200 via the communication unit 120. Operations of the UE 100 described later may be operations under the control of the control unit 140. The control unit 140 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operations of the control unit 140. The control unit 140 may include a digital signal processor that performs digital processing of signals transmitted and received via an antenna and an RF circuit. The digital processing includes processing of the RAN protocol stack. Note that the memory stores a program executed by the processor, parameters related to the program, and data related to the program. The memory may include at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), a RAM (Random Access Memory), and a flash memory. All or part of the memory may be included in the processor.

[0036] In the UE 100 configured as described above, the communication unit 120 is used as a criterion for selecting whether to perform measurements according to a measurement relaxation method for relaxing measurements of radio quality with respect to adjacent cells, and is applied to a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state. The communication unit 120 receives a stationary threshold value from the serving cell. The control unit 140 measures at least one of the received power and the received quality as the radio quality of the serving cell. The control unit 140 determines whether the stationary criterion is satisfied based on the measurement result of the radio quality and the stationary threshold value. Thereby, the control unit 140 can appropriately execute measurements according to the measurement relaxation method by determining whether the stationary criterion is satisfied based on the measurement result of the radio quality and the stationary threshold value.

[0037] When the control unit 140 includes a quality threshold value compared with a value calculated based on the reception quality, regardless of whether it includes a power threshold value compared with a value calculated based on the reception power, it may determine whether the stationary criterion is satisfied based on the quality threshold value. Thereby, for example, compared with the case of determining whether the stationary criterion is satisfied based on the reception power, it is possible to determine whether the stationary criterion is satisfied in consideration of the influence of communication quality due to interference and noise.

[0038] When the control unit 140 includes a quality threshold value compared with a value calculated based on the reception quality and a power threshold value compared with a value calculated based on the reception power, it may determine whether the stationary criterion is satisfied based on the quality threshold value and the power threshold value. Thereby, since it is possible to determine whether the stationary criterion is satisfied based on both the reception quality and the reception power, when the radio quality is poor, the stationary criterion will not be satisfied. Therefore, it becomes possible to appropriately execute the measurement according to the measurement relaxation method.

[0039] When the control unit 140 does not include the quality threshold value but includes the power threshold value, it may determine whether the stationary criterion is satisfied based on the power threshold value. Thereby, for example, in an environment such as an isolated cell where there is no interference from adjacent cells and the traffic of its own cell is also low, the stationary state can be appropriately determined only by the determination based on the reception power.

[0040] When it is determined that the stationary criterion is satisfied, the communication unit 120 may transmit a message indicating that the stationary criterion has been satisfied to the serving cell. Thereby, the network can know that the UE 100 has satisfied the stationary criterion.

[0041] When it is determined that the stationary criterion is satisfied, the control unit 140 may select to execute the measurement on adjacent cells according to the measurement relaxation method. Thereby, the UE 100 can execute the measurement on adjacent cells according to the measurement relaxation method.

[0042] The communication unit 120 may receive a radio resource management (RRC) message including a stationary threshold from the serving cell. Thereby, the network can control the measurement according to the measurement relaxation method.

[0043] The communication unit 120 may further receive a low mobility threshold applied to a low mobility criterion indicating that the user equipment is in a low mobility state from the serving cell. The stationary threshold may be different from the low mobility threshold.

[0044] Also, the control unit 140 is a criterion used for selecting whether to perform a measurement according to a measurement relaxation method for relaxing the measurement of the radio quality for an adjacent cell, and determines whether a stationary criterion, which is a criterion for determining whether the UE 100 is in a stationary state, is satisfied. When the stationary criterion is satisfied, the communication unit 120 transmits a radio resource management (RRC) message indicating that the stationary criterion is satisfied to the network. Thereby, the network can know, from the RRC message, that the stationary criterion is satisfied in the UE 100. Thereby, the network can enable the measurement according to the measurement relaxation method based on the fact that the user equipment has satisfied the stationary criterion.

[0045] The RRC message may be a measurement report message for transferring the measurement result of the radio quality to the network. From the measurement report message, the network can know not only that the stationary criterion is satisfied but also the measurement result.

[0046] When the control unit 140 satisfies the condition for joining a stationary event indicating that the stationary criterion is satisfied, the control unit 140 may include a measurement identifier associated with the identifier of the stationary event in the measurement report message. Thereby, the network can know that the condition for joining the stationary event is satisfied based on the measurement identifier.

[0047] The RRC message may be a UE assistance information message used to indicate information of the UE 100 to the network. Thereby, the network can know that the stationary criterion is satisfied by the UE assistance information message.

[0048] The control unit 140 may include state information indicating that the UE 100 is in a stationary state in the UE assistance information message. Thereby, the network can know that the UE 100 is in a stationary state.

[0049] The communication unit 120 may receive setting information from the network for providing the state information to the network. When the control unit 140 has not transmitted the UE assistance information message after receiving the setting information, the control unit 140 may start transmitting the UE assistance information message. Thereby, the network can know the stationary state of the UE 100 by transmitting the setting information to the UE 100.

[0050] When the state information indicating that the UE 100 is not in a stationary state is included in the UE assistance information message last transmitted to the network, the control unit 140 may start transmitting the UE assistance information message in response to the stationary criterion being satisfied. Thereby, the network can know that the stationary criterion is satisfied in the UE 100 that is not in a stationary state.

[0051] The control unit 140 may start a prohibition timer in response to the transmission of the UE assistance information message including the state information. When the prohibition timer is operating, the communication unit 120 does not have to transmit the next UE assistance information message including the state information. Thereby, when the stationary state of the UE 100 frequently switches in a short time, it is not necessary to transmit the RRC message every time it switches, and an increase in signaling can be reduced.

[0052] The control unit 140 is used as a criterion for selecting whether to perform measurements according to a measurement relaxation method that relaxes the measurement of radio quality for adjacent cells, and determines whether a stationary criterion, which is a criterion for determining whether the UE 100 is in a stationary state, is satisfied. The communication unit 120 transmits a radio resource management (RRC) message indicating that the stationary criterion is no longer satisfied to the network in response to the stationary criterion no longer being satisfied. Thereby, the network can know that the stationary criterion is no longer satisfied.

[0053] When the control unit 140 satisfies the detachment condition from a stationary event indicating that the stationary criterion is satisfied, the control unit 140 may include a measurement identifier associated with the identifier of the stationary event in the measurement report message. Thereby, the network can know that the detachment condition from the stationary event is satisfied based on the measurement identifier.

[0054] The control unit 140 may include state information indicating that the UE 100 is not in a stationary state in the UE assistance information message. Thereby, the network can know that the UE 100 is not in a stationary state.

[0055] When the state information indicating that the UE 100 is in a stationary state is included in the UE assistance information message last transmitted to the network, the control unit 140 may start transmitting the UE assistance information message in response to the stationary criterion no longer being satisfied. Thereby, the network can know that the stationary criterion is no longer satisfied in the stationary UE 100.

[0056] The control unit 140 is a criterion used for selecting whether to perform measurements according to a measurement relaxation method that relaxes the measurement of radio quality for adjacent cells, and is a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state, and is a criterion used for selecting whether to perform measurements according to the measurement relaxation method, and is a non-cell-edge criterion that is a criterion for determining whether the UE 100 is in a non-cell-edge state where it is not at the cell edge of the serving cell, and determines whether these are satisfied. The communication unit 120 transmits a radio resource management (RRC) message indicating that both the stationary criterion and the non-cell-edge criterion are satisfied to the network in response to both the stationary criterion and the non-cell-edge criterion being satisfied. Thereby, the network can know that both the stationary criterion and the non-cell-edge criterion are satisfied.

[0057] When the control unit 140 satisfies the joining conditions for a stationary and non-cell-edge event indicating that both the stationary criterion and the non-cell-edge criterion are satisfied, it may include a measurement identifier associated with the identifier of the stationary and non-cell-edge event in the measurement report message. Thereby, the network can know that the joining conditions for the stationary and non-cell-edge events are satisfied based on the measurement identifier.

[0058] The control unit 140 may include state information indicating that the UE 100 is in a stationary state and in a non-cell-edge state in the UE assistance information message. Thereby, the network can know that the UE 100 is in a stationary state and in a non-cell-edge state.

[0059] When the state information indicating that the UE 100 is not in a stationary state or not in a non-cell-edge state is included in the UE assistance information message last transmitted to the network, the control unit 140 may start transmitting the UE assistance information message in response to both the stationary criterion and the non-cell-edge criterion being satisfied. Thereby, the network can know that both the stationary criterion and the non-cell-edge criterion are satisfied in the UE 100 that is not in a stationary state or not in a non-cell-edge state.

[0060] The control unit 140 is a criterion used for selecting whether to perform measurements according to a measurement relaxation method that relaxes the measurement of radio quality for adjacent cells, and is a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state, and a criterion used for selecting whether to perform measurements according to the measurement relaxation method, and is a non-cell-edge criterion that is a criterion for determining whether the UE 100 is in a non-cell-edge state where it is not at the cell edge of the serving cell, and determines whether the criteria are satisfied. The communication unit 120 transmits a radio resource management (RRC) message indicating that at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied to the network in response to at least one of the stationary criterion and the non-cell-edge criterion no longer being satisfied. Thereby, the network can know that at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied.

[0061] When the control unit 140 satisfies the detachment condition from the stationary and non-cell-edge events indicating that both the stationary criterion and the non-cell-edge criterion are satisfied, the control unit 140 may include a measurement identifier associated with the identifier of the stationary and non-cell-edge events in the measurement report message. Thereby, the network can know that the detachment condition from the stationary and non-cell-edge events is satisfied based on the measurement identifier.

[0062] The control unit 140 may include state information indicating that the UE 100 is not in a stationary state or not in a non-cell-edge state in the UE assistance information message. Thereby, the network can know that the UE 100 is not in a stationary state or not in a non-cell-edge state.

[0063] When the UE assistance information message last transmitted to the network includes state information indicating that the UE 100 is in a stationary state and in a non-cell-edge state, the control unit 140 may start transmitting the UE assistance information message in response to at least one of the stationary criterion and the non-cell-edge criterion no longer being satisfied. Thereby, the network can know that at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied in the UE 100 that is in a stationary state and in a non-cell-edge state.

[0064] Note that the operation of a functional unit (specifically, at least one of the communication unit 120 and the control unit 140) included in the UE 100 may be described as the operation of the UE 100.

[0065] (Configuration of the base station) Next, with reference to FIG. 4, the configuration of the base station 200 according to the present embodiment will be described. The base station 200 includes a radio communication unit 220, a network communication unit 230, and a control unit 240.

[0066] The radio communication unit 220 receives a radio signal from the UE 100 and transmits a radio signal to the UE 100, for example. The radio communication unit 220 may include one or more receiving units that receive radio signals and one or more transmitting units that transmit radio signals.

[0067] The network communication unit 230 transmits and receives signals to and from the network. The network communication unit 230 receives a signal from an adjacent base station connected via, for example, the Xn interface, which is an interface between base stations, and transmits a signal to the adjacent base station. Also, the network communication unit 230 receives a signal from a core network device 300 connected via, for example, the NG interface and transmits a signal to the core network device 300.

[0068] The control unit 240 performs various controls in the base station 200. The control unit 240 controls communication with the UE 100 via the radio communication unit 220, for example. Also, the control unit 240 controls communication with nodes (for example, an adjacent base station, a core network device 300) via the network communication unit 230, for example. The operation of the base station 200 described later may be an operation under the control of the control unit 240.

[0069] The control unit 240 may include at least one processor capable of executing a program and a memory for storing the program. The processor may execute the program to perform the operations of the control unit 240. The control unit 240 may include a digital signal processor that performs digital processing of signals transmitted and received via the antenna and the RF circuit. The digital processing includes processing of the RAN protocol stack. Note that the memory stores the program executed by the processor, parameters related to the program, and data related to the program. All or part of the memory may be included in the processor.

[0070] In the base station 200 configured as described above, the control unit 240 is a criterion used for selecting whether to execute measurements according to a measurement relaxation method for relaxing measurements of radio quality with respect to adjacent cells, and is a stationary threshold applied to a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state, and includes the stationary threshold in a radio resource control (RRC) message. The radio communication unit 220 transmits the RRC message to the user equipment. Thereby, the network can control the measurements according to the measurement relaxation method.

[0071] Further, the radio communication unit 220 receives, from the UE 100, a radio resource control (RRC) message that is a criterion used for selecting whether to execute measurements according to a measurement relaxation method for relaxing measurements of radio quality with respect to adjacent cells, and indicates that a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state is satisfied. The control unit 240 controls the measurements of the UE 100 according to the measurement relaxation method. The network can know, from the RRC message, that the stationary criterion is satisfied in the UE 100. Thereby, the network can control the measurements of the UE 100 according to the measurement relaxation method based on the stationary criterion.

[0072] The radio communication unit 220 may transmit the stationary threshold applied to the stationary criterion to the UE 100. Thereby, the network can control the measurements according to the measurement relaxation method based on the stationary criterion.

[0073] The radio communication unit 220 receives, from the UE 100, a radio resource control (RRC) message indicating that a stationary criterion, which is a criterion used for selecting whether to perform measurements according to a measurement relaxation method for relaxing measurements of radio quality for adjacent cells and is a criterion for determining whether the UE 100 is in a stationary state, is no longer satisfied. The control unit 240 controls the measurements of the UE 100 according to the measurement relaxation method. The network can know, from the RRC message, that the stationary criterion is no longer satisfied in the UE 100. Thereby, the network can control the measurements of the UE 100 according to the measurement relaxation method based on the stationary criterion.

[0074] The radio communication unit 220 receives, from the UE 100, a radio resource control (RRC) message indicating that a stationary criterion, which is a criterion used for selecting whether to perform measurements according to a measurement relaxation method for relaxing measurements of radio quality for adjacent cells and is a criterion for determining whether the UE 100 is in a stationary state, and a non-cell-edge criterion, which is a criterion used for selecting whether to perform measurements according to the measurement relaxation method and is a criterion for determining whether the UE 100 is in a non-cell-edge state where it is not at the cell edge of the serving cell, are satisfied. The control unit 240 controls the measurements of the UE 100 according to the measurement relaxation method. Thereby, the network can control the measurements of the UE 100 according to the measurement relaxation method.

[0075] The radio communication unit 220 may transmit to the UE 100 a stationary threshold applied to the stationary criterion and a non-cell-edge threshold applied to the non-cell-edge criterion. Thereby, the network can control the measurements according to the measurement relaxation method based on the stationary criterion and the non-cell-edge criterion.

[0076] The radio communication unit 220 is a criterion used for selecting whether to perform measurements according to a measurement relaxation method that relaxes the measurement of radio quality for adjacent cells, and is a stationary criterion that is a criterion for determining whether the UE 100 is in a stationary state, and a criterion used for selecting whether to perform measurements according to the measurement relaxation method, and is a non-cell-edge criterion that is a criterion for determining whether the UE 100 is in a non-cell-edge state where it is not at the cell edge of the serving cell. The network receives, from the UE 100, an RRC message indicating that at least one of them is no longer satisfied. The control unit 240 controls the measurement of the UE 100 according to the measurement relaxation method. Thereby, the network can control the measurement of the UE 100 according to the measurement relaxation method based on the stationary criterion and the non-cell-edge criterion.

[0077] Note that the operations of the functional units included in the base station 200 (specifically, at least any one of the radio communication unit 220, the network communication unit 230, and the control unit 240) may be described as the operations of the base station 200.

[0078] (System operation) (1) First operation example With reference to FIGS. 5 to 11, a first operation example of the mobile communication system 1 will be described. In the first operation example, a case where the UE 100 transmits a measurement report message to the base station 200 according to whether the stationary criterion is satisfied will be described.

[0079] As shown in FIG. 5, the UE 100 is in the RRC connected state between the UE 100 and the base station 200. Therefore, the UE 100 has established an RRC connection with the cell (serving cell) C managed by the base station 200.

[0080] Hereinafter, the communication between the UE 100 and the base station 200 may be the communication between the UE 100 and the serving cell for the UE 100. Also, the communication (transmission and / or reception) between the UE 100 and the base station 200 may be referred to as the communication (transmission and / or reception) between the UE 100 and the network.

[0081] Step S101: The radio communication unit 220 of the base station 200 transmits the configuration information to the UE 100. The communication unit 120 of the UE 100 receives the configuration information from the base station 200 (serving cell).

[0082] The radio communication unit 220 can transmit a radio resource management (RRC) message including the configuration information to the UE 100. Therefore, the configuration information may be transmitted by broadcast by a system information block (e.g., SIB2, etc.). Also, the configuration information may be individually transmitted to the UE 100 by an RRC reconfiguration message or the like.

[0083] In this operation example, the configuration information includes information for setting a measurement report to the UE 100. The configuration information may include NR report configuration information (ReportConfigNR) that specifies a criterion for triggering a measurement report event. As shown in FIGS. 6 and 7, the NR report configuration information (ReportConfigNR) may include measurement type information (reportType) indicating the type of the measurement report to be set. The measurement type information (reportType) may include relaxed trigger information (relaxedMeasEventTriggered) used for the UE 100 to report that the relaxed measurement condition is satisfied. The relaxed trigger information may include an event identifier (eventId) indicating the trigger criterion for the report. The event identifier (eventId) may indicate a stationary event (eventS1). The event identifier may indicate a stationary and non-cell-edge event (eventS2) described later.

[0084] The event identifier (eventId) may include a stationary threshold value T1 applied to the stationary reference. Therefore, the control unit 240 of the base station 200 can include the stationary threshold value T1 in the RRC message. As a result, the communication unit 120 of the UE100 can receive the stationary threshold value T1 from the serving cell. The stationary threshold value T1 is compared with a power threshold value (s-SearchDeltaP-Stationary) calculated based on the received power measured as the radio quality for the serving cell, and a quality threshold value (s-SearchDeltaQ-Stationary) compared with a value calculated based on the received quality measured as the radio quality for the serving cell, and may include at least one of them. The power threshold value (s-SearchDeltaP-Stationary) is the S SearchDeltaP_stationary may be. S SearchDeltaP_stationary specifies a threshold value for the variation of the received level value (Srxlev) for relaxed measurement. The received level value (Srxlev) may be the received level value for cell selection (Cell selection RX level value). The quality threshold value (s-SearchDeltaQ-Stationary) is the S SearchDeltaQ_stationary may be. S SearchDeltaQ_stationary specifies a threshold value for the variation of the quality value (Squal) for relaxed measurement. The quality value (Squal) may be the quality value for cell selection (Cell selection quality value).

[0085] In addition, the event identifier (eventId) may include period information (t-SearchDeltaP-Stationary) that specifies a predetermined period during which the variation of the received level value (Srxlev) is evaluated. The period information (t-SearchDeltaP-Stationary) may be the T SearchDeltaP_stationary may be. Also, the event identifier (eventId) may include leave report information (reportOnLeave) indicating whether the UE100 should start the measurement reporting procedure when the detachment condition is satisfied for the serving cell.

[0086] The relaxed measurement event triggered information (relaxedMeasEventTriggered) may include reporting interval information (reportInterval) indicating the interval of measurement reports applied to the relaxed measurement event triggered information. Also, the relaxed measurement event triggered information may include reporting amount information (reportAmount) indicating the number of measurement reports applied to the relaxed measurement event triggered information.

[0087] Note that the configuration information may include measurement configuration information (MeasConfig) specifying the measurements to be performed by the UE100. The configuration information may include a measurement object list (MeasObjectToAddMod) related to a list for adding or changing measurement objects. The measurement object list (MeasObjectToAddMod) may include an NR measurement object (MeasObjectNR) specifying information applicable to intra-frequency / inter-frequency measurements of SS (synchronization signal) / PBCH (physical broadcast channel) blocks and / or intra-frequency / inter-frequency measurements of CSI-RS.

[0088] The configuration information may include a measurement identifier list (measIdList / MeasIdToAddModList) related to a list for adding or changing measurement identifiers. The measurement identifier list may include a measurement identifier (measId), a measurement object identifier (measObjectId), and a reporting configuration identifier (ReportConfigId). The measurement identifier (measId), the measurement object identifier (measObjectId), and the reporting configuration identifier (ReportConfigId) are associated with each entry.

[0089] The configuration information may include a reporting configuration list (reportConfigList / ReportConfigToAddModList) related to a list of reporting configurations for adding or changing. The reporting configuration list may include a reporting configuration identifier (reportConfigId) and reporting configuration information (reportConfig). The reporting configuration information (reportConfig) may include NR reporting configuration information (ReportConfigNR).

[0090] The configuration information may include a low-mobility threshold applied to a low-mobility criterion indicating that the UE 100 is in a low-mobility state. Thereby, the UE 100 can receive the low-mobility threshold from the serving cell. The low-mobility threshold may specify a threshold of Srxlev for relaxed measurement, S SearchThresholdP and may be. The low-mobility threshold may specify a threshold of Squal for relaxed measurement, S SearchThresholdQ and may be. The stationary threshold T1 is different from the low-mobility threshold. The minimum setting value of the stationary threshold T1 may be a value lower than the minimum setting value of the low-mobility threshold.

[0091] The control unit 140 of the UE 100 sets the information included in the configuration information. The UE 100 can execute the following operations based on the set information.

[0092] Step S102: The control unit 140 of the UE 100 performs measurement and determination. Specifically, the control unit 140 measures at least one of the received power and the received quality as the radio quality of the serving cell. The received power may be the RSRP (Reference Signal Received Power). The received quality may be the RSRQ (Reference Signal Received Quality). The control unit 140 measures the radio quality by measuring the reference signal (RS) from the serving cell.

[0093] The control unit 140 of the UE 100 determines whether the stationary criterion is satisfied based on the measurement result of the radio quality and the stationary threshold T1. The stationary criterion is a criterion used for selecting whether to execute measurement according to a measurement relaxation method that relaxes the measurement of the radio quality for an adjacent cell, and is a criterion for determining whether the UE 100 is in a stationary state. The control unit 140 may use either the first method or the second method as a method for determining whether the stationary criterion is satisfied.

[0094] In the first method, when the stationary threshold T1 includes the quality threshold, regardless of whether the stationary threshold T1 includes the power threshold, the control unit 140 may determine whether the stationary criterion is satisfied based on the quality threshold. As shown in E1 of FIG. 8, when the stationary threshold T1 includes the quality threshold, that is, when S is set as the quality threshold for the UE100, the control unit 140 may determine whether the following formula is satisfied as the stationary criterion. The control unit 140 applies the set S to the following stationary criterion. SearchDeltaQ_stationary When S is set, the control unit 140 may determine whether the following formula is satisfied as the stationary criterion. SearchDeltaQ_stationary The control unit 140 applies the set S to the following stationary criterion. (Squal Ref - Squal) < S SearchDeltaQ_stationary

[0095] Squal is the current Squal value of the serving cell. Squal Ref is the reference Squal value of the serving cell. The reference Squal value is (i) after the selection or reselection of a new cell, (ii) when (Squal - Squal Ref ) > 0 is satisfied, or (iii) when the stationary criterion has not been satisfied for a predetermined period (T SearchDeltaP_stationary ), the control unit 140 of the UE100 may set the current Squal value of the serving cell to Squal Ref .

[0096] The Squal value is calculated by the following formula. Squal = Q qualmeas - (Q qualmin + Q qualminoffset ) - Qoffset temp

[0097] Q qualmeas is the measured cell quality level (RSRQ). Q qualmin is the minimum required quality level. Q qualminoffset is a predetermined offset that is constantly applied. Qoffset temp is an offset that is temporarily applied.

[0098] Further, when the stationary threshold T1 includes the power threshold but not the quality threshold, the control unit 140 may determine whether the stationary criterion is satisfied based on the power threshold. As shown in E2 of FIG. 8, when the stationary threshold T1 includes the power threshold but not the quality threshold, the control unit 140 may determine whether the following equation is satisfied as the stationary criterion. The control unit 140 applies the set S SearchDeltaP_stationary to the following stationary criterion. (Srxlev Ref - Srxlev) < S SearchDeltaP_stationary

[0099] Srxlev is the current Srxlev value of the serving cell. Srxlev Ref is the reference Srxlev value of the serving cell. The reference Srxlev value is (i) after the selection or reselection of a new cell, (ii) when (Srxlev - Srxlev Ref ) > 0 is satisfied, or (iii) when the stationary criterion has not been satisfied for a predetermined period (T SearchDeltaP_stationary ), the control unit 140 of the UE100 may set the current Srxlev value of the serving cell to Srxlev Ref .

[0100] The Srxlev value is calculated by the following equation.Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset )- P compensation - Qoffset temp

[0101] Q rxlevmeas is the received power (RSRP) of the measured cell. Q rxlevmin is the minimum required received power. Q rxlevminoffset is a predetermined offset that is constantly applied. P compensation is a parameter related to the uplink capability. Qoffset temp is an offset that is temporarily applied.

[0102] In the second method, when the stationary threshold T1 includes the quality threshold and the power threshold, the control unit 140 may determine whether the stationary criterion is satisfied based on the quality threshold and the power threshold. As shown in E3 of FIG. 9, when the stationary threshold T1 includes the quality threshold and the power threshold, that is, when S SearchDeltaQ_stationary is set as the quality threshold for the UE100 and S SearchDeltaP_stationary is set as the power threshold for the UE100, the control unit 140 may determine whether the following formula is satisfied as the stationary criterion. The control unit 140 applies the set S SearchDeltaQ_stationary and S SearchDeltaP_stationary to the following stationary criterion. (Srxlev Ref - Srxlev) < S SearchDeltaP_stationary and (Squal Ref - Squal) < S SearchDeltaQ_stationary

[0103] Also, when the stationary threshold T1 includes the power threshold but does not include the quality threshold, the control unit 140 may determine whether the stationary criterion is satisfied based on the power threshold. As shown in E4 of FIG. 9, when the stationary threshold T1 includes the power threshold but does not include the quality threshold, the control unit 140 may determine whether the following formula is satisfied as the stationary criterion. The control unit 140 applies the set S SearchDeltaP_stationary to the following stationary criterion. (Srxlev Ref - Srxlev) < S SearchDeltaP_stationary

[0104] As shown in A1 of FIG. 10, when the condition S1-1 is satisfied, the control unit 140 may consider that the joining condition for the stationary event is satisfied. The condition S1-1 may be (i) after the UE100 has handed over to the serving cell or (re)established the RRC connection to the serving cell, it has performed normal measurements of the radio quality for the intra-frequency cell, normal measurements of the radio quality for the NR inter-frequency cell, or normal measurements of the radio quality for the inter-RAT cell for at least a predetermined period (T SearchDeltaP_stationary ), and (ii) the stationary criterion has been satisfied for the predetermined period (T SearchDeltaP_stationary ).

[0105] As shown in A2 of FIG. 10, when condition S1-2 is satisfied, the control unit 140 may consider that the condition for leaving the stationary event is satisfied. Condition S1-2 may be that after the joining condition is satisfied, within a predetermined period (T SearchDeltaP_stationary ), the stationary criterion is no longer satisfied.

[0106] As shown in A3 of FIG. 10, with respect to this measurement, the control unit 140 may target the serving cell corresponding to the NR measurement target (MeasObjectNR) associated with the stationary event.

[0107] Also, as shown in B1 of FIG. 11, in the UE 100, for each measurement identifier (measId) included in the measurement identifier list (measIdList) included in the variable measurement setting information (VarMeasConfig), when the corresponding reporting setting information (reportConfig) includes the measurement type information (reportType) set to the relaxed trigger information (relaxedMeasEventTriggered), and when the corresponding measurement target information (measObject) is related to NR, the UE 100 may consider it to be applicable only to the serving cell.

[0108] As shown in B2 of FIG. 11, when the variable measurement report list (VarMeasReportList) does not include a measurement report entry for this measurement identifier, while the measurement type information (reportType) is set to the relaxed trigger information (relaxedMeasEventTriggered) and the condition for joining the event indicated by the event identifier is satisfied, the control unit 140 of the UE 100 may perform the following operations. Note that the variable measurement report list (VarMeasReportList) for each measurement identifier may include the measurement identifier (measId), the cell trigger list (cellsTriggeredList), and the number of reports sent information (numberOfReportsSent).

[0109] The control unit 140 may include a measurement report entry in a variable measurement report list (VarMeasReportList) related to this measurement identifier. The control unit 140 may set the number of reports sent (numberOfReportsSent) defined in the variable measurement report list (VarMeasReportList) related to this measurement identifier to 0. The control unit 140 may include the information of the serving cell in a cell trigger list (cellsTriggeredList) defined in the variable measurement report list (VarMeasReportList) related to this measurement identifier. Also, the control unit 140 may start a measurement report procedure.

[0110] In the following, it is assumed that the control unit 140 determines that the stationary criterion is satisfied, specifically, the condition for joining a stationary event is satisfied, and the description will proceed.

[0111] Step S103: The communication unit 120 of the UE 100 transmits a measurement report message to the serving cell (base station 200, network). The radio communication unit 220 of the base station 200 receives the measurement report message.

[0112] In response to the stationary criterion being satisfied, the communication unit 120 can transmit a measurement report message to the serving cell (network). The measurement report message may indicate that the stationary criterion is satisfied.

[0113] The measurement report message is a radio resource control (RRC) message. The measurement report message may be a message for transferring the measurement result of radio quality to the network. The measurement report message includes measurement result information (MeasResults). The measurement result information (MeasResults) may include a measurement identifier associated with the identifier of the stationary event (event identifier) and the measurement result of the radio quality of the serving cell. The control unit 140 may include the measurement identifier associated with the identifier of the stationary event (event identifier) in the measurement report message when the condition for joining the stationary event indicating that the stationary criterion is satisfied is met.

[0114] Based on the measurement report message, the control unit 240 of the base station 200 may select whether to cause the UE 100 to perform measurements (hereinafter, relaxed measurements) according to a measurement relaxation method for relaxing the measurement of the radio quality for an adjacent cell. In this way, the control unit 240 determines whether to execute the relaxed measurements and controls the relaxed measurements.

[0115] When the control unit 240 selects to cause the UE 100 to perform relaxed measurements, the process of step S104 can be executed. When the measurement report message includes a measurement identifier associated with an identifier of a stationary event (event identifier) and the UE 100 is not performing relaxed measurements (for example, when relaxed measurements are not being caused to be performed on the UE 100), it can be determined that the joining condition for the stationary event is satisfied. Also, the control unit 240 may determine whether the stationary criterion is satisfied based on the measurement results included in the measurement report message. The control unit 240 can determine whether the stationary criterion is satisfied, for example, from the stationary threshold value transmitted to the UE 100 and the measurement results.

[0116] When the joining condition for the stationary event is satisfied, the control unit 240 may determine that the relaxed measurement conditions for causing the UE 100 to perform relaxed measurements are satisfied and select to cause the UE 100 to perform relaxed measurements. When the control unit 240 selects to cause the UE 100 to perform relaxed measurements, the following process can be executed.

[0117] Step S104: The radio communication unit 220 of the base station 200 transmits a relaxed measurement instruction for causing the UE 100 to perform relaxed measurements to the UE 100. The communication unit 120 of the UE 100 receives the relaxed measurement instruction from the serving cell.

[0118] The relaxation measurement instruction may be individually sent to the UE 100 by, for example, an RRC reconfiguration message. The relaxation measurement instruction may include, for example, measurement configuration information (MeasConfig) for causing the UE 100 to perform relaxation measurements. The relaxation measurement instruction may be an instruction for enabling the execution of relaxation measurements. Note that the relaxation measurement instruction may include a parameter for multiplying the tolerance time described later by a predetermined factor.

[0119] Step S105: The control unit 140 of the UE 100 performs relaxation measurements on neighboring cells according to the relaxation measurement instruction. For example, when relaxation measurements are performed, the tolerance time for detecting neighboring cells may be multiplied by a predetermined factor, the tolerance time for measuring neighboring cells may be multiplied by a predetermined factor, or the tolerance time for evaluating neighboring cells may be multiplied by a predetermined factor.

[0120] Note that a neighboring cell is a cell different from the serving cell. The neighboring cell is at least one of an in-band cell, an NR inter-frequency cell, and an inter-RAT frequency cell.

[0121] Step S106: The control unit 140 of the UE 100 performs measurements and determinations in the same manner as in step S102. The control unit 140 may execute the process of step S107 when the departure condition from the stationary event is satisfied. Therefore, the control unit 140 may execute the process of step S107 when the stationary criterion is no longer satisfied.

[0122] The control unit 140 may execute the process of step S107 based on the departure report information (reportOnLeave) included in the event identifier (eventId) indicating the stationary event. The control unit 140 may execute the process of step S107 when the departure report information (reportOnLeave) indicates that the UE 100 should start the measurement reporting procedure when the departure condition is satisfied for the serving cell.

[0123] As shown in B3 of FIG. 11, when the measurement type information (reportType) is set to the relaxed trigger information (relaxedMeasEventTriggered), and the detachment condition from the event indicated by the event identifier is satisfied for the serving cell included in the cell trigger list (cellsTriggeredList) defined in the variable measurement report list (VarMeasReportList) regarding this measurement identifier, the control unit 140 of the UE 100 may perform the following operations.

[0124] The control unit 140 may delete the information of the serving cell defined in the variable measurement report list (VarMeasReportList) regarding this measurement identifier. Also, when the detachment report information (reportOnLeave) is set to "true" in the corresponding report setting, the control unit 140 may start the measurement reporting procedure. Further, when the cell trigger list (cellsTriggeredList) defined in the variable measurement report list (VarMeasReportList) regarding this measurement identifier is empty, the control unit 140 may delete the measurement report entry in the variable measurement report list (VarMeasReportList) regarding this measurement identifier. When the periodic reporting timer for this measurement identifier is running, the reporting timer may be stopped.

[0125] Step S107: The communication unit 120 of the UE 100 transmits a measurement report message to the serving cell (base station 200, network) in the same manner as in step S103. The radio communication unit 220 of the base station 200 receives the measurement report message.

[0126] In response to the stationary reference not being satisfied, the communication unit 120 can transmit a measurement report message to the serving cell (network). The measurement report message may indicate that the stationary reference is no longer satisfied.

[0127] When the control unit 140 satisfies the condition for leaving the stationary event, it may include in the measurement report message the measurement identifier associated with the identifier of the stationary event (event identifier).

[0128] Similar to step S103, the control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurement based on the measurement report message.

[0129] When the control unit 240 selects not to cause the UE 100 to perform relaxed measurement, it can execute the process of step S108. When the measurement report message includes the measurement identifier associated with the identifier of the stationary event (event identifier) and the UE 100 is performing relaxed measurement (for example, when causing the UE 100 to perform relaxed measurement), it can be determined that the condition for leaving the stationary event is satisfied. Also, the control unit 240 may determine whether the stationary criterion is satisfied based on the measurement result included in the measurement report message.

[0130] When the condition for leaving the stationary event is satisfied, the control unit 240 may determine that the relaxed measurement condition for causing the UE 100 to perform relaxed measurement is no longer satisfied and select not to cause the UE 100 to perform relaxed measurement. When the control unit 240 selects not to cause the UE 100 to perform relaxed measurement, it can execute the following process.

[0131] Step S108: The radio communication unit 220 of the base station 200 transmits to the UE 100 a normal measurement instruction for not causing the UE 100 to perform relaxed measurement. The communication unit 120 of the UE 100 receives the normal measurement instruction from the serving cell.

[0132] The normal measurement instruction may be transmitted to the UE 100 individually by an RRC reconfiguration message or the like. The normal measurement instruction may include, for example, measurement configuration information (MeasConfig) for not causing the UE 100 to perform relaxed measurement. The relaxed measurement instruction may be an instruction for invalidating the execution of relaxed measurement.

[0133] The control unit 140 of the UE 100 terminates the execution of the relaxation measurement for the neighboring cell in accordance with the normal measurement instruction. The control unit 140 starts the normal measurement for the neighboring cell.

[0134] (2) Second operation example Referring to FIGS. 12 to 15, the second operation example will be mainly described in terms of differences from the above-described operation example. In the second operation example, a case where the UE 100 transmits a UE assistance information message to the base station 200 according to whether or not a stationary reference is satisfied will be described.

[0135] Step S201: As shown in FIG. 12, the radio communication unit 220 of the base station 200 transmits the setting information to the UE 100 in the same manner as in step S101. The communication unit 120 of the UE 100 receives the setting information from the base station 200 (serving cell).

[0136] In this operation example, as shown in FIG. 13, the setting information may include status setting information (stationaryStatusConfig) for setting the UE 100 to report assistance information to the base station 200 regarding the stationary state detected by the UE 100. The status setting information may include a set value (stationaryStatusProhibitTimer) of a prohibit timer for reporting status information. The prohibit timer (Txxx) starts in response to the transmission of a UE assistance information message including the status information described later. The prohibit timer (Txxx) stops in response to the release of the status setting information (stationaryStatusConfig) or the reception of information for releasing the status setting information (stationaryStatusConfig).

[0137] Also, the setting information may include a stationary threshold T1. The status setting information (stationaryStatusConfig) may include the stationary threshold T1.

[0138] The control unit 140 of the UE 100 sets the information included in the setting information. The UE 100 can execute the following operations based on the set information.

[0139] Step S202: The control unit 140 of the UE 100 performs measurement and determination in the same manner as in step S102. When the stationary criterion is satisfied, the control unit 140 may determine that the UE 100 is in a stationary state. On the other hand, when the stationary criterion is not satisfied, the control unit 140 may determine that the UE 100 is not in a stationary state.

[0140] As shown in FIG. 14, the control unit 140 of the UE 100 having the ability to provide status information (stationary status information) indicating whether it is in a stationary state in the RRC connected state may perform the following operations when it is set to provide the status information and when it enters or exits the stationary state. Note that the UE 100 may be set to provide the status information based on the status setting information.

[0141] When the control unit 140 has not transmitted a UE assistance information message after receiving the status setting information, it may start transmitting a UE assistance information message. Also, when the status information indicating that the UE 100 is not in a stationary state is included in the UE assistance information message last transmitted to the network, the control unit 140 may start transmitting a UE assistance information message in response to the stationary criterion being satisfied. Also, when the status information indicating that the UE 100 is in a stationary state is included in the UE assistance information message last transmitted to the network, the control unit 140 may start transmitting a UE assistance information message in response to the stationary criterion not being satisfied.

[0142] Also, the control unit 140 may start a prohibition timer in response to the transmission of a UE assistance information message including the status information. When the prohibition timer is running, the communication unit 120 does not have to transmit the next UE assistance information message including the status information.

[0143] As shown in FIG. 14, if the control unit 140 has not transmitted a UE assistance information message including status information after being set to provide status information, or if the current stationary state is different from the state indicated by the UE assistance information message including status information that was last transmitted and the prohibition timer is not operating, the control unit 140 may start a prohibition timer with the timer value set to the set value (stationaryStatusProhibitTimer) of the prohibition timer. Further, the control unit 140 may start transmitting a UE assistance information message to provide status information.

[0144] As shown in FIGS. 14 and 15, when the control unit 140 starts transmitting a UE assistance information message to provide status information, the control unit 140 includes the status information in the UE assistance information message. The status information indicates whether the UE 100 is in a stationary state. In this operation example, the status information indicates that the UE 100 is in a stationary state.

[0145] Step S203: The communication unit 120 of the UE 100 transmits a UE assistance information message to the serving cell (base station 200, network). The communication unit 120 can transmit a UE assistance information message to the serving cell (network) in response to the stationary criterion being satisfied. The radio communication unit 220 of the base station 200 receives the UE assistance information message.

[0146] The UE assistance information message is a radio resource control (RRC) message. The UE assistance information message may be a message used to indicate information of the UE 100 to the network. The UE assistance information message may indicate that the stationary criterion is satisfied based on status information indicating whether the UE 100 is in a stationary state.

[0147] The control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurements based on the UE assistance information message. When the control unit 240 selects to cause the UE 100 to perform relaxed measurements, it can execute the process of step S204. When the UE assistance information message includes state information indicating that the UE 100 is in a stationary state, the control unit 240 may select to cause the UE 100 to perform relaxed measurements.

[0148] Steps S204 and S205: They are the same as steps S104 and S105.

[0149] Step S206: The control unit 140 of the UE 100 performs measurements and determinations in the same manner as in step S202. Here, the description will proceed assuming that the control unit 140 no longer satisfies the stationary criterion and determines that the UE 100 is not in a stationary state.

[0150] If the (ii) current stationary state is different from the state indicated by the UE assistance information message that included state information and was last transmitted, and the prohibition timer is not running, the control unit 140 may start transmitting the UE assistance information message. The control unit 140 includes state information indicating that the UE 100 is not in a stationary state in the UE assistance information message.

[0151] Step S207: The communication unit 120 of the UE 100 transmits the UE assistance information message to the serving cell (base station 200, network). The communication unit 120 can transmit the UE assistance information message to the serving cell (network) in response to the stationary criterion no longer being satisfied. The radio communication unit 220 of the base station 200 receives the UE assistance information message.

[0152] The control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurements based on the UE assistance information message. If the control unit 240 selects not to cause the UE 100 to perform relaxed measurements, the process of step S208 can be executed. If the UE assistance information message includes state information indicating that the UE 100 is not in a stationary state, the control unit 240 may select not to cause the UE 100 to perform relaxed measurements.

[0153] Steps S208 and S209: They are the same as steps S108 and S109.

[0154] (3) Third operation example Referring to FIGS. 5 to 7 and FIG. 16, the differences between the third operation example and the above-described operation examples will be mainly described. In the third operation example, stationary and non-cell-edge events (eventS2) will be described. The sequence in this operation example is the same as that in the first operation example.

[0155] The event identifier may indicate stationary and non-cell-edge events (eventS2) described later. As shown in FIG. 6, the event identifier (eventId) may include a stationary threshold T1 applied to the stationary criterion and a non-cell-edge threshold T2 applied to the non-cell-edge criterion.

[0156] The non-cell-edge threshold T2 may include at least one of a power threshold (s-SearchThresholdP) compared with a value calculated based on the received power measured as the radio quality for the serving cell and a quality threshold (s-SearchThresholdQ) compared with a value calculated based on the received quality measured as the radio quality for the serving cell.

[0157] The power threshold (s-SearchThresholdP) may be S SearchThresholdP and the network may be set such that the power threshold (s-SearchThresholdP) is S within SIB2 IntraSearchP and S nonIntraSearchP and the following values. S IntraSearchPSpecifies the Srxlev threshold for in-frequency cell measurement. S nonIntraSearchP Specifies the Srxlev threshold for inter-frequency NR cell measurement and inter-RAT cell measurement. The quality threshold (s-SearchThresholdQ) is S SearchThresholdQ and may be. The network may be configured such that the quality threshold (s-SearchThresholdQ) is within S in SIB2 IntraSearchQ and S nonIntraSearchQ and may be set to the following values. S IntraSearchQ Specifies the Squal threshold for in-frequency cell measurement. S nonIntraSearchQ Specifies the Squal threshold for inter-frequency NR cell measurement and inter-RAT cell measurement.

[0158] Step S102: The control unit 140 of the UE 100 performs measurement and determination. The control unit 140 determines whether the stationary criterion is satisfied based on the measurement result of the radio quality and the stationary threshold T1. In addition, the control unit 140 determines whether the non-cell-edge criterion is satisfied based on the measurement result of the radio quality and the non-cell-edge threshold T2. The non-cell-edge criterion is a criterion used for selecting whether to perform measurement according to a measurement relaxation method that relaxes the measurement of the radio quality for adjacent cells, and is a criterion for determining whether the UE 100 is in a non-cell-edge state that is not at the cell edge of the serving cell. As a method for the control unit 140 to determine whether the non-cell-edge criterion is satisfied, it may be determined whether the following formula is satisfied. Srxlev > S SearchThresholdP and Squal > S SearchThresholdQ

[0159] S SearchThresholdQ If not set, it is not necessary to determine Squal > S SearchThresholdQ That is, the control unit 140 may determine whether Srxlev > S SearchThresholdP is satisfied.

[0160] As shown in B1 of FIG. 16, when condition S2-1 is satisfied, the control unit 140 may consider that the conditions for joining the stationary and non-cell-edge events are satisfied. Condition S2-1 may be that (i) UE100 has executed normal measurement of radio quality for an in-band cell, normal measurement of radio quality for an NR inter-frequency cell, or normal measurement of radio quality for an inter-RAT frequency cell, at least for a predetermined period (T SearchDeltaP_stationary ), (ii) the stationary criterion has been satisfied for a predetermined period (T SearchDeltaP_stationary ), and (iii) the non-cell-edge criterion has been satisfied.

[0161] As shown in B2 of FIG. 16, when condition S2-2 is satisfied, the control unit 140 may consider that the conditions for leaving the stationary and non-cell-edge events are satisfied. Condition S2-2 may be that after the joining conditions are satisfied, (i) the stationary criterion is no longer satisfied for a predetermined period (T SearchDeltaP_stationary ), or (ii) the non-cell-edge criterion is no longer satisfied.

[0162] As shown in B3 of FIG. 16, for this measurement, the control unit 140 may target the serving cell corresponding to the NR measurement object (MeasObjectNR) associated with the stationary and non-cell-edge events.

[0163] Step S103: In response to both the stationary criterion and the non-cell-edge criterion being satisfied, the communication unit 120 can transmit a measurement report message to the serving cell (network).

[0164] The measurement report message includes measurement result information (MeasResults). The measurement result information (MeasResults) may include a measurement identifier associated with an identifier of a stationary and non-cell-edge event (event identifier), and a measurement result of the radio quality of the serving cell. When the joining conditions for the stationary and non-cell-edge events are satisfied, the control unit 140 may include, in the measurement report message, the measurement identifier associated with the identifier of the stationary event (event identifier). The measurement report message may indicate that both the stationary criterion and the non-cell-edge criterion are satisfied by the measurement identifier.

[0165] When the measurement report message includes a measurement identifier associated with an identifier of a stationary and non-cell-edge event (event identifier) and the UE 100 is not performing relaxed measurements (for example, when the UE 100 has not been made to perform relaxed measurements), the control unit 240 of the base station 200 can determine that the joining conditions for the stationary and non-cell-edge events are satisfied. Further, the control unit 240 may determine whether both the stationary criterion and the non-cell-edge criterion are satisfied based on the measurement results included in the measurement report message. The control unit 240 can determine whether both the stationary criterion and the non-cell-edge criterion are satisfied, for example, from the stationary threshold T1 and the non-cell-edge threshold T2 transmitted to the UE 100 and the measurement results.

[0166] When the joining conditions for the stationary and non-cell-edge events are satisfied, the control unit 240 may determine that the relaxed measurement conditions for causing the UE 100 to perform relaxed measurements are satisfied, and select to cause the UE 100 to perform relaxed measurements. When the control unit 240 selects to cause the UE 100 to perform relaxed measurements, the process of step S104 can be executed.

[0167] Step S104: The radio communication unit 220 of the base station 200 transmits a relaxed measurement instruction for causing the UE 100 to perform relaxed measurements to the UE 100. The communication unit 120 of the UE 100 receives the relaxed measurement instruction from the serving cell.

[0168] The relaxation measurement instruction may be, for example, an instruction to make the measurement more relaxed than in the first operation example. The relaxation measurement instruction may have, for example, a higher magnification of the parameter for multiplying the allowable time by a predetermined multiple than in the first operation example. The relaxation measurement instruction may be an instruction to allow non-execution of the measurement for adjacent cells.

[0169] Step S105: The control unit 140 of the UE 100 executes a relaxation measurement for an adjacent cell in accordance with the relaxation measurement instruction.

[0170] Step S106: The control unit 140 of the UE 100 performs measurement and determination in the same manner as in step S102. The control unit 140 may execute the process of step S107 when the conditions for leaving from the stationary and non-cell-edge events are satisfied. Therefore, the control unit 140 may execute the process of step S107 when at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied.

[0171] The control unit 140 may execute the process of step S107 based on the leave report information (reportOnLeave) included in the event identifier (eventId) indicating the stationary and non-cell-edge events. The control unit 140 may execute the process of step S107 when the leave report information (reportOnLeave) indicates that the UE 100 should start the measurement reporting procedure when the leave condition is satisfied for the serving cell.

[0172] Step S107: The communication unit 120 of the UE 100 transmits a measurement report message to the serving cell (base station 200, network) in the same manner as in step S103. The radio communication unit 220 of the base station 200 receives the measurement report message.

[0173] The communication unit 120 can transmit a measurement report message to the serving cell (network) in response to at least one of the stationary criterion and the non-cell-edge criterion no longer being satisfied. The measurement report message may indicate that at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied.

[0174] When the control unit 140 satisfies the detachment conditions for the stationary and non-cell-edge events, it may include in the measurement report message the measurement identifier associated with the identifier of the stationary and non-cell-edge events (event identifier).

[0175] Similar to step S103, the control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurements based on the measurement report message.

[0176] When the control unit 240 selects not to cause the UE 100 to perform relaxed measurements, it can execute the process of step S108. When the measurement report message includes the measurement identifier associated with the identifier of the stationary and non-cell-edge events (event identifier) and the UE 100 is performing relaxed measurements (for example, when causing the UE 100 to perform relaxed measurements), it can be determined that the detachment conditions for the stationary and non-cell-edge events are satisfied. Also, the control unit 240 may determine whether at least one of the stationary criterion and the non-cell-edge criterion is no longer satisfied based on the measurement results included in the measurement report message.

[0177] When the detachment conditions from the stationary event are satisfied, the control unit 240 may determine that the relaxed measurement conditions for causing the UE 100 to perform relaxed measurements are no longer satisfied and select not to cause the UE 100 to perform relaxed measurements. When the control unit 240 selects not to cause the UE 100 to perform relaxed measurements, it can execute the following process.

[0178] Step S108: It is the same as step S108 of the first operation example.

[0179] (4) Fourth operation example Referring to FIGS. 12, 17 to 19, the third operation example will be mainly described in terms of differences from the above-described operation examples. In the fourth operation example, a case will be described in which the UE 100 transmits a UE assistance information message to the base station 200 according to whether both the stationary reference and the non-cell-edge reference are satisfied, or whether the stationary reference and the non-cell-edge reference are satisfied or not. The sequence in this operation example is the same as that in the second operation example.

[0180] Step S201: As shown in FIG. 12, the radio communication unit 220 of the base station 200 transmits setting information to the UE 100 in the same manner as in step S101. The communication unit 120 of the UE 100 receives the setting information from the base station 200 (serving cell).

[0181] In this operation example, as shown in FIG. 13, the setting information may include status setting information (stationaryAndNot-at-cell-edgeStatusConfig) for setting the UE 100 to report assistance information to the base station 200 regarding the stationary state and the non-cell-edge state detected by the UE 100. The status setting information may include a set value (stationaryAndNot-at-cell-edgeStatusProhibitTimer) of a prohibit timer for reporting status information. The prohibit timer (Tyyy) starts in response to the transmission of a UE assistance information message including status information described later. The prohibit timer (Tyyy) stops in response to the release of the status setting information (stationaryAndNot-at-cell-edgeStatusConfig) or the reception of information for releasing the status setting information (stationaryAndNot-at-cell-edgeStatusConfig).

[0182] Further, the setting information may include a stationary threshold T1 and a non-cell-edge threshold T2. The status setting information (stationaryAndNot-at-cell-edgeStatusConfig) may include the stationary threshold T1 and the non-cell-edge threshold T2.

[0183] The control unit 140 of the UE 100 sets the information included in the setting information. Based on the set information, the UE 100 can execute the following operations.

[0184] Step S202: The control unit 140 of the UE 100 performs measurement and determination in the same manner as in step S102. When the stationary criterion is satisfied, the control unit 140 may determine that the UE 100 is in a stationary state. On the other hand, when the stationary criterion is not satisfied, the control unit 140 may determine that the UE 100 is not in a stationary state. Also, when the non-cell-edge criterion is satisfied, the control unit 140 may determine that the UE 100 is in a non-cell-edge state. On the other hand, when the non-cell-edge criterion is not satisfied, the control unit 140 may determine that the UE 100 is not in a non-cell-edge state.

[0185] As shown in FIG. 18, when the control unit 140 of the UE 100 having the ability to provide status information indicating whether it is in a stationary state or not and whether it is in a non-cell-edge state or not in the RRC connected state is set to provide the status information, and when entering or leaving the stationary state, the following operations may be executed. Note that the UE 100 may be set to provide the status information based on the status setting information.

[0186] If the control unit 140 has not transmitted a UE assistance information message after receiving the state setting information, it may start transmitting the UE assistance information message. Further, if the UE assistance information message last transmitted to the network includes state information indicating that the UE 100 is not in a stationary state or not in a non-cell-edge state, the control unit 140 may start transmitting the UE assistance information message in response to both the stationary criterion and the non-cell-edge criterion being satisfied. Also, if the UE assistance information message last transmitted to the network includes state information indicating that the UE 100 is in a stationary state and in a non-cell-edge state, the control unit 140 may start transmitting the UE assistance information message in response to at least one of the stationary criterion and the non-cell-edge criterion no longer being satisfied.

[0187] Further, the control unit 140 may start a prohibition timer in response to transmitting a UE assistance information message including state information. When the prohibition timer is running, the communication unit 120 does not have to transmit the next UE assistance information message including state information.

[0188] As shown in FIG. 18, the control unit 140 may start a prohibition timer with its timer value set to the set value of the prohibition timer (StationaryAndNot-at-cell-edgeStatusProhibitTimer) if (i) it has not transmitted a UE assistance information message including state information since being set to provide state information, or (ii) the current stationary state or non-cell-edge state is different from the state indicated by the UE assistance information message including state information and last transmitted, and the prohibition timer is not running. Also, the control unit 140 may start transmitting a UE assistance information message to provide state information.

[0189] As shown in FIGS. 18 and 19, when the control unit 140 starts transmitting a UE assistance information message to provide status information, the control unit 140 includes the status information in the UE assistance information message. The status information indicates that the UE 100 is in a stationary state and a non-cell-edge state, or that the UE 100 is not in a stationary state or not in a non-cell-edge state. Further, the status information may indicate that the UE 100 has changed from the state of being in a stationary state and a non-cell-edge state, or may indicate that the UE 100 is in at least one of the states of not being in a stationary state and not being in a non-cell-edge state.

[0190] Step S203: The communication unit 120 of the UE 100 transmits a UE assistance information message to the serving cell (base station 200, network). The communication unit 120 can transmit the UE assistance information message to the serving cell (network) in response to both the stationary reference and the non-cell-edge reference being satisfied. The radio communication unit 220 of the base station 200 receives the UE assistance information message.

[0191] The UE assistance information message may indicate, based on the status information, that both the stationary reference and the non-cell-edge reference are satisfied.

[0192] The control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurement based on the UE assistance information message. When the control unit 240 selects to cause the UE 100 to perform relaxed measurement, the process of step S204 can be executed. When the UE assistance information message includes status information indicating that the UE 100 is in a stationary state and a non-cell-edge state, the control unit 240 may select to cause the UE 100 to perform relaxed measurement.

[0193] Steps S204 and S205: They are the same as steps S104 and S105.

[0194] Step S206: Similar to step S202, the control unit 140 of the UE 100 performs measurement and determination. Here, the description will proceed on the assumption that the control unit 140 determines that at least one of the stationary reference and the non-cell edge reference is no longer satisfied.

[0195] If the control unit 140 determines that (ii) the current stationary state or non-cell edge state is different from the state indicated by the UE assistance information message that included the state information and was last transmitted, and the prohibition timer is not running, the control unit 140 may start transmitting the UE assistance information message. The control unit 140 includes in the UE assistance information message state information indicating that the UE 100 is not in the stationary state or not in the non-cell edge state.

[0196] Step S207: The communication unit 120 of the UE 100 transmits the UE assistance information message to the serving cell (base station 200, network). The communication unit 120 can transmit the UE assistance information message to the serving cell (network) in response to at least one of the stationary reference and the non-cell edge reference no longer being satisfied. The radio communication unit 220 of the base station 200 receives the UE assistance information message.

[0197] Based on the UE assistance information message, the control unit 240 of the base station 200 may select whether to cause the UE 100 to perform relaxed measurement. If the control unit 240 selects not to cause the UE 100 to perform relaxed measurement, the process of step S208 can be executed. If the UE assistance information message includes state information indicating that the UE 100 is not in the stationary state or not in the non-cell edge state, the control unit 240 may select not to cause the UE 100 to perform relaxed measurement.

[0198] Steps S208 and S209: This is the same as steps S108 and S109.

[0199] (5) Fifth operation example Referring to FIGS. 20 to 22, the fifth operation example will be mainly described in terms of the differences from the above-described operation examples. In the fifth operation example, UE 100 selects to perform measurements on adjacent cells according to a measurement relaxation method depending on whether a stationary criterion is satisfied.

[0200] Steps S301 and S302: They are the same as steps S101 and S102 or S201 and S202.

[0201] The control unit 140 may determine whether to select to perform relaxed measurements by the following method.

[0202] As shown in FIG. 21, when the setting information (lowMobilityEvaluation) for selecting to perform relaxed measurements based on a low mobility criterion is set in UE 100 and the setting information (cellEdgeEvaluation) for selecting to perform relaxed measurements based on a non-cell-edge criterion is not set in UE 100, and the power threshold (S SearchDeltaP_stationary ) included in the stationary threshold T1 and the period information (T SearchDeltaP_stationary ) are set in UE 100, when the following conditions are satisfied, it may be selected to perform radio quality measurements on in-band cells according to the measurement relaxation method.

[0203] The above conditions may be (i) having performed normal measurements of radio quality on in-band cells, normal measurements of radio quality on NR inter-frequency cells, or normal measurements of radio quality on inter-RAT cells for at least a predetermined period (T SearchDeltaP_stationary ), and (ii) the stationary criterion being satisfied for a predetermined period (T SearchDeltaP_stationary ).

[0204] The control unit 140 determines that for the radio quality of the serving cell, "Srxlev > S nonIntraSearchP " and "Squal > S nonIntraSearchQWhen the condition is satisfied, it may be selected not to perform the radio quality measurement for the inter-frequency cell or the inter-RAT cell for which less than one hour has elapsed since the radio quality measurement. When the relaxed measurement at the high priority frequency is permitted, that is, when highPriorityMeasRelax is set to "true", the control unit 140 may select not to perform the radio quality measurement for the inter-frequency cell or the inter-RAT cell.

[0205] Regarding the radio quality of the serving cell, when the control unit 140 does not satisfy "Srxlev > S" nonIntraSearchP " and "Squal > S" nonIntraSearchQ ", it may be selected to perform the radio quality measurement for the inter-frequency cell or the inter-RAT cell according to the same or different relaxed measurement as the above relaxed measurement.

[0206] Also, as shown in FIG. 22, when both the setting information (lowMobilityEvaluation) for selecting to execute the relaxed measurement based on the low mobility criterion and the setting information (cellEdgeEvaluation) for selecting to execute the relaxed measurement based on the non-cell-edge criterion are set in the UE 100, and the power threshold (S) included in the stationary threshold T1 SearchDeltaP_stationary and the period information (T) SearchDeltaP_stationary are set in the UE 100, when the following conditions are satisfied, it may be selected not to perform the radio quality measurement for the in-frequency cell, the inter-frequency cell, or the inter-RAT cell for which less than one hour has elapsed since the radio quality measurement.

[0207] The above conditions are (i) having performed the normal radio quality measurement for the in-frequency cell, the normal radio quality measurement for the NR inter-frequency cell, or the normal radio quality measurement for the inter-RAT cell for at least a predetermined period (T) SearchDeltaP_stationary , (ii) having satisfied the stationary criterion for a predetermined period (T) SearchDeltaP_stationary , and (iii) having satisfied the non-cell-edge criterion.

[0208] The control unit 140 (i) for at least a predetermined period (T) SearchDeltaP_stationary) Perform normal measurement of radio quality for intra-frequency cells, normal measurement of radio quality for NR inter-frequency cells, or normal measurement of radio quality for inter-RAT cells, and (ii) if the non-cell end criteria are met and (iii) relaxed measurement at a high-priority frequency is not permitted, you may choose to perform measurement of radio quality for low-priority intra-frequency cells, low-priority inter-frequency cells, or low-priority inter-RAT cells according to the same or different relaxed measurements as the above relaxed measurements.

[0209] The control unit 140, for the radio quality of the serving cell, when "Srxlev ≦ S nonIntraSearchP " or "Squal ≦ S nonIntraSearchQ " is satisfied, you may choose to perform measurement of radio quality for high-priority inter-frequency cells or high-priority inter-RAT cells according to the same or different relaxed measurements as the above relaxed measurements.

[0210] Steps S303 and S306: Similar to step S103 or S203, and step S106 or S206. The UE 100 may, for example, after selection and when receiving an instruction from the base station 200, perform the operation selected according to the instruction from the base station 200.

[0211] Steps S304, S305, S307: Similar to step S104 or S204, step S106 or S206, step S104 or S204.

[0212] (Other embodiments) In the above embodiments, the UE 100 may be a specific UE 100B. Since the specific UE 100B is assumed to be stationary compared to the general UE 100A, it is easier to meet the stationary criteria.

[0213] In the above-described embodiment, the UE 100 may perform the above-described operations only when it is in the RRC connected state. Further, for example, when the UE 100 is in the RRC connected state, it may perform any one of the operations of the first to fifth operation examples, and when it is in the RRC idle state or the RRC inactive state, it may also perform the operations of the first to fifth operation examples.

[0214] In the above-described embodiment, the base station 200 may select to cause the UE 100 to perform relaxed measurement according to the conditions described in the fifth operation example, or to not cause the UE 100 to perform measurement on a predetermined neighboring cell (non-execution of measurement). The base station 200 may transmit an instruction based on the selection result to the UE 100. The UE 100 may select to perform relaxed measurement or non-execution of measurement based on the instruction from the base station 200.

[0215] In the above-described embodiment, the UE 100 may use another message (for example, a new RRC message) instead of the measurement report message and the UE assistance information message.

[0216] In the above-described embodiment, the base station 200 may include a plurality of units. The plurality of units may include a first unit that hosts a higher layer included in the protocol stack and a second unit that hosts a lower layer included in the protocol stack. The higher layer may include an RRC layer, an SDAP layer, and a PDCP layer, and the lower layer may include an RLC layer, a MAC layer, and a PHY layer. The first unit may be a CU (Central Unit), and the second unit may be a DU (Distributed Unit). The plurality of units may include a third unit that performs processing lower than the PHY layer. The second unit may perform processing higher than the PHY layer. The third unit may be an RU (Radio Unit). The base station 200 may be one of the plurality of units and may be connected to other units among the plurality of units. Further, the base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

[0217] In the above-described embodiment, the mobile communication system 1 has been described by taking a mobile communication system based on NR as an example. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a system compliant with any TS of LTE or other generation systems (e.g., the sixth generation) of the 3GPP standard. The base station 200 may be an eNB that provides E-UTRA user plane and control plane protocol terminations to the UE 100 in LTE. The mobile communication system 1 may be a system compliant with a TS of a standard other than the 3GPP standard.

[0218] The steps in the operations of the above embodiments do not necessarily have to be executed in chronological order along the order described in the flowchart or sequence diagram. For example, the steps in the operations may be executed in an order different from the order described as the flowchart or sequence diagram, or may be executed in parallel. Also, some of the steps in the operations may be deleted, and additional steps may be added to the process. Furthermore, each of the above operation flows is not limited to being implemented separately and independently, but two or more operation flows can be combined and implemented. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow.

[0219] A program may be provided to cause a computer to execute each process performed by UE100 or base station 200. The program may be recorded on a computer-readable medium. Using a computer-readable medium, it is possible to install a program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, but may be, for example, a recording medium such as a CD-ROM or DVD-ROM. Also, circuits for executing each process performed by UE100 or base station 200 may be integrated, and at least a part of UE100 or base station 200 may be configured as a semiconductor integrated circuit (chipset, SoC).

[0220] In the above embodiments, "transmit" may mean performing processing of at least one layer in the protocol stack used for transmission, or may mean physically transmitting a signal wirelessly or via wire. Alternatively, "transmit" may mean a combination of performing the processing of the at least one layer and physically transmitting a signal wirelessly or via wire. Similarly, "receive" may mean performing processing of at least one layer in the protocol stack used for reception, or may mean physically receiving a signal wirelessly or via wire. Alternatively, "receive" may mean a combination of performing the processing of the at least one layer and physically receiving a signal wirelessly or via wire.

[0221] As described above, the embodiments have been explained in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist.

Description of Reference Numerals

[0222] 1: Mobile communication system 10: Network 120: Communication unit 121: Receiver 122: Transmitter 140: Control unit 200: Base station 220: Wireless communication unit 230: Network communication unit 240: Control unit 300: Core network device

Claims

1. In a radio resource control (RRC) idle state or an RRC inactive state, a receiving unit (121) that receives from a base station (200) first information regarding a stationary criterion, information for designating a period during which fluctuations in a reception level value applied to the stationary criterion are evaluated, second information regarding a non-cell-edge criterion, and third information instructing to execute relaxed measurement when the stationary criterion and the non-cell-edge criterion are satisfied; In the RRC idle state or the RRC inactive state, a control unit (140) that selects to execute the relaxed measurement when the stationary criterion and the non-cell-edge criterion are satisfied based on the third information; and In the RRC idle state or the RRC inactive state, the control unit determines whether the stationary criterion is satisfied during a period in which fluctuations in the reception level value applied to the stationary criterion are evaluated; In an RRC connected state, the receiving unit receives from the base station setting information for setting to provide information indicating whether the device is in a stationary state in the RRC connected state; In the RRC connected state, when the control unit receives the setting information, the control unit starts transmitting a UE assistance information message including information indicating whether the device is in the stationary state in response to a change in the stationary state; A communication device (100).

2. A reception level value threshold applied to the non-cell-edge criterion is included in the second information The communication device according to claim 1.

3. The receiving unit receives from the base station a system information block including the first information, information for designating a period during which fluctuations in the reception level value are evaluated, and the second information The communication device according to claim 1 or 2.

4. The first information indicates a first value as a threshold of the reception level value applied to the stationary criterion, The control unit determines whether the stationary criterion is satisfied based on a reference signal received power (RSRP) of a serving cell and the first value The communication device according to claim 1 or 2.

5. The second information indicates a second value as a threshold of the reception level value applied to the non-cell-edge criterion, The control unit determines whether the non-cell-edge criterion is satisfied based on the second value The communication device according to claim 4.

6. When the control unit further indicates a third value as a threshold value of the reception quality value to which the second information is applied to the non-cell edge reference, in addition to the second value, based on the reference signal reception quality (RSRQ) of the serving cell and the third value, it determines whether the non-cell edge reference is satisfied. The communication device according to claim 5.

7. As the relaxation measurement, the control unit selects at least one of a measurement for an intra-frequency cell and a measurement for an inter-frequency cell. The communication device according to claim 1 or 2.

8. The communication device is a Reduced Capability user equipment. The communication device according to claim 1 or 2.

9. A transmitting unit that transmits to a communication device (100) in an RRC idle state or an RRC inactive state, first information regarding a stationary reference, information for designating a period during which fluctuations in the reception level value applied to the stationary reference are evaluated, second information regarding a non-cell edge reference, and third information for instructing to perform relaxation measurement when the stationary reference and the non-cell edge reference are satisfied; A control unit that controls the communication device in the RRC idle state or the RRC inactive state to select execution of the relaxation measurement when the stationary reference and the non-cell edge reference are satisfied based on the third information; A receiving unit, and Whether the stationary reference is satisfied is determined in a period in which fluctuations in the reception level value applied to the stationary reference are evaluated in the communication device in the RRC idle state or the RRC inactive state. The transmitting unit transmits setting information for setting to provide information indicating whether the communication device is in a stationary state in the RRC connected state to the communication device in the RRC connected state. The receiving unit receives, from the communication device in the RRC connected state, a UE assistance information message including information indicating whether the communication device is in the stationary state transmitted in response to a change in the stationary state when the setting information is transmitted. Base station (200).

10. The threshold value of the reception level value applied to the non-cell edge reference is included in the second information. The base station according to claim 9.

11. The transmitting unit transmits a system information block including the first information, information for specifying a period during which fluctuations in the reception level value are evaluated, and the second information, to the communication device. The base station according to claim 9 or 10.

12. In the communication device, at least one of measurements for an intra-frequency cell and measurements for an inter-frequency cell is performed as the relaxation measurement. The base station according to claim 9 or 10.

13. The communication device is a Reduced Capability user device. The base station according to claim 9 or 10.

14. A communication method executed by a communication device (100), comprising: In an RRC idle state or an RRC inactive state, receiving from a base station (200) first information regarding a stationary criterion, information for specifying a period during which fluctuations in a reception level value applied to the stationary criterion are evaluated, second information regarding a non-cell-edge criterion, and third information instructing to perform a relaxation measurement when the stationary criterion and the non-cell-edge criterion are satisfied; In the RRC idle state or the RRC inactive state, based on the third information, selecting to perform the relaxation measurement when the stationary criterion and the non-cell-edge criterion are satisfied; In an RRC connected state, receiving from the base station setting information for setting to provide information indicating whether the device is in a stationary state in the RRC connected state; In the RRC connected state, when the setting information is received, starting to transmit a UE assistance information message including information indicating whether the device is in a stationary state in response to a change in the stationary state; In the step of selecting to perform the relaxation measurement, determining whether the stationary criterion is satisfied during a period in which fluctuations in the reception level value applied to the stationary criterion are evaluated; Communication method.

15. A communication method executed by a base station (200), comprising: transmitting, to a communication device (100) in a radio resource control (RRC) idle state or an RRC inactive state, first information regarding a stationary reference, information for specifying a period during which fluctuations in a received level value applied to the stationary reference are evaluated, second information regarding a non-cell-edge reference, and third information for instructing to perform relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied controlling, in the RRC idle state or the RRC inactive state, the communication device to select to perform the relaxed measurement when the stationary reference and the non-cell-edge reference are satisfied, based on the third information transmitting, to the communication device in the RRC connected state, setting information for setting to provide information indicating whether the communication device is in a stationary state in the RRC connected state receiving, from the communication device in the RRC connected state, a UE assistance information message including information indicating whether the communication device is in the stationary state, which is transmitted in response to a change in the stationary state when the setting information is transmitted Whether the stationary reference is satisfied is determined in a period in which fluctuations in a received level value applied to the stationary reference are evaluated, in the communication device in the RRC idle state or the RRC inactive state A communication method

Images