JP2014017744A - Communication system, base station device, mobile station device, measurement method, and integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system, a base station device, a mobile station device, a measurement method, and an integrated circuit which can efficiently detect a cell having different frequency from another cell to which a mobile station device is connected.SOLUTION: A base station device notifies a mobile station device of measurement settings including first reference signal settings, a threshold, and second reference signal settings. The mobile station device performs measurement and report of the second reference signal if reception power or reception quality of the first reference signal exceeds the threshold. Thus, it is possible to suppress power consumption required for detecting boost cell having different frequency.

Description

  The present invention relates to a communication system, a base station apparatus, a mobile station apparatus, a measurement method, and an integrated circuit, and more particularly to a communication system that measures a received signal based on settings notified from the base station apparatus.

  The evolution of wireless access methods and wireless networks for cellular mobile communications (hereinafter referred to as “Long Term Evolution (LTE)” or “Evolved Universal Terrestrial Radio Access (EUTRA)”) is the third generation partnership project (3rd Generation Partnership Project (3GPP), which is also referred to as LTE-A (LTE-Advanced, or “Advanced EUTRA)”, which further develops LTE and applies a new technology. ) Is also being considered.

  In Advanced EUTRA, a heterogeneous network in which a plurality of small cells (picocells) are arranged in a macrocell and a mobile station apparatus uses nearby picocells, thereby realizing high-efficiency communication with low power consumption. (Heterogeneous Network; HetNet) technology is being studied. For example, in Non-Patent Document 1, a macro cell is used as a cell for maintaining connection (anchor cell), and a small cell arranged at a frequency different from that of the anchor cell is used as a cell for data communication (boost cell). Has been proposed.

  Further, in Advanced EUTRA, in order to reduce or suppress interference with a mobile station apparatus or increase received signal power, inter-cell cooperative (Cooperative Multipoint; CoMP) communication is performed in which adjacent cells perform communication in cooperation with each other. Is being considered. For example, as inter-cell cooperative communication, different weighting signal processing (precoding processing) is applied to a signal in a plurality of cells, and a plurality of base station devices cooperates to transmit the signal to the same mobile station device (Joint Processing; JP, Joint Transmission; also referred to as JT), scheduling method for coordinated mobile station equipment in multiple cells (Coordinated Scheduling; CS), and mobile station using coordinated beam forming in multiple cells A method of transmitting a signal to a device (Coordinated beamforming; CB) or a method of transmitting a signal using a predetermined resource only in one cell and not transmitting a signal in a resource overlapping with the resource in one cell (Blanking, Muting) is being studied. In this inter-cell cooperative communication, it is necessary to grasp the channel state between the mobile station apparatus and a plurality of cells. For this reason, the mobile station apparatus is notified of the setting of a plurality of channel state information reference signals (CSI-RS), and the mobile station apparatus measures the channel state information reference signal, and the measurement result It is considered that the base station apparatus selects and sets a cell to be used for inter-cell cooperative communication.

  In addition, regarding the said cell, each cell may be a cell managed by a different base station apparatus, and may be a cell managed by the same base station apparatus. Moreover, each cell may be comprised by the radio | wireless part (Remote Radio Head; RRH, also called Remote Radio Unit; RRU) controlled by the control part of a base station apparatus main body. The wireless unit may be connected to the base station apparatus main body by a wire such as an optical fiber, or may be connected wirelessly like a relay station apparatus.

RWS-12003, Views on Rel-12 (http://www.3gpp.org/ftp/workshop/2012-06-11_12_RAN_REL12/Docs/RWS-120003.zip)

3GPP TS 36.331, Radio Resource Control (RRC); Protocol specification. V10.5.0 (http://www.3gpp.org/ftp/Specs/html-info/36331.htm)

  As described above, in order for a mobile station apparatus connected to an anchor cell to detect a boost cell at a different frequency, it is necessary to perform an inter-frequency measurement, and a normal synchronization signal is used. In cell detection, since the detection process takes time, the communication efficiency decreases. In addition, when the boost cell is in synchronization with the anchor cell, a reference signal (for example, a channel state information standard) set for each boost cell (or for each mobile station apparatus) for downlink signal demodulation and channel state confirmation The boost cell can be detected by detecting the signal), but it is necessary to frequently perform reference signal detection processing of a plurality of boost cells, and power consumption of the mobile station apparatus becomes a problem.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a communication system, a base station apparatus, and a base station apparatus capable of efficiently detecting a cell having a frequency different from that of a cell to which the mobile station apparatus is connected. To provide a mobile station apparatus, a measurement method, and an integrated circuit.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the communication system of the present application is a communication system in which the base station apparatus notifies the mobile station apparatus of a measurement setting that designates measurement using a reference signal, and the measurement setting includes the first reference signal Including a setting, a threshold value, and a setting of a second reference signal, the base station apparatus notifies the mobile station apparatus of the measurement setting, and the mobile station apparatus receives received power of the first reference signal. Alternatively, when the measurement value of the reception quality exceeds the threshold value, the second reference signal is measured and reported.

  (2) Further, in the communication system of the present application, the first reference signal and the second reference signal are transmitted at the same frequency.

  (3) In the communication system of the present application, the first reference signal is transmitted from one or more cells using the same radio resource.

  (4) In addition, the base station apparatus of the present application is a base station apparatus that notifies the mobile station apparatus of a measurement setting that designates measurement using a reference signal, and the measurement setting includes a first reference signal. , A threshold value, and a setting of a second reference signal to be measured and reported by the mobile station apparatus when the reception power or reception quality measurement value of the first reference signal exceeds the threshold value. And the mobile station apparatus is notified of the measurement settings.

  (5) Further, in the base station apparatus of the present application, downlink data is not transmitted to the mobile station apparatus at the time and frequency at which the first reference signal is transmitted.

  (6) The mobile station apparatus of the present application is a mobile station apparatus that receives a measurement setting designating measurement using a reference signal from the base station apparatus, and the measurement setting includes the setting of the first reference signal and The second reference signal is measured and reported when the measured value of the received power or the reception quality of the first reference signal exceeds the threshold value. It is characterized by that.

  (7) Further, in the mobile station apparatus of the present application, downlink data is not received from the base station apparatus at the time and frequency at which the measurement of the first reference signal is set.

  (8) Further, in the mobile station apparatus of the present application, when the base station apparatus is set to perform communication at a frequency at which the measurement setting is set, the measurement setting is invalidated.

  (9) The measurement method of the present application is a measurement method of a mobile station apparatus that receives a measurement setting that designates measurement using a reference signal from a base station apparatus, and the measurement setting includes the first reference signal Comparing the measured value of the received power or received quality of the first reference signal with the threshold value, including the setting, the threshold value, and the setting of the second reference signal; and And measuring and reporting the second reference signal if exceeded.

  (10) The integrated circuit of the present application is an integrated circuit mounted on a mobile station apparatus that receives a measurement setting that designates measurement using a reference signal from a base station apparatus, and the measurement setting includes: Including a setting of a reference signal, a threshold value, and a setting of a second reference signal, and when a measured value of received power or reception quality of the first reference signal exceeds the threshold value, It includes the function of measuring and reporting.

  According to the present invention, a communication system, a base station apparatus, a mobile station apparatus, a measurement method, and an integrated circuit that can efficiently detect a cell having a frequency different from that of a cell to which the mobile station apparatus is connected are provided. be able to.

It is a block diagram which shows an example of the base station apparatus which concerns on embodiment of this invention. It is a block diagram which shows an example of the mobile station apparatus which concerns on embodiment of this invention. It is a figure which shows the user plane structure of the base station apparatus and mobile station apparatus which concern on embodiment of this invention. It is a figure which shows the control plane structure of the base station apparatus and mobile station apparatus which concern on embodiment of this invention. It is the figure which showed an example of the measurement setting in the 1st Embodiment of this invention. It is the figure which showed an example of the cell structure which concerns on embodiment of this invention. It is a block diagram which shows an example of the measurement part of the mobile station apparatus which concerns on embodiment of this invention. It is the flowchart which showed an example of the measurement setting procedure in the 1st Embodiment and 2nd Embodiment of this invention. It is the figure which showed an example of the measurement setting in the 2nd Embodiment of this invention. It is the sequence chart which showed an example of the conventional RRM measurement setting management procedure. It is the figure which showed an example of the conventional RRM measurement setting.

  Prior to describing each embodiment of the present invention, techniques related to each embodiment of the present invention will be briefly described below.

[Physical channel]
The main physical channels (or physical signals) used in EUTRA and Advanced EUTRA will be described. A channel means a medium used for signal transmission, and a physical channel means a physical medium used for signal transmission. The physical channel may be added in the future in EUTRA and Advanced EUTRA, or the structure and format of the physical channel may be changed or added. It does not affect.

  In EUTRA and Advanced EUTRA, scheduling of physical channels is managed using radio frames. One radio frame is 10 ms, and one radio frame is composed of 10 subframes. Further, one subframe is composed of two slots (that is, one slot is 0.5 ms). Also, resource blocks are used as a minimum scheduling unit in which physical channels are allocated. A resource block is defined by a constant frequency region composed of a set of a plurality of subcarriers (for example, 12 subcarriers) and a region composed of a constant transmission time interval (1 slot) on the frequency axis.

  Synchronization signals (Synchronization Signals) are composed of three types of primary synchronization signals and secondary synchronization signals composed of 31 types of codes arranged alternately in the frequency domain. Depending on the combination, 504 cell identifiers (Physical Cell Identity (PCI)) for identifying the base station apparatus and frame timing for radio synchronization are shown. The mobile station device specifies the cell ID of the synchronization signal received by the cell search.

  A physical broadcast information channel (Physical Broadcast Channel; PBCH) is transmitted for the purpose of notifying control parameters (broadcast information and system information) commonly used by mobile station apparatuses in a cell. Broadcast information that is not notified on the physical broadcast information channel is transmitted as a layer 3 message (system information) on the physical downlink shared channel after the radio resource is notified on the physical downlink control channel. As broadcast information, a cell global identifier (Cell Global Identifier; CGI) indicating a cell-specific identifier, a tracking area identifier (Tracking Area Identifier; TAI) for managing a standby area by paging, random access setting information (such as a transmission timing timer), Common radio resource setting information and the like are notified.

  The downlink reference signal is classified into a plurality of types according to its use. For example, a cell-specific reference signal (CRS) is a pilot signal transmitted at a predetermined power for each cell, and is downlinked periodically in the frequency domain and the time domain based on a predetermined rule. Link reference signal. The mobile station apparatus measures the reception quality for each cell by receiving the cell-specific reference signal. The mobile station apparatus also uses the downlink cell specific reference signal as a reference signal for demodulating the physical downlink control channel or the physical downlink shared channel transmitted simultaneously with the cell specific reference signal. The sequence used for the cell-specific reference signal is a sequence that can be identified for each cell.

  The downlink reference signal is also used for estimating downlink propagation path fluctuations. A downlink reference signal used for estimating propagation path fluctuation is referred to as a channel state information reference signal (CSI-RS) or a CSI reference signal. Also, the downlink reference signal set individually for each mobile station device is called UE specific Reference Signals (URS) or Dedicated RS (DRS), and is used for demodulation of a physical downlink control channel or a physical downlink shared channel. Used.

  A physical downlink control channel (Physical Downlink Control Channel; PDCCH) is transmitted in some OFDM symbols from the beginning of each subframe, radio resource allocation information according to the scheduling of the base station device to the mobile station device, It is used for the purpose of instructing the adjustment amount of increase / decrease of transmission power. The mobile station apparatus monitors (monitors) a physical downlink control channel addressed to itself before transmitting / receiving a layer 3 message (paging, handover command, etc.) that is downlink data or downlink control data, and By receiving the physical downlink control channel, it is necessary to acquire radio resource allocation information called an uplink grant at the time of transmission and a downlink grant (downlink assignment) at the time of reception from the physical downlink control channel. The physical downlink control channel is configured to be transmitted in the area of the resource block that is individually assigned to the mobile station apparatus from the base station apparatus in addition to the above-described ODFM symbol. Is also possible.

  The Physical Uplink Control Channel (PUCCH) is a data acknowledgment (Acknowledgement / Negative Acknowledgement; ACK / NACK) and downlink propagation path information (channel state information) transmitted on the physical downlink shared channel. ) And a scheduling request (SR) that is an uplink radio resource allocation request (radio resource request). The channel state information (CSI) includes a CQI (Channel Quality Indicator), a PMI (Precoding Matrix Indicator), a PTI (Precoding Type Indicator), and an RI (Rank Indicator). Each indicator may be expressed as “Indication”, but its use and meaning are the same.

  In addition to downlink data, the Physical Downlink Shared Channel (PDSCH) is also used to notify the mobile station apparatus of broadcast information (system information) not notified by the paging or physical broadcast information channel as a layer 3 message. used. The radio resource allocation information of the physical downlink shared channel is indicated by the physical downlink control channel.

  The physical uplink shared channel (PUSCH) mainly transmits uplink data and uplink control data, and can also include control data such as downlink reception quality and ACK / NACK. In addition to uplink data, it is also used to notify the base station apparatus of uplink control information as a layer 3 message. Similarly to the case of the downlink, the radio resource allocation information of the physical uplink shared channel is indicated by the physical downlink control channel.

  An uplink reference signal (also referred to as an uplink pilot signal or an uplink pilot channel) is used by the base station apparatus to demodulate the physical uplink control channel PUCCH and / or the physical uplink shared channel PUSCH. A demodulation reference signal (DMRS) to be used and a sounding reference signal (SRS) mainly used by the base station apparatus to estimate an uplink channel state are included. The sounding reference signal includes a periodic sounding reference signal (Periodic SRS) and an aperiodic sounding reference signal (Aperiodic SRS).

  A physical random access channel (PRACH) is a channel used for notifying a preamble sequence and has a guard time. The preamble sequence is configured so as to express 6-bit information by preparing 64 types of sequences. The physical random access channel is used as a means for accessing the base station apparatus of the mobile station apparatus. The mobile station apparatus transmits a radio resource request when a physical uplink control channel is not set, and transmission timing adjustment information (Timing Advance (TA)) necessary to match the uplink transmission timing with the reception timing window of the base station apparatus. The physical random access channel is used to request the base station apparatus.

  Specifically, the mobile station apparatus transmits a preamble sequence using the radio resource for the physical random access channel set by the base station apparatus. The mobile station apparatus that has received the transmission timing adjustment information sets a transmission timing timer that measures the effective time of the transmission timing adjustment information that is commonly set by the broadcast information (or set individually by the layer 3 message), The uplink state is managed while the transmission timing timer is valid (during time measurement) during the transmission timing adjustment state, and outside the valid period (during stop), the transmission timing is not adjusted (transmission timing is not adjusted). The layer 3 message is a control-plane message exchanged between the mobile station apparatus and the RRC (radio resource control) layer of the base station apparatus, and is used in the same meaning as the RRC signaling or RRC message. Since other physical channels are not related to each embodiment of the present invention, detailed description thereof is omitted.

[Measurement]
FIG. 10 is a sequence chart for explaining a radio resource management (RRM) measurement setting management method for the mobile station apparatus 2 and the base station apparatus 1 in EUTRA.

  In the example of FIG. 10, it is assumed that the base station apparatus 1 can use two different frequencies, F1 and F2, as frequencies operated by the own station, and the mobile station apparatus 2 and the base station apparatus 1 are wirelessly connected at the frequency F1. Is established (radio resource control connected state (Radio Resource Control Connected: RRC_Connected)). Here, the base station apparatus 1 causes the mobile station apparatus 2 to include a message including measurement settings (hereinafter, measurement settings) in order to cause the mobile station apparatus 2 to measure the reception quality of the cell in communication (located cell) and other cells (neighboring cells). Message) (step S101). The measurement setting message includes at least one measurement setting information for each frequency (frequency F1 and frequency F2) to be measured. The measurement setting information includes a measurement ID, a measurement object, a measurement object ID corresponding to the measurement object, a report setting including a measurement event, and a report setting ID corresponding to the report setting. A plurality of report setting IDs may be linked to one measurement target ID. Similarly, one report setting ID may be linked to a plurality of measurement target IDs.

  For example, a case where two measurement objects (frequency F1 and frequency F2) and three report settings are notified and three measurement IDs are set for the combination of the measurement object and the report settings will be described with reference to FIG. To do.

  The base station apparatus 1 assigns identifiers 0 and 1 as measurement object IDs to the frequency F1 and the frequency F2 as measurement objects, and notifies the mobile station apparatus 2 of them. Further, the base station apparatus 1 assigns identifiers 0, 1, and 2 as report setting IDs to report setting 1, report setting 2, and report setting 3, respectively, and notifies the mobile station apparatus 2 of the report settings. Furthermore, the base station apparatus 1 notifies the mobile station apparatus 2 of a measurement ID linked (linked) to the combination of the measurement target identifier and the report setting identifier.

  In FIG. 11, the combination of the measurement target (frequency F1) with identifier 0 and the report setting with identifier 0 is designated as measurement ID # 0. Similarly, the combination of the measurement target of identifier 0 (frequency F1) and the report setting of identifier 1 is designated as measurement ID # 1, and the combination of measurement target of identifier 1 (frequency F2) and the report setting of identifier 2 is measured. It is specified as ID # 2.

  Also, the measurement event information is, for example, when the reception quality of the cell-specific reference signal of the serving cell is below / above a predetermined threshold, the reception quality of the cell-specific reference signal of the neighboring cell is higher than that of the serving cell. It is information composed of a measurement event indicating a condition such as when the reception quality of a neighboring cell exceeds a predetermined threshold when it falls below, and a parameter used to determine the condition. Information such as a threshold value, an offset value, and a time required for establishment of a measurement event is set in the parameter. Non-Patent Document 2 defines, for example, that measurement event A1 is reported when the reception quality of a serving cell (cell in which mobile station apparatus 2 communicates with base station apparatus 1) is better than a threshold. Yes. Further, as measurement event A3, it is defined that reporting is performed when the reception quality of the neighboring cell becomes better than the reception quality of the serving cell plus the offset value. Moreover, it is defined as measurement event A4 to report when the reception quality of an adjacent cell becomes better than a threshold value.

  In step S102, the mobile station apparatus 2 stores the measurement setting information set from the base station apparatus 1 as internal information, and starts the measurement process. Specifically, as described above, the mobile station apparatus 2 manages the measurement ID, the measurement target ID, and the report setting ID in association with each other so as to be linked together, and performs measurement based on the measurement information corresponding to each ID. To start. If these three IDs are linked to one, it is considered valid and the associated measurement is started. If these three IDs are not linked to one (one of the IDs is not set) ), The relevant measurement is not started as invalid. If the measurement setting information can be set without error, the mobile station apparatus 2 transmits a message indicating the completion of measurement setting (measurement setting completion message) to the base station apparatus 1 in step S103.

  When any of the set measurement events satisfies the condition according to the parameter, the mobile station device 2 transmits a measurement report message to the base station device 1 assuming that the measurement event is triggered. (Step S104). In the measurement report message, at least the measurement ID linked to the report setting ID of the triggered measurement event and, if necessary, the measurement result of the associated cell are set and reported. Since the base station apparatus 1 knows to which measurement event report setting ID the measurement ID is linked, the mobile station apparatus 2 does not need to notify the report setting ID in the measurement report message.

  In consideration of the above matters, preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the embodiment of the present invention, when it is determined that a specific description of known functions and configurations related to the embodiment of the present invention obscures the gist of the embodiment of the present invention. Detailed description thereof will be omitted.

[First Embodiment]
A first embodiment of the present invention will be described below.

  FIG. 1 is a block diagram illustrating an example of a base station apparatus 1 according to an embodiment of the present invention. The base station apparatus 1 includes a reception unit 101, a demodulation unit 102, a decoding unit 103, a control unit 104, a coding unit 105, a modulation unit 106, a transmission unit 107, a network signal transmission / reception unit 108, and an upper layer 109.

  Upper layer 109 outputs downlink traffic data and downlink control data to encoding section 105. The encoding unit 105 encodes each input data and outputs the encoded data to the modulation unit 106. The modulation unit 106 modulates the signal input from the coding unit 105. Further, the signal modulated in the modulation unit 106 is multiplexed with a downlink reference signal and mapped as a frequency domain signal. The transmission unit 107 converts the signal input from the modulation unit 106 into a time domain signal, places the converted signal on a carrier wave of a predetermined frequency, and performs power amplification and transmission. A downlink data channel in which downlink control data is arranged typically forms a layer 3 message (RRC (Radio Resource Control) message).

  In addition, the reception unit 101 converts a reception signal from the mobile station apparatus 2 (see FIG. 2) into a baseband digital signal. The digital signal converted by the reception unit 101 is input to the demodulation unit 102 and demodulated. The signal demodulated by the demodulator 102 is then input to the decoder 103 and decoded. Decoding section 103 appropriately separates the received signal into uplink traffic data and uplink control data, and outputs the separated signals to higher layer 109, respectively.

  Base station apparatus control information necessary for controlling each of these blocks is input from the upper layer 109 to the control unit 104, and from the control unit 104, base station apparatus control information related to transmission is transmitted as transmission control information. The base station apparatus control information related to reception is appropriately input to each block of the reception unit 101, demodulation unit 102, and decoding unit 103 as reception control information in each block of the modulation unit 106 and transmission unit 107.

  On the other hand, the network signal transmission / reception unit 108 transmits or receives a control message between a plurality of base station apparatuses 1 (or control station apparatus (MME), gateway apparatus (Gateway), MCE) and the base station apparatus 1. . Control messages are transmitted and received via a network line. Control messages are exchanged on logical interfaces called S1 interface, X2 interface, M1 interface, and M2 interface. In FIG. 1, the other components of the base station apparatus 1 are not related to the present embodiment, and are omitted.

  FIG. 2 is a block diagram showing an example of the mobile station apparatus 2 according to the embodiment of the present invention. The mobile station apparatus 2 includes a reception unit 201, a demodulation unit 202, a decoding unit 203, a measurement unit 204, a control unit 205, a random access processing unit 206, a coding unit 207, a modulation unit 208, a transmission unit 209, and an upper layer 210. Is done.

  Prior to reception, upper layer 210 outputs mobile station apparatus control information to control section 205. The control unit 205 appropriately outputs the mobile station apparatus control information related to reception to the reception unit 201, the demodulation unit 202, the decoding unit 203, and the measurement unit 204 as reception control information. The reception control information includes information such as demodulation information, decoding information, reception frequency band information, reception timing for each channel, multiplexing method, and radio resource arrangement information as reception schedule information.

  The receiving unit 201 receives a signal from the base station apparatus 1 to be described later through one or more receivers (not shown) in the frequency band notified by the reception control information, and converts the received signal into a baseband digital signal. To the demodulator 202. In addition, the reception unit 201 outputs the received reference signal to the measurement unit 204. Demodulation section 202 demodulates the received signal and outputs it to decoding section 203. The decoding unit 203 correctly decodes the demodulated signal based on the reception control information, appropriately separates it into downlink traffic data and downlink control data, and outputs them to the upper layer 210, respectively. The measurement unit 204 measures RSRP, RSRQ, CSI, and the like of the received reference signal and outputs the measurement result to the upper layer 210.

  Prior to transmission, upper layer 210 outputs mobile station apparatus control information to control section 205. The control unit 205 appropriately outputs the mobile station apparatus control information related to transmission to the random access processing unit 206, the encoding unit 207, the modulation unit 208, and the transmission unit 209 as transmission control information. The transmission control information includes information such as encoding information, modulation information, transmission frequency band information, transmission timing for each channel, multiplexing method, and radio resource arrangement information as uplink scheduling information of the transmission signal.

  The upper layer 210 appropriately outputs the uplink traffic data and the uplink control data to the encoding unit 207 according to the uplink channel. The encoding unit 207 appropriately encodes each data according to the transmission control information and outputs the data to the modulation unit 208. The modulation unit 208 modulates the signal encoded by the encoding unit 207. Also, the modulation unit 208 multiplexes the uplink reference signal with the modulated signal and maps it to the frequency band.

  The transmission unit 209 converts the frequency band signal output from the modulation unit 208 into a time domain signal, places the converted signal on a carrier wave of a predetermined frequency, performs power amplification, and one or more transmitters (not shown) Send from.

  In FIG. 2, the other components of the mobile station apparatus 2 are omitted because they are not related to this embodiment.

  Next, the structure of the radio interface protocol between the base station apparatus and the mobile station apparatus is shown. FIG. 3 is a block diagram illustrating a radio protocol architecture of a user plane (U-plane). FIG. 4 is a block diagram showing a radio protocol structure of a control plane (C-plane). The user plane is a protocol stack for transmitting / receiving user data, and the control plane is a protocol stack for transmitting / receiving control signals.

  3 and 4, in the physical layer (PHY) which is the first layer (layer 1), the above-described physical channel is used between different physical layers, that is, between the physical layers on the transmission side and the reception side. Communication takes place. The physical layer is connected to an upper medium access control (MAC) layer via a transport channel, and the physical layer transmits an information transfer service to the MAC layer via the transport channel. (Information transfer service).

  In the MAC layer of the second layer (layer 2), mapping between logical channels and transport channels, error correction by HARQ (Hybrid Automatic Repeat reQuest), transfer processing based on priority between logical channels, etc. It is carried out. The MAC layer is connected to a radio link control (RLC) layer, which is an upper layer, via a logical channel.

  The second layer RLC layer supports data transfer reliability. In the RLC layer, there are three types of operation modes, namely, a transparent mode (TM), a non-acknowledged mode (UM), and an acknowledged mode (AM) depending on the data transmission method. In AM, error correction by ARQ, protocol error detection, and the like are performed.

  A PDCP (Packet Data Convergence Protocol) layer in the second layer performs header compression to reduce the IP packet header size, data encryption, and decryption.

  The radio resource control (RRC) layer of the third hierarchy (layer 3) is defined only in the control plane. The RRC layer broadcasts NAS (non-access stratum) and AS (access stratum) related information, manages RRC connection (Establishment / maintenance / release), configures radio bearer (RB) (configuration), Configuration (re-configuration) and release (release), mobility (handover), measurement management and reporting, QoS management, and the like.

  The NAS layer located above the RRC layer performs session management, mobility management, and the like.

  Here, the MAC layer and the RRC layer of the base station device 1 exist as part of the upper layer 109. The MAC layer of the mobile station apparatus 2 exists as part of the random access processing unit 206 and the upper layer 209, and the RRC layer of the mobile station apparatus 2 exists as part of the measurement unit 204 and the upper layer 209.

  Next, measurement settings (Measurement Configuration) in the present embodiment will be described with reference to FIG.

  In the present embodiment, the measurement setting is similar to the above-described conventional RRM measurement setting, the measurement ID, the measurement object (measurement object), the measurement object ID corresponding to the measurement object, and the report setting including the measurement event, It consists of a report setting ID corresponding to the report setting. Furthermore, in this embodiment, it defines so that the setting of a channel state information reference signal can be included in the setting of a measuring object. The setting of the channel state information reference signal preferably includes at least information on the frequency and time at which the reference signal is transmitted and information on the signal sequence of the reference signal.

  For example, in FIG. 5, two measurement objects are defined. Further, the measurement setting includes two report settings, and two measurement IDs are set for the combination of the measurement object and the report setting.

  In FIG. 5, the combination of the measurement target (frequency F1) with identifier 0 and report setting 1 with identifier 0 is designated as measurement ID # 0. Similarly, the combination of the measurement target of identifier 1 (frequency F2, first channel state information reference signal setting, second channel state information reference signal setting) and report setting 2 of identifier 1 is designated as measurement ID # 1. Is done. The first channel state information reference signal setting and the second channel state information reference signal setting may include setting of a plurality of channel state information reference signals. In the present embodiment, as an example, the first channel state information reference signal setting includes one channel state information reference signal setting (# 1-1), and the second channel state information reference signal setting includes four channel states. Information reference signal settings (# 2-1, # 2-2, # 2-3, # 2-4) are included. Also, here, a measurement event to be reported when the received power measurement value of the adjacent cell exceeds the received power measurement value of the connected cell is specified as report setting 1, and the first channel state information reference is specified as report setting 2 It is assumed that a measurement event to be reported is specified when the received power measurement value of the signal exceeds the threshold value (Th1) and the received power measurement value of the second channel state information reference signal exceeds the threshold value (Th2).

  Here, FIG. 6 shows an example of a cell configuration in the present embodiment.

  In FIG. 6, it is assumed that there is cell 1 at frequency F1, and cell 2, cell 3, cell 4, and cell 5 whose downlink signal transmission timing is synchronized with cell 1 are at frequency F2. The cell 2 transmits a channel state information reference signal setting (# 1-1) reference signal and a channel state information reference signal setting (# 2-1) reference signal, and the cell 3 transmits a channel state information reference signal. The reference signal for setting (# 1-1) and the reference signal for setting channel state information reference signal (# 2-2) are transmitted, and the reference signal for setting channel state information reference signal (# 1-1) is transmitted from cell 4. And a reference signal for channel state information reference signal setting (# 2-3) is transmitted, and the reference signal for channel state information reference signal setting (# 1-1) and channel state information reference signal setting (# 2) are transmitted from the cell 5. -4) is transmitted. Further, it is assumed that the mobile station apparatus 2 is communicating in the cell 1.

  Next, the measurement unit 204 will be described with reference to FIG.

  The measurement unit 204 includes an RRC layer reference signal measurement unit 71 and a PHY layer reference signal measurement unit 72. The PHY layer reference signal measurement unit 72 measures the RSRP, RSRQ, channel state, and the like of the reference signal input from the reception unit 201 and notifies the RRC layer reference signal measurement unit 71 of the measurement. The RRC layer reference signal measurement unit 71 averages the individual measurement results notified from the PHY layer reference signal measurement unit 72 in the measurement target set by the measurement setting notified from the upper layer 210, if necessary, and reports It is determined whether or not the setting is met, and the measurement result is notified to the upper layer 210. Here, the measurement unit 204 selects a reference signal to be measured based on whether or not the channel setting information reference signal setting is included in the measurement target of the measurement setting notified from the higher layer 210.

  Here, the channel state information reference signal setting may be notified so that a physical parameter (configuration information, etc.) necessary for measurement is included in the setting of the measurement target, and the physical parameter (configuration information, etc.) is PhysicalConfigDedicated or Using the information element of PhysicalConfigDedicatedSCell, a plurality of channel state information reference signal settings may be notified together with identifiable identifiers, and the identifiers may be notified to be included in the measurement target settings. The same notification mechanism can be applied to other embodiments.

  Subsequently, a measurement procedure in the communication system of the present embodiment will be described with reference to FIG.

  In FIG. 8, first, the base station apparatus 1 sets the first channel state information reference signal setting and the second channel state information reference signal setting in the measurement setting information for cell detection at the frequency F2 (step S801). ), The measurement setting including the measurement setting information is notified using the RRC message (step S802).

  The mobile station apparatus 2 notified of the measurement setting information in step S802 stores the notified measurement setting information as internal information, and starts a measurement process based on the measurement setting information (step S803). Specifically, the mobile station apparatus 2 manages and measures the measurement ID, the measurement target identifier, and the report setting identifier in association with each other.

  When there is an identifier of the measurement target linked to the measurement ID and an identifier of the report setting, the measurement is performed with the measurement target linked with the setting regarded as valid, and the measurement target identifier linked to the measurement ID Alternatively, if either or both of the report setting identifiers do not exist, the setting is regarded as invalid and the measurement related to the measurement ID is not performed. When the measurement setting information can be set without error, the mobile station device 2 notifies the base station device 1 of the completion of measurement setting (step S804).

  In step S805, when the report setting is the report setting 2, the PHY layer reference signal measurement unit 72 determines the channel state information reference signal based on the first channel state information reference signal setting included in the measurement target setting. Is reported to the RRC layer reference signal measuring unit 71.

  The RRC layer reference signal measurement unit 71 averages the reported measurement values if necessary, compares the measurement values with a threshold value (Th1), and if the measurement value is greater than or equal to the threshold value (or exceeds the threshold value), The channel state information reference signal is measured based on the channel state information reference signal setting, and it is determined whether or not the condition matches the report setting condition.

  When the measured value of the channel state information reference signal based on the second channel state information reference signal setting satisfies the report setting condition, a measurement report is transmitted using the RRC message to the base station apparatus 1 ( Step S806). The measurement report includes at least a measurement ID, and when the measurement target includes one or more second channel state information reference signal settings, the plurality of second channel state information reference signal settings can be identified. The identifier may be included in the measurement report. In this case, the identifier may be reported to the base station apparatus 1 as a physical cell identifier (physCellId) in order to make a measurement report message common to a conventional message (Measurement Report).

  In step S805, if the report setting is a setting other than the report setting 2 (for example, the report setting used in the conventional RRM measurement, regardless of the presence / absence of the first channel state information reference signal setting, The measurement value of the reference signal set in the second channel state information reference signal setting is compared with the threshold value, or the comparison between the measurement values of the reference signal is also matched with each condition of the report setting. If the condition for report setting is satisfied, the measurement report is transmitted to the base station apparatus 1 using the RRC message as step S806.

  As described above, the mobile station apparatus 2 transmits the first channel state information reference signal that is common to a plurality of cells having the same frequency and the channel state information reference signal that is set for each cell, so that the mobile station apparatus 2 After detecting one channel state information reference signal, measurement of the second channel state information reference signal is performed by measuring a channel state information reference signal (second channel state information reference signal) set for each cell. The measurement for detecting the boost cell at a frequency different from that of the serving cell can be efficiently performed without frequently performing. Further, the transmission interval of the first channel state information reference signal is set longer than the transmission interval of the second channel state information reference signal, or the measurement accuracy required for the measurement of the first channel state information reference signal is increased. By setting it lower than the measurement accuracy required for the measurement of the channel state information reference signal 2, it is possible to suppress power consumption necessary for detecting boost cells at different frequencies.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described. In the first embodiment, an example in which two types of channel state information reference signal settings are included in the measurement target is shown. However, in the present embodiment, an example in which the channel state information reference signal setting is included in the measurement target and the report setting. Show.

  The communication system (base station apparatus 1 and mobile station apparatus 2 (including the measurement unit 204)) used in the description of the present embodiment is the same as that in FIG. 1 and FIG. The explanation will not be repeated.

  Subsequently, measurement settings in the present embodiment will be described with reference to FIG.

  In the present embodiment, the measurement setting is similar to the above-described conventional RRM measurement setting, the measurement ID, the measurement object (measurement object), the measurement object ID corresponding to the measurement object, and the report setting including the measurement event, It consists of a report setting ID corresponding to the report setting. Furthermore, in this embodiment, it defines so that the setting of a channel state information reference signal can be included in the setting of a measurement object, and a report setting. The setting of the channel state information reference signal preferably includes at least information on the frequency and time at which the reference signal is transmitted and information on the signal sequence of the reference signal.

  For example, in FIG. 9, two measurement objects are defined. Further, the measurement setting includes two report settings, and two measurement IDs are set for the combination of the measurement object and the report setting.

  In FIG. 9, a combination of a measurement target (frequency F1) with identifier 0 and report setting 1 with identifier 0 is designated as measurement ID # 0. Similarly, a combination of the measurement target of identifier 1 (frequency F2, channel state information reference signal setting) and report setting 2 of identifier 1 is designated as measurement ID # 1. The channel state information reference signal setting may include setting of a plurality of channel state information reference signals. In this embodiment, it is assumed that four channel state information reference signal settings (# 2-1, # 2-2, # 2-3, # 2-4) are included as an example. Also, here, a measurement event to be reported when the reception power measurement value of the adjacent cell exceeds the reception power measurement value of the connected cell is specified as the report setting 1, and the channels included in the report setting 2 as the report setting 2 The received power measurement value of the reference signal (# 1-1) set in the state information reference signal setting exceeds the threshold value (Th1), and the received power measurement value of the channel state information reference signal set in the measurement target is the threshold value ( A measurement event to be reported when Th2) is exceeded is specified.

  Here, since the configuration of the cell used in the description of the present embodiment is the same as that of the first embodiment (FIG. 6), the description thereof is omitted.

  Subsequently, the measurement procedure in the communication system of the present embodiment will be described with reference to FIG. 8 as in the first embodiment.

  In FIG. 8, first, the base station apparatus 1 sets the channel state information reference signal setting and the threshold value as the measurement setting information and the report setting as the measurement setting information for the cell detection of the frequency F2 (step S801), and the RRC message. Is used to notify the measurement setting including the measurement setting information (step S802).

  The mobile station apparatus 2 notified of the measurement setting information in step S802 stores the notified measurement setting information as internal information, and starts a measurement process based on the measurement setting information (step S803). Specifically, the mobile station apparatus 2 manages and measures the measurement ID, the measurement target identifier, and the report setting identifier in association with each other.

  When there is an identifier of the measurement target linked to the measurement ID and an identifier of the report setting, the measurement is performed with the measurement target linked with the setting regarded as valid, and the measurement target identifier linked to the measurement ID Alternatively, if either or both of the report setting identifiers do not exist, the setting is regarded as invalid and the measurement related to the measurement ID is not performed. When the measurement setting information can be set without error, the mobile station device 2 notifies the base station device 1 of the completion of measurement setting (step S804).

  In step S805, when the report setting is the report setting 2, the PHY layer reference signal measurement unit 72 measures the channel state information reference signal based on the channel state information reference signal setting included in the report setting, Report to the RRC layer reference signal measurement unit 71.

  The RRC layer reference signal measurement unit 71 averages the reported measurement values, if necessary, and compares them with a threshold value (Th1) included in the report setting. When the measurement value exceeds the threshold value, The channel state information reference signal is measured based on the associated channel state information reference signal setting of the measurement target, and it is determined whether or not the condition matches the report setting condition.

  When the measurement value of the channel state information reference signal based on the channel state information reference signal setting of the measurement target satisfies the report setting condition, the measurement report is transmitted to the base station apparatus 1 using the RRC message. (Step S806). The measurement report includes at least a measurement ID, and when the measurement target includes one or more second channel state information reference signal settings, the plurality of second channel state information reference signal settings can be identified. The identifier may be included in the measurement report. In this case, the identifier may be reported to the base station apparatus 1 as a physical cell identifier (physCellId) in order to make a measurement report message common to a conventional message (Measurement Report).

  In step S805, when the report setting is another setting (for example, the report setting used in the conventional RRM measurement, or the measurement value of the reference signal set in the channel state information reference signal setting of the measurement target) And the threshold value comparison or the comparison value between the measured values of the reference signal), if it is determined whether or not it matches the respective conditions of the report setting, and if the condition of the report setting is satisfied, In step S806, a measurement report is transmitted to the base station apparatus 1 using an RRC message.

  As described above, in a plurality of cells having the same frequency, a common channel state information reference signal (# 1-1) and a channel state information reference signal (# 2-1, # 2-2, # 2-3, # 2-4) and the mobile station apparatus 2 detects the channel state information reference signal (# 1-1) included in the report setting, and then is set for each cell. By measuring channel state information reference signals (# 2-1, # 2-2, # 2-3, # 2-4) without frequently measuring channel state information reference signals for each cell, Measurements for detecting a boost cell at a different frequency from the serving cell can be efficiently performed. Also, the transmission interval of the channel state information reference signal included in the report setting is set to be longer than the transmission interval of the channel state information reference signal set as the measurement target, or the channel state information reference signal included in the report setting is measured. Reduces power consumption required to detect boost cells at different frequencies by setting the required measurement accuracy to be lower than the measurement accuracy required for measurement of the channel state information reference signal set as the measurement target. can do.

  Note that the setting of the channel state information reference signal included in the first channel state information reference signal in the first embodiment and the report setting in the second embodiment (that is, the setting of the channel state information reference signal # 1-1). In the above description, the frequency of measurement is reduced to reduce the power consumption of the mobile station apparatus 2 by setting the transmission interval to be long. However, the present invention is not limited to this, and the transmission interval itself is set to be short so that the mobile station apparatus 2 The channel state information reference signal # 1-1 may be partially thinned and measured (that is, the measurement interval may be increased). As a result, it is possible to instruct measurement with radio resources at different times for each mobile station apparatus 2, and it is possible to avoid that all mobile station apparatuses 2 concentrate on a specific time and perform different frequency measurements. .

  In the first embodiment, the example in which the threshold (Th1) used for comparison with the measurement value of the first channel state information reference signal is specified in the report setting has been described. However, the present invention is not limited to this, and the threshold (Th1) ) May be included in the measurement target setting.

  Further, in the above description, when the channel state information reference signal having a frequency different from that of the serving cell is measured, the downlink transmission timing of the channel state information reference signal is the downlink of the serving cell to which the mobile station apparatus 2 is connected. It may be considered that it is synchronized with the link transmission timing, a transmission timing difference may be notified, or synchronization may be performed autonomously by performing synchronization processing using a synchronization channel or a reference signal.

  A plurality of cells in which the downlink transmission timing of the channel state information reference signal having a frequency different from that of the serving cell is synchronized with the downlink transmission timing of the serving cell, and the mobile station apparatus 2 has different downlink transmission timing. When there is a plurality of serving cells, the mobile station apparatus 2 is notified of information indicating the serving cell that is the reference for the transmission timing of the channel state information reference signal of the different frequency notified in the measurement settings. It may be.

  In addition, when the setting of the channel state information reference signal having a frequency different from that of the serving cell is notified as the measurement target and the measurement of the measurement target is valid, the mobile station apparatus 2 transmits the channel state information reference signal The time (subframe unit or frame unit) and frequency may be operated as a section in which the downlink data addressed to the own station is not transmitted in the serving cell (a gap section). At this time, the base station apparatus 1 does not transmit downlink data to the mobile station apparatus 2 at the time (subframe unit or frame unit) and frequency at which the channel state information reference signal is transmitted. This eliminates the need for the mobile station apparatus 2 to simultaneously receive signals having a plurality of frequencies, thereby reducing the circuit scale.

  Further, in the first embodiment, the base station is configured so that the mobile station apparatus 2 performs communication in the cell of the frequency to be measured in a state where the setting of the first channel state information reference signal is notified as the measurement target. When set by the apparatus 1, it may be set not to perform measurement of a measurement target including the setting of the first channel state information reference signal. Alternatively, the measurement target including the setting of the first channel state information reference signal does not include the first channel state information reference signal (that is, only the second channel state information reference signal is set). You may make it operate | move as a thing. As a result, unnecessary measurements when using the boost cell can be stopped without using new signaling. Further, when the mobile station apparatus 2 set by the base station apparatus 1 to perform communication in the cell of the frequency is set not to perform communication in the cell of the frequency, the first channel state information You may make it restart the measurement of the measuring object containing the setting of a reference signal. Thereby, the required measurement can be resumed without using new signaling.

  Similarly, in the second embodiment, the base station apparatus 1 is configured so that the mobile station apparatus 2 performs communication in the cell of the frequency in a state in which the report setting including the setting of the channel state information reference signal is notified. May be set so as not to measure the measurement ID associated with the report setting including the setting of the channel state information reference signal (for example, the measurement ID is deleted). Or the measurement ID may be invalidated). As a result, unnecessary measurements when using the boost cell can be stopped without using new signaling. Further, when the mobile station apparatus 2 set by the base station apparatus 1 to perform communication in the cell of the frequency is set not to perform communication in the cell of the frequency, the channel state information reference signal is set. The measurement ID associated with the report setting including “” may be restarted. Thereby, a required measurement can be restarted without using new signaling.

  As a modification of the first embodiment, first, the base station apparatus 1 sets a measurement setting for comparing the received power of the first channel state information reference signal with a threshold value in the mobile station apparatus 2, and When the mobile station apparatus 2 reports the measurement, the mobile station apparatus 2 may be configured to set a measurement setting for comparing the received power of the second channel state information reference signal with a threshold value. As a result, even in an old mobile station apparatus that does not support a new measurement method, a boost cell at a frequency different from that of the serving cell is detected without frequently measuring the channel state information reference signal for each cell. Can be measured efficiently.

  Further, the measurement value and threshold used in the above description may be Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ). In addition, it may indicate a path loss or other measurement values (SIR, SINR, RSSI, BLER), or may be a combination of a plurality of these measurement values.

  Moreover, although the example used for the detection of the boost cell in the frequency different from a serving cell was shown in the above-mentioned description, it can use also for the detection of not only this but a normal handover destination cell candidate.

  Further, the first channel state information reference signal in the first embodiment may be transmitted at a frequency different from that of the second channel state information reference signal. That is, the mobile station apparatus 2 performs measurement at the frequency at which the first channel state information reference signal is transmitted, and performs measurement at the frequency at which the second channel state information reference signal is transmitted when the threshold value is exceeded. Also good. Similarly, the channel state information reference signal included in the report setting in the second embodiment may be transmitted at a different frequency from the channel state information reference signal included in the measurement target.

  Further, the names of the parameters shown in the embodiment according to the present invention are referred to for convenience of explanation, and even if the parameter names actually applied and the parameter names of the present invention are different, It does not affect the gist of the claimed invention.

  The embodiments according to the present invention have been described above. However, with respect to the base station apparatus and mobile station apparatus according to the present invention, the functions of each part of the base station apparatus and the mobile station apparatus or a part of these functions are realized. The control shown in each embodiment may be performed by recording a program for recording on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” dynamically holds a program for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, it is also assumed that a server that holds a program for a certain time, such as a volatile memory inside a computer system that serves as a server or client. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  Each functional block used in each of the above embodiments may be realized as an LSI that is typically an integrated circuit. Each functional block may be individually formed into chips, or a part or all of them may be integrated into a chip. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology can also be used.

  As mentioned above, although embodiment of this invention has been explained in full detail based on the specific example, it is clear that the meaning of this invention and a claim are not limited to these specific examples. In other words, the description in the present specification is for illustrative purposes and does not limit the present invention.

DESCRIPTION OF SYMBOLS 1 ... Base station apparatus 2 ... Mobile station apparatus 101, 201 ... Reception part 102, 202 ... Demodulation part 103, 203 ... Decoding part 104, 205 ... Control part 105, 207 ... Encoding part 106, 208 ... Modulation part 107, 209 ... Transmission unit 108 ... Network signal transmission / reception unit 109, 210 ... Upper layer 204 ... Measurement unit 206 ... Random access processing unit 71 ... RRC layer reference signal measurement unit 72 ... PHY layer reference signal measurement unit

Claims (10)

A base station device is a communication system that notifies a mobile station device of a measurement setting that specifies measurement using a reference signal,
The measurement settings include a first reference signal setting, a threshold value, and a second reference signal setting,
The base station device notifies the mobile station device of the measurement setting,
The mobile station apparatus measures and reports the second reference signal when a measured value of reception power or reception quality of the first reference signal exceeds the threshold value.   The communication system according to claim 1, wherein the first reference signal and the second reference signal are transmitted at the same frequency.   The communication system according to claim 1, wherein the first reference signal is transmitted from a plurality of cells using the same radio resource. A base station device that notifies a mobile station device of a measurement setting that specifies measurement using a reference signal,
The measurement setting includes a setting of a first reference signal, a threshold value, and a target to be measured and reported by the mobile station apparatus when a measured value of reception power or reception quality of the first reference signal exceeds the threshold value. And setting a second reference signal to be
A base station apparatus that notifies the mobile station apparatus of the measurement setting.   The base station apparatus according to claim 4, wherein downlink data is not transmitted to the mobile station apparatus at a time and frequency at which the first reference signal is transmitted. A mobile station device that receives a measurement setting that specifies measurement using a reference signal from a base station device,
The measurement settings include a first reference signal setting, a threshold value, and a second reference signal setting,
A mobile station apparatus that measures and reports the second reference signal when a measured value of received power or reception quality of the first reference signal exceeds the threshold value.   The mobile station apparatus according to claim 6, wherein downlink data is not received from the base station apparatus at a time and a frequency at which measurement of the first reference signal is set.   The mobile station apparatus according to claim 6, wherein the measurement setting is invalidated when the base station apparatus is set to perform communication at a frequency at which the measurement setting is set. A measurement method of a mobile station apparatus that receives a measurement setting that specifies measurement using a reference signal from a base station apparatus,
The measurement settings include a first reference signal setting, a threshold value, and a second reference signal setting,
Comparing the measured value of received power or received quality of the first reference signal with the threshold;
And a step of measuring and reporting the second reference signal when the measured value exceeds the threshold value. An integrated circuit mounted on a mobile station device that receives a measurement setting that specifies measurement using a reference signal from a base station device,
The measurement settings include a first reference signal setting, a threshold value, and a second reference signal setting,
An integrated circuit comprising a function of measuring and reporting the second reference signal when a measured value of reception power or reception quality of the first reference signal exceeds the threshold value.