JP2019091954A - Terminal device, base station device, communication method, and integrated circuit - Google Patents

Abstract

To provide techniques related to a terminal device, a base station device, a communication method, and an integrated circuit that efficiently continue communication.SOLUTION: A first cell receives a handover command to instruct handover to a second cell from a base station device, performs radio resource control (RRC) reestablishment, assuming radio link failure if a second timer is clocking or expired when a first timer is expired, but does not perform radio resource control (RRC) reestablishment, not assuming radio link failure if the second timer is not clocking or expired when the first timer is expired. The first timer is a timer that starts clocking when the handover command is received. The second timer is a timer that starts clocking when an out-of-sync state in the first cell has been detected a predetermined number of times consecutively, and stops clocking when a sync state in the first cell has been detected the predetermined number of times consecutively.SELECTED DRAWING: Figure 16

Description

  The present invention relates to a terminal device, a base station device, a communication method, and an integrated circuit.

The wireless access method for cellular mobile communications and the wireless network (hereinafter referred to as "Long Term Evolution (LTE: registered trademark)" or "Evolved Universal Terrestrial Radio Access: EUTRA") have a third generation partnership project (3rd Generation).
The Partnership Project (3GPP) is under consideration (Non-Patent Documents 1, 2, 3, 4, 5). In LTE, eNodeB (evolved base station equipment)
Node B) The terminal device is also referred to as UE (User Equipment). LTE is a cellular communication system in which a plurality of areas covered by a base station apparatus are arranged in a cell. A single base station apparatus may manage multiple cells.

  In order to reduce the delay of handover, it is considered that the terminal apparatus (UE: User Equipment) establishes communication with the handover destination base station apparatus while maintaining communication with the connected base station apparatus. (Non-patent document 6).

3GPP TS 36.211 V13.0.0 (2015-12) http: // www. 3 gpp. org / DynaReport / 36843. htm 3GPP TS 36.212 V13.0.0 (2015-12) http: // www. 3 gpp. org / DynaReport / 36843. htm 3GPP TS 36.213 V13.0.0 (2015-12) http: // www. 3 gpp. org / DynaReport / 36843. htm 3GPP TS 36.321 V13.0.0 (2015-12) http: // www. 3 gpp. org / DynaReport / 36843. htm 3GPP TS 36.331 V13.0.0 (2015-12) http: // www. 3 gpp. org / DynaReport / 36843. htm 3GPP TR 36.881 v0.5.0 (2015-11) http: // www. 3 gpp. org / DynaReport / 36843. htm

  The present invention relates to a terminal device capable of efficiently continuing communication with a base station device, a base station device communicating with the terminal device, a communication method used for the terminal device, and a communication method used for the base station device The present invention provides an integrated circuit implemented in the terminal apparatus and an integrated circuit implemented in the base station apparatus.

  (1) In order to achieve the above object, one aspect of the present invention takes the following measures. That is, a first aspect of the present invention is a terminal apparatus that communicates with a base station apparatus via a cell, and in the first cell, a handover command instructing a handover to a second cell is sent from the base station apparatus Radio resource control (RRC) reestablishment is performed as radio link failure when the second timer is clocking or expiration when the first timer expires, and the first timer expires When the second timer is not clocking or expired, it is not considered as radio link failure and does not perform radio resource control (RRC) re-establishment, and the first timer starts clocking when a handover command is received The timer is a timer, and the second timer starts counting when a predetermined number of consecutive out-of-sync conditions in the first cell are detected, and continues synchronization in the first cell. A timer that stops the counter when predetermined count detection Te.

  (2) In the first aspect of the present invention, the second timer further receives a handover command when the handover is a handover that does not continue communication with the first cell after receiving the handover command. After that, the clocking is stopped, and the clocking is continued if the handover is a handover in which communication with the first cell is continued after receiving the handover command.

  (3) In the first aspect of the present invention, when the second timer is a handover in which communication with the first cell is continued even after receiving the handover command, the second timer receives the handover command. Do timekeeping.

  (4) A second aspect of the present invention is a base station apparatus for communicating with a terminal apparatus, which transmits to the terminal apparatus a handover command instructing handover from the first cell to the second cell, Including the value to be set to the first timer, the timer may cause the radio link failure in the first cell if the handover is a handover in which communication with the first cell continues even after receiving the handover command. Used to determine

  (5) A third aspect of the present invention is an integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell, and instructs a handover to a second cell in the first cell. A function of receiving a handover command from the base station apparatus, and radio resource control (RRC) reestablishment as radio link failure when the second timer is counting or expiration when the first timer expires. The terminal device has a function to perform, and a function that does not consider radio link failure and does not perform radio resource control (RRC) re-establishment if the second timer is not counting or is not counting when the first timer has expired. The first timer is a timer that starts counting when a handover command is received, and the second timer continuously loses synchronization in the first cell. It starts timing when constant frequency detecting a timer to stop the counting when the predetermined number of times detected state of synchronization in the first cell in succession.

  (6) A fourth aspect of the present invention is an integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell, and instructs a handover to a second cell in the first cell. Receiving a handover command from the base station device, and considering the radio link failure if the second timer is counting or expiring when the first timer expires, reestablishing radio resource control (RRC) Performing at least a step of not considering radio link failure and not performing radio resource control (RRC) reestablishment if the second timer is not counting or not timing when the first timer expires. Is a timer that starts counting when a handover command is received, and the second timer is a predetermined number of consecutive out-of-sync conditions in the first cell. It starts timing when issuing a timer to stop the counting when the predetermined number of times detected state of synchronization in the first cell in succession.

  According to the present invention, the terminal apparatus and the base station apparatus can efficiently continue communication with each other.

It is a conceptual diagram of the radio | wireless communications system of this embodiment. It is a block diagram which shows an example of schematic structure of the terminal device which concerns on embodiment of this invention. It is a block diagram which shows an example of schematic structure of the base station apparatus which concerns on embodiment of this invention. It is a figure showing the user plane (UP (User-plane, U-Plane)) protocol stack concerning an embodiment of the present invention. FIG. 2 is a diagram illustrating a control plane (CP (Control-plane, C-Plane)) protocol stack according to an embodiment of the present invention. It is a figure which shows an example of the sequence chart regarding the competition based random access procedure which concerns on embodiment of this invention. It is a figure which shows an example of the sequence chart regarding the non-contention based random access procedure concerning embodiment of this invention. It is a figure which shows an example of the sequence chart regarding the hand-over procedure which concerns on embodiment of this invention. It is a figure which shows an example of the sequence chart regarding the radio | wireless resource management measurement setting management method which concerns on embodiment of this invention. It is a figure which shows an example of the radio | wireless resource management measurement setting which concerns on embodiment of this invention. It is a figure which shows the information / parameter contained in RF-Parameters-v1020 which concerns on embodiment of this invention. It is a figure which shows the information / parameter contained in BandParameters-r10 which concerns on embodiment of this invention. It is a figure which shows an example of RF-Parameters-v1020 which concerns on embodiment of this invention. It is a figure which shows the information / parameter contained in RF-Parameters-v1250 which concerns on embodiment of this invention. It is a figure which shows an example of RF-Parameters-rX which concerns on embodiment of this invention. It is a figure which shows an example of the sequence chart regarding the notification of the terminal device capability information which concerns on embodiment of this invention. FIG. 6 shows an example of a flowchart diagram for detecting a Radio Link Failure according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described.

  The wireless communication system of the present embodiment will be described.

FIG. 1 is a conceptual view of a wireless communication system according to the present embodiment. In FIG. 1, the wireless communication system includes a terminal device 2 and a base station device 3. The base station device 3 includes a source base station device 3A, a target base station device 3B, and an MME (Mobility Management Entity) / GW (Gateway). Uu is a radio access link between the terminal device 2 and the base station device 3. Uu includes uplink from the terminal device 2 to the base station device 3 and downlink from the base station device 3 to the terminal device 2. X2 is a backhaul link between the source base station device 3A and the target base station device 3B. S1 is a backhaul link between the source base station device 3A / target base station device 3B and the MME / GW.

  The terminal device 2 may perform handover from the source base station device 3A to the target base station device 3B. The terminal device 2 may perform handover from the source cell to the target cell. The source cell may be managed by the source base station device 3A. The target cell may be managed by the target base station device 3B. The source base station device 3A and the target base station device 3B may be the same device. That is, the terminal device 2 may perform handover from the source cell managed by the source base station device 3A to the target cell managed by the source base station device 3A. The source cell is also referred to as a source primary cell. The target cell is also referred to as a target primary cell.

  Physical channels and physical signals of this embodiment will be described.

In FIG. 1, in uplink radio communication from the terminal device 2 to the base station device 3, the following uplink physical channels are used. The uplink physical channel is used by the physical layer to transmit information output from the upper layer.
-PUCCH (Physical Uplink Control Channel)
-PUSCH (Physical Uplink Shared Channel)
-PRACH (Physical Random Access Channel)

The PUCCH is used to transmit uplink control information (UCI). The uplink control information includes downlink channel state information (CSI), and a scheduling request (Scheduling Request) used to request a PUSCH (Uplink-Shared Channel: UL-SCH) resource for initial transmission. SR), downlink data (Transport blo
ck, Medium Access Control Protocol Data
Unit: MAC PDU, Downlink-Shared Channel: DL-SCH, Physical Downlink Shared Channel (PDSCH). This includes HARQ-ACK (Hybrid Automatic Repeat request acknowledgment). HARQ-ACK indicates ACK (acknowledgement) or NACK (negative-acknowledgement). HARQ-ACK is also referred to as HARQ feedback, HARQ information, HARQ control information, and ACK / NACK.

  The PUSCH is used to transmit uplink data (Uplink-Shared Channel: UL-SCH). The PUSCH may be used to transmit HARQ-ACK and / or channel state information along with uplink data. Also, PUSCH may be used to transmit only channel state information or only HARQ-ACK and channel state information. PUSCH is used to transmit random access message 3.

  The PRACH is used to transmit a random access preamble (random access message 1). The PRACH indicates an initial connection establishment procedure, a handover procedure, a connection re-establishment procedure, synchronization for uplink transmission (timing adjustment), and a request for PUSCH (UL-SCH) resources. Used for

In FIG. 1, in uplink radio communication, the following uplink physical signals are used. The uplink physical signal is not used to transmit information output from the upper layer, but is used by the physical layer.
· Uplink Reference Signal (UL RS)
)

In the present embodiment, the following two types of uplink reference signals are used.
-DMRS (Demodulation Reference Signal)
・ SRS (Sounding Reference Signal)

  DMRS relates to PUSCH or PUCCH transmission. The DMRS is time multiplexed with the PUSCH or PUCCH. The base station apparatus 3 uses DMRS to perform PUSCH or PUCCH channel correction. Hereinafter, transmission of both PUSCH and DMRS is referred to simply as transmission of PUSCH. Hereinafter, transmitting PUCCH and DMRS together is referred to simply as transmitting PUCCH.

  The SRS is not related to PUSCH or PUCCH transmission. The base station apparatus 3 may use SRS for channel state measurement. The SRS is transmitted in the last SC-FDMA symbol in the uplink subframe or in the SC-FDMA symbol in the UpPTS.

In FIG. 1, in downlink radio communication from the base station apparatus 3 to the terminal apparatus 2, the following downlink physical channels are used. The downlink physical channel is used by the physical layer to transmit information output from higher layers.
・ PBCH (Physical Broadcast Channel)
・ PCFICH (Physical Control Format Indicator Channel)
-PHICH (Physical Hybrid automatic repeat request Indicator Channel)
・ PDCCH (Physical Downlink Control Channel)
・ EPDCCH (Enhanced Physical Downlink Control Channel)
-PDSCH (Physical Downlink Shared Channel)-PMCH (Physical Multicast Channel)

The PBCH is used to broadcast a master information block (MIB, Broadcast Channel: BCH) commonly used in the terminal device 2. The MIB is transmitted at an interval of 40 ms, and the MIB is repeatedly transmitted at a period of 10 ms. Specifically, the initial transmission of the MIB is performed in subframe 0 in the radio frame satisfying SFN mod 4 = 0, and the retransmission of the MIB is performed in subframe 0 in all other radio frames. SFN (system frame number) is a radio frame number. MIB is system information. For example, the MIB includes information indicating SFN.

  The PCFICH is used to transmit information indicating an area (OFDM symbol) used for PDCCH transmission.

  The PHICH is used to transmit an HARQ indicator for uplink data (Uplink Shared Channel: UL-SCH) received by the base station device 3. The HARQ indicator indicates HARQ-ACK.

  The PDCCH and the EPDCCH are used to transmit downlink control information (DCI). The downlink control information is also referred to as DCI format. The downlink control information includes downlink grant and uplink grant. A downlink grant is also referred to as downlink assignment or downlink allocation.

  One downlink grant is used for scheduling one PDSCH in one serving cell. The downlink grant is used to schedule the PDSCH in the same subframe as the subframe in which the downlink grant is transmitted.

  One uplink grant is used for scheduling of one PUSCH in one serving cell. The uplink grant is used to schedule the PUSCH in a subframe four or more after the subframe in which the uplink grant is transmitted.

  The uplink grant transmitted on PDCCH includes DCI format 0. The PUSCH transmission scheme corresponding to DCI format 0 is a single antenna port. The terminal device 2 uses a single antenna port transmission scheme for PUSCH transmission corresponding to DCI format 0. PUSCH to which the single antenna port transmission scheme is applied is used for transmission of one codeword (one transport block).

  The uplink grant transmitted on PDCCH includes DCI format 4. The PUSCH transmission scheme corresponding to DCI format 4 is closed loop space multiplexing. The terminal device 2 uses a closed loop space multiplexing transmission scheme for PUSCH transmission corresponding to the DCI format 4. The PUSCH to which the closed loop spatial multiplexing scheme is applied is used for the transmission of up to two codewords (up to two transport blocks).

  The CRC parity bits added to the downlink grant or uplink grant are C-RNTI (Cell-Radio Network Temporary Identifier), Temporary C-RNTI, SPS (Semi Persistent Scheduling) C-RNTI (Cell-Radio Network Temporary) Identifier) is scrambled. C-RNTI and SPS C-RNTI are identifiers for identifying a terminal device in a cell. The Temporary C-RNTI is used in a contention based random access procedure.

  C-RNTI is used to control PDSCH or PUSCH in one subframe. The SPS C-RNTI is used to periodically allocate PDSCH or PUSCH resources. The Temporary C-RNTI is used to schedule retransmission of random access message 3 and transmission of random access message 4.

The PDSCH is used to transmit downlink data (Downlink Shared Channel: DL-SCH). PDSCH is used to transmit random access message 2 (random access response). The PDSCH is used to send a handover command.

The random access response includes a RAR grant (Random Access Response grant). The RAR grant is an uplink grant transmitted on the PDSCH. The terminal device 2 uses a single antenna port transmission scheme for PUSCH transmission corresponding to RAR grant and PUSCH retransmission for the same transport block.

  The PMCH is used to transmit multicast data (Multicast Channel: MCH).

In FIG. 1, the following downlink physical signals are used in downlink radio communication. The downlink physical signal is not used to transmit information output from the upper layer, but is used by the physical layer.
・ Synchronization signal (SS)
・ Downlink Reference Signal (DL)
RS)

  The synchronization signal is used by the terminal device 2 to synchronize the downlink frequency domain and time domain. The synchronization signal includes PSS (Primary Synchronization Signal) and SSS (Second Synchronization Signal).

  The downlink reference signal is used by the terminal device 2 to perform channel correction of the downlink physical channel. The downlink reference signal is used by the terminal device 2 to calculate downlink channel state information.

In the present embodiment, the following seven types of downlink reference signals are used.
・ CRS (Cell-specific Reference Signal)
-URS (UE-specific Reference Signal) related to PDSCH
-DMRS (Demodulation Reference) related to EPDCCH
Signal)
-NZP CSI-RS (Non-Zero Power Chanel State Information-Reference Signal)
-ZP CSI-RS (Zero Power Chanel State Information-Reference Signal)
MBSFN RS (Multimedia Broadcast and Multicast Service over Single Frequency Network Reference Signal)
・ PRS (Positioning Reference Signal)

  The downlink physical channel and the downlink physical signal are collectively referred to as a downlink signal. The uplink physical channel and uplink physical signal are collectively referred to as uplink signal. The downlink physical channel and the uplink physical channel are collectively referred to as a physical channel. Downlink physical signals and uplink physical signals are collectively referred to as physical signals.

BCH, MCH, UL-SCH and DL-SCH are transport channels. A channel used in a medium access control (MAC) layer is called a transport channel. A unit of transport channel used in the MAC layer is also referred to as transport block (TB) or MAC PDU (Protocol Data Unit). In the MAC layer, control of HARQ (Hybrid Automatic Repeat request) is performed for each transport block. Transport block, MA
Layer C is a unit of data delivered to the physical layer. In the physical layer, transport blocks are mapped to codewords, and encoding processing is performed for each codeword.

The base station device 3 and the terminal device 2 exchange (transmit and receive) signals in a higher layer. For example, in the radio resource control (RRC: Radio Resource Control) layer, the base station apparatus 3 and the terminal apparatus 2 transmit and receive RRC signaling (RRC message: Radio Resource Control message, also referred to as RRC information: Radio Resource Control information). You may Also, the base station apparatus 3 and the terminal apparatus 2 may transmit and receive MAC CE (Control Element) in the medium access control (MAC) layer. Here, RRC signaling and / or MAC CE are also referred to as higher layer signaling.

  PUSCH and PDSCH are used to transmit RRC signaling and MAC CE. Here, RRC signaling transmitted on the PDSCH from the base station device 3 may be common signaling to a plurality of terminal devices 2 in a cell. The RRC signaling transmitted on the PDSCH from the base station apparatus 3 may be dedicated signaling (also referred to as dedicated signaling or UE specific signaling) for a certain terminal apparatus 2. The cell specific parameter may be transmitted using common signaling to a plurality of terminal devices 2 in a cell or dedicated signaling to a certain terminal device 2. The UE specific parameters may be transmitted to a certain terminal device 2 using dedicated signaling.

  The wireless network of this embodiment will be described.

  The communicable range (communication area) of each frequency controlled by the base station device 3 is regarded as a cell. At this time, the communication area covered by the base station apparatus 3 may be different in size and shape in each frequency. Also, the area to be covered may be different for each frequency. Furthermore, a wireless network in which cells having different types of base station apparatus 3 and different cell radius sizes are mixed in the same frequency or different frequency areas to form one communication system is a heterogeneous network. It is called.

  The terminal device 2 operates by regarding the inside of the cell as a communication area. When the terminal device 2 moves from one cell to another cell, the cell reselection procedure at the time of non-radio connection (idle state, also referred to as RRC_IDLE state), radio connection (also referred to as connected state, RRC_CONNECTED state) Move to another appropriate cell by the handover procedure. An appropriate cell is a cell that is determined that access of the terminal device 2 is not generally prohibited based on information specified from the base station device 3, and the downlink reception quality is a predetermined condition. Indicate a cell that satisfies

  The base station device 3 manages, for each frequency, cells which are areas in which the terminal device 2 can communicate. One base station apparatus 3 may manage a plurality of cells.

  When the terminal device 2 can communicate with a certain base station device 3, among cells of the base station device 3, a cell set to be used for communication with the terminal device 2 is a serving cell (Serving cell). And other cells not used for communication are referred to as neighboring cells.

  The wireless protocol structure of this embodiment will be described.

  FIG. 4 is a diagram showing a user plane (UP (User-plane, U-Plane)) protocol stack that handles user data of the terminal device 2 and the base station device 3 of the EUTRA radio network (EUTRAN). FIG. 5 is a diagram showing a control plane (CP (Control-plane, C-Plane)) protocol stack that handles control data.

  In FIG. 4 and FIG. 5, a physical layer (Physical layer: PHY layer) provides a transmission service to an upper layer using a physical channel (Physical Channel). The PHY layer is connected to an upper medium access control layer (MAC layer) by a transport channel. Data are moved between the MAC layer, the PHY layer, and layers via transport channels. In the PHY layer of the terminal device 2 and the base station device 3, transmission and reception of data are performed via physical channels.

  The MAC layer maps various logical channels to various transport channels. The MAC layer is connected to the upper Radio Link Control Layer (RLC layer) by a logical channel. Logical channels are roughly divided according to the type of information to be transmitted, and are divided into control channels for transmitting control information and traffic channels for transmitting user information. The MAC layer has a function of controlling the PHY layer to perform intermittent reception / transmission (DRX / DTX), a function of executing a random access procedure, a function of notifying transmission power information, and a function of performing HARQ control.

  The RLC layer segments and concatenates data received from the upper layer, and adjusts the data size so that the lower layer can transmit data appropriately. The RLC layer also has a function to guarantee QoS (Quality of Service) required by each data. That is, the RLC layer has functions such as retransmission control of data.

  A packet data convergence protocol layer (PDC layer) has a header compression function for compressing unnecessary control information in order to efficiently transmit an IP packet which is user data in a wireless section. The PDCP layer also has a data encryption function.

  Furthermore, in the control plane protocol stack, there is a Radio Resource Control layer (RRC layer). The RRC layer performs radio bearer (Radio Bearer: RB) setup / reconfiguration, and controls logical channels, transport channels, and physical channels. The RB is divided into a Signaling Radio Bearer (SRB) and a Data Radio Bearer (DRB), and the SRB is used as a path for transmitting an RRC message, which is control information. The DRB is used as a path for transmitting user data. Each RB is set between the RRC layer of the base station apparatus 3 and the terminal apparatus 2.

Note that the PHY layer is a commonly known open system interconnection (Open System
s In the hierarchical structure of the Interconnection (OSI) model, the MAC layer, the RLC layer and the PDCP layer correspond to the data link layer which is the second layer of the OSI model, and the RRC layer corresponds to the physical layer of the first layer in the hierarchical structure of the OSI model. It corresponds to the network layer which is the third layer of the model.

  Also, the signaling protocol used between the network and the terminal device 2 is divided into an Access Stratum (AS) protocol and a Non-Access Stratum (NAS) protocol. For example, the protocol below the RRC layer is an access layer protocol used between the terminal device 2 and the base station device 3. Further, protocols such as connection management (CM) of the terminal device 2 and mobility management (MM) are non-access layer protocols, and are used between the terminal device 2 and the core network (CN). For example, as shown in FIG. 5, communication using a non-access layer protocol is transparently performed between the terminal device 2 and a mobile management entity (MME) via the base station device 3.

  The radio resource management measurement of this embodiment will be described.

  FIG. 9 is a sequence chart diagram for describing a radio resource management (RRM) measurement setting management method of the terminal device 2 and the base station device 3 in EUTRA.

  In the example of FIG. 9, it is assumed that the base station apparatus 3 can use two different frequencies F1 and F2 as frequencies used by the own station, and the terminal apparatus 2 and the base station apparatus 3 have wireless connection at the frequency F1. It is an established state (Radio Resource Control Connected (RRC_Connected)). Here, the base station device 3 is a message including a measurement setting to make the terminal device 2 measure the reception quality of the cell (the serving cell) in communication and other cells (peripheral cells) (hereinafter, measurement setting message ) Is transmitted (step S91). The measurement setting message includes at least one measurement setting information for each frequency to be measured (frequency F1 and frequency F2). The measurement setting information includes a measurement ID, a measurement object (measurement object), a measurement target 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, the case where two measurement targets (frequency F1 and frequency F2) and three report settings are notified and three measurement IDs are set for the combination of the measurement targets and the report settings will be described using FIG. Do.

  The base station apparatus 3 allocates identifiers 0 and 1 as measurement target IDs to the frequency F1 and the frequency F2 as measurement targets, and notifies the terminal device 2 of them. Further, the base station apparatus 3 allocates identifiers 0, 1 and 2 as report setting IDs to report setting 1, report setting 2 and report setting 3 as report settings, and notifies the terminal apparatus 2. Furthermore, the base station device 3 notifies the terminal device 2 of the measurement ID linked (linked) to the combination of the identifier of the measurement target and the identifier of the report setting.

  In FIG. 10, a combination of the measurement target of the identifier 0 (frequency F1) and the report setting of the identifier 0 is designated as the 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 the measurement target of identifier 1 (frequency F2) and the report setting of identifier 2 is measurement. It is specified in ID # 2.

  Also, with measurement event information, for example, when the reception quality of the cell-specific reference signal of the serving cell falls below / above the predetermined threshold, the reception quality of the cell-specific reference signal of the neighboring cells is higher than that of the serving cell. When it falls below, it is the information which is formed from the measurement event which shows the condition such as when the reception quality of the neighboring cell exceeds the specified threshold, and the parameter which is used in order to decide that condition. Information such as a threshold value, an offset value, and a time required to establish a measurement event are set in the parameters. In Non-Patent Document 3, for example, it is defined that measurement event A1 is reported when the reception quality of a serving cell is better than a threshold. Further, it is defined that measurement event A3 is reported when the reception quality of the adjacent cell is better than the reception quality of the serving cell plus the offset value. Further, it is defined as measurement event A4 to report when the reception quality of the adjacent cell is better than the threshold.

  In step S92, the terminal device 2 stores the measurement setting information set from the base station device 3 as internal information, and then starts the measurement process. Specifically, as described above, the terminal device 2 manages the measurement ID, the measurement target ID, and the report setting ID in association so as to be linked to one, and performs measurement based on the measurement information corresponding to each ID. Start. When these three IDs are linked to one, it is regarded as valid and the related measurement is started, and when these three IDs are not linked to one (any ID is not set) If it is considered invalid, the related measurement is not started. Then, when the measurement setting information can be set without error, the terminal device 2 transmits a message (measurement setting completion message) indicating the completion of the measurement setting to the base station device 3 in step S93.

  Then, if any of the set measurement events satisfy the condition according to the parameter in the terminal device 2, the measurement report message is transmitted to the base station apparatus 3 assuming that the measurement event is triggered (trigger). Step S94). 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 related cell is set and reported. Since the base station apparatus 3 grasps to which measurement event report setting ID the measurement ID is linked, the terminal apparatus 2 does not need to notify the report setting ID in the measurement report message.

  A part of the handover procedure of the present embodiment will be described.

  FIG. 8 is a diagram showing an example of a handover procedure (procedure) in the present embodiment.

  (Step S801) If necessary, the base station device 3A sets the RRM measurement to the terminal device 2, and reports the cell (base station device 3B) of the handover candidate.

  (Step S802) The source base station device 3A determines the target base station device 3B based on the measurement result reported from the terminal device 2 and / or other judgment criteria, and performs handover to the target base station device 3B. Send a request (HANDOVER REQUEST) message (Send). The handover request message contains information necessary for handover preparation. For example, the handover request message may include information indicating the type of handover. Here, the information indicating the type of handover means at least whether it is a type of handover (hereinafter referred to as connection maintenance type handover) in which communication in the source cell is continued after receiving the handover command in step S805. It is desirable that it is information that can be judged. Also, for example, the handover request message includes information (for example, a part or all of the capability information of the terminal device 2) which can determine in which combination of bands the terminal device 2 can perform the connection maintenance type handover. It is also good.

  (Step S803) If the target base station 3B can accept the handover, the target base station 3B transmits a handover request acknowledgment (HANDOVER REQUEST ACKNOWLEDGE) message including a handover command to the source base station device 3A. The handover command is an RRC connection reconfiguration (RRC Connection Reconfiguration) message including mobility control information (mobilityControlInfo) that is a parameter. The parameter mobilityControlInfo may include information indicating the type of handover and information on the target cell. The information on the target cell may include information to indicate a physical layer cell identity (PCI) of the target cell, and information to indicate a frequency of the target cell. In step S803, in a situation where the handover can not be accepted, a handover preparation failure (HANDOVER PREPARATION FAILURE) message may be sent to the source base station apparatus 3A, and the subsequent steps may not be performed.

  (Step S804) The source base station device 3A transmits the handover command (RRC connection reconfiguration message) received from the source base station device 3A to the terminal device 2 using the PDSCH.

  (Step S805) The terminal device 2 having received a valid handover command from the source base station device 3A terminates communication in the source cell when the type of handover is conventional handover, and the target is determined in step S806 described later. Synchronize with the cell. When the type of handover is connection maintenance type handover, synchronization with the target cell is achieved in step S806 described later while the communication in the source cell is continued.

  That is, in the case of the conventional handover, the terminal device 2 receiving the handover command resets the MAC layer and starts reestablishing the PDCP layer and the RLC layer when starting downlink synchronization to the target cell. In the case of connection maintenance handover, when starting downlink synchronization to the target cell, MAC layer reset and PDCP layer and RLC layer reestablishment are not performed. For example, the MAC layer used for communication with the source cell may be reset after uplink resources are allocated in the target cell, or the RRC connection reconfiguration complete (RRCConnectionReconfigurationComplete) message to the target cell may be used. It may be performed after transmission.

In the case of connection-maintaining handover, some of the processes (A) to (D) shown below may be performed after receiving an RRC connection reconfiguration message including the parameter mobilityControlInfo. Alternatively, information indicating which process to perform may be included in the RRC connection reconfiguration message including the parameter mobilityControlInfo.
(A) When the SCG is set, the MAC layer of the MCG is not reset but the MAC layer of the SCG is reset.
(B) When the SCG is set, reestablishment of the PDCP layer and the RLC layer of the SCG is executed without executing reestablishment of the PDCP layer and the RLC layer of the MCG.
(C) Do not reset the MCG and SCG MAC layers.
(D) Do not execute reestablishment of PDCP layer and RLC layer of MCG and SCG.

  (Step S806) The terminal device 2 acquires downlink synchronization of the target cell based on the information on the target cell, and acquires uplink synchronization of the target cell by random access processing or other synchronization processing in the target cell.

  (Step S807) Further, in the random access process of step S806, the terminal device 2 acquires a PUSCH transmission resource and transmits uplink data. The uplink data may include an RRC connection reconfiguration complete message.

  (Step S808) The terminal device 2 that has transmitted the RRC connection reconfiguration complete message ends the communication in the source cell, resets each function of the MAC layer, if necessary, and performs PDCP layer exchange with the target cell. The RLC layer may be re-established.

  (Step S809) The target base station device 3B that has received the RRC connection reconfiguration complete message from the terminal device 2 sends a handover execution message to the source base station device 3A. The handover execution message is a message indicating that the RRC connection reconfiguration complete message has been received from the terminal device 2.

  (Step S810) The source base station device 3A that has received the handover execution message from the base station device 3B targets the PDCP SN (PDCP Sequence Number) or HFN (Hyper Frame Number) in uplink and downlink to the terminal device 2. It transfers to the base station apparatus 3B. PDCP SN and HFN are state variables used for concealment / decryption processing, header compression processing, and the like in the PDCP layer.

  (Step S811) Further, the source base station device 3A transfers, to the target base station device 3B, downlink data that has not been completely transmitted to the terminal device 2.

  (Step S812) The target base station device 3B transmits the downlink data transferred from the source base station device 3A to the terminal device 2.

  In addition, you may include the information (for example, PDCP SN, HFN, etc.) regarding the data which the terminal device 2 succeeded in the last reception in communication in a source cell in the RRC connection reset completion message of step S807. In this case, the base station device 3B may include, in the handover execution message in step S809, information on data finally successfully received in the communication in the source cell. Thus, in step S811, the base station device 3A can transfer only data that has not been received by the terminal device 2 yet.

  Radio link monitoring (RLM: Radio Link Monitoring) of this embodiment will be described.

  An example of an operation in which the RRC connected terminal device 2 detects a radio link failure (Radio Link Failure) will be described.

As shown in FIG. 17, first, the terminal device 2 in the RRC_IDLE state in which the RRC connection has not been established receives broadcast information from the located base station device 3 (step S171). The broadcast information includes various information on system information and establishment of RRC connection. As an example of parameters related to RRC connection establishment, timer T310 for detection of physical layer problems of PCell, timer T311 indicating a period in which RRC connection re-establishment processing can be performed, out-of? The threshold of the number of times of detection of sync) is N310, and the threshold of the number of times of detection of synchronization (in? sync) is N311.

In step S172, the terminal device 2 establishes an RRC connection with the base station device 3, transitions to the RRC_CONNECTED state, starts communication, and starts radio link monitoring (step S173).

Thereafter, when the terminal device 2 detects a loss of synchronization with the base station device 3 continuously N310 times during communication due to radio quality deterioration or the like in step S174, the terminal device 2 starts clocking of the timer T310 (step S175). Then, in step S176, when the synchronization (in? Sync) is continuously detected N311 times before the expiration of the timer T310, the terminal device 2 determines that the wireless quality deterioration state can be recovered, and stops the timer T310 ( Step S178), the communication is continued, and radio link monitoring is continued (transition to step S173). On the other hand, synchronization is continuously performed N311 times before the expiration of timer T310 (in? Sy
When the terminal device 2 can not detect nc) (step S177), the terminal device 2 detects a radio link failure in step S179. The operation after the wireless link failure detection differs in the operation of the terminal device 2 according to the establishment state of AS Security. First, when AS Security is not established, the terminal device 2 transitions to the RRC IDLE state, and when AS Security is established, the terminal device 2 executes an RRC connection reestablishment procedure. . Also, as the state of the timer, the state where the timer stopped (state before starting), the state where the timer is clocking (running), the time set without stopping by the time the timer was set has elapsed It may have a status (expire status).

  Radio link monitoring (RLM: Radio Link Monitoring) of the source cell at the time of connection maintenance type handover according to the present embodiment will be described.

When the terminal device 2 receives a valid handover command from the source base station device 3A in the connection-maintaining handover, the handover command includes a parameter t304 indicating a value to be set to the timer T304 indicating a period in which the handover process can be performed. In this case, the value of the t304 is set to the timer T304 and timer counting is started. When the type of handover is connection maintenance type handover, any of the following processes (A) to (C) may be performed.
(A) If the timer (T310) for counting the period of out-of-synchronization in communication with the source base station device 3A is counting, it continues without stopping the timer. If a synchronization loss with the base station device 3A is continuously detected N310 times due to radio quality deterioration of the source cell or the like during the connection-maintaining handover, the terminal device 2 starts clocking of the timer T310. Thereafter, when the synchronization (in? Sync) is continuously detected N311 times before the expiration of the timer T310, the terminal device 2 determines that the wireless quality deterioration state can be recovered, and stops the timer T310 to continue the communication. On the other hand, synchronization is continuously performed N311 times before the expiration of timer T310 (in? Sy
If the terminal device 2 can not detect nc), the terminal device 2 transitions to the RRC IDLE state, or
The C connection is not reestablished, and it is recorded that the source cell is in a radio link failure state (or timer T310 has expired).
(B) The process of starting / stopping / clocking the timer (T310) for measuring the period of out-of-synchronization in communication with the source base station device 3A is suspended (Suspend). During the connection-maintaining handover, even if the synchronization with the base station 3A is continuously detected N310 times due to radio quality deterioration of the source cell, etc., the terminal device 2 does not start the timer T310. Alternatively, out of sync detection is not performed.
(C) The process of starting / stopping / counting the timer (T310) for measuring the period of out-of-synchronization in communication with the source base station device 3A is suspended (Suspend). If a synchronization loss with the base station 3A is continuously detected N310 times due to radio quality deterioration of the source cell or the like during connection-maintaining handover, the terminal device 2 starts clocking of a timer T31x different from the timer T310. After that, synchronization continues N311 times before the expiration of the timer T31x (in? S
When detecting ync), the terminal device 2 determines that the wireless quality deterioration state has been recovered, and stops the timer T310 to continue communication. On the other hand, when the synchronization (in? Sync) can not be detected N311 times continuously by the expiration of the timer T31x, the terminal device 2 indicates that the source cell is in the radio link failure state (or the timer T31x has expired). Record. It is desirable that the value set in the timer T31x be larger than the maximum value that can be set in T310. In addition, infinity may be set as a value to T31x.

When the handover to the target cell is not completed normally before the timer T304 expires, the terminal device 2 performs the following process (A ′) corresponding to the above processes (A) to (C) when the timer T304 expires. ) To (C ') may be performed.
(A ′) If the source cell is not in the radio link failure state (the timer T310 is not in the expired state), the source cell is notified of a handover failure to the target cell. On the other hand, if the source cell is in the radio link failure state (the timer T310 has expired), the RRC connection re-establishment procedure is initiated. That is, when the result of radio link monitoring by the continued timer T310 in the source cell can not notify the source cell of a failure in handover to the target cell due to radio link failure, a cell connection re-establishment procedure is performed.
(B ') Resume (resume) the process of starting / stopping / clocking the timer (T310) that has been suspended, and notify the source cell of the failure of the handover to the target cell. That is, when the radio link monitoring in the source cell is performed by resumption of the timer T310, and a failure in handover to the target cell can not be notified to the source cell due to radio link failure, a cell connection reestablishment procedure is performed. Further, at this time, if the timer T310 is suspended (Suspend) in the middle of clocking, the subsequent clock may be clocked.
(C ′) Resume (resume) the process of starting / stopping / clocking the timer (T310) that has been paused. When the timer T31x is stopped, the source cell is notified of the failure of the handover to the target cell. On the other hand, if the timer T31x is clocking or has expired, the cell connection reestablishment procedure is executed. That is, when radio link monitoring by the timer T31x in the source cell can not notify the source cell of a failure in handover to the target cell due to radio link failure, a cell connection re-establishment procedure is executed.

  In the above process, in order to suppress a change to the conventional process (such as execution of the RRC connection re-establishment procedure) due to the expiration of the timer T304, another timer independent of the timer T304 at the time of connection maintenance type handover instead of the timer T304. The failure of the handover may be determined using In this case, the value of t304 included in the handover command may be set as the value of the timer, or a value notified by another parameter may be set.

  The RRC connection re-establishment of this embodiment will be described.

In the case where the terminal device 2 can not comply with, for example, some or all of the settings included in the RRC connection reconfiguration message notified from the base station device 3 and the security of the AS layer is in the activated state (Activated) Or if the radio link fails ((1) timer T310, which starts counting when a problem in the physical layer is detected, expires (2) it is set at the time of measurement, and measurement report is triggered during timer T310 timing (3) Timer T 300 starts counting when transmitting an RRC connection request message and timer T 301 starts counting when transmitting an RRC connection reestablishment request message when the timer T 312 starts counting. Start timing when receiving RRC connection reconfiguration message including control information When the random access problem is indicated from the MAC layer when neither the timer T304 nor the timer T311 which starts counting when starting the RRC connection re-establishment procedure shows (4) the maximum number of retransmissions from the RLC layer (5) when the handover to the target cell fails in connection-maintaining handover, when the radio link of the source cell fails, and so forth, and the security of the AS layer Is activated (Activated), or when a handover fails, etc., the RRC connection re-establishment procedure is performed to maintain the connected state (radio resource control connection).

  The RRC connection re-establishment is successful only when (the base station device 3 of) the cell that has attempted to connect is ready (has the context of the valid terminal device 2). However, the base station device 3 not having the context of the terminal device 2 can also succeed in RRC connection re-establishment by acquiring a valid context from the base station device 3 having the context of the terminal device 2 It becomes.

  As the RRC connection re-establishment procedure, first, if the timer T310 and the timer T312 are clocking, the terminal device 2 stops the clocking of each and starts the clocking of the timer T311. Next, the radio bearers other than SRB0 are suspended. Next, the MAC layer is reset, and default settings are applied to the MAC layer and physical layer to start the cell selection procedure.

  When the optimal cell is selected according to the RRC connection re-establishment procedure, the terminal device 2 stops the timer T311 and starts timing of the timer T301, and the connection re-establishment request message to the base station device 3 in the selected cell. Send The connection re-establishment request message includes information indicating the reason for RRC connection re-establishment (such as re-establishment failure, handover failure, and other failures).

  Upon receiving the RRC connection reestablishment message from the base station device 3, the terminal device 2 that has transmitted the RRC connection reestablishment request message stops counting of the timer T301, and reestablishes PDCP and RLC of SRB1. Further, the radio resource is set, and the temporarily suspended SRB 1 is resumed (Resume). Then, secrecy (Integrity) and encryption (Ciphering) are performed using the settings before RRC connection re-establishment, and when the processing is normally completed, an RRC re-establishment completion message is notified to base station apparatus 3 .

  When the optimal cell is not selected by the RRC connection re-establishment procedure, the timer T 311 expires, the RRC connection fails, and the terminal device 2 transitions from the connected state to the idle state. Also, when the timer T301 expires or the selected optimal cell does not meet the cell selection criteria, the RRC connection fails, and the terminal device 2 is in the idle state from the connected state. Transition to

  The carrier aggregation of this embodiment will be described.

  In the present embodiment, the terminal device 2 may set a plurality of serving cells in communication with the base station device 3. A technology in which the terminal device 2 communicates with the base station device 3 via a plurality of serving cells is referred to as cell aggregation or carrier aggregation. In carrier aggregation, a plurality of configured serving cells are also referred to as aggregated serving cells.

  TDD (Time Division Duplex) and / or FDD (Frequency Division Duplex) are applied to the wireless communication system of this embodiment. In the case of cell aggregation, TDD may be applied to all of a plurality of serving cells. In the case of cell aggregation, a serving cell to which TDD is applied and a serving cell to which FDD is applied may be aggregated. In the present embodiment, the serving cell to which TDD is applied is also referred to as a TDD serving cell.

  The plurality of configured serving cells include one primary cell and one or more secondary cells. The primary cell is a serving cell on which an initial connection establishment procedure has been performed, a serving cell on which a connection re-establishment procedure has been started, or a cell designated as a primary cell in a handover procedure. A secondary cell may be configured when or after an RRC (Radio Resource Control) connection is established.

  The primary cell includes a source primary cell and a target primary cell.

  In downlink, a carrier corresponding to a serving cell is referred to as a downlink component carrier. In uplink, a carrier corresponding to a serving cell is referred to as an uplink component carrier. The downlink component carrier and the uplink component carrier are collectively referred to as a component carrier.

  The terminal device 2 can perform simultaneous transmission of a plurality of physical channels / a plurality of physical signals in a plurality of serving cells (component carriers) to be aggregated. The terminal device 2 can simultaneously receive a plurality of physical channels / a plurality of physical signals in a plurality of serving cells (component carriers) to be aggregated.

  In addition, with respect to the state of the serving cell, the cell has an activated state and a deactivated state. The primary cell is not subject to activation and deactivation control (that is, the primary cell is always considered to be activated), but the secondary cell is said to be activated and deactivated. It has the state of the cell according to the activity.

  The dual connectivity of this embodiment will be described.

  In the present embodiment, the terminal device 2 may set a plurality of serving cells in communication with the plurality of base station devices 3. A technique in which the terminal device 2 communicates with a plurality of base station devices 3 via a plurality of serving cells is referred to as dual connectivity.

  In carrier aggregation, one base station apparatus 3 manages a plurality of cells, and one base station apparatus 3 can centrally control one cell for each cell, and a backbone link between a plurality of cells is affected by delay. It is different from the connection by dual connectivity that it is not necessary to consider. In other words, while carrier aggregation is a technology for connecting one terminal device 2 and one base station device 3 via a plurality of cells, dual connectivity is achieved by connecting one terminal device 2 and a plurality of base stations. This is a technology to connect the station apparatus 3 via a plurality of cells.

  In dual connectivity, two cell groups are defined: a cell group including a primary cell (MCG: Master eNB Cell Group) and a cell group not including a primary cell (SCG: Secondary eNB Cell Group).

A terminal apparatus and a base station apparatus can apply the technology applied to carrier aggregation to dual connectivity. For example, the terminal device 2 and the base station device 3 connect technologies such as management (addition, deletion, change, etc.) of primary cells and secondary cells, RRM measurement corresponding to carrier aggregation, activation / deactivation, etc. by dual connectivity. May be applied to the cell being

  Also, with regard to the state of the serving cell (state), in the carrier aggregation, the primary cell is not subject to activation and deactivation control, but in dual connectivity, one of the MCG primary cell and one of the SCGs. Cells (referred to as PSCells) are excluded from the control of Activation and Deactivation.

  Typically, carrier aggregation uses a user plane protocol stack with one layer for each layer as shown in FIG. 4, but dual connectivity uses a protocol stack in which the RLC layer and below are separated for each cell group Be Therefore, one base station apparatus 3 may be connected to the terminal apparatus 2 with dual connectivity using a plurality of protocol stacks.

  The transmission of uplink data according to this embodiment will be described below.

  The physical uplink control channel PUCCH is a request for transmission of downlink data response (ACK / NACK) transmitted on the physical downlink shared channel PDSCH, downlink radio channel quality information (Channel Quality Indicator: CQI), and uplink data. It is used for transmission of (Scheduling Request (SR)). When the terminal device 2 makes a transmission request for uplink data, it transmits a scheduling request to the base station device 3 using the physical uplink control channel PUCCH allocated from the base station device 3. When no physical uplink resources are allocated from the base station device 3, uplink resources are requested by a random access procedure.

  The random access procedure of this embodiment will be described below.

Contention based random access procedure (Contention)
There are two access procedures: based Random Access procedure) and non-contention based Random Access procedure.

  The contention-based random access procedure is a random access procedure that may cause a collision between the terminal devices 2 and is in connection with the base station device 3 or at the time of initial access from a state not connected (communicated) with the base station device 3. However, it is performed as a scheduling request or the like when uplink data transmission occurs in the terminal device 2 in a state where uplink synchronization is out.

  The non-contention based random access procedure is a random access procedure in which no collision occurs between the terminal devices 2, and when the base station device 3 and the terminal device 2 are connected but uplink synchronization is out of order, quickly. In order to achieve uplink synchronization between the terminal device 2 and the base station device 3, the terminal device 2 is instructed randomly by the base station device 3 in a special case such as when handover or transmission timing of the terminal device 2 is not effective. Start the access procedure. The non-contention based random access procedure is instructed by RRC (Radio Resource Control: Layer 3) layer messages and control data of physical downlink control channel PDCCH.

  The contention based random access procedure will be briefly described using FIG. First, the terminal device 2 transmits a random access preamble to the base station device 3 (message 1: (1), step S61). Then, the base station device 3 having received the random access preamble transmits a response (random access response) to the random access preamble to the terminal device 2 (message 2: (2), step S62). The terminal device 2 transmits a message of the upper layer (Layer2 / Layer3) based on the scheduling information included in the random access response (message 3: (3), step S63). The base station device 3 transmits a collision confirmation message to the terminal device 2 that has received the upper layer message of (3) (message 4: (4), step S64). Note that contention based random access is also referred to as random preamble transmission.

  Next, the non-contention based random access procedure will be briefly described using FIG. First, the base station apparatus 3 notifies the terminal apparatus 2 of the preamble number (or sequence number) and the random access channel number to be used (message 0: (1) ', step S71). The terminal device 2 transmits the random access preamble of the designated preamble number to the designated random access channel RACH (message 1: (2) ', step S72). Then, the base station device 3 having received the random access preamble transmits a response (random access response) to the random access preamble to the terminal device 2 (message 2: (3) ', step S73). However, when the value of the notified preamble number is 0, the contention based random access procedure is performed. The non-contention based random access procedure is also referred to as dedicated preamble transmission.

  The configuration of the terminal device capability of this embodiment will be described.

  In the terminal device 2, the function of the wireless transmission / reception unit 20 differs for each terminal device 2. That is, combinations of bands (carriers, frequencies) to which carrier aggregation can be applied are different for each terminal device 2. Therefore, the terminal device 2 notifies the base station device 3 of RF-Parameters-v 1020 which is information / parameter indicating a combination of bands to which carrier aggregation can be applied (band combination). Hereinafter, a band to which carrier aggregation can be applied is also referred to as a CA band. A band to which carrier aggregation can not be applied or a band to which carrier aggregation can be applied but to which carrier aggregation is not applied is also referred to as a non-CA band.

  FIG. 11 is a diagram showing information / parameters included in RF-Parameters-v 1020 of the present embodiment. RF-Parameters-v1020 includes one SupportedBandCombination-r10. SupportedBandCombination-r10 includes one or more BandCombinationParameters-r10. SupportedBandCombination-r10 includes supported CA band combinations and supported non-CA bands.

BandCombinationParameters-r10 includes one or more BandParameters-r10. One Band Combination Parameters-r10 indicates a combination of supported CA bands or a supported non-CA band. For example, when a plurality of BandParameters-r10 are included in BandCombinationParameters-r10, communication to which carrier aggregation in a combination of CA bands indicated by the plurality of BandParameters-r10 is supported is supported. In addition, BandCombinationParameters-one band in r10
When Parameters-r10 is included, communication in the band (non-CA band) indicated by the one BandParameters-r10 is supported.

  FIG. 12 is a diagram showing information / parameters included in BandParameters-r10 of the present embodiment. BandParameters-r10 includes bandEUTRA-r10, bandParametersUL-r10, and bandParametersDL-r10.

  bandEUTRA-r10 includes FreqBandIndicator. FreqBandIndicator indicates a band. If the terminal device 2 does not have the ability to transmit uplink signals in the band indicated by FreqBandIndicator, bandParameters UL-r10 is not included in BandParameters-r10. When the terminal device 2 does not have the capability to receive the downlink signal in the band indicated by FreqBandIndicator, bandParametersDL-r10 is not included in BandParameters-r10.

  bandParametersUL-r10 includes one or more CA-MIMO-ParametersUL-r10. CA-MIMO-ParametersUL-r10 includes ca-BandwidthClassUL-r10 and supportedMIMO-CapabilityUL-r10. ca-BandwidthClassUL-r10 includes CA-BandwidthClass-r10.

  supportedMIMO-CapabilityUL-r10 indicates the number of layers supported for spatial multiplexing in the uplink. When spatial multiplexing is not supported in uplink, supported MIMO-CapabilityUL-r10 is not included in CA-MIMO-ParametersUL-r10.

  The bandParametersDL-r10 includes one or more CA-MIMO-ParametersDL-r10. CA-MIMO-ParametersDL-r10 includes ca-BandwidthClassDL-r10 and supportedMIMO-CapabilityDL-r10. ca-BandwidthClassDL-r10 includes CA-BandwidthClass-r10.

  supportedMIMO-CapabilityDL-r10 indicates the number of layers supported by spatial multiplexing in downlink. When spatial multiplexing is not supported in downlink, supported MIMO-CapabilityUL-r10 is not included in CA-MIMO-ParametersDL-r10.

CA-BandwidthClass-r10 indicates a CA bandwidth class supported by the terminal device 2 in uplink or downlink. The CA-BandwidthClassUL-r10 corresponds to the CA bandwidth class supported by the terminal device 2 in the uplink. The CA-BandwidthClassDL-r10 corresponds to the CA bandwidth class supported by the terminal device 2 in downlink. The CA bandwidth class is defined by the number of cells that can be simultaneously set by the terminal device 2 in the band indicated by FreqBandIndicator, the sum of bandwidths of cells simultaneously set in the band indicated by FreqBandIndicator, and the like. For example, the CA bandwidth class a indicates that one cell of 20 MHz or less can be configured.

  FIG. 13 is a diagram showing an example of RF-Parameters-v 1020 according to the present embodiment. For example, RF-Parameters-v1020 includes one SupportedBandCombination-r10. As described above, SupportedBandCombination-r10 includes one or more BandCombinationParameters-r10. In addition, BandCombinationParameters-r10 includes one or more BandParameters-r10.

  Band Combination Parameters-r10 of BCP 13100 indicates that transmission in uplink can be performed in one cell in Band A, and transmission in downlink can be performed in one cell in Band A. That is, Band Combination Parameters-r10 of BCP 13100 indicates that Band A supports one cell. In addition, Band Combination Parameters-r10 of BCP 13100 indicates that two layers are supported for spatial multiplexing in the downlink of Band A. In addition, Band Combination Parameters-r10 of BCP 13100 indicates that spatial multiplexing is not supported in the uplink of Band A.

Band Combination Parameters-r10 of BCP 13300 can transmit in uplink in one cell in Band A, can transmit in downlink in one cell in Band A, and transmits in downlink in one cell in Band B Indicates that it is possible. That is, BandCombinationParameters-r10 of BCP 13100 is a Band.
It is shown that a combination of one primary cell in A and one secondary cell without uplink in Band B is supported. In addition, Band Combination Parameters-r10 of BCP 13300 indicates that the spatial multiplexing in the downlink of Band A, the spatial multiplexing in the downlink of Band B, and the spatial multiplexing in the uplink of Band A are not supported.

  Furthermore, the terminal device 2 notifies the base station device 3 of not only carrier aggregation but also information / parameters indicating a combination of bands (carriers, frequencies) to which dual connectivity can be applied (band combination).

  FIG. 14 is a diagram showing information / parameters included in RF-Parameters-v 1250 of this embodiment. The RF-Parameters-v 1250 may include one supportedBandListE-UTRA-v 1250, one supportedBandCombination-v 1250, one supportedBandCombinationAdd-v 1250, one freqBandPriorityAdjustment-r12, or a combination thereof.

  supportedBandList E-UTRA-v 1250 may include one or more Supported Band E-UTRA-v 1250. The Supported Band E-UTRA-v 1250 may include, for each band supported by the terminal device 2, information indicating whether 256 QAM reception is supported in downlink or 64 QAM transmission in uplink.

  The list of bands supported by the terminal device 2 is indicated by SupportedBandListE-UTRA included in RF-Parameters (which is a parameter including RF-Parameters-v 1250). The order of SupportedBandE-UTRA-v1250 included in supportedBandListE-UTRA-v1250 and the order of bands shown in SupportedBandListE-UTRA correspond one-to-one.

  The SupportedBandCombination-v 1250 and the supportedBandCombinationAdd-v 1250 may include BandCombinationParameters-v 1250 for each combination of bands supported by the terminal device 2. BandCombinationParameters-v1250 may include dc-Support-r12, which is information on dual connectivity.

  Note that the order of BandCombinationParameters-v1250 included in supportedBandCombination-v1250 and supportedBandCombinationAdd-v1250 corresponds to the order of the list of band combinations indicated by SupportedBandCombination-r10 one to one.

  When the BandCombinationParameters-v 1250 includes dc-Support-r12, it indicates that the terminal device 2 supports synchronous dual connectivity in which at least MCG and SCG are synchronized. We also show that if dc-Support-r12 is included for a combination of bands consisting of only one band, it supports dual connectivity with consecutive bands within the band. Also, when dc-Support-r12 includes asynchronous-r12, it indicates that the terminal device 2 supports asynchronous dual connectivity between MCG and SCG.

Typically, since these parameters do not dynamically change during communication, terminal device 2 is statically set in terminal device 2 such as non-volatile memory as a system parameter. The terminal device capability is configured based on the capability information of the terminal device 2, and the terminal device capability message including the terminal device capability is an RRC message when connected with the base station device 3 or in response to a request from the base station device 3. To the base station apparatus 3 as

  For example, as shown in FIG. 16, the base station apparatus 3 transmits a message (UECapabilityEnquiry) for requesting notification of the terminal apparatus capability to the terminal apparatus 2 (step S161). The terminal device 2 transmits an RRC message (UECapabilityInformation) including the information of the terminal device capability to the base station device 3 based on the information included in the UECapabilityEnquiry (step S162). At this time, UECapabilityInformation may include information on connection maintenance type handover, which will be described later, in the UECapabilityInformation.

  The base station device 3 receives the terminal device capability message, and can appropriately set the component carrier (cell) for the terminal device 2 based on the notified terminal device capabilities.

The terminal device capability notification method regarding connection maintained handover in this embodiment will be described.

  (Notification method 1) The terminal device 2 notifies the base station device 3 of RF-Parameters-rX which is information / parameter indicating a combination of bands to which connection maintenance type handover can be applied (band combination).

  FIG. 15 is a diagram showing an example of information / parameters included in RF-Parameters-rX of the present embodiment. RF-Parameters-rX includes one SupportedBandCombination-rX. In SupportedBandCombination-rX, BandCombinationParameters-rX may be included for each combination of bands supported by the terminal device 2.

  BandCombinationParameters-rX may include a parameter (cmho-Support-rX) indicating whether or not the connection-sustaining type handover is possible.

cmho-Support-rX may include information indicating to which band connection-maintaining handover can be performed in a combination of designated bands. For example, information of part or all of the following (A) to (G) may be included.
(A) Information for grouping a combination of bands into two. (Consider that connection-maintained handover from one group containing the band of the source cell to the other group is possible)
(B) Information indicating whether connection-maintaining handover is possible within one band.
(C) Information indicating whether connection-maintaining handover is possible between a plurality of bands.
(D) Information indicating whether connection-maintaining handover is possible within the same frequency in one band.
(E) Information indicating whether connection-maintaining handover is possible between different frequencies in one band.
(F) Bit information corresponding to each band included in the combination of bands. (Consider that connection-maintaining handover to the band where the bit is set is possible)
(G) Bit information corresponding to each band included in the combination of bands. (Consider that connection-sustaining handover to the band where the bit is set is impossible)

  In the above (B) to (E), in the case where there are a plurality of target bands, single bits may indicate whether or not all the target bands are present, and it is possible to correspond to each target band. Each bit can be indicated by a bit string.

  Note that the order of BandCombinationParameters-rX included in SupportedBandCombination-rX and the order of the list of band combinations indicated by SupportedBandCombination-r10 may correspond one to one. Alternatively, RF-Parameters-rX may include band combination information corresponding to the order of BandCombinationParameters-rX and one-to-one correspondence. The combination information of the band at this time may include some or all of the components of SupportedBandCombination-r10.

  In addition, cmho-Support-rX may include separate parameters for uplink and downlink.

Further, UECapabilityEnquiry notified from the base station apparatus 3 includes information as to whether or not to notify information on the terminal apparatus capability regarding connection maintenance type handover, and based on the information, the terminal apparatus 2 is a terminal regarding connection maintenance type handover It may be determined whether to notify information of the device capability.

  By configuring as in the notification method 1, the terminal device 2 can efficiently notify the base station device 3 of the terminal device capability related to the connection maintained handover.

  (Notification method 2) The terminal device 2 applies a connection-maintaining handover in a combination of SupportedBandCombination-v 1250 which is information / parameter indicating a combination of bands to which dual connectivity can be applied (band combination) and the band to which the dual connectivity can be applied. The base station apparatus 3 is notified of one or more bit information indicating whether it can be performed.

  The bit information may be included in a parameter (for example, RF-Parameters) included in a parameter UE-E-UTRA-Capability notifying terminal device capability.

For example, according to the bit information, the terminal device 2 and the base station device 3 interpret that part or all of the following (A) to (C) holds.
(A) When support is indicated by bit information, connection maintenance type handover is possible in a combination of bands in which dc-Support-r12 is included in BandCombinationParameters-v1250.
(B) When support is indicated by bit information, connection-combining handover is possible in a combination of bands including dc-support-r12 in BandCombinationParameters-v1250 and asynchronous-r12 in dc-Support-r12. .
(C) If connectivity is indicated by bit information, dual connectivity at the same frequency is possible.

Furthermore, when the bit information is a plurality of bits, in (A) and (B), part or all of the following (D) to (G) may be indicated.
(D) Whether or not connection maintained handover is possible within one band.
(E) Whether or not connection maintenance type handover is possible between a plurality of bands.
(F) Whether or not connection maintained handover is possible within the same frequency within one band.
(G) Whether or not connection maintained handover can be performed between different frequencies in one band.

  Note that the order of BandCombinationParameters-rX included in SupportedBandCombination-rX and the order of the list of band combinations indicated by SupportedBandCombination-r10 may correspond one to one. Alternatively, RF-Parameters-rX may include band combination information corresponding to the order of BandCombinationParameters-rX and one-to-one correspondence.

  Further, UECapabilityEnquiry notified from the base station apparatus 3 includes information as to whether or not to notify information on the terminal apparatus capability regarding connection maintenance type handover, and based on the information, the terminal apparatus 2 is a terminal regarding connection maintenance type handover It may be determined whether to notify information of the device capability.

By configuring as in the notification method 2, the terminal device 2 efficiently notifies the base station device 3 of the terminal device capability regarding connection maintenance type handover by diverting the notification parameter of the terminal device capability regarding dual connectivity. Can. Further, the base station apparatus 3 can use the terminal apparatus capability related to dual connectivity based on the bit information notified from the terminal apparatus 2 for the interpretation of the terminal apparatus capability related to the connection maintenance type handover, and the efficient terminal apparatus capacity It becomes possible to acquire.

  (Notification method 3) In RRM measurement, the terminal device 2 notifies the base station device 3 whether or not the connection maintenance type handover is possible in the measurement report.

  The terminal device 2 is allocated one or more frequencies to be measured as a setting of RRM measurement. Therefore, the terminal device 2 may add, at the time of reporting of the RRM measurement, information indicating whether or not connection maintenance type handover is possible for each frequency to be measured. At this time, when it is determined whether or not the connection maintenance type handover is possible, a connection maintenance type handover capable frequency may be indicated in the assumption that only PCell (or only MCG) connection is maintained, or SCG is set. In this case, it is possible to indicate a connection maintenance type handover-enabled frequency in the assumption of maintaining the connection between the PCell and the PSCell.

  Further, the RRM measurement setting set from the base station apparatus 3 includes information as to whether or not to notify information on connection maintained handover, and the terminal apparatus 2 measures information on connection maintained handover based on the information. It may be determined whether to notify by report.

  By configuring as in Notification method 3, the terminal device 2 can efficiently perform the connection maintenance type handover availability status in the current serving cell without notifying a large amount of connection maintenance type handover terminal equipment capability information. The device 3 can be notified.

  Hereinafter, the configuration of the device in the embodiment of the present invention will be described.

  FIG. 2 is a schematic block diagram showing the configuration of the terminal device 2 of the present embodiment. As illustrated, the terminal device 2 is configured to include a wireless transmission / reception unit 20 and an upper layer processing unit 24. The wireless transmission and reception unit 20 includes an antenna unit 21, an RF (Radio Frequency) unit 22, and a baseband unit 23. The upper layer processing unit 24 includes a medium access control layer processing unit 25 and a radio resource control layer processing unit 26. The wireless transmission / reception unit 20 is also referred to as a transmission unit, a reception unit, or a physical layer processing unit.

  The upper layer processing unit 24 outputs uplink data (transport block) generated by a user operation or the like to the radio transmission / reception unit 20. The upper layer processing unit 24 includes a medium access control (MAC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a radio resource control (radio). Resource Control (RRC) layer processing is performed.

  The medium access control layer processing unit 25 included in the upper layer processing unit 24 performs processing of the medium access control layer. The medium access control layer processing unit 25 controls transmission of a scheduling request based on various setting information / parameters managed by the radio resource control layer processing unit 26.

The radio resource control layer processing unit 26 included in the upper layer processing unit 24 performs processing of the radio resource control layer. The radio resource control layer processing unit 26 manages various setting information / parameters of its own device. The radio resource control layer processing unit 26 sets various setting information / parameters based on the signal of the upper layer received from the base station apparatus 3. That is, the radio resource control layer processing unit 26 sets various setting information / parameters based on information indicating various setting information / parameters received from the base station apparatus 3.

  The wireless transmission / reception unit 20 performs physical layer processing such as modulation, demodulation, coding, and decoding. The wireless transmission and reception unit 20 separates, demodulates and decodes the signal received from the base station apparatus 3, and outputs the decoded information to the upper layer processing unit 24. The wireless transmission / reception unit 20 generates a transmission signal by modulating and encoding data, and transmits the transmission signal to the base station apparatus 3.

  The RF unit 22 converts a signal received via the antenna unit 21 into a baseband signal by orthogonal demodulation (down conversion: down cover), and removes unnecessary frequency components. The RF unit 22 outputs the processed analog signal to the baseband unit.

The baseband unit 23 converts an analog signal input from the RF unit 22 into a digital signal. The baseband unit 23 generates a CP (Cyclic) signal from the converted digital signal.
Fast Fourier transform (F) on the signal from which the portion corresponding to Prefix is removed and CP is removed.
Ast Fourier Transform (FFT) is performed to extract a signal in the frequency domain.

  The baseband unit 23 performs Inverse Fast Fourier Transform (IFFT) on the data to generate an SC-FDMA symbol, adds a CP to the generated SC-FDMA symbol, and generates a baseband digital signal. It generates and converts a baseband digital signal into an analog signal. The baseband unit 23 outputs the converted analog signal to the RF unit 22.

  The RF unit 22 removes extra frequency components from the analog signal input from the baseband unit 23 using a low pass filter, up-converts the analog signal to a carrier frequency, and transmits it via the antenna unit 21. Do. Also, the RF unit 22 amplifies the power. Also, the RF unit 22 may have a function of controlling transmission power. The RF unit 22 is also referred to as a transmission power control unit.

  The terminal device 2 is configured to include a plurality of parts or all of each part in order to support transmission / reception processing in a plurality of frequencies (frequency band, frequency bandwidth) or cells in the same subframe by carrier aggregation. It is also good.

  FIG. 3 is a schematic block diagram showing the configuration of the base station device 3 of the present embodiment. As illustrated, the base station device 3 is configured to include a wireless transmission / reception unit 30 and an upper layer processing unit 34. The wireless transmission and reception unit 30 includes an antenna unit 31, an RF unit 32, and a baseband unit 33. The upper layer processing unit 34 includes a medium access control layer processing unit 35 and a radio resource control layer processing unit 36. The wireless transmission / reception unit 30 is also referred to as a transmission unit, a reception unit, or a physical layer processing unit.

The upper layer processing unit 34 performs medium access control (MAC: Medium Access C).
ontrol layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, radio resource control (radio resource)
Control (RRC) layer processing is performed.

  The medium access control layer processing unit 35 provided in the upper layer processing unit 34 performs processing of the medium access control layer. The medium access control layer processing unit 35 performs processing related to a scheduling request based on various setting information / parameters managed by the radio resource control layer processing unit 36.

  The radio resource control layer processing unit 36 included in the upper layer processing unit 34 performs processing of the radio resource control layer. The radio resource control layer processing unit 36 generates downlink data (transport block), system information, RRC message, MAC CE (Control Element), etc. allocated to the physical downlink shared channel, or acquires it from the upper node. , To the wireless transmission and reception unit 30. The radio resource control layer processing unit 36 also manages various setting information / parameters of each of the terminal devices 2. The radio resource control layer processing unit 36 may set various setting information / parameters for each of the terminal devices 2 via the upper layer signal. That is, the radio resource control layer processing unit 36 transmits / broadcasts information indicating various setting information / parameters.

  The function of the wireless transmission / reception unit 30 is the same as that of the wireless transmission / reception unit 20, and thus the description thereof is omitted.

  Further, the upper layer processing unit 34 transmits (transfers (transfers) user data or a control message between the base station apparatus 3 or the upper network apparatus (MME, S-GW (Serving-GW)) and the base station apparatus 3. Or receive. Although other components of the base station apparatus 3 and transmission paths of data (control information) between the components are omitted in FIG. 3, other functions necessary to operate as the base station apparatus 3 are not included. It is obvious that it has a plurality of blocks which it has as a component. For example, above the radio resource control layer processing unit 36, a radio resource management (Radio Resource Management) layer processing unit and an application layer processing unit exist.

  Note that "part" in the figure is an element that implements the functions and procedures of the terminal device 2 and the base station device 3, which are also expressed in terms of sections, circuits, configuration devices, devices, units and the like.

  Each of the units denoted by reference numerals 10 to 16 included in the terminal device 2 may be configured as a circuit. Each of the units from 30 to 36 included in the base station apparatus 3 may be configured as a circuit.

  Hereinafter, various aspects of the terminal device 2 and the base station device 3 in the embodiment of the present invention will be described.

  (1) A first aspect of the present invention is a terminal apparatus that communicates with a base station apparatus via a cell, and in a first cell, a base station apparatus performs a handover command instructing handover to a second cell. And when the first timer has expired, if the second timer is counting or expiring, it considers it as a radio link failure and performs radio resource control (RRC) re-establishment and the first timer expires If the second timer is not counting time or has not expired, it is not considered as a radio link failure and does not perform radio resource control (RRC) re-establishment, and the first timer starts counting when a handover command is received. The second timer starts counting when a predetermined number of consecutive out-of-sync conditions in the first cell are detected, and continues to synchronize in the first cell. A timer that stops the counter when a constant number of times detected.

  (2) In the first aspect of the present invention, the second timer further receives a handover command when the handover is a handover that does not continue communication with the first cell after receiving the handover command. After that, the clocking is stopped, and the clocking is continued if the handover is a handover in which communication with the first cell is continued after receiving the handover command.

(3) In the first aspect of the present invention, when the second timer is a handover in which communication with the first cell is continued even after receiving the handover command, the second timer receives the handover command. Do timekeeping.

  (4) A second aspect of the present invention is a base station apparatus for communicating with a terminal apparatus, which transmits to the terminal apparatus a handover command instructing handover from the first cell to the second cell, In the terminal device, the timer includes a value to be set to the first timer in the first cell if the handover is a handover in which communication with the first cell continues even after receiving the handover command. Used to determine the radio link failure of

  (5) A third aspect of the present invention is an integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell, and instructs a handover to a second cell in the first cell. A function of receiving a handover command from the base station apparatus, and radio resource control (RRC) reestablishment as radio link failure when the second timer is counting or expiration when the first timer expires. The terminal device has a function to perform, and a function that does not consider radio link failure and does not perform radio resource control (RRC) re-establishment if the second timer is not counting or is not counting when the first timer has expired. The first timer is a timer that starts counting when a handover command is received, and the second timer continuously loses synchronization in the first cell. It starts timing when constant frequency detecting a timer to stop the counting when the predetermined number of times detected state of synchronization in the first cell in succession.

  (6) A fourth aspect of the present invention is an integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell, and instructs a handover to a second cell in the first cell. Receiving a handover command from the base station device, and considering the radio link failure if the second timer is counting or expiring when the first timer expires, reestablishing radio resource control (RRC) Performing at least a step of not considering radio link failure and not performing radio resource control (RRC) reestablishment if the second timer is not counting or not timing when the first timer expires. Is a timer that starts counting when a handover command is received, and the second timer is a predetermined number of consecutive out-of-sync conditions in the first cell. It starts timing when issuing a timer to stop the counting when the predetermined number of times detected state of synchronization in the first cell in succession.

  By this means, the terminal device 2 can efficiently notify the base station device 3 of the terminal device capability related to the connection maintained handover.

  The embodiments described above are merely examples, and can be realized using various modifications and substitution examples. For example, the uplink transmission scheme is applicable to both FDD (Frequency Division Duplex) and TDD (Time Division Duplex) communication systems. Further, the names of the respective parameters and the respective events shown in the embodiments are referred to for convenience of explanation, and even if the names actually applied are different from the names of the embodiments of the present invention, the present invention is not limited thereto. It does not affect the spirit of the claimed invention in the embodiments of the invention.

  In addition, “connection” used in each embodiment is not limited to a configuration in which one device and another device are directly connected using physical lines, but is logically connected. And wirelessly connected using wireless technology.

The terminal device 2 is also referred to as a user terminal, a mobile station device, a communication terminal, a mobile station, a terminal, a UE (User Equipment), and an MS (Mobile Station). The base station apparatus 3 includes a radio base station apparatus, a base station, a radio base station, a fixed station, an NB (Node B), an eNB (evolved Node B), and a BTS (Base Transceiver Stat).
ion) and BS (Base Station).

  The base station device 3 according to the present invention can also be realized as an aggregate (device group) composed of a plurality of devices. Each of the devices forming the device group may include all or part of each function or each functional block of the base station device 3 according to the above-described embodiment. It is sufficient to have one function or each functional block of the base station apparatus 3 as an apparatus group. In addition, the terminal device 2 related to the above-described embodiment can also communicate with the base station device 3 as an aggregate.

  Also, the base station device 3 in the above-described embodiment may be an EUTRAN (Evolved Universal Terrestrial Radio Access Network). Also, the base station device 3 in the above-described embodiment may have some or all of the functions of the upper node for the eNodeB.

  The program that operates in the apparatus according to the present invention may be a program that controls a central processing unit (CPU) or the like to cause a computer to function so as to realize the functions of the above-described embodiments according to the present invention. At the time of processing, the program or information handled by the program is temporarily read into volatile memory such as Random Access Memory (RAM), or stored in nonvolatile memory such as flash memory or Hard Disk Drive (HDD). In response, the CPU reads, corrects and writes.

  A part of the device in the above-described embodiment may be realized by a computer. In that case, a program for realizing the control function may be recorded in a computer readable recording medium, and the computer system may read and execute the program recorded in the recording medium. The "computer system" referred to here is a computer system built in an apparatus, and includes hardware such as an operating system and peripheral devices. The “computer-readable recording medium” may be any of a semiconductor recording medium, an optical recording medium, a magnetic recording medium, and the like.

  Furthermore, "a computer-readable recording medium" is one that holds a program dynamically for a short time, like a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case may also include one that holds a program for a certain period of time. The program may be for realizing a part of the functions described above, or may be realized in combination with the program already recorded in the computer system.

  In addition, each functional block or feature of the device used in the above-described embodiment may be implemented or implemented in an electric circuit, that is, typically an integrated circuit or a plurality of integrated circuits. Electrical circuits designed to perform the functions described herein may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or the like. Programmable logic devices, discrete gates or transistor logic, discrete hardware components, or combinations thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be a conventional processor, controller, microcontroller, or state machine. The general purpose processor or each of the circuits described above may be composed of digital circuits or may be composed of analog circuits. In addition, when advances in semiconductor technology give rise to integrated circuit technology that replaces current integrated circuits, integrated circuits according to such technology can also be used.

  The present invention is not limited to the above embodiment. Although an example of the device has been described in the embodiment, the present invention is not limited thereto, and a stationary or non-movable electronic device installed indoors and outdoors, for example, an AV device, a kitchen device, The present invention can be applied to terminal devices or communication devices such as cleaning and washing equipment, air conditioners, office equipment, vending machines, and other household appliances.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope of the present invention are also included. Furthermore, the present invention can be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means respectively disclosed in different embodiments are also included in the technical scope of the present invention. Be Moreover, it is an element described in each said embodiment, and the structure which substituted the elements which show the same effect is also contained.

2 (2A, 2B, 2C) Terminal device 3 (3A, 3B) Base station device 20, 30 Wireless transmitting / receiving unit 21, 31 Antenna unit 22, 32 RF unit 23, 33 Base band unit 24, 34 Upper layer processing unit 25, 35 Medium Access Control Layer Processing Unit 26, 36 Wireless Resource Control Layer Processing Unit

Claims (6)

A terminal apparatus that communicates with a base station apparatus via a cell,
Receiving from the base station apparatus a handover command instructing handover to a second cell in the first cell;
Radio resource control (RRC) re-establishment is considered as radio link failure if the second timer is counting or expired when the first timer expires, and the first timer expires If the second timer is not clocking or has not expired, it is not considered as a radio link failure and radio resource control (RRC) reestablishment is not performed, and the first timer starts clocking when a handover command is received. The timer is a timer, and the second timer starts counting when a predetermined number of consecutive out-of-sync conditions in the first cell are detected a predetermined number of times, and continuously detects a predetermined number of synchronized conditions in the first cell. A terminal device characterized by being a timer that stops timing. The second timer further stops clocking after receiving the handover command when the handover is a handover in which communication with the first cell is not continued after receiving the handover command. The terminal device according to claim 1, wherein timing is continued if the handover is a handover in which communication with the first cell is continued after receiving the handover command. The second timer performs clocking after receiving the handover command when the handover is a handover in which communication with the first cell is continued even after receiving the handover command. The terminal device according to claim 1. A base station apparatus that communicates with a terminal apparatus;
Transmitting a handover command instructing the handover from the first cell to the second cell to the terminal device;
In the case where the handover command includes a value to be set to the first timer in the handover command, in the terminal device, the handover is such that the handover continues communication with the first cell even after receiving the handover command. A base station apparatus used to determine a radio link failure in a first cell. An integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell,
A function of receiving from the base station apparatus a handover command instructing handover to a second cell in a first cell;
The function of performing radio resource control (RRC) reestablishment as radio link failure when the second timer is counting or expiring when the first timer expires, and the first timer has expired At the same time, when the second timer is not counting time or is not expired, the terminal device is made to exhibit the function of not performing radio resource control (RRC) re-establishment without regard to radio link failure and causing the terminal device to perform the first The timer is a timer that starts clocking when a handover command is received, and the second timer starts clocking when a predetermined number of consecutive out-of-sync conditions in the first cell are detected. An integrated circuit characterized by being a timer which stops clocking when a predetermined number of consecutive synchronization states in a cell are detected. An integrated circuit mounted on a terminal apparatus that communicates with a base station apparatus via a cell,
Receiving from the base station apparatus a handover command instructing handover to a second cell in a first cell;
Radio resource control (RRC) re-establishment is considered as radio link failure if the second timer is counting or expired when the first timer expires, and the first timer expires The wireless resource control (RRC) is not considered to be a radio link failure if the second timer is not counting time or is not expired, and at least the step of not performing radio resource control (RRC) reestablishment, the first timer receiving a handover command The second timer starts counting when a predetermined number of consecutive out-of-sync conditions in the first cell are detected for a predetermined number of times, and the second timer continues to synchronize in the first cell. A communication method characterized in that it is a timer that stops clocking when it is detected a predetermined number of times.

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