KR102204897B1 - Method and apparatus for performing carrier aggregation handover - Google Patents

Abstract

The present invention relates to a method and apparatus for performing handover of a CA (Carrier Aggregation) terminal, wherein the method of the base station for controlling the handover of the terminal includes a terminal in a first cell and a second carrier frequency corresponding to a first carrier frequency. A process of determining whether to use a corresponding second cell at the same time, and a process of controlling the handover of the terminal using a measurement configuration set corresponding to the determination result among a plurality of measurement configuration sets preset for each handover-related event. Including, by always maintaining a good channel state of the P cell, there is an effect of ensuring higher data transmission and reception efficiency than a non-CA terminal.

Description

A method and apparatus for performing handover of a carrier aggregation terminal TECHNICAL FIELD [METHOD AND APPARATUS FOR PERFORMING CARRIER AGGREGATION HANDOVER]

The present invention relates to a method and apparatus for performing handover of a CA (Carrier Aggregation) terminal.

As mobile terminals become popular, data traffic is rapidly increasing. Recently, in order to support rapidly increasing data traffic, a CA terminal using a primary cell and a secondary cell using different carrier frequencies has been provided, and CA is a terminal with a lot of data traffic. It is a suitable service. In particular, Release 10 TS36.300 Annex. J introduces various scenarios applicable to CA terminals.

As an example, a co-located scenario has been proposed in which the frequency domains of P cells and S cells are overlapped to maximize data throughput. However, it is only an ideal scenario that the frequency domains of the P cell and the S cell coincide, and in reality, it is difficult for the P cell and the S cell to be perfectly matched. If a lot of time is required to match the areas of the mismatched P cell and S cell, even if a lot of time is invested to adjust the areas of the P cell and S cell, it is almost impossible to physically match the two areas perfectly. .

If the frequency domains of the Pcell and Scell do not match each other, a terminal supporting CA receives a weaker signal than a non-CA terminal that does not support CA, and the data throughput of the terminal supporting CA is non-CA. There may be a situation where the data throughput of the terminal is lowered. For example, as shown in FIG. 1, in a situation in which the frequency domain is inconsistent, the CA terminal may use the P1 cell as the P cell and the B cell as the S cell. At this time, the P cell and the S cell may be pre-matched in the form of P0 and A, P1 and B, and P2 and C according to a co-located scenario. In the illustrated location, the CA terminal is in a state in which it is almost impossible to receive signals from cell B, which is an S cell, but does not perform handover because the strength of signal reception from cell P1, which is a P cell, is not necessarily weak enough to perform handover. Does not. That is, the CA terminal in the illustrated location cannot receive a signal from cell B when the new location reception state of the P1 cell is not very good, whereas a terminal that does not support CA at the same location accesses cell C and transmits a strong signal. Can receive. As a result, a situation in which the signal transmission/reception efficiency is not good may occur in the terminal supporting the CA compared to the terminal not supporting the CA.

Accordingly, there is a need to provide a technology that enables a CA terminal using both a P cell and an S cell to more quickly handover to a cell having a good channel condition, thereby increasing data transmission efficiency at all times than a terminal that does not support CA.

Accordingly, an embodiment of the present invention is to provide a method and apparatus for performing handover in consideration of both channel conditions of the currently accessed Pcell and Scell in a CA terminal using both a Pcell and an Scell.

According to an embodiment of the present invention, even if the CA terminal using both the Pcell and the Scell does not satisfy the handover event condition defined in the existing handover standard under the heavy electric field of the currently connected Pcell, the Scell frequency domain It is to provide a method and apparatus for performing handover to another cell having a better channel condition than my Pcell.

Another embodiment of the present invention is to provide a method and apparatus for additionally configuring a measurement report set for handover of a CA terminal for each handover-related event in a base station.

According to an embodiment of the present invention, a method of a base station for controlling a handover of a terminal in a carrier aggregation (CA) system includes a first cell corresponding to a first carrier frequency and a second cell corresponding to a second carrier frequency. Determining whether to use at the same time, and controlling handover of the terminal using a measurement configuration set corresponding to a determination result among a plurality of measurement configuration sets preset for each handover-related event.

According to an embodiment of the present invention, a method of a terminal for controlling a handover of a terminal in a carrier aggregation (CA) system, wherein the terminal is a first cell corresponding to a first carrier frequency and a first cell corresponding to a second carrier frequency. 2 A process of receiving a measurement configuration set according to whether or not a cell is simultaneously used, and a process of detecting and reporting whether a corresponding handover-related event occurs based on the measurement configuration set.

According to an embodiment of the present invention, an apparatus of a base station for controlling a handover of a terminal in a CA (Carrier Aggregation) system includes a transceiver for transmitting and receiving a signal with the terminal, and a plurality of preset measurement configuration sets for each handover-related event. A storage unit that stores and determines whether the terminal simultaneously uses the first cell corresponding to the first carrier frequency and the second cell corresponding to the second carrier frequency, and a plurality of measurement configurations preset for each handover-related event It includes a control unit for controlling the handover of the terminal by using a measurement configuration set corresponding to the determination result among the three.

According to an embodiment of the present invention, an apparatus of a terminal for controlling a handover of a terminal in a carrier aggregation (CA) system includes a transceiver for transmitting and receiving a signal, and a first cell corresponding to a first carrier frequency and A control unit that receives a measurement configuration set according to whether or not a second cell corresponding to a second carrier frequency is simultaneously used, and controls a function to detect and report whether a corresponding handover-related event occurs based on the measurement configuration set Includes.

In the present invention, even if the CA terminal using both the Pcell and the Scell does not satisfy the conditions of the handover event defined in the existing handover standard in a situation below the heavy electric field of the currently connected Pcell, the channel situation than the Pcell By performing a handover to another cell in this good Scell frequency domain, there is an effect of ensuring higher data transmission/reception efficiency than a non-CA terminal by always maintaining a good channel state of the Pcell.

1 is a diagram illustrating a handover situation according to a location of a terminal supporting CA according to an embodiment of the present invention;
2 is a diagram showing a block configuration of a base station for controlling handover of a terminal supporting CA according to an embodiment of the present invention;
3 is a diagram illustrating a block configuration of a terminal supporting CA according to an embodiment of the present invention;
4A and 4B are diagrams illustrating a handover control procedure of a terminal in a base station according to an embodiment of the present invention.
5A and 5B are diagrams illustrating an operation procedure for handover in a terminal according to an embodiment of the present invention.
6A and 6B are diagrams illustrating a handover control procedure of a terminal in a base station according to another embodiment of the present invention, and
7 is a diagram illustrating an operation procedure for handover in a terminal according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Further, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter, a method and apparatus for performing handover of a carrier aggregation (CA) terminal will be described. Here, the CA terminal refers to a user terminal that simultaneously uses a P cell and an S cell using different carrier frequencies. For example, as illustrated in FIG. 1, it may mean a user terminal that simultaneously uses cell P0 and cell A using different carrier frequencies, or cell P1 and cell B.

According to an embodiment of the present invention, in order to improve the data transmission/reception throughput of a terminal supporting CA, a terminal supporting CA is handed to another cell in the S cell frequency domain with a better channel condition in a situation below the heavy electric field of the P cell. Handle it so that it can be over. To this end, in an embodiment of the present invention, while using the measurement configuration sets (or measurement conditions) for handover-related events and handover-related events defined in the conventional handover standard, each event A measurement configuration set for the CA terminal is additionally set. For example, in the prior art, in order to detect the occurrence of each of the handover-related events A1, A2, A3, and A5, one set of measurement configurations for each handover-related event existed, but in the embodiment of the present invention, the handover-related event A1 Set up an additional set of measurement configurations to detect A2, A3 and A5 respectively. In other words, in an embodiment of the present invention, a plurality of measurement configuration sets may be set for each event. Here, the measurement configuration set may include measurement identification information (measurement ID), and the measurement identification information includes a measurement object ID (ID) indicating information on a frequency to be measured and a corresponding event and threshold and/or threshold. It is configured to include a report configuration ID indicating offset information. In addition, event A1 is generated when the signal strength of the serving cell is greater than the threshold included in the A1 measurement configuration set, Event A2 is generated when the signal of the serving cell is less than the threshold included in the A2 measurement configuration set, and A3 is Occurs when the signal of the adjacent cell is greater than the signal of the serving cell by the threshold offset value included in the A3 measurement configuration set, and event A5 is the signal of the serving cell is less than the first threshold value included in the A5 measurement configuration set, and the adjacent cell It may be generated when the signal of is greater than the second threshold included in the A5 measurement configuration set. In an embodiment of the present invention, the handover-related event means including a measurement report-related event, and in the following description, the handover-related event may be described as a measurement report-related event or event.

As described above, in the embodiment of the present invention, a plurality of measurement configuration sets may be set for each measurement report-related event. For example, two measurement configuration sets are provided for event A2 as shown in Tables 1 and 2 below. Can be set. In the following description, in order to distinguish between an event generated by a conventional measurement configuration set and an event generated by a measurement configuration set additionally set for a CA terminal according to an embodiment of the present invention, The event is denoted as "A#", and the event generated by the measurement configuration set for the CA terminal is denoted as "A#(CA)".

Table 1 below shows a set of measurement configurations for event A2, and Table 2 below shows a set of measurement configurations for event A2 (CA).

measurement id(MeasId) 100 measurement object id(measObjectId) 200 measObjectEUTRA
carrierFreq:800MHz
: report config id (report ConfigId) 300 reportConfigEUTRA
eventA2
threshold-RSRP: 1000
threshold-RSRQ: 2000

measurement id(MeasId) 110 measurement object id(measObjectId) 200 measObjectEUTRA
carrierFreq:800MHz
: report config id (report ConfigId) 310 reportConfigEUTRA
eventA2
threshold-RSRP: 3000
threshold-RSRQ: 4000

Looking at Tables 1 and 2, it is indicated that the frequency corresponding to 800MHz should be measured for both of the two measurement configurations. In addition, when both Tables 1 and 2 satisfy the corresponding threshold, it indicates that event A2 occurs. However, for event A2 in Table 1, the threshold for the received signal strength is 1000 and the threshold for the received signal quality is 2000, and for Event A2 (CA) in Table 2, the threshold for the received signal strength is 3000, and the received signal. The threshold for quality is 4000. That is, the event A2 and the event A2 (CA) only have different threshold values, and mean substantially the same measurement report-related event A2.

The relationship between the threshold value and the offset value included in the measurement configuration set of event A# and event A# (CA) is shown in Table 3 below.

Event type Threshold relationship Event A1: Serving becomes better than absolute threshold Threshold_CA> Threshold_Legacy Event A2: Serving becomes worse than absolute threshold Threshold_CA> Threshold_Legacy Event A3: Neighbor becomes amount of offset better than PCell Offset_CA >= offset_Legacy Event A5: PCell becomes worse than absolute threshold1 AND Neighbor better than another absolute threshold2 A5 Threshold1_CA> A5 Threshold1_Legacy
A5 Threshold2_CA> A5 Threshold2_Legacy

As shown in Table 3, the threshold and offset of the event A# (CA) according to an embodiment of the present invention are set to a value greater than or equal to the threshold and offset of the corresponding conventional event A#. This is because the conventional terminal detects the occurrence of a measurement report-related event in a situation in which the P cell is in a weak electric field, reports it to the base station, and performs handover, but in an embodiment of the present invention, the CA terminal This is to ensure that the channel quality for the P cell is always maintained above a certain level by detecting the occurrence of a measurement report-related event in the following situations, and reporting it to the base station to handover.

In addition, according to an embodiment of the present invention, the CA terminal handovers over to another neighboring cell in the Scell frequency domain having a better channel state than the Pcell channel state in a situation where the channel state from the Pcell is less than a certain level, Data transmission and reception efficiency of the CA terminal can be maintained above a certain level.

In addition, according to an embodiment of the present invention, an event related to a measurement report is defined to detect a situation in which the addition or release of an S cell occurs, and to report it. For example, when the CA terminal detects the release of the S cell, the terminal reports the event A2 (S) to the base station, and when the CA terminal detects an additional situation of the S cell, the terminal sends the event A4 (S ) To report to the base station. According to an embodiment, the measurement configuration set of event A2(S) may include a measurement target ID indicating a carrier of the S cell as a measurement target and a threshold value for determining a threshold for termination of the S cell, and event A4 The measurement configuration set of (S) may include a measurement object ID indicating a carrier of the S cell as a measurement object, and a threshold value for determining a threshold value for addition of the S cell.

Then, with reference to FIGS. 2 to 7 below, a method and apparatus for handling handover of a CA terminal based on a plurality of measurement configuration sets for each measurement report-related event will be described in detail as described above. .

2 is a block diagram of a base station for controlling a handover of a terminal supporting CA in a CA system according to an embodiment of the present invention.

Referring to FIG. 2, the base station 200 may include a transceiver 201, a control unit 203, and a storage unit 205.

The transmission/reception unit 201 controls and processes a function for transmitting/receiving signals to and from the terminal under the control of the control unit 201. Specifically, the transmission/reception unit 201 transmits a message (eg, a radio resource control (RRC) connection reconfiguration message) including a set of measurement conditions for a specific measurement report-related event to the terminal under the control of the control unit 201, A function for receiving a specific measurement report-related event occurrence report message from the corresponding terminal may be processed. In addition, the transmission/reception unit 201 may include a Pcell transmission/reception module for communication using a first carrier frequency and an Scell transmission/reception module for communication using a second carrier frequency. In addition, although the transmission/reception unit 201 is configured as one module, it may be separately configured as a transmission/reception unit and a reception unit according to a design method.

The controller 203 controls and processes the overall operation of the base station 200 for providing a service to the terminal. In particular, the control unit 203 according to an embodiment of the present invention includes the handover control unit 207 to control and process a function for controlling handover between a CA terminal and a non-CA terminal. That is, the handover control unit 207 determines whether the terminal is a CA terminal using Pcell and Scell at the same time or a non-CA terminal using only one serving cell (eg, Pcell), and determines whether the terminal is a CA terminal or a non-CA terminal. -Set a measurement configuration set for a measurement report-related event based on whether it is a CA terminal, and control and process a function for transmitting a message including the set measurement configuration set. For example, the handover control unit 207 may receive cell information currently in use from a terminal connected to the base station 200 and check whether the corresponding terminal is a terminal supporting CA.

In addition, the handover control unit 207 detects the occurrence of a measurement report-related event based on the measurement report message received from the corresponding terminal, and processes the handover of the corresponding terminal according to the generated measurement report-related event, or performs a corresponding measurement report-related event. Controls and processes the function to clear the setting of the measurement configuration set for and send a message to set the measurement configuration set for other measurement report related events. For example, in the case of a CA terminal using a P cell and an S cell at the same time, the handover control unit 207 sets and transmits a measurement report set for event A2 (CA), and supports only one serving cell. In the case of a terminal, it controls and processes a function for setting and transmitting a measurement report set for event A2. Additionally, the handover control unit 207 sets and transmits a measurement report set for event A2(S) in case of a CA terminal using Pcell and Scell at the same time, and when the Scell is released from the terminal, A2(S) In the case of a non-CA terminal that reports that an event has occurred and supports only one serving cell, when an S cell is added from the terminal by setting and transmitting a measurement report set for event A4 (S), event A4 (S ) Can be controlled and processed to report that an event has occurred.

For example, for the handover control of the CA terminal, the handover control unit 207 first configures an RRC connection including a measurement configuration set for events A2 (CA) and A2 (S). Reconfiguration) message can be transmitted to the CA terminal. In this case, the measurement configuration set may include measurement frequency information and a threshold value for an event related to a corresponding measurement report. The measurement frequency information included in the measurement configuration set for event A2 (CA) according to an embodiment of the present invention may be set as the carrier frequency of the P cell to which the corresponding CA terminal is connected, and the measurement configuration for event A2(S) The measurement frequency information included in the set may be set as the carrier frequency of the S cell to which the corresponding CA terminal is connected. When a measurement report message indicating that the event A2 (CA) has occurred from the corresponding CA terminal is received, the handover control unit 207 commands the setting of the measurement configuration set of the event A2 (CA) to be canceled, and the event A1 (CA), An RRC message including a set of measurement conditions for each of A3 (CA) and A2 may be transmitted to the CA terminal. For example, when the event A2 (CA) is reported from the CA terminal, the handover control unit 207 determines that the corresponding CA terminal is below the P cell's heavy electric field and satisfies the handover condition below the P cell's heavy electric field. A set of measurement conditions for event A3 (CA) to check whether another cell is present, a set of measurement conditions for event A1 (CA) to detect a situation in which the corresponding CA terminal moves back to the strong electric field of the P cell, In order to detect a situation in which the corresponding CA terminal moves to the weak electric field of the P cell, it is possible to control and process a function for setting and transmitting a set of measurement conditions for event A2. If, when an event A1 (CA) is reported from the CA terminal, the handover control unit 207 determines that the CA terminal is moved to the strong electric field of the P cell and does not require handover, and events A1 (CA), A3 A message for setting the measurement condition set for event A2 (CA) can be transmitted and processed again after releasing the setting of the measurement configuration set for (CA) and A2. On the other hand, when an event A3 (CA) is reported from the CA terminal, the handover control unit 207 determines that the CA terminal has found an adjacent cell having a signal strength greater than the threshold value higher than the P cell in the S cell frequency domain, and the event A3 (CA), A1 (CA), A2 (S), it is possible to control and process a function for canceling the setting of the measurement configuration set for A2 and handing over the CA terminal to an adjacent cell. On the other hand, when the event A2 is reported from the CA terminal, the handover control unit 207 does not have an adjacent cell with a better channel condition than the P cell when the CA terminal is below the heavy electric field of the P cell, and the CA terminal is weakened. It detects that it has moved to the system and sends a message to clear the measurement configuration set for events A1(CA), A3(CA), A2(S), and A2, and to set the measurement configuration set for the A3 event and A1 event. You can handle it. On the other hand, when a measurement report message indicating that the event A2(S) has occurred is received, it is determined that the corresponding CA terminal has been changed to a non-CA terminal supporting only one serving cell (eg, P cell), and event A3 (CA ), A1(CA), A2(S), while commanding to cancel the setting of the measurement configuration set, measurement report for A2 event and measurement report for event A4(S) to detect additional situation of S cell The RRC message including the set can be transmitted to the corresponding non-CA terminal.

In another embodiment, when a measurement report message indicating that the event A2 (S) has occurred from the corresponding CA terminal is received, the handover control unit 207 cancels the setting of the measurement configuration set of the events A2 (CA) and A2 (S). While commanding, an RRC message including a set of measurement conditions for each of events A2 and A4(S) may be transmitted to the CA terminal. For example, when the handover control unit 207 receives a measurement report message indicating that the event A2(S) has occurred from the corresponding CA terminal, the corresponding CA terminal supports only one serving cell (eg, P cell). It is determined that it has been changed to the terminal, and an RRC message including a measurement report set for an event A4(S) for detecting an additional situation of an S cell can be transmitted to the corresponding non-CA terminal together with a measurement report set for the A2 event. have.

When a measurement report message indicating that event A2 has occurred from the corresponding non-CA terminal is received, the handover control unit 207 commands the setting of the measurement configuration set of events A2 and A4(S) to be canceled, and the corresponding non-CA terminal Setting and transmitting a set of measurement conditions for event A1 to detect the movement to the strong electric field of this P cell and event A3 to check whether another cell that satisfies the handover condition exists in the weak electric field of the P cell. You can control and process functions for. When the event A1 is reported from the non-CA terminal, the handover control unit 207 determines that the non-CA terminal moves to the strong electric field of the P cell and does not require handover, and measures events A1 and A3. It is possible to release the setting of the set and transmit a message for setting the measurement configuration set for events A2 and A4(S) again. On the other hand, the handover control unit 207 when an event A3 is reported from the corresponding non-CA terminal. , It is determined that the corresponding non-CA terminal has found an adjacent cell whose signal strength is better than the P cell by a threshold value or more, and releases the setting of the measurement configuration set for events A1 and A3, and the corresponding non-CA terminal as the found adjacent cell. You can control and process functions for handing over. On the other hand, when a measurement report message indicating that an event A4(S) has occurred from the corresponding non-CA terminal is received, the handover control unit 207 sends the non-CA terminal to a CA terminal supporting both the Pcell and the Scell. Event A2(S) to determine the change, release the setting of the measurement configuration set for events A2 and A4(S), and detect the release status of the S cell along with the measurement report set for the A2(CA) event An RRC message including a measurement report set for can be transmitted to the corresponding CA terminal.

For another example, the handover control unit 207 includes a set of measurement conditions for each of events A5 (CA), A2 (S), and A2 when the corresponding terminal is a CA terminal that simultaneously uses a P cell and an S cell. The RRC message can be transmitted to the CA terminal. For example, the handover control unit 207 detects a set of measurement conditions for event A5 (CA) and a release condition of the S cell in order to check whether another cell that satisfies the handover condition exists below the heavy electric field of the P cell. It is possible to control and process a function for setting and transmitting a set of measurement conditions for the event A2(S) and a set of measurement conditions for the event A2 to detect a situation in which the corresponding CA terminal moves to the weak electric field of the P cell. . If, when event A5 (CA) is reported from the CA terminal, the handover control unit 207 determines that the CA terminal has a signal reception strength from the S cell less than the threshold value and the signal reception strength from the adjacent cell is better than the threshold value. It is determined that it is determined, and the setting for events A5 (CA), A2, and A2 (S) is released, and a function for handing the CA terminal to an adjacent cell can be controlled and processed. On the other hand, when event A2(S) is reported from the CA terminal, the handover control unit 207 determines that the S cell of the CA terminal is released and the CA terminal is changed to a non-CA terminal, and events A2 (S) and A5 Controls and processes functions for canceling the setting for (CA), maintaining the setting for A2, and additionally setting an event for A4(S). When event A2 is reported from the CA terminal, the handover control unit 207 indicates that when the CA terminal is in the heavy electric field of the P cell, there was no adjacent cell with a better channel condition than the P cell, and the CA terminal moved to the weak electric field. Controls and processes functions to detect, clear the setting of the measurement configuration set for events A5 (CA), A2 (S) and A2, and set the measurement configuration set for events A5 and A1.

On the other hand, when the corresponding terminal is a non-CA terminal using only the P cell as a serving cell, the handover controller 207 may transmit an RRC message including a set of measurement conditions for each of the events A2 and A4(S) to the CA terminal. . For example, the handover control unit 207 responds to a set of measurement conditions for event A2 and an event A4(S) for detecting an additional situation of the S cell in order to detect a situation in which the corresponding non-CA terminal moves to the weak electric field of the P cell. It can control and process functions for setting and transmitting a set of measurement conditions for. If, when event A4(S) is reported from the non-CA terminal, the handover control unit 207 determines that the S cell is added to the non-CA terminal and is changed to the CA terminal, and the event A2 and A4(S) Controls and processes the function for canceling the setting for A5 (CA), setting and transmitting the measurement condition set for each of A5 (CA), A2 (S) and A2. On the other hand, when event A2 is reported from the non-CA terminal, the handover control unit 207 releases the settings for events A2 and A4(S), and other Pcells satisfying the handover condition in the weak electric field of the Pcell. Controls and processes a function for setting and transmitting a measurement report set for event A5 to check whether or not there is, and a measurement report set for event A1 to detect a movement to the strong electric field of cell P. If, when event A5 is reported from the corresponding non-CA terminal, the handover controller 207 releases the settings for events A5 and A1, and handovers the corresponding non-CA terminal to another Pcell satisfying the handover condition. It controls and processes the function to make it. On the other hand, when event A1 is reported from the corresponding non-CA terminal, the handover control unit 207 releases settings for events A5 and A1, and detects a situation in which the corresponding non-CA terminal moves to the weak electric field of the Pcell. For this purpose, it controls and processes the function to set the measurement condition set for event A2 and the measurement condition set for event A4(S) to detect the additional situation of S cell.

The storage unit 205 may store various data and programs required for the operation of the base station. According to an embodiment of the present invention, the storage unit 205 may store information on a measurement configuration set for each event related to handover, that is, a measurement report related event. For example, the storage unit 205 may store two measurement configuration sets as shown in Tables 1 and 2 for the measurement report-related event A2. Here, the threshold value and/or offset included in the measurement configuration set of event A# (CA) has a value greater than or equal to the threshold value and/or offset value included in the measurement configuration set of the corresponding event A#. Further, according to an embodiment of the present invention, measurement frequency information included in the measurement configuration set of events A3 (CA) and A5 (CA) may be set as a carrier frequency of the S cell. In addition, the storage unit 205 may store information indicating whether the connected terminal is a CA terminal using a P cell and an S cell at the same time or a non-CA terminal using only the P cell as a serving cell. In addition, the storage unit 205 may include a set of measurement configurations for events A2(S) and A4(S) for detecting an S cell release and an additional situation of the terminal. According to an embodiment, the measurement configuration set of each of the events A2(S) and A4(S) may include at least one of a measurement object ID and a threshold value.

3 is a block diagram of a terminal supporting CA in a CA system according to an embodiment of the present invention.

Referring to FIG. 3, the base station 300 may include a transceiver 301, a control unit 303 and a storage unit 305.

The transmission/reception unit 301 controls and processes functions for transmitting and receiving signals to and from the base station under the control of the control unit 301. Specifically, the transceiver 301 receives a message (eg, a radio resource control (RRC) connection reconfiguration message) including a set of measurement conditions for a specific measurement report-related event from the base station under the control of the controller 301, A function for transmitting a message (eg, a measurement report message) reporting that a specific measurement report-related event occurs can be handled. In addition, the transmission/reception unit 301 may include a P-cell transmission/reception module for communication using a first carrier frequency and an S-cell transmission/reception module for communication using a second carrier frequency. In addition, although the transmission/reception unit 301 is configured as a single module, it may be separately configured as a transmission/reception unit and a reception unit according to a design method.

The controller 303 controls and processes the overall operation of the terminal 300 for receiving communication service from the base station 200. In particular, the control unit 303 according to an embodiment of the present invention, including the handover control unit 307, checks a measurement configuration set for a measurement report-related event from a message received from the base station 200, and It determines whether a measurement report-related event occurs based on the included conditions, and when a specific measurement report-related event occurs, controls and processes a function for reporting to the base station 200 that a corresponding measurement report-related event has occurred. For example, the handover control unit 307 checks a measurement configuration set for a specific measurement report-related event from the RRC connection reconfiguration message, and checks measurement frequency information and threshold or offset information in the measurement configuration set. Thereafter, the handover control unit 307 measures the signal reception strength and/or the signal reception quality for the corresponding frequency information, and determines whether the condition of the corresponding measurement report-related event is satisfied by comparing the measured value and the threshold value. I can. Here, the measurement frequency information may indicate the carrier frequency of the P cell or the carrier frequency of the S cell. The handover control unit 307 measures the signal reception strength and/or signal reception quality for the corresponding frequency information, measures the signal reception strength and/or signal reception quality for the adjacent cell, and compares the measured values with the threshold value. Alternatively, it is possible to determine whether an event related to the corresponding measurement report has occurred by checking whether a value measured for the corresponding frequency information and a value measured for an adjacent cell differ by an offset value. When a specific measurement report-related event occurs, the handover control unit 307 reports to the base station 200 that the corresponding measurement report-related event has occurred, and releases the setting of the measurement configuration set received through the previous RRC connection reconfiguration message, An RRC connection reconfiguration message including a measurement configuration set for a measurement report-related event may be received, or a message instructing a handover to an adjacent cell may be received.

The storage unit 305 may store various data and programs required for the operation of the terminal. According to an embodiment of the present invention, the storage unit 205 may store information on a measurement configuration set of a measurement report-related event received through an RRC connection reconfiguration message from a base station. In addition, when it is requested to release the setting of the measurement configuration set of a specific measurement report-related event through an RRC connection reconfiguration message from the base station, information on the measurement configuration set may be deleted.

4A and 4B are diagrams illustrating a handover control procedure of a terminal in a base station according to an embodiment of the present invention.

4A and 4B, in step 401, the base station checks whether the UE uses the Pcell and the Scell at the same time. For example, the base station may receive information about the cell currently being used from the terminal, and determine whether the corresponding terminal is a CA terminal using both a Pcell and an Scell, or a non-CA terminal using only the Pcell as a serving cell.

When the terminal uses the P cell and the S cell at the same time, the base station sets the A2 (S) event in step 403 and the A2 (CA) event in step 405, and proceeds to step 407 to proceed with the A2 (CA) event and A ( S) Check whether any one of the events occurs. For example, as shown in Table 2, the base station sends an RRC connection reconfiguration message including a set of measurement configurations for an A2 (CA) event and a set of measurement configurations for an A2 (S) event for the release situation of the S cell to the terminal. By transmitting, the terminal sets up a set of measurement configurations indicating conditions for detecting the occurrence of an A2 (CA) event or an A2 (S) event, and any one of the A2 (CA) event and A2 (S) event from the terminal It checks whether a measurement report message reporting that an event has occurred is received.

When the A2 (CA) event occurs in the terminal, the base station sets the A3 (CA) event, the A1 (CA) event, and the A2 event in step 409, and releases the setting of the A2 (CA) event. For example, the base station includes a measurement configuration set for each of the A3 (CA) event, A1 (CA) event, and A2 event, and sends an RRC connection reconfiguration message requesting release of the measurement configuration set of the A2 (CA) event. Can be transmitted to the terminal. At this time, the measurement configuration sets of the A3 (CA) event, the A1 (CA) event, and the A2 event use the carrier frequency of the P cell as a measurement target.

Thereafter, in steps 411, 413, and 420, the base station checks whether any of the A3 (CA) events, A1 (CA) events, A2 (S) events, and A2 events occur. The base station checks whether any of the A3 (CA) event, A1 (CA) event, A2 (S) event, and A2 event occurs through the measurement report message received from the terminal through steps 411, 413 and 420. I can. In the drawing, the step of examining which event occurs among the A3 (CA) event, A1 (CA) event, A2 (S) event, and A2 event by the base station is described in steps 411, 413 and 420 for convenience of the city. Although shown separately, it is natural that it can be composed of one step.

If it is confirmed that the A3 (CA) event has occurred, the base station releases the settings of the A3 (CA) event, A1 (CA) event, A2 (S) event, and A2 event in step 415, and the terminal A handover is determined using the adjacent cell reported from the target P cell. For example, when the occurrence of an A3 (CA) event is reported from the terminal, the base station receives signals from adjacent cells in the S cell frequency domain when the terminal is located below the Pcell's heavy electric field. Since the reception is greater than the offset value than the reception strength, it is predicted that the data transmission/reception efficiency of the terminal can be improved to a certain level or more when handing over to a corresponding adjacent cell, and it is determined to handover the terminal to the corresponding adjacent cell. In this case, the UE performs handover using an adjacent cell as a P cell under the control of the base station, and when the S cell exists and is available, the P cell and the S cell may be used together.

On the other hand, when it is determined that the A1 (CA) event has occurred, the base station releases the settings of the A3 (CA) event, A1 (CA) event, and A2 event in step 419, and returns to step 405. That is, when an A1 (CA) event is detected from the terminal, the base station determines that the handover is not necessary because A1 (CA) is located in the strong electric field of the P cell, and can set the A2 (CA) event again. have.

On the other hand, when it is confirmed that the A2 event has occurred, the base station releases the settings of the A3 (CA) event, A1 (CA) event, A2 (S) event, and A2 event in step 421, and the P cell is weakened in step 433. In the electric field, an A3 event to detect whether there is another P cell that is received with a size greater than the threshold offset value than the signal of the P cell and an A1 event to detect the movement to the strong electric field of the P cell are set, and proceed to step 435. do.

On the other hand, when it is confirmed that the A2(S) event has occurred, the base station cancels the settings of the A3(CA) event, A1(CA) event, and A2(S) event in step 423, and adds the S cell in step 427. The A4(S) event for detecting the situation is set, and the process proceeds to step 429 below.

On the other hand, as a result of the examination in step 407, when an A2 (S0 event occurs in the terminal, the base station determines that the terminal is changed to a terminal using only the P cell as a serving cell, and in step 424, the A2(S) event, A2(CA) event) Release the setting of and proceed to step 425 below.

As a result of the check in step 401, when the terminal uses the P cell as a serving cell, an A2 event and an A4(S) event are set. For example, the base station sets an A2 event to detect movement to the weak electric field of the P cell in step 425, sets an A4(S) event to detect an additional situation of the S cell in step 427, and proceeds to step 429 to the terminal. Check whether the A2 event occurs in For example, the base station transmits an RRC connection reconfiguration message including a measurement configuration set for an A2 event to the terminal as shown in Table 1, and sets a measurement configuration set indicating a condition for the terminal to detect the occurrence of an A2 event. Then, it is checked whether a measurement report message reporting that an A2 event has occurred from the terminal is received.

If the A2 event occurs in the terminal, the base station releases the configuration of the A2 event and the A4(S) event in step 431, and sets the A3 event and A1 event. For example, the base station may include a measurement configuration set for each of the A3 event and the A1 event, and may transmit an RRC connection reconfiguration message requesting release of the configuration set of the A2 event to the terminal. At this time, the measurement configuration set of the A1 and A3 events is the carrier frequency of the P cell (or the cell to which the terminal is connected) as a measurement target.

Thereafter, the base station proceeds to step 433 and checks whether an event occurs among the A3 event and the A1 event. The base station may check whether an event occurs among the A3 event and the A1 event through the measurement report message received from the terminal. If it is determined that the A3 event has occurred, the base station releases the configuration of the A3 event and the A1 event in step 437, and determines a handover using the adjacent cell reported from the terminal as the target P cell in step 439. On the other hand, when it is determined that the A1 event has occurred, the base station releases the settings of the A3 event and the A1 event in step 441, and returns to step 401.

If, when the terminal reports the occurrence of the A4(S) event, the base station releases the setting of the A2 event and the A4(S) event in step 443, and returns to step 401.

5A and 5B illustrate an operation procedure for handover in a terminal according to an embodiment of the present invention.

5A and 5B, the UE checks whether a specific measurement report event condition, that is, a measurement configuration set for a measurement report event, is received from the base station in step 501. For example, the terminal checks whether the RRC connection reconfiguration message received from the base station includes a measurement condition for a specific measurement report-related event, that is, a measurement configuration set.

When the conditions for the A2(CA) and A2(S) events are received from the base station, the terminal checks the measurement target frequency and threshold value from the measurement configuration set of the A2(CA) event in step 503, and then the signal of the measurement target frequency It checks whether the A2(CA) event is satisfied by comparing the reception strength and the threshold, and by checking the measurement target frequency from the measurement configuration set of the A2(S) event, a disconnection situation with the cell corresponding to the corresponding frequency occurs. Check whether it is. Here, the measurement target frequency of the A2(CA) event may represent the carrier frequency of the P cell of the terminal, and the threshold may be a value greater than the threshold of the A2 event.

If, when the A2 (CA) event is satisfied, the terminal proceeds to step 505 and reports that the A2 (CA) event occurs to the base station. For example, the terminal may report that an A2 (CA) event has occurred to the base station through a measurement report message. Thereafter, in step 507, the terminal may receive a measurement condition for each of the A1 (CA) event, A3 (CA) event, and A2 event, that is, a set of measurement configurations. For example, the terminal may receive an RRC connection reconfiguration message including a measurement configuration set for each of the A1 (CA) event, A3 (CA) event, and A2 event from the base station. In this case, the RRC connection reconfiguration message may include information for requesting to release the setting of the A2 (CA) event measurement configuration set received through the previous RRC connection reconfiguration message.

Thereafter, the terminal checks whether any one of the A1 (CA) event, A3 (CA) event, A2 (S) event, and A2 event is satisfied based on the measurement configuration set in steps 509, 510 and 518. do. That is, the terminal checks the measurement target frequency, threshold value and/or offset from the measurement configuration set of each event, and then compares the signal reception strength and threshold value of the measurement target frequency or receives the signal reception strength of the measurement target frequency and the adjacent signal. It may be determined whether or not the intensity differs by an offset, and it is possible to check whether any one of the A1 (CA) event, A3 (CA) event, A2 (S) event, and A2 event is satisfied. For example, after the UE confirms that the measurement target frequency is the carrier frequency of the P cell from the measurement configuration set of the A1 (CA) event, and the threshold value TH_A1 (CA) is checked, the received signal strength from the P cell is higher than TH_A1 (CA). In large cases, it may be determined that the A1 (CA) event is satisfied. As another example, after the UE confirms that the measurement target frequency is the carrier frequency of the S cell from the measurement configuration set of the A3 (CA) event and the offset OFFSET_A3 (CA), the received signal strength of the adjacent cell is the signal reception strength from the S cell. If it is greater than OFFSET_A3 (CA), it may be determined that the A3 (CA) event is satisfied. As another example, if the measurement target frequency from the measurement configuration set of the A2 event is the carrier frequency of the P cell and the threshold value TH_A2 is checked, and the received signal strength from the P cell is less than TH_A2, the A2 event is satisfied. You can decide. In the drawing, the step of the terminal checking whether an event is satisfied among A1 (CA) event, A3 (CA) event, A2 (S) event, and A2 event is described in steps 509, 510 and 518 for convenience of the city. Although shown separately, it is natural that steps 509, 510, and 518 may consist of one step.

If the A3 (CA) event is satisfied, the terminal proceeds to step 511 and reports the occurrence of the A3 (CA) event to the base station. For example, the terminal may transmit to the base station a measurement report message including information indicating that an A3 (CA) event has occurred and identification information of a neighboring cell whose signal reception strength is greater than the offset value or higher than the signal reception strength of the P cell. . In addition, after reporting the occurrence of the A3 (CA) event, the terminal may receive an RRC connection reconfiguration message requesting release of the configuration of the events of A3 (CA), A1 (CA), A2 (S), and A2.

Thereafter, in step 513, the terminal receives a handover command from the base station that uses the neighboring cell as a P cell, and performs handover in step 515. Thereafter, the UE may receive a handover command message instructing to perform handover using the corresponding neighboring cell as a target Pcell. After handing over to the target cell, the terminal ends the procedure according to an embodiment of the present invention.

On the other hand, when the A1 (CA) event is satisfied, the terminal proceeds to step 517 to report the occurrence of the A1 (CA) event to the base station, and returns to step 501 to perform the following steps again. Here, after reporting the occurrence of the A1 (CA) event, the terminal may receive an RRC connection reconfiguration message requesting a configuration release of the events of A3 (CA), A1 (CA), and A2.

Meanwhile, when the A2 event is satisfied, the terminal proceeds to step 519 to report the occurrence of the A2 event, and proceeds to step 525 to perform the following steps. Here, after reporting the occurrence of the A2 event, the terminal may receive an RRC connection reconfiguration message requesting a configuration release of the events of A3 (CA), A1 (CA), A2 (s), and A2.

On the other hand, when the A2(S) event is satisfied, the terminal proceeds to step 520 to report the occurrence of the A2(S) event to the base station, and proceeds to step 521 to perform the following steps. Here, after reporting the occurrence of the A2(S) event, the UE may receive an RRC connection reconfiguration message requesting release of the event of A3(CA), A1(CA), and A2(S).

Meanwhile, when the A2(S) event is satisfied as a result of the inspection in step 503, the terminal proceeds to step 520 and reports to the base station that an A2(S) event occurs. For example, when the terminal is disconnected from the S cell, the terminal may report the occurrence of an A2(S) event to the base station through a measurement report message. Thereafter, the terminal may receive an RRC connection reconfiguration message including a set of measurement conditions for each of the A2 event and the A4(S) event from the base station, and proceed to step 521.

On the other hand, when the conditions for the A2 event and A4(S) are received from the base station as a result of the test in step 501, the terminal checks the measurement target frequency and the threshold value from the measurement configuration set of the A2 event in step 521, It checks whether the A2 event is satisfied by comparing the signal reception strength and the threshold, and checks the measurement target frequency from the measurement configuration set of the A4(S) event to determine whether a connection status with the cell corresponding to the frequency occurs. Check. Here, the measurement target frequency of the A2 event may represent the carrier frequency of the P cell of the terminal, and the threshold may be a value smaller than the threshold of the A2 (CA) event.

If the A2 event is satisfied, the terminal proceeds to step 523 and reports the occurrence of the A2 event to the base station. For example, the terminal may report that the A2 event has occurred to the base station through the measurement report message.

Thereafter, the terminal may receive a set of measurement configurations for each of the A1 event and A3 event in step 525. For example, the terminal may receive an RRC connection reconfiguration message including a measurement configuration set for each of the A1 event and the A3 event from the base station. In this case, the RRC connection reconfiguration message may include information for requesting to release the setting of the A2 event and the measurement configuration set of the A4(S) event received through the previous RRC connection reconfiguration message.

Thereafter, in step 527, the terminal checks whether any one of the A1 event and the A3 event is satisfied based on the measurement configuration set. That is, the terminal checks the measurement target frequency, threshold value and/or offset from the measurement configuration set of each event, and then compares the signal reception strength and threshold value of the measurement target frequency or receives the signal reception strength of the measurement target frequency and the adjacent signal. It may be determined whether the intensity differs by an offset, and it may be checked whether any one of the A1 event and the A3 event is satisfied. For example, after checking the threshold value TH_A1, the measurement target frequency from the measurement configuration set of the A1 event is the carrier frequency of the P cell (or the cell to which the terminal is connected), and the received signal strength from the P cell is greater than TH_A1. If so, it may be determined that the A1 event is satisfied. Here, TH_A1 may be a value smaller than TH_A1(CA). As another example, the UE has the measurement target frequency from the measurement configuration set of the A3 event is the carrier frequency of the P cell (or the cell to which the UE is connected), and after checking the offset OFFSET_A3, the received signal strength of the adjacent cell is the signal from the P cell. If OFFSET_A3 or more is greater than the reception strength, it may be determined that the A3 event is satisfied.

If the A3 event is satisfied, the terminal proceeds to step 529 and reports the occurrence of the A3 event to the base station. Here, after reporting the occurrence of the A3 event, the UE may receive an RRC connection reconfiguration message requesting a configuration release of the events of A3 and A1. Thereafter, in step 531, the terminal receives a handover command from the base station using the neighboring cell as a P cell, and performs handover in step 533. For example, the UE sends a measurement report message including information indicating that an A3 event has occurred and identification information of a neighboring cell whose signal reception strength is greater than the signal reception strength of the P cell (or the cell to which the UE is connected). Can be transmitted to the base station. Thereafter, the UE may receive a handover command message instructing to perform handover using the corresponding neighboring cell as a target Pcell. After handing over to the target cell, the terminal ends the procedure according to an embodiment of the present invention.

On the other hand, when the A1 event is satisfied, the terminal proceeds to step 535 to report the occurrence of the A1 event to the base station, and returns to step 501 to perform the following steps again. Here, after reporting the occurrence of the A1 event, the UE may receive an RRC connection reconfiguration message requesting a configuration release of the events of A3 and A1.

Meanwhile, when the A4(S) event is satisfied as a result of the inspection in step 521, the terminal reports the occurrence of the A4(S) event in step 537. Here, after reporting the occurrence of the A3 event, the UE may receive an RRC connection reconfiguration message requesting the release of the A4(S) and A2 events. For example, the terminal is a terminal capable of CA support, but only the signal of the Pcell is received at the location of the terminal and the signal of the Scell is not received, so the signal of the Scell is due to the movement of the terminal. When reception is enabled, the terminal can use the P cell and the S cell at the same time. In this way, when the UE additionally uses the S cell while using the P cell, it reports that an A4(S) event has occurred to the base station, and returns to step 501.

6A and 6B are diagrams illustrating a handover control procedure of a terminal in a base station according to another embodiment of the present invention.

6A and 6B, in step 601, the base station checks whether the terminal uses the Pcell and the Scell at the same time. For example, the base station may receive information on a cell currently in use from the terminal, and determine whether the corresponding terminal is a CA terminal using both a Pcell and an Scell, or a non-CA terminal using only the Pcell.

When the terminal uses the P cell and the S cell at the same time, the base station sets an A2 event, an A2 (S) event, and an A5 (CA) event in step 603. For example, the base station may transmit an RRC connection reconfiguration message including a measurement configuration set for each of the A5 (CA) event and the A2 event to the terminal. At this time, the measurement configuration set of the A5 (CA) event is the measurement target of the carrier frequency of the S cell, the measurement configuration set of the A2 event is the measurement target of the carrier frequency of the P cell, and the measurement configuration of the A2 (S) event The three can be measured by the carrier frequency of the S cell.

Thereafter, the base station proceeds to step 605 and checks whether any of the A5 (CA) event, A2 (S) event, and A2 event occurs. The base station may check whether any event occurs among the A5 (CA) event, A2 (S) event, and A2 event through the measurement report message received from the terminal.

If it is confirmed that the A2(S) event has occurred, the base station may cancel the A2(S) event and the A5(CA) event setting in step 606 and set the A4(S) event in step 607. In this case, the base station may maintain the A2 event setting or cancel the A2 event setting and then reset it.

On the other hand, when it is confirmed that the A5 (CA) event has occurred, the base station releases the settings of the A2 (S) event, A5 (CA) event, and A2 event in system 608, and deletes the adjacent cell reported from the terminal in step 609. The handover to the target P cell is determined. For example, when the occurrence of an A5 (CA) event is reported from the terminal, the base station has the signal reception strength of the S cell less than the first threshold when the terminal is located below the heavy electric field of the P cell, and Since the signal reception strength from the neighboring cell of is received greater than the second threshold, it is predicted that the data transmission/reception efficiency of the terminal can be improved to a certain level or higher when handing over to the neighboring cell, and handover the terminal to the neighboring cell. Decide on Sikkim. In this case, the UE performs handover using an adjacent cell as a P cell under the control of the base station, and when an S cell corresponding to the cell exists and is available, the P cell and the S cell may be used together.

On the other hand, when it is confirmed that the A2 event has occurred, the base station sets the A5 event and the A1 event while releasing the A2(S) event, A2 event, and A5(CA) event setting in step 611, and proceeds to step 619 below. do.

Meanwhile, if the terminal uses only the P cell as a result of the inspection in step 601, the base station sets the A2 event and the A4(S) event in step 613, and proceeds to step 615 to determine which one of the A2 event and the A4(S) event in the terminal. Check whether an event of For example, as shown in Table 1, the base station transmits an RRC connection reconfiguration message including a measurement configuration set for an A2 event and a measurement configuration set for an A4(S) event to detect an additional situation of an S cell to the terminal. Thus, the terminal sets up a set of measurement configurations indicating conditions for detecting the occurrence of the A2 event and the A4(S) event, and the measurement reporting that any one of the A2 event and A4(S) event occurs from the terminal. It checks whether a report message is received.

If the A2 event occurs in the terminal, the base station sets the A5 event and the A1 event in step 617, and releases the A2 event and the A4(S) event. For example, the base station includes a measurement configuration set for each of the A5 event and A1 event, and sends an RRC connection reconfiguration message to the terminal requesting release of the measurement configuration set of the A2 event and the measurement configuration set of the A4(S) event. Can be transmitted. At this time, the measurement configuration set of events A1 and A5 is the carrier frequency of the P cell (or the cell being connected) as a measurement target.

Thereafter, the base station proceeds to step 619 and checks whether an event occurs among the A5 event and the A1 event. The base station can check whether an event occurs among the A5 event and the A1 event through the measurement report message received from the terminal. If it is determined that the A5 event has occurred, the base station releases the configuration of the A5 event and the A1 event in step 621, and determines a handover using the adjacent cell reported from the terminal as the target P cell in step 623. On the other hand, when it is determined that the A1 event has occurred, the base station releases the settings of the A5 event and the A1 event in step 625 and returns to step 601.

Meanwhile, when an A4(S) event occurs in the terminal as a result of the inspection in step 615, the base station releases the setting of the A2 event and the A4(S) event in step 629, and proceeds to step 603 to perform the following steps. For example, the terminal is a terminal capable of CA support, but only the signal of the Pcell is received at the location of the terminal and the signal of the Scell is not received, so the signal of the Scell is due to the movement of the terminal. When reception is enabled, the base station allows the terminal to use the P cell and the S cell at the same time. Thereafter, the base station determines that the corresponding terminal uses the P cell and the S cell together, and proceeds to step 603 to perform the following steps.

7 illustrates an operation procedure for handover in a terminal according to an embodiment of the present invention.

Referring to FIG. 7, the UE checks whether a specific handover-related event condition, that is, a measurement configuration set for a measurement report-related event, is received from the base station in step 701. For example, the terminal checks whether a measurement configuration set for a specific measurement report-related event is included in the RRC connection reconfiguration message received from the base station.

When the conditions for the A2 event, A2(S) event, and A5(CA) event are received from the base station, the terminal satisfies any one of the A2 event, A2(S) event, and A5(CA) event in step 703. Check whether it is. For example, the terminal checks the measurement target frequency and threshold values from the measurement configuration set of the A5 (CA) event, and then the signal reception strength of the measurement target frequency is less than the threshold TH1_A5 (CA), and the signal reception strength of the adjacent cell is It is checked whether the A5 (CA) event is satisfied by checking whether it is greater than the threshold TH2_A5 (CA). Here, the measurement target frequency of the A5 (CA) event may represent the carrier frequency of the S cell of the terminal, and each of the threshold values TH1_A5 (CA) and TH2_A5 (CA) of the A5 (CA) event is the threshold values TH1_A5 and TH2_A5 of the A5 event. It can be a value greater than each. As another example, the terminal checks whether the measurement target frequency and the threshold value from the measurement configuration set of the A2 event, and then checks whether the signal reception strength of the measurement target frequency is less than the threshold value TH_A2 to determine whether the A2 event is satisfied. Check. In addition, the terminal checks the measurement target frequency from the measurement configuration set of the A2(S) event and then checks whether the connection with the cell corresponding to the frequency is released.

If the A2 event is satisfied, the terminal proceeds to step 713 and performs the following steps.

Meanwhile, when the A2(S) event is satisfied, the terminal reports the occurrence of the A2(S) event to the base station in step 704. For example, when the connection with the S cell is released, the terminal may report the occurrence of the A2(S) event to the base station through a measurement report message. Thereafter, the UE receives an RRC connection reconfiguration message including a set of measurement conditions for each of the A5 (CA) event and A2 (S) event and the A2 event and A4 (S) event from the base station, and proceeds to step 711. have.

On the other hand, when the A5 (CA) event is satisfied, the terminal proceeds to step 705 and reports the occurrence of the A5 (CA) event to the base station. For example, the terminal may transmit a measurement report message including information indicating that an A5 (CA) event has occurred and identification information of a neighboring cell having a signal reception strength greater than a threshold TH2_A5 (CA) to the base station. In addition, after reporting the occurrence of the A5 (CA) event, the terminal may receive an RRC connection reconfiguration message requesting configuration release of the events of A5 (CA), A2 (S) and A2.

Thereafter, in step 707, the terminal receives a handover command from the base station to use the neighboring cell as a P cell, and performs handover in step 709. Thereafter, the UE may receive a handover command message instructing to perform handover using the corresponding neighboring cell as a target Pcell. After handing over to the target cell, the terminal ends the procedure according to an embodiment of the present invention.

Meanwhile, when the conditions for the A2 event and the A4(S) event are received from the base station as a result of the test in step 701, the terminal checks the measurement target frequency and threshold values from the measurement configuration set of the A2 event in step 711, and then It checks whether the signal reception strength of is less than the threshold TH_A2 to check whether it satisfies the A2 event, checks the measurement target frequency from the measurement configuration set of the A4(S) event, and connects with the cell corresponding to the frequency Check whether a situation occurs. Here, the measurement target frequency of the A2 event may represent the carrier frequency of the P cell (or the cell to which the terminal is connected) of the terminal, and the threshold value TH_A2 of A2 is a value smaller than the threshold value TH_A2 (CA) of the A2 (CA) event. I can.

When the A2 event is satisfied, the terminal proceeds to step 713 and reports that the A2 event occurs to the base station. For example, the terminal may report that the A2 event has occurred to the base station through the measurement report message.

Thereafter, the terminal may receive a set of measurement configurations for each of the A1 event and the A5 event in step 715. For example, the terminal may receive an RRC connection reconfiguration message including a measurement configuration set for each of the A1 event and the A5 event from the base station. In this case, the RRC connection reconfiguration message may include information for requesting to release the setting of the A2 event and the measurement configuration set of the A4(S) event received through the previous RRC connection reconfiguration message.

Thereafter, in step 717, the terminal checks whether any one of the A1 event and the A5 event is satisfied based on the measurement configuration set. That is, the terminal checks the measurement target frequency and the threshold value from the measurement configuration set of each event, and then compares the signal reception strength and the threshold value of the measurement target frequency to determine whether any one of the A1 event and the A5 event is satisfied. Can be checked. For example, after checking the threshold value TH_A1, the measurement target frequency from the measurement configuration set of the A1 event is the carrier frequency of the P cell (or the cell to which the terminal is connected), and the received signal strength from the P cell is greater than TH_A1. If so, it may be determined that the A1 event is satisfied. Here, TH_A1 may be a value smaller than TH_A1(CA). As another example, after the UE checks the threshold values TH1_A5 and TH2_A5 where the measurement target frequency is the carrier frequency of the P cell (or the cell to which the UE is connected) from the measurement configuration set of the A5 event, the received signal strength from the P cell is TH1_A5. If it is smaller than that and the received signal strength from the adjacent cell is greater than TH2_A5, it may be determined that the A5 event is satisfied.

If the A5 event is satisfied, the terminal proceeds to step 719 and reports the occurrence of the A5 event to the base station. Here, after reporting the occurrence of the A5 event, the UE may receive an RRC connection reconfiguration message requesting the release of the A5 event and the A1 event. Thereafter, in step 721, the terminal receives a handover command from the base station to use the neighboring cell as a P cell, and performs handover in step 723. For example, the terminal may transmit a measurement report message including information indicating that an A5 event has occurred and identification information of a neighboring cell having a signal reception strength greater than TH2_A5 to the base station. Thereafter, the UE may receive a handover command message instructing to perform handover using the corresponding neighboring cell as a target Pcell. After handing over to the target cell, the terminal ends the procedure according to an embodiment of the present invention.

On the other hand, when the A1 event is satisfied, the terminal proceeds to step 725 to report the occurrence of the A1 event to the base station, and returns to step 701 to perform the following steps again. Here, after reporting the occurrence of the A1 event, the UE may receive an RRC connection reconfiguration message requesting a configuration release of the events of A5 and A1.

Meanwhile, when the A4(S) event is satisfied as a result of the inspection in step 711, the terminal reports the occurrence of an A4(S) event in the terminal in step 727. Here, after reporting the occurrence of the A4(S) event, the UE may receive an RRC connection reconfiguration message requesting the release of the A4(S) event and the A2 event. For example, the terminal is a terminal capable of CA support, but only the signal of the Pcell is received at the location of the terminal and the signal of the Scell is not received, so the signal of the Scell is due to the movement of the terminal. When reception is enabled, the terminal can use the P cell and the S cell at the same time. In this way, when the UE additionally uses the S cell while using the P cell, it reports that an A4(S) event has occurred to the base station, and returns to step 701.

Embodiments of the invention described in this specification and all functional operations may be implemented by computer software, firmware, or hardware including the structures disclosed herein and equivalent structures thereof, or by a combination of one or more of them. . In addition, embodiments of the invention described herein include one or more computer program products, i.e., one or more modules of computer program instructions executed by a data processing device or encoded on a computer readable medium for controlling the operation of the device. Can be implemented.

The computer-readable medium can be a machine-readable storage medium, a machine-readable storage substrate, a memory device, a composition of materials that affects the machine-readable propagation stream, or a combination of one or more thereof. The term data processing device includes all nodes, devices and machines for processing data including, for example, programmable processors, computers, or multiple processors or computers. In addition to hardware, the node may include code that creates an execution environment for a corresponding computer program, such as a processor firmware, a protocol stack, a database management system, an operating system, or a code constituting one or more combinations thereof.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention is limited to the described embodiments and should not be defined, and should be determined by the scope of the claims and equivalents as well as the scope of the claims to be described later.

Claims (36)

In the method of a base station supporting CA (Carrier Aggregation) in a wireless communication system,
A process of transmitting a first measurement configuration for a first handover event to a terminal, and the first measurement configuration includes a first threshold value,
Receiving a report of the first handover event indicating that the signal strength of the primary cell is lower than the first threshold value from the terminal; and
In response to the report of the first handover event, transmitting a second measurement configuration for the first handover event and a third measurement configuration for the second handover event to the terminal, and the second measurement configuration Contains a second threshold,
Receiving a report of the second handover event from the terminal based on the third measurement configuration for the second handover event; and
In response to the report of the second handover event, transmitting a handover command for handover from the primary cell to a neighboring cell to the terminal, wherein the signal strength of the primary cell is the second threshold value Higher,
The UE receives data from the primary cell and the secondary cell based on the CA.
The method according to claim 1,
The process of determining at least one of a first measurement configuration set including the second measurement configuration, the first measurement configuration, and a second measurement configuration set including the third measurement configuration for the second handover event is further performed. Including,
The first measurement configuration set and the second measurement configuration set are related to handover events including at least one of event A1, event A2, event A3, and event A5,
The event A1 is a handover event that occurs when the signal strength of the serving cell of the terminal is greater than a threshold included in the measurement configuration for the event A1,
The event A2 is a handover event that occurs when the signal strength of the serving cell of the terminal is less than a threshold included in the measurement configuration for the event A2,
The event A3 is a handover event that occurs when the signal strength of the adjacent cell is greater than the signal strength of the serving cell of the terminal by more than a threshold value included in the measurement configuration for event A3,
In the event A5, the signal strength of the serving cell of the terminal is less than a threshold value included in the measurement configuration for the event A5, and the signal strength of the neighboring cell is greater than another threshold value included in the measurement configuration for the event A5. It is a handover event that occurs when
Each measurement configuration includes at least one of measurement frequency information, corresponding handover-related event identification information, at least one threshold value, and offset.
The method according to claim 2,
The first handover event is the event A2,
The second handover event is the event A3,
If the signal strength of the neighboring cell is higher than the signal strength of the primary cell by an offset included in the third measurement configuration for the second handover, the method of receiving the report of the event A3.
The method according to claim 2,
The first handover event is the event A2,
The second handover event is the event A5,
If the signal strength of the neighboring cell is greater than the offset included in the third measurement configuration for the second handover and the signal strength of the primary cell is different from that included in the measurement configuration for the second handover event. If less than a threshold value, the method of receiving the report of the event A5.
The method according to claim 1,
A method comprising transmitting a measurement configuration for detecting a disconnection event from the secondary cell.
In the method of a terminal supporting CA (Carrier Aggregation) in a wireless communication system,
A process of receiving data from a primary cell and a secondary cell based on the CA, and
A process of receiving a first measurement configuration for a first handover event from a base station, and the first measurement configuration includes a first threshold value,
Transmitting a report of the first handover event indicating that the signal strength of the primary cell is lower than a first threshold value to the base station;
In response to the report of the first handover event, the process of receiving a second measurement configuration for the first handover and a third measurement configuration for the second handover event from the base station, and the second measurement configuration Includes a second threshold value,
Transmitting a report of the second handover event to the base station based on a third measurement configuration for the second handover event, and
In response to the report of the second handover event, receiving a handover command for handover from the primary cell to a neighboring cell from the base station, and the signal strength of the primary cell is the second threshold Way higher than the value.
The method of claim 6,
The second measurement configuration is included in a first measurement configuration set, the first measurement configuration and the third measurement configuration for the second handover event are included in a second measurement configuration set,
The first measurement configuration set and the second measurement configuration set are related to handover events including at least one of event A1, event A2, event A3, and event A5,
The event A1 is a handover event that occurs when the signal strength of the serving cell of the terminal is greater than a threshold included in the measurement configuration for the event A1,
The event A2 is a handover event that occurs when the signal strength of the serving cell of the terminal is less than a threshold included in the measurement configuration for the event A2,
The event A3 is a handover event that occurs when the signal strength of the adjacent cell is greater than the signal strength of the serving cell of the terminal by more than a threshold value included in the measurement configuration for event A3,
In the event A5, the signal strength of the serving cell of the terminal is less than a threshold value included in the measurement configuration for the event A5, and the signal strength of the neighboring cell is greater than another threshold value included in the measurement configuration for the event A5. Is a handover event that occurs when
Each measurement configuration includes at least one of measurement frequency information, corresponding handover-related event identification information, at least one threshold value, and offset.
The method of claim 7,
The first handover event is the event A2,
The second handover event is the event A3,
If the signal strength of the neighboring cell is higher than the signal strength of the primary cell by an offset included in the third measurement configuration for the second handover, the report of the event A3 is transmitted by the terminal. Way.
The method of claim 7,
The first handover event is the event A2,
The second handover event is the event A5,
If the signal strength of the neighboring cell is greater than the offset included in the third measurement configuration for the second handover and the signal strength of the primary cell is different from that included in the measurement configuration for the second handover event. If less than a threshold value, the report of the event A5 is transmitted.
The method of claim 6,
And receiving a measurement configuration for detecting a disconnection event from the secondary cell.
In a base station supporting CA (Carrier Aggregation) in a wireless communication system,
Including at least one transceiver,
The at least one transceiver,
Transmits a first measurement configuration for a first handover event to the terminal, and the first measurement configuration includes a first threshold value,
Receiving a report of the first handover event indicating that the signal strength of the primary cell is lower than the first threshold value from the terminal; and
In response to the report of the first handover event, a second measurement configuration for the first handover event and a third measurement configuration for a second handover event are transmitted to the terminal, and the second measurement configuration is a second measurement configuration. Contains the threshold,
Receiving a report of the second handover event from the terminal based on the third measurement configuration for the second handover event,
In response to the report of the second handover event, configured to transmit a handover command for handover from the primary cell to a neighboring cell to the terminal,
The terminal is a base station for receiving data from the primary cell and the secondary cell based on the CA.
The method of claim 11,
Further comprising at least one processor,
The at least one processor,
Configured to determine at least one of a first measurement configuration set including the second measurement configuration, the first measurement configuration, and a second measurement configuration set including the third measurement configuration for the second handover event,
The first measurement configuration set and the second measurement configuration set are related to handover events including at least one of event A1, event A2, event A3, and event A5,
The event A1 is a handover event that occurs when the signal strength of the serving cell of the terminal is greater than a threshold included in the measurement configuration for the event A1,
The event A2 is a handover event that occurs when the signal strength of the serving cell of the terminal is less than a threshold included in the measurement configuration for the event A2,
The event A3 is a handover event that occurs when the signal strength of the adjacent cell is greater than the signal strength of the serving cell of the terminal by more than a threshold value included in the measurement configuration for event A3,
In the event A5, the signal strength of the serving cell of the terminal is less than a threshold value included in the measurement configuration for the event A5, and the signal strength of the neighboring cell is greater than another threshold value included in the measurement configuration for the event A5. Is a handover event that occurs when
Each measurement configuration set includes at least one of measurement frequency information, corresponding handover-related event identification information, at least one threshold value, and offset.
The method of claim 12,
The first handover event is the event A2,
The second handover event is the event A3,
If the signal strength of the neighboring cell is higher than the signal strength of the primary cell by an offset included in the third measurement configuration for the second handover, the base station receiving the report of the event A3.
The method of claim 13,
The first handover event is the event A2,
The second handover event is the event A5,
If the signal strength of the neighboring cell is greater than the offset included in the third measurement configuration for the second handover and the signal strength of the primary cell is different from that included in the measurement configuration for the second handover event. If less than the threshold value, the base station receiving the report of the event A5.
The method of claim 11,
The at least one transceiver,
A base station configured to transmit a measurement configuration to detect a disconnection event from the secondary cell.
In a terminal supporting CA (Carrier Aggregation) in a wireless communication system,
Including at least one transceiver,
The at least one transceiver,
Receive data from a primary cell and a secondary cell based on the CA,
Receiving a first measurement configuration for a first handover event from the base station, the first measurement configuration including a first threshold value,
Transmitting a report of the first handover event indicating that the signal strength of the primary cell is lower than a first threshold value to the base station,
In response to the report of the first handover event, a second measurement configuration for the first handover and a third measurement configuration for a second handover event are received from the base station, and the second measurement configuration is a second measurement configuration. Contains the threshold,
Transmitting a report of the second handover event to the base station based on a third measurement configuration for the second handover event,
In response to the report of the second handover event, configured to receive a handover command for handover from the primary cell to a neighboring cell from the base station, and the signal strength of the primary cell is greater than the second threshold value. High terminal.
The method of claim 16,
The second measurement configuration is included in a first measurement configuration set, the first measurement configuration and the third measurement configuration for the second handover event are included in a second measurement configuration set,
The first measurement configuration set and the second measurement configuration set are related to handover events including at least one of event A1, event A2, event A3, and event A5,
The event A1 is a handover event that occurs when the signal strength of the serving cell of the terminal is greater than a threshold included in the measurement configuration for the event A1,
The event A2 is a handover event that occurs when the signal strength of the serving cell of the terminal is less than a threshold included in the measurement configuration for the event A2,
The event A3 is a handover event that occurs when the signal strength of the adjacent cell is greater than the signal strength of the serving cell of the terminal by more than a threshold value included in the measurement configuration for event A3,
In the event A5, the signal strength of the serving cell of the terminal is less than a threshold value included in the measurement configuration for the event A5, and the signal strength of the neighboring cell is greater than another threshold value included in the measurement configuration for the event A5. Is a handover event that occurs when
Each measurement configuration set includes at least one of measurement frequency information, corresponding handover-related event identification information, at least one threshold value, and offset.
The method of claim 17,
The first handover event is the event A2,
The second handover event is the event A3,
If the signal strength of the neighboring cell is higher than the signal strength of the primary cell by an offset included in the third measurement configuration for the second handover, the terminal to which the report of the event A3 is transmitted.
The method of claim 17,
The first handover event is the event A2,
The second handover event is the event A5,
If the signal strength of the neighboring cell is greater than the offset included in the third measurement configuration for the second handover and the signal strength of the primary cell is different from that included in the measurement configuration for the second handover event. If less than the threshold value, the terminal to which the report of the event A5 is transmitted.
The method of claim 16,
The transmission/reception unit receives a measurement configuration for detecting a connection release event from the secondary cell.
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