KR101831689B1 - Apparatus and method for providing handover support inforamtion in mobile communication system - Google Patents

Abstract

A method for providing information necessary for performing a measurement report trigger after a base station measures a neighboring base station in a mobile communication system in a mobile communication system, the method comprising the steps of: And providing a Time-to-Trigger to an MS in an idle mode, and a step of providing independent Treselection to a MS in an idle mode when the MS is in an idle mode. There is an advantage that the over execution success rate can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an apparatus and a method for providing handover support information in a mobile communication system,

The present invention relates to an apparatus and a method for providing time-to-trigger (TTT) for handover of a terminal and treselection for reselection of a terminal in a mobile communication system.

Recently, the demand for high-speed data service in the mobile communication system has continuously increased. Considering coverage, interest in microcells (or Picocells, Hotzone, Femtocells, etc.) is rising because data services are mainly generated in certain small areas.

The characteristics of the micro cell are as follows. The microcells may have a smaller coverage than the macrocells and may overlap the macrocells. The microcell can operate at the same or different frequency as the macrocell, and uses less transmission power than the macro base station.

However, when handover from a macrocell to a microcell is performed by a terminal, a handover failure probability is high when a set value for handover that was used between macrocells is used.

It is an object of the present invention to provide an apparatus and method for providing handover support information in a mobile communication system.

It is another object of the present invention to provide an apparatus and method for providing a TTT for handover of a terminal in a mobile communication system.

It is still another object of the present invention to provide an apparatus and a method for providing Treselection for cell reselection of a terminal.

Another object of the present invention is to provide an apparatus and method for negotiating TTT-related information between base stations in a 3GPP LTE system in order to support a stable handover success in macro / microcell handover.

It is another object of the present invention to provide an apparatus and method for a serving base station to transmit an independent TTT value to an active mode terminal for a specific neighboring base station in order to perform stable handover between macros / micro cells in a 3GPP LTE system.

It is still another object of the present invention to provide an apparatus and a method capable of transmitting independent Treselection values to specific idle mode access points (MSs) of a BS in order to perform stable cell reselection between macros / micro cells in a 3GPP LTE system .

According to a first aspect of the present invention, there is provided a method for providing information necessary for performing a measurement report trigger after a base station measures a neighboring base station in a mobile communication system, In the case of the UE, a process of providing a time-to-trigger (TTT) independent of a specific neighboring base station to the active mode UE and a process of providing independent Treselection to the UE of the idle mode, The method comprising the steps of:

According to a second aspect of the present invention, in a method for transmitting handover information of a mobile station to a base station in a mobile communication system, a mobility change message including mobility change information is transmitted to a neighboring base station, And receiving a response message to the mobility change message.

According to a third aspect of the present invention, there is provided a method for acquiring mobility information of a neighbor BS in a mobile communication system, the method comprising: receiving mobility information of a BS through a control message when the MS is in an active mode; And receiving the mobility information of the base station through the system information block when the terminal is in the idle mode.

According to a fourth aspect of the present invention, there is provided a base station apparatus for providing information of a neighboring base station to a mobile station in a mobile communication system, the mobile station generating an independent TTT for a specific neighboring base station, Mode terminal, a controller for generating independent Treselection for each specific neighboring base station, and a transmitter for transmitting the generated TTT to the terminal in the active mode and transmitting the generated Treselection to the terminal in the idle mode.

According to a fifth aspect of the present invention, there is provided a base station apparatus for transmitting handover information of a mobile station to another base station in a mobile communication system, the mobile station including a controller for generating a mobility change message including mobility change information, And a receiver for receiving a response message to the mobility change message.

According to a sixth aspect of the present invention, there is provided an apparatus for acquiring mobility information of a neighbor base station in a mobile communication system, the mobile station acquiring mobility information of a base station through a control message when the mobile station is in an active mode, A control unit for obtaining mobility information of a base station through a system information block when the terminal is in an idle mode, and a receiver for receiving the control message and the system information block.

The present invention has an advantage of improving the success rate of macro / micro-cell handover because it negotiates TTT-related information between base stations so that the MS can support a stable handover success when macro / micro-cell handover is performed.

Also, in the present invention, in order to perform a stable handover between macros / micro cells in the LTE system, the serving BS can transmit an independent TTT value to the active mode UE for each neighboring BS.

Also, in the present invention, in order to perform stable cell reselection between macros / micro cells in an LTE system, a base station can transmit an independent Treselection value to neighbor cells of a specific cell type It is advantageous to improve the success rate of macro / microcell handover.

1 is a diagram illustrating an example of a heterogeneous network according to an embodiment of the present invention.
2 is a message flow diagram for transmitting a measurement report message according to an embodiment of the present invention.
3 is a diagram illustrating a change in downlink received signal strength during handover from a macrocell to a microcell according to an embodiment of the present invention.
4 is a diagram illustrating a handover process according to a location of a terminal when a terminal performs handover from a macrocell to a macrocell according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a handover process according to a location of a terminal when a terminal performs a handover from a macrocell to a microcell according to an embodiment of the present invention.
6 is a diagram illustrating a handover process according to a location of a mobile station when a mobile station handover from a macrocell to a microcell according to another embodiment of the present invention.
FIG. 7 is a diagram illustrating a process of Mobilty chgange of a base station according to an embodiment of the present invention.
FIG. 8 is a flowchart illustrating a Mobilty chgange of a base station according to an embodiment of the present invention.
FIG. 9 is a message flow diagram illustrating a method for delivering independent TTT (Time-to-Trigger) and Treselection values to neighboring BSs in a serving BS according to an exemplary embodiment of the present invention.
10 is a flowchart illustrating a method of transmitting independent TTTs and Treselection values to neighboring BSs in a serving BS according to an embodiment of the present invention.
11 is a diagram illustrating a case where independent TTT values are set for specific neigh- boring cells according to an embodiment of the present invention.
FIG. 12 illustrates a case where independent TTT-SF values are set for specific neigh- boring cells according to an embodiment of the present invention, but SF values set in consideration of the existing terminal speed conditions are set.
FIG. 13 shows a case where independent TTT-SF values are set for specific neighouring cells according to an embodiment of the present invention, but new SF values are newly set.
FIG. 14 illustrates a method of setting an independent TTT value for each neighboring cell belonging to a specific cell type in a 'MeasObjectEUTRA' IE according to an embodiment of the present invention.
FIG. 15 illustrates a method of setting an independent TTT value for each neighboring cell belonging to a specific cell type in a 'ReportConfigEUTRA' IE according to an embodiment of the present invention.
FIG. 16 illustrates a case where an independent TTT-SF value for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention is set by applying SF values set in consideration of the existing terminal speed state to the 'MeasObjectEUTRA' IE .
FIG. 17 illustrates a case where a separate TTT-SF value is set for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention, and another TTT-SF value is set in the 'MeasObjectEUTRA' IE.
FIG. 18 shows a case where independent TTT-SF values for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention are set to 'ReportConfigEUTRA' IE by applying SF values set in consideration of the existing terminal speed state.
FIG. 19 illustrates a case where a separate TTT-SF value is set for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention, and another TTT-SF value is set in the 'ReportConfigEUTRA' IE.
FIG. 20 illustrates a case where an independent Treselection value is set for each specific neighboring cell according to an embodiment of the present invention.
FIG. 21 illustrates a case where SF values set in consideration of an existing terminal speed are applied to independent Treselection-SF values for specific neighboring cells according to an embodiment of the present invention.
FIG. 22 shows a case where SFs are newly set to independent Treselection-SF values for specific neighbors according to an embodiment of the present invention.
FIG. 23 illustrates a case where a Treselection value is set for each specific neighboring cell according to an embodiment of the present invention.
FIG. 24 illustrates a case in which Treselection-SF values for specific neighbors according to an embodiment of the present invention are set using SF values set in consideration of existing terminal speeds.
FIG. 25 illustrates a case where SFs are newly set in consideration of existing terminal speeds for each Treselection-SF value for each specific neighboring cell according to an embodiment of the present invention.
26 is a block diagram of a base station and a terminal according to an embodiment of the present invention.
27 is a diagram illustrating an environment for performance analysis according to an embodiment of the present invention.
28 is a graph showing a HO Fail Ratio result in the case of a load factor of 50% and UL IoT of 5 dB according to an embodiment of the present invention.
FIG. 29 is a diagram illustrating a HO Fail Ratio result when the load factor is 100% and the UL IoT is 7 dB according to the embodiment of the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, an apparatus and method for providing handover support information in a mobile communication system will be described.

3GPP RAN WG1 considers Heterogenoues Network as an LTE-Advanced study item from the October 2009 meeting. A Heterogeneous Network (hereinafter referred to as HetNet) refers to a cellular deployment in which base stations using a small transmission power within a base station area are overlaid.

That is, in HetNet, cells of different sizes are mixed or overlaid. Here, all base stations use the same radio transmission technology.

1 is a diagram illustrating an example of a heterogeneous network according to an embodiment of the present invention.

Referring to FIG. 1, pico cells 130 and 140 and femtocells 150, 160, and 170 exist in a region managed by a macro base station 100 of a heterogeneous network, and radio networks 110 and 120, Lt; / RTI >

The present invention will be described taking the 3GPP LTE series system as an embodiment.

The present invention relates to a method for effectively supporting handover when a terminal performs macro / micro-cell handover in a heterogeneous network deployment.

Particularly, in the present invention, a method for negotiating TTT (Time-to-Trigger) related information between base stations in a 3GPP LTE system will be described.

The present invention also relates to a method for efficiently supporting cell reselection triggering when a terminal operating in an idle mode performs macro / micro cell cell reselection.

In the 3GPP LTE system, the serving BS can transmit independent TTT and Treselection values to neighboring BSs.

The active mode UE measures the RSRP of the serving BS and the target BS, and then compares the received signal strengths. Thereafter, if the measurement trigger condition is satisfied, the UE transmits a Measurement Report message to the serving BS.

In the LTE system, there are several kinds of measurement trigger conditions, but the most commonly used measurement trigger condition is Event A3.

After satisfying the Entering condition, if the Leaving condition does not occur during TTT (Time-to-Trigger) time, the terminal generates an event. Here, the TTT value means the time for the measurement event to satisfy the measurement trigger condition to be triggered. In the LTE system, one of 16 values can be selected and applied according to the terminal speed.

The Ocn value is offset or added to or subtracted from the neighboring cell signal level during handover, and can be set differently for each specific cell. The Ocs value is an offset value added to or subtracted from the serving cell signal level at the time of handover, and is a parameter existing for each specific cell.

Upon receiving the Measurement Report from the UE, the serving BS determines whether to hand over the UE based on Radio Resource Management (RRM) information.

2 is a message flow diagram for transmitting a measurement report message according to an embodiment of the present invention.

Referring to FIG. 2, there are various types of measurement report triggering conditions in the LTE system, but the most commonly used measurement report triggering condition is the above-described event A3.

The MME 230 or the serving gateway 240 has area restriction information (step a).

The serving base station 220 transmits a 'Measurement Control' message to the UE 210 to provide various values necessary for performing the measurement report triggering (step b). One of the values provided is the TTT value. The Measurement Control message is an RRC Connection Reconfiguration message including 'measConfig' IE in the LTE system.

Event If the Leaving Condition does not occur during the TTT time after the Entering Condition in A3 is satisfied, an event occurs. Here, the TTT value means a time required for the measurement report event to satisfy the measurement report triggering condition to be triggered. The TTT value will be described in more detail as follows.

First, if the Entering Condition is satisfied for the first time, the terminal 210 activates the TTT-related timer. Then, when the UE 210 continues to satisfy the Entering Condition for the TTT time, the Node 210 transmits a 'Mesurement Report' message to the serving or source base station 22 (step c).

If the Entering Condition is not satisfied within the TTT time, the TTT related timer is reset to the initial TTT value. If a Leaving Condition occurs, the TTT related timer is released.

Upon receiving the 'Measurement Report' message from the terminal 210, the source base station 220 determines whether to hand over the terminal 210 to the target base station 230 by referring to RRM (Radio Resource Management) information (Step d).

Hereinafter, a process of performing cell reselection triggering by the idle mode UE will be described.

When the terminal is operating in idle mode, it performs measurements for cell reselection purposes. In general, the UE determines whether to perform cell reselection. The measurement rules for cell reselection triggering in LTE system are as follows.

If SServingCell is less than Sintrasearch or Sintrasearch is not delivered to the serving cell, the terminal in this mode performs intra-frequency measurements. If Sintrasearch is delivered to the serving cell and SServingCell is greater than Sintrasearch, the terminal no longer needs to perform intra-frequency measurements.

Here, SServingCell represents the reception level value (in dB) of the serving cell and Sintrasearch represents the threshold value (in dB) for intra-frequency measurements. The Treselection value for the idle mode terminal is similar to the TTT value for the active mode terminal.

The Treselection value will be described in more detail as follows. First, if the cell reselection triggering condition is satisfied first, the UE activates a timer related to the Treselection.

Thereafter, if the cell reselection triggering condition is continuously satisfied during the Treselection time, the UE performs a cell reselection process. If the cell reselection triggering condition is not satisfied within the Treselection time, the Treselection related timer is reset to the initial Treselection value.

3 is a diagram illustrating a change in downlink received signal strength during handover from a macrocell to a microcell according to an embodiment of the present invention.

3, when the macrocell 310 and the microcell 320 operate at the same frequency under an environment in which the microcell 320 is superimposed in the macrocell 310, 310 to the micro cell 320, the interference from the base station of the micro cell 320 is rapidly increased near the microcell 320, and the channel environment is rapidly deteriorated.

Also, the terminal 300 also has severe uplink interference to the base station of the microcell 320. This is because the path loss between the base station and the terminal 300 of the microcell 320 changes more rapidly than the path loss between the base station and the terminal 300 of the macrocell 310. Therefore, the MS 300 undergoes a Radio Link Failure (RLF) before performing the handover to the microcell 320.

In particular, when the MS 300 moves from the macrocell 310 to the microcell 320 at a high speed, the relatively long TTT parameter value applied to the handover between the macrocells 310 is maintained The handover to the microcell 320 is delayed, and the probability of occurrence of the RLF rapidly increases.

To solve this problem, it is necessary to apply a separate parameter (handover trigger threshold, Time-To-Tigger) suitable for handover between the macrocell 310 and the microcell 320.

In order to support handover between the stable macrocell 310 and the microcell 320, both of the following must be satisfied.

The handover trigger threshold value and the TTT value are separately applied to the serving base station, and the handover trigger threshold value and the TTT value are transmitted to the serving base station. And transmit it to the terminal).

Accordingly, it means that the HO trigger threshold value and the TTT value can be differently applied to the MS 300 according to whether the target BS is the base station of the macrocell 310 or the BS of the microcell 320.

Second, the serving base station must know which handover trigger threshold value and TTT value should be applied to neighbor target base stations. So that the first requirement can be met. There is no way to negotiate TTT values between base stations with current standards.

FIGS. 4, 5 and 6 illustrate this problem. Here, the handover trigger threshold value refers to an offset value in the event A3.

4 is a diagram illustrating a handover process according to a location of a terminal when a terminal performs handover from a macrocell to a macrocell according to an embodiment of the present invention.

Referring to FIG. 4, when the UE performs handover from macro cell 1 to macro cell 2, if the handover threshold value between macro cell 2 and macro cell 1 is greater than HO_Threshold (step 1), an A3 event occurs, If the A3 event is maintained to be greater than the TTT value (step 2), the UE transmits a Measurement Report message to the macrocell 1 (step 3). The macrocell 1 determines whether or not the UE is handed over and transmits an HO_Command message To the MS (step 4).

FIG. 5 is a diagram illustrating a handover process according to a location of a terminal when a terminal performs a handover from a macrocell to a microcell according to an embodiment of the present invention.

Referring to FIG. 5, in the handover process (steps 1 to 4), when the parameters applied at the time of handover from the macrocell to the macrocell are directly used, the handover fails due to abrupt interference (step 4).

6 is a diagram illustrating a handover process according to a location of a mobile station when a mobile station handover from a macrocell to a microcell according to another embodiment of the present invention.

Referring to FIG. 6, a parameter optimized for handover from a macrocell to a microcell is applied in a handover process (steps 1 to 4). As shown in FIG. 6, the handover to the microcell of the MS is performed before the abrupt interference is received (steps 1 and 2), and the handover is successful.

As described above, in order to support handover between stable macrocells / microcells, the serving base station should be able to apply the independent handover trigger threshold value and the TTT value to neighboring BSs and transmit these parameter values to the UEs.

That is, a handover trigger threshold value and a TTT value for each PCI of the handover target base station must be applied and transmitted to the UE. Accordingly, if the UE receives the 'Measurement Report' message by applying the HO trigger threshold value and the TTT value differently depending on whether the handover target BS is a macro BS or a micro BS, the MS can push the handover successfully.

The Handover trigger threshold value is expressed as a cellIndividauloffset value in a 'MeasObjectEUTRA' information element (IE). The 'MeasObjectEUTRA' IE includes information necessary for the active mode UE to measure neighbor cells.

However, in the current LTE standard, the serving base station can not transmit the TTT value to the mobile station by the neighboring base station. The Treselection value, like the TTT value, can not be transmitted to the UE in the current LTE standard.

As described above, the present invention provides an apparatus and method for negotiating TTT-related information between base stations through an X2 interface in a 3GPP LTE system.

According to the LTE specification, the "Mobility Settings Procedure" is defined as one of the Elementary Procedures. This procedure is a procedure for negotiating mobility-related parameters to be changed through the X2 interface with the neighboring base station when the base station desires to change mobility-related parameters.

In the current standard, the handover tigger threshold value change negotiation function can be performed for the purpose of load balancing or handover optimization between the base stations through the above procedure.

In the present invention, the TTT-related information negotiation between the base stations via the X2 interface uses the "Mobility Settings Procedure ".

FIG. 7 is a diagram illustrating a process of Mobilty chgange of a base station according to an embodiment of the present invention.

7, the first base station 710 transmits to the second base station 720 connected to the X2 interface the optimized TTT value related information to the base station 710 from the base station 2 720 to the base station 710 Quot; MOBILITY CHANGE REQUEST "message (step a).

That is, the message contains TTT-related information optimized for its own cell. After receiving the message, the second BS 720 determines whether the TTT value related information is an acceptable value.

If the base station 2 720 determines that it is an acceptable value, it transmits a message "MOBILITY CHANGE ACKNOWLEDGE" as a response message to the first base station 710 (step b). If the base station 2 720 does not accept the requested TTT value related information, it transmits a 'MOBILITY CHANGE FAILURE' message to the first base station 710 (step b).

In the "MOBILITY CHANGE REQUEST" message, the TTT related information can be added in the following two ways. In the current LTE standard, there is an IE called "eNB2 Proposed Mobility Parameters ", which is an IE of" Mobility Parameters Information ", which is mobility related parameter information to be used for handover proposed by the first base station 710 to the second base station 720, As shown in the following table.

IE / Group Name Presence Range IE type and Reference Semantics description Handover Tigger Change M INTEGER (-20..20) The actual value is the IE value * 0.5 dB

Here, the Handover Trigger threshold means a threshold value for initializing a handover preparation procedure for a specific neighbor cell, and the Handover Trigger Change means a change value for the threshold.

In the present invention, there are two ways to transmit TTT related information.

(1) A method of negotiating the TTT related information in terms of dB value will be described as follows.

The above scheme is a method for allowing existing Handover Trigger Change to express not only the threshold but also the TTT. To this end, the present invention proposes to add a "Handover Trigger Type" IE to the Mobility Parameters Information IE. Therefore, the Mobility Parameters Information IE reflecting this is shown in the following table.

IE / Group Name Presence Range IE type and Reference Semantics description Handover Tigger Change M INTEGER (-20..20) The actual value is the IE value * 0.5 dB Handover Trigger Type M ENUMERATED {Threshold, TimeToTrigger ..}

For example, if the base station 1 710 sets Handover Trigger change to '-3dB' in the Mobility Information IE corresponding to the Proposed Mobility Parameters of the MOBILITY CHANGE REQUEST message to the Node B 2 720 and sets 'Handover Trigger Type' to 'TimeToTrigger' And transmits it. When the second base station 720 receives the first base station 720, the second base station 720 reduces the TTT value for the first base station 710 by 0.5 times.

The TTT values in the LTE specification are in the range of ms0, ms40, ms64, ms80, ms100, ms128, ms160, ms256, ms320, ms480, ms512, ms640, ms1024, ms1280, ms2560, How you change it depends on the implementation method.

(2) TTT-related information is expressed as an absolute value, and a negotiation method will be described as follows.

The above scheme is a method of adding a new IE to allow negotiation of an absolute value for the TTT, assuming that the handover trigger change is a change value for the threshold. The IE includes TTT1 ms, TTT2 ms, ... , And TTTn ms. The Mobility Parameters Information IE reflecting this is shown in the following table.

FIG. 8 is a flowchart illustrating a Mobilty chgange of a base station according to an embodiment of the present invention.

Referring to FIG. 8, when an event for transmitting a TTT or a threshold (Handover Trigger Threshold) value is generated in step 810, the base station transmits a TTT or a Threshold (Handover Trigger Threshold) value to a neighboring base station (Step 820).

Here, the transmitted event may be a case where the TTT or the threshold (Handover Trigger Threshold) value for the corresponding base station is changed, a new base station is added, and a new base station transmits the event.

The present invention proposes a scheme for transmitting independent TTT (Time-to-Trigger) and Treselection values to neighboring BSs in the LTE system.

FIG. 9 is a message flow diagram illustrating a method for transmitting independent TTT and Treselection values to neighboring BSs by a serving BS according to an exemplary embodiment of the present invention.

9, the base station 910 transmits a TTT, a TTT_SF / Treslection or a Treseleciton-SF to an active mode or an idle mode terminal 920 (step a). This will be described in detail below.

10 is a flowchart illustrating a method of transmitting independent TTT and Treselection values to neighboring BSs by a serving BS according to an embodiment of the present invention.

Referring to FIG. 10, if the serving BS is an active mode terminal (step 1010) and differentiates according to the cell type (step 1015), the serving TTT value or the TTT-SF value for each neighboring cell belonging to a specific cell type (Step 1025).

In step 1015, the serving BS sets an independent TTT value or a TTT-SF value for each specific neighboring cell and transmits the selected TTT value to the serving BS in step 1020.

If the serving base station is an idle mode terminal that is not an active mode terminal (step 1010) and the cell is classified according to a cell type (step 1030), the serving base station sets an independent Treselection value or Treselection-SF value for each neighboring cell belonging to a specific cell type (Step 1040).

In step 1030, the serving BS sets an independent Treselection value or a Treselection-SF value for each specific neighboring cell in step 1030, if the target is an idle mode UE in step 1010 and does not distinguish according to cell type in step 1030.

(1) A method for a base station to transmit an independent TTT value to an active mode terminal for each neighboring base station will be described.

11 is a diagram illustrating a case where independent TTT values are set for specific neigh- boring cells according to an embodiment of the present invention.

Referring to FIG. 11, a method 1-1 for setting an independent TTT value for each specific neighouring cell is performed. In the LTE system, the 'MeasObjectEUTRA' IE includes information necessary for an active mode UE to measure neighboring cells do.

In FIG. 11, a 'cellIndividualTimeToTrigger' field in red is added to the 'MeasObjectEUTRA' IE. The added 'cellIndividualTimeToTrigger' field indicates a cell individual TTT value applied to a specific neighboring cell.

The 'cellIndividualTimeToTrigger' field is similar to the conventional 'cellIndividualOffset' field, and is a Paris marker related to measurement report triggering which is independently applied to neighbor cells. Therefore, the UE can apply independent TTT values to neighboring BSs, and cellIndividualTimeToTrigger is shown in the following table.

cellIndividualTimeToTrigger
Cell individual time to trigger parameter applicable to a specific neighbouring cell.

FIG. 12 illustrates a case where independent TTT-SF values are set for specific neigh- boring cells according to an embodiment of the present invention, but SF values set in consideration of the existing terminal speed conditions are set.

Referring to FIG. 12, a method 1-2 for setting an independent TTT-SF value for each specific neighouring cell is performed. In the current LTE standard, a 'speed-dependent' scaling factor ) Is applied. When the active mode terminal is high and medium mobility, the sf-high value and the sf-Medium value are multiplied by TTT, respectively.

Therefore, when the terminal is fast, a TTT value less than the originally given TTT value can be applied. This is because if the terminal is at a high speed, it is necessary to set a small TTT to increase the probability of successful handover.

In such a scheme, the SF values set in consideration of the terminal speed state described in the current LTE standard can be reused as they are, or the SF values can be newly set separately.

12 is a flowchart (1-2-1) for applying and setting the SF values set in consideration of the existing terminal speed conditions. As shown in FIG. 11, the 'MeasObjectEUTRA' cellIndividualTimeToTrigger-SF 'field.

The added 'cellIndividualTimeToTrigger-SF' field is a cell individual TTT-SF value applied to a specific neighbor cell. In the case of a particular neighbor cell, the SF value may be multiplied by the originally given TTT value to shorten the TTT.

Here, the 'SpeedStateScaleFactors' IE, which is the SF values set in consideration of the terminal speed state, is applied as it is in the current LTE standard. And CellIndividualTimeToTrigger-SF are shown in the following table.

CellIndividualTimeToTrigger-SF
Cell individual scaling factor applicable to a specific neighbouring cell. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

FIG. 13 shows a case where independent TTT-SF values are set for specific neighouring cells according to an embodiment of the present invention, but new SF values are newly set.

Referring to FIG. 13, additional SF values are newly set (1-2-2), and 'cellIndividualTimeToTrigger-SF' field represented in red in 'MeasObjectEUTRA' IE is added.

The added 'cellIndividualTimeToTrigger-SF' field is a cell individual TTT-SF value applied to a specific neighbor cell. In the case of a particular neighbor cell, the SF value may be multiplied by the originally given TTT value to shorten the TTT.

Here, 'Scene Factor Scale Factors' IE, which is an IE related to the Scaling Factor newly defined in the present invention, is used, and CellIndividualTimeToTrigger-SF is as follows.

CellIndividualTimeToTrigger-SF
Cell individual scaling factor applicable to a specific neighbouring cell. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

Here, the values of x_1, x_2, ..., x_n are mapped to values between 0 and 1.

FIG. 14 illustrates a method of setting an independent TTT value for each neighboring cell belonging to a specific cell type in a 'MeasObjectEUTRA' IE according to an embodiment of the present invention.

Referring to FIG. 14, an independent TTT value is set for each neighboring cell belonging to a specific cell type. The independent TTT value for each neighboring cell belonging to a specific cell type is set to 'MeasObjectEUTRA' IE (1-3-1).

First, considering the setting in the 'MeasObjectEUTRA' IE, a new 'cellTypesList' field is presented in red in the 'MeasObjectEUTRA' IE. The field is designed to have different TTT values for different PCI ranages, and the cell type list is shown in the following table.

CellTypesList
List of cell types having different specific time periods for which the event needs to be met in order to trigger a measurement report.

FIG. 15 illustrates a method of setting an independent TTT value for each neighboring cell belonging to a specific cell type in a 'ReportConfigEUTRA' IE according to an embodiment of the present invention.

Referring to FIG. 15, a method (1-3) for setting independent TTT values for neighboring cells belonging to a specific cell type, wherein independent TTT values for each neighboring cell belonging to a specific cell type are set in ReportConfigEUTRA 'IE (1-3-2). 'ReportConfigEUTRA' We propose a new 'cellTypesList' field in red in IE. The field is designed to have different TTT values for different PCI ranages, and the cell type list is shown in the following table.

CellTypesList
List of cell types having different specific time periods for which the event needs to be met in order to trigger a measurement report.

FIG. 16 illustrates a case where an independent TTT-SF value for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention is set by applying SF values set in consideration of the existing terminal speed state to the 'MeasObjectEUTRA' IE .

Referring to FIG. 16, an independent TTT-SF value is set for each neighboring cell belonging to a specific cell type. The independent TTT-SF value for each neighboring cell belonging to a specific cell type is' MeasObjectEUTRA 'IE (1-4-1) or' ReportConfigEUTRA 'IE (1-4-2).

As shown in the figure, a new 'cellTypesList' field is presented in red in the 'MeasObjectEUTRA' IE. The field is designed to have different TTT-SF values for different PCI ranage cell types.

Similarly to the above (1-2) scheme, the SF values set in consideration of the terminal speed state described in the current LTE standard can be reused and applied as it is in the above method (1-4-1) 1), where the cell type list is shown in the table below.

CellTypesList
List of cell types having individual scaling factors applicable to a neighbouring cell (s) belonging to a specific cell type. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

FIG. 17 illustrates a case where a separate TTT-SF value is set for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention, and another TTT-SF value is set in the 'MeasObjectEUTRA' IE.

Referring to FIG. 17, a method for setting an independent TTT-SF value for each neighboring cell belonging to a specific cell type, wherein an independent TTT-SF value for each neighboring cell belonging to a specific cell type is' MeasObjectEUTRA 'IE (1-4-1) or' ReportConfigEUTRA 'IE (1-4-2).

As shown in the figure, a new 'cellTypesList' field is presented in red in the 'MeasObjectEUTRA' IE. The field is designed to have different TTT-SF values for different PCI ranage cell types.

Similar to the above (1-2), the SF values may be separately set in consideration of the terminal speed state described in the current LTE standard in the above method (1-4-1) (1-4-1-2). The cell type list is shown in the following table.

CellTypesList
List of cell types having individual scaling factors applicable to a neighbouring cell (s) belonging to a specific cell type. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

Here, x_1, x_2, ... , and the values of x_n are mapped to values between 0 and 1.

FIG. 18 shows a case where independent TTT-SF values for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention are set to 'ReportConfigEUTRA' IE by applying SF values set in consideration of the existing terminal speed state.

Referring to FIG. 18, an independent TTT-SF value is set for each neighboring cell belonging to a specific cell type. The independent TTT-SF value for each neighboring cell belonging to a specific cell type is' MeasObjectEUTRA 'IE (1-4-1) or' ReportConfigEUTRA 'IE (1-4-2).

As shown in the figure, a 'cellTypesList' field in red is newly proposed in the 'ReportConfigEUTRA' IE. The field is designed to have different TTT-SF values for different PCI ranages with different cell types.

Similar to the above (1-2), the SF values set in consideration of the terminal speed state described in the present LTE standard can be reused as they are in the scheme 1-4-2 (1-4-2- One). The cell type list is shown in the following table.

CellTypesList
List of cell types having individual scaling factors applicable to a neighbouring cell (s) belonging to a specific cell type. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

FIG. 19 illustrates a case where a separate TTT-SF value is set for each neighboring cell belonging to a specific cell type according to an embodiment of the present invention, and another TTT-SF value is set in the 'ReportConfigEUTRA' IE.

Referring to FIG. 19, a method for setting an independent TTT-SF value for each neighboring cell belonging to a specific cell type, wherein the independent TTT-SF value for each neighboring cell belonging to a specific cell type is' MeasObjectEUTRA 'IE (1-4-1) or' ReportConfigEUTRA 'IE (1-4-2).

As shown in the figure, a 'cellTypesList' field in red is newly proposed in the 'ReportConfigEUTRA' IE. The field is designed to have different TTT-SF values for different PCI ranages with different cell types.

Similar to the above (1-2), the SF values may be separately set in consideration of the terminal speed state described in the present LTE standard in the above method (1-4-2) (1-4-2-2). The cell type list is shown in the following table.

CellTypesList
List of cell types having individual scaling factors applicable to a neighbouring cell (s) belonging to a specific cell type. The timeToTrigger in ReportConfigEUTRA is multiplied with this scaling factor.

Here, x_1, x_2, ... , and the values of x_n are mapped to values between 0 and 1.

(2) A method in which a base station transmits independent Treselection values to neighboring BSs to an idle mode UE will be described.

FIG. 20 illustrates a case where an independent Treselection value is set for each specific neighboring cell according to an embodiment of the present invention.

Referring to FIG. 20, in case (2-1) in which an independent Treselection value is set for each specific neighboring cell, in the LTE standard, the base station transmits a Treselection value to the idle mode terminal through SystemInformationBlock3 have.

In general, SIB3 includes common information for cell reselection regardless of intra-frequency / inter-frequency / inter-RAT cell reselection.

In the method (2-1) of the present invention, although the SIB is not limited to any SIB that can be received by the idle mode terminal, it is set to the SIB3 including the current Treselection value as an embodiment.

As shown in the drawing, a new 'cellIndividualInfoList' field represented in red in SIB3 is newly proposed. N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field.

In the 'cellIndividualInfo' field, 'cellIndividual-t-Reselection' field, which is an independent Treselection value for each neighbor cell, is set, and phyCellId and cellIndividual-t -ReselectionEUTRA are as shown in the following table.

phyCellId
Physical cell identity of a cell in neighbouring cell list. cellIndividual-t-ReselectionEUTRA
Cell individual parameter "TreselectionEUTRAN" applies to a specific neighbouring cell.

FIG. 21 illustrates a case where SF values set in consideration of an existing terminal speed are applied to independent Treselection-SF values for specific neighboring cells according to an embodiment of the present invention.

Referring to FIG. 21, a method 2-2 for setting an independent Treselection-SF value for each specific neighboring cell. Like the TTT-SF, in the current LTE standard, a 'speed-dependent' A scaling factor (SF) is applied.

When the idle mode terminal is high and medium mobility, sf-High value and sf-Medium value are multiplied by the Treslection value, respectively. Therefore, when the terminal is fast, it is possible to apply a smaller Treslection value than the original given Treslection value.

In the above method (2-2), the SF values set in consideration of the idle mode terminal speed state described in the LTE standard may be applied (2-2-1), and the SF values may be newly set (2-2-2) It is possible.

The SIB 3 includes the current Treselection-SF value as an example, regardless of the SIB that can be received by the idle mode terminal.

As shown in the drawing, a new 'cellIndividualInfoList' field represented in red in SIB3 is newly proposed. N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field.

In the 'cellIndividualInfo' field, 'cellIndividual-t-Reselection-SF' field, which is an independent Treselection-SF value for each neighbor cell, is set.

The added 'cellIndividual-t-Reselection-SF' field indicates a cell individual Treselection-SF value applied to a specific neighbor cell. For a particular neighbor cell, the SF value may be multiplied by the original Treselection value to set the TTT short.

Here, 'SpeedStateScaleFactors' IE, which is the SF values set in consideration of the terminal speed state shown in the LTE standard, is directly applied (2-2-1). Here, phyCellId and cellIndividual-t-ReselectionEUTRA-SF are shown in the following table.

phyCellId
Physical cell identity of a cell in neighbouring cell list. cellIndividual-t-ReselectionEUTRA-SF
Cell individual parameter "Speed dependent Scaling Factor for TreselectionEUTRAN"

FIG. 22 shows a case where SFs are newly set to independent Treselection-SF values for specific neighbors according to an embodiment of the present invention.

Referring to FIG. 22, when a new SF value is newly set (2-2-2), a new 'cellIndividualInfoList' field indicated in red in SIB3 is newly proposed.

N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field. In the 'cellIndividualInfo' field, 'cellIndividual-t-Reselection-SF' field, which is an independent Treselection-SF value for each neighbor cell, is set.

The added 'cellIndividual-t-Reselection-SF' field indicates a cell individual Treselection-SF value applied to a specific neighbor cell. For a particular neighbor cell, the SF value may be multiplied by the original Treselection value to set the TTT short.

Here, we use 'CellIndividualScaleFactors' which is newly defined IE related to scale factor (2-2-2). Here, phyCellId and cellIndividual-t-ReselectionEUTRA-SF are shown in the following table.

phyCellId
Physical cell identity of a cell in neighbouring cell list. cellIndividual-t-ReselectionEUTRA-SF
Cell individual parameter "Speed dependent Scaling Factor for TreselectionEUTRAN"

Here, x_1, x_2, ... , and the values of x_n are mapped to values between 0 and 1.

FIG. 23 illustrates a case where a Treselection value is set for each specific neighbouring cell according to an embodiment of the present invention.

Referring to FIG. 23, a method (2-3) for setting an independent Treselection value for each neighboring cell belonging to a specific cell type is not limited to any SIB that can be received by the idle mode terminal. However, It is assumed that SIB3 contains the current Treselection value.

As shown in the drawing, a new 'cellIndividualInfoList' field represented in red in SIB3 is newly proposed. N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field.

In the 'cellIndividualInfo' field, 'cellIndividual-t-ReselectionEUTRA' field, which is an independent Treselection value for each PCI range which is a specific cell type, is set. phyCellIdRange and cellIndividual-t-ReselectionEUTRA are shown in the table below.

phyCellIdRange
A ranage of physical cell identities in a neighbouring cell list. cellIndividual-t-ReselectionEUTRA
Cell individual parameter "TreselectionEUTRAN" applies to a specific neighbouring cell

FIG. 24 illustrates a case in which Treselection-SF values for specific neighbors according to an embodiment of the present invention are set using SF values set in consideration of existing terminal speeds.

Referring to FIG. 24, although it is not related to any SIB that can be received by the idle mode terminal in the method (2-4) for setting the independent Treselection-SF value for each neighboring cell belonging to a specific cell type, Set it to SIB3 which contains -SF value. In the above method (2-4), it is possible to consider a method (2-4-1) for applying and setting the SF values set in consideration of the existing terminal speed condition.

As shown in the drawing, a new 'cellIndividualInfoList' field represented in red in SIB3 is newly proposed. N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field.

In the 'cellIndividualInfo' field, 'cellIndividual-t-ReselectionEUTRA' field, which is an independent Treselection value for each PCI range which is a specific cell type, is set.

The added 'cellIndividual-t-Reselection-SF' field indicates a cell individual Treselection-SF value applied to a specific neighbor cell. For a particular neighbor cell, the SF value may be multiplied by the original Treselection value to set the TTT short.

Here, the 'SpeedStateScaleFactors' IE, which is the SF values set in consideration of the terminal speed state described in the LTE standard, is directly applied. PhyCellIdRange and cellIndividual-t-ReselectionEUTRA-SF are shown in the following table.

PhyCellIdRange
A ranage of physical cell identities in a neighbouring cell list. cellIndividual-t-ReselectionEUTRA-SF
Cell individual parameter "Speed dependent Scaling Factor for TreselectionEUTRAN"

FIG. 25 illustrates a case where SFs are newly set in consideration of existing terminal speeds for each Treselection-SF value for each specific neighboring cell according to an embodiment of the present invention.

Referring to FIG. 25, although the method of setting an independent Treselection-SF value for each neighboring cell belonging to a particular cell type does not matter to any SIB that the idle mode terminal can receive, Set it to SIB3 which contains -SF value. In the above method (2-4), it is possible to consider the case (2-4-2) in which additional SF values are newly set in consideration of the existing terminal speed condition.

As shown in the figure, a new 'cellIndividualInfoList' field represented in red in SIB3 is newly proposed.

N 'cellIndividualInfo' fields are set in the 'cellIndividualInfoList' field. In the 'cellIndividualInfo' field, 'cellIndividual-t-ReselectionEUTRA' field, which is an independent Treselection value for each PCI range which is a specific cell type, is set.

The added 'cellIndividual-t-Reselection-SF' field indicates a cell individual Treselection-SF value applied to a specific neighbor cell. For a particular neighbor cell, the SF value may be multiplied by the original Treselection value to set the TTT short.

Here we use the new defined Scale Factor IE, 'CellIndividualScaleFactors'. Here, phyCellId and cellIndividual-t-ReselectionEUTRA-SF are shown in the following table.

phyCellId
Physical cell identity of a cell in neighbouring cell list. cellIndividual-t-ReselectionEUTRA-SF
Cell individual parameter "Speed dependent Scaling Factor for TreselectionEUTRAN"

Here, x_1, x_2, ... , and the values of x_n are mapped to values between 0 and 1.

26 is a block diagram of a base station and a terminal according to an embodiment of the present invention.

26, a base station (or a terminal) according to the present invention includes a duplexer 2600, an RF receiver 2602, an ADC 2604, an OFDM demodulator 2606, a decoder 2608, A message processor 2610, a controller 2612, a message generator 2614, an encoder 2616, an OFDM modulator 2618, a DAC 2620, and an RF transmitter 2622.

26, the duplexer 2600 transmits a reception signal from an antenna to the RF receiver 2602 by a duplexing method, and transmits a transmission signal from the RF transmitter 2622 through the antenna.

The RF receiver 2602 converts a radio frequency (RF) signal from the duplexer 2600 into a baseband analog signal. The ADC 2604 converts the analog signal from the RF receiver 2602 into sample data and outputs it. The OFDM demodulator 2606 performs Fast Fourier Transform (FFT) on the sample data output from the ADC 2604 to output frequency-domain data.

The decoder 2608 selects data (burst data) of subcarriers to be actually received from the frequency-domain data from the OFDM demodulator 2606 and demodulates the selected data according to a predetermined modulation level (MCS level) demodulation, and decoding.

The message processing unit 2610 detects a predetermined unit of packet (e.g., MAC PDU) from the data from the decoder 2608, and performs header and error checking on the detected packet. At this time, if it is determined through the header inspection that the message is a control message, the message processing unit 2610 interprets the control message according to the prescribed standard and provides the result to the control unit 2612. That is, the message processor 2610 extracts various control information from the received control message and transmits the extracted control information to the controller 2612.

The control unit 2612 performs the process based on the information from the message processing unit 2610. Also, when the control unit 2612 needs to transmit a control message, the control unit 2612 generates the corresponding information and provides the information to the message generating unit 2614. The message generator 2614 generates a message with various kinds of information provided from the controller 2612 and outputs the message to the physical layer encoder 2616.

The encoder 2616 codes and modulates the data from the message generator 2614 according to a predetermined modulation level (MCS level). The OFDM modulator 2618 performs IFFT (Inverse Fast Fourier Transform) on the data from the encoder 2616 to output sample data (OFDM symbol). The DAC 2620 converts the sample data into an analog signal and outputs the analog signal. The RF processor 2622 converts an analog signal from the DAC 2620 into an RF (Radio Frequency) signal and transmits the signal through an antenna.

In the above-described configuration, the control unit 2612 controls the message processing unit 2610 and the message generating unit 2614 as a protocol control unit. That is, the controller 2612 may perform the functions of the message processor 2610 and the message generator 2614. In the present invention, these are separately configured to distinguish the respective functions. Accordingly, in the case of actual implementation, all of them can be processed by the control unit 2612, and only a part of them can be processed by the control unit 2612.

The operation of the base station and the terminal will be described below based on the configuration of FIG.

First, the controller 2612 reads the TTT and the Handover Trigger Threshold value from the generating or storing unit (not shown) to the neighboring base station, and provides the message to the message generator 2614. The message generator 2614 generates the corresponding message and outputs the generated message to the encoder 2616. Upon receiving the control message (IE) of the present invention from the message processing unit 2610, the control unit 2612 performs a corresponding process.

Alternatively, the controller 2612 may read information from the generating or storing unit (not shown) such as TTT, TTT-SF, Treselection, and Treselection-SF, ). The message generator 2614 generates a corresponding message and outputs the generated message to the encoder 2616.

When receiving a TTT, a TTT-SF, a Treselection, a Treselection-SF, or the like from the message processor 2610, the controller 2612 applies the information to the UE at handover or cell reselection .

Now, the performance analysis of the present invention will be described below. The hotzone cell referred to here is the same as the microcell.

27 is a diagram illustrating an environment for performance analysis according to an embodiment of the present invention.

27, using an LTE handover SLS (System Level Simulator) in which an arbitrary hotzone cell is deployed in the central Serving Sector of the cellular environment and the UE is moved as shown in the figure, to gain the benefit of the present invention Handover performance measurement.

As the main handover performance metric, HO Fail Ratio measurement was performed by adjusting TTT (Time-to-trigger) and CIO (Cell Individual Offset to HO Parameter).

Feature / Parameter Value / Description Bandwidth 10 MHz Duplexing FDD 3GPP Macro Cell Scenario Cell layout 57 sectors / 19 BSs Hotzone layout Minimum distance between UE
and cell site 30 m Antenna pattern 75-degree sectored beam Shadowing correlation between cells / sectors 0.5 / 1.0 Multipath delay profile Typical Urban Cell Radius 500 m Number of UEs per cell 20 Load Factor UL IoT depending on Load Facotr DL Load 50% -> UL IoT 5.0dB
DL Load 100% -> UL IoT 7.0dB Traffic model Full Buffer UE Speed 30 km / h, 120 km / h RSRP Measurement Measurement period 40 ms Sliding window size 5 samples L3 Filter Coefficient K = 4 Receiver diversity 2RX MRC X2 Latency & eNB processing 50 ms RRC Processing Delay 20 ms UE processors switching time 20 ms HO message sizes Measurement report: 184 bits; HO command: 288 bits;
HO confirm message: 112 bits Simulation Time 100 sec

Here, in order to see convergence for the worst case of the handover performance, the mobile speed of the terminal is assumed to be 120 km / h.

FIG. 29 is a graph showing a result of HO Fail Ratio when Load Factor 50% and UL IoT 5dB according to an embodiment of the present invention, FIG. 29 is a graph showing a load factor 100%, UL IoT 7dB , The HO Fail Ratio result is shown.

Referring to FIG. 28, since the HO Fail Ratio that can be accepted by the system operation definition is 2%, the performance graph shows that in the downlink 50% load environment, the TTT and the CIO from the macro- 160 ms and CIO = 1 to 3 dB is the optimal parameter. On the other hand, it is found that setting the TTT and the CIO to 0 to 80 ms and the CIO = 1 to 3 dB, respectively, in the macro-to-microroute environment is the optimum parameter.

In a 100% load environment, it is optimal to set the TTT and CIO of the macro to 40ms and the CIO to 1dB in the macro, while in the macro to micro environment, the TTT and the CIO are set to 0ms and CIO = 1 to 3dB It can be seen that setting is the optimum parameter.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

Claims (20)

A method of operating a base station in a wireless communication system,
Generating a message including a first TTT (time-to-trigger) value for at least one first neighbor base station and a second TTT value for at least one second neighbor base station;
And transmitting the message,
Wherein the message comprises information indicating the at least one second neighbor base station.
The method according to claim 1,
Wherein the information indicating the at least one second neighbor base station indicates a range of cell identities,
Wherein the cell identifier for the at least one second neighbor base station is different from the cell identifier for the at least one first neighbor base station.
The method according to claim 1,
Wherein the information indicating the at least one second neighbor base station is included in a MeasObjectEUTRA IE (information element).
The method according to claim 1,
Wherein the second TTT value is included in a ReportConfigEUTRA IE (information element).
The method according to claim 1,
Further comprising receiving information on the second TTT value from the at least one second neighbor base station.
A method of operating a terminal in a wireless communication system,
Receiving a message including a first time-to-trigger value for at least one first neighbor base station and a second TTT value for at least one second neighbor base station;
And checking a TTT value applied to a plurality of neighbor base stations based on the message,
Wherein the message comprises information indicating the at least one second neighbor base station.
The method of claim 6,
Wherein the information indicating the at least one second neighbor base station indicates a range of cell identities,
Wherein the cell identifier for the at least one second neighbor base station is different from the cell identifier for the at least one first neighbor base station.
The method of claim 6,
Wherein the information indicating the at least one second neighbor base station is included in a MeasObjectEUTRA IE (information element).
The method of claim 6,
Wherein the second TTT value is included in a ReportConfigEUTRA IE (information element).
The method of claim 6,
And transmitting a measurement report message for the at least one second neighbor base station to the serving base station based on the second TTT value.
A base station apparatus in a wireless communication system,
At least one processor for generating a message comprising a first time-to-trigger value for at least one first neighbor base station and a second TTT value for at least one second neighbor base station,
And a transmission / reception unit for transmitting the message,
Wherein the message comprises information indicating the at least one second neighbor base station.
The method of claim 11,
Wherein the information indicating the at least one second neighbor base station indicates a range of cell identities,
Wherein the cell identifier for the at least one second neighbor base station is different from the cell identifier for the at least one first neighbor base station.
The method of claim 11,
Wherein the information indicating the at least one second neighbor base station is included in a MeasObjectEUTRA IE (information element).
The method of claim 11,
And the second TTT value is included in a ReportConfigEUTRA IE (information element).
The method of claim 11,
Wherein the at least one processor is configured to receive information on the second TTT value from the at least one second neighbor base station.
A terminal apparatus in a wireless communication system,
A transceiver for receiving a message including a first TTT value for at least one first neighbor base station and a second TTT value for at least one second neighbor base station;
And at least one processor for determining a TTT value applied to a plurality of neighbor base stations based on the message,
Wherein the message comprises information indicating the at least one second neighbor base station.
18. The method of claim 16,
Wherein the information indicating the at least one second neighbor base station indicates a range of cell identities,
Wherein the cell identifier for the at least one second neighbor base station is different from the cell identifier for the at least one first neighbor base station.
18. The method of claim 16,
Wherein the information indicating the at least one second neighbor base station is included in a MeasObjectEUTRA IE (information element).
18. The method of claim 16,
And the second TTT value is included in a ReportConfigEUTRA IE (information element).
18. The method of claim 16,
Wherein the at least one processor is configured to send a measurement report message for the at least one second neighbor base station to the serving base station based on the second TTT value.

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