KR20150005417A - Methods and apparatuses for mobility information signaling - Google Patents

Abstract

The present invention relates to a mobility information signaling method in a heterogeneous network (HetNet) environment where various kinds of cells (for example, macro cells and small cell, etc) are mixed. In a control method of preventing a terminal which quickly moves in a heterogeneous network from being connected to a small cell in a base station, provided are an apparatus and a method which includes a step of receiving a first signal which includes at least one among the mobility information of a terminal, the history information of an idle condition, and a history information display information from the terminal, and a step of transmitting information included in the first signal to a target base station.

Description

METHOD AND APPARATUS FOR MOBILITY INFORMATION SIGNALING

The present invention relates to a mobility information signaling method in a heterogeneous network (HETNet) environment in which various types of cells (e.g., macrocells and small cells) are operated together.

The present invention provides a method for preventing a fast moving terminal from continuously using a small cell while moving quickly in a HetNet environment. That is, the present invention provides a method for preventing a terminal moving fast from using a small cell even if the terminal changes the base station. In addition, the present invention provides a method and apparatus for controlling handover of a terminal based on display information including mobility information of the terminal.

1 is a diagram illustrating an RRC Connection establishment procedure.
2 is a diagram illustrating a method for transmitting mobility information according to the present invention.
3 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
4 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, 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.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.

That is, the base station or the cell in this specification is interpreted as a comprehensive meaning indicating a partial region or function covered by BSC (Base Station Controller) in CDMA, NodeB in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.

Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) a device itself providing a megacell, a macrocell, a microcell, a picocell, a femtocell, or a small cell in relation to a wireless region, or ii) the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a megacell, a macrocell, a microcell, a picocell, a femtocell, a small cell, an RRH, an antenna, an RU, a low power node (LPN), a point, an eNB, Quot;

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-Advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In systems such as LTE and LTE-Advanced, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.

On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmission / reception points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multiplex transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiplex transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.

In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.

That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.

Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.

Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of a PDSCH, A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

A Hetnet in which several types of cells are mixed can be constructed in a single carrier or multicarrier environment including CA (carrier aggregation) case and non-CA case. Robust mobility between the macro cell base station and the small cell base station must be provided in order to effectively enable offloading of the macro base station. However, handover performance in HetNet environment is worse than environment where only macro base station exists. This problem is more serious in the case of a fast moving terminal. In the HetNet environment, the small cell is mainly aimed at offloading of slow moving terminals, and if a fast moving terminal avoids the use of small cells, the handover failure can be reduced.

In a conventional LTE (Long Term Evolution) network, a mobility state of a terminal is estimated by counting the number of movements for a predetermined period of time. The mobility state of the IDLE terminal counts cell reselections as the number of movements. The mobility state of the UE is IDLE parameters for estimating the moving velocity through a system information broadcast in the serving cell (T _{CRmax, CR_H} N, N _{CR _M)} is sent when the mobile terminal following the same basis in accordance with the 3GPP TS36.304 state Lt; / RTI >

- medium mobility state criterion: time period T _CRmax , the number of movements exceeds N _{CR _ M} and does not exceed N _{CR _ H}

- high mobility states by: the time period T _CRmax, the number of times for moving the neomeum N _{_ CR H}

The parameters (MobilityStateParametrs: t-Evaluation, n-CellChangeHigh, n-CellChangeMedium) for estimating the mobility state of the CONNECTED terminal are configured through a measurement configuration. The mobile station counts the handover instead of the cell reselection and performs the mobility state detection of the terminal specified in TS36.304. t-Evaluation corresponds to T _CRmax of _TS36.304 . n-CellChangeHigh corresponds to N _{CR _H} of TS36.304. n-CellChangeMedium is the N _{CR _M} of TS36.304.

On the other hand, it is difficult for the base station to accurately estimate the mobility state information of the terminal. In the IDLE state, since the RRC connection between the UE and the BS is released, the BS can not know the mobility state of the UE with respect to the IDLE UE. Therefore, it is difficult for the base station to estimate the mobility state of the terminal with respect to the normal terminal that repeats the IDLE and CONNECTED states.

For the base station which is difficult to estimate the mobility state information of the terminal, a scheme may be considered in which the IDLE terminal provides the mobility state information of the terminal to the base station during the RRC connection establishment. However, in this scheme, when the mobile station moves, the base station can not keep track of the mobile state of the mobile station. The base station can confirm only the information on the cell list that has been visited before the terminal is in the CONNECTED state and can not estimate the mobility state of the terminal with respect to the normal terminal that repeats the IDLE and CONNECTED states.

As described above, in the conventional HetNet environment, there is a problem that handover performance is degraded when a fast-moving terminal uses a small cell. However, since it is difficult to accurately estimate the mobility state of the terminal in the base station, it is difficult to prevent the terminal moving fast from using the small cell by grasping the mobility state of the terminal. In this case, even if the mobile station provides the mobility state information of the mobile station to the base station during connection establishment, for the base station which is difficult to estimate the mobility state information of the mobile station, if the macro base station is changed according to the mobile station, It is impossible to prevent the use of the small cell of the terminal moving fast in the changed base station, and the handover performance may again be deteriorated.

In order to solve the above-described problems, the present invention provides a method for continuously preventing a small cell from being used while a UE moving fast in a HetNet environment moves fast. That is, even if the terminal changes the base station, a method for preventing a fast moving terminal from using the small cell is provided. In addition, the present invention provides a method for updating a mobility state of a terminal after a RRC Connection connection is established.

The terminal can select an appropriate macro cell. Even if the terminal selects a small cell, the terminal can reselect a better cell while the terminal camp on the small cell. Since the terminal reselects an appropriate cell having the highest priority frequency, if the frequency is higher than the frequency priority of the small cell in the network and the frequency priority of the macro cell is broadcast, the terminal reselects the appropriate macro cell .

Terminal mobility information ( mobility information )

The terminal in the IDLE state capable of providing the terminal mobility information can transmit the terminal mobility information capable of estimating the mobile speed of the terminal during the RRC Connection setting in FIG. 1 to the eNB. The terminal mobility information may be the mobility state information estimated by counting cell reselections for a predetermined period of time by the IDLE terminal.

The terminal mobility information may be terminal mobility state information calculated by improving existing terminal mobility state information considering a small cell having a smaller cell size than a macro cell. One example of the improved terminal mobility state information may be terminal mobility state information calculated through a cell specific weight. (Eg, macro-macro, macro-small, and so on) when calculating the terminal mobility state, or may be information obtained by counting the number of movements by assigning weights according to the cell size (or the cell type or the movement type (intra-eNB cell or intra- For small-macro, small-small reselection, small cell-related reselection counts less than macrocell). Another example of the improved terminal mobility state information may be terminal mobility state information that counts the number of movements only for macro cells. That is, the terminal mobility state information may not be counted for the small cell when calculating the terminal mobility state. Alternatively, the terminal mobility information that can estimate the terminal's movement speed during the RRC Connection setup may be the _reselected cell history information during the last time period T _CRmax . The _reselected history information during the last time period T _{CRmax could contain} up to four or eight or sixteen previous visited cell information through the Last Visited Cell List. The current _TCRmax value can be selected from among 30 seconds, 60 seconds, 120 seconds, 180 seconds, and 240 seconds. The previous visited cell information may include a global cell ID, a cell type, a time in stay in cell (IE) information element, and the like.

The base station can transmit to the terminal an indication indicating that it can receive the terminal mobility information or information for requesting the terminal mobility information. The information indicating that the terminal mobility information can be received or the information for requesting the terminal mobility information can be broadcast through the system information. Alternatively, if the base station broadcasts cell-specific information for improving and calculating the terminal mobility state through the system information, the terminal can know that the base station can receive the terminal mobility information. Alternatively, the indication indicating that the terminal mobility information can be received or the information for requesting the terminal mobility information may be included in the RRC Connection Establishment message during the RRC Connection establishment procedure and transmitted to the terminal.

Alternatively, the indication indicating that the UE mobility information can be received or the information for requesting the UE mobility information may be included in the UE information request message, transmitted to the UE, and received through the UE Information response message.

Alternatively, the base station may not transmit to the terminal an indication indicating that it can receive the terminal mobility information or information for requesting the terminal mobility information.

1 is a diagram illustrating an RRC Connection establishment procedure.

The UE can transmit the UE mobility information to the BS by including it in the RRC Connection Setup Complete message. For example, the MS can send high mobility state information to the RRC Connection Setup Complete message. That is, when the terminal is in a high mobility state prior to the establishment of the RRC Connection and / or received information indicating that it can receive terminal mobility information from the network or information for requesting the terminal mobility information, the terminal includes high mobility state information And send an RRC Connection Setup Complete message. The RRC Connection Setup Complete message may be configured as follows.

As another example, the UE can transmit the mobility state information of the UE in the RRC Connection Setup Complete message.

The RRC Connection Setup Complete message may be configured as follows, for example.

In another example, if the terminal mobility information is _composed of _reselected history information during the last time period T _CRmax , the terminal _transmits indication information indicating that the _reselected history information is available during the last time period T _CRmax to the RRC Connection Setup Complete message Can be included in.

The RRC Connection Setup Complete message may be configured as follows, for example.

Upon receiving the mobility information of the mobile station during the RRC connection establishment procedure, the base station determines whether the mobile station that moves quickly based on the mobility information of the received mobile station does not use the small cell layer (eg, To stay). An example of this is that the network may not have a measurement configuration for a small cell (eg, does not have a measurement configuration for a small cell frequency measurement object) for a terminal that is highly mobile. As another example for keeping the UE moving fast based on the mobility information not to use the small cell layer, the base station may configure the measurement period for the small cell to be long or perform the measurement after a predetermined time for the small cell Can be configured. As another example of keeping the UE moving fast based on the mobility information not to use the small cell layer, even when the BS performs the measurement configuration for the small cell and receives the report from the UE, Quality problem, macrocell radio link failure), it may not decide handover to the small cell.

Macro cell Handover

When a mobile station with high mobility information moves between macro cells, it can perform handover to another macro cell base station. The following method can be used to avoid using a small cell of a received MS with high mobility information when performing a handover to a macro cell BS.

Method 1 . Handover  Ready information ( HandoverPreparationInformation ) Message contains terminal mobility information

During handover preparation, the source eNB may use the HandoverPreparationInformation message to convey the RRC information to be used by the target eNB. The source eNB may include the mobility information of the terminal in the HandoverPreparationInformation message to the target eNB so that the terminal that moves even after the handover in the target cell does not use the small cell layer.

For example, the mobility information of the UE can be included in the AS-Context information of the HandoverPreparationInformation message. The HandoverPreparationInformation message and the AS-Context information may be configured as follows, for example.

The base station, which has received the mobility information of the mobile station during the handover preparation, determines that the mobile station which moves rapidly based on the mobility information of the mobile station received after the handover does not use the small cell layer (eg, To stay in the cell layer). As an example of this, the network may not make a measurement configuration for a small cell (i.e., does not make a measurement configuration for a small cell frequency measurement object) with respect to a terminal received with high mobility. As another example for keeping the UE moving fast based on the mobility information not to use the small cell layer, the base station may configure the measurement period for the small cell to be long or perform the measurement after a predetermined time for the small cell Can be configured. As another example of keeping the UE moving fast based on the mobility information not to use the small cell layer, even when the BS performs the measurement configuration for the small cell and receives the report from the UE, Quality problem, macrocell radio link failure), it may not decide handover to the small cell.

If the terminal mobility information is _composed of _reselected history information during the last time period T _CRmax , the base station, which has received the indication information indicating that the _reselected history information is available during the terminal's last time period T _CRmax during handover preparation, After completion of the handover, the MS requests the _reselected history information during the last time period T _CRmax of the UE's IDLE state in an RRC message (for example, a UE Information request message), and transmits an RRC message ) To receive the _reselected history information during the last time period T _CRmax of the terminal's IDLE state. The base station that has completed the handover can estimate the mobility state of the UE using the visited cell information in the Connected state included in the UE History Information included in the handover request message. If necessary, the base station requests _reseated history information during the last time period T _CRmax of the UE in an _RLE message (e.g., UE Information request message) to the UE in the IDLE state, and transmits an RRC message (e.g., UE Information response message) The UE can receive the _reselected history information during the last time period T _CRmax of the UE in the IDLE state and combine it with the visited cell information included in the UE History Information included in the handover request message to estimate the mobility state of the UE . For example, in a handover-initiated base station, the visited cell information included in the UE History Information included in the handover request message includes only one cell information, and the time in the in-cell time is T _CRmax , the mobility state of the UE is low, so it is possible to estimate the mobility state of the UE to be in a low state without having to request and receive the _reselected history information during the last time period T _CRmax of the IDLE state. In another example, the handover- _initiated base station determines that the connected cell information included in the UE History Information included in the handover request message includes cell information larger than N _{CR_H} , Is less than T _CRmax , since the mobility state of the terminal is a high mobility state, it is possible to estimate the mobility state of the terminal without requiring the terminal to request _reselected history information during the last time period T _CRmax of the IDLE state have. Another example is the handover of the base station visited cell information in the Connected state includes the UE History Information contained in the handover request message is less than N _{CR _H} or N _{CR _M,} the sum of the cells in the time spent in each cell _Is greater than T _CRmax , the UE requests the _reselected history information during the last time period T _CRmax of the IDLE state with the RRC message (for example, the UE information request message), and transmits an RRC message Received history information during the last time period T _CRmax of the terminal, and combines with the visited cell information in the connected state included in the UE History Information to estimate the mobility state of the terminal.

Method 2 . Handover  Request message ( handover request ) Contains terminal mobility information

The source eNB may send a Handover request message to the target eNB to request resource preparation for handover. The source eNB may include the mobility information of the mobile station in the handover request message to the target eNB so that the mobile station that moves rapidly after the handover in the target cell does not use the small cell layer. For example, the mobility information of the UE may be included in the UE history information of the Handover request message. Up to Release-11, the conventional UE History Information could include up to 16 previous visited cell information through the Last Visited Cell List. The previous visited cell information includes a global cell ID, a cell type, and an in-cell time information IE.

The previous visited cell information on the UE history information including the mobility information of the UE may be configured as follows, for example.

Alternatively, if the terminal mobility information comprises _reselected history information during the last time period T _CRmax , the previous visited cell information on the UE history information may include the reselected cell information prior to the RRC Connection establishment .

For example, before handover, the BS may receive indication information indicating that the _reselected history information is available for the last time period T _CRmax from the UE through the RRC Connection Setup Complete message. Then, the terminal requests the _reselected history information during the last time period T _CRmax of the terminal's IDLE state through the RRC message (e.g., UE Information request message), and transmits the _reselected history information to the terminal through the RRC message IDLE state of the last time period T _CRmax . When the source base station determines handover according to the terminal movement, the source base station transmits the IDLE state last time period T _CRmax received from the terminal to the last visited cell list included in the UE history information element included in the handover request message, (Visited cell list). The last visited cell list included in the UE history information information element is added to the top of the list with the most recent information. Likewise, the visited cell list included in the reselected history information during the IDLE state last time period T _CRmax may be added to the top of the list. For example, if the source base station experiences handover and includes previous visited cell information in the connected state, the previous visited cell information of the connected state, which is the latest information on the _reselected history information during the last time period T _CRmax of the IDLE state, Most are added.

Alternatively, the mobility information of the UE can be transmitted by including a new information element in the Handover request message.

Upon receiving the mobility information of the mobile station through the handover request message, the base station determines that the mobile station which moves rapidly based on the mobility information of the mobile station received after the handover does not use the small cell layer So as to stay in the macro cell layer). An example of this is that the network may not have a measurement configuration for a small cell (eg, does not have a measurement configuration for a small cell frequency measurement object) for a terminal that is highly mobile. As another example for keeping the UE moving fast based on the mobility information not to use the small cell layer, the base station may configure the measurement period for the small cell to be long or perform the measurement after a predetermined time for the small cell Can be configured. As another example of keeping the UE moving fast based on the mobility information not to use the small cell layer, even when the BS performs the measurement configuration for the small cell and receives the report from the UE, Quality problem, macrocell radio link failure), it may not decide handover to the small cell.

Method 3 . RRC Connection Reconfiguration Complete  Including terminal mobility information through message

To perform the handover, the target eNB sends a Handover Request Acknowledge message containing the RRC Connection Reconfiguration message to be delivered to the UE to the source eNB. The RRC Connection Reconfiguration message including mobilityControlInformation is sent to the UE by the source eNB.

If the UE successfully accesses the target cell, the UE sends an RRC Connection Reconfiguration Complete message to the Node B to confirm handover. The mobile station may transmit the RRC Connection Reconfiguration Complete message including the mobility information of the mobile station so that the mobile station that moves rapidly after the handover in the target cell does not use the small cell layer.

An example of the RRC Connection Reconfiguration Complete message may be configured as follows.

Another example of the RRC Connection Reconfiguration Complete message may be configured as follows.

The RRC Connection Reconfiguration message including the mobility information of the terminal in the RRC Connection Reconfiguration Complete message includes information for requesting the terminal mobility information or an indication indicating that the base station can receive the terminal mobility information can do. An indication indicating that the base station can receive the terminal mobility information or information for requesting the terminal mobility information may be generated by the target cell. As another example, an indication that the base station can receive the terminal mobility information or information to request the terminal mobility information may be generated by the source cell. The UE can only confirm the RRC Connection Reconfiguration message including the mobilityControlInformation or the RRC Connection Reconfiguration message including the information for requesting the UE mobility information to indicate that the BS can receive the UE mobility information, Only the above-described terminal mobility information can be included in the target cell only when the RRC Connection Reconfiguration Complete message is sent.

Alternatively, the base station may not transmit to the terminal an indication indicating that it can receive the terminal mobility information or information for requesting the terminal mobility information.

Method 3 may be provided in combination with Method 1 or Method 2 to trigger receipt of mobility information in a handover, or may be provided independent of Method 1 or Method 2.

In another method, a method 3 is a method in which when a handover is generated after a time when a terminal maintains Connected state without changing a base station and the terminal mobility information is estimated to have changed (high mobility → low mobility) , Or when the mobile station continues handover to another base station after establishing an RRC connection with the base station in a low mobility state and it is estimated that the base station mobility information is changed (low mobility → high mobility) in the base station. That is, when the terminal mobility state is changed, the base station can use the method 3 to obtain the latest mobility information of the terminal.

Figure 2 shows the delivery procedure according to method 3;

2 is a diagram illustrating a method for transmitting mobility information according to the present invention.

Upon receiving the mobility information of the UE through the RRC Connection Reconfiguration Complete message, the BS determines that the UE moving fast based on the mobility information of the UE received after the handover does not use the small cell layer (e.g., So as to stay in the macro cell layer). An example of this is that the network may not have a measurement configuration for a small cell (eg, does not have a measurement configuration for a small cell frequency measurement object) for a terminal that is highly mobile. As another example for keeping the UE moving fast based on the mobility information not to use the small cell layer, the base station may configure the measurement period for the small cell to be long or perform the measurement after a predetermined time for the small cell Can be configured. As another example of keeping the UE moving fast based on the mobility information not to use the small cell layer, even when the BS performs the measurement configuration for the small cell and receives the report from the UE, Quality problem, macrocell radio link failure), it may not decide handover to the small cell.

Method 4 Handover  If for some time Small cell  Exclusion from use

When the UE performs handover, the Node B determines that the UE having completed the handover for a predetermined time after the handover or the UE having the high mobility state does not use the small cell layer (e.g., To stay in the macro cell layer). To accomplish this, when the handover is completed, a timer is started to exclude use of the small cell. When the timer for excluding the use of the small cell for a certain period of time after the handover has expired, the base station can cancel the measure for preventing the terminal from using the small cell layer. If the handover occurs before the timer for expiring the use of the small cell for a certain period of time after the handover has expired, the target base station restarts the timer for excluding the use of the small cell for a certain period of time after the handover.

The timer for excluding the use of the small cell for a predetermined time after the handover may be provided in the handover request message by the source base station. Alternatively, the timer for excluding the use of the small cell for a predetermined time after the handover may be determined by the target base station.

Method 5  Measure In reporting  Contains speed information

The base station may include the terminal mobility information in a measurement report message so that the fast moving terminal does not use the small cell layer. For example, the mobility information of the UE can be included in measurement results (MeasResults) included in a measurement report message. The measurement results (MeasResults) information may be configured as follows, for example.

The base station may include information for requesting terminal mobility information to the measurement configuration (MeasConfig) information included in the RRC Connection Reconfiguration message in order for the terminal to transmit the terminal mobility information in the measurement report message. Alternatively, the base station may not include information for requesting terminal mobility information in the measurement configuration (MeasConfig) included in the RRC Connection Reconfiguration message.

The base station receiving the mobility information of the terminal through the measurement reporting message can maintain the fast moving terminal not to use the small cell layer (for example, stay in the macro cell layer without making a handover decision to the small cell).

Mobility change handling

The base station receiving the mobility information of the mobile station during the RRC Connection establishment procedure can update the mobility state when the mobility state of the received mobile station is changed. The following methods can be used.

Method 6 . Use high mobility state timer

The base station that receives the mobility information of the mobile station during the RRC connection setup, when the mobile station receives a mobility state in which the mobile station moves at a high speed, does not use the small cell layer (e.g., To stay in the macro cell hierarchy). Also, the terminal can keep the small cell layer from being used until the timer for keeping the terminal from using the small cell layer is ended. For this purpose, a network is another example of not allowing measurement of a small cell for a UE received with high mobility or keeping a fast moving UE not to use a small cell layer. Or may be configured to perform measurement after a predetermined time with respect to the small cell. As another example of keeping the UE moving fast based on the mobility information not to use the small cell layer, even when the BS performs the measurement configuration for the small cell and receives the report from the UE, Quality problem, macrocell radio link failure), it may not decide handover to the small cell.

If a handover occurs to the RRC Connected UE before the timer for keeping the UE from using the small cell layer according to the high mobility state described above expires, the source base station transmits mobility information (e.g., The terminal mobility information of Method 1 or Method 2, or the _reselected history information during the IDLE state last time period T _CRmax ).

If the timer for keeping the mobile station from using the small cell layer expires according to the high mobility state for the RRC Connected mobile station, the base station can update or remove the mobile station mobility information. And can cancel the measure to prevent the terminal from using the small cell layer. If the terminal mobility information is updated or removed in a state that is not a high mobility state, the mobile station may not transmit the mobility information even if a handover occurs, because the timer for keeping the terminal from using the small cell layer has expired.

The timer for keeping the terminal from using the small cell layer according to the high mobility state may be transmitted together with the mobility state information of the terminal. Alternatively, a timer for keeping the terminal from using the small cell layer according to the high mobility state may be preconfigured in the base station and may be started when the base station receives the mobility state information of the terminal

Method 7 . From the terminal, Signaling  reception

If the mobility of the UE including the high UE mobility information is low after the lapse of a predetermined period of time during the RRC Connection setup, the base station does not use the small cell hierarchy so that the UE can use the small cell hierarchy It is possible to cancel the above-mentioned measures. To this end, the base station can receive the mobility information of the mobile station by sending signaling for requesting the mobility information to the mobile station. As an example of requesting mobility state signaling from the UE, signaling for requesting the UE mobility information may use a UE Information Request message. Then, the UE can use the UE Information Response message as a message for transmitting the UE mobility information to the BS. For example, the UE information request message including the indication of the mobility state request of the UE is transmitted and the mobility state information of the UE (the above-described high mobility information or mobility stateInfo) can be received through the UE Information Response message. In another example, the UE transmits a UE Information Request message including a _reselected history information request indication during the last time period T _CRmax of the IDLE state, and _reselects the UE in the UE ID Response state during the last time period T _CRmax And can receive history information (visited cell list). As another example of requesting mobility state signaling from the MS and receiving MS mobility information, signaling for requesting MS mobility information may use an existing RRC message or a new RRC message. The message for transmitting the terminal mobility information to the base station may use an existing RRC message or a new RRC message.

Alternatively, the RRC Connected UE may send the changed UE mobility information to the BS when it detects the UE mobility information sent to the BS during the RRC Connection setup, regardless of whether the BS requests the mobility information to the MS. When the base station receives the changed terminal mobility information (e.g., high mobility → low mobility), the base station can cancel the above measures to prevent the terminal from using the small cell layer. A message for the UE to send the UE mobility information to the base station may use an existing RRC message (eg, a measurement report or a UE information response message or a UL information transfer message) or a new RRC message.

During the RRC connection establishment, a terminal that provides terminal mobility information (e.g., medium terminal mobility state, normal terminal mobility state or terminal mobility information with a slow rate, RRC Connection setting including high mobility information, etc.) If it is estimated that the mobile station has changed to the mobile state, the base station can maintain the terminal having the high mobility state not to use the small cell layer (for example, stay in the macro cell layer without making a handover decision to the small cell). To this end, the base station can receive the mobility information of the mobile station by sending signaling for requesting the mobile station mobility information to the mobile station before handover, during handover, or after handover. As an example of the signaling for requesting the terminal mobility information during handover, the terminal mobility information request may be provided through the RRC Connection Reconfiguration message and the terminal mobility information through the RRC Connection Reconfiguration complete message. Alternatively, the base station may be configured to base the UE history information (e.g., UE History Information including up to Release-11 or UE history information including UE mobility information) received from the previous base station before handover, The mobility state change of the terminal can be estimated.

Alternatively, when the RRC Connected UE detects the UE mobility information and the UE mobility information sent during the establishment of the RRC Connection, regardless of the mobility information request from the base station to the UE, the UE can transmit the changed UE mobility information to the BS. When the base station receives the changed terminal mobility information (e.g., low mobility → high mobility), the base station can keep the terminal from using the small cell layer. A message for the UE to send the UE mobility information to the base station may use an existing RRC message (eg, a measurement report or a UE information response message or a UL information transfer message) or a new RRC message.

As described above, the present invention provides a method for continuously preventing a small cell from being used while a fast moving terminal moves rapidly in a HetNet environment, thereby continuously preventing use of a small cell in a fast moving terminal, There is an effect of preventing falling. In addition, when the mobility of the terminal is changed, a method of updating the mobility is provided, thereby effectively performing off-loading based on the terminal mobility.

3 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

3, the base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 controls the overall operation of the base station according to a method for continuously preventing the small cell from being used while the terminal moving fast in the HetNet environment necessary for performing the above-described present invention moves fast.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

4 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

4, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiving unit 1110 receives downlink control information, data, and messages from the base station through the corresponding channel.

In addition, the controller 1120 controls the overall operation of the terminal according to a method for continuously preventing the small cell from being used while the terminal moving fast in the HetNet environment necessary for carrying out the present invention described above moves fast.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through the corresponding channel.

The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and portions of the standard documents are added to or contained in the scope of the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (1)

A method for controlling a terminal in a heterogeneous network environment such that a base station moves rapidly in a heterogeneous network environment,
Receiving, from the terminal, a first signal including at least one of mobility information of the terminal, history information of an idle state, and history information display information; And
And transmitting information contained in the first signal to a target base station.

Images