KR20150124046A - Apparatus and method of small cell discovery reference signal transmission and reception - Google Patents

Abstract

Provided in the present invention are a device and a method for setting a downlink reference signal for detecting a random cell formed by a random base station/evolved Node-B/Remote Radio Head/Radio Unit of a terminal in a 3GPP LTE/LTE-A wireless mobile communications system. The method for a terminal to estimate on/off state of small cell comprises the following steps of: receiving a discovery signal (DRS) from the base station; and estimating on/off status of a small cell based on the PSS, SSS, CRS and CSI-RS of the discovery signal.

Description

TECHNICAL FIELD [0001] The present invention relates to a small cell discovery reference signal transmission and reception method, and a small cell discovery reference signal transmission and reception method.

The present invention proposes a downlink reference signal setting method for detecting an arbitrary cell formed by an arbitrary base station / eNB / RRH / RU in a 3GPP LTE / LTE-A wireless mobile communication system. In particular, as a method for reducing power consumption of a base station / eNB / RRH / RU and reducing interference to neighboring cells, a corresponding cell is turned on (active state) or turned off and a method of establishing a downlink reference signal for cell detection or cell discovery of a UE when a semi-static or dynamic cell on / off mechanism is supported.

In this regard, in the present invention, especially, a small cell detection / discovery reference signal configuration according to application of semi-static or dynamic small cell on / off in various types of small cell base station / eNB / RRH / Although it focuses on the method, it is clear that the same concept can be applied to cells of various sizes and various types as well as small cells.

A method for estimating a small cell on / off state according to an embodiment of the present invention includes: receiving a discovery signal (DRS) from a base station; And estimating the small cell on-off state based on PSS, SSS, CRS and CSI-RS of the discovery signal.

1 is a diagram showing an example of a deployment scenario of a small cell in [1].
2 is a diagram illustrating an example of a small cell deployment scenario.
3 is a diagram illustrating an example of a small cell deployment scenario # 1.
4 is a diagram illustrating an example of a small cell deployment scenario # 2a.
5 is a diagram illustrating an example of a small cell deployment scenario # 2b.
6 is a diagram illustrating an example of a small cell deployment scenario # 3.
7 is a diagram illustrating an example of a mapping cyclic prefix (CRC) preamble.
8 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
9 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, in the present specification, a base station or a cell has a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, Node-B 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, 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 a transmission / reception point of a signal transmitted from a transmission / reception point, and the 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 transmit and receive 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 multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple 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.

Various techniques for applying various CoMP technologies with macro cells formed by high power eNB in 3GPP LTE / LTE-A rel-11 system and small cells formed by low power RRH connected with corresponding high power eNBs Various interference control techniques have been proposed in heterogeneous network scenarios where pico cells or micro cells overlap with macro cells to support hot spots or coverage holes. In 3GPP LTE / LTE-A rel-12, various small cell enhancement techniques are being researched.

The following describes a small cell deployment scenario to which the proposals described in the present invention can be applied.

1 is a diagram showing an example of a deployment scenario of a small cell in [1].

FIG. 1 shows a general picture in a case where a small cell and a macro cell are coexisted. In FIGS. 2 to 6, the presence or absence of macro coverage, whether the corresponding small cell is for outdoor use or indoor use, Whether they are sparse or dense, or whether they use the same frequency spectrum as the macro in terms of spectrum.

2 is a diagram illustrating an example of a small cell deployment scenario.

FIG. 2 shows a typical representative picture of the scenario of FIG. 3 to FIG. 6. Explanations of the respective scenarios will be described with reference to the respective scenario drawings.

3 is a diagram illustrating an example of a small cell deployment scenario # 1.

Scenario 1 is a co-channel deployment scenario for small cells and macro in the presence of an overlaid macro and is an outdoor small cell scenario.

4 is a diagram illustrating an example of a small cell deployment scenario # 2a.

Scenario 2a is a deployment scenario in which small cells and macros use different frequency spectrum in the presence of an overlaid macro and is an outdoor small cell scenario.

5 is a diagram illustrating an example of a small cell deployment scenario # 2b.

Scenario 2b is a deployment scenario in which small cells and macros use different frequency spectrum in the presence of overlaid macros and is an indoor small cell scenario.

6 is a diagram illustrating an example of a small cell deployment scenario # 3.

Scenario 3 is an indoor small cell scenario with no macro coverage.

<Small cell discovery related>

In order to detect any cell formed by an arbitrary base station / eNB / RU / RRH in an existing 3GPP LTE / LTE-A system (rel-11 or below system), PSS / SSS And CRS were used. Thus, in a base station / eNB / RU / RRH constituting a certain cell, a PSS / SSS is transmitted through a 0/5 downlink subframe in case of FDD according to a frame structure type (TDD / FDD) In the case of TDD, the PSS / SSS is transmitted through the 1/6 downlink subframe and the CRS is defined to be transmitted in all the downlink subframes configured.

However, research on various small cell deployment scenarios has been carried out through the study of 3GPP LTE / LTE-A rel-12. As a research area related to this, a small cell on / off operation plan and related small cell discovery procedure, and the need for a new small cell discovery procedure based on a new reference signal has been raised in addition to the existing PSS / SSS and CRS based small cell discovery methods.

Extract the contents of 3GPP RAN1 TR in relation to the corresponding small cell on / off and small cell discovery and attach it through appendix [1] TR36.872.

In this regard, the downlink reference signal and SS (synchronization signal) related information defined in the 3GPP LTE / LTE-A system are attached through appendix [2] TS36.211.

In this way, when a large number of small cells are overlapped with an arbitrary macro cell coverage, the overall system throughput is increased through cell splitting gain. However, interference between small cells and macro cells and increase of system power consumption And an increase in the maintenance cost. In particular, even when there is no UE connected in the corresponding small cell coverage, the small cell base station / eNB / RU / RRH continuously transmits the downlink signal including the PSS / SSS and the PBCH or CRS, / eNB / RU / RRH, as well as unnecessary interference to data transmission / reception in the adjacent cell.

In order to solve this problem, there is a need to support a small cell on / off operation for switching to a small cell base station / eNB / RU / RRH off mode / state according to the number of terminals connected to a small cell or the presence or absence of a terminal have. However, if the small cell on / off operation is supported, a cell discovery / measurement based on the existing PSS / SSS and CRS is performed to support the cell measurement / discovery of the UE even in the corresponding small cell off state, ) Based cell discovery / measurement procedure. In this case, a combination of PSS / SSS + CRS or a combination of PSS / SSS + CSI-RS or a combination of PSS / SSS + CSI-RS for measurement / discovery of a cell formed by a rel- A new DRS can be defined as a combination of CSI-RSs. However, when the new DRS is defined, the reference signal to be received by the UE for cell measurement / discovery in the on state and off state of the corresponding small cell may be changed, It is necessary to indicate the state of the cell (on state or off state) to the UE.

The present invention proposes a method for implicitly indicating the state of a corresponding small cell based on DRS in a small cell deployment scenario in which macro cells and a plurality of small cells are overlapped.

7 is a diagram illustrating an example of a mapping cyclic prefix (CRC).

In the existing 3GPP LTE / LTE-A rel-11 and below systems, the frame structure type 1 (FDD system) is used for cell discovery / synchronization and cell measurement in the base station / eNB / RU / ), The PSS is transmitted through the first OFDM symbol of the first slot and the 11th slot of every 10 ms radio frame, and the SSS is transmitted through the second OFDM symbol (i.e., the OFDM symbol immediately before the PSS) at the end of the same slot. In case of the frame structure type 2 (TDD system), the PSS is transmitted through the third OFDM symbol of the second subframe 1 and the seventh subframe 6 of the 10 ms radio frame, and the PSS is transmitted at the end of the second slot and the eleventh slot SSS is transmitted through the OFDM symbol. The UE performs time / frequency synchronization and cell ID detection on the downlink signal based on the PSS / SSS based on the received PSS / SSS, receives the MIB through the PBCH, and obtains the antenna port information attached to the corresponding base station. In addition, the base station has to transmit a CRS (cell-specific reference signal) in all downlink subframes in order to perform the cell measurement of the UE according to the number of the installed antenna ports as shown in FIG. 7 below. However, in the downlink subframe set with the MBSFN subframe, the corresponding CRS is transmitted only through the first OFDM symbol of the first slot or the second OFDM symbol.

The UE performs detection / synchronization and measurement for an arbitrary base station / cell by receiving the PSS / SSS and the CRS.

Accordingly, the UE connected to the corresponding base station receives the CRS transmitted through the corresponding downlink subframe for a predetermined time, measures the RSRP / RSRQ and reports it to the base station. Based on the measured RSRP / RSRQ, mobility management procedure and addition of secondary serving cell for carrier merging. Also, since the CRS transmitted by the corresponding base station is also used for channel measurement for determination of a handover target base station according to movement of a terminal connected to a neighbor base station and channel measurement for cell selection / reselection of idle terminals, The corresponding base station has to always transmit the CRS through all the downlink subframes even if there is no terminal connected thereto.

However, as described above, when a plurality of small cells are overlapped with a macro cell, it is often the case that no terminal is connected to a corresponding small cell. In this case, Downlink signals such as PSS / SSS or PBCH may unnecessarily interfere with macro cells or adjacent small cells. In addition, unnecessary power consumption always occurs in the corresponding small cell base station / eNB / RU / RRH in order to transmit CRS through each downlink subframe.

As a method to solve this problem, a semi-static or dynamic small cell on / off method of turning off a corresponding small cell when there is no terminal connected to any small cell or there is no data traffic is discussed. SSS, CRS, or other downlink signal through dynamic switching of on / off mode to subframe level or 10ms radio frame level for any cell or semi-static on / off mode switching. There is a need for a small cell on / off operation that supports off mode operation without channel transmission. In this case, when a corresponding small cell cell is applied with the corresponding dynamic or semi-static small cell on / off operation, when the corresponding small cell is in the off state, the CRS for the downlink channel measurement is not transmitted in all downlink subframes Therefore, it is necessary to define a new DRS and define a new cell discovery / measurement procedure based on the new DRS to ensure discovery performance of the UE for the corresponding small cell. Accordingly, a rel-12 base station A new DRS can be defined as a combination of PSS / SSS + CRS or a combination of PSS / SSS + CSI-RS or a combination of PSS / SSS + CRS + CSI-RS.

In the present invention, when a new type of DRS is defined for cell discovery / measurement of a UE, a method of implicitly indicating a state (on state vs. off state) of the corresponding cell based on the DRS is proposed do.

Method 1. Indication method based on relative position of PSS and SSS

When a newly defined DRS is transmitted in an arbitrary rel-12 base station / cell supporting small cell on / off, the relative position of an OFDM symbol to which PSS and SSS are transmitted according to an on state or an off state is defined differently, state to the UE. As an example of this, it is possible to define the transmission order of the PSS and the SSS and the OFDM symbols to be switched in the ON state and the OFF state. For example, in the case of the PSS / SSS position that constitutes the newly defined DRS, the cell is defined to follow the existing PSS / SSS position when the cell is on state, and when the cell is in the off state, the position of the PSS and SSS is reversely switched Can be defined. That is, the PSS and the SSS newly constituting the DRS newly defined in an on-state in an arbitrary FDD cell transmit the PSS through the last OFDM symbol of the first slot and the 11th slot of the 10-ms radio frame, SSS is transmitted through the second OFDM symbol from the last (i.e., the OFDM symbol immediately before the PSS), and when the DRS is configured in the off state, the SSS is transmitted through the last OFDM symbol of the first slot and the 11th slot of the 10ms radio frame And defines that the PSS is transmitted through the second OFDM symbol (i.e., the OFDM symbol immediately before the SSS) at the end of the same slot, thereby defining the state of the corresponding terminal to determine the state of the corresponding cell. In TDD cell, it is also possible to define DRS by combining the positions of PSS and SSS according to on state and off state. However, if the location and period of the OFDM symbol for transmission of the PSS and the SSS constituting the newly defined DRS are defined differently from the location and period of the OFDM symbol for transmitting the PSS / SSS defined in the existing system described above It is clear that the concept of distinguishing the state of a corresponding cell can be applied by mutually switching the position of the PSS / SSS proposed by the present method.

Alternatively, when DRS is configured, the positions of OFDM symbols allocated for transmission of PSS and SSS in on state and off state are defined differently, or symbol timing gap between PSS and SSS is defined differently, The state of the corresponding cell can be determined based on the timing gap between the PSS and the SSS. Specifically, when a PSS / SSS is transmitted based on a 10 ms radio frame or a newly defined DRS transmission period, when a corresponding cell is in on state within a corresponding DRS transmission period, the PSS and the symbol between the SSS and the corresponding PSS and SSS In the gap and off state, the timing gap between the PSS and the SSS and the corresponding timing gap between the PSS and SSS can be defined differently. For example, in the case of configuring a new DRS, when the PSS and the SSS are defined to be transmitted twice in one radio frame, that is, in a 5 ms cycle, the FDD cell is in the ON state in the first slot and the 11th slot The PSS is transmitted through the last OFDM symbol of the first slot and the SSS is transmitted through the second OFDM symbol (i.e., the OFDM symbol immediately before the PSS) at the end of the same slot. In the off state, Symbol, it is defined that if the timing gap of the OFDM symbol between the PSS and the SSS is 0 according to the timing gap between the PSS and the SSS, the UE determines that the corresponding cell is in the on state and the gap is 2 in the off state .

Alternatively, the state of the corresponding cell can be classified based on the frequency of transmission of the PSS and the SSS within the corresponding DRS transmission period, that is, the density of the PSS / SSS. For example, if the transmission period of the DRS is set to 40 ms, the PSS / SSS is transmitted in 5 ms intervals in the same manner as the existing system in the on state, and PSS / SSS is transmitted in 20 ms intervals in the off state. It can be defined to indicate the state of the corresponding cell based on the reception frequency of the PSS / SSS within the DRS transmission period.

However, the timing gap and the DRS transmission period between the PSS and the SSS transmission symbol according to the state of the corresponding cell and the PSS / SSS according to the state of the corresponding cell, and the PSS / SSS density within the corresponding DRS transmission period are only examples, The timing gap between the PSS and the SSS transmission symbol and the corresponding PSS and SSS are defined differently based on the on state and the off state without limiting the specific value to the above value, And all cases where a state of a corresponding cell is indicated based on the density of the PSS / SSS in a DRS transmission period can be included in the present invention.

2. CRS-based indication method

When a conventional CRS is used in addition to PSS / SSS for a new DRS configuration, the CRS configuration in the on state and the off state may be taken separately to indicate the cell state to the UE. That is, the CRS transmission resources in the on state and the off state are separately set, so that the terminal can distinguish the state of the corresponding cell. As a method for this, it is possible to circularly shift the positions of CRS transmission resource elements (REs) transmitted through one subframe in on state and off state, respectively, in the OFDM symbol domain. In this case, after the UE synchronizes with the PSS / SSS, it detects the states of the corresponding cells through detection of two types of CRSs that are mutually shifted versions.

As another method, similarly to the above-mentioned PSS / SSS, it is possible to set the density of the corresponding CRS within one subframe or DRS transmission period to distinguish the states of the corresponding cells based on the density.

In addition, the CRS configuration information configuring the DRS in the on state and the off state described above can be transmitted to the UE through higher layer signaling in any cell or base station.

However, as described above, as a method of determining a CRS transmission resource location, an RRM measurement is performed based on a transmission resource position of a CRS expected in an on-state in each of the UEs, and a CRS transmission resource RRM measurement is performed based on the location, and the CRS transmission resource location can be determined by comparing the result of the RRM measurement. For example, it is possible to determine that the CRS is transmitted in a position where a better result is obtained from the two result values, and to determine the state of the cell based on the CRS.

3. CSI-RS configuration based indication method

When an existing CSI-RS is used for a new DRS configuration, different CSI-RSs may be defined to transmit different CSI-RSs depending on the state of the corresponding cell. That is, the CSI-RS configuration for DRS in the on state and the CSI-RS configuration for configuring the DRS in the off state are defined differently, and the UE can determine the status of the corresponding cell based on the CSI-RS configuration. For example, in an on state and an off state, an antenna port of a CSI-RS constituting a DRS may be set differently, or a CSI-RS resource configuration or a CSI-RS subframe periodicity may be set differently.

For example, when an existing CSI-RS is reused for a new DRS configuration, CSI-RS setting information according to the state of the corresponding cell is independently set in the DRS configuration information included in the measurement configuration information of the corresponding cell, Or to transmit different fixed configuration-based CSI-RSs to the DRS depending on the state of the cell.

For example, when a base station is defined to transmit CSI-RS configuration information for DRS through a measurement configuration message, CSI-RS configuration information for DRS and CSI-RS configuration information for DRS in the off state are set To be transmitted. According to the existing CSI-RS configuration method, when the CSI-RS is configured for an arbitrary terminal, the number of antenna ports, CSI-RS resource configuration information, and CSI-RS subframe configuration information are transmitted through RRC signaling. RS ports 15, CSI-RS ports 15 and 16, and CSI-RS ports 15 and 16, respectively, according to the number of CSI-RS antenna ports (1,2,4 or 8) 17,18}, and CSI-RS port {15,16,17,18,19,20,21,22}. The RRC messages of the rel-10 and rel-11 systems defined for the CSI-RS configuration are as follows. Rel-11 is further defined to additionally set scramblingIdentity value and QCL-related information for CSI-RS sequence generation.

Accordingly, when setting up the CSI-RS for DRS in an arbitrary cell, the antenna configuration setting information, the resource configuration information, and the subframeconfig information are set to the ON state setting information and the OFF state setting information, respectively, You can give it.

RS is defined to transmit CSI-RS based on a fixed antenna port and resource / subframe setting when the CSI-RS is used as DRS, And the corresponding antenna port and resource / subframe setting values in the off state may be defined as different values.

Although the present invention has been described based on the above-mentioned small cell deployment scenario, it is obvious that it can be commonly applied to all cell deployment scenarios regardless of cell size or type.

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

Referring to FIG. 8, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The controller 1010 implicitly controls the overall operation of the BS according to the indication of the status of the corresponding small cell to the UE based on the above-described necessity for performing the present invention.

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.

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

9, a user terminal 1100 according to another embodiment of the present invention 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 the recognition of the status of the small cell based on the DRS received from the base station by the terminal necessary for performing the above-described present invention.

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.

1. 3GPP TR 36.872

2. 3GPP TS 36.211

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 estimating a small cell on / off state of a terminal,
Receiving a discovery signal (DRS) from a base station; And
Estimating the small cell on-off state based on PSS, SSS, CRS and CSI-RS of the discovery signal.

Images