WO2016122113A1 - Method and device for discontinuous reception operation in wireless communication system - Google Patents

Abstract

Provided are a method and a device for discontinuous reception (DRX) operation in a wireless communication system supporting licensed assisted access (LAA). The method for DRX operation of a terminal in a wireless communication system supporting carrier aggregation between a serving cell in a licensed band and a serving cell in an unlicensed band may comprise the steps of: configuring at least one secondary serving cell on the unlicensed band on the basis of configuration information on the serving cell in the unlicensed band; receiving, from a base station, a channel acquisition indicator on the at least one secondary serving cell; and performing DRX operation on the at least one secondary serving cell on the basis of the channel acquisition indicator.

Description

Method and apparatus for discontinuous reception in wireless communication system

The present invention relates to a method and apparatus for each terminal to apply a discontinuous reception (DRX) operation to an unlicensed band in a wireless communication system.

Cellular is a concept proposed to overcome the limitations of service area, frequency, and subscriber capacity, and it is possible to reuse frequency spatially by dividing mobile service area into several small cells. . However, in a particular area such as a hotspot inside a cell, there is a great demand for communication, and in a particular area such as a cell edge or a coverage hole, reception sensitivity of radio waves may be reduced. In order to enable communication at hot spots, cell boundaries, and coverage holes, small cells, such as pico cells and femto cells, are included in a macro cell. A micro cell, a remote radio head (RRH), a relay, a repeater, and the like are installed together. Such a network is called a heterogeneous network. In a heterogeneous network environment, a macro cell is a large coverage cell, and a small cell such as a femto cell and a pico cell is a small coverage cell.

However, as the wireless communication traffic surges, even though such small cells are actively utilized, securing more frequencies is still an urgent problem. Accordingly, based on carrier aggregation (CA), a method of performing wireless communication using not only a licensed band but also frequencies of an unlicensed band such as a WiFi band has been discussed. CA is a technique for efficiently using fragmented small bands so that a group of physically continuous or non-continuous bands in the frequency domain can be combined to have an effect of using a logically large band. It is to.

On the other hand, in general, the power consumption by the receiving circuit of the terminal is a level that can not be ignored, the continuous operation of the receiving circuit increases the power consumption of the terminal. Accordingly, the wireless communication system supports discontinuous reception (DRX) to reduce power consumption of the terminal. DRX refers to a function that allows the UE to stop monitoring the Packet Data Control CHannel (PDCCH) for a predetermined period (ie, sleep period or inactive time). Repeat the inactivity time. Here, the activation time means the time for monitoring the PDCCH, and the inactivity time means the time for stopping monitoring of the PDCCH.

However, since the unlicensed band allows competitive access, when a CA is configured between the serving cell of the licensed band and the serving cell of the unlicensed band, the existing DRX operation cannot be applied as it is. For example, when a channel of an unlicensed band is acquired during an inactive time, a UE may not receive a PDCCH from a base station due to a DRX operation even though a channel of an unlicensed band is obtained. In order to prevent this, even when the terminal monitors the PDCCH through the serving cell of the unlicensed band at all times during the DRX operation, a problem occurs that the power of the terminal is excessively consumed. Therefore, there is a need for a definition of a DRX operation to solve this problem.

An object of the present invention is to provide a method and apparatus for DRX operation for an unlicensed band in a wireless communication system.

Another object of the present invention is to provide a DRX operation method and apparatus for data reception in a wireless communication system configured with carrier aggregation using a serving cell of a licensed band and a serving cell of an unlicensed band.

According to an aspect of the present invention, in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band, a DRX operation method of a terminal is described above. Configuring at least one secondary serving cell on the unlicensed band based on configuration information regarding a serving cell of an unlicensed band, receiving a channel acquisition indicator for the at least one secondary serving cell from a base station; The method may include performing a DRX operation on the at least one secondary serving cell based on the channel acquisition indicator.

According to another aspect of the present invention, in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band, a terminal is configured to perform at least one on the unlicensed band based on configuration information of the serving cell of the unlicensed band. A configuration unit constituting a secondary serving cell of the at least one secondary serving cell, an RF unit for receiving a channel acquisition indicator from the base station and controlling the DRX operation for the at least one secondary serving cell based on the channel acquisition indicator It may include a control unit.

Even when carrier aggregation is configured between a serving cell of a licensed band and a serving cell of an unlicensed band, a DRX operation capable of efficiently receiving data transmitted by a base station is possible. Therefore, there is an advantage in correctly supporting the DRX operation for power consumption of the terminal. In addition, as data is received through the unlicensed band, the user has an advantage of reducing the cost of using the service.

1 shows a wireless communication system to which the present invention is applied.

2 shows examples of a LAA deployment scenario to which the present invention is applied.

3 is a diagram illustrating a DRX operation method according to an embodiment of the present invention.

4 is a diagram for explaining a DRX.

5 shows an example of timing for contention-based channel acquisition.

6 is a view showing a DRX operation method according to another embodiment of the present invention.

7 is a view showing a DRX operation method according to another embodiment of the present invention.

8 is a flowchart illustrating an operation of a terminal according to an embodiment of the present invention.

9 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.

10 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

In addition, the present specification describes a wireless communication network, the operation performed in the wireless communication network is performed in the process of controlling the network and transmitting data in the system (for example, the base station) that is in charge of the wireless communication network, or the corresponding wireless Work may be done at the terminal coupled to the network.

1 shows a wireless communication system to which the present invention is applied.

The network structure shown in FIG. 1 may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system may include a Long Term Evolution (LTE), an LTE-A (Advanced) system, and the like. Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

On the other hand, there is no limitation on the multiple access scheme applied to the wireless communication system. Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), OFDM-FDMA, OFDM-TDMA For example, various multiple access schemes such as OFDM-CDMA may be used.

Referring to FIG. 1, the E-UTRAN includes at least one base station (BS) 20 that provides a control plane and a user plane to the terminal. The UE 10 may be fixed or mobile and may have other mobile stations, advanced MSs (AMS), user terminals (UTs), subscriber stations (SSs), wireless devices (Wireless Devices), and the like. It may be called a term.

The base station 20 generally refers to a station communicating with the terminal 10, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and a femto-eNB. ), A pico base station (pico-eNB), a home base station (Home eNB), relay (relay) may be called other terms. The base station 20 may provide at least one cell to the terminal. The cell may mean a geographic area where the base station 20 provides a communication service or may mean a specific frequency band. The cell may mean a downlink frequency resource and an uplink frequency resource. Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource. Also, in general, when carrier aggregation (CA) is not considered, uplink and downlink frequency resources always exist in pairs in one cell.

An interface for transmitting user traffic or control traffic may be used between the base stations 20. The source base station (Source BS) 21 refers to a base station in which a radio bearer is currently set up with the terminal 10, and the target base station (Target BS, 22) means that the terminal 10 disconnects the radio bearer from the source base station 21 and renews it. It means a base station to be handed over to establish a radio bearer. The base stations 20 may be connected to each other through an X2 interface. The X2 interface is used to send and receive messages between the base stations 20. In addition, the base station 20 is connected to an evolved packet system (EPS), more specifically, a mobility management entity (MME) / serving gateway (S-GW) 30 through an S1 interface. The S1 interface supports a many-to-many-relation between base station 20 and MME / S-GW 30. The PDN-GW 40 is used to provide packet data services to the MME / S-GW 30.

Hereinafter, downlink means communication from the base station 20 to the terminal 10, and uplink means communication from the terminal 10 to the base station 20. The downlink is also called a forward link, and the uplink is also called a reverse link. In downlink, the transmitter may be part of the base station 20 and the receiver may be part of the terminal 10. In uplink, the transmitter may be part of the terminal 10 and the receiver may be part of the base station 20. In the wireless communication system, a time division duplex (TDD) scheme using different times may be used as an uplink transmission and a downlink transmission scheme, or a frequency division duplex (FDD) scheme using different frequencies may be used. Can be used.

Meanwhile, carrier aggregation (CA) supports a plurality of carriers and is also referred to as spectrum aggregation or bandwidth aggregation. Individual unit carriers bound by carrier aggregation are called component carriers (CC). Each component carrier is defined by a bandwidth and a center frequency. For example, if five component carriers are allocated as granularity in a carrier unit having a 20 MHz bandwidth, a bandwidth of up to 100 MHz may be supported.

Hereinafter, a multiple carrier system includes a system supporting carrier aggregation (CA). A serving cell may be defined as an element frequency band that may be aggregated by a CA based on a multiple component carrier system. The serving cell includes a primary serving cell (PCell) and a secondary serving cell (SCell). The primary serving cell is one that provides security input and non-access stratum (NAS) mobility information in a radio resource control (RRC) connection or re-establishment state. It means a serving cell. According to the capabilities of the terminal, at least one cell may be configured to form a set of serving cells together with the main serving cell, wherein the at least one cell is called a secondary serving cell. The set of serving cells configured for one terminal may consist of only one main serving cell or one main serving cell and at least one secondary serving cell. Each serving cell may be operated in an activated or deactivated state.

2 shows examples of a LAA deployment scenario to which the present invention is applied.

Simple cell division of macro and micro cells is difficult to meet the growing demand for data services. Therefore, small cells such as a pico cell, a femto cell, and a wireless relay may be used for data service. In general, since a small cell serves a smaller area than a macro cell, it is advantageous to a macro cell in terms of throughput that can be provided for a single terminal. However, as wireless communication traffic surges, more frequency is urgently needed to improve throughput. Accordingly, a method of performing wireless communication using not only a licensed band but also frequencies of an unlicensed band such as a WiFi band has been discussed. In order to smoothly support wireless communication in the unlicensed band, wireless communication in the unlicensed band may be provided with the support of the communication technique of the licensed band.

Hereinafter referred to as License Assisted Access (LAA) supports CA operation for one or more secondary serving cells operating in an unlicensed band or unlicensed spectrum based on the assistance of a primary serving cell operating in a licensed band or spectrum. A wireless communication scheme is shown. In other words, LAA is a technology that binds a licensed band and an unlicensed band to one using a CA as an anchor and a licensed band as an anchor. In this case, one of the serving cells in the licensed band is used as the main serving cell, and the serving cells in the unlicensed band may always be configured as secondary serving cells. In addition, the unlicensed band may be activated only through the CA and may not perform LTE communication alone. The UE accesses the network to the licensed band to use the service, and the base station may offload the traffic of the licensed band to the unlicensed band by combining the licensed band and the unlicensed band with a CA according to circumstances.

As an example, various LAA deployment scenarios are shown in FIG. 2. In each scenario, the number of licensed carriers and unlicensed carriers may be one or more, respectively. For example, scenario 1 is a case where a macro cell using a frequency carrier (F1), which is a license carrier, and a small cell using F3, which is an unlicensed carrier, are connected by carrier aggregation (CA). In this case, the macro cell and the small cell may be non-co-located and connected to each other by an ideal backhaul.

As another example, scenario 2 is a case in which small cell # 1 using a licensed carrier F2 outside of macro cell coverage and small cell # 2 using an unlicensed carrier F3 are connected by carrier aggregation. In this case, the small cell # 1 and the small cell # 2 may be co-located with each other, and thus an ideal backhaul may be assumed.

As another example, scenario 3 is a case where there is a macro cell using a licensed carrier F1 and a small cell # 1, and the small cell # 1 and the small cell # 2 using an unlicensed carrier F3 are connected by carrier aggregation. In this case, the macro cell and the small cell # 1 may be connected to each other by an ideal or non-ideal backhaul, and the small cell # 1 and the small cell # 2 may be connected to each other by an ideal backhaul (and co-located). Can be

As another example, scenario 4 includes a macro cell using a licensed carrier, F1, a small cell # 1 using a licensed carrier, F2, and a small cell # 2 using an unlicensed carrier, and a small cell # 1 and a small cell. # 2 is connected by carrier aggregation. In this case, the macro cell and the small cell # 1 may be connected to each other by an ideal or non-ideal backhaul, and the small cell # 1 and the small cell # 2 may be connected to each other by an ideal backhaul (and co-located). Can be If the macro cell and the small cell # 1 are ideally backhauled, the macro cell F1, the small cell # 1 (F2), and the small cell # 2 (F3) may be connected by carrier aggregation. .

However, since the unlicensed band allows competitive access, when a CA is configured between the serving cell of the licensed band and the serving cell of the unlicensed band, the existing discontinuous reception (DRX) operation cannot be applied as it is. For example, when the channel of the unlicensed band is acquired during the inactive time of the terminal, the terminal may not receive the PDCCH from the base station due to the DRX operation even though the channel of the unlicensed band is obtained. In order to prevent this, even when the terminal monitors the PDCCH through the serving cell of the unlicensed band at all times during the DRX operation, a problem occurs that the power of the terminal is excessively consumed. Therefore, when the terminal performs CA based on the LAA, an improved DRX operation method in the unlicensed band is required.

3, 6 and 7 are diagrams showing embodiments of DRX operation according to the present invention, FIG. 4 is a diagram for explaining specific parameters related to DRX operation of the present invention, and FIG. 5 is a diagram for contention-based channel acquisition. An example of timing is shown.

In the present specification, one main serving cell (PCell) and one first secondary serving cell (SCell # 1) are configured in a licensed band, and one secondary secondary serving cell (SCell # 2) is configured in an unlicensed band. It is assumed to be described. However, this is only an example, and the scenarios of the number and combination of primary serving cells and secondary serving cells in the licensed and unlicensed bands may vary, and the technical spirit of the present invention may be applied to all possible scenarios. Each of the secondary serving cells SCell # 1 and SCell # 2 may be operated in an activation or deactivation state, but in the present invention, the secondary serving cells SCell # 2 of the unlicensed band are currently activated. Assume

One system frame on the time axis may be composed of ten sub-frames as shown in FIG. 3. One subframe may consist of two slots.

Meanwhile, the wireless communication system supports discontinuous reception (DRX) in order to reduce power consumption of the terminal. DRX refers to a function that allows the UE to stop monitoring the PDCCH for a predetermined period (sleep period or inactive time). The UE repeats the active time and the inactive time in a constant cycle in the DRX mode as shown in FIG. 4, which is called a DRX operation. Here, the activation time refers to the time for monitoring PDCCH (Packet Data Control CHannel), and the inactivity time refers to the time to stop monitoring of the PDCCH. From the standpoint of the terminal, the terminal monitors the PDCCH during the active time and stops monitoring during the inactive time.

Referring back to FIG. 3, when the CA is configured based on the LAA, the DRX operation in the licensed band may be applied to the common DRX operation in which the in-band serving cells (PCell and SCell # 1) always have the same active time interval. have. In addition, in terms of DRX parameters, DRX parameters of a terminal unit may be configured. That is, DRX parameters commonly applied to the licensed band and the unlicensed band may be configured in the terminal. Alternatively, the first DRX parameters applied to the licensed band and the second DRX parameters applied to the serving cells of the unlicensed band may be configured independently. In this case, the first DRX parameters and the second DRX parameters may be the same as or different from each other.

First, the DRX operation in the licensed band will be described in more detail as follows.

For example, the DRX cycle may be set to 16 subframe sections, and the active time and inactive time may be set to 2 subframe sections and 14 subframe sections, respectively. The terminal transmits a power power control (TPC) -PUCCH- that can identify that a cell-Radio Network Temporary Identifier (C-RNTI), which is a unique identifier of the terminal, or uplink channel-specific power control information is included during the active time. Monitoring of the scrambled PDCCH may be performed based on the SPS-RNTI, which may identify that resource allocation information for RNTI, TPC-PUSCH-RNTI, and Semi Persistent Scheduling (SPS) is included. Monitoring of the PDCCH can be controlled by the DRX operation, the parameter related to the DRX is transmitted by the base station to the terminal by Radio Resource Control (RRC) signaling. In addition to the RNTIs, the UE monitors an operation related to a PDCCH scrambled with identifiers such as SI (System Information) -RNTI, P (Paging) -RNTI, and the like.

If the DRX parameter is configured in the RRC connected state, the terminal may perform discontinuous monitoring on the PDCCH based on the DRX operation. On the other hand, if the DRX parameter is not configured, the UE performs continuous monitoring on the PDCCH. Here, discontinuous monitoring means that the UE monitors the PDCCH only in a specific subframe (subframes # 0 and # 1 in FIG. 3), and continuous monitoring means that the UE monitors the PDCCH in all subframes. Can be.

The RRC layer manages several timers to control the DRX operation. The timer for controlling the DRX operation includes a duration timer (onDurationTimer), a DRX inactivity timer (drx-Inactivity Timer), a DRX retransmission timer (drx-Retransmission Timer). Other parameters to control DRX operation include long DRX cycle (longDRX-Cycle) and DRX start offset (drxStartOffset), and the base station optionally sets DRX short cycle timer (drxShortCycleTimer) and short DRX-cycle (shortDRX-Cycle). Can be. In addition, a HARQ round trip time (RTT) timer is defined for each downlink hybrid automatic repeat request (HARQ) process.

The DRX start offset is a value that defines the subframe where the DRX cycle begins. The DRX short cycle timer is a timer that defines the number of consecutive subframes that the UE should follow the short DRX cycle. The HARQ RTT timer is a timer that defines the minimum number of subframes before the interval in which downlink HARQ retransmission is expected by the UE.

The duration timer starts when the DRX cycle begins. In other words, the start of the duration timer coincides with the start of the DRX cycle. The duration timer expires when the value increases by '1' every PDCCH subframe and becomes equal to a preset expiration value. The duration timer is valid until the duration timer value is equal to the expiration value.

The DRX inactivity timer is a time for monitoring the PDCCH for successful decoding of the PDCCH to be received later from the time of successfully decoding the PDCCH for uplink or downlink user data transmission. The DRX Inactivity Timer is started or restarted when the UE successfully decodes the PDCCH for HARQ initial transmission in the PDCCH subframe.

The DRX retransmission timer is a timer that operates based on the maximum number of consecutive numbers of PDCCH subframes for which downlink retransmission is expected by the base station when decoding of HARQ process data previously received by the terminal fails. Since the DRX retransmission timer is basically for retransmission reception for the same HARQ process, the HARQ RTT timer that defines the time when retransmission does not occur for the same HARQ process should expire.

Therefore, although the HARQ RTT timer has expired, it is still started when the decoding of data in the corresponding HARQ process is not successful. The UE may define an active time while the DRX retransmission timer is in progress, and may monitor not only the reception of data retransmitted in the corresponding HARQ process but also other PDCCHs. The setting of the DRX retransmission timer is defined by the relevant parameter in the MAC-MainConfig message of the RRC layer. The DRX retransmission timer may be operated for each HARQ process.

If the DRX cycle is configured, the UE monitors the PDCCH for the PDCCH subframe during the active time. Here, the PDCCH subframe means a subframe including the PDCCH. The activation time may mean all sections in which the terminal is awake. For example, the terminal becomes an active time when at least one timer of the above-described duration timer, DRX inactivity timer, and DRX retransmission timer is in progress. In addition, even when a scheduling request is sent or pending through the PUCCH, it becomes an active time, and also when an uplink grant occurs for a pending HARQ transmission and data exists in a corresponding HARQ buffer. In addition, when a PDCCH indicating a new transmission to the C-RNTI of the UE is not received after the random access response for the preamble not selected by the UE is successfully received, the active time becomes the active time. A non-active time during the DRX cycle may be referred to as an inactive time. The activation time may be called a wake up period, and the inactivity time may be called a sleep period.

In addition, when the DRX is configured, the UE stops the duration timer and the DRX inactivity timer when a DRX command MAC control element is received in each subframe. In addition, when the DRX Inactivity Timer expires or a DRX Command MAC control element is received, use the short DRX cycle and start or restart the DRX short cycle timer, or use the long DRX cycle. The UE uses a long DRX cycle when the DRX short cycle timer expires. If the short term DRX cycle or the long term DRX cycle is used, the terminal starts the duration timer.

Meanwhile, the unlicensed band allows a base station or a terminal to acquire a channel access opportunity based on competition. There may be a variety of contention-based channel access methods, and the channel access mechanism for the unlicensed band according to the present invention includes the following.

The channel access mechanism according to the present invention provides opportunistic channel access. To this end, a wireless communication device such as a base station performs a clear channel assessment (CCA) or extended clear channel assessment (ECCA) before using a corresponding channel. This is to avoid concurrent transmissions on the same channel as other RLAN (Radio Local Area Network) systems. Here, the CCA or ECCA determines whether the channel is in the state of channel interference, occupancy or channel non-occupancy through the energy scan or detection of the channel, that is, whether the channel is busy or idle. This is the procedure. Such a channel access mechanism may be referred to as Listen Before Talk (LBT) or Carrier Sense (CS).

Under the LBT protocol, the wireless communication device determines whether the channel is available for transmission based on the energy measured in the channel. LBT may be performed frame-based or load-based. 5 illustrates timing for frame-based LBT as an example. Referring to FIG. 5, parameters such as CCA, Extended CCA, channel occupancy time, idle period, CCA energy detection threshold, etc. may be included in order to satisfy the LBT requirement. Can be defined. A wireless communication device using an unlicensed band may perform an (E) CCA check at the end of an idle period before starting transmission on an operating channel.

That is, the wireless communication device can determine the occupancy state of the channel by performing (E) CCA check for the (E) CCA execution time within the idle period. If the wireless communication device correctly receives the packet intended for the device on the channel occupied by the previous CCA, if it has not exceeded the maximum channel occupancy time, the wireless communication device does not perform (E) CCA again. (E.g., ACK and Block ACK frames) may be transmitted.

This competitive channel acquisition mechanism in the unlicensed band can affect DRX operation in the unlicensed band. Because the mobile communication system operating in the licensed band does not have a competitive channel acquisition operation, it is not necessary to inform the terminal that the base station has acquired the corresponding channel. However, in the unlicensed band, if the base station does not have signaling for notifying whether the channel is acquired, the terminal may not know whether the base station acquires the downlink channel, and thus power consumption may occur due to unnecessary data reception operation.

Accordingly, in order to prevent such unnecessary power consumption according to the present invention, the DRX operation in the unlicensed band is to provide various embodiments according to the manner in which the base station informs the terminal that the channel has been acquired. In addition, the base station may inform the terminal explicitly or implicitly that the channel has been acquired. For example, information indicating that a channel is acquired by the base station is called a channel acquisition indicator.

As an embodiment, the base station may indicate that the channel is acquired in the unlicensed band by transmitting a preamble or a reference signal (RS) as a channel acquisition indicator to the terminal. That is, the base station may implicitly inform the terminal of the acquisition of a channel through a preamble or a reference signal. In this case, when the UE receives the preamble or reference signal, it can recognize it as a channel acquisition indicator. In more detail, when the UE receives the preamble or the reference signal during the DRX inactivity time, the UE may recognize this as a channel acquisition indicator.

On the other hand, in relation to the transmission / reception timing aspect of the channel acquisition indicator, the channel acquisition indicator may include a corresponding sub-point from the end point of the (E) CCA period due to channel acquisition through the (E) CCA interval evaluation of the base station. It may be transmitted by the base station or received by the terminal within the frame end time interval. The time interval occupied by the channel acquisition indicator among the time intervals may be the entire period or a frame structure operating in a licensed band to prevent the occupancy by equipment in another wireless communication system using the same unlicensed band. Or may be part of the OFDM symbol interval. In addition, the frequency band occupied by the channel acquisition indicator in the available frequency band in the corresponding serving cell may be all for the same reason, and a part considering the frame structure or OFDM symbol interval operating in the license band for the whole May be

In one aspect, as shown in FIG. 3, the base station performs (E) CCA in the first slot of sub-frame # 1 in system frame # 1 to acquire a channel. In this case, the base station may transmit a channel acquisition indicator (preamble or RS, etc.) through the secondary serving cell (SCell # 2) of the unlicensed band in the second slot of the corresponding subframe # 1 (sub-frame # 1). When the terminal receives a preamble, RS, etc., which is promised as a channel acquisition indicator through a secondary serving cell (SCell # 2) of the unlicensed band, the terminal may recognize that the base station has acquired the corresponding channel. In this case, the (E) information data is not transmitted to the terminal in the end point section of the sub-frame (sub-frame # 1) from the end point of the CCA section. Therefore, the serving cells of all activated unlicensed bands before the UE recognizes the channel acquisition time of the base station may maintain inactivity time in all subframes after activation. That is, the UE may not always perform the monitoring operation for the (E) PDCCH scrambled with the RNTI associated with the DRX operation until the terminal recognizes the end time of the (E) CCA interval. However, the terminal monitors the channel acquisition indicator (preamble or RS, etc.) during the inactivity time. Here, the (E) PDCCH is a channel for transmitting control information to which a beamforming technique is applied similarly to PDSCH transmission based on DMRS. It is also used as a channel for delivering control information based on the MIMO technique. The PDCCH can be monitored based on the unique identifier of the UE, Cell-Radio Network Temporary Identifier (C-RNTI), Transmission Power Control (TPC) -PUCCH-RNTI, TPC-PUSCH-RNTI, and Semi Persistent Scheduling (SPS) -RNTI. Can be. Extended PDCCH (EPDCCH) may be monitored based on the number of resource elements available as EPDCCH, Downlink Control Information (DCI) format, and coding rate for common DCI.

The monitoring section is configured to monitor a part of the channel occupancy time based on a fixed frame period parameter determined internally by the base station as shown in FIG. 5 when the base station performs ECCA through frame-based LBT. One channel acquisition indicator monitoring parameters may be instructed to the UE through a licensed band using RRC signaling. The channel acquisition indicator monitoring parameters may be configured in the terminal separately from DRX. In the present invention, as an example, it is assumed that the DRX operation and the channel acquisition indicator monitoring operation cannot be operated at the same time.

In another aspect, DRX related timers for unlicensed band secondary serving cells (SCell # 2) operating in LAA form may be operated independently of DRX related timers for licensed serving cells (PCell and SCell # 1). have.

As an example, the terminal may change a value of an on duration timer for the secondary serving cell (SCell # 2) of the unlicensed band based on the channel acquisition interval information. Here, the channel acquisition interval information may be included in the preamble and transmitted from the base station to the terminal, may be transmitted independently, or may be transmitted in a signal other than the preamble.

As another example, the UE may perform the DRX operation based on information on when to apply the DRX operation to the secondary serving cell (SCell # 2) of the unlicensed band, that is, information on the back-off time. have. Here, the information about the back off time may be included in the preamble and transmitted from the base station to the terminal, may be transmitted independently, or may be transmitted in a signal other than the preamble.

For example, the terminal receives a preamble including information indicating two subframe intervals as a back off time in subframe # 1 of system frame # 1 through a secondary serving cell (SCell # 2) in an unlicensed band. As shown in FIG. 3, the DRX parameter may be applied to the sub-serving cell (SCell # 2) of the unlicensed band from subframe # 4 of the system frame # 1. Accordingly, the terminal may receive data from the subframe # 4 of the system frame # 1 through the secondary serving cell (SCell # 2) of the unlicensed band. Alternatively, the information about the back off time may be provided by the base station through RRC signaling as one of the channel acquisition indicator monitoring parameters.

As another example, the terminal may change the drxStartOffset value for the serving cells in the unlicensed band or change the short cycle and / or long cycle value to start the duration timer to transition to the active time based on the channel acquisition time. It may be. The drxStartOffset and the short / long cycle value determine a condition for starting the duration timer as shown in the following equation.

For short cycles: [(SFN * 10) + subframe number] modulo (shortDRX-Cycle) = (drxStartOffset) modulo (shortDRX-Cycle)

For long cycles: [(SFN * 10) + subframe number] modulo (longDRX-Cycle) = drxStartOffset

Here, SFN is a system frame number. DRX parameters for the secondary license cell of the unlicensed band are applied from a subframe (sub-frame # 1 in FIG. 3) including a time point at which a contention-based channel acquisition interval ends, or after a back-off time point (sub- in FIG. 3). frame # 4).

As another example, reception of a channel acquisition indicator may be added to a condition in which the UE starts a DRX inactivity timer to transition to an active time based on the channel acquisition time. DRX parameters for the secondary license cell of the unlicensed band are applied from a subframe (sub-frame # 1 in FIG. 3) including the time point at which the contention-based channel acquisition interval ends, or after the back-off time point (sub-frame in FIG. 3). # 4).

Meanwhile, as another embodiment, the base station may explicitly indicate that the channel is acquired in the unlicensed band by transmitting the EPDCCH including the channel acquisition indicator to the terminal through the secondary serving cell of the unlicensed band. In this case, the DRX operation may be performed as shown in FIG. 6, for example.

6 is a view showing a DRX operation method according to another embodiment of the present invention.

FIG. 6 illustrates a DRX operation method when a base station acquires a channel by performing an (E) CCA check in a first slot of subframe # 1 in system frame # 1. . In this case, the base station transmits a physical layer control message including a channel acquisition indicator from the first OFDM symbol of the second slot of the corresponding subframe # 1 through the SCell # 2 of the unlicensed band. Can transmit When the terminal receives the physical layer control message through the secondary cell (SCell # 2) of the unlicensed band, it can recognize that the corresponding channel in the unlicensed band is obtained. Here, the physical layer control message may be an extended PDCCH (EPDCCH). In order to receive the EPDCCH, the UE may maintain an active time in all subframes after activating all of the activated cells in the unlicensed band before the end of the (E) CCA interval. That is, the monitoring operation for the EPDCCH scrambled with the RNTI to be monitored through the DRX operation may be performed. In this case, the information data may be transmitted to the corresponding UE from the end of the (E) CCA interval or from the second slot of the corresponding subframe (sub-frame # 1).

In this case, the DRX-related timers for the unlicensed band secondary serving cell (SCell # 2) operating in the LAA form may be operated independently of the DRX-related timers for the serving cells (PCell and SCell # 1) in the licensed band. . For example, the physical layer control message may include channel acquisition interval information for an unlicensed band. In this case, the terminal may change the value of an on duration timer for the secondary cell (SCell # 2) of the unlicensed band based on the channel acquisition interval information included in the physical layer control message. In addition, the value of the DRX start offset short cycle and / or long cycle may be changed based on the channel acquisition interval information.

As another embodiment, the base station may explicitly indicate that the channel is acquired in the unlicensed band by transmitting the PDCCH or EPDCCH including the channel acquisition indicator to the terminal through the serving cell of the licensed band. In this case, the DRX operation may be performed as shown in FIG. 7, for example.

7 is a view showing a DRX operation method according to another embodiment of the present invention.

FIG. 7 illustrates a DRX operation method when the base station performs (E) CCA check in the first slot of subframe # 5 in system frame # 2 as another embodiment. In this case, the base station (E) the main serving cell (PCell) or secondary serving cell of the licensed band in the next subframe (sub-frame # 6) of the subframe (sub-frame # 5) including the end time of the CCA interval A physical layer control message including a channel acquisition indicator may be transmitted through (SCell # 1).

FIG. 7 illustrates an example in which a PDCCH is transmitted through a main serving cell as a physical layer control message. The physical layer control message may include a PDCCH and an EPDCCH. When the UE receives a physical layer control message including a channel acquisition indicator through a primary serving cell (PCell) or a secondary serving cell (SCell # 1) of the licensed band, the terminal may recognize that the corresponding channel in the unlicensed band has been acquired. Accordingly, the UE may maintain inactivity time in all subframes after activation for all activated serving cells of the unlicensed band before recognizing the channel acquisition time in the unlicensed band of the base station. That is, the monitoring operation for the (E) PDCCH scrambled with the RNTI associated with the DRX operation may not be performed until the end time of the (E) CCA interval is recognized. In other words, if the physical layer control message including the channel acquisition indicator for the unlicensed band is not received through the serving cell of the licensed band, the terminal may maintain the inactive time for the unlicensed band even though the active time for the licensed band. Accordingly, the activation time for the serving cells in the licensed band and the activation time for the serving cells in the unlicensed band defined by the DRX operation may be different.

However, since the UE recognizes the channel acquisition in the unlicensed band, DRX related timers for the unlicensed band (SCell # 2) in the LAA type and the serving cells in the licensed band (PCell and The activation time for SCell # 1) can be applied in common.

In this case, the UE can recognize that the base station has acquired the corresponding channel in the unlicensed band only after confirming the (E) PDCCH received through the subframe # 6, so that the UE can decode the (E) PDCCH and check the information. The viewpoint cannot be completed before the subframe # 6. Accordingly, the monitoring operation for (E) PDCCH transmitted by the base station through the corresponding channel in the unlicensed band is performed in the (E) CCA section ending time point (channel acquisition time point) from the end point of the corresponding subframe (sub-frame # 6). It can't be done. On the other hand, when the terminal fails to transmit data through the serving cell in the unlicensed band, the UE may start the DRX retransmission timer corresponding to the corresponding HARQ process to transition to the active time for retransmission reception. However, when the acquisition of the channel in the unlicensed band fails according to an embodiment of the present invention, the signal transmitted from the base station through the corresponding channel cannot be received and thus has a continuous inactivity time regardless of the active time in the licensed band. In this case, timers related to DRX operation do not operate based on the serving cells in the unlicensed band.

However, the UE operates the resources of the serving cell in the unlicensed band through cross-carrier scheduling, and when the first or the retransmission is received but the decoding of the data included in the PDSCH fails and the HARQ RTT timer expires, the channel in the unlicensed band If the acquisition fails and the base station is unable to retransmit through the corresponding serving cell, the retransmission data for the HARQ process in the serving cell can be transmitted through another serving cell through the serving cell operation in the physical layer. Here, the cross-carrier scheduling, the base station transmits the PDCCH1 through the DL SCC, PDSCH1 indicated by the PDCCH1 is a terminal via UC (Unlicensed carrier) of SDL (Supplement DownLink: configuration in which only DL subframe in TDD) In this case, the operation of transmitting the PDCCH and the PDSCH on different serving cells is referred to as cross-carrier scheduling. Information on a serving cell in which the PDSCH1 corresponding to the PDCCH1 is present in the PDCCH1 is included for the cross-carrier scheduling, and the base station is included in the serving cell configuration information subjected to cross-carrier scheduling through an RRC reconfiguration procedure to configure cross-carrier scheduling. The terminal includes the serving cell information for cross-carrier scheduling. Here, before using the SDL, the base station first checks whether it is possible to occupy through the CCA or the DCS, and assumes that the base station occupies the SDL UC.

Additionally, in the present invention, cross carrier HARQ operation will be described.

Cross-carrier HARQ operation, when the base station transmits PDCCH1 through the DL SCC, and transmits the PDSCH1 indicated by the PDCCH1 to the terminal through the UC of the SDL, the terminal attempts to decode after receiving the PDSCH1, if decoding fails A method of transmitting a HARQ NACK to the base station through the UL PCC. At this time, the base station should perform data retransmission upon receiving the HARQ NACK, and should check whether the UC of the SDL can be continuously used (that is, occupied) for data retransmission.

If the occupancy of the SDL UC is found to be sustainable, the base station continues to use the UC of the SDL (i.e., its serving cell where the current data transmission occurs) to perform retransmission of the PDSCH (i.e., transmission of PDSCH2) with PDSCH2. Transmits the PDCCH2 including a flag indicating that the serving cell is a UC of the SDL to the UE. Alternatively, when the UE can confirm that the SDL in the UC is occupied by the occupancy indicator transmitted from the base station, the UE may recognize that the serving cell to which the PDSCH2 is transmitted is the UC of the SDL without additional signaling. In this case, the UE recognizes that retransmission of the PDSCH by HARQ NACK is performed in the UC of the SDL, and receives the PDSCH2 in the UC of the SDL.

However, if it is determined that the occupancy of the SDL UC is impossible, that is, the terminal does not receive the occupancy indicator transmitted from the base station and thus does not receive the occupancy of the SDL UC of the base station, the base station is configured as a scheduling serving cell (DL). Retransmission of the PDSCH (ie, transmission of PDSCH2) through SCC), and together with this, a PDCCH2 including a flag indicating that the serving cell in which PDSCH2 is transmitted is a DL SCC is transmitted to the UE through the DL SCC. Alternatively, if the terminal cannot confirm that the occupancy indicator transmitted from the base station is occupied by the SDL in the UC, the terminal cannot determine retransmission serving cell information when the non-occupancy is included in the SDL UC configuration information from a predetermined rule or the base station. It can be recognized that retransmission (ie, transmission of PDSCH2) of PDSCH is performed through a secondary serving cell (DL SCC) configured as a scheduling serving cell. In this case, the UE recognizes that retransmission of the PDSCH by HARQ NACK is performed in the DL SCC, and receives the PDSCH2 in the DL SCC.

The 1-bit flag mentioned in the present invention indicates a serving cell indication for PDSCH retransmission. For example, when set to 0, the flag indicates a DL SCell (UC), and when set to 1, a scheduling serving cell. It may be applied to indicating # 0 (a scheduling serving cell set by the RRC for cross carrier scheduling).

In addition, when the cross-carrier HARQ is applied, the state of the serving cells in the licensed band to transition to the active time to receive the retransmission data of the data transmitted through the serving cell in the unlicensed band through the serving cell in the licensed band do. Therefore, the UE should maintain the operation of the HARQ RTT timer and the DRX retransmission timer even if it is determined that the channel including the serving cell in the unlicensed band is not obtained by the base station. However, the activation time due to the operation of the timers does not apply to the serving cells in the unlicensed band.

8 is a flowchart illustrating an operation of a terminal according to an embodiment of the present invention.

Referring to FIG. 8, in a wireless communication system supporting carrier aggregation (CA) between a serving cell of a licensed band and a serving cell of an unlicensed band, a terminal may perform the following DRX operation.

The UE may configure at least one secondary serving cell on the unlicensed band based on configuration information (hereinafter referred to as LAA configuration information) regarding the serving cell of the unlicensed band (S810). For example, the LAA configuration information may be transmitted from the base station to the terminal through the main serving cell of the licensed band, it may be transmitted through an RRC message. Here, the RRC message may be an RRC connection reconfiguration message. SCell configuration information of the unlicensed band may include frequency band and center carrier information to which an unlicensed carrier is assigned. Since this is derived through the EARFCN value, the EARFCN value may be included in the secondary serving cell configuration information to indicate which frequency band and which center carrier the corresponding serving cell corresponds to.

Subsequently, when the UE receives the channel acquisition indicator for at least one secondary serving cell configured on the unlicensed band from the base station (S820), the UE may recognize that the (C) CCA interval for the downlink has ended.

In operation S830, a DRX operation may be performed on at least one secondary serving cell configured on the unlicensed band based on the channel acquisition indicator.

Here, as an embodiment, the channel acquisition indicator may include a preamble or reference signal transmitted through at least one secondary serving cell on the unlicensed band from the end of the contention-based channel acquisition interval. The preamble or the reference signal may be transmitted to the terminal in a subframe including an end time point of the contention-based channel acquisition interval. In this case, the information data is not transmitted to the terminal until the end section of the subframe including the end point of the (E) CCA section.

Therefore, the terminal may maintain an inactivity time until receiving the channel acquisition indicator for the serving cells of the unlicensed band. That is, the UE may not perform monitoring of the (E) PDCCH through the serving cells of the unlicensed band. However, monitoring of the channel acquisition indicator may be performed. The preamble may include information on when to apply a DRX operation to at least one secondary serving cell configured on an unlicensed band, information on a channel acquisition interval, and the like. The terminal may change the value of the duration timer for the at least one secondary serving cell or change the value of the short term timer or the long term timer based on the information on the channel acquisition interval. Therefore, the DRX timer for the serving cell of the unlicensed band may operate independently of the DRX timer for the serving cell of the licensed band.

Meanwhile, as another embodiment, the channel acquisition indicator may be included in a physical layer control message transmitted through at least one secondary serving cell configured in the unlicensed band in a slot next to a slot including an end point of a contention-based channel acquisition interval. . The physical layer control message may be EPDDCH. When the UE receives the physical layer control message, it can recognize that the (E) CCA interval has ended and a corresponding channel has been acquired. In this case, the UE may perform a monitoring operation on the EPDCCH transmitted through the activated unlicensed band until the end of the (E) CCA interval is recognized. Accordingly, the information data may be transmitted to the UE from the (E) CCA period end time or from the second slot of the subframe including the (E) CCA period end time. In this case, the DRX-related timers for the unlicensed band serving cells operated in the LAA form may be operated independently from the DRX-related timers for the licensed serving cells. To this end, the physical layer control message may include channel acquisition interval information for the unlicensed band, information on the time to apply the DRX operation. In this case, the terminal may change the values of the duration timer, the short cycle timer and / or the long cycle timer for the serving cell of the unlicensed band based on the channel acquisition interval information included in the physical layer control message.

Meanwhile, as another embodiment, the channel acquisition indicator may be a physical layer transmitted through a serving cell (eg, a primary serving cell) of a licensed band in a next subframe including a end point of a contention-based channel acquisition interval. It may be included in a control message. The physical layer control message may be a PDCCH or an EPDCCH. In this case, since the physical layer control message is received through the serving cell of the licensed band, the serving cells of the unlicensed band may maintain an inactivity time after activation. That is, the monitoring operation of (E) PDCCH may not be performed on the serving cells of the unlicensed band. However, the DRX timer for the serving cells configured in the unlicensed band and the DRX timer for the serving cells configured in the licensed band may be commonly used.

9 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.

Referring to FIG. 9, in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band, a base station may perform the following operations for a DRX operation of a terminal.

The base station may transmit configuration information (LAA configuration information) about the serving cell of the unlicensed band to the terminal through the main serving cell of the licensed band. The LAA configuration information may be transmitted through an RRC message. Here, the RRC message may be an RRC connection reconfiguration message. The LAA configuration information may be information about a new secondary serving cell (unlicensed band of unlicensed band), and the information on the new secondary serving cell may be configured when a base station adds a serving cell of an unlicensed band to a serving cell set. Can be.

In addition, the base station may transmit a DRX parameter to the terminal through the RRC message (S910). The DRX parameter may be a parameter that is commonly applied without distinguishing between serving cells of a licensed band and serving cells of an unlicensed band. Alternatively, the RRC message may include another DRX parameter applied to the serving cells of the unlicensed band. The DRX parameter may include a duration timer (onDurationTimer), a DRX inactivity timer (drxInactivity Timer), a DRX retransmission timer (drxRetransmission Timer), a long DRX cycle (DRX Start Cycle), a DRX start offset (drxStartOffset), and the like.

Subsequently, the base station performs CCA check during (E) CCA period and acquires the channel of the unlicensed band. (E) Serving cell of unlicensed band operated in LAA form within the end point of the subframe including the end point of the (C) CCA period. Physical layer control including a channel acquisition indicator for a secondary serving cell configured in an unlicensed band from a first OFDM symbol of a slot immediately after the slot including the end of the CCA interval; E) transmits a message or transmits a physical layer control message including a physical layer including a channel acquisition indicator for a secondary serving cell configured in an unlicensed band through the next subframe including the end of the ECACCA interval to the UE. (E) CCA interval has ended and may inform that the channel of the unlicensed band is acquired (S920).

10 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 10, a wireless communication system supporting LAA according to the present invention includes at least one terminal 1000 and at least one base station 1100.

Each terminal 1000 includes an RF unit 1010, a processor 1120, and a memory 1030. The memory 1030 is connected to the processor 1020 and stores various information for driving the processor 1020. The RF unit 1010 is connected to the processor 1020 and transmits and / or receives a radio signal. For example, the RF unit 1010 may receive the LAA configuration information, the DRX parameter, the channel acquisition indicator, and the like posted from the present specification from the base station 1100.

The memory 1030 may store LAA configuration information, DRX parameters, channel acquisition indicators, and the like according to the present specification, and provide the information to the processor 1020 according to a request of the processor 1020.

The processor 1020 implements the functions, processes, and / or methods proposed herein. In detail, the processor 1020 allows all steps according to FIGS. 3, 6, and 7 to be performed. For example, the processor 1020 may include a component 1021, a recognizer 1022, a controller 1023, and a DRX processor (not shown).

The component 1021 configures at least one secondary serving cell on the unlicensed band based on configuration information (LAA configuration information) for the serving cell of the unlicensed band.

Recognizing unit 1022 recognizes that the channel acquisition indicator for at least one secondary serving cell configured based on the LAA configuration information is received from the base station based on the (E) CCA period is finished and the channel of the unlicensed band is obtained. .

The controller 1023 controls a DRX operation on at least one secondary serving cell configured in the unlicensed band based on the channel acquisition indicator.

The DRX processor checks the DRX parameters included by the RRC and performs a DRX operation. The DRX processor may control the DRX operation by independently managing and operating the DRX parameter of the licensed band serving cell and the DRX parameter of the distinguished unlicensed band serving cell. The DRX processor may determine whether to apply the common DRX parameter or the distinguished DRX parameter according to the secondary serving cell confirmed by the configuration unit 1021. This includes selectively applying DRX parameters according to the configured secondary serving cell information. In other words, the DRX processor applies different duration timers, DRX inactivity timers, DRX retransmission timers, long-term DRX cycles, DRX initiation offsets, and the like to the licensed serving cell and the unlicensed serving cell, respectively. The same duration timer, DRX inactivity timer, DRX retransmission timer, long-term DRX cycle, DRX start offset, etc. may be applied to the serving cell of the unlicensed band.

In one embodiment, the channel acquisition indicator may be transmitted from the base station 1100 through at least one secondary serving cell on the unlicensed band in a subframe including an end point of a contention-based channel acquisition interval. The channel acquisition indicator may include a preamble or a reference signal. In this case, the information data is not transmitted to the terminal 1000 until the end section of the subframe including the end point of the (E) CCA section. Accordingly, the controller 1023 may control the DRX processor to maintain an inactivity time until receiving the channel acquisition indicator for the unlicensed band serving cells. That is, the controller 1023 may control the terminal 1000 not to monitor the (E) PDCCH through the serving cells of the unlicensed band. However, monitoring of the channel acquisition indicator may be performed. Meanwhile, the preamble may include information on when to apply a DRX operation to at least one secondary serving cell configured on an unlicensed band, information on a channel acquisition interval, and the like. The controller 1023 may change the value of the duration timer for the at least one secondary serving cell based on the information on the channel acquisition interval, or change the value of the short term timer or the long term cycle timer of the terminal 1000. DRX operation can be controlled. That is, the DRX timer for the serving cell of the unlicensed band may operate independently of the DRX timer for the serving cell of the licensed band.

In another embodiment, the channel acquisition indicator may include a physical layer control message transmitted from the base station 1100 through at least one secondary serving cell configured in the unlicensed band in a slot next to a slot including an end point of a contention-based channel acquisition interval. May be included. The physical layer control message may be EPDDCH. When the physical layer control message is received by the RF unit 1010, the recognition unit 1022 may recognize that the (E) CCA period is finished and the corresponding channel is acquired. In this case, the controller 1023 may perform a monitoring operation on the EPDCCH transmitted through the activated unlicensed band until the end point of the (E) CCA period is recognized. Accordingly, the information data may be transmitted to the UE from the (E) CCA period end time or from the second slot of the subframe including the (E) CCA period end time. In this case, the DRX-related timers for the unlicensed band serving cells operated in the LAA form may be operated independently from the DRX-related timers for the licensed serving cells. To this end, the physical layer control message may include channel acquisition interval information for the unlicensed band, information on the time to apply the DRX operation. In this case, the controller 1023 may change the values of the sustain period timer, the short cycle timer and / or the long term cycle timer for the serving cell of the unlicensed band based on the channel acquisition interval information included in the physical layer control message.

In another embodiment, the channel acquisition indicator may be a physical layer control message transmitted through a serving cell (eg, a primary serving cell) of a licensed band in a next subframe including a termination time of a contention-based channel acquisition interval. It may also be included. The physical layer control message may be a PDCCH or an EPDCCH. In this case, since the physical layer control message is received through the serving cell of the licensed band, the serving cells of the unlicensed band may maintain an inactivity time after activation. That is, the monitoring operation of (E) PDCCH may not be performed on the serving cells of the unlicensed band. However, the DRX timer for the serving cells configured in the unlicensed band and the DRX timer for the serving cells configured in the licensed band may be commonly used.

Meanwhile, the base station 1100 includes a radio frequency (RF) unit 1110, a processor 1120, and a memory 1130. The memory 1130 is connected to the processor 1120 and stores various information for driving the processor 1120. The RF unit 1110 is connected to the processor 1120 to transmit and / or receive a radio signal. The processor 1120 implements the functions, processes, and / or methods proposed herein. In the above-described embodiment, the operation of the base station 1100 may be implemented by the processor 1120. The processor 1120 generates LAA configuration information and DRX parameters as disclosed herein, and performs a CCA check for an unlicensed band to obtain a channel.

To this end, the processor 1120 includes a LAA configuration information generator 1121, a DRX parameter generator 1122, and a channel acquirer 1123. The LAA configuration information and the DRX parameter generated by the LAA configuration information generator 1121 and the DRX parameter generator 1122 may be transmitted in the form of an RRC message to the terminal 1110 through the RF unit 1110. The RRC message may be an RRC connection reconfiguration message.

The DRX parameter generator 1122 may generate a DRX parameter for independently managing and operating the DRX parameter of the licensed band serving cell and the DRX parameter of the distinguished unlicensed band serving cell. The DRX parameter generator 1122 sets different duration intervals, DRX inactivity timers, DRX retransmission timers, long-term DRX cycles, DRX start offsets, and the like for the serving cell of the licensed band and the serving cell of the unlicensed band, respectively. The same duration timer, DRX inactivity timer, DRX retransmission timer, long term DRX cycle, DRX start offset, etc. may be set for the serving cell and the serving cell of the unlicensed band.

The channel acquirer 1123 performs a CCA check during the (E) CCA period to obtain a channel of an unlicensed band. When the channel of the unlicensed band is acquired, the RF unit 1110 may provide a preamble or a reference signal through a serving cell of the unlicensed band operated in the LAA form within the end of the subframe including the end of the (E) CCA interval. Transmit (E) a physical layer control message including a channel acquisition indicator for a secondary serving cell configured in an unlicensed band from the first OFDM symbol of a slot immediately after the slot including the end of the CCA interval, or (E) CCA A physical layer control message including a physical layer including a channel acquisition indicator for the secondary serving cell configured in the unlicensed band may be transmitted through a next subframe of the subframe including the interval end time. When the terminal 1000 receives the channel acquisition indicator described above, the terminal 1000 may recognize that the (C) CCA interval has ended and a channel of an unlicensed band has been acquired.

The above-described processor may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit and / or a data processing device. The memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device. The RF unit may include a baseband circuit for processing a radio signal. When the present embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in memory and executed by a processor. The memory may be internal or external to the processor and may be coupled to the processor by various well known means.

Claims (11)

A method of operating a Discontinuous Reception (DRX) of a UE in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band, Configuring at least one secondary serving cell on the unlicensed band based on configuration information about the serving cell of the unlicensed band; Receiving a channel acquisition indicator for the at least one secondary serving cell from a base station; And Performing a DRX operation on the at least one secondary serving cell based on the channel acquisition indicator DRX operation method comprising a. The method of claim 1, The channel acquisition indicator, And a preamble or a reference signal transmitted through the at least one secondary serving cell from an end point of a contention-based channel acquisition interval. The method of claim 2, The preamble or the reference signal, DRX operation method, characterized in that transmitted to the terminal in a subframe including the end time of the contention-based channel acquisition interval. The method of claim 2, The preamble, DRX operation method characterized in that it comprises information on when to apply the DRX operation to the at least one secondary serving cell. The method of claim 1, The step of performing the DRX operation, And changing a value of a DRX parameter for the at least one secondary serving cell based on the channel acquisition indicator. The method of claim 5, The DRX parameter is DRX operating method comprising a duration timer (on duration timer), a short cycle timer (short cycle timer) and a long cycle timer (long cycle timer). The method of claim 1, DRX timer for the at least one secondary serving cell, DRX operation method characterized in that it is operated independently from the DRX timer for the serving cell of the licensed band. The method of claim 1, The channel acquisition indicator, And a physical layer control message transmitted through the at least one secondary serving cell in a slot next to a slot including an end point of a contention-based channel acquisition interval. The method of claim 1, The channel acquisition indicator, DRX operation method, characterized in that included in the physical layer control message transmitted through the serving cell of the licensed band in the next subframe including the end time of the contention-based channel acquisition interval. The method of claim 9, DRX timer for the at least one secondary serving cell and DRX timer for the serving cell of the licensed band DRX operation method, characterized in that in common operation. A terminal in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band, A configuration unit configured to configure at least one secondary serving cell on the unlicensed band based on configuration information of the serving cell of the unlicensed band; A radio frequency (RF) unit for receiving a channel acquisition indicator for the at least one secondary serving cell from a base station; And Control unit for controlling the Discontinuous Reception (DRX) operation for the at least one secondary serving cell based on the channel acquisition indicator Terminal comprising a.

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