WO2016122110A1

WO2016122110A1 - Method and device for performing communication through unlicensed band in wireless communication system

Info

Publication number: WO2016122110A1
Application number: PCT/KR2015/013572
Authority: WO
Inventors: 박동현; 권기범
Original assignee: 주식회사 아이티엘
Priority date: 2015-01-28
Filing date: 2015-12-11
Publication date: 2016-08-04
Also published as: KR20160092680A

Abstract

The present invention relates to a method of performing license assisted access (LAA)-based communication in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band. The wireless communication system can perform data transmission through the unlicensed band, as well as perform data transmission/reception through the licensed band, thereby improving transmission efficiency.

Description

Method and apparatus for performing communication through unlicensed band in wireless communication system

The present invention relates to wireless communication, and more particularly, to a method and apparatus for performing communication on an unlicensed band in a wireless communication system.

As wireless communication traffic surges, small cells such as pico cells, femto cells, micro cells, remote radio heads (RRHs), Relays and repeaters are actively used, but securing more frequencies is an urgent problem. Accordingly, a method of performing wireless communication using not only a licensed band (L-band) but also frequencies of an unlicensed band (U-band) such as a WiFi band has been discussed.

However, since the unlicensed band allows competitive access, the access method in the existing licensed band cannot be applied as it is, and the radio frame structure in the unlicensed band may be different from the radio frame structure in the licensed band.

Accordingly, there is a need for a wireless communication technology in consideration of support / management / operation of a licensed band communication technique for smoothly supporting wireless communication in an unlicensed band.

The present invention relates to a method and apparatus for performing communication on an unlicensed band in a wireless communication system.

Another technical problem of the present invention is to provide an unlicensed band resource management method and apparatus in a wireless communication system.

Another technical problem of the present invention is to provide a method and apparatus for utilizing unlicensed band resources in support of licensed band communication.

Another technical problem of the present invention is to provide a method and apparatus for indicating the occupancy of the unlicensed band to the terminal.

Another technical problem of the present invention is to provide a method and apparatus for a terminal to monitor an unlicensed band.

According to an aspect of the present invention, a License Assisted Access (LAA) based communication method of a base station in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band To provide. The communication method includes performing an RRC connection reconfiguration procedure for configuring an unlicensed band carrier as an SCell for a terminal, transmitting an activation indicator for the configured SCell to the terminal, and obtaining a channel for the SCell. Performing channel, generating channel acquisition information indicating at least one of channel acquisition and acquired subframes for the SCell based on the channel acquisition procedure, and generating the generated channel acquisition information on the SCell. Characterized in that it comprises the step of transmitting to the terminal.

According to another aspect of the present invention, a License Assisted Access (LAA) based communication method of 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 To provide. The method includes performing an RRC connection reconfiguration procedure for configuring an unlicensed band carrier as an SCell, receiving an activation indicator for the configured SCell from the base station on a first subframe, based on the activation indicator Transitioning an SCell to an active state, and receiving channel acquisition information indicating at least one of channel acquisition and acquired subframes for the SCell from the base station.

According to another aspect of the present invention, performing license assisted access (LAA) based communication in a wireless communication system supporting carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band. It provides a terminal. The terminal includes a processor for performing an RRC connection reconfiguration procedure for configuring the carrier in the unlicensed band as an SCell, and an RF unit for receiving an activation indicator for the configured SCell from the base station on a first subframe. The SCell transitions to an active state based on the activation indicator, and the RF unit receives channel acquisition information indicating at least one of channel acquisition for the SCell and acquired subframes from the base station.

According to the present invention, in addition to performing data transmission and reception through a licensed band in a wireless communication system, data transmission can be performed through an unlicensed band, thereby improving transmission efficiency.

According to the present invention, carrier aggregation between a carrier in a licensed band and a carrier in an unlicensed band can be smoothly supported.

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 shows an example of timing for an FBE according to the present invention.

4 shows an example of a LAA based communication operation flow diagram according to the present invention.

FIG. 5 is a diagram exemplarily illustrating a case in which CA sets of different carriers are configured according to respective terminals.

6 is an example of a MAC CE structure including an activation / deactivation indicator.

7 is a diagram schematically illustrating a LAA operation according to a layer according to the present invention.

8 shows an example in which the UE performs preamble monitoring.

9 shows an example in which the UE performs CSI reporting according to the above-described other embodiment.

10 illustrates an example of a SCell deactivation timer related operation according to an embodiment described above.

11 is a flowchart illustrating an example of an LAA based communication operation performed by a LAA base station according to the present invention.

12 is a flowchart illustrating an example of an LAA based communication operation performed by a terminal according to the present invention.

13 is an example of a block diagram illustrating a LAA supporting base station and a terminal according to the present invention.

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings and examples, together with the contents of the present disclosure. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used 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 performed in a terminal included in the network.

The wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data. The wireless communication system 10 includes at least one base station 11 (evolved-NodeB, eNB). Each base station 11 provides a communication service for

specific cells

15a, 15b, and 15c. The cell can in turn be divided into a number of regions (called sectors).

The user equipment (UE) 12 may be fixed or mobile, and may include a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, and a PDA. (personal digital assistant), wireless modem (wireless modem), a handheld device (handheld device) may be called other terms. The base station 11 may be referred to by other terms such as a base station (BS), a base transceiver system (BTS), an access point, an femto base station, a home node B, a relay, and the like. A cell is meant to encompass all of the various coverage areas such as megacell, macrocell, microcell, picocell, femtocell, and the like.

Hereinafter, downlink (DL) means communication from the base station 11 to the terminal 12, and uplink (UL) means communication from the terminal 12 to the base station 11. In downlink, the transmitter may be part of the base station 11 and the receiver may be part of the terminal 12. In uplink, the transmitter may be part of the terminal 12 and the receiver may be part of the base station 11. 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. The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

Carrier aggregation (CA) supports a plurality of carriers, also referred to as spectrum aggregation or bandwidth aggregation. Individual unit carriers bound by carrier aggregation are called component carriers (CCs). The serving cell may be defined as an element frequency band that may be aggregated by carrier aggregation 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) establishment or reestablishment 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.

The downlink component carrier corresponding to the main serving cell is referred to as a downlink primary carrier (DL PCC), and the uplink component carrier corresponding to the main serving cell is referred to as an uplink major carrier (UL PCC). In the downlink, the component carrier corresponding to the secondary serving cell is called a downlink sub-component carrier (DL SCC), and in the uplink, the component carrier corresponding to the secondary serving cell is called an uplink sub-component carrier (UL SCC). do. Only one DL CC may correspond to one serving cell, and a DL CC and a UL CC may correspond together.

In general, since the small cell serves a smaller area than the macro cell, it is advantageous to the macro cell in terms of the throughput that can be provided for a single terminal. As the wireless communication traffic rapidly increases, the small cells as described above are actively used, but more frequency is urgently needed to improve performance.

In this regard, 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. To this end, the present invention proposes a method for performing wireless communication in an unlicensed band in consideration of support / management / operation of a licensed band communication technique for smoothly supporting wireless communication in an unlicensed band.

Hereinafter, in the present invention, LAA (License Assisted Access) refers to carrier aggregation for one or more SCells operating in an unlicensed band or unlicensed spectrum based on the control of a PCell operating in a licensed band or spectrum. A wireless communication technique that supports operation. In a LAA deployment scenario, an established SCell on the unlicensed band may be located within macro coverage, or may be located outside of macro coverage. In addition, the SCell set on the unlicensed band may be arranged in an indoor place such as a general home or a specific complex, or may be arranged in an outdoor place. In addition, the carriers of the licensed band and the unlicensed band may be co-location or non-co-located with each other. Here, the same location location may mean that a base station operating a carrier of a licensed band and a base station operating a carrier of an unlicensed band are the same base station or adjacent to RF (radio frequency) units.

If carriers in the licensed and unlicensed bands exist at non-uniform location locations, the first base station operating the carriers of the licensed band and the second base station operating the carriers of the unlicensed band are ideally backhauled to support smooth carrier aggregation. (ideal backhaul) can be connected. Here, the ideal backhaul may generally mean a backhaul having a delay of 2.5 s or less and a capacity of 10 Gbps or more, and the criteria for this may vary according to a communication environment and a wireless communication protocol.

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

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. .

Meanwhile, the terminal may establish dual connectivity through two or more base stations among the base stations configuring at least one serving cell. Dual connectivity is an operation in which the terminal consumes radio resources provided by at least two different network points (eg, macro base station and small base station) in a radio resource control connection (RRC_CONNECTED) mode. If dual connectivity is possible, dual connectivity between macro cell and small cell (s) may be configured in the above scenarios.

On the other hand, the regulations and standards to be followed in order to use the unlicensed band may be defined differently for each region and country. For example, the nominal channel bandwidth of the unlicensed carrier may be at least 5 MHz. And in the unlicensed band, the channel bandwidth occupies substantially 80% to 100% of the nominal channel bandwidth. Therefore, the unlicensed band used in the LAA system for the efficiency of the overall wireless communication system may support at least 10MHz or 20MHz bandwidth, may not support a bandwidth below 5MHz.

On the other hand, there may be a variety of contention-based channel access method for the unlicensed band, the channel access mechanism (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. In order to access the opportunity channel, a wireless channel device applies a clear channel assessment (CCA) before using the channel. This is to avoid concurrent transmission on the same channel as other RLAN (Radio Local Area Network) systems. Here, the CCA represents a procedure of determining whether the channel is in the state of channel interference or channel occupancy, that is, whether the channel is busy or idle through energy scan or detection of the channel. CCA may be performed based on whether energy was detected during a certain monitoring time. Here, it is possible to determine whether the corresponding channel is busy or idle by comparing an equivalent isotropic radio power (EIRP) obtained through energy detection with a predefined CCA threshold. The CCA check may be performed based on "energy detection" for a CCA monitoring time of 20 s or more. The channel access mechanism according to the present invention based on the carrier sense (CS), etc. may be referred to as List Before Talk (LBT).

ECCA may be used in LBT. The ECCA performs energy scans or detections by the duration of a factor N multiplied by a CCA observation time to determine whether the channel is in channel interference or channel occupancy. May be indicated. Herein, the factor N may be a random factor. The factor N may represent the number of clear idle slots. Intact idle slots consequently result in a full idle period, and the idle period needs to be monitored before starting transmission.

LBT can be divided into, for example, two kinds of behavior. One is Frame Based Equipment (FBE) and the other is Load Based Equipment (LBE).

The timing application in the FBE and LBE will be described in detail as follows.

3 shows an example of timing for an FBE according to the present invention.

Referring to FIG. 3, the CCA is performed in the FBE and resources that can be obtained through the FBE are defined as one frame structure. In an FBE, an idle period and a channel occupancy time are included in one frame period. The idle period here may be at least 5% of the channel occupation time. Also the children's period includes CCA (surveillance) time. Here, the CCA time may be, for example, 20 s or more. In FBE, CCA is performed once in one frame.

Unlike the FBE, a specific frame structure is not used in the LBE, and if there is a demand for data transmission (E), the (E) CCA check may be performed at any time. In performing the ECCA check, if the channel is not occupied for N CCA times, the corresponding transmitting node (or base station) may occupy the channel. The N value is randomly selected within a predetermined interval. The N value is randomly selected from "in the range of 1 to q value" and the q value has a "value between 4 and 32". Where q is a parameter used to determine N (the number of times the channel is idle after CCA).

On the other hand, in performing the TPC (Transmit Power Control) in the unlicensed band, many radio equipment using the unlicensed band must perform at least a certain level (for example, 3dB) power control. Through this, interference between wireless devices can be controlled in the unlicensed band.

In addition, when using an unlicensed band, dynamic frequency selection (DFS) operation may be considered. The purpose of DFS is to avoid interference with radar systems and to achieve near-uniform resource utilization in bands such as 5 GHz. DFS requirements can be represented as the following table as an example.

Table 1

Parameters	Requirement
DFS threshold	Region Specific
Channel availability check	> 60 sec
Channel move time	<10 sec
Non-occupancy time	> 30 min

Since the DFS requirement is based on long period values, the requirement can be met through higher layer signaling such as an SCell deactivation / deconfiguration message.

In addition, since many carriers in the unlicensed band can be used between various wireless communication systems, the transmitting node should be able to appropriately select one or some carriers in the unlicensed band in order to reduce fairness and interference between the wireless devices. . This may be called a carrier selection operation (in an unlicensed band).

In addition, the occupation of radio resources in the unlicensed band is discontinuous. For example, in Europe and Japan, the occupation of radio resources in the unlicensed band should be discontinuous. Discontinuous transmission is required for the LAA system according to the present invention to operate based on a global single framework. Support is required.

In a LAA system, many channels / carriers in an unlicensed band may be selected and used by a base station. For example, for the 5 GHz unlicensed band, as much as 450 MHz in Europe and 580 MHz in the United States may be used as an unlicensed band. Therefore, a large number of carriers can be configured in the unlicensed band and can be considered for a wireless communication scheme such as a CA. Carrier selection described above may also be utilized to maintain a channel usage distribution that is equivalent to efficient radio resource utilization with multiple nodes and other communication technology (eg, WiFi) nodes on this unlicensed band.

For example, a base station supporting a LAA system (hereinafter referred to as a LAA base station) may measure channels / carriers in an unlicensed band or request a terminal to measure and report channels / carriers in an unlicensed band. As a result, the serving cell (s) in the unlicensed band may be configured through RRC signaling as a serving cell (ie, SCell) capable of potential scheduling with a specific carrier or set of carriers. In some cases, of course, specific carrier (s) may be set to be occupied by fixedly transmitting nodes. For example, the number of nodes accessing a specific channel / carrier or performing data transmission based on long-term statistics, data load status (overload, medium load, or light load). Specific carrier (s) may be fixedly used in accordance with the operator's policy (e.g., a list of restricted channels / carriers accessible) or related regulations (LBT, DFS, TPC).

The present invention proposes a method for performing wireless communication in an unlicensed band in support of a licensed band communication technique to smoothly support wireless communication in an unlicensed band. In addition, the present invention proposes how to perform resource management of the unlicensed band, and how to perform wireless communication through the unlicensed band. In addition, the present invention proposes a procedure and a signaling method for selecting carriers in an unlicensed band and utilizing resources of the corresponding carriers.

Referring to FIG. 4, the LAA base station performs a carrier selection operation (S400). In this case, the carrier selection includes a carrier selection operation in the unlicensed band. The LAA base station can detect the occupancy frequency and the degree of interference of carriers (hereinafter, referred to as "u-carriers") on the unlicensed band. For example, the LAA base station measures information on the occupancy frequency and interference status of each u-carrier according to the LAA network and the WiFi network deployment environment, and measures channel measurement report of the corresponding LAA base station and / or terminals in the cell. You can figure it out. In this case, it is difficult to accurately identify the short-term channel environment, but the frequency of long-term channel utilization can be relatively accurately identified.

The LAA base station may select at least one unlicensed carrier in consideration of at least one of the following criteria. For example, the LAA base station may preferentially select idle carrier (s). In addition, the number of u-carriers to be selected may be determined according to traffic loading. For example, the LAA base station currently available at the LAA base station is semi-static in consideration of various conditions such as coordination among operators, regional regulatory requirements, and operator's deployment policy. The entire set of u-carriers may be determined.

The LAA base station performs an RRC connection reconfiguration procedure with the terminal (S410). The RRC connection reconfiguration procedure includes a step in which a LAA base station generates an RRC connection reconfiguration message and transmits it to a terminal, and the terminal transmits an RRC connection reconfiguration complete message to the LAA base station. The RRC connection reconfiguration message may be transmitted to the terminal through a PCell using a licensed carrier.

The RRC connection reconfiguration message may include secondary cell configuration information regarding the selected unlicensed carriers for the terminal. The RRC connection reconfiguration message may include a secondary serving cell configuration information field including content of configuring the selected unlicensed carriers by secondary serving cells. Configuration of a serving cell for carrier aggregation (CA) is performed UE-specifically.

For example, CA-specific configuration of the UE may be performed according to the capability of the UE (eg, how many CCs can be aggregated) and the number of the selected carriers to which an LAA base station can be allocated. In this case, the LAA base station may set the CA to different sets of carriers independently for each terminal. For reference, in this case, a PCell may be used for a licensed carrier and a licensed carrier and / or an unlicensed carrier may be used for an SCell.

Here, the CA configuration will be briefly described. As shown in FIG. 5, it is assumed that a set of different carriers is set according to each UE. FIG. 5 illustrates an example in which up to 16 carriers are configured by CA in a terminal, which is no more than 5 or 32 or less carriers in accordance with the performance of the terminal, the LAA base station, and the configuration between the terminals. It may be set.

UE1 of FIG. 5 is capable of supporting LAA and has a capability of performing CA operation on a larger number of carriers (eg, 16 CCs) than 5 CCs. On the other hand, UE2 / UE3 supports LAA, but CA can be performed by combining the carrier (s) of the licensed band and the carrier (s) of the unlicensed band within five CCs or less. For example, the carrier of the licensed band can be set to PCell or SCell, the carrier of the unlicensed band can be set to SCell.

Referring back to FIG. 4, the LAA base station may instruct the terminal of activation / deactivation of the CA configured SCell (S420, dotted line). The secondary serving cell activation / deactivation procedure receives an activation / deactivation indicator from the base station to activate / deactivate some or all of the secondary serving cells configured in the terminal by the LAA base station, and the terminal is based on the activation / deactivation indicator. Some or all of the configured secondary serving cells may be activated or deactivated. The activation / deactivation indicator may be received through the PCell of the licensed band.

According to an example of the present invention, the activation / deactivation signaling includes an activation / deactivation indicator in a media access control (MAC) layer for an unlicensed serving cell. The activation / deactivation indicator may be included in the MAC message and received by the terminal. The MAC message includes at least one MAC Control Element (MAC CE), and the at least one MAC CE includes an activation / deactivation indicator for the Scell of the unlicensed band.

Since the RRC configured serving cells are initially inactive except the PCell (ie, SCells), the MAC CE as shown in FIG. 6 may be used to indicate activation / deactivation of the SCells.

Referring to FIG. 6, the MAC CE may include n Ci fields and R fields. For example, the Ci field may include C7, C6, C5, C4, C3, C2, and C1 fields. The Ci field may indicate activation / deactivation of the corresponding secondary serving cell based on a value of 1 or 0, respectively. For example, when set to 1, the C1 field indicates activation of the secondary serving cell # 1, and when set to 0, indicates the deactivation of the secondary serving cell # 1. The R field is a reserved bit and may be set to zero. The PCell and the Physical Uplink Control Channel (PUCCH) SCell (SCell with PUCCH transmission set) may always be configured to be in an active state. In this case, the activation / deactivation indication is meaningless, so the field corresponding to the PCell and the PUCCH SCell is an R field. Can be set.

Meanwhile, according to another embodiment of the present invention, the activation / deactivation indication for the unlicensed serving cell may be performed without the separate MAC signaling. In this case, the base station may transmit an on / off indicator for the Scell through the PHY layer, to indicate the activation / deactivation for the Scell.

When the secondary serving cell is activated according to the present invention, the UE may perform physical downlink control channel (PDCCH) / extended PDCCH (EPDCCH) monitoring and decoding on the secondary serving cell, and transmit data and channel state information (CSI). Report and so on. On the other hand, when the secondary serving cell is deactivated, the UE does not perform PDCCH / EPDCCH monitoring and decoding on the secondary serving cell, and does not perform data transmission or CSI reporting.

Meanwhile, although the deactivated secondary serving cell may be used for a path-loss reference, the path loss reference of the deactivated secondary serving cell may be used less frequently than the activated secondary serving cell. In addition, when the secondary serving cell is deactivated, the DL CC of the secondary serving cell and the UL CC linked to the System Information Block (SIB) 2 are also deactivated, and the Physical Uplink Shared Channel (PUSCH) and the Sounding Reference (SRS) on the secondary serving cell are also deactivated. Uplink transmission of a signal is also prohibited.

Meanwhile, according to an example of the present invention, the LAA operation will be schematically described according to a layer. This is the same as FIG.

Referring to FIG. 7, C1 to C6 and C10 to C12 of a plurality of unlicensed component carriers are CA configured in a terminal by RRC layer signaling, and C1 to C3 and C11 among the CA carriers configured by MAC layer signaling. To C12 are activated, and the remaining C4, C5, C6 and C10 are inactive. When C1, C2 and C11 are occupied for the corresponding UE after LBT and C3 and C12 are not occupied by the PHY layer operation and signaling, the LAA base station and the UE perform LAA wireless communication operation based on CA on the unlicensed band. Can be done.

In this regard, the LAA base station performs a PHY signaling procedure to the terminal, the terminal checks the PHY signaling (S430). Here, the PHY signaling may include at least one of a preamble and (E) PDCCH transmission transmitted from the PCell.

1) Preamble Monitoring

If the terminal receives an activation indicator for SCell (unlicensed carrier based) in subframe n from the LAA base station, the terminal starts preamble monitoring from subframe n + m. Here, the preamble may include or indicate at least one of channel occupancy of the corresponding SCell, channel occupied location and interval, scheduling information, and cell ID of the corresponding SCell. M is an integer, and may be, for example, 4 or 8.

A process of performing preamble monitoring by the terminal according to an embodiment of the present invention will be described with reference to FIG. 8.

Referring to FIG. 8, SCell # 1 to SCell # 5 are configured in a terminal, and MAC signaling (activation / activation indicator included) indicating activation of SCell # 1 and SCell # 3 in subframe n from the LAA base station. ), The UE starts preamble monitoring from subframe n + m (here 8) of SCell # 1 and SCell # 3, and does not perform preamble monitoring on the remaining SCells that are not activated.

If the UE needs to perform preamble monitoring for all CCs configured only for RRC (ie, CA), this may cause too much processing complexity and power consumption for the UE. For example, if up to 32 CCs are configured, if the UE monitors all CCs unnecessarily, this may be too much burden on the UE. In addition, considering the purpose of activation / deactivation signaling introduced for the purpose of minimizing power consumption of the UE, it is not appropriate to perform monitoring for all RRC configured CCs.

Accordingly, in order to avoid the complexity and unnecessary power consumption, the UE monitors the reception of the preamble on the SCell from subframe n + m when the activation indicator for the specific SCell of the unlicensed band is received in the subframe n. That is, only on the SCell indicated by the activation indicator among the set SCells, the UE monitors preamble reception to obtain channel occupancy information due to LBT execution, RRM (Radio resource management), synchronization, CSI measurement and reporting, and AGC (automatic gain). control) and the like. Here, the AGC includes adjusting and providing the power received from the antenna to an appropriate power level that can be interpreted in the baseband chip according to the movement or channel environment of the terminal.

2) CSI Reporting

The UE may perform CSI reporting on the activated SCell. The LAA base station may adjust a modulation coding scheme (MCS) level and the like in performing scheduling to the LAA terminal based on the CSI report, and may provide scheduling suitable for a channel environment. The CSI report includes channel quality in the time and frequency domain, and information necessary for proper antenna processing in case of spatial multiplexing. The CSI report may include a Channel Quality Indicator (CQI), a Precoding Matrix Index (PMI), a Precoding Type Indicator (PTI), and a Rank Indication (RI).

In one embodiment, the UE starts after the subframe n + m starting the above-described preamble monitoring up to a subframe n + X at a later time, whether the UE periodically or not acquires the CSI report regardless of channel acquisition (or occupancy) based on the LBT of the base station. Can be performed aperiodically. If the terminal sometimes the wrong CSI (especially CQI) value is derived (that is, when the out-of-range value is derived) it reports to the LAA base station. The X value is defined by a timer or after the subframe n + m (preamble monitoring start subframe), at least by a value of a multiple of the maximum channel occupancy time or an arbitrary value through RRC signaling. Can be set. Its value can also be infinite. Therefore, once the UE starts monitoring the preamble, it may mean that the UE continues to monitor the preamble until the deactivation command is received.

In another embodiment, if the base station occupies (or obtains) a channel based on (E) CCA after the subframe n + m starting the above-described preamble monitoring, the information is transmitted to the terminal through the physical layer signaling such as the above-described preamble. If indicated, the terminal may perform CSI reporting on the activated SCell from subframe k in the occupied channel (occupied subframes). The CSI reporting may be performed through a serving cell (for example, a PUCCH transmitting serving cell) determined to perform CSI reporting. Here, the value of k is a value depending on occupying the channel through the (E) CCA operation, and includes an arbitrary value. 9 shows an example of performing CSI reporting according to an embodiment of the present invention.

Referring to FIG. 9, the UE receives an activation indicator for SCell # 1 and SCell # 3 or an indicator for cell selection (SCell on / off signaling) among a plurality of SCells configured in RRC, and receives subframe n + m ( In this case, preamble monitoring is started from 8), and after the base station performs (E) CCA, CSI reporting starts from subframe k in occupied subframes. Or (E) when the subframe occupied immediately by the CCA starts, CSI reporting can be started from the starting point k 'of the occupied subframes.

Meanwhile, the LAA base station may transmit SCell on / off signaling to the terminal. The SCell on / off signaling includes an SCell on / off status indicator indicating whether the SCell of the unlicensed band is on / off. The CSI report may be triggered when the UE receives the above-described preamble transmitted on the SCell or receives a physical channel (eg, PDCCH) including an on state indicator for the SCell.

On the other hand, when the SCell of the unlicensed band is activated, the SCell deactivation timer for the corresponding SCell is driven. When the SCell deactivation timer expires, the SCell transitions back to the deactivation state. The deactivation timer is a value set to the terminal by the base station and receives an activation indicator or an indicator for cell selection (SCell on / off signaling) in subframe n as described above. As soon as the indicated timer value expires, the terminal transitions the serving cell to the deactivated state without the deactivation indicator.

In an embodiment, when the terminal receives the activation indicator in subframe n, the SCell deactivation timer for the corresponding SCell starts from subframe n + m. M is an integer, and may be, for example, 4 or 8.

10 is a diagram illustrating an operation for an SCell deactivation timer according to an embodiment of the present invention.

Referring to FIG. 10, when the UE receives activation indicators for SCell # 1 and SCell # 3 of the unlicensed band in subframe n, the UE receives the corresponding SCell # 1 and SCell # 3 from subframe n + m (here 8). Each SCell deactivation timer for is started. When the timer for SCell # 1 expires, SCell # 1 transitions to an inactive state. Meanwhile, as in the case of SCell # 3, when the SCell deactivation timer succeeds in occupying the channel while driving, that is, when information such as a preamble indicating that the channel is acquired based on CCA from the LAA base station is received, the SCell deactivation timer for SCell # 3 Will restart.

Meanwhile, in another embodiment, after the subframe n + m, if the base station occupies a channel based on (E) CCA and the channel acquisition (or occupancy) information is known to the terminal through signaling such as preamble or PDCCH, acquisition The SCell deactivation timer for the corresponding SCell may be started from the start of the (or occupied) subframe.

If the SCell activation indicator is received by the terminal again or the channel occupancy information is received by the terminal before it expires after the SCell deactivation timer starts, the SCell deactivation timer is initialized (ie, restarted). In particular, when the SCell deactivation timer already started by the activator is running and the terminal receives the channel acquisition information by the base station, the SCell deactivation timer may be restarted, thereby preventing the SCell from being inadequately deactivated. have. This is useful when instructing the terminal of channel acquisition information of the base station through the preamble.

3) SRS (Sounding Reference Signal)

When uplink (UL) transmission is allowed in the SCell of the unlicensed band, the terminal may transmit the SRS on the corresponding SCell. For example, when the UE receives the activation indicator for the SCell or PHY signaling in subframe n, the channel is acquired based on (E) CCA after subframe n + m, and the channel acquisition information is signaled such as preamble or PDCCH. If known as a terminal through, the SRS is triggered and transmitted in at least one subframe set among occupied subframes. That is, in the terminal where the LAA is set, the SRS transmission timing is determined according to the state of channel occupancy of the base station or the terminal. Based on this, SRS transmission can be performed on the SCell of the unlicensed band.

Meanwhile, according to an embodiment of the present invention, the step S420 is omitted, and when the on / off mechanism of the SCell of the unlicensed band is dynamically applied by PHY signaling, the time of receiving the RRC signaling or the time of receiving the channel acquisition information, etc. The above-described embodiments can be performed based on the above.

In an LAA environment without activation / deactivation signaling, availability of a corresponding channel may be determined depending on PHY signaling. In this case, the following may be additionally considered in performing PHR.

4) Power Headroom Report (PHR)

The PHR is an operation in which the terminal reports surplus power of the current terminal to the base station, and the base station can schedule within the surplus power range. If a channel is acquired through (E) CCA operation, PHR may be triggered at this time. In this case, even if a channel is acquired on only one SCell, PHR for all configured SCell cells may be performed. In addition, if a serving cell group is used, PHR for all SCells in the serving cell group to which the channel is obtained may be triggered, or PHR for SCells in all serving cell groups may be triggered. The triggered PHR is calculated based on the difference between the calculated Pcmax, c value of each serving cell and the calculated uplink transmission power value, and the terminal reports this to the base station. Then, the LAA base station and the terminal are located on the SCell. Uplink / downlink communication may be performed on the occupied subframes (S440).

Referring to FIG. 11, the LAA base station performs an RRC connection reconfiguration procedure for configuring unlicensed carriers in an unlicensed band as SCells for a terminal (S1100). The RRC connection reconfiguration procedure includes a step in which a LAA base station generates an RRC connection reconfiguration message and transmits it to a terminal, and the terminal transmits an RRC connection reconfiguration complete message to the LAA base station. The RRC connection reconfiguration message may be transmitted to the terminal through a PCell using a licensed carrier. The RRC connection reconfiguration message may include secondary serving cell configuration information regarding the unlicensed carriers for the terminal. Those related to the present invention in the configuration information in the RRC connection reconfiguration message include information for preamble monitoring, information on a CSI measurement subframe, information on a deactivation timer setting value, and configuration information for uplink SRS / PHR reporting. can do.

The LAA base station transmits an activation / deactivation indicator for the SCells of the configured unlicensed band to the terminal (S1110). The activation / deactivation indicator may be transmitted through the PCell of the licensed band. The activation / deactivation indicator may be transmitted to the terminal through a MAC message. Indicate the status.

Alternatively, according to another embodiment of the present invention, the LAA base station may transmit a physical channel (for example, PDCCH) including a SCell on / off state indicator indicating whether the SCell of the unlicensed band is on / off state to the terminal. have.

The LAA base station performs a CCA based channel acquisition procedure on the SCells of the activated unlicensed band (S1120).

The LAA base station performs a PHY signaling procedure including a preamble (or PDCCH) transmission including channel acquisition information for at least one SCell of the unlicensed band based on the channel acquisition procedure (S1130). The channel acquisition information may indicate a channel-acquired SCell and subframes acquired for the corresponding SCell. The PHY signaling procedure includes at least one of receiving a CSI report for the SCell of the at least one unlicensed band, receiving an SRS for the SCell of the at least one unlicensed band, and receiving a PHR for the SCell of the at least one unlicensed band. It may further include.

If the activation indicator for the SCell of the unlicensed band is transmitted in subframe n, the LAA base station transmits the channel acquisition information on the SCell of the unlicensed band through the preamble (or PDCCH) from subframe n + m or later. Can be.

In addition, the LAA base station may receive a CSI report performed by the UE on the SCell of the unlicensed band starting at a time after the subframe n + m and at the latest within the subframe n + X. Alternatively, after transmitting the channel acquisition information, the LAA base station may receive a CSI report on the SCell of the unlicensed band from subframe k in the occupied subframes of the SCell.

In addition, the LAA base station may receive the SRS on at least one subframe of the occupied subframes of the SCell.

In addition, the LAA base station may receive a PHR for the SCell from the terminal when there is an SCell of the channel-licensed unlicensed band. The LAA base station may receive the PHR for the SCell of all configured unlicensed bands from the terminal.

By starting the preamble monitoring on the proposed timing, the base station receives channel occupancy and other information (CSI report triggering, automatic gain control (AGC), synchronization, etc.) to prepare for future data scheduling. Likewise, since the UE performs the CSI report to which the proposed method is applied, it is used for downlink scheduling after channel acquisition of the base station. In addition, SRS transmission and PHR related to uplink scheduling are performed from the terminal through the proposed method and transmitted to the base station, and the base station is used for future uplink scheduling through the received SRS and PHR.

The LAA base station performs data transmission / reception with the terminal on the occupied subframes on the at least one SCell of the unlicensed band indicated by the channel acquisition information (S1140).

Meanwhile, according to a configuration between the LAA base station and the terminal, the S1110 procedure may be omitted. In this case, in the S1120 procedure, the LAA base station performs a CCA-based channel acquisition procedure on all of the SCells configured for the terminal or a part of the selected SCells according to a predetermined criterion. Can be done.

Referring to FIG. 12, the UE performs an RRC connection reconfiguration procedure for configuring unlicensed carriers of an unlicensed band with SCells (S1200). The RRC connection reconfiguration procedure includes a terminal receiving an RRC connection reconfiguration message to a LAA base station, and the terminal transmitting an RRC connection reconfiguration complete message to the LAA base station. The RRC connection reconfiguration message may include secondary serving cell configuration information regarding the unlicensed carriers for the terminal. The secondary serving cell configuration information 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.

The terminal receives an activation / deactivation indicator for the SCells of the configured unlicensed band from the LAA base station (S1210). Meanwhile, according to another example of the present invention, the UE may receive a physical channel (eg, PDCCH) including an SCell on / off state indicator indicating whether the SCell of the unlicensed band is on / off.

The LAA base station performs a PHY signaling procedure including receiving a preamble (or PDCCH) including channel acquisition information for at least one SCell of the unlicensed band of the activated unlicensed band (S1220). The channel acquisition information may indicate a channel-acquired SCell and subframes acquired for the corresponding SCell. The PHY signaling procedure may perform one of CSI reporting for SCells in at least one unlicensed band, SRS transmission for SCells in at least one unlicensed band, and PHR reporting for SCells in at least one unlicensed band. .

More specifically, if the terminal receives the activation indicator for the SCell of the unlicensed band in subframe n, the terminal may perform preamble monitoring on the SCell of the unlicensed band from subframe n + m or later. Channel acquisition information may be received through the preamble (or PDCCH). Thereafter, the UE may perform CSI reporting on the SCell of the unlicensed band starting from after the subframe n + m and at the latest within the subframe n + X. Alternatively, after receiving the channel acquisition information, the LAA base station may perform CSI reporting on the SCell of the unlicensed band from subframe k in the occupied subframes of the SCell. In addition, the UE may transmit the SRS on at least one subframe among the occupied subframes of the SCell. In addition, when there is an SCell of the channel-licensed unlicensed band, the terminal may perform PHR for the SCell of the corresponding unlicensed band. Alternatively, PHR for SCells of all configured unlicensed bands may be performed.

The terminal performs data transmission and reception with an LAA base station on the occupied subframes on the SCell of the at least one unlicensed band indicated by the channel acquisition information (S1230).

Meanwhile, the S1210 procedure may be omitted according to the configuration between the LAA base station and the terminal. In this case, in the S1220 procedure, the terminal may perform preamble monitoring on all of the configured SCells or a part of the selected SCells according to a predetermined criterion. One PHY signaling procedure may be performed.

Referring to FIG. 13, the base station 1300 includes a memory 1305, a processor 1310, and an RF unit 1320. The memory 1305 is connected to the processor 1310 and stores various information for driving the processor 1310. The RF unit 1320 is connected to the processor 1310 and transmits and / or receives a radio signal. The processor 1310 implements a proposed function, process, and / or method for performing operations in accordance with the present invention. In the above-described embodiments, the operation of the base station may be implemented by the control of the processor 1310.

The processor 1310 includes a serving cell configuration unit 1311, an activation processing unit 1312, a CCA execution unit 1313, and a PHY processing unit 1314.

The serving cell configuration unit 1311 performs unlicensed carrier selection. The serving cell configuration unit 1311 may detect the occupancy frequency and the degree of interference of the unlicensed carriers on the unlicensed band, and select unlicensed carriers to be used for LAA operation with the terminal in the unlicensed band.

In addition, the serving cell configuration unit 1311 may generate an RRC connection reconfiguration message including information for configuring the selected unlicensed carriers as SCells for the terminal and transmit the generated RRC connection reconfiguration message to the terminal through the RF unit 1320. The SCell configuration information 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. The RRC connection reconfiguration message may be transmitted through a PCell using a license carrier. The RF unit 1320 may receive an RRC connection reconfiguration complete message from the terminal 1350.

The activation processor 1312 may generate an activation / deactivation indicator for the SCells in the unlicensed band configured in the terminal 1350 and transmit the activation / deactivation indicator to the terminal through the RF unit 1320. The activation / deactivation indicator may be included in a MAC message and transmitted to the terminal through the PCell.

The CCA execution unit 1313 performs a channel acquisition procedure for the SCells of the activated unlicensed band. The sound channel acquisition procedure may be performed based on CCA. The CCA performer 1313 may generate channel acquisition information for at least one SCell of the unlicensed band based on the channel acquisition procedure. The channel acquisition information may indicate a channel-acquired SCell and subframes acquired (occupied) for the corresponding SCell.

The PHY processor 1314 may generate a preamble (or PDCCH) including the channel acquisition information and transmit the preamble (or PDCCH) to the terminal through the RF unit 1320. The PHY processor 1314 may control to perform CSI reporting, SRS reception, and PHR reception for the SCell of the channel-licensed unlicensed band. The PHY processor 1314 may process and interpret the CSI report, SRS, and PHR. If the PHY processor 1314 transmits the activation indicator for the SCell of the unlicensed band in subframe n, the RF unit 1320 transmits the channel acquisition information to the preamble (or PDCCH) from subframe n + m or later. It can be controlled to transmit on the SCell of the unlicensed band through. In addition, the PHY processor 1314 may control the terminal 1350 to receive the CSI report performed by the UE 1350 on the SCell of the unlicensed band at the latest after the subframe n + m and at the latest within the subframe n + X. Alternatively, after transmitting the channel acquisition information, the RF unit 1320 may control to receive a CSI report on the SCell of the unlicensed band from subframe k in the occupied subframes of the SCell. In addition, the PHY processor 1314 may control to receive the SRS on at least one subframe of the acquired (occupied) subframes of the SCell. In addition, the PHY processing unit 1314 may control to receive the PHR for the SCell from the terminal 1350 when there is an SCell of the channel-licensed unlicensed band. The RF unit 1320 may control to receive the PHR for the SCell of all configured unlicensed bands from the terminal 1350.

Accordingly, the processor 1310 processes the PHY signaling in consideration of the operation of the PHY processing unit 1314, and then on the acquired (occupied) subframes of the SCell of the unlicensed band through the RF unit 1320. Scheduling is performed to perform data transmission / reception with the terminal 1350.

The terminal 1350 includes a memory 1355, a processor 1360, and an RF unit 1370. The memory 1355 is connected to the processor 1360 and stores various information for driving the processor 1360. The RF unit 1370 is connected to the processor 1360 and transmits and / or receives a radio signal. Processor 1360 implements the proposed functions, processes, and / or methods for performing operations in accordance with the present invention. In the above-described embodiment, the operation of the terminal may be implemented by the control of the processor 1360.

The RF unit 1370 receives the RRC connection reconfiguration message, the activation / deactivation indicator, and the channel acquisition information from the base station 1300.

The processor 1360 includes a serving cell component 1361, an activation processor 1362, and a PHY processor 1363.

The serving cell configuration unit 1361 configures SCells in the unlicensed band based on the RRC connection reconfiguration message. Thereafter, the serving cell configuration unit 1361 generates an RRC connection reconfiguration complete message and transmits the RRC connection reconfiguration complete message to the base station 1300 through the RF unit 1370.

The activation processing unit 1362 transitions the SCells of the configured unlicensed band to an activated or deactivated state based on the received activation / deactivation indicator.

The PHY processor 1363 may identify the channel-acquired SCell and the subframes acquired (occupied) for the corresponding SCell based on the channel acquisition information.

In addition, when receiving the activation indicator for the SCell of the unlicensed band in subframe n, the PHY processor 1363 may perform preamble monitoring on the SCell of the unlicensed band from subframe n + m or later, and the channel The acquisition information may be controlled to be received through the preamble (or PDCCH).

In addition, the PHY processing unit 1363 may perform CSI reporting on the SCell of the unlicensed band starting from after the subframe n + m through the RF unit 1370 and at the latest within the subframe n + X. Alternatively, after the RF unit 1370 receives the channel acquisition information, the PHY processing unit 1363 receives the CSI for the SCell of the unlicensed band from the subframe k in the occupied subframes of the SCell through the RF unit 1370. Report can be performed.

In addition, the PHY processor 1363 may transmit an SRS on at least one subframe of the occupied subframes of the SCell through the RF unit 1370.

In addition, the PHY processing unit 1363 may perform the PHR for the SCell of the unlicensed band or the PHR for the SCell of all configured unlicensed bands through the RF unit 1370 when there is a SCell of the channel-licensed unlicensed band.

In addition, the PHY processing unit 1363 may perform data transmission / reception with the base station 1300 on the acquired (occupied) subframes of the SCell of the unlicensed band through the RF unit 1370.

In the present invention, the processor may include an application-specific integrated circuit (ASIC), another chipset, logic circuit and / or 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 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

In the method for performing communication through the unlicensed band of the terminal in a wireless communication system,

Connecting a first serving cell of a licensed band to a radio resource control (RRC);

Receiving an RRC connection establishment message including information on a second serving cell of an unlicensed band through the first serving cell; The information on the second serving cell of the unlicensed band includes cell information of the unlicensed band for supporting carrier aggregation with the first serving cell.

Receiving a message including an activation / deactivation indicator for the second serving cell through the first serving cell;

Performing a channel acquisition procedure on the second serving cell; The channel acquisition procedure is for checking channel interference or channel occupation state of the second serving cell for a predetermined time;

In consideration of the channel acquisition procedure, preamble monitoring is performed through the second serving cell, channel state information (CSI) reporting, sounding reference signal (SRS) reporting, or power headroom (PHR). Performing at least one of the reporting.
The method of claim 1,

The activation / deactivation indicator is transmitted on a first subframe, the channel acquisition information is transmitted after a second subframe or the second subframe, and the second subframe is an eighth subframe after the first subframe. The communication method characterized by the above-mentioned.
The method of claim 2,

Receiving a channel state information (CSI) report for the second serving cell from the terminal on a third subframe;

And wherein the third subframe is located after the second subframe in the time domain.
The method of claim 2,

And the third subframe is one of the obtained subframes.
The method of claim 2,

And receiving a Sounding Reference Signal (SRS) from the terminal on at least one subframe of the obtained subframes of the second serving cell.
In a communication assisted access (LAA) based communication method of a terminal in a wireless communication system supporting carrier aggregation between a first serving cell of a licensed band and a second serving cell of an unlicensed band,

Performing an RRC connection reconfiguration procedure for configuring the carrier in the unlicensed band as an SCell;

Receiving an activation indicator for the configured SCell from the base station on a first subframe;

Transitioning the SCell to an active state based on the activation indicator; And

And receiving channel acquisition information indicating at least one of the acquired subframes and the channel for the SCell from the base station.
The method of claim 6,

Performing monitoring on channel acquisition information on the SCell from a second subframe;

And the second subframe is an eighth subframe after the first subframe.
The method of claim 7, wherein

The method may further include performing channel state information (CSI) report on the SCell from the terminal on a third subframe.

And wherein the third subframe is located after the second subframe in the time domain.
The method of claim 7, wherein

And the third subframe is one of the obtained subframes.
The method of claim 7, wherein

And receiving a Sounding Reference Signal (SRS) from the terminal on at least one subframe of the obtained subframes of the SCell.
A terminal for performing LAA (License Assisted Access) based communication 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 processor that performs an RRC connection reconfiguration procedure for configuring the unlicensed band carrier as an SCell; And

An RF unit for receiving the activation indicator for the configured SCell from the base station on a first subframe,

The processor transitions the SCell to an active state based on the activation indicator,

The RF unit, characterized in that for receiving the channel acquisition information indicating at least one of the channel acquisition and the obtained subframe for the SCell, the terminal.