WO2019216638A1 - Radio resource measurement method in unlicensed band and apparatus therefor - Google Patents

Abstract

Disclosed is a method for redirecting a serving cell by a terminal in an unlicensed band. In particular, the method may comprise: receiving information related to a radio resource measurement-reference signal (RRM-RS) transmission probability according to listen before talk (LBT) in each of multiple cells; acquiring whether to redirect a serving cell, on the basis of the information; and redirecting the serving cell on the basis of whether to redirect the serving cell, which has been acquired.

Description

Radio resource measurement method in unlicensed band and apparatus for same

The present invention relates to a method for measuring a radio resource in an unlicensed band and an apparatus therefor, and more particularly, to a transmission delay of RRM-RS (Radio Resource Measurement-Reference Signal) generated by List before Talk (LBT) in an unlicensed band. The present invention relates to a method for performing an operation related to RRM by a terminal and an apparatus therefor.

As time goes by, more communication devices require more communication traffic, and a next generation 5G system, which is an improved wireless broadband communication than the existing LTE system, is required. Called NewRAT, these next-generation 5G systems are divided into communication scenarios such as Enhanced Mobile BroadBand (eMBB) / Ultra-reliability and low-latency communication (URLLC) / Massive Machine-Type Communications (mMTC).

Here, eMBB is a next generation mobile communication scenario having characteristics such as High Spectrum Efficiency, High User Experienced Data Rate, High Peak Data Rate, and URLLC is a next generation mobile communication scenario having characteristics such as Ultra Reliable, Ultra Low Latency, Ultra High Availability, etc. (Eg, V2X, Emergency Service, Remote Control), mMTC is a next generation mobile communication scenario with low cost, low energy, short packet, and mass connectivity. (e.g., IoT).

The present invention provides a method for measuring radio resources in an unlicensed band and an apparatus therefor.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to an embodiment of the present invention, in a method of redirection of a serving cell (serving) by a terminal in an unlicensed band, RRM-RS (Radio) by LBT (Listen before Talk) in each of a plurality of cells Resource Measurement-Reference Signal) Receives information related to a transmission probability, obtains whether a serving cell is redirection based on the information, and resets a serving cell based on the obtained reset. have.

In this case, the information is a transmission counter value for the number of times the RRM-RS has been successfully transmitted, and the RRM-RS transmission probability may be calculated based on the transmission counter value received for a predetermined time.

In addition, when the RRM-RS transmission probability is greater than or equal to a predetermined threshold, the serving cell may be reset.

In addition, when the RRM-RS transmission probability of any one cell among the plurality of cells is smaller than a predetermined RRM-RS transmission probability of the serving cell, the one cell may be reset to the serving cell.

In addition, the signal quality of the serving cell may be higher than the signal quality of any one cell.

In addition, the information may be a transmission success probability of the RRM-RS or a transmission failure probability of the RRM-RS in the downlink burst, which is a total downlink transmission opportunity by the LBT for a predetermined time.

The terminal may communicate with at least one of a terminal, a network, a base station, and an autonomous vehicle other than the terminal.

An apparatus for resetting a serving cell in an unlicensed band according to the present invention, comprising: a memory; And at least one processor coupled to the memory, wherein the at least one processor comprises: Radio Resource Measurement (RRM-RS) by List before Talk (LBT) in each of a plurality of cells; Reference Signal) Receives information related to a transmission probability, obtains whether or not to reset a serving cell based on the information, and resets a serving cell based on the obtained reset.

In this case, the information is a transmission counter value for the number of times the RRM-RS has been successfully transmitted, and the RRM-RS transmission probability may be calculated based on the transmission counter value received for a predetermined time.

In addition, when the RRM-RS transmission probability is greater than or equal to a predetermined threshold, the serving cell may be reset.

In addition, when the RRM-RS transmission probability of any one cell among the plurality of cells is smaller than a predetermined RRM-RS transmission probability of the serving cell, the one cell may be reset to the serving cell.

In addition, the signal quality of the serving cell may be higher than the signal quality of any one cell.

In addition, the information may be a transmission success probability of the RRM-RS or a transmission failure probability of the RRM-RS in the downlink burst, which is a total downlink transmission opportunity by the LBT for a predetermined time.

The apparatus may be capable of communicating with at least one of a terminal, a network, a base station, and an autonomous vehicle other than the apparatus.

A terminal for resetting a serving cell in an unlicensed band according to the present invention, the terminal comprising: a transceiver; And at least one processor coupled to the transceiver, wherein the at least one processor comprises: Radio Resource Measurement (RRM-RS) by List before Talk (LBT) in each of a plurality of cells; Reference Signal) Controls the transceiver to receive information related to transmission probability, obtains whether or not to reset the serving cell based on the information, and resets the serving cell based on the obtained reset can do.

According to the present invention, more accurate RRM information can be obtained by correcting an RRM-RS measurement value based on information related to transmission delay of RRM-RS (Radio Resource Measurement-Reference Signal) by LBT (Listen before Talk). Can be.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

FIG. 1 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard.

2 is a diagram for explaining a physical channel used in the 3GPP system and a general signal transmission method using the same.

3 to 5 are diagrams for explaining the structure of a radio frame and slot used in the NR system.

FIG. 6 abstractly illustrates a hybrid beamforming structure in terms of a transceiver unit (TXRU) and a physical antenna.

7 shows a beam sweeping operation for a synchronization signal and system information during downlink transmission.

8 to 10 are diagrams for explaining uplink channel and downlink channel transmission in an unlicensed band.

11 to 14 illustrate a composition and a transmission method of an SS / PBCH block.

15 to 17 are diagrams for describing an operation process from a terminal, a base station, and a network perspective according to an exemplary embodiment of the present invention.

18 is a block diagram illustrating components of a wireless device for implementing the present invention.

The construction, operation, and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which technical features of the present invention are applied to a 3GPP system.

Although the present specification describes an embodiment of the present invention using an LTE system, an LTE-A system, and an NR system, the embodiment of the present invention as an example may be applied to any communication system corresponding to the above definition.

In addition, the specification of the base station may be used as a generic term including a remote radio head (RRH), an eNB, a transmission point (TP), a reception point (RP), a relay, and the like.

The 3GPP-based communication standard provides downlink physical channels corresponding to resource elements carrying information originating from an upper layer and downlink corresponding to resource elements used by the physical layer but not carrying information originating from an upper layer. Physical signals are defined. For example, a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), a physical multicast channel (PMCH), a physical control format indicator channel (physical control) format indicator channel (PCFICH), physical downlink control channel (PDCCH) and physical hybrid ARQ indicator channel (PHICH) are defined as downlink physical channels, reference signal and synchronization signal Is defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal of a predefined special waveform that the gNB and the UE know from each other. For example, a cell specific RS, UE- UE-specific RS, positioning RS (PRS), and channel state information RS (CSI-RS) are defined as downlink reference signals. The 3GPP LTE / LTE-A standard corresponds to uplink physical channels corresponding to resource elements carrying information originating from a higher layer and resource elements used by the physical layer but not carrying information originating from an upper layer. Uplink physical signals are defined. For example, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH) are the uplink physical channels. A demodulation reference signal (DMRS) for uplink control / data signals and a sounding reference signal (SRS) used for uplink channel measurement are defined.

In the present invention, Physical Downlink Control CHannel (PDCCH) / Physical Control Format Indicator CHannel (PCFICH) / PHICH (Physical Hybrid automatic retransmit request Indicator CHannel) / PDSCH (Physical Downlink Shared CHannel) are respectively DCI (Downlink Control Information) / CFI ( Means a set of time-frequency resources or a set of resource elements that carry downlink format ACK / ACK / NACK (ACKnowlegement / Negative ACK) / downlink data, and also a physical uplink control channel (PUCCH) / physical (PUSCH). Uplink Shared CHannel / PACH (Physical Random Access CHannel) means a set of time-frequency resources or a set of resource elements that carry uplink control information (UCI) / uplink data / random access signals, respectively. PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH RE or the time-frequency resource or resource element (RE) assigned to or belonging to PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH, respectively. PDCCH / PCFICH / PHICH / PDSCH / PUCCH / PUSCH / PRACH Resource In the following, the expression that the user equipment transmits PUCCH / PUSCH / PRACH is used for uplink control information / uplink on or through PUSCH / PUCCH / PRACH, respectively. It is used in the same sense as transmitting a data / random access signal, and the expression that the gNB transmits PDCCH / PCFICH / PHICH / PDSCH is used for downlink data / control information on or through PDCCH / PCFICH / PHICH / PDSCH, respectively. It is used in the same sense as sending it.

Hereinafter, an OFDM symbol / subcarrier / RE to which CRS / DMRS / CSI-RS / SRS / UE-RS is assigned or configured is configured as CRS / DMRS / CSI-RS / SRS / UE-RS symbol / carrier. It is called / subcarrier / RE. For example, an OFDM symbol assigned or configured with a tracking RS (TRS) is referred to as a TRS symbol, and a subcarrier assigned or configured with a TRS is called a TRS subcarrier and is assigned a TRS. Alternatively, the configured RE is called a TRS RE. Also, a subframe configured for TRS transmission is called a TRS subframe. Also, a subframe in which a broadcast signal is transmitted is called a broadcast subframe or a PBCH subframe, and a subframe in which a sync signal (for example, PSS and / or SSS) is transmitted is a sync signal subframe or a PSS / SSS subframe. It is called. An OFDM symbol / subcarrier / RE to which PSS / SSS is assigned or configured is referred to as a PSS / SSS symbol / subcarrier / RE, respectively.

In the present invention, the CRS port, the UE-RS port, the CSI-RS port, and the TRS port are respectively an antenna port configured to transmit CRS, an antenna port configured to transmit UE-RS, An antenna port configured to transmit CSI-RS and an antenna port configured to transmit TRS. Antenna ports configured to transmit CRSs can be distinguished from each other by the location of REs occupied by the CRS according to the CRS ports, and antenna ports configured to transmit UE-RSs The antenna ports configured to transmit the CSI-RSs can be distinguished from each other by the positions of the REs occupied by the UE-RS according to the -RS ports, and the CSI-RSs occupy They can be distinguished from each other by the location of the REs. Therefore, the term CRS / UE-RS / CSI-RS / TRS port may be used as a term for a pattern of REs occupied by CRS / UE-RS / CSI-RS / TRS in a certain resource region.

FIG. 1 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard. The control plane refers to a path through which control messages used by a user equipment (UE) and a network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted.

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to the upper layer of the medium access control layer through a transport channel. Data moves between the medium access control layer and the physical layer through the transmission channel. Data moves between the physical layer between the transmitting side and the receiving side through the physical channel. The physical channel utilizes time and frequency as radio resources. In detail, the physical channel is modulated in an Orthogonal Frequency Division Multiple Access (OFDMA) scheme in downlink, and modulated in a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme in uplink.

The medium access control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The function of the RLC layer may be implemented as a functional block inside the MAC. The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit IP packets such as IPv4 or IPv6 in a narrow bandwidth wireless interface.

The Radio Resource Control (RRC) layer located at the bottom of the third layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in connection with configuration, reconfiguration, and release of radio bearers. The radio bearer refers to a service provided by the second layer for data transmission between the terminal and the network. To this end, the RRC layers of the UE and the network exchange RRC messages with each other. If there is an RRC connected (RRC Connected) between the UE and the RRC layer of the network, the UE is in an RRC connected mode, otherwise it is in an RRC idle mode. The non-access stratum (NAS) layer above the RRC layer performs functions such as session management and mobility management.

The downlink transmission channel for transmitting data from the network to the UE includes a broadcast channel (BCH) for transmitting system information, a paging channel (PCH) for transmitting a paging message, and a downlink shared channel (SCH) for transmitting user traffic or a control message. have. Traffic or control messages of a downlink multicast or broadcast service may be transmitted through a downlink SCH or may be transmitted through a separate downlink multicast channel (MCH). The uplink transmission channel for transmitting data from the terminal to the network includes a random access channel (RAC) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or a control message. Above the transmission channel, the logical channel mapped to the transmission channel includes a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and an MTCH (multicast). Traffic Channel).

FIG. 2 is a diagram for explaining physical channels used in a 3GPP system and a general signal transmission method using the same.

If the UE is powered on or enters a new cell, the UE performs an initial cell search operation such as synchronizing with the base station (S201). To this end, the terminal may receive a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station to synchronize with the base station and obtain information such as a cell ID. have. Thereafter, the terminal may receive a physical broadcast channel from the base station to obtain broadcast information in a cell. Meanwhile, the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE acquires more specific system information by receiving a physical downlink control channel (PDSCH) according to a physical downlink control channel (PDCCH) and information on the PDCCH. It may be (S202).

On the other hand, when the first access to the base station or there is no radio resource for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (steps S203 to S206). To this end, the UE may transmit a specific sequence as a preamble through a physical random access channel (PRACH) (S203 and S205), and receive a response message for the preamble through the PDCCH and the corresponding PDSCH ( S204 and S206). In the case of contention-based RACH, a contention resolution procedure may be additionally performed.

After performing the above-described procedure, the UE performs a PDCCH / PDSCH reception (S207) and a physical uplink shared channel (PUSCH) / physical uplink control channel (Physical Uplink) as a general uplink / downlink signal transmission procedure. Control Channel (PUCCH) transmission (S208) may be performed. In particular, the terminal receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and the format is different according to the purpose of use.

Meanwhile, the control information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). ), And the like. In the 3GPP LTE system, the terminal may transmit the above-described control information such as CQI / PMI / RI through the PUSCH and / or PUCCH.

Meanwhile, the NR system considers a method using a high ultra-high frequency band, that is, a millimeter frequency band of 6 GHz or more, to transmit data while maintaining a high data rate to a large number of users using a wide frequency band. 3GPP uses this as the name NR, which is referred to as NR system in the present invention.

3 illustrates the structure of a radio frame used in NR.

In NR, uplink and downlink transmission are composed of frames. The radio frame has a length of 10 ms and is defined as two 5 ms half-frames (HFs). Half-frames are defined as five 1 ms subframes (SFs). The subframe is divided into one or more slots, and the number of slots in the subframe depends on the subcarrier spacing (SCS). Each slot includes 12 or 14 OFDM (A) symbols according to a cyclic prefix (CP). Usually when CP is used, each slot contains 14 symbols. If extended CP is used, each slot includes 12 symbols. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol), SC-FDMA symbol (or DFT-s-OFDM symbol).

Table 1 exemplarily shows that when the CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary according to the SCS.

SCS (15 * 2 ^ u)	N slot symb	N frame, u slot	N subframe, u slot
15KHz (u = 0)	14	10	One
30KHz (u = 1)	14	20	2
60KHz (u = 2)	14	40	4
120KHz (u = 3)	14	80	8
240KHz (u = 4)	14	160	16

* N ^slot _symb : Number of symbols in slot * N ^{frame, u} _slot : Number of slots in frame

* N ^{subframe, u} _slot : Number of slots in a ^subframe

Table 2 illustrates that when the extended CP is used, the number of symbols for each slot, the number of slots for each frame, and the number of slots for each subframe vary according to the SCS.

SCS (15 * 2 ^ u)	N slot symb	N frame, u slot	N subframe, u slot
60KHz (u = 2)	12	40	4

In the NR system, OFDM (A) numerology (eg, SCS, CP length, etc.) may be set differently among a plurality of cells merged into one UE. Accordingly, the (absolute time) section of a time resource (eg, SF, slot, or TTI) (commonly referred to as a time unit (TU) for convenience) composed of the same number of symbols may be set differently between merged cells. 4 illustrates a slot structure of an NR frame. The slot includes a plurality of symbols in the time domain. For example, one slot includes seven symbols in the case of a normal CP, but one slot includes six symbols in the case of an extended CP. The carrier includes a plurality of subcarriers in the frequency domain. Resource block (RB) is defined as a plurality of consecutive subcarriers (eg, 12) in the frequency domain. The bandwidth part (BWP) is defined as a plurality of consecutive (P) RBs in the frequency domain and may correspond to one numerology (eg, SCS, CP length, etc.). The carrier may include up to N (eg, 5) BWPs. Data communication is performed through an activated BWP, and only one BWP may be activated by one UE. Each element in the resource grid is referred to as a resource element (RE), one complex symbol may be mapped.

5 illustrates the structure of a self-contained slot. In an NR system, a frame is characterized by a self-complete structure in which a DL control channel, DL or UL data, UL control channel, and the like can be included in one slot. For example, the first N symbols in a slot may be used to transmit a DL control channel (hereinafter DL control region), and the last M symbols in the slot may be used to transmit a UL control channel (hereinafter UL control region). N and M are each an integer of 0 or more. A resource region (hereinafter, referred to as a data region) between the DL control region and the UL control region may be used for DL data transmission or may be used for UL data transmission. As an example, the following configuration may be considered. Each interval is listed in chronological order.

1.DL only configuration

2.UL only configuration

3. Mixed UL-DL Configuration

DL area + Guard Period (GP) + UL control area

DL control area + GP + UL area

DL area: (i) DL data area, (ii) DL control area + DL data area

UL region: (i) UL data region, (ii) UL data region + UL control region

The PDCCH may be transmitted in the DL control region, and the PDSCH may be transmitted in the DL data region. PUCCH may be transmitted in the UL control region, and PUSCH may be transmitted in the UL data region. Downlink control information (DCI), for example, DL data scheduling information, UL data scheduling information, and the like may be transmitted in the PDCCH. In PUCCH, uplink control information (UCI), for example, positive acknowledgment / negative acknowledgment (ACK / NACK) information, channel state information (CSI) information, and scheduling request (SR) for DL data may be transmitted. The GP provides a time gap in the process of the base station and the terminal switching from the transmission mode to the reception mode or from the reception mode to the transmission mode. Some symbols at the time of switching from DL to UL in the subframe may be set to GP.

Meanwhile, the NR system considers a method using a high ultra-high frequency band, that is, a millimeter frequency band of 6 GHz or more, to transmit data while maintaining a high data rate to a large number of users using a wide frequency band. 3GPP uses this as the name NR, which is referred to as NR system in the present invention. However, the millimeter frequency band has a frequency characteristic that the signal attenuation with the distance is very rapid due to the use of a frequency band too high. Therefore, NR systems using bands of at least 6 GHz or more narrow beams that solve the problem of reduced coverage due to abrupt propagation attenuation by collecting and transmitting energy in a specific direction rather than omnidirectionally to compensate for abrupt propagation characteristics. narrow beam) transmission scheme. However, when only one narrow beam is used for service, since a base station narrows the service range, the base station collects a plurality of narrow beams to serve a broadband service.

In the millimeter frequency band, that is, the millimeter wave (mmW) band, the wavelength is shortened to allow the installation of a plurality of antenna elements in the same area. For example, in a 30 GHz band with a wavelength of about 1 cm, a total of 100 antenna elements can be installed in a two-dimension arrangement in 0.5 lambda (wavelength) intervals on a panel of 5 by 5 cm. Do. Therefore, in mmW, it is considered to use a plurality of antenna elements to increase the beamforming gain to increase coverage or to increase throughput.

As a method for forming a narrow beam in the millimeter frequency band, a beamforming scheme in which a base station or a UE transmits the same signal by using a phase difference appropriate to a large number of antennas is mainly considered. Such beamforming methods include digital beamforming that creates a phase difference in a digital baseband signal, analog beamforming that uses a time delay (ie, cyclic shift) in a modulated analog signal to create a phase difference, digital beamforming, and an analog beam. Hybrid beamforming using both the forming and the like. Having a transceiver unit (TXRU) to enable transmission power and phase adjustment for each antenna element enables independent beamforming for each frequency resource. However, there is a problem in that it is not effective in terms of price to install TXRU in all 100 antenna elements. In other words, the millimeter frequency band should be used by a large number of antennas to compensate for rapid propagation attenuation, and digital beamforming is equivalent to the number of antennas, so RF components (eg, digital-to-analog converters (DACs), mixers, power Since an amplifier (power amplifier, linear amplifier, etc.) is required, there is a problem in that the cost of a communication device increases in order to implement digital beamforming in the millimeter frequency band. Therefore, when a large number of antennas are required, such as the millimeter frequency band, the use of analog beamforming or hybrid beamforming is considered. The analog beamforming method maps a plurality of antenna elements to one TXRU and adjusts the beam direction with an analog phase shifter. Such an analog beamforming method has a disadvantage in that only one beam direction can be made in the entire band and thus frequency selective beamforming (BF) cannot be performed. Hybrid BF is an intermediate form between digital BF and analog BF, with B TXRUs, which is fewer than Q antenna elements. In the case of the hybrid BF, although there are differences depending on the connection scheme of the B TXRU and the Q antenna elements, the direction of beams that can be simultaneously transmitted is limited to B or less.

As mentioned above, digital beamforming processes the digital baseband signal to be transmitted or received so that multiple beams can be used to transmit or receive signals simultaneously in multiple directions, while analog beamforming can transmit or receive signals. Since beamforming is performed in a modulated state of the received analog signal, the signal cannot be simultaneously transmitted or received in multiple directions beyond the range covered by one beam. In general, a base station communicates with a plurality of users at the same time by using a broadband transmission or a multi-antenna characteristic. When a base station uses analog or hybrid beamforming and forms an analog beam in one beam direction, due to the characteristics of analog beamforming Only users within the same analog beam direction can communicate. The RACH resource allocation and resource utilization scheme of the base station according to the present invention to be described later is proposed to reflect the constraints caused by the analog beamforming or hybrid beamforming characteristics.

FIG. 6 abstractly illustrates a hybrid beamforming structure in terms of a transceiver unit (TXRU) and a physical antenna.

When multiple antennas are used, a hybrid beamforming technique that combines digital beamforming and analog beamforming has emerged. In this case, analog beamforming (or RF beamforming) refers to an operation in which a transceiver (or RF unit) performs precoding (or combining). In hard-brid beamforming, the baseband unit and transceiver (or RF unit) perform precoding (or combining), respectively, resulting in the number of RF chains and the D / A (or A / D) converter. It is advantageous in that the performance of approaching digital beamforming can be reduced while reducing the number of. For convenience, the hybrid beamforming structure may be represented by N TXRUs and M physical antennas. The digital beamforming for the L data layers to be transmitted at the transmitting end can be represented by an N-by-L matrix, and then the converted N digital signals are converted into analog signals via TXRU and then into an M-by-N matrix. The expressed analog beamforming is applied. In FIG. 6, the number of digital beams is L, and the number of analog beams is N. In FIG. Furthermore, in the NR system, the base station is designed to change the analog beamforming on a symbol basis, so that a direction for supporting more efficient beamforming for a UE located in a specific area is being considered. Furthermore, when N TXRUs and M RF antennas are defined as one antenna panel, the NR system considers to introduce a plurality of antenna panels to which hybrid beamforming independent of each other is applicable. As such, when the base station utilizes a plurality of analog beams, the analog beams advantageous for signal reception may be different for each UE, and thus, the base station is applied to at least a synchronization signal, system information, and paging in a specific slot or subframe (SF). A beam sweeping operation is considered in which a plurality of analog beams to be changed symbol by symbol so that all UEs have a reception opportunity.

7 is a diagram illustrating a beam sweeping operation for a synchronization signal and system information during downlink transmission. In FIG. 7, a physical resource or a physical channel through which system information of the New RAT system is broadcasted is referred to as a physical broadcast channel (xPBCH). In this case, analog beams belonging to different antenna panels may be simultaneously transmitted in one symbol, and to measure a channel for each analog beam, as shown in FIG. A method of introducing Beam RS (BRS), which is a reference signal (RS) transmitted for a single analog beam, has been discussed. The BRS may be defined for a plurality of antenna ports, and each antenna port of the BRS may correspond to a single analog beam. In this case, unlike the BRS, a synchronization signal or a xPBCH may be transmitted for all the analog beams included in the analog beam group so that any UE can receive them well.

Tx - Rx  Beam association

The network refers to a measurement reference signal (MRS), beam reference to which each beam is applied, in order to allow the UE to perform measurements on beams used in the cell or available to the eNB. A known signal such as a beam reference signal (BRS) and a beamformed channel state information reference signal (CSI-RS) may be configured. Hereinafter, known signals are collectively referred to as BRS for convenience of description.

The base station may transmit the BRS aperiodically / periodically, and the UE may select an eNB Tx beam suitable for the UE through a measurement of the BRS. In consideration of the Rx beam of the UE, the UE may perform measurement using different Rx beams and select beam combinations considering the Tx beam of the eNB and the Rx beam of the UE. After performing such a process, the Tx-Rx beam association between the eNB and the UE may be determined explicitly or implicitly.

1) Network decision based beam association

The network may instruct the UE to report the top X Tx-Rx beam combinations as a result of the measurement. In this case, the number of beam combinations to report may be previously defined, transmitted by a network through higher layer signaling, or the like, or all beam combinations whose measurement results exceed a specific threshold may be reported.

In this case, a specific threshold may be predefined or signaled by the network. When decoding performance is different for each UE, a category considering the decoding performance of the UE is defined, and a threshold for each category is defined. It may be.

In addition, reporting on beam combinations may be performed by the network's instructions periodically or aperiodically. Alternatively, event-triggered reporting may be performed when previous reporting results and current measurement results change more than a certain level. At this time, a certain level may be predefined or the network may signal through an upper layer.

Meanwhile, the UE may report one or more beam associations determined by the above-described scheme. When multiple beam indexes are reported, priority may be given for each beam. For example, it may be reported to be interpreted in the form of 1 ^st preferred beam, 2 ^nd preferred beam, 쪋.

2) UE decision based beam association

Preferred beam reporting of the UE in beam association based UE determination may be performed in the same manner as the explicit beam association proposed above.

QCL (Quasi-Co Location)

The UE may receive a list containing up to M TCI-status settings for decoding the PDSCH according to the detected PDCCH having the DCI intended for the UE and a given cell. Here, M depends on UE capability.

Each TCI-State includes a parameter for establishing a QCL relationship between one or two DL RSs and a DM-RS port of a PDSCH. The QCL relationship is established with the RRC parameters qcl-Type1 for the first DL RS and qcl-Type2 (if set) for the second DL RS.

The QCL type corresponding to each DL RS is given by the parameter 'qcl-Type' in QCL-Info, and can take one of the following values:

'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}

-'QCL-TypeB': {Doppler shift, Doppler spread}

-'QCL-TypeC': {Doppler shift, average delay}

'QCL-TypeD': {Spatial Rx parameter}

For example, if the target antenna port is a specific NZP CSI-RS, the corresponding NZP CSI-RS antenna ports may be indicated / set as a specific TRS in QCL-Type A view and a specific SSB and QCL in QCL-Type D view. have. The UE receiving this indication / setting receives the corresponding NZP CSI-RS using the Doppler and delay values measured in the QCL-TypeA TRS, and applies the reception beam used to receive the QCL-TypeD SSB to the corresponding NZP CSI-RS reception. can do.

CSI Feedback

In the 3GPP LTE (-A) system, a user equipment (UE) has been defined to report channel state information (CSI) to a base station (BS). The channel state information (CSI) refers to information that may indicate the quality of a radio channel (also called a link) formed between the UE and the antenna port. For example, a rank indicator (RI), a precoding matrix indicator (PMI), a channel quality indicator (CQI), and the like may correspond to this. Here, RI represents rank information of a channel, which means the number of streams that a UE receives through the same time-frequency resource. Since this value is determined dependent on the long term fading of the channel, it is fed back from the UE to the BS with a period that is usually longer than PMI, CQI. PMI is a value reflecting channel spatial characteristics and indicates a precoding index preferred by the UE based on a metric such as SINR. CQI is a value indicating the strength of a channel and generally refers to a reception SINR obtained when a BS uses PMI.

In the 3GPP LTE (-A) system, the base station may configure a plurality of CSI processes to the UE, and receive and report the CSI for each process. Here, the CSI process consists of a CSI-RS for signal quality measurement from a base station and a CSI-interference measurement (CSI-IM) resource for interference measurement.

In LTE RRM  (Radio Resource Management) Measurement

In LTE systems, power control, scheduling, cell search, cell reselection, handover, radio link or connection monitoring, and connectivity It supports RRM operations including connection establishment / re-establish. In this case, the serving cell may request, from the UE, RRM measurement information, which is a measurement value for performing an RRM operation. In particular, in the LTE system, the UE can measure and report information such as cell search information, reference signal received power (RSRP), and reference signal received quality (RSRQ) for each cell. Specifically, in the LTE system, the UE receives 'measConfig' as a higher layer signal for RRM measurement from the serving cell. Then, the UE measures RSRP or RSRQ according to the information of the 'measConfig'. Here, the definitions of RSRP, RSRQ and RSSI according to TS 36.214 document of the LTE system are as follows.

- RSRP: RSRP, the cell specific reference signal transmitted in the measurement bandwidth is defined as the linear average of the power contribution ([W]) of;; (RE Resource Element) resource elements of (Cell specific reference signal CRS) . In addition, CRS R0 according to TS 36.211 is used for RSRP determination. In some cases, CRS R1 may be further used to increase reliability. The reference point for RSRP should be the antenna connector of the UE, and if receive diversity is used, the reported RSRP value should not be lower than any of the individual diversity RSRPs.

RSRQ: RSRQ is defined as N * RSRP / (RSS of E-UTRA carrier). In this case, N is the number of RBs of the E-UTRA carrier RSSI measurement bandwidth. In this case, the measurement of 'N * RSRP' and the measurement of 'RSI of an E-UTRA carrier' are performed through the same resource block set (RB set).

The E-UTRA carrier RSSI collects reference symbols for antenna port 0 on N resource blocks derived from all sources including co-channel, adjacent channel interference, thermal noise, etc. of the serving and non-serving cells. It is obtained as a linear average value of the total received power measured only in the containing OFDM symbol.

If higher layer signaling indicates a particular subframe for performing RSRP measurement, RSSI is measured on all indicated OFDM symbols. Even at this time, the reference point for the RSRQ should be the antenna connector of the UE, and when the reception diversity is used, the reported RSRQ value should not be lower than the RSRQ of any one of the individual diversity.

RSSI: Received wide band power including noise and thermal noise generated within a bandwidth defined by a receiver pulse shaping filter. Even at this time, the reference point for the RSSI should be the antenna connector of the UE, and if the receive diversity is used, the reported RSSI value should not be lower than the RSSI of any of the individual diversity.

According to the above definition, in the case of intra-frequency measurement, a UE operating in the LTE system may use 6, 15, 25, 50 through an information element (IE) related to allowed measurement bandwidth transmitted in a system information block type 3 (SIB3). It is allowed to measure RSRP in the bandwidth corresponding to one of 75, 100, and 100 RB (resource block). In the case of inter-frequency measurement, RSRP is allowed to be measured in a bandwidth corresponding to one of 6, 15, 25, 50, 75, and 100 RB (resource block) through the allowed measurement bandwidth transmitted from SIB5. If there is no IE, RSRP can be measured in the frequency band of the entire downlink system by default. In this case, when the UE receives the allowed measurement bandwidth, the UE considers the value as the maximum measurement bandwidth and can freely measure the value of RSRP within the value.

However, if the serving cell transmits the IE defined by the WB-RSRQ and the Allowed measurement bandwidth is set to 50RB or more, the UE should calculate the RSRP value for the entire allowed measurement bandwidth. On the other hand, in the case of RSSI, RSSI is measured in the frequency band of the receiver of the UE according to the definition of the RSSI bandwidth.

NR communication systems are required to support significantly better performance than existing fourth generation (4G) systems in terms of data rate, capacity, latency, energy consumption and cost. Thus, NR systems need to make significant advances in the area of bandwidth, spectral, energy, signaling efficiency, and cost per bit.

8 shows an example of a wireless communication system supporting an unlicensed band applicable to the present invention.

In the following description, a cell operating in a licensed band (hereinafter referred to as L-band) is defined as an L-cell, and a carrier of the L-cell is defined as (DL / UL) LCC. In addition, a cell operating in an unlicensed band (hereinafter, referred to as a U-band) is defined as a U-cell, and a carrier of the U-cell is defined as (DL / UL) UCC. The carrier / carrier-frequency of the cell may refer to the operating frequency (eg, center frequency) of the cell. A cell / carrier (e.g., CC) is collectively referred to as a cell.

When the UE and the base station transmit and receive signals through the carrier-coupled LCC and the UCC as shown in FIG. 8A, the LCC may be set to PCC (Primary CC) and the UCC may be set to SCC (Secondary CC). As shown in (b) of FIG. 8, the terminal and the base station may transmit and receive signals through one UCC or a plurality of carrier-coupled UCCs. That is, the terminal and the base station can transmit and receive signals only through the UCC (s) without the LCC.

Hereinafter, the signal transmission / reception operation in the unlicensed band detailed in the present invention may be performed based on all the deployment scenarios described above (unless otherwise noted).

Meanwhile, the NR frame structure of FIG. 3 may be used for operation in the unlicensed band. The configuration of OFDM symbols occupied for uplink / downlink signal transmission in the frame structure for the unlicensed band may be set by the base station. In this case, the OFDM symbol may be replaced with an SC-FDM (A) symbol.

For downlink signal transmission through the unlicensed band, the base station can inform the terminal of the configuration of OFDM symbols used in subframe #n through signaling. Here, the subframe may be replaced with a slot or a time unit (TU).

In detail, in the LTE system supporting the unlicensed band, the UE transmits the subframe # through a specific field (eg, the Subframe configuration for LAA field) in the DCI received from the base station in subframe # n-1 or subframe #n. It is possible to assume (or identify) the configuration of OFDM symbols occupied in n.

Table 3 shows the configuration of OFDM symbols in which the Subframe configuration for LAA field is used for transmission of a downlink physical channel and / or physical signal in a current subframe and / or next subframe. The method to show is illustrated.

Value of '' Subframe  configuration for LAA '' field in current subframe	Configuration of occupied OFDM symbols (current subframe , next subframe )
0000	(-, 14)
0001	(-, 12)
0010	(-, 11)
0011	(-, 10)
0100	(-, 9)
0101	(-, 6)
0110	(-, 3)
0111	(14, *)
1000	(12,-)
1001	(11,-)
1010	(10,-)
1011	(9,-)
1100	(6,-)
1101	(3,-)
1110	reserved
1111	reserved
NOTE:-(-, Y) means UE may assume the first Y symbols are occupied in next subframe and other symbols in the next subframe are not occupied.- (X,-) means UE may assume the first X symbols are occupied in current subframe and other symbols in the current subframe are not occupied.- (X, *) means UE may assume the first X symbols are occupied in current subframe, and at least the first OFDM symbol of the next subframe is not occupied.

In order to transmit an uplink signal through an unlicensed band, the base station may inform the terminal of information about an uplink transmission interval through signaling.

In detail, in the LTE system supporting the unlicensed band, the UE may obtain 'UL duration' and 'UL offset' information for the subframe #n through the 'UL duration and offset' field in the detected DCI.

Table 4 illustrates how a UL duration and offset field indicates a UL offset and a UL duration configuration in an LTE system.

Value of 'UL duration and offset' field	UL offset, l (in subframes)	UL duration, d (in subframes)
00000	Not configured	Not configured
00001	One	One
00010	One	2
00011	One	3
00100	One	4
00101	One	5
00110	One	6
00111	2	One
01000	2	2
01001	2	3
01010	2	4
01011	2	5
01100	2	6
01101	3	One
01110	3	2
01111	3	3
10000	3	4
10001	3	5
10010	3	6
10011	4	One
10100	4	2
10101	4	3
10110	4	4
10111	4	5
11000	4	6
11001	6	One
11010	6	2
11011	6	3
11100	6	4
11101	6	5
11110	6	6
11111	reserved	reserved

For example, when the UL duration and offset field sets (or indicates) UL offset l and UL duration d for subframe #n, the UE may subframe # n + l + i (i = 0, 1, 쪋, There is no need to receive a downlink physical channel and / or a physical signal within d-1).

The base station may perform one of the following unlicensed band access procedures (eg, Channel Access Procedure, CAP) for downlink signal transmission in the unlicensed band.

(1) first downlink CAP method

9 is a flowchart illustrating a CAP operation for downlink signal transmission through an unlicensed band of a base station.

The base station may initiate a channel access procedure (CAP) for downlink signal transmission (eg, signal transmission including PDSCH / PDCCH / EPDCCH) through the unlicensed band (S910). The base station may arbitrarily select the backoff counter N in the contention window CW according to step 1. At this time, the N value is set to an initial value N _init (S920). N _init is selected as a random value among values between 0 and CW _p . Subsequently, if the backoff counter value N is 0 in step 4 (S930; Y), the base station terminates the CAP process (S932). Subsequently, the base station may perform Tx burst transmission including PDSCH / PDCCH / EPDCCH (S934). On the other hand, if the backoff counter value is not 0 (S930; N), the base station decreases the backoff counter value by 1 according to step 2 (S940). Subsequently, the base station checks whether the channel of the U-cell (s) is in the idle state (S950), and if the channel is in the idle state (S1150; Y), checks whether the backoff counter value is 0 (S930). On the contrary, if the channel is not idle in step S1150, that is, the channel is busy (S950; N), the base station according to step 5 has a delay duration T _d longer than the slot time (e.g., 9usec) (more than 25usec). It is checked whether the corresponding channel is in an idle state (S960). If the channel is idle in the delay period (S970; Y), the base station may resume the CAP process again. In this case, the delay period may include a 16usec interval and m _p consecutive slot times immediately following (eg, 9usec). On the other hand, if the channel is busy during the delay period (S970; N), the base station re-performs step S960 to check again whether the channel of the U-cell (s) is idle during the new delay period.

Table 5 illustrates the difference of m _p , minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW sizes applied to the CAP according to the channel access priority class. .

Channel Access Priority Class (p)	m p	CW min, p	CW max, p	T ultcot, p	Allowed CW p sizes
One	One	3	7	2 ms	{3,7}
2	One	7	15	3 ms	{7,15}
3	3	15	63	8 or 10 ms	{15,31,63}
4	7	15	1023	8 or 10 ms	{15,31,63,127,255,511,1023}

The contention window size applied to the first downlink CAP may be determined based on various methods. As an example, the contention window size may be adjusted based on the probability that HARQ-ACK values corresponding to PDSCH transmission (s) in a certain time interval (eg, reference TU) are determined to be NACK. When the base station performs downlink signal transmission including the PDSCH associated with the channel access priority class p on the carrier, HARQ-ACK values corresponding to the PDSCH transmission (s) in the reference subframe k (or reference slot k) are NACK. If the probability determined is at least Z = 80%, the base station increments the CW values set for each priority class to the next allowed one, respectively. Alternatively, the base station maintains the CW values set for each priority class as initial values. A reference subframe (or reference slot) may be defined as a start subframe (or start slot) in which the most recent signal transmission on a corresponding carrier for which at least some HARQ-ACK feedback is available.

(2) second downlink CAP method

The base station may perform downlink signal transmission (eg, signal transmission including discovery signal transmission and not including PDSCH) on the unlicensed band based on the second downlink CAP method described below.

If the length of the signal transmission interval of the base station is 1 ms or less, the base station transmits a downlink signal (eg, discovery signal transmission) through the unlicensed band immediately after the corresponding channel is sensed as idle for at least sensing period T _drs = 25 us. And a signal not including the PDSCH). Here, T _drs is composed of a section T _f (= 16us) immediately following one slot section T _sl = 9us.

(3) third downlink CAP method

The base station may perform the following CAP for downlink signal transmission through multiple carriers in the unlicensed band.

1) Type A: The base station performs CAP on the multiple carriers based on the counter N (counter N considered in the CAP) defined for each carrier, and performs downlink signal transmission based on this.

Type A1: Counter N for each carrier is determined independently of each other, and downlink signal transmission through each carrier is performed based on counter N for each carrier.

Type A2: A counter N for each carrier is determined as an N value for a carrier having the largest contention window size, and downlink signal transmission through the carrier is performed based on the counter N for each carrier.

2) Type B: A base station performs a CAP based on a counter N only for a specific carrier among a plurality of carriers, and performs downlink signal transmission by determining whether the channel is idle for the remaining carriers before transmitting a signal on the specific carrier. .

Type B1: A single contention window size is defined for a plurality of carriers, and the base station utilizes a single contention window size when performing a CAP based on counter N for a specific carrier.

Type B2: The contention window size is defined for each carrier, and the largest contention window size among the contention window sizes is used when determining the N _init value for a specific carrier.

On the other hand, the terminal performs a contention-based CAP for uplink signal transmission in the unlicensed band. The terminal performs Type 1 or Type 2 CAP for uplink signal transmission in the unlicensed band. In general, the terminal may perform a CAP (eg, Type 1 or Type 2) set by the base station for uplink signal transmission.

(1) Type 1 uplink CAP method

10 is a flowchart illustrating a type 1 CAP operation of a terminal for uplink signal transmission.

The terminal may initiate a channel access procedure (CAP) for signal transmission through the unlicensed band (S1010). The terminal may arbitrarily select the backoff counter N in the contention window CW according to step 1. At this time, the N value is set to an initial value N _init (S1020). N _init is selected from any value between 0 and CW _p . Subsequently, if the backoff counter value N is 0 in step 4 (S1030; Y), the terminal terminates the CAP process (S1032). Subsequently, the terminal may perform Tx burst transmission (S1034). On the other hand, if the backoff counter value is not 0 (S1030; N), the terminal decreases the backoff counter value by 1 according to step 2 (S1040). Subsequently, the terminal checks whether the channel of the U-cell (s) is in an idle state (S1050), and if the channel is in an idle state (S1050; Y), checks whether the backoff counter value is 0 (S1030). On the contrary, if the channel is not idle in step S1050, that is, if the channel is busy (S1050; N), the UE according to step 5 has a delay duration T _d longer than the slot time (eg, 9usec) (more than 25usec). It is checked whether the corresponding channel is in an idle state (S1060). If the channel is idle in the delay period (S1070; Y), the terminal can resume the CAP process. Here, the delay period may consist of a 16usec interval and m _p consecutive slot times immediately following (eg, 9usec). On the other hand, if the channel is busy during the delay period (S1070; N), the terminal re-performs step S1060 to check again whether the channel is idle for a new delay period.

Table 6 illustrates the difference of m _p , minimum CW, maximum CW, maximum channel occupancy time (MCOT) and allowed CW sizes applied to the CAP according to the channel access priority class. .

Channel Access Priority Class (p)	m p	CW min, p	CW max, p	T ultcot, p	allowed CW p sizes
One	2	3	7	2 ms	{3,7}
2	2	7	15	4 ms	{7,15}
3	3	15	1023	6 ms or 10 ms	{15,31,63,127,255,511,1023}
4	7	15	1023	6 ms or 10 ms	{15,31,63,127,255,511,1023}
NOTE1: For p = 3,4, Tultcot, p = 10ms if the higher layer parameter 'absenceOfAnyOtherTechnology-r14' indicates TRUE, otherwise, T ultcot, p = 6ms.NOTE 2: When T ultcot, p = 6ms it may be increased to 8 ms by inserting one or more gaps. The minimum duration of a gap shall be 100 μs. The maximum duration before including any such gap shall be 6 ms.

The contention window size applied to the Type 1 uplink CAP may be determined based on various methods. As an example, the contention window size may be adjusted based on whether to toggle a new data indicator (NDI) value for at least one HARQ processor associated with HARQ_ID_ref, which is a HARQ process ID of the UL-SCH within a predetermined time interval (eg, a reference TU). have. When the terminal performs signal transmission using a Type 1 channel access procedure related to the channel access priority class p on the carrier, if the UE toggles NDI values for at least one HARQ process associated with HARQ_ID_ref, all priority classes

for,

Set to, otherwise, all priority classes

Increase CW _p for the next higher allowed value.

The reference subframe n _ref (or reference slot n _ref ) is determined as follows.

UE receives UL grant in subframe (or slot) n _g and subframe (or slot)

In the case of performing transmission including a UL-SCH without a gap starting from a subframe (or slot) n ₀ within the subframe (or slot) n _w , the UE performs UL-SCH based on a Type 1 CAP. The most recent subframe (or slot) before the transmitted subframe (or slot) n _g -3, and the reference subframe (or slot) n _ref is a subframe (or slot) n ₀ .

(2) Type 2 uplink CAP method

When the UE uses a Type 2 CAP for transmitting an uplink signal (eg, a signal including a PUSCH) through an unlicensed band, the UE at least senses a duration.

During uplink (immediately after) after sensing that the channel is idle, an uplink signal (eg, a signal including a PUSCH) may be transmitted. T _{short _ul} is one slot interval

Immediately following (immediately followed)

It consists of. T _f includes an idle slot section T _sl at the start of the T _f .

11 illustrates an SSB structure. The UE may perform cell search, system information acquisition, beam alignment for initial access, DL measurement, etc. based on the SSB. SSB is mixed with a Synchronization Signal / Physical Broadcast channel (SS / PBCH) block.

Referring to FIG. 11, the SSB is composed of PSS, SSS, and PBCH. The SSB is composed of four consecutive OFDM symbols, and PSS, PBCH, SSS / PBCH, and PBCH are transmitted for each OFDM symbol. PSS and SSS consist of 1 OFDM symbol and 127 subcarriers, respectively, and PBCH consists of 3 OFDM symbols and 576 subcarriers. Polar coding and quadrature phase shift keying (QPSK) are applied to the PBCH. The PBCH consists of a data RE and a demodulation reference signal (DMRS) RE for each OFDM symbol. Three DMRS REs exist for each RB, and three data REs exist between DMRS REs.

The cell search refers to a process of acquiring time / frequency synchronization of a cell and detecting a cell ID (eg, physical layer cell ID, PCID) of the cell. PSS is used to detect a cell ID within a cell ID group, and SSS is used to detect a cell ID group. PBCH is used for SSB (time) index detection and half-frame detection.

The cell search process of the UE can be summarized as shown in Table 7 below.

	Type of signals		Operations
1 st step	PSS	* SS / PBCH block (SSB) symbol timing acquisition * Cell ID detection within a cell ID group (3 hypothesis)
2 nd Step	SSS	Cell ID group detection (336 hypothesis)
3 rd Step	PBCH DMRS	* SSB index and Half frame (HF) index (Slot and frame boundary detection)
4 th Step	PBCH	* Time information (80 ms, System Frame Number (SFN), SSB index, HF) * Remaining Minimum System Information (RMSI) Control resource set (CORESET) / Search space configuration
5 th Step	PDCCH and PDSCH	* Cell access information * RACH configuration

There are 336 cell ID groups, and three cell IDs exist for each cell ID group. There are a total of 1008 cell IDs. Information about a cell ID group to which a cell ID of a cell belongs is provided / obtained through the SSS of the cell, and information about the cell ID among the 336 cells in the cell ID is provided / obtained through the PSS.

12 illustrates SSB transmission. Referring to FIG. 12, SSBs are periodically transmitted according to SSB periods. The SSB basic period assumed by the UE in initial cell search is defined as 20 ms. After cell access, the SSB period may be set to one of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} by a network (eg, a base station). A set of SSB bursts is constructed at the beginning of the SSB period. The SSB burst set consists of a 5ms time window (ie, half-frame), and the SSB can be transmitted up to L times within the SS burst set. The maximum number of transmissions L of the SSB may be given as follows according to the frequency band of the carrier wave. One slot includes up to two SSBs.

-For frequency range up to 3 GHz, L = 4

-For frequency range from 3 GHz to 6 GHz, L = 8

-For frequency range from 6 GHz to 52.6 GHz, L = 64

The time position of the SSB candidate in the SS burst set may be defined as follows according to the SCS. The temporal position of the SSB candidate is indexed from 0 to L-1 in time order within the SSB burst set (ie, half-frame) (SSB index).

Case A-15 kHz SCS: The index of the start symbol of the candidate SSB is given by {2, 8} + 14 * n. N = 0, 1 when the carrier frequency is 3 GHz or less. N = 0, 1, 2, and 3 when the carrier frequency is 3 GHz to 6 GHz.

Case B-30 kHz SCS: The index of the start symbol of the candidate SSB is given by {4, 8, 16, 20} + 28 * n. N = 0 when the carrier frequency is 3 GHz or less. N = 0, 1 when the carrier frequency is 3 GHz to 6 GHz.

Case C-30 kHz SCS: The index of the start symbol of the candidate SSB is given by {2, 8} + 14 * n. N = 0, 1 when the carrier frequency is 3 GHz or less. N = 0, 1, 2, and 3 when the carrier frequency is 3 GHz to 6 GHz.

Case D-120 kHz SCS: The index of the start symbol of the candidate SSB is given by {4, 8, 16, 20} + 28 * n. If the carrier frequency is greater than 6 GHz, then n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

Case E-240 kHz SCS: The index of the start symbol of the candidate SSB is given by {8, 12, 16, 20, 32, 36, 40, 44} + 56 * n. If the carrier frequency is greater than 6 GHz, then n = 0, 1, 2, 3, 5, 6, 7, 8.

13 illustrates multi-beam transmission of the SSB.

Beam sweeping means that the Transmission Reception Point (TRP) (eg, base station / cell) varies the beam (direction) of the radio signal over time (hereinafter, the beam and beam direction may be mixed). Referring to FIG. 8, the SSB may be periodically transmitted using beam sweeping. In this case, the SSB index is implicitly linked with the SSB beam. The SSB beam may be changed in units of SSB (index) or in units of SSB (index) group. In the latter case, the SSB beam remains the same within the SSB (index) group. That is, the transmission beam reflections of the SSB are repeated in a plurality of consecutive SSBs. The maximum number of transmissions L of the SSB in the SSB burst set has a value of 4, 8 or 64 depending on the frequency band to which the carrier belongs. Accordingly, the maximum number of SSB beams in the SSB burst set may also be given as follows according to the frequency band of the carrier.

-For frequency range up to 3 GHz, Max number of beams = 4

-For frequency range from 3 GHz to 6 GHz, Max number of beams = 8

-For frequency range from 6 GHz to 52.6 GHz, Max number of beams = 64

However, when multi-beam transmission is not applied, the number of SSB beams is one.

When the terminal attempts to initially access the base station, the terminal may align the beam with the base station based on the SSB. For example, the terminal identifies the best SSB after performing SSB detection. Thereafter, the terminal may transmit the RACH preamble to the base station using the PRACH resources linked / corresponding to the index (ie, beam) of the best SSB. SSB may be used to align the beam between the base station and the terminal even after the initial access.

14 illustrates a method of notifying an SSB (SSB_tx) that is actually transmitted.

Up to L SSBs may be transmitted in the SSB burst set, and the number / locations of the SSBs actually transmitted may vary by base station / cell. The number / location at which the SSB is actually transmitted is used for rate-matching and measurement, and information about the SSB actually transmitted is indicated as follows.

In the case of rate-matching: it may be indicated through UE-specific RRC signaling or RMSI. UE-specific RRC signaling includes a full (eg, length L) bitmap in both the below 6 GHz and above 6 GHz frequency ranges. On the other hand, the RMSI includes a full bitmap below 6GHz and a compressed bitmap as shown above. Specifically, information about the SSB actually transmitted using the group-bit map (8 bits) + the intra-group bitmap (8 bits) can be indicated. Here, resources indicated by UE-specific RRC signaling or RMSI (eg, RE) may be reserved for SSB transmission, and PDSCH / PUSCH and the like may be rate-matched in consideration of SSB resources.

In the case of measurement: When in the RRC connected mode, the network (eg, base station) may indicate the set of SSBs to be measured within the measurement interval. The SSB set may be indicated for each frequency layer. If there is no indication about the SSB set, the default SSB set is used. The default SSB set includes all SSBs within the measurement interval. The SSB set may be indicated using a full (eg, length L) bitmap of RRC signaling. When in RRC idle mode, a default set of SSBs is used.

In a conventional NR system, a UE measures a size or quality of a signal received from a neighbor cell using an SS / PBCH block or a CSI-RS for a neighbor cell and reports it to a base station. In this case, RSRP (Reference Signal Received Power) is generally used as a value for the signal size, and RSRQ (Reference Signal Received Quality) or SINR (Signal-to-Interference & Noise Ratio) is used for the signal quality. ).

The base station determines a cell to camp on based on the size and quality of the signal for each cell or beam, and if necessary, instructs the terminal to handover to a suitable cell through a handover command. .

At this time, the base station defines in advance the SS / PBCH block and the CSI-RS reference signal for RSRP measurement of the terminal or transmits at the time set by the base station.

Therefore, when the UE is confirmed that the cell is present and receives the resource information of the SS / PBCH block or the CSI-RS, the UE measures the RSRP value and reports it to the higher layer based on this. At this time, if the signal transmitted through the cell is too small or the signal quality is not detected because the signal is not detected, the upper layer performs filtering by reporting that no signal is detected from the cell. It can help.

Hereinafter, for convenience of description, the SS / PBCH block and the CSI-RS are collectively called RRM-RS (Radio Resource Measurement-Reference Signal).

If the NR system is operating in an unlicensed band (hereinafter referred to as the NR-U system), the NR system may coexist in the same frequency band as other RATs such as WiFi, so that the frequency bands of different frequency bands before transmitting the signal. Alternatively, a channel clearance assessment (CCA) is performed to check whether the network is not used in advance by another provider network. Thereafter, if the channel is occupied, the signal is not transmitted, and the signal can be transmitted only when the channel is not occupied, which is called LBT (Listen Before Talk).

In the NR-U system, the LBT process is performed for signal transmission also with respect to the reference signal for performing the above-described RRM measurement. Therefore, when another system around the base station occupies the channel in advance, the UE measures the neighbor cell without knowing whether the RRM-RS for performing the measurement of the neighbor cell has been transmitted. measurement).

Therefore, even though the RRM-RS is not actually transmitted by the LBT, the UE may determine that the RRM-RS corresponds to 'no RRM-RS detected' regarding the size and quality of the measured RRM-RS. In other words, even though the RRM-RS is not actually transmitted by the LBT, the UE may not detect the RRM-RS on the premise that the RRM-RS is transmitted, thereby determining that the size and quality of the RRM-RS are not good.

That is, if the link between the cell and the terminal is good and the RRM-RS is actually transmitted, the RRM-RS is transmitted by another RAT such as WiFi even though a high RRM-RS size and quality could be measured. If the RRM-RS is not transmitted due to the occupied frequency, the UE may not recognize that the RRM-RS has not been transmitted due to the frequency occupancy of another RAT. Therefore, the UE may simply determine that the RRM-RS is not transmitted or that the link between the cell and the UE is not good, and thus an error in the RRM measurement determination may occur.

However, when the size and quality of the signal are different from the judgment of the terminal as described above, when the size and quality of the signal as described above are not reported to the upper layer, the result of filtering at the higher layer is actually It can cause errors in signal size and quality. In addition, due to this, a time for reporting the size and quality of the RRM-RS to the base station may be delayed or an error may occur in the information about the size and quality of the reported RRM-RS.

Therefore, to solve this problem, the UE should be able to determine that the RRM-RS has not been transmitted by the LBT and report it to a higher layer. In addition, the upper layer should not perform L3 filtering on the measurement value corresponding to the RRM-RS not transmitted by the LBT.

In addition, an error may occur when the UE acquires information related to the LBT operation of the cell. Even in this case, there may be a problem that the time for signal quality reporting is delayed, such as the UE reporting the size and quality of the RRM-RS to the upper layer regardless of the LBT operation of the actual base station.

Therefore, the present invention will be described with respect to the method that the terminal can recognize when the cell fails to transmit the RRM-RS due to the LBT and the operations of the terminal using the same.

15 shows an operation process of a terminal according to the present invention. Referring to FIG. 15, the terminal receives information related to RRM-RS transmission. At this time, the information related to the RRM-RS transmission may be defined according to the first embodiment (S1501). In addition, the signal or channel used to transmit and receive information related to the RRM-RS transmission, according to the second embodiment, the sequence within the PBCH (Physical Broadcast Channel) payload, SMTC (SS / PBCH Block Measurement Time Configuration) window Based signal and / or downlink control information (DCI) may be utilized.

Upon receiving the information related to the RRM-RS transmission, the terminal may perform a specific operation for at least one of the embodiments described in the third embodiment based on the third embodiment using the information related to the RRM-RS transmission. There is (S1503).

16 is a view for explaining the operation of the base station according to the present invention. Referring to FIG. 16, the base station transmits information related to RRM-RS transmission to the terminal. In this case, information related to RRM-RS transmission may be defined according to the first embodiment (S1601). And, the base station can transmit and receive information related to the RRM-RS using a signal or channel of the type according to the second embodiment.

In addition, the base station may receive a report on the result value measured using the RRM-RS from the terminal (S1603). However, step S1603 is not always performed, and may be limited to the case where the UE determines to transmit the measurement report for the neighbor cell based on the third embodiment. In addition, in step S1603, the base station may perform necessary operations according to the third embodiment, in addition to receiving the measurement result using the RRM-RS. For example, according to the third embodiment, the terminal may perform an operation such as handover or frequency redirection.

17 is a view for explaining the operation of the network according to the present invention. Referring to FIG. 17, the base station transmits information related to RRM-RS transmission according to the first embodiment to the terminal by using the signal and the channel according to the second embodiment (S1701).

The UE may perform an operation related to RRM based on the information related to the RRM-RS transmission, and the operation related to the RRM may be performed based on the third embodiment (S1703). And, if necessary, the terminal may report the RRM measurement result to the base station (S1705).

Embodiment 1: Information on LBT Operation and Information Delivery Related to LBT Operation

In order to solve the above problem, the present invention proposes that the base station delivers information on the RRM-RS transmission delay by the LBT to the terminal. That is, the base station transmits a signal defined in the RRM-RS or an SMTC window in which the SS / PBCH block is transmitted, such as a PBCH payload defined in the SS / PBCH block, whether or not the RRM-RS is transmitted by the LBT. Like a separate signal, the above-described information about the RRM-RS transmission delay by the LBT may be transmitted to the terminal through a signal other than the RRM-RS.

Meanwhile, the information on the RRM-RS transmission delay may be as follows.

1) Embodiment 1-1: Information on Number of RRM-RS Transmissions

The base station defines a transmission counter and increments the transmission counter each time the RRM-RS is transmitted through the LBT process. The base station may transmit information about the increased transmission counter to the terminal.

For example, define a three-bit transmission counter, increase the value of the transmission counter by one each time the RRM-RS transmission is successful, and if the RRM-RS transmission is successful when the value of the current transmission counter is 7, the transmission counter The value returns to zero again.

At this time, when the terminal determines that the RRM-RS is transmitted through the measurement of the signal size and quality, the terminal increases the receiving counter and obtains information on the transmitted counter as the base station. Thereafter, if the reception counter matches the obtained transmission counter, it may be determined that there is no detection error for the LBT operation.

However, if the reception counter and the transmission counter are inconsistent, the terminal may determine that there is a detection error for the LBT operation, and may correct the filtering result of the upper layer by using values of the previously measured signal size and quality. . In addition, independent of the correction for the filtering, the UE may use the determination of the match / dismatch between the reception counter and the transmission counter to correct the parameter for determining the LBT operation and the result of the base station. On the other hand, the correction for this parameter, it is possible to increase the accuracy of the information on whether the LBT is performed.

In addition, the terminal may derive statistics related to the RRM-RS transmission delay by the LBT using the information related to the LBT operation described above. As discussed below, the terminal may be used to determine a cell or frequency band to camp on using the above-described statistical value.

On the other hand, in order for the terminal to accurately interpret the information on the transmission counter transmitted by the base station, it is necessary to inform the terminal in advance of the transmission period of the RRM-RS. However, the period of the measurement (measurement) through the RRM-RS transmitted to the terminal may be different from the RRM-RS transmission period transmitted by the actual base station.

In this case, the terminal may increase the value of the transmission counter received while performing the measurement for the RRM-RS to a value outside the expected range of the terminal. Therefore, the base station needs to inform the terminal of the RRM-RS transmission period together with the measurement period through the RRM-RS in order to eliminate ambiguity of the terminal operation. At this time, the measurement period through the RRM-RS may be an SMTC window period in the NR system, the RRM-RS transmission period may be a counting period of the transmission counter.

As described above, if the RRM-RS measurement cycle and the RRM-RS transmission cycle are known, the terminal may expect the transmission counter value of the RRM-RS. For example, when the period of the SMTC window is 40ms and the counting period of the transmission counter is 20ms, the UE determines that the RRM-RS transmission is dropped by the LBT operation in the step of measuring RSRP in the SMTC window. Assume the case. In this case, when RSRP is measured in the next SMTC window and a corresponding transmission counter value is obtained, if the value of the transmission counter is 4, it is determined that dropping prediction by LBT is incorrect, and the transmission counter is incorrect. If the value of is smaller than 4, it can be recognized that the dropping prediction by the LBT operation is correct.

However, even in this case, the UE predicts that the RRM-RS transmission is dropped by the LBT in measuring the RSRP, and even if the transmission counter value is 3, this should be transmitted in the SMTC window set by the terminal. It may not be clear whether the RRM-RS has been dropped. To this end, the terminal reads the transmission counter value in accordance with the actual transmission period of the RRM-RS, it can be sure whether the dropping of the RRM-RS in the set SMTC window, but this burdens the terminal to perform unnecessary operations Is given.

Therefore, bitmap information indicating whether to transmit the RRM-RS corresponding to the counting period of the RRM-RS transmission counter may be transmitted to the terminal together with the information on the transmission counter. Alternatively, such bitmap information may be transmitted to the terminal in place of the information on the transmission counter. In this case, when the UE measures the RRM-RS in the SMTC window, the terminal may read the received RRM-RS transmission bitmap information to more accurately know whether the RRM-RS is transmitted, and as described above. Calibration or optimization of the measurement results can be performed.

2) Embodiment 1-2: Delivery of Statistical Information on Whether to Delay RRM-RS Transmission for RRM-RS or All DL Burst

The transfer of information on the transmission counter described in the embodiment 1-1 is basically used to determine a detection error for the LBT operation, to correct the LBT operation or to compensate for the signal size and quality values filtered by the upper layer. The main purpose is to.

However, in order to use cell selection or frequency selection by using the RRM-RS transmission delay statistics by LBT, the base station transmits transmission counter information on the RRM-RS to the terminal. Rather, the UE transmits statistical information about the RRM-RS transmission delay or transmission success for the entire downlink transmission opportunity (that is, the downlink burst) including the RRM-RS transmission by the LBT to the terminal for a predetermined time. It may be advantageous to use.

Of course, the base station transmits a transmission counter for the RRM-RS to the terminal, it is also possible for the terminal to derive a statistical value using it. However, a transmission counter may be used to derive overall statistics only when the transmission time of a signal such as an RRM-RS is known to the terminal in advance.

Therefore, when the base station wants the UE to use the LBT success probability for the entire downlink burst, such as cell selection or frequency selection, the transmission counter for the RRM-RS according to the embodiment 1-1 Using a transmission counter can be difficult. In addition, when the LBT parameters for the RRM-RS are different between the base station and the terminal, a difference in statistics related to the LBT between the base station and the terminal may occur. In addition, when the transmission period of the RRM-RS is too long, the time for deriving the statistics is too long, so the transmission counter of the RRM-RS only may not be suitable for deriving the statistics.

Therefore, the base station determines the probability of transmission due to LBT success of RRM-RS (or delay of RRM-RS transmission due to LBT failure) or probability of transmission due to LBT success of downlink burst (or delay of RRM-RS transmission due to LBT failure). It can be defined and delivered directly to the terminal. In this case, the information related to the delay probability by the LBT may be transmitted in a limited bit through quantization.

Example 2: LBT  Information about the behavior and LBT  Channels or signals to convey statistical information about the operation

Statistical information on the LBT operation obtained by the base station or a transmission counter value should be delivered to the terminal through an appropriate channel and signal. The statistical information or the transmission counter value for this LBT operation may be transmitted through different channels according to the characteristics of the information. Therefore, in Embodiment 2, a channel or signal for transmitting statistical information on the LBT operation is defined.

1) Example 2-1: Information Delivery Using PBCH Payload

Among the RRM-RSs, the SS / PBCH block may be used for time-frequency synchronization, and thus is generally considered as a basic signal for RRM. In particular, since the SS / PBCH block for RRM measurement is transmitted within the SMTC window set by the base station, and the signal transmission through the SMTC can give a high priority to the signal transmission through the LBT, It may be advantageous in conveying statistical information on the LBT operation as described above or information on the transmission counter.

In particular, when transmitting a transmission counter for an SS / PBCH block, information on the transmission counter can be obtained through the PBCH at the time of performing an RRM measurement using the SS / PBCH block. It may be suitable for passing a transmission counter for a / PBCH block. However, delivering the statistical information and / or the transmission counter through the PBCH payload has a disadvantage in that decoding of the PBCH should always be performed in the process of performing the RRM measurement.

2) Embodiment 2-2: Define a signal using a sequence in an SMTC window

According to the embodiment 2-1, when information is transmitted using a PBCH payload, PBCH decoding must be performed every time. Accordingly, a separate signal for transmitting the statistical information and / or the transmission count may be defined in the SMTC window. In addition, the signal may be defined as a signal using a sequence such as CSI-RS or DM-RS in order to avoid the problem of increasing decoding complexity as in the case of PBCH.

At this time, the terminal detects statistical information related to the LBT operation or a transmission counter through correlation for a plurality of sequences.

Since the embodiment 2-2 configures a signal by using a sequence, if a channel for transmitting system information such as RMSI (Remaining Minimum System Information) or OSI (Other System Information) is defined within the SMTC window, the RMSI or OSI is defined. The system overhead can be reduced by using a DM-RS such as a PDCCH or a PDSCH for a signal for transmitting the statistical information and / or the transmission counter of the embodiment 2-2. Meanwhile, in the case of the embodiment 2-2, when the UE receives the PDCCH or PDSCH, it is necessary to perform blind detection for the DM-RS.

3) Example 2-3: Transfer of Statistical Information and / or Transmission Counter for LBT Operation Using DCI

When the base station transmits information related to the transmission counter to the terminal, the base station may transmit information related to the transmission counter through a DCI necessary for transmitting PDSCH resource information during downlink burst transmission. For example, when the RMSI is always transmitted in the SMTC window, the transmission counter information for the SS / PBCH block may be transmitted through the DCI for the RMSI. In addition, when transmitting the success of the transmission by the LBT for the downlink burst using a transmission counter (transmission counter) can be transmitted through the DCI associated with the downlink burst transmission.

In other words, when LBT related parameters are applied differently for each channel, counter information may be transmitted for each channel. Therefore, the terminal may define statistical information and / or transmission counter for separate LBT operation for each RNTI, and the base station may transmit statistical information and / or transmission counter for LBT operation for each RNTI.

In addition, the information related to the RRM-RS transmission delay (or transmission success) probability by the LBT may be quantized and transmitted through the DCI. In addition, when transmitting the RRM-RS transmission delay (or transmission success) probability by LBT for the entire cell, broadcast or multicast group common PDCCH (group-common PDCCH) may be used.

Example 3: LBT Transfer counter for the action  Information and LBT  Terminal operation using statistical information about the operation

As described above, the terminal may perform the following operations using transmission counter information for the LBT operation or statistical information for the LBT operation.

1) Example 3-1: Correction to L3 Filtering Value

As described above, the UE determines by itself whether the RRM-RS transmission is delayed by the LBT, and determines whether to perform filtering in a higher layer by using the information determined by the LBT. However, if it is recognized that the RRM-RS transmission delay is incorrectly determined through the information on the transmission counter, the UE has already filtered using the information on the corresponding transmission counter and the previously measured signal size and quality information. It is possible to carry out correction on the collected information.

In addition, the terminal may report the value measured at the time when transmission is determined to the upper layer through the information on the transmission counter, and may perform filtering in the higher layer based on this. In this case, when one or more transmission counters are increased, information determined to be valid among the previously measured information about the signal size and quality may be collected and transmitted to the upper layer.

2) Embodiment 3-2: Cell redirection or frequency redirection based on the probability of RRM-RS transmission delay (or RRM-RS transmission success) by LBT

It can be assumed that the probability of the RRM-RS transmission delay (or transmission success) by the LBT transmitted by the base station to the terminal is determined based on the traffic load of another operator network or another RAT around the base station. have. In this case, even though the quality of the signal received from the serving base station is good, the terminal may not be provided with a good quality service (eg, data throughput or latency) from the serving base station.

In such a state, it may not be advantageous for the terminal to continuously access the serving base station in terms of service maintenance, and even if the quality of the signal transmitted from the base station is slightly low, it may be advantageous to move to another cell or another frequency band to receive the service. .

Therefore, the UE may determine cell redirection or frequency redirection based on the probability of RRM-RS transmission delay (or transmission success) by LBT for each cell or frequency band. In this case, the terminal may directly calculate the RRM-RS transmission delay probability by the LBT for each cell or frequency band using a transmission counter value.

For example, the terminal may determine cell redirection or frequency redirection based on a predetermined threshold. In addition, when the probability of RRM-RS transmission delay for a specific cell or a specific frequency band is high, a redirection probability for a specific cell or a specific frequency band is defined as a high state, and based on this, whether to reset the cell or frequency Can be determined. Specifically, random number generation between [0,1] is performed, and the cell or frequency redirection is compared by comparing the generated value with the redirection probability for a specific cell or a specific frequency band. It can be determined. Meanwhile, as described above, the UE may determine whether to delay the transmission of the RRM-RS based on the RRM-RS transmission delay probability and directly determine whether to reset the cell or the frequency. It may also forward to, so that the base station determines whether to reset the cell or frequency. In this case, the RRM-RS transmission delay probability may be information related to the RRM-RS transmission transmitted by the base station, or may be information determined by the UE itself about the RRM-RS transmission delay and / or the RRM-RS transmission delay probability.

In addition, the redirection probability for a specific cell or a specific frequency band according to the RRM-RS transmission delay (or success) probability by a threshold or LBT can be set by the base station, and the set probability is actually reset to a cell or frequency ( Whether to use for redirection) can be informed to the terminal.

In addition, if the cell to be reset or a cell present at the frequency to be reset transmits the same transmission counter or statistical information about the LBT operation as the serving cell, the cell to be reset or to the frequency to be reset is The transmission delay probability of the existing cell is smaller than the transmission delay probability of the serving cell by a predetermined value or more so that the terminal can finally determine whether to reset.

3) Example 3-3: Determining Whether to Send a Measurement Report to a Neighbor Cell

The NR system measures the signal size and quality of a neighbor cell and satisfies a specific condition, when the UE meets a specific condition, through a measurement report (MR), the signal size of the serving cell, neighbor cell and / or cells of other frequency bands and Report the quality information to the base station, the base station instructs the terminal handover (handover) to a specific target cell based on the received measurement report. In this case, the specific condition may be that the RSRP of the serving cell is measured below the threshold, or the RSRP of the neighboring cell is larger than the RSRP of the serving cell by more than the threshold.

On the other hand, since the base station selects a cell and frequency band based only on the size and quality of the signal, it does not reflect the traffic load from other carrier networks or other RATs occupied by the target cell, and thus, does not reflect traffic loads of other RATs in the unlicensed band. There is a problem in that the link between the base station and the terminal is maintained even though the base station cannot transmit a signal to the terminal due to channel occupation.

To solve this problem, the UE has a higher RRM-RS transmission delay probability due to LBT of a neighboring cell than a predetermined threshold, or if the RRM-RS transmission delay probability of a serving cell is greater than or equal to a threshold of RRM-RS transmission delay of a neighboring cell. In this case, the information on the signal size and quality for the corresponding cell may not be reported. At this time, an event such as a handover occurring from the signal size and quality of the corresponding cell may be ignored. In addition, the RRM-RS transmission delay probability may be calculated based on the transmission counter transmitted by the base station and / or statistical information on the LBT operation or by information determined by the terminal itself, and is a threshold value that does not perform the measurement report. Can be set by the base station.

On the other hand, when a corresponding event occurs and reports a signal size and quality thereof for the base station to control an event such as a handover, the UE transmits an RRM-RS transmission delay (or success) by the LBT of the corresponding cell to the base station. It is also possible to report the probability by including it in the measurement report. The base station may determine which cell to handover or do not perform the handover by reflecting the traffic load from the reported RRM-RS transmission delay probability by the LBT.

18 illustrates an embodiment of a wireless communication device according to an embodiment of the present invention.

The wireless communication device described with reference to FIG. 18 may represent a terminal and / or a base station according to an embodiment of the present invention. However, the wireless communication device of FIG. 18 is not necessarily limited to a terminal and / or a base station according to the present embodiment, and may be replaced with various devices such as a vehicle communication system or device, a wearable device, a laptop, a smart phone, and the like. Can be. More specifically, the apparatus includes a base station, a network node, a transmitting terminal, a receiving terminal, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, an unmanned aerial vehicle (UAV), and artificial intelligence (AI). Modules, Robots, Augmented Reality Devices, Virtual Reality Devices, MTC Devices, IoT Devices, Medical Devices, Fintech Devices (or Financial Devices), Security Devices, Climate / Environmental Devices or Other Fourth Industrial Revolution Sector or device associated with a 5G service. For example, a drone may be a vehicle in which humans fly by radio control signals. For example, the MTC device and the IoT device are devices that do not require human intervention or manipulation, and may be smart meters, bending machines, thermometers, smart bulbs, door locks, various sensors, and the like. For example, a medical device is a device used to examine, replace, or modify a device, structure, or function used for diagnosing, treating, alleviating, treating, or preventing a disease, such as a medical device, a surgical device, ( In vitro) diagnostic devices, hearing aids, surgical devices, and the like. For example, the security device is a device installed to prevent a risk that may occur and maintain safety, and may be a camera, a CCTV, a black box, or the like. For example, the fintech device is a device that can provide financial services such as mobile payment, and may be a payment device or a point of sales (POS). For example, the climate / environmental device may mean a device for monitoring and predicting the climate / environment.

In addition, the transmitting terminal and the receiving terminal are mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants, portable multimedia players, navigation, slate PCs. , Tablet PCs, ultrabooks, wearable devices, such as smartwatches, glass glasses, head mounted displays, and foldables foldable) devices and the like. For example, the HMD is a display device of a type worn on the head and may be used to implement VR or AR.

18, a terminal and / or a base station according to an embodiment of the present invention may include at least one processor 10, a transceiver 35, such as a digital signal processor (DSP) or a microprocessor, Power management module 5, antenna 40, battery 55, display 15, keypad 20, memory 30, subscriber identity module (SIM) card 25, speaker 45 and microphone ( 50) and the like. In addition, the terminal and / or the base station may include a single antenna or multiple antennas. Meanwhile, the transceiver 35 may also be referred to as a radio frequency module (RF module).

Processor 10 may be configured to implement the functions, procedures, and / or methods described in FIGS. In at least some of the embodiments described in FIGS. 1 through 17, the processor 10 may implement one or more protocols, such as layers of a wireless interface protocol (eg, functional layers).

The memory 30 is connected to the processor 10 and stores information related to the operation of the processor 10. The memory 30 may be located inside or outside the processor 10 and may be connected to the processor through various technologies such as wired or wireless communication.

The user may enter various types of information (eg, indication information such as a telephone number) by various techniques such as pressing a button on the keypad 20 or voice activation using the microphone 50. The processor 10 performs appropriate functions such as receiving and / or processing the user's information and dialing the telephone number.

It is also possible to retrieve data (eg, operation data) from the SIM card 25 or the memory 30 to perform the appropriate functions. In addition, the processor 10 may receive and process GPS information from a GPS chip to obtain location information of a terminal and / or a base station such as a vehicle navigation and a map service, or perform a function related to the location information. In addition, the processor 10 may display these various types of information and data on the display 15 for the user's reference and convenience.

The transceiver 35 is connected to the processor 10 to transmit and / or receive a radio signal such as a radio frequency (RF) signal. In this case, the processor 10 may control the transceiver 35 to initiate communication and transmit a radio signal including various types of information or data such as voice communication data. Transceiver 35 may include a receiver for receiving wireless signals and a transmitter for transmitting. Antenna 40 facilitates the transmission and reception of wireless signals. In some embodiments, upon receiving a wireless signal, the transceiver 35 may forward and convert the signal to a baseband frequency for processing by the processor 10. The processed signal may be processed according to various techniques, such as being converted into audible or readable information, and such a signal may be output through the speaker 45.

In some embodiments, the sensor may also be connected to the processor 10. The sensor may include one or more sensing devices configured to detect various types of information including speed, acceleration, light, vibration, and the like. The processor 10 receives and processes sensor information obtained from a sensor such as proximity, location, and image, thereby performing various functions such as collision avoidance and autonomous driving.

Meanwhile, various components such as a camera and a USB port may be additionally included in the terminal and / or the base station. For example, a camera may be further connected to the processor 10, and such a camera may be used for various services such as autonomous driving, vehicle safety service, and the like.

As such, FIG. 18 is only an embodiment of devices configuring a terminal and / or a base station, but is not limited thereto. For example, some components, such as keypad 20, global positioning system (GPS) chip, sensor, speaker 45, and / or microphone 50 may be excluded for terminal and / or base station implementation in some embodiments. It may be.

Specifically, to implement the embodiments of the present invention, the operation of the wireless communication device illustrated in FIG. 18 is a terminal according to an embodiment of the present invention. When the wireless communication device is a terminal according to an exemplary embodiment of the present disclosure, the processor 10 controls the transceiver 35 to receive information related to RRM-RS transmission. At this time, the information related to the RRM-RS transmission may be defined according to the first embodiment. In addition, the signal or channel used to transmit and receive information related to the RRM-RS transmission, according to the second embodiment, the sequence within the PBCH (Physical Broadcast Channel) payload, SMTC (SS / PBCH Block Measurement Time Configuration) window Based signal and / or downlink control information (DCI) may be utilized.

Upon receiving the information related to the RRM-RS transmission, the processor 10 performs a specific operation for at least one of the embodiments described in the third embodiment based on the third embodiment by using the information related to the RRM-RS transmission. Can be done.

Meanwhile, in order to implement the embodiments of the present disclosure, when the wireless communication apparatus illustrated in FIG. 18 is a base station according to an embodiment of the present disclosure, the processor 10 may transmit information related to RRM-RS transmission to a terminal. The transceiver 35 may be controlled. In this case, information related to RRM-RS transmission may be defined according to the first embodiment (S1601). In addition, the processor 10 may transmit and receive information related to the RRM-RS using a signal or a channel according to the second embodiment.

In addition, the processor 10 may control the transceiver 35 to receive a report on the result value measured using the RRM-RS from the terminal. However, the process of reporting the measurement result is not always performed, and may be limited to the case where the UE determines to transmit the measurement report for the neighbor cell based on the third embodiment. In addition, the processor 10 may perform necessary operations according to the third embodiment in addition to receiving a measurement result using the RRM-RS. For example, according to the third embodiment, the terminal may be controlled to perform an operation such as handover or frequency redirection.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

Certain operations described in this document as being performed by a base station may in some cases be performed by an upper node thereof. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The radio resource measuring method and apparatus for the same in the unlicensed band have been described based on the example applied to the fifth generation NewRAT system, but it is possible to apply to various wireless communication systems in addition to the fifth generation NewRAT system.

Claims (15)

1. In the method for the terminal redirection (serving) in the unlicensed band,

   Receive information related to RRM-RS (Radio Resource Measurement-Reference Signal) transmission probability by LBT (Listen before Talk) in each of a plurality of cells,

   Obtaining whether or not to redirect the serving cell based on the information;

   Resetting a serving cell based on the obtained reset or not;

   How to reset serving cell.
2. The method of claim 1,

   The information is a transmission counter value relating to the number of times the RRM-RS has been successfully transmitted.

   The RRM-RS transmission probability is calculated based on the transmission counter value received for a predetermined time.

   How to reset serving cell.
3. The method of claim 1,

   When the RRM-RS transmission probability is greater than or equal to a certain threshold, a serving cell is reset.

   How to reset serving cell.
4. The method of claim 1,

   Resetting the one cell to the serving cell when the RRM-RS transmission probability of any one cell among the plurality of cells is smaller than a predetermined RRM-RS transmission probability of the serving cell,

   How to reset serving cell.
5. The method of claim 4, wherein

   The signal quality of the serving cell is higher than the signal quality of any one cell,

   How to reset serving cell.
6. The method of claim 1,

   The information may be a transmission success probability of RRM-RS or transmission failure probability of RRM-RS in downlink burst which is a total downlink transmission opportunity by LBT for a predetermined time.

   How to reset serving cell.
7. The method of claim 1,

   The terminal is capable of communicating with at least one of a terminal, a network, a base station, and an autonomous vehicle other than the terminal,

   How to reset serving cell.
8. An apparatus for resetting a serving cell in an unlicensed band,

   Memory; And

   At least one processor coupled with the memory;

   The at least one processor,

   Receive information related to RRM-RS (Radio Resource Measurement-Reference Signal) transmission probability by LBT (Listen before Talk) in each of a plurality of cells,

   Obtaining whether or not to redirect the serving cell based on the information;

   Resetting a serving cell based on the obtained reset or not;

   Device.
9. The method of claim 8,

   The information is a transmission counter value relating to the number of times the RRM-RS has been successfully transmitted.

   The RRM-RS transmission probability is calculated based on the transmission counter value received for a predetermined time.

   Device.
10. The method of claim 8,

    When the RRM-RS transmission probability is greater than or equal to a certain threshold, a serving cell is reset.

    Device.
11. The method of claim 8,

    Resetting the one cell to the serving cell when the RRM-RS transmission probability of any one cell among the plurality of cells is smaller than a predetermined RRM-RS transmission probability of the serving cell,

    Device.
12. The method of claim 11,

    The signal quality of the serving cell is higher than the signal quality of any one cell,

    Device.
13. The method of claim 8,

    The information may be a transmission success probability of RRM-RS or transmission failure probability of RRM-RS in downlink burst which is a total downlink transmission opportunity by LBT for a predetermined time.

    Device.
14. The method of claim 8,

    The device may be capable of communicating with at least one of a terminal, a network, a base station, and an autonomous vehicle other than the device.

    Device.
15. A terminal for resetting a serving cell in an unlicensed band,

    Transceiver; And

    At least one processor coupled with the transceiver;

    The at least one processor,

    The transceiver is controlled to receive information related to RRM-RS (Radio Resource Measurement-Reference Signal) transmission probability by LBT (Listen before Talk) in each of a plurality of cells,

    Obtaining whether or not to redirect the serving cell based on the information;

    Resetting a serving cell based on the obtained reset or not;

    Terminal.

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