KR20200103234A - Methods for controlling a Secondary Cell Group and Apparatuses thereof - Google Patents

Abstract

The present invention relates to a control method and apparatus for providing rapid use of a Secondary Cell Group (SCG) configured by a UE through multi-rat dual connectivity (MR-DC) in a next-generation radio access network (NR). An embodiment is a method for a terminal to perform fast SCG use, including configuring a PSCell in a specific state and using a fast SCG using a PSCell, wherein the PSCell is a specific method that is distinguished from an active state and an inactive state. It provides a method and apparatus, characterized in that the state.

Description

SCG control method and apparatus TECHNICAL FIELD [Methods for controlling a Secondary Cell Group and Apparatuses thereof]

The present invention relates to a control method and apparatus for providing rapid use of a Secondary Cell Group (SCG) configured by a UE through multi-rat dual connectivity (MR-DC) in a next-generation radio access network (NR).

An embodiment is a method for a terminal to perform fast SCG use, including configuring a PSCell in a specific state and using a fast SCG using a PSCell, wherein the PSCell is a specific method that is distinguished from an active state and an inactive state. It provides a method and apparatus, characterized in that the state.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.
5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is an Example of symbol level alignment among different SCS
9 is a diagram showing a configuration of a base station according to another embodiment.
10 is a diagram showing a configuration of a user terminal according to another embodiment.

Hereinafter, some embodiments of the present technical idea will be described in detail with reference to exemplary drawings. In adding reference numerals to elements of each drawing, the same elements may have the same numerals as possible even if they are indicated on different drawings. In addition, in describing the technical idea, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the technical idea, the detailed description may be omitted.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present embodiments. These terms are only for distinguishing the component from other components, and the nature, order, order, or number of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected or connected to that other component, but other components between each component It is to be understood that is "interposed", or that each component may be "connected", "coupled" or "connected" through other components.

In addition, terms and technical names used in the present specification are for describing specific embodiments, and the technical idea is not limited thereto. The terms described below may be interpreted as meanings generally understood by those of ordinary skill in the technical field to which the present technical idea belongs unless otherwise defined. When the corresponding term is an incorrect technical term that does not accurately express the present technical idea, it will be replaced with a technical term that can be correctly understood by those skilled in the art to be understood. In addition, general terms used in the present specification should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted as an excessively reduced meaning.

The wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, and a core network.

The embodiments disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA). It can be applied to various wireless access technologies such as. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented using a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), and the like. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) using evolved-UMTSterrestrial radio access (E-UTRA), and employs OFDMA in downlink and SC- in uplink. Adopt FDMA. As described above, the present embodiments may be applied to a wireless access technology currently disclosed or commercialized, and may be applied to a wireless access technology currently being developed or to be developed in the future.

Meanwhile, a terminal in the present specification is a generic concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system, and is a UE in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio). In addition to (User Equipment), it should be interpreted as a concept that includes all of MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in GSM. In addition, the terminal may be a user's portable device such as a smart phone according to the usage type, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal or an M2M terminal equipped with a communication module so that machine type communication is performed.

The base station or cell of the present specification refers to the end of communication with the terminal in terms of the network, and Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmit Point, Receiving Point, Transmitting Point), Relay Node ), a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell.

In the various cells listed above, since there is a base station controlling each cell, the base station can be interpreted in two meanings. 1) In relation to the radio area, the device itself may provide a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, and a small cell, or 2) the radio area itself may be indicated. In 1), all devices that are controlled by the same entity that provide a predetermined wireless area are controlled by the same entity, or all devices that interact to form a wireless area in collaboration are instructed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. may be an embodiment of a base station according to the configuration method of the wireless area. In 2), it is possible to instruct the base station to the radio region itself that receives or transmits a signal from the viewpoint of the user terminal or the viewpoint of a neighboring base station.

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

Uplink (Uplink, UL, or uplink) refers to a method of transmitting and receiving data to a base station by a UE, and downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data to a UE by a base station. The downlink may refer to a communication or communication path from multiple transmission/reception points to the terminal, and the uplink may refer to a communication or communication path from the terminal to multiple transmission/reception points. In this case, in the downlink, the transmitter may be a part of the multiple transmission/reception points, and the receiver may be a part of the terminal. In addition, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multiple transmission/reception points.

Uplink and downlink transmit and receive control information through a control channel such as Physical Downlink Control CHannel (PDCCH), Physical Uplink Control CHannel (PUCCH), etc., and physical downlink shared channel (PDSCH), physical uplink shared channel (PUSCH), etc. The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is expressed in the form of'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

In order to clarify the description, hereinafter, the present technical idea is mainly described with respect to a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical feature is not limited thereto.

After research on 4G (4th-Generation) communication technology, 3GPP is conducting research on 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP is conducting research on LTE-A pro, which has improved LTE-Advanced technology as a 5G communication technology in accordance with the requirements of ITU-R, and a new NR communication technology separate from 4G communication technology. It is expected that both LTE-A pro and NR will be submitted as 5G communication technology, but in the following, for convenience of explanation, these embodiments will be described focusing on NR.

The operation scenario in NR defined various operation scenarios by adding considerations to satellites, automobiles, and new verticals from the existing 4G LTE scenario.In terms of service, eMBB (Enhanced Mobile Broadband) scenario, high terminal density, but wide It is deployed in the range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, a low latency technology, a mmWave support technology, and a forward compatible provision technology are applied. In particular, in the NR system, various technical changes are proposed in terms of flexibility to provide forward compatibility. Main technical features will be described below with reference to the drawings.

<NR system general>

1 is a diagram schematically showing a structure of an NR system to which this embodiment can be applied.

1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN controls user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment). It is composed of gNB and ng-eNB that provide plane (RRC) protocol termination. The gNB or gNB and ng-eNB are interconnected through an Xn interface. The gNB and ng-eNB are each connected to 5GC through the NG interface. The 5GC may include an Access and Mobility Management Function (AMF) in charge of a control plane such as a terminal access and mobility control function, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6GHz (FR1, Frequency Range 1) and frequencies above 6GHz (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in the present specification should be understood in a sense encompassing gNB and ng-eNB, and may be used as a means to distinguish between gNB or ng-eNB as necessary.

<NR wave form, numer roller and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and has the advantage of being able to use a low complexity receiver with high frequency efficiency.

On the other hand, in NR, since the requirements for data rate, delay rate, and coverage are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

값이 2의 지수 값으로 사용되어 지수적으로 변경된다.Specifically, the NR transmission neuron is determined based on sub-carrier spacing and CP (Cyclic prefix), based on 15khz as shown in Table 1 below.

The value is used as an exponential value of 2 and changes exponentially.

Subcarrier spacing Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR numer rollers can be classified into 5 types according to the subcarrier interval. This is different from the fixed subcarrier spacing of 15khz of LTE, one of the 4G communication technologies. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120khz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 12, and 240khz. In addition, the extended CP is applied only to the 60khz subcarrier interval. Meanwhile, a frame structure in NR is defined as a frame having a length of 10 ms consisting of 10 subframes having the same length of 1 ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of the 15khz subcarrier interval, one subframe consists of 1 slot, and each slot consists of 14 OFDM symbols.

2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2, in the case of a normal CP, a slot is fixedly composed of 14 OFDM symbols, but the length of the slot may vary according to the subcarrier interval. For example, in the case of a newer roller having a 15khz subcarrier interval, a slot is 1ms long and has the same length as the subframe. In contrast, in the case of a newer roller with a 30khz subcarrier spacing, a slot consists of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, and the time length may vary according to the subcarrier interval.

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) in order to reduce the transmission delay of the radio section. If a wide subcarrier spacing is used, the length of one slot is shortened in inverse proportion, so that transmission delay in the radio section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario, and scheduling is possible in units of 2, 4, or 7 symbols.

In addition, unlike LTE, NR defines uplink and downlink resource allocation as a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot has been defined, and this slot structure is named and described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which a downlink symbol and an uplink symbol are combined are supported. In addition, NR supports that data transmission is distributed and scheduled in one or more slots. Accordingly, the base station may inform the UE of whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station can indicate the slot format by indicating the index of the table configured through RRC signaling specifically through the UE, using SFI, and dynamically indicate through Downlink Control Information (DCI) or statically or semi-statically through RRC. May be.

<NR physical resource>

Regarding the physical resource in NR, the antenna port, resource grid, resource element, resource block, bandwidth part, etc. are considered. Can be.

The antenna port is defined so that a channel carrying a symbol on an antenna port can be inferred from a channel carrying another symbol on the same antenna port. When the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or quasi co-location) relationship. Here, the wide-range characteristic includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, since the NR supports a plurality of neurons in the same carrier, a resource grid may exist according to each neuron in the resource grid. In addition, the resource grid may exist according to an antenna port, a subcarrier spacing, and a transmission direction.

A resource block consists of 12 subcarriers, and is defined only in the frequency domain. In addition, a resource element consists of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, NR defines “Point A” that serves as a common reference point for the resource block grid, a common resource block, and a virtual resource block.

4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.

In NR, unlike LTE where the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as shown in FIG. 4, the terminal can use the bandwidth part by designating the bandwidth part within the carrier bandwidth. In addition, the bandwidth part is associated with one neurology and is composed of a subset of consecutive common resource blocks, and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, in uplink and downlink, and data is transmitted and received using the active bandwidth part at a given time.

In the case of a paired spectrum, uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tuning between downlink and uplink operations is prevented. For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR initial connection>

In NR, the terminal accesses the base station and performs cell search and random access procedures to perform communication.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, obtains a physical layer cell ID, and obtains system information by using a synchronization signal block (SSB) transmitted by a base station.

5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.

Referring to FIG. 5, an SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

The terminal receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms time, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms period based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted under 3GHz, and up to 8 in a frequency band of 3 to 6GHz, and a maximum of 64 different beams in a frequency band of 6GHz or higher can be used to transmit SSBs.

Two SSBs are included in one slot, and the start symbol and the number of repetitions in the slot are determined according to the subcarrier interval as follows.

Meanwhile, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the conventional LTE SS. That is, the SSB may be transmitted even in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when broadband operation is supported. Accordingly, the UE monitors the SSB by using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are information on the center frequency of the channel for initial access, have been newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster to support fast SSB search of the terminal. I can.

The UE can acquire the MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the terminal to receive remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information about the location of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (e.g., SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neurology information is equally applied to messages 2 and 4 of the random access procedure for accessing the base station after the terminal completes the cell search procedure.

The aforementioned RMSI means SIB1 (System Information Block 1), and SIB1 is broadcast periodically (ex, 160 ms) in a cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it is necessary to receive newer roller information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling through the PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. SIBs other than SIB1 may be periodically transmitted or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH consisting of consecutive radio resources in a specific slot that is periodically repeated. In general, when a terminal initially accesses a cell, a contention-based random access procedure is performed, and when a random access is performed for beam failure recovery (BFR), a contention-free random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), a UL Grant (uplink radio resource), a temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and a TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for the random access preamble received by the base station. TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores a temporary C-RNTI. Also, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information for identifying the terminal should be included.

Finally, the terminal receives a downlink message for resolving contention.

<NR CORESET>

The downlink control channel in NR is transmitted in CORESET (Control Resource Set) having a length of 1 to 3 symbols, and transmits uplink/downlink scheduling information, SFI (Slot Format Index), and TPC (Transmit Power Control) information. .

In this way, NR introduced the concept of CORESET to secure system flexibility. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A QCL (Quasi CoLocation) assumption for each CORESET is set, and this is used to inform the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to 3 OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration so that additional configuration information and system information can be received from the network. After establishing the connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

In this specification, frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals, and various messages related to NR (New Radio) Can be interpreted as a meaning used in the past or present, or in various meanings used in the future.

New Radio (NR)

NR, which has been recently conducted in 3GPP, has been designed to satisfy various QoS requirements required for each detailed and detailed usage scenario as well as an improved data rate compared to LTE. In particular, eMBB (Enhancement Mobile BroadBand), mMTC (massive MTC), and URLLC (Ultra Reliable and Low Latency Communications) were defined as representative usage scenarios of NR. A structure design is being provided. Since each usage scenario has different requirements for data rates, latency, reliability, coverage, etc., it is a method to efficiently satisfy the requirements for each usage scenario through the frequency band constituting an arbitrary NR system. eg subcarrier spacing, subframe, TTI, etc.) based radio resource units (units) are designed to efficiently multiplex.

As one method for this, a method of multiplexing and supporting based on TDM, FDM, or TDM/FDM through one or more NR component carrier(s) for numerology having different subcarrier spacing values, and scheduling units in the time domain. In the configuration, a discussion was made on how to support more than one time unit. In this regard, in NR, a subframe was defined as a kind of time domain structure, and 14 OFDM symbols of normal CP overhead based on 15kHz SCS (Sub-Carrier Spacing), which is the same as LTE, as a reference numerology for defining the corresponding subframe duration. It was decided to define a single subframe duration composed of. Accordingly, in NR, the subframe has a time duration of 1 ms. However, unlike LTE, a subframe of NR is an absolute reference time duration, and slots and mini-slots may be defined as time units that are the basis of actual uplink/downlink data scheduling. In this case, the number and y values of OFDM symbols constituting the corresponding slot are determined to have a value of y=14 regardless of the SCS value in the case of normal CP.

Accordingly, a random slot consists of 14 symbols, and according to the transmission direction of the corresponding slot, all symbols are used for DL transmission, or all symbols are used for UL transmission, or DL portion + (gap) + It can be used in the form of a UL portion.

In addition, a mini-slot consisting of fewer symbols than the slot is defined in an arbitrary numerology (or SCS), and based on this, a short time-domain scheduling interval for uplink/downlink data transmission/reception is set, or slot aggregation A long time-domain scheduling interval for transmitting/receiving uplink/downlink data may be configured through. In particular, in the case of transmission and reception of latency critical data such as URLLC, it is difficult to satisfy the latency requirement when scheduling is performed in a slot unit based on 1ms (14 symbols) defined in a numerology-based frame structure with a small SCS value such as 15kHz. Because of this, it is possible to define a mini-slot consisting of fewer OFDM symbols than the corresponding slot, and based on this, to schedule for latency critical data such as the corresponding URLLC.

Alternatively, as described above, by multiplexing and supporting numerology having different SCS values in one NR Carrier in a TDM and/or FDM method, based on the slot (or mini-slot) length defined for each numerology. Scheduling data according to latency requirements is also being considered. For example, as shown in Figure 1 below, when the SCS is 60 kHz, the symbol length is reduced by about 1/4 compared to the SCS 15 kHz, so when one slot is configured with the same 14 OFDM symbols, the corresponding 15 kHz-based slot While the length becomes 1ms, the slot length based on 60kHz is reduced to about 0.25ms.

MR-DC

Multi-Radio Dual Connectivity (MR-DC) technology is an Intra E-UTRA Dual Connectivity (DC) that is configured to use resources provided by two different nodes connected by a non-ideal backhaul to multiple RX/TX terminals. ) Is a generalization. At this time, one node provides NR access and the other provides E-UTRA or NR access. MR-DC includes the following types.

-EN-DC: E-UTRA-NR Dual Connectivity

-NE-DC: NR-E-UTRA Dual Connectivity

-NGEN-DC: NG-RAN E-UTRA-NR Dual Connectivity

-NR-DC: NR-NR Dual Connectivity

In DC, a master cell group (MCG) of a master node (MN) and a secondary cell group (SCG) of a secondary node (SN) are configured for one terminal, and the PSCell, which is a primary cell within the SCG, is It is configured with PUCCH resources. Like the PCell, the PSCell is always activated when the cell is configured and cannot be deactivated.

DC technology has the effect of boosting the data rate to the terminal by adding SN in addition to the MN. However, DC technology required a long time to add and use SCG, and it was not optimized in terms of power consumption. For example, the time taken to configure the SCG PSCell in the terminal is T _{config_PSCell} When is, it is calculated as follows.

+ TPSCell_ DU + 2 ms, Tconfig_PSCell = TRRC_delay + Tprocessing + Tsearch +

+ TPSCell_ DU + 2 ms,

Here, each time variable is defined as follows.

TRRC_delay is the RRC procedure delay..

Tprocessing is the SW processing time needed by UE, including RF warm up period. Tprocessing = 20 ms if NR PSCell is in FR1, Tprocessing = 40 ms if NR PSCell is in FR2.

Tsearch is the time for AGC settling and PSS/SSS detection.

- For NR PSCell in FR1: if the target cell is known, then Tsearch = 0 ms. If the target cell is an unknown intra-frequency cell and signal quality is sufficient for successful cell detection on the first attempt, then Tsearch = SMTC periodicity + 5 ms. If the target cell is an unknown inter-frequency cell and signal quality is sufficient for successful cell detection on the first attempt, then Tsearch = [TBD*SMTC periodicity + 5] ms;

- For NR PSCell in FR2: if the target cell is an unknown intra-frequency cell and signal quality is sufficient for successful cell detection on the first attempt, then Tsearch = [N1*SMTC periodicity + 5] ms. If the target cell is an unkown inter-frequency cell and signal quality is sufficient for successful cell detection on the first attempt, then Tsearch = [N1*TBD* SMTC periodicity + 5] ms, else Tsearch = [TBD* SMTC periodicity + 5 ] ms.

is time for fine time tracking and acquiring full timing information of the target cell.

= 1 SMTC periodicity ms.

is time for fine time tracking and acquiring full timing information of the target cell.

= 1 SMTC periodicity ms.

TPSCell_ DU is the delay uncertainty in acquiring the first available PRACH occasion in the NR PSCell. TPSCell_ DU is up to x*10 +10 ms. x is defined in the table 6.3.3.2-2 of 3GPP TS38.211.

Even if the PSCell belongs to FR1, it is known that a delay of about 80 ms is involved. In addition, an Xn/X2 signaling delay for receiving an SCG addition request and response to an SN may be added to the UE before adding the SCG, configuring the measurement for the SCG, reporting the measurement result. In addition, as data to be transmitted was irregularly generated, the utilization rate could drop as a delay was added when the SCG was released and the SCG was added again.

As described above, the conventional DC technology did not support fast SCG use and/or power consumption reduction. Accordingly, in the process of repeating SCG configuration and release in order to use SCG, there is a problem that the data processing utilization rate decreases due to delays for SCG measurement configuration, measurement result reporting, Xn/X2 signaling, PSCell configuration, and SCG release. there was.

The present invention conceived to solve the above problem is to provide an SCG control method and apparatus for a terminal to provide fast SCG use.

For convenience of explanation, the present invention will be described below based on NR. However, this is only for convenience of description, and the present invention may be applied to LTE or another radio access network, and this is also included in the scope of the present invention. Also, the present invention can be applied to any type of MR-DC. Some information elements described in the present invention include information elements specified in TS 38.331, which is an RRC standard or TS 38.321, which is a MAC standard. Even if the contents of the terminal operation related to the definition of the corresponding information element are not included in the specification, the contents may be included in the present invention or used as a claim. Hereinafter, a method of minimizing the power consumption of the terminal while reducing the configuration delay for the SCG, and quickly utilizing the SCG will be described. It is also within the scope of the present invention to combine each method described individually or through any combination.

Supports fast SCG use by defining a new state that is distinct from the activation/deactivation state for the PSCell.

In order to continuously utilize the SCG, data must be transmitted through the SCG whenever data occurs without releasing the added SCG in the RRC connection state. Since the current PSCell always supports only the active state, the power consumption of the terminal increases when the SCG is configured. Since data traffic may occur intermittently, in order to minimize power consumption, it is necessary to release it and configure the SCG to transmit data when data is generated. However, as described above, a significant delay is required to configure the SCG. In order to minimize the power consumption of the terminal and use the fast SCG, even when there is no data transmission, the SCG/PSCell is transferred to a state that is distinct from the active state without releasing it, and when data occurs, the data is quickly transferred to the active state. You can send and receive. For convenience of explanation, hereinafter, the activated state is denoted as a first state, and a new state distinguished from the activated/deactivated state is denoted as a second state. This is only for convenience of description, and may be replaced with an arbitrary name. For example, for SCG/SCG cells/PSCell, the second state distinguished from the activated/deactivated state may be replaced with an arbitrary name such as a standby state/suspend state/sleep state/sleep state.

For convenience of explanation, a method of defining a second state for a PSCell will be described below. This is for convenience of description and may be applied to the SCG or any cell in the SCG, and this is also included in the scope of the present invention.

For example, when the PSCell transitions to the second state, the terminal may support channel state reporting for the PSCell so that fast scheduling by the base station when data is generated later. For example, it reports the channel status (CSI) on the PSCell.

As another example, when the PSCell transitions to the second state, one or more of the following operations may be performed.

-SRS is not transmitted on the PSCell.

-Do not transmit on the UL-SCH on the PSCell.

-Do not transmit on RACH on the PSCell.

-PDCCH is not monitored on the PSCell.

As another example, when the PSCell transitions to the second state, one or more of the following operations may be performed.

-Can perform transmission on the RACH on the PSCell.

-SR is configured on the PSCell and can transmit SR.

-On the PSCell, a PDCCH monitoring period that is distinct from the activation state is configured so that the PDCCH can be monitored.

Configure a new state for PSCell that is differentiated from the enabled/disabled state through additional instruction information

When the PSCell transitions to the second state, the terminal may support channel state reporting for the PSCell to enable fast scheduling by the base station when data is generated later.

For example, when the PSCell transitions to the second state, a channel state report for the PSCell may be transmitted through the PSCell. Configuration information for this may be indicated to the terminal. The configuration information may be included in the CSI measurement configuration (csi-measconfig) included in the serving cell configuration (ServingCellConfig) for the PSCell and used, or a CSI measurement configuration specialized for the second state may be added and used. Alternatively, the terminal may include information for indicating to the base station to support the second state for the PSCell in the terminal capability information and transmit the information to the base station. The base station may transmit to the terminal including information for indicating the second state for the PSCell to the terminal. Alternatively, the CSI report configuration information (CSI-ReportConfig) indicated to the terminal may be used together with the CSI report configuration information of the first state, or may be used by adding a CSI report configuration specialized for the second state. Information for indicating this may be added. Alternatively, the CSI report configuration identification information (CSI-ReportConfigId) in the second state may be configured through information elements different from the CSI report configuration identification information in the first state, or may be configured with different values for the same information element. Alternatively, a PUCCH CSI resource (PUCCH-CSI-Resource: uplink BWP ID, pucch-resource) for CSI reporting in the second state may be configured. The PUCCH CSI resource for CSI reporting may be used with the PUCCH CSI resource configuration information of the first state, or may be used by adding a PUCCH CSI resource specialized for the second state. Information for indicating this may be added.

For another example, when the PSCell transitions to the second state, a channel state reporting for the PSCell may be transmitted to the SN through the MN. Channel state reporting for the PSCell between the UE and the MN may be transmitted through the PUCCH, and configuration information for this may be indicated to the UE. The channel state reporting for the PSCell between the UE and the MN may be transmitted through MAC CE or RRC signaling, and configuration information for this may be indicated to the UE.

For another example, when the PSCell transitions to the second state, other SCells in the SCG may transition to one of the second state, the inactive state, or the doment state. The doment state is one of the states of the LTE SCell, and the MAC entity (terminal) operates as follows.

-SRS is not transmitted on the SCell.

-Report CQI/PMI/RI/PTI/CRI for the SCell.

-Do not transmit on the UL-SCH on the SCell.

-Do not transmit on the RACH on the SCell.

-Do not monitor the PDCCH on the SCell.

-Do not transmit PUCCH on the SCell.

For another example, the SN may transition the PSCell from the first state to the second state by RRC signaling, MAC CE, or a timer instructed to the terminal.

For another example, when the PSCell transitions from the first state to the second state, the SN may transmit it to the MN.

For another example, when the PSCell transitions from the second state to the first state, the SN may transmit it to the MN.

For another example, the SN node may transmit the SN modification request to the MN, including instruction information, in order to transition the PSCell to the second state. The MN may indicate this to the terminal.

When transitioning to the first state, the SN can transfer it to the MN.

As another example, the aforementioned MAC CE may use one LCID that is distinguished from the activation/deactivation MAC or activation/domain MAC CE.

As described above, the present invention has the effect of allowing the SCG to be used quickly while reducing power consumption of the terminal.

9 is a diagram showing a configuration of a base station 1000 according to another embodiment.

Referring to FIG. 9, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The controller 1010 controls the overall operation of the base station 1000 according to controlling the terminal required to perform the above-described present invention to enable fast SCG use.

The transmission unit 1020 and the reception unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal.

10 is a diagram showing the configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 10, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiver 1110 receives downlink control information, data, and a message from the base station through a corresponding channel.

In addition, the controller 1120 controls the overall operation of the user terminal 1100 according to controlling the terminal required to perform the above-described present invention to enable fast SCG use.

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

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP and 3GPP2 wireless access systems. That is, steps, configurations, and parts not described in order to clearly reveal the present technical idea among the embodiments may be supported by the aforementioned standard documents. In addition, all terms disclosed in the present specification can be described by the standard documents disclosed above.

The above-described embodiments can be implemented through various means. For example, the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.

In the case of implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), and FPGAs. (Field Programmable Gate Arrays), can be implemented by a processor, a controller, a microcontroller, a microprocessor.

In the case of implementation by firmware or software, the method according to the embodiments may be implemented in the form of an apparatus, procedure, or function 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 through various known means.

In addition, terms such as "system", "processor", "controller", "component", "module", "interface", "model", and "unit" described above are generally It can mean a combination, software, or running software. For example, the above-described components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, an execution thread, a program, and/or a computer. For example, components can be both a controller or processor and an application running on a controller or processor. One or more components can reside within a process and/or thread of execution, and components can reside on one machine or be deployed on more than one machine.

The description above and the accompanying drawings are merely illustrative of the spirit of the present technology, and those of ordinary skill in the art can combine, separate, replace, and use configurations within the scope not departing from the essential characteristics of the present technology. Various modifications and variations such as changes will be possible. Accordingly, the embodiments disclosed in the present specification are not intended to limit the present technical idea, but to describe it, and the scope of the present technical idea is not limited by these embodiments. The scope of protection of the present technical idea should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present specification.

Claims (1)

In the method for the UE to perform fast SCG use,
Configuring the PSCell to a specific state; And
And using a fast SCG using the PSCell, wherein the PSCell is in a specific state distinguished from an activated state and an inactive state.

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