KR20210041945A - Method and apparatus for enhancing handover in a next generation mobile communication system - Google Patents

Abstract

The present invention relates to a communication technique that converges a 5G communication system with an IoT technology to support higher data rates after a 4G system and a system thereof. The present invention can be applied to intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on a 5G communication technology and an IoT-related technology. In addition, the present invention relates to an improved handover method.

Description

Improvement method and device for handover in next-generation mobile communication system {METHOD AND APPARATUS FOR ENHANCING HANDOVER IN A NEXT GENERATION MOBILE COMMUNICATION SYSTEM}

The present invention relates to a handover operation of a terminal in a mobile communication system. In addition, the present invention relates to signaling regarding handover between a terminal and a source base station and a target base station. Further, the present invention relates to a method and apparatus for improving measurement control for handover.

Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems. For this reason, a 5G communication system or a pre-5G communication system is called a Beyond 4G Network communication system or an LTE system and a Post LTE system. In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Giga (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, 5G communication systems include beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO). ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, in order to improve the network of the system, in 5G communication system, evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed. In addition, in 5G systems, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and SWSC (Sliding Window Superposition Coding), advanced access technologies such as Filter Bank Multi Carrier (FBMC), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

Meanwhile, the Internet is evolving from a human-centered connection network in which humans create and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, etc., is also emerging. In order to implement IoT, technological elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (information technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antenna, which are 5G communication technologies. will be. The application of a cloud radio access network (cloud RAN) as the big data processing technology described above can be said as an example of the convergence of 5G technology and IoT technology.

The technical problem to be achieved in an embodiment of the present invention is to provide an improved handover method. In addition, the technical problem to be achieved in the embodiment of the present invention is in the DAPS (dual active protocol stack) handover, which is a handover that does not disconnect the terminal connection with the source node until the connection with the target node is completed, It aims to provide a measurement setting method.

According to an embodiment of the present invention, when a terminal performs a handover, while continuing communication with the source cell until the process of establishing a connection with the target cell, a bandwidth part (BWP) is set in the source cell and the target cell required therefor, and uplink control It is possible to provide an operation of setting a channel, transmitting control signals for data transmission, and a method of setting a channel measurement operation for both cells.

According to an embodiment of the present invention, it is possible to provide an improved terminal handover method in a mobile communication system. In addition, according to an embodiment of the present invention, it is possible to provide improved signaling regarding handover between a terminal and a source base station and a target base station.

In addition, according to an embodiment of the present invention, through an improved method, the connection between the source cell and the target cell is maintained, measurement is performed, and data transmission/reception in two cells is possible by performing an operation through control and reference signal transmission. I can do it.

1 is a diagram illustrating a structure of an LTE system according to an embodiment of the present invention.
2 is a diagram illustrating a radio protocol structure of an LTE system according to an embodiment of the present invention.
3 is a diagram showing the structure of a next-generation mobile communication system according to an embodiment of the present invention.
4 is a diagram showing a radio protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.
5 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.
6 is a block diagram showing the configuration of a base station according to an embodiment of the present invention.
7 is a diagram illustrating a process of performing a general handover operation in a mobile communication system according to an embodiment of the present invention.
8A and 8B are diagrams illustrating a process of using a DAPS in a process of performing a handover according to an embodiment of the present invention.
9 is a diagram illustrating a process of performing a DAPS handover according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components in the accompanying drawings are indicated by the same reference numerals as possible. In addition, detailed descriptions of known functions and configurations that may obscure the subject matter of the present invention will be omitted.

In describing the embodiments herein, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly convey the gist of the present invention by omitting unnecessary description.

For the same reason, some elements in the accompanying drawings are exaggerated, omitted, or schematically illustrated. In addition, the size of each component does not fully reflect the actual size. The same reference numerals are assigned to the same or corresponding components in each drawing.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

At this time, it will be appreciated that each block of the flowchart diagrams and combinations of the flowchart diagrams may be executed by computer program instructions. Since these computer program instructions can be mounted on the processor of a general purpose computer, special purpose computer or other programmable data processing equipment, the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates a means to perform functions. These computer program instructions can also be stored in computer-usable or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement a function in a particular way, so that the computer-usable or computer-readable memory It is also possible for the instructions stored in the flow chart to produce an article of manufacture containing instruction means for performing the functions described in the flowchart block(s). Since computer program instructions can also be mounted on a computer or other programmable data processing equipment, a series of operating steps are performed on a computer or other programmable data processing equipment to create a computer-executable process to create a computer or other programmable data processing equipment. It is also possible for instructions to perform processing equipment to provide steps for executing the functions described in the flowchart block(s).

In addition, each block may represent a module, segment, or part of code that contains one or more executable instructions for executing the specified logical function(s). In addition, it should be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order depending on the corresponding function.

In this case, the term'~ unit' used in this embodiment refers to software or hardware components such as FPGA or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. Components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further separated into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card.

A term for identifying an access node used in the following description, a term for network entities, a term for messages, a term for an interface between network objects, a term for various identification information And the like are illustrated for convenience of description. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having an equivalent technical meaning may be used.

For convenience of description below, the present invention uses terms and names defined in the 3GPP 3rd Generation Partnership Project Long Term Evolution (LTE) standard. However, the present invention is not limited by the terms and names, and may be equally applied to systems conforming to other standards.

In various embodiments of the present invention, the MN may be interpreted as a master base station, and the SN may be interpreted as a secondary base station. In addition, in various embodiments of the present invention, the MN and the SN may be interpreted as different base stations and base stations using different radio access technologies (RATs), and in some cases, may be used as base stations using the same RAT. MN and SN may be classified using a general expression such as a first base station and a second base station.

In addition, in various embodiments of the present invention, the eNB and the gNB may be referred to as a base station, and may be classified using a general expression such as a first base station and a second base station in order to distinguish between the eNB and the gNB.

Compared to conventional handover, DAPS handover may have to perform different operations in terms of measurement configuration and channel state information (CSI) report. In the existing handover, a new measurement setting is applied at the time of receiving the HO command. In contrast, in DAPS, measurement must be performed and CSI report transmitted in both directions of the source base station and the target base station during a certain period of handover. To this end, a problem may arise when a new measurement setting is applied at the time of receiving an existing HO command. In various embodiments of the present invention, specific settings and operations for this will be described.

1 is a diagram illustrating a structure of an LTE system according to an embodiment of the present invention.

Referring to Figure 1, as shown in the radio access network of the LTE system is a next-generation base station (Evolved Node B, hereinafter ENB, Node B or base station) (1-05, 1-10, 1-15, 1-20) and It may be composed of a mobility management entity (Mobility Management Entity, MME) (1-25) and an S-GW (1-30, Serving-Gateway). User Equipment (hereinafter referred to as UE or UE) 1-35 may access an external network through ENBs 1-05 to 1-20 and S-GWs 1-30.

In FIG. 1, ENBs 1-05 to 1-20 may correspond to an existing node B of the UMTS system. The ENB is connected to the UE (1-35) through a radio channel and can perform a more complex role than the existing Node B. In the LTE system, all user traffic including real-time services such as VoIP (Voice over IP) through the Internet protocol can be serviced through a shared channel. Accordingly, there is a need for a device for scheduling by collecting state information such as a buffer state, an available transmission power state, and a channel state of the UEs, and the ENBs 1-05 to 1-20 may be in charge of this. One ENB can typically control multiple cells. For example, in order to implement a transmission rate of 100 Mbps, the LTE system may use orthogonal frequency division multiplexing (OFDM) in a 20 MHz bandwidth, for example, as a radio access technology. In addition, an adaptive modulation and coding (AMC) scheme for determining a modulation scheme and a channel coding rate according to the channel state of the terminal may be applied. The S-GW 1-30 is a device that provides a data bearer, and may create or remove a data bearer under the control of the MME 1-25. The MME 1-25 is a device responsible for various control functions as well as a mobility management function for the terminal 1-35, and may be connected to a plurality of base stations 1-05 to 1-20.

2 is a diagram showing a radio protocol structure of an LTE system according to an embodiment of the present invention.

Referring to Figure 2, the radio protocol of the LTE system is a packet data convergence protocol (Packet Data Convergence Protocol, PDCP) (2-05, 2-40), radio link control (Radio Link Control, RLC) in the terminal and the ENB, respectively. 2-10, 2-35), medium access control (MAC) (2-15, 2-30). PDCP (2-05, 2-40) may be in charge of operations such as IP header compression/restore. The main functions of PDCP (2-05, 2-40) can be summarized as follows.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

-Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM

-Retransmission of PDCP SDUs at handover and, for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure, for RLC AM

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard in uplink.

Radio Link Control (RLC) (2-10, 2-35) can perform an automatic repeat request (ARQ) operation by reconfiguring a PDCP packet data unit (PDU) to an appropriate size. . The main functions of RLC (2-10, 2-35) can be summarized as follows.

-Data transfer function (Transfer of upper layer PDUs)

-ARQ function (Error Correction through ARQ (only for AM data transfer))

-Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

-Re-segmentation of RLC data PDUs (only for AM data transfer)

-Reordering of RLC data PDUs (only for UM and AM data transfer)

-Duplicate detection (only for UM and AM data transfer)

-Error detection function (Protocol error detection (only for AM data transfer))

-RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

-RLC re-establishment

The MACs 2-15 and 2-30 are connected to several RLC layer devices configured in one terminal, and may perform an operation of multiplexing RLC PDUs to MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC (2-15, 2-30) can be summarized as follows.

-Mapping between logical channels and transport channels

-Multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels

-Scheduling information reporting

-Hybrid automatic repeat request (HARQ) function (Error correction through HARQ)

-Priority handling between logical channels of one UE

-Priority handling between UEs by means of dynamic scheduling

-MBMS service identification

-Transport format selection

-Padding function

The physical layer (2-20, 2-25) channel-codes and modulates upper layer data, converts it into OFDM symbols, and transmits it to the radio channel, or demodulates the OFDM symbol received through the radio channel, decodes the channel, and delivers it to the upper layer. You can do the action.

3 is a diagram showing the structure of a next-generation mobile communication system according to an embodiment of the present invention.

3, a radio access network of a next-generation mobile communication system (hereinafter referred to as NR or 2g) includes a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (3-10) and a next-generation radio core network (New Radio Core). Network, NR CN) (3-05). Next-generation radio user equipment (New Radio User Equipment, NR UE or terminal) 3-15 may access an external network through NR gNB 3-10 and NR CN 3-05.

In FIG. 3, the NR gNB 3-10 may correspond to an Evolved Node B (eNB) of an existing LTE system. The NR gNB 3-10 is connected to the NR UE 3-15 through a radio channel and can provide a service superior to that of the existing Node B. In a next-generation mobile communication system, all user traffic can be serviced through a shared channel. Accordingly, there is a need for an apparatus for scheduling by collecting state information such as a buffer state, an available transmit power state, and a channel state of the UEs, and the NR NB 3-10 may be in charge of this. One NR gNB can control multiple cells. In the next-generation mobile communication system, in order to implement ultra-high-speed data transmission compared to the current LTE, a bandwidth greater than or equal to the current maximum bandwidth may be applied. In addition, an orthogonal frequency division multiplexing (OFDM) technique may be used as a radio access technique, and an additional beamforming technique may be applied. In addition, an adaptive modulation and coding method (hereinafter referred to as AMC) for determining a modulation scheme and a channel coding rate according to a channel state of the terminal may be applied. The NR CN (3-05) may perform functions such as mobility support, bearer configuration, and quality of service (QoS) configuration. The NR CN (3-05) is a device responsible for various control functions as well as a mobility management function for a terminal, and may be connected to a plurality of base stations. In addition, the next-generation mobile communication system can be linked with the existing LTE system, and the NR CN (3-05) can be connected to the MME (3-25) through a network interface. The MME 3-25 may be connected to the eNB 3-30, which is an existing base station.

4 is a diagram showing a radio protocol structure of a next-generation mobile communication system according to an embodiment of the present invention.

Referring to FIG. 4, radio protocols of the next-generation mobile communication system include NR Service Data Adaptation Protocol (SDAP) (4-01, 4-45) and NR PDCP (4-05, respectively) in a terminal and an NR base station. 4-40), NR RLC (4-10, 4-35), NR MAC (4-15, 4-30).

The main functions of the NR SDAP (4-01, 4-45) may include some of the following functions.

- Transfer of user plane data

- Mapping between a QoS flow and a data radio bearer (DRB) for both DL and UL for uplink and downlink

- Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

- A function of mapping a relective QoS flow to a data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

For SDAP layer devices, the UE uses a radio resource control (RRC) message for each PDCP layer device, bearer or logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device. Can be set. When the SDAP header is set, the terminal includes a non-access layer (Non-Access Stratum, NAS) QoS (Quality of Service) reflection setting 1-bit indicator (NAS reflective QoS) and an access layer (Access Stratum, AS) QoS of the SDAP header. With the reflection configuration 1-bit indicator (AS reflective QoS), it is possible to instruct the UE to update or reconfigure mapping information for the uplink and downlink QoS flows and data bearers. The SDAP header may include QoS flow ID information indicating QoS. QoS information can be used as data processing priority, scheduling information, etc. to support smooth service.

The main functions of NR PDCP (4-05, 4-40) may include some of the following functions.

-Header compression and decompression (ROHC only)

-Transfer of user data

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-Order reordering function (PDCP PDU reordering for reception)

-Duplicate detection of lower layer SDUs

-Retransmission of PDCP SDUs

-Encryption and decryption function (Ciphering and deciphering)

-Timer-based SDU discard in uplink.

In the above description, the reordering function of the NR PDCP device may mean a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN). The reordering function of the NR PDCP device may include a function of transferring data to an upper layer in a rearranged order, or may include a function of directly delivering data without considering the order, and the order is rearranged and lost. It may include a function to record the lost PDCP PDUs, may include a function to report the status of the lost PDCP PDUs to the sender, and may include a function to request retransmission of the lost PDCP PDUs. have.

The main functions of the NR RLC (4-10, 4-35) may include some of the following functions.

-Data transfer function (Transfer of upper layer PDUs)

-In-sequence delivery of upper layer PDUs

-Out-of-sequence delivery of upper layer PDUs

-ARQ function (Error Correction through ARQ)

-Concatenation, segmentation and reassembly of RLC SDUs

-Re-segmentation of RLC data PDUs

-Reordering of RLC data PDUs

-Duplicate detection

-Protocol error detection

-RLC SDU discard function

-RLC re-establishment

In the above description, in-sequence delivery of the NR RLC device may mean a function of sequentially delivering RLC SDUs received from a lower layer to an upper layer. When one RLC SDU is originally divided into several RLC SDUs and received, the in-sequence delivery function of the NR RLC device may include a function of reassembling and delivering it.

In-sequence delivery of the NR RLC device may include a function of rearranging received RLC PDUs based on an RLC sequence number (SN) or a PDCP sequence number (SN). A function of recording lost RLC PDUs may be included, a function of transmitting a status report on lost RLC PDUs may be included, and a function of requesting retransmission of lost RLC PDUs may be included.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering only RLC SDUs up to before the lost RLC SDU to a higher layer when there is a lost RLC SDU.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering all RLC SDUs received before the timer starts to a higher layer if a predetermined timer expires even if there is a lost RLC SDU. have.

In-sequence delivery of the NR RLC device may include a function of sequentially delivering all RLC SDUs received so far to an upper layer if a predetermined timer expires even if there is a lost RLC SDU.

The NR RLC device may process RLC PDUs in an order of reception regardless of the sequence number (Out-of sequence delivery) and deliver them to the NR PDCP device.

When the NR RLC device receives a segment, it may receive segments stored in a buffer or to be received at a later time, reconfigure it into one complete RLC PDU, and then transmit it to the NR PDCP device.

The NR RLC layer may not include a concatenation function, and may perform a function in the NR MAC layer or may be replaced with a multiplexing function of the NR MAC layer.

In the above description, out-of-sequence delivery of the NR RLC device may mean a function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of an order. Out-of-sequence delivery of the NR RLC device may include a function of reassembling and delivering when one RLC SDU is originally divided into several RLC SDUs and received. Out-of-sequence delivery of the NR RLC device may include a function of storing RLC SNs or PDCP SNs of received RLC PDUs, arranging the order, and recording the lost RLC PDUs.

NR MAC (4-15, 4-30) can be connected to multiple NR RLC layer devices configured in one device, and the main functions of NR MAC (4-15, 4-30) include some of the following functions. can do.

-Mapping between logical channels and transport channels

-Multiplexing and demultiplexing function (Multiplexing/demultiplexing of MAC SDUs)

-Scheduling information reporting

-HARQ function (Error correction through HARQ)

-Priority handling between logical channels of one UE

-Priority handling between UEs by means of dynamic scheduling

-MBMS service identification

-Transport format selection

-Padding function

The NR PHY layer (4-20, 4-25) channel-codes and modulates upper layer data, converts it into OFDM symbols, and transmits it to the radio channel, or demodulates and channel-decodes OFDM symbols received through the radio channel to the upper layer. You can perform the transfer operation.

5 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present invention.

Referring to the drawing, the terminal includes a radio frequency (RF) processing unit 5-10, a baseband processing unit 5-20, a storage unit 5-30, and a control unit 5-40. I can. In addition, the control unit 5-40 may further include a multiple connection processing unit 5-42.

The RF processing unit 5-10 performs a function of transmitting and receiving a signal through a wireless channel such as band conversion and amplification of a signal. That is, the RF processing unit 5-10 up-converts the baseband signal provided from the baseband processing unit 5-20 into an RF band signal and transmits it through an antenna, and the RF band signal received through the antenna Is down-converted to a baseband signal. For example, the RF processing unit 5-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), and the like. I can. In the drawing, only one antenna is shown, but the terminal may include a plurality of antennas. In addition, the RF processing unit 5-10 may include a plurality of RF chains. Furthermore, the RF processing unit 5-10 may perform beamforming. For the beamforming, the RF processing unit 5-10 may adjust a phase and a magnitude of each of signals transmitted/received through a plurality of antennas or antenna elements. In addition, the RF processor may perform MIMO, and may receive multiple layers when performing the MIMO operation.

The baseband processing unit 5-20 performs a function of converting between a baseband signal and a bit stream according to the physical layer standard of the system. For example, when transmitting data, the baseband processing unit 5-20 generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit 5-20 restores a received bit stream through demodulation and decoding of the baseband signal provided from the RF processing unit 5-10. For example, in the case of the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processor 5-20 generates complex symbols by encoding and modulating a transmission bit stream, and subcarriers the complex symbols. After mapping to, OFDM symbols are constructed through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit 5-20 divides the baseband signal provided from the RF processing unit 5-10 in units of OFDM symbols, and maps them to subcarriers through fast Fourier transform (FFT). After restoring the received signals, the received bit stream is restored through demodulation and decoding.

The baseband processing unit 5-20 and the RF processing unit 5-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 5-20 and the RF processing unit 5-10 may be referred to as a transmission unit, a reception unit, a transmission/reception unit, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit 5-20 and the RF processing unit 5-10 may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit 5-20 and the RF processing unit 5-10 may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (eg, IEEE 802.11), a cellular network (eg, LTE), and the like. In addition, the different frequency bands may include a super high frequency (SHF) (eg, 2.NRHz, NRhz) band, and a millimeter wave (eg, 60GHz) band.

The storage unit 5-30 stores data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 5-30 may store information related to a second access node performing wireless communication using a second wireless access technology. In addition, the storage unit 5-30 provides stored data according to the request of the control unit 5-40.

The controller 5-40 controls overall operations of the terminal. For example, the control unit 5-40 transmits and receives signals through the baseband processing unit 5-20 and the RF processing unit 5-10. In addition, the control unit 5-40 writes and reads data in the storage unit 5-40. To this end, the control unit 5-40 may include at least one processor. For example, the controller 5-40 may include a communication processor (CP) that controls communication and an application processor (AP) that controls an upper layer such as an application program. Also, the controller 5-40 may control an operation of a terminal or an entity corresponding thereto according to various embodiments of the present disclosure.

6 is a block diagram showing the configuration of a base station according to an embodiment of the present invention.

As shown in the figure, the base station includes an RF processing unit 6-10, a baseband processing unit 6-20, a backhaul communication unit 6-30, a storage unit 6-40, and a control unit 6-50. It may include. The control unit 6-50 may further include a multiple connection processing unit 6-52.

The RF processing unit 6-10 performs a function for transmitting and receiving a signal through a wireless channel such as band conversion and amplification of a signal. That is, the RF processing unit 6-10 up-converts the baseband signal provided from the baseband processing unit 6-20 to an RF band signal, and then transmits it through an antenna, and an RF band signal received through the antenna. Is down-converted to a baseband signal. For example, the RF processing unit 6-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. In the drawing, only one antenna is shown, but the first access node may include a plurality of antennas. In addition, the RF processing unit 6-10 may include a plurality of RF chains. Furthermore, the RF processing unit 6-10 may perform beamforming. For the beamforming, the RF processing unit 6-10 may adjust a phase and a magnitude of each of signals transmitted and received through a plurality of antennas or antenna elements. The RF processor may perform a downlink MIMO operation by transmitting one or more layers.

The baseband processing unit 6-20 performs a function of converting between a baseband signal and a bit string according to the physical layer standard of the first wireless access technology. For example, when transmitting data, the baseband processing unit 6-20 generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit 6-20 restores a received bit stream through demodulation and decoding of the baseband signal provided from the RF processing unit 6-10. For example, in the case of the OFDM scheme, when transmitting data, the baseband processor 6-20 generates complex symbols by encoding and modulating a transmission bit stream, mapping the complex symbols to subcarriers, and then IFFT OFDM symbols are configured through calculation and CP insertion. In addition, when receiving data, the baseband processing unit 6-20 divides the baseband signal provided from the RF processing unit 6-10 in units of OFDM symbols, and reconstructs signals mapped to subcarriers through FFT operation. After that, the received bit stream is restored through demodulation and decoding. The baseband processing unit 6-20 and the RF processing unit 6-10 transmit and receive signals as described above. Accordingly, the baseband processing unit 6-20 and the RF processing unit 6-10 may be referred to as a transmission unit, a reception unit, a transmission/reception unit, a transceiver, a communication unit, or a wireless communication unit.

The backhaul communication unit 6-30 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 6-30 converts a bit stream transmitted from the base station to another node, for example, an auxiliary base station, a core network, etc., into a physical signal, and converts the physical signal received from the other node into a bit stream. Convert to

The storage unit 6-40 stores data such as a basic program, an application program, and setting information for the operation of the base station. In particular, the storage unit 6-40 may store information on bearers allocated to the connected terminal, measurement results reported from the connected terminal, and the like. In addition, the storage unit 6-40 may store information that is a criterion for determining whether to provide or stop providing multiple connections to the terminal. In addition, the storage unit 6-40 provides stored data according to the request of the control unit 6-50.

The controller 6-50 controls overall operations of the base station. For example, the control unit 6-50 transmits and receives signals through the baseband processing unit 6-20 and the RF processing unit 6-10 or through the backhaul communication unit 6-30. In addition, the control unit 6-50 writes and reads data in the storage unit 6-40. To this end, the controller 6-50 may include at least one processor. In addition, the controller 6-50 may control an operation of a base station or an entity corresponding thereto according to various embodiments of the present disclosure.

7 is a diagram illustrating a process of performing a general handover operation in a mobile communication system according to an embodiment of the present invention. In the embodiment of FIG. 7, the source cell 7-10 may be referred to as a source base station or a source node, and the target cell 7-20 may be referred to as a target base station or a target node.

The terminal 7-05 receives a predetermined RRC message including measurement configuration from the source cell 7-10 (7-25). The terminal 7-05 measures the signal quality of the serving cell and neighboring cells by applying the measurement setting information, and periodically or when a set event occurs (7-30), the collected cell measurement information is sourced from the source. Report to cell (7-10) (7-35).

The source cell 7-10 determines whether to trigger a general handover operation based on the reported cell measurement information (7-40). For example, when Event A3 (Neighbor becomes offset better than SpCell) is satisfied and cell measurement information is reported, the source cell 7-10 may determine a general handover. If it is determined to trigger the general handover, the source cell 7-10 may request a handover from one target cell 7-20 (7-40). For example, the source cell 7-10 may request the general handover through a predetermined inter-node message (7-45). For example, the inter-node message may be a handover (HO) request message, but is not limited thereto. Upon receiving the handover request, the target cell 7-20 accepts it and transmits handover configuration information necessary for the general handover operation to the source cell 7-10 (7-50). The target cell 7-20 may transmit an inter-node message including the handover configuration information to the source cell 7-10. The inter-node message may be a handover request response (HO request ack) message, but is not limited thereto.

The source cell 7-10 stores handover configuration information and additional configuration information received from the target cell 7-20 in a predetermined RRC message, and transmits the RRC message to the terminal 7-05. Do (7-55). For example, the RRC message may be an RRC connection reconfiguration message or an RRC reconfiguration message, and the RRC message may include a handover command. The configuration information includes at least one of ID of a target cell, frequency information, configuration information necessary for a random access operation to a target cell (dedicated preamble information, dedicated radio resource information, etc.), transmission power information, and C-RNTI information used in the target cell. One piece of information may be included.

Upon receiving the handover configuration information, the terminal 7-10 may start a handover operation (7-60). The terminal 7-05 starts a random access process to the target cell 7-20 based on the handover configuration information, and drives a timer T304 (7-60). At the same time, the terminal 7-05 stops transmitting and receiving data with the serving cell 7-10. This is because the terminal 7-10 has a single protocol stack. The terminal 7-10 may transmit the provided preamble to the target cell 7-20 based on configuration information required for a random access operation to the target cell (7-65). If the dedicated preamble is not provided, the terminal 7-05 may transmit one of the preambles used in the contention basis. Upon receiving the preamble, the target cell 7-20 transmits a random access response message (RAR) to the terminal 7-05 (7-70). The terminal 7-05 transmits msg3 to the target cell 7-20 using the UL grant information stored in the RAR (7-75). The msg3 stores an RRCConnectionReconfigurationComplete message in case of an LTE system and an RRCReconfigurationComplete message in case of an NR system. When the random access process is successfully completed, it is considered that the general handover has been successfully completed, and the terminal 7-05 stops the running T304 timer. If the general handover is not successfully completed until the T304 timer expires, the terminal 7-05 may regard it as a handover failure and declare a radio link failure (RLF).

8A and 8B are diagrams illustrating a process of using a dual active protocol stack in a process of performing a handover according to an embodiment of the present invention. Hereinafter, FIGS. 8A and 8B are collectively referred to as FIG. 8. In the embodiment of FIG. 8, the source cell may be referred to as a source base station or a source node, and the target cell may be referred to as a target base station or a target node.

When performing the general handover, the terminal stops data transmission and reception with the source cell when receiving the handover configuration information, and starts data transmission and reception with the target cell after the handover process is successful. Therefore, during the time period in which data transmission/reception is not possible (from the time when data transmission/reception with the source cell is stopped, data transmission/reception with the target cell starts, for example, from the time when the handover command is received, the random target cell is Access success time) Interruption time occurs.

If the terminal has a dual active protocol stack (DAPS), data transmission and reception with the source cell can be maintained during the time period. In an embodiment of the present invention, a handover in consideration of the terminal capability as described above is referred to as a dual active protocol stack (DAPS) handover. When DAPS handover is configured, the UE can simultaneously receive downlink data from the source cell and the target cell. However, simultaneous uplink data transmission to the source cell and the target cell may be possible only when a predetermined condition is satisfied due to a lack of terminal transmission power or signal interference. In order to minimize the terminal complexity, uplink data transmission during DAPS handover is possible in only one link, and uplink in which data transmission is performed may be switched from the source cell to the target cell at a specific time point.

At each major specific point in time, the active state of the dual protocol stack corresponding to the source cell and the target cell and the terminal operation are different. For example, referring to FIG. 8, the DAPS state and operation at each specific point in time may be as follows.

Before handover is performed (8-05), the UE uses only the protocol stack corresponding to the source cell. For example, before the terminal receives a handover command through an RRC reconfiguration message, the terminal can use only the protocol stack corresponding to the source cell.

Before DAPS handover configuration information is provided to the terminal and RACH is performed on the target cell (8-10), when the terminal receives DAPS handover configuration information through an RRCReconfiguration message, it configures a protocol stack corresponding to the target cell. However, the terminal still uses only the protocol stack corresponding to the source cell. Even if the protocol stack corresponding to the target cell is inactive, it is irrelevant. The protocol stack corresponding to the target cell may be activated or deactivated, and the terminal does not use a protocol stack for the target cell. The terminal does not deactivate the protocol stack for the source cell even when receiving the handover command.

During the RACH performance period (8-15), when the RACH operation starts, at least the PHY layer and the MAC layer are activated in the protocol stack corresponding to the target cell to perform the RACH operation. The UE transmits a random access preamble using the PHY layer and the MAC layer activated in the protocol stack of the target cell, monitors and receives the RAR, and transmits msg3 based on the UL grant included in the RAR. You can do it. At this time, the terminal still maintains data transmission/reception with the source cell. The terminal can be used for data transmission and reception with the source cell without deactivating the protocol stack for the source cell.

When the time point (8-20) for the terminal to transmit the HO (success) completion message to the target cell comes, the terminal activates at least some functions of the PHY layer, the MAC layer, the RLC layer, and the PDCP layer in the protocol stack corresponding to the target cell. , It should be able to process the HO success completion message, which is a signaling radio bearer. The terminal may transmit uplink data to the source cell at least before transmitting the HO success complete message to the target cell. The time at which the HO (success) completion message is transmitted is when the UE transmits an RA preamble to the target cell, receives a RAR message in response, and the UL grant is included in the corresponding RAR, using the corresponding UL grant, the target Since the HO completion message is transmitted to the cell (8-25), it may be after RAR is received.

After the UE receives the RAR from the target cell (8-25), all of the dual active protocol stacks may be activated. The UE maintains data transmission/reception with the source cell until a specific point in time arrives after RAR reception. In addition, the time point at which the UE can maintain the source cell and downlink data reception and the time point at which the uplink data transmission can be maintained may be different. The UE may transmit uplink data to the source cell until the HO success complete message is transmitted to the target cell, but downlink data reception is possible until a specific point in time thereafter.

After the UE releases the source cell (8-30), the protocol stack corresponding to the source cell is also released. From then on, the UE can use only the protocol stack corresponding to the target cell.

9 is a diagram illustrating a process of performing a DAPS handover according to an embodiment of the present invention. In the embodiment of FIG. 9, the source gNB 9-04 may be referred to as a source cell, a source base station, or a source node, and the target gNB 9-06 may be referred to as a target cell, a target base station, or a target node. . In addition, the system of FIG. 9 may further include a user plane function (UPF) node 9-08 and an access and mobility management function (AMF) node 9-10.

The terminal (9-02) switches to the connection mode with the source base station (9-04) through the RRC establishment or RRC resume process (9-12). The terminal 9-02 having DAPS handover support capability may report to the source base station 9-04 that it supports DAPS handover. For example, the terminal 9-02 may transmit the UE capability information to the source base station 9-04 by including an indicator indicating that DAPS HO is supported. The source base station 9-04 may transmit an RRC message including a measurement configuration to the terminal 9-02 (9-16). The RRC message may be an RRC reconfiguration message, but is not limited thereto. The source base station 9-04 may set the measurement configuration to the terminal 9-2 by using an RRCReconfiguration message for the purpose of supporting mobility (9-16).

The terminal 9-02 may check whether a measurement report event is triggered or whether a periodic condition for measurement report is satisfied based on the measurement configuration. For example, when a measurement report event is triggered (9-18), the terminal 9-02 may report a measurement report to the source base station 9-04 (9-20). The source base station 9-04 receiving the measurement report may determine to perform handover with a specific neighbor base station based on the cell measurement information included in the measurement report (9-22). When it is determined that the source base station 9-04 performs handover, the source base station 9-04 may perform a handover preparation procedure with the target base station 9-6 (9-24). The source base station 9-04 transmits a handover request message to the target base station 9-06, and the target base station 9-06 responds to it (for example, a handover request response message). May be transmitted to the source base station 9-04 (9-24). The handover request message may include an indicator indicating that the terminal will perform DAPS handover or an indicator indicating that the terminal can perform DAPS handover. The response message may include configuration information required when the terminal accesses the target cell.

Upon receiving the response message, the source base station 9-04 may provide the terminal 9-02 with configuration information included in the response message. The source base station 9-04 may transmit an RRC message including information received from the target cell and additional configuration information to the terminal 9-02. For example, the source base station 9-04 may transmit handover configuration information and ReconfigurationWithSync to the terminal 9-02 using RRCReconfiguration (9-26). The handover configuration information may include an indicator indicating that the handover to the terminal 9-02 is handover using DAPS.

When receiving the RRC reconfiguration message including handover-related information, the terminal 9-02 may check whether the indicator is included in the message. If the indicator is not included, the terminal 9-02 may perform the terminal operation after receiving the HO configuration described in the embodiment of FIG. 7. The terminal 9-02 may start a random access operation to the target base station 9-06 based on the RRC reconfiguration message (9-36). The terminal 9-02 may transmit a random access preamble to the target base station 9-06. The terminal 7-02, which has received the indicator through the RRC reconfiguration message, transmits the first preamble to the target cell 9-06, and the source cell 9-04 and data Can maintain transmission and reception (9-28, 9-34).

Terminal user data transmitted and received through the source cell 9-04 is transmitted to the end user through the UPF 9-08 (9-30). The source cell 9-04 may forward downlink data of the terminal to the target cell 9-06 (9-32). This is because the signal quality of the link with the source cell 9-04 rapidly deteriorates, and data transmission/reception may become difficult any more. The terminal 9-02 performs random access to the target cell 9-06 (9-36). The terminal 9-02 transmits an RRCReconfiguratonComplete message to the target cell 9-06 (9-38). If the RRC message is successfully transmitted, it means that the handover to the target cell 9-06 has been successfully completed. The terminal 9-02 may perform uplink data transmission with the source cell 9-04 until the RRC message is successfully transmitted. When the UE 9-02 receives a UL grant (uplink scheduling information) from the target cell 9-06, the UE 9-02 performs uplink from the target cell 9-04 to the target cell 9-06. Can be switched.

Upon receiving the RRCReconfigurationComplete message, the target cell 9-06 may determine to release the connection between the terminal 9-02 and the source cell 9-04 (9-40). The target cell 9-06 may transmit a message requesting the release of the connection to the source cell 9-06 (9-42). For example, the target cell 9-06 may transmit a HO connection setup complete message to the source cell 9-04, and the message is disconnected between the source cell 9-04 and the terminal 9-02. Can be ordered. The connection release request message may include information requesting to stop transmitting and receiving data through the source base station 9-04.

Upon receiving the request, the source cell 9-04 stops transmitting and receiving data with the terminal 9-02. The source cell 9-04 provides a sequence number (SN) status transfer to the target cell (9-44). The SN status transfer may include UL PDCP status and DL SN to use. The information is used to smoothly perform data transmission/reception with the terminal 9-02 in the target cell 9-06.

The target cell 9-06 may instruct the terminal 9-02 to release the connection with the source cell by using a predetermined RRC message (9-46). The RRC message may be an RRC reconfiguration message and may include information indicating disconnection of the source gNB. Upon receiving the message, the terminal 9-02 releases the connection with the source cell 9-04 (9-52). The terminal 9-02 may receive the RRC reconfiguration message, release the connection with the source cell 9-04, and may not receive data from the source base station from that point in time. The terminal 9-02 may transmit a response message to the message to the target cell 9-06 (9-48). The response message may be an RRC reconfiguration complete message.

As another option, when the terminal 9-02 successfully transmits the RRCReconfigurationComplete message to the target cell 9-06 or after a predetermined offset time, the connection with the source cell 9-04 is implicitly released. May be.

Upon receiving the response message from the terminal, the target cell 9-06 requests U-plane switching from the AMF 9-10 (9-54). Upon receiving the request, the AMF 9-10 transmits an End Marker to the source cell 9-04 (9-56). Upon receiving the end marker, the source cell 9-04 releases the UE context for the terminal 9-02 (9-58).

Hereinafter, some configurations in the embodiment of FIG. 9 will be described in more detail.

In step (9-14) of FIG. 9, the terminal 9-02 may report to the serving base station 9-04 that the terminal supports DAPS in a certain band combination through the UE capability reporting process. The terminal 9-02 may receive a UE capability request message from the source base station 9-04 and report the UE capability in response thereto. In this case, the UE capability may include an indicator indicating whether DAPS is supported for each BandCombination. For example, the indicator may be 1-bit information and may indicate whether DAPS is supported by 1-bit.

In step (9-26) of FIG. 9, the terminal 9-02 may receive an RRCReconfiguration message indicating DAPS from the source cell 9-04. The UE can check whether the DAPS indication is included in this message, and if the indicator is included, it can perform a DAPS handover operation, and if the indicator is not included, it can perform a general handover operation.

Meanwhile, after receiving the message of steps 9-26, the terminal 9-02 may perform sub-operations for each of the following procedural points. In this procedure for comparison, the notation for a time point is replaced as follows, but the notation for that time point is not limited thereto:

T1: When the UE receives the RRCReconfiguration with DAPS indication from the source cell, in FIG. 9 (9-26)

T2: UL switching time point, that is, the time point when the UE initially receives the UL grant from the target cell, it may be between (9-36) and (9-38) in FIG.

T2-1: HO complete / RA complete, (9-38) in FIG. 9 or RAR may be received.

T2’: The later point of [T2 and SFN (system frame number) acquisition time of target cell]

T2-1’: The later point of [T2-1 and SFN acquisition time of target cell]

T3: source link release step (9-52) in FIG. 9

Meanwhile, the time points T1, T2, T2-1, T2', T2-1', and T3 defined above may be defined based on a slot, a subframe, or a symbol for transmitting and receiving a message. For example, the time point T1 may mean a slot in which RRC reconfiguration is received, and the time point T2 may mean a slot in which the UL grant is received. Similar to other viewpoints, the viewpoint may be defined by applying the concept of a slot, a subframe, or a symbol. In addition, applying the setting from a specific point T among the various points in time means applying the setting from the corresponding slot, applying the setting from the next slot of the corresponding slot, and applying the setting from after a preset slot or symbol from the corresponding slot. It can be interpreted in various ways. Deactivating the setting from a specific point T is interpreted in various ways as releasing the setting from the corresponding slot, releasing the setting from the next slot of the corresponding slot, and releasing the setting from after a preset slot or symbol from the corresponding slot, etc. can do.

The following structure of ASN.1 can be used for signals of the operations mentioned below. The structure below may correspond to the structure of the cell group config included in the RRC reconfiguration message received in steps 9-26.

- CellGroupConfig

> ReconfigWithSync

>> DAPS indication

>> ServingCellCofnig> BWP-Uplink

>>> Bwp-Id

>>> Pucch-Config

>>>> resourceSetToAddModList

>>>> resourceSetToReleaseList

The BWP processing procedure can operate as follows.

When the UE 9-02 receives the RRCReconfiguration message with the DAPS indication received at the time T1 while performing the procedure of FIG. 9, the UE 9-02 performs the following operations with respect to the UL and/or DL BWP release and AddModList included in this message. I can. In addition, the source base station 9-04 may configure an RRC reconfiguration message so that the terminal performs the following operation, and may signal the terminal 9-02. When the DAPS indicator is included according to the following operation, the terminal 9-02 interprets the BWP release list, BWP add mod list, and PUCCH config included in the corresponding RRC reconfiguration message as follows, and applies the related settings at a specific time. can do.

-The BWP release list is applied to the BWP of the source cell.

> BWP explicitly indicated in the release list is released immediately to T1.

> BWPs not indicated in the release list autonomously release to T3.

For example, if BWP 1, 2, and 3 are set for the source cell, and information indicating BWP3 is included in the BWP release list, BWP3 of the source cell is released immediately from T1, and BWP1 of the source cell, BWP2 can be released to T3.

-The BWP indicated by the BWP addmod list is set as the BWP of the target cell in T1.

For example, if information indicating BWP4 is included in the BWP addmodlist, it is interpreted as information indicating the BWP of the target cell, not the BWP of the source cell, and BWP4 may be set for the target cell.

-In the case of UL, when the resourceSetTorelease list of the PUCCH-Config of the BWP set in the BWP addModList is indicated, the PUCCH resource of the BWP of the source cell specified by the corresponding BWP id can be released in T1. When the resourceSetToAddModList of the PUCCH-Config of the BWP set in the BWP AddModList of the UL is indicated, the PUCCH resource of the BWP of the target cell specified by the corresponding BWP id can be added or modified to T1.

For example, if there is BWP1 in the resource set to release list of the PUCCH-config, the PUCCH resource of the BWP1 of the source cell can be released. For example, if the resource set to add list of the PUCCH-config includes BWP1, PUCCH resources corresponding to BWP1 may be added or modified with respect to the target cell. The setting operation for the PUCCH resource may be performed in T1.

When the DAPS indicator is included in the RRC reconfiguration message, the UE may manage BWP-related configuration in the same manner as described above. In the case of a general handover other than a DAPS handover, the newly received BWP configuration information is reset at the time point T1, but in the DAPS handover according to an embodiment of the present invention, the source cell and the target cell are differently analyzed according to the BWP-related information. It can be done, and the timing of applying the BWP setting information may be different.

The PUCCH configuration and SRS configuration processing procedure may operate as follows.

For the Active BWP of source Pcell, the UE 9-02 releases the PUCCH resource indicated in the resourceSetToReleaseList in T1, is signaled in the addmodList, or can perform CSI report up to T3 using the currently set PUCCH resource. . In addition, it is possible to stop and stop SRS transmission up to T2 by using the PUCCH resource. The PUCCH resource used by the source cell may be determined in the same manner as described above, and the last time at which the UE 9-02 can transmit the CSI-report before releasing the connection with the source cell and the last time at which the SRS can be transmitted. The viewpoint may be different.

The UE 9-02 sets the PUCCH resource indicated in resourceSetToAddModList in T1 for the initial BWP of target Pcell, and performs CSI reporting from the time T2-1' and SRS transmission from the time T2' using the set PUCCH resource. I can. The PUCCH resource to be used in the target cell may be determined in the same manner as described above, and a time point at which CSI reporting for the target cell can start and a time point at which SRS transmission can start may be different.

When the DAPS indicator is included in the RRC reconfiguration message, the UE may manage PUCCH resource configuration, CSI reporting, and SRS transmission in the same manner as described above. The operation of the DAPS handover as described above, in the case of a general handover, resets the pucch resource of the corresponding BWP at the time of receiving the HO command, and. It may be different from initiating CSI reporting in T2-1` using the PUCCH resource of the initial BWP in the target cell.

In the measurement setting execution process, as follows, first information may be processed in a first manner, and second information may be processed in a second manner.

-First information: MeasObject, ReportConfig, measId

-First method: The current setting can be removed and new setting information can be applied to T1. The terminal may apply a new measurement configuration to T2-1 and perform measurement according to the new configuration.

-Second information: MeasGapConfig

-Method 2: Remove the current setting in T1. Then, apply the new settings to T3. In other words, you can release the measurement gap in T1 and set a new measurement gap in T3.

-Instead of the above 2 method, the 2-1 method may be used. In the 2-1 method, the source cell transmits the information contained in the current measGapConfig to the target cell, and the target cell creates a measGapconfig applicable to both the source cell and the target cell, and transfers the measurement gap setting information back to the source cell. May give measurement gap configuration information in T1 as measGapConfig information included in the RRCReconfiguration message. The measurement gap setting information may include the following information, and the terminal may process the information in the following manner.

> A. measGap information to be applied to the source cell, that is, time information not to be scheduled from the source cell to the terminal and measGap information to be applied to the target cell (start time and duration), that is, time information not to be scheduled from the target cell to the terminal (start Time and duration) can be separately informed. or;

> B. One unified measGap information, that is, during this time, both the source cell and the target cell may inform the UE of time information (start time and duration) not to perform scheduling.

> In the case of A, the UE does not need to monitor the cell during the measGap time for each cell.

> In the case of B, the UE may not monitor any cells during the integrated measGap time.

When the DAPS indicator is included in the RRC reconfiguration message, the UE may apply and manage measurement configuration and measurement gap configuration in the same manner as described above. The operation of the DAPS handover as described above, in the case of a general handover, resets the PUCCH resource of the corresponding BWP at the time of receiving the HO command, and. It may be different from initiating CSI reporting in T2-1` using the PUCCH resource of the initial BWP in the target cell.

In addition, the embodiments disclosed in the present specification and drawings are merely provided specific examples for easy explanation and understanding of the present invention, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed that all changes or modified forms derived based on the technical features of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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