Method and apparatus for performing communication in a wireless communication system

Abstract

A method for performing communication during a handover process performed by a user equipment (UE) includes: receiving uplink (UL) grant configuration information via an RRC reconfiguration message, selecting an SSB among multiple SSBs included in the UL grant information, determining a UL grant corresponding to the selected SSB and a HARQ process corresponding to the UL grant based on the UL grant information, and sending a reconfiguration completion message in the determined UL grant corresponding to the selected SSB using the HARQ process.

Description

Technical Field

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for determining a synchronization signal block (SSB) and a hybrid automatic repeat request (HARQ) process corresponding to an uplink (UL) grant configured for a random access channel-less (RACH-less) handover. Background Art

[0002] In order to meet the demand for wireless data traffic that has increased since the deployment of the fourth generation (4G) communication system, efforts have been made to develop improved fifth generation (5G) or quasi-5G communication systems. 5G or quasi-5G communication systems are also referred to as "super 4G networks" or "post-long term evolution (LTE) systems". 5G communication systems are considered to be implemented in higher frequency (mmWave) bands (e.g., 60GHz bands) in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed for 5G communication systems. In addition, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, collaborative multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid frequency shift keying (FSK) and Feher quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0003] The Internet, as a human-centered connected network where humans generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities such as things exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of IoT technology and big data processing technology through connection with a cloud server, has emerged. Since IoT implementation has required technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology", sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. Such an IoT environment can provide smart Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. Through the integration and combination between existing information technology (IT) and various industrial applications, IoT can be applied to various fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC, and M2M communications can be implemented through beamforming, MIMO, and array antennas. The application of cloud RAN, which is the above-mentioned big data processing technology, can also be considered as an example of the fusion between 5G technology and IoT technology.

[0005] As described above, various services can be provided according to the development of wireless communication systems, and thus a method for easily providing such services is required. Summary of the invention

[0006] 'Technical issues'

[0007] When the UE performs handover, a delay occurs due to performing random access.

[0008] "Technical solution"

[0009] A method for performing communication during a handover process performed by a user equipment (UE) includes: receiving uplink (UL) grant configuration information via an RRC reconfiguration message, selecting an SSB among multiple SSBs included in the UL grant information, determining a UL grant corresponding to the selected SSB and a HARQ process corresponding to the UL grant based on the UL grant information, and sending a reconfiguration completion message in the determined UL grant corresponding to the selected SSB using the HARQ process. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is an example diagram of mapping between HARQ process ID and configured UL grant based on the above method; and

[0011] Figure 2 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0012] Figure 3 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0013] Figure 4 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0014] Figure 5 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0015] Figure 6 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0016] Figure 7 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0017] Figure 8 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0018] Fig. 9 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0019] Fig.10 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant at a UE according to an embodiment of the present disclosure; and

[0020] Fig.11 is a flow chart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure; and

[0021] Fig.12 is a diagram illustrating a UE 1200 according to an embodiment of the present disclosure; and

[0022] Fig.13 is a diagram illustrating a base station 1300 according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] In the current handover process, the initial beam alignment between the UE and the target cell occurs via a random access procedure. In order to reduce the handover delay, RACH-free handover needs to be studied.

[0024] A method and apparatus for performing communication in a handover procedure are provided. According to an embodiment, the method for performing communication in a handover procedure performed by a UE includes: receiving uplink (UL) grant configuration information via an RRC reconfiguration message; selecting an SSB among a plurality of SSBs included in the UL grant information; determining a UL grant corresponding to the selected SSB and a HARQ process corresponding to the UL grant based on the UL grant information; and sending a reconfiguration complete message in the determined UL grant corresponding to the selected SSB using the HARQ process.

[0025] Before proceeding to the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives are meant to include, but are not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated therewith" and their derivatives may mean to include, be included within, be interconnected with, contain, be contained within, be connected to or connected with, be coupled to or coupled with, be communicative with, cooperate with, interleave, juxtapose, be proximate to, be bound to or bound with, have, have the property of, etc.; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0026] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and implemented in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or a part thereof that are suitable for being implemented in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disc (DVD) or any other type of memory. "Non-transitory" computer-readable media does not include wired, wireless, optical or other communication links that send temporary electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and rewrite it later, such as rewritable optical disks or erasable storage devices.

[0027] Definitions for certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0028] "Invention Mode"

[0029] Discussed below Figures 1 to 13 The various embodiments used to describe the principles of the present disclosure in this patent document are illustrative only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0030] The present application provides a method and apparatus for performing communication in a handover process.

[0031] In order to achieve the above-mentioned objectives, the present application adopts the following technical solution: a method for performing communication by a UE, comprising: receiving uplink (UL) authorization configuration information via an RRC reconfiguration message; selecting an SSB among multiple SSBs included in the UL authorization information; determining a UL authorization corresponding to the selected SSB and a HARQ process corresponding to the UL authorization based on the UL authorization information; and sending a reconfiguration completion message in the determined UL authorization corresponding to the selected SSB using the HARQ process.

[0032] In some embodiments, determining the UL grant and the HARQ process includes: identifying a period for configuring the UL grant and a number of SSBs associated with the UL grant based on the UL grant information; and determining the UL grant and the HARQ process based on the current symbol using the identified period and the identified number.

[0033] In some embodiments, determining the UL grant and the HARQ process includes: identifying a period for configuring the UL grant and a number of SSBs associated with the UL grant based on the UL grant information; and determining the UL grant based on a current symbol using the identified period and the identified number, and determining the HARQ process based on the current symbol using the identified period.

[0034] In some embodiments, selecting an SSB includes: obtaining a list indicating SSBs for multiple UL authorization configurations from UL authorization configuration information; and wherein selecting an SSB includes selecting an SSB for each of the multiple UL authorization configurations, and a UL authorization corresponding to the selected SSB and a HARQ process corresponding to the UL authorization are determined based on each of the multiple UL authorization configurations.

[0035] In some embodiments, determining the HARQ process includes: identifying an offset value for each of a plurality of UL grant configurations; and determining a HARQ process corresponding to the UL grant based on the identified offset.

[0036] A method for performing communication by a base station on an unlicensed band, comprising: sending uplink (UL) grant configuration information via an RRC reconfiguration message; and receiving a reconfiguration completion message in a UL grant corresponding to an SSB selected at the UE from a user equipment (UE) using a HARQ process, wherein the SSB is selected from among multiple SSBs included in the UL grant information, and the UL grant corresponding to the selected SSB and the HARQ process corresponding to the UL grant are determined based on the UL grant information.

[0037] A user equipment (UE) for performing communication in a wireless communication system, the UE comprising: a transceiver; and a processor coupled to the transceiver and configured to: control the transceiver to receive uplink (UL) grant configuration information via an RRC reconfiguration message, select an SSB from among multiple SSBs included in the UL grant information, determine a UL grant corresponding to the selected SSB and a HARQ process corresponding to the UL grant based on the UL grant information, and control the transceiver to send a reconfiguration completion message in the determined UL grant corresponding to the selected SSB using the HARQ process.

[0038] A base station for performing communication in a wireless communication system, the base station comprising: a transceiver; and a processor coupled to the transceiver and configured to: control the transceiver to send uplink (UL) grant configuration information via an RRC reconfiguration message; and control the transceiver to receive a reconfiguration completion message in a UL grant corresponding to an SSB selected at the UE from a user equipment (UE) using a HARQ process, wherein the SSB is selected from among a plurality of SSBs included in the UL grant information, and the UL grant corresponding to the selected SSB and the HARQ process corresponding to the UL grant are determined based on the UL grant information.

[0039] Throughout the disclosure, the expression "at least one of a, b, and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. Throughout the specification, a layer (or layer arrangement) may also be referred to as an entity. Hereinafter, the operating principle of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or configurations are not described in detail because they would obscure the present disclosure with unnecessary details. The terms used in the specification are defined in consideration of the functions used in the present disclosure and can be changed according to the intention of the user or operator or a common method. Therefore, the definition of the terms is understood based on the entire description of this specification.

[0040] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted or roughly shown. In addition, the size of each element does not exactly correspond to the actual size of each element. In each accompanying drawing, the same or corresponding elements are represented by the same reference numerals.

[0041] By referring to the following detailed description and drawings of the embodiments of the present disclosure, the advantages and features of the present disclosure and the methods for completing it can be more easily understood. However, the present disclosure can be embodied in many different forms and should not be interpreted as being limited to the embodiments set forth herein; on the contrary, these embodiments of the present disclosure are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the present disclosure to those of ordinary skill in the art. Therefore, the scope of the present disclosure is defined by the appended claims. Throughout the specification, the same reference numerals represent the same elements. It will be understood that the blocks in the flowchart or the combination of flowcharts can be executed by computer program instructions. Because these computer program instructions can be loaded into a processor of a general-purpose computer, a special-purpose computer, or another programmable data processing device, the instructions executed by the processor of the computer or another programmable data processing device create units for performing the functions described in the flowchart blocks.

[0042] Computer program instructions may be stored in a computer-usable or computer-readable memory capable of directing a computer or another programmable data processing device to implement functions in a specific manner, so that the instructions stored in the computer-usable or computer-readable memory are also capable of producing a manufactured item containing instruction units for performing the functions described in the (multiple) flowchart blocks. The computer program instructions may also be loaded into a computer or another programmable data processing device, so that when a series of operations are performed in the computer or another programmable data processing device, the instructions for operating the computer or other programmable data processing device by generating a computer-run process may provide operations for performing the functions described in the (multiple) flowchart blocks.

[0043] In addition, each block may represent a module, segment or part of a code that includes one or more executable instructions for running (multiple) specified logical functions. It should also be noted that in some alternative implementations, the functions mentioned in the blocks may not occur in order. For example, two consecutive blocks may also be run simultaneously or in reverse order, depending on the functions corresponding thereto.

[0044] As used herein, the term "unit" represents a software element or hardware element such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and performs a specific function. However, the term "unit" is not limited to software or hardware. A "unit" can be formed in an addressable storage medium, or can be formed to operate one or more processors. Therefore, for example, the term "unit" can include an element (e.g., a software element, an object-oriented software element, a class element, and a task element), a process, a function, an attribute, a flow, a subroutine, a program code segment, a driver, a firmware, a microcode, a circuit, data, a database, a data structure, a table, an array, or a variable.

[0045] The functions provided by the elements and "units" can be combined into a smaller number of elements and "units", or can be divided into additional elements and "units". In addition, the elements and "units" can be implemented as one or more central processing units (CPUs) in a reproduction device or a secure multimedia card. In addition, in an embodiment of the present disclosure, a "unit" may include at least one processor. In the following description of the present disclosure, well-known functions or configurations are not described in detail because they will obscure the present disclosure with unnecessary details.

[0046] Hereinafter, for convenience of explanation, the present disclosure uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard. However, the present disclosure is not limited to the terms and names, and may also be applied to systems complying with other standards.

[0047] In the present disclosure, for the convenience of explanation, the evolved Node B (eNB) may be used interchangeably with the next generation Node B (gNB). That is, the base station (BS) described by the eNB may represent the gNB. In the following description, the term "base station" refers to an entity for allocating resources to the user equipment (UE), and may be used interchangeably with at least one of the gNode B, eNode B, Node B, base station (BS), wireless access unit, base station controller (BSC), and nodes on the network. The term "terminal" may be used interchangeably with the user equipment (UE), mobile station (MS), cellular phone, smart phone, computer, or multimedia system capable of performing communication functions. However, the present disclosure is not limited to the above examples. Specifically, the present disclosure may be applied to the 3GPP New Radio (NR) (or fifth generation (5G)) mobile communication standard. In the following description, for the convenience of explanation, the term eNB may be used interchangeably with the term gNB. That is, the base station interpreted as the eNB may also indicate the gNB. The term UE may also indicate a mobile phone, NB-IoT device, sensor, and other wireless communication devices.

[0048] In the fifth generation wireless communication system operating in the higher frequency (mmWave) band, the UE and the gNB communicate with each other using beamforming. Beamforming technology is used to mitigate propagation path loss and increase propagation distance for communication at higher frequency bands. Beamforming uses high-gain antennas to enhance transmission and reception performance. Beamforming can be classified into transmit (TX) beamforming performed at the transmitting end and receive (RX) beamforming performed at the receiving end. Generally, TX beamforming increases directivity by allowing the area reached by propagation to be densely located in a specific direction using multiple antennas. In this case, the aggregation of multiple antennas can be referred to as an antenna array, and each antenna included in the array can be referred to as an array element. The antenna array can be configured in a variety of forms, such as a linear array, a planar array, and the like. The use of TX beamforming leads to an increase in the directivity of the signal, thereby increasing the propagation distance. In addition, since the signal is hardly transmitted in a direction other than the directional direction, the signal interference acting on the other receiving end is significantly reduced. The receiving end can perform beamforming on the RX signal by using an RX antenna array. RX beamforming increases the RX signal strength sent in a specific direction by allowing propagation to be concentrated in a specific direction, and excludes signals sent in directions other than the specific direction from the RX signal, thereby providing the effect of blocking interference signals. By using beamforming technology, the transmitter can form multiple transmit beam patterns in different directions. Each of these transmit beam patterns can also be referred to as a transmit (TX) beam. Since each narrow TX beam provides coverage to a portion of a cell, a wireless communication system operating at a high frequency uses multiple narrow TX beams to transmit signals in a cell. The narrower the TX beam, the higher the antenna gain, and therefore the greater the propagation distance of the signal sent using beamforming. The receiver can also form multiple receive (RX) beam patterns in different directions. Each of these receive patterns can also be referred to as a receive (RX) beam.

[0049] The fifth generation wireless communication system supports independent mode of operation as well as dual connection (DC). In DC, a multi-Rx / Tx UE can be configured to utilize resources provided by two different nodes (or NBs) connected via a non-ideal backhaul. One node acts as a master node (MN), and the other node acts as a secondary node (SN). MN and SN are connected via a network interface, and at least MN is connected to the core network. NR also supports multi-RAT dual connection (MR-DC) operation, whereby a UE in RRC_CONNECTED is configured to utilize radio resources provided by two different schedulers located in two different nodes connected via a non-ideal backhaul and providing E-UTRA (ie, if the node is an ng-eNB) or NR access (ie, if the node is a gNB). In NR, for a UE in RRC_CONNECTED that is not configured with CA / DC, there is only one serving cell including a primary cell. For a UE in RRC_CONNECTED that is configured with CA / DC, the term "serving cell" is used to refer to a cell set including (multiple) special cells and all secondary cells. In NR, the term Master Cell Group (MCG) refers to a set of serving cells associated with a master node, including a PCell and optionally one or more SCells. In NR, the term Secondary Cell Group (SCG) refers to a set of serving cells associated with a secondary node, including a PSCell and optionally one or more SCells. In NR, PCell (primary cell) refers to a serving cell in an MCG operating on the primary frequency, where the UE performs an initial connection establishment procedure or initiates a connection reestablishment procedure. In NR, for UEs configured with CA, an SCell is a cell that provides additional radio resources on top of a special cell. Primary SCG cell (PSCell) refers to a serving cell in an SCG, where the UE performs random access when performing a reconfiguration with a synchronization procedure. For dual connectivity operation, the term SpCell (i.e., special cell) refers to the PCell of an MCG or the PSCell of an SCG, otherwise the term special cell refers to the PCell.

[0050] In the fifth generation wireless communication system, the Node B (gNB) or base station in the cell broadcasts a synchronization signal, and the PBCH block (SSB) includes the primary synchronization signal and the secondary synchronization signal (PSS, SSS) and system information. The system information includes common parameters required for communication in the cell. In the fifth generation wireless communication system (also called the next generation radio or NR), the system information (SI) is divided into MIB and multiple SIBs, where:

[0051] The MIB is always sent on the PBCH with a period of 80 ms and repeated within 80 ms, and it includes the parameters required to obtain SIB1 from the cell.

[0052] SIB1 is transmitted on DL-SCH with a periodicity of 160ms and variable transmission repetition. The default transmission repetition period of SIB1 is 20ms, but the actual transmission repetition period depends on the network implementation. SIB1 includes information about the availability and scheduling of other SIBs (e.g., mapping of SIBs to SI messages, periodicity, SI window size), with an indication of whether one or more SIBs are provided only on demand, and the configuration required for the UE to perform the SI request in this case. SIB1 is a cell-specific SIB;

[0053] SIBs except SIB1 are carried in a System Information (SI) message, which is sent on the DL-SCH. Only SIBs with the same periodicity can be mapped to the same SI message.

[0054] In the fifth generation wireless communication system, the physical downlink control channel (PDCCH) is used to schedule DL transmission on PDSCH and UL transmission on PUSCH, wherein the downlink control information (DCI) on PDCCH includes: downlink assignments containing at least modulation and coding formats, resource allocations and hybrid ARQ information related to DL-SCH; uplink scheduling authorizations containing at least modulation and coding formats, resource allocations and hybrid ARQ information related to UL-SCH. In addition to scheduling, PDCCH can also be used to: activate and deactivate configured PUSCH transmissions using configured authorizations; activate and deactivate semi-persistent transmission of PDSCH; notify one or more UEs of the time slot format; notify one or more UEs of which (multiple) PRBs and (multiple) OFDM symbols the UE can assume are not transmitted for the UE; transmission of TPC commands for PUCCH and PUSCH; transmission of one or more TPC commands for SRS transmission by one or more UEs; convert the activated bandwidth portion of the UE; initiate a random access procedure. The UE monitors a set of PDCCH candidates in the configured monitoring opportunities in one or more configured control resource sets (CORESETs) according to the corresponding search space configuration. A CORESET consists of a set of PRBs with a duration of 1 to 3 OFDM symbols. Resource unit resource element groups (REGs) and control channel elements (CCEs) are defined within a CORESET, where each CCE includes a group of REGs. The control channel is formed by the aggregation of CCEs. Different code rates for the control channel are achieved by aggregating different numbers of CCEs. Interleaved and non-interleaved CCE to REG mapping are supported in a CORESET. Polarization coding is used for PDCCH. Each resource element group carrying PDCCH carries its own DMRS. QPSK modulation is used for PDCCH.

[0055] In the fifth generation wireless communication system, a list of search space configurations is signaled by the GNB for each configured BWP, where each search configuration is uniquely identified by an identifier. The identifier of the search space configuration to be used for a specific purpose (such as paging reception, SI reception, random access response reception) is explicitly signaled by the gNB. In NR, the search space configuration includes the parameters Monitoring-periodicity-PDCCH-slot, Monitoring-offset-PDCCH-slot, Monitoring-symbols-PDCCH-within-slot and duration. The UE uses the parameters PDCCH monitoring period (Monitoring-periodicity-PDCCH-slot), PDCCH monitoring offset (Monitoring-offset-PDCCH-slot) and PDCCH monitoring mode (Monitoring-symbol-PDCCH-within-slot) to determine the (multiple) PDCCH monitoring opportunities within the slot. The PDCCH monitoring opportunity exists in time slots "x" to "x+duration", where the time slot with number "x" in the radio frame with number "y" satisfies the following equation:

[0056] (y*(number of slots in a radio frame)+x-monitoring-offset-PDCCH-slot)mod(monitoring-period-PDCCH-Slot)=0;

[0057] The starting symbol of the PDCCH monitoring opportunity in each time slot with a PDCCH monitoring opportunity is given by monitoring-symbol-PDCCH-inside-time slot. The length of the PDCCH monitoring opportunity (in symbols) is given in the CORESET associated with the search space. The search space configuration includes an identifier of the CORESET configuration associated with it. A list of CORESET configurations is signaled by the GNB for each configured BWP, where each CORESET configuration is uniquely identified by an identifier. Note that each radio frame has a duration of 10ms. A radio frame is identified by a radio frame number or a system frame number. Each radio frame includes several time slots, where the number of time slots in a radio frame and the duration of the time slots depend on the subcarrier spacing. The number of time slots in a radio frame and the duration of the time slots depend on the radio frame of each supported SCS, which is predefined in NR. Each CORESET configuration is associated with a TCI (Transmission Configuration Indicator) state list. One DL RS ID (SSB or CSIRS) is configured per TCI state. The TCI state list corresponding to the CORESET configuration is signaled by the gNB via RRC signaling. One of the TCI states in the TCI state list is activated by the gNB and indicated to the UE. The TCI state indicates the DL TX beam used by the gNB to transmit the PDCCH in the PDCCH monitoring opportunity in the search space (the DL TX beam and the SSB / CSI RS of the TCI state are QCL).

[0058] In the fifth generation wireless communication system, bandwidth adaptation (BA) is supported. With BA, the receiving and transmitting bandwidth of the UE does not need to be as large as the bandwidth of the cell and can be adjusted: the width can be commanded to change (e.g., shrink during low activity periods to save power); the position can be moved in the frequency domain (e.g., to increase scheduling flexibility); and the subcarrier spacing can be commanded to change (e.g., to allow different services). A subset of the total cell bandwidth of a cell is called a bandwidth part (BWP). BA is achieved by configuring (multiple) BWPs for the RRC-connected UE and telling the UE which configured BWP is currently the activated one. When BA is configured, the UE only has to monitor the PDCCH on that activated BWP, i.e., it does not have to monitor the PDCCH on the entire DL frequency of the serving cell. In the RRC connected state, for each configured serving cell (i.e., PCell or SCell), the UE is configured with one or more DL and UL BWPs. For an activated serving cell, there is always an activated UL and DL BWP at any point in time. BWP conversion for the serving cell is used to activate an inactive BWP and deactivate an activated BWP each time. The BWP conversion is controlled by the PDCCH indicating the downlink assignment or uplink grant, by the bwp-InactivityTimer, by RRC signaling, or by the MAC entity itself when initiating the random access procedure. When adding a SpCell or activating an SCell, the DL BWP and UL BWP indicated by firstActiveDownlinkBWP-Id and firstActiveUplinkBWP-Id, respectively, are activated without receiving a PDCCH indicating a downlink assignment or uplink grant. The activated BWP for the serving cell is indicated by RRC or PDCCH. For unpaired spectrum, the DL BWP is paired with the UL BWP, and the BWP conversion is common to both UL and DL. When the BWP inactivity timer expires, the UE converts the activated DL BWP to the default DL BWP or the initial DL BWP (if the default DL BWP is not configured).

[0059] In the fifth generation wireless communication system (also known as New Radio, NR), for UE in Radio Resource Control (RRC) CONNECTED, network-controlled cell-level mobility is supported. The typical process of cell-level mobility as described in TS 38.300 is as follows:

[0060] 1. The source gNB configures the UE measurement procedure and UE reporting according to the measurement configuration.

[0061] 2. The source gNB decides to hand over the UE based on the Measurement Report and RRM information.

[0062] 3. The source gNB issues a Handover Request message to the target gNB, passing a transparent RRC container with information to prepare for the handover on the target side. This information includes at least the target cell ID, KgNB*, the C-RNTI of the UE in the source gNB, the RRM configuration including the UE inactivity time, the basic AS-configuration including antenna information and DL carrier frequency, the current QoS flow to DRB mapping rule applied to the UE, SIB1 from the source gNB, UE capabilities for different RATs, PDU session related information, and can include UE reported measurement information including beam related information (if available). PDU session related information includes slice information (if supported) and (multiple) QoS flow level QoS profiles.

[0063] 4. Admission control may be performed by the target gNB. If slice information is transmitted to the target gNB, slice-aware admission control shall be performed. If a PDU session is associated with an unsupported slice, the target gNB shall reject such a PDU session.

[0064] 5. The target gNB prepares for handover with L1 / L2 and transmits a HANDOVER REQUEST ACKNOWLEDGE to the source gNB, which includes a transparent container to be transmitted to the UE as an RRC message to perform the handover.

[0065] 6. The source gNB triggers Uu handover by transmitting an RRCReconfiguration message to the UE, which contains information for accessing the target cell: at least the target cell ID, the new C-RNTI, the target gNB security algorithm identifier for the selected security algorithm. It can also include a set of dedicated RACH resources, an association between RACH resources and (multiple) SSBs, an association between RACH resources and UE-specific (multiple) CSI-RS configurations, common RACH resources, and system information of the target cell.

[0066] 7. The source gNB transmits the SN STATUS TRANSFER message to the target gNB.

[0067] 8. After DL synchronization, the UE synchronizes to the target cell and performs the random access procedure for UL synchronization. The UE completes the RRC handover procedure by transmitting an RRCReconfigurationComplete message to the target gNB.

[0068] 9. The target gNB sends a PATH SWITCH REQUEST message to the AMF to trigger the 5GC to switch the DL data path towards the target gNB and establish the NG-C interface instance towards the target gNB.

[0069] 10.5GC switches the DL data path towards the target gNB. The UPF transmits one or more “end marker” packets per PDU session / tunnel on the old path to the source gNB and can then release any U-Plane / TNL resources towards the source gNB.

[0070] 11.AMF acknowledges the PATH SWITCH REQUEST message with a PATH SWITCH REQUEST ACKNOWLEDGE message.

[0071] 12. Upon receiving the PATH SWITCH REQUEST ACKNOWLEDGE message from the AMF, the target gNB transmits UECONTEXT RELEASE to inform the source gNB about the success of the handover. The source gNB may then release the radio and C-plane related resources associated with the UE context. Any ongoing data forwarding may continue.

[0072] In order to reduce handover delay, RACH-free handover is being studied. In the case of RACH-free handover, the UE may not perform random access with the target cell. The handover command (i.e., RRCReconfiguration, where the CellGroupConfig IE in the RRCReconfiguration message contains spCellConfig with reconfigurationWithSync) may indicate whether the UE should skip random access with the target cell. For UL transmission in the target cell, the handover command also indicates whether the timing advance (TA) of the source cell is applied or the TA is equal to zero. The handover command may optionally provide a pre-allocated UL grant for sending an RRCReconfigurationComplete message and / or UL data. NR supports high frequency bands (between 24250MHz and 52600MHz) (also known as FR2 bands) and lower frequency bands (between 410MHz and 7125MHz) (also known as FR1 bands). At high frequencies, beamforming may be necessary. In the current handover process, the initial beam alignment between the UE and the target cell occurs via a random access process. In the case of RACH-free switching, for beam alignment, the pre-allocated UL grant signaled in the switching command (i.e., RRCReconfiguration, where the CellGroupConfig IE in the RRCReconfiguration message contains spCellConfig with reconfigurationWithSync) can be associated with one or more synchronization signal blocks, i.e., (multiple) SSBs / channel state information reference signals (i.e., (multiple) CSI RSs transmitted by the gNB). Each SSB / CSI-RS is identified by an SSB ID / CSI-RS ID, respectively. The UE is able to select a suitable SSB / CSI RS (wherein the SSB / CSI RS is suitable if the SS-RSRP / CSI-RSRP measured by the UE for the SSB / CSI-RS is above a configured threshold), and then send a MAC PDU in the UL grant corresponding to the selected SSB / CSI RS. The method determines which UL grant among the pre-allocated UL grants is associated with which SSB / CSI RS and what is the HARQ process ID corresponding to each UL grant among the pre-allocated UL grants.

[0073] In NR, the network may signal the configured UL grant by sending an RRCReconfiguration message including the ConfiguredGrantConfig IE. The UE may determine the HARQ process ID corresponding to the configured UL grant starting at "CURRENT_symbol" as follows:

[0074] HARQ process ID = [floor (CURRENT_symbol / cycle)] modulo nrofHARQ-Processes

[0075] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0076] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0077] Period (in symbols) is the period of the UL grant configured via ConfiguredGrantConfig. ConfiguredGrantConfig is signaled in the RRCReconfiguration message.

[0078] SFN is the system frame number that allocates the UL grant for this configuration

[0079] The timeslot number is the starting timeslot of the UL grant for this configuration

[0080] The symbol number is the starting symbol of the UL authorization for this configuration

[0081] Signal nrofHARQ-Processes in ConfiguredGrantConfig

[0082] In case of a bundled UL grant, CURRENT_symbol refers to the symbol index of the first transmission opportunity where the repetitive bundling occurs.

[0083] Figure 1 is an example illustration of the mapping between HARQ process IDs and configured UL grants based on the above method. In this example, nrofHARQ-Processes is 2. HARQ process IDs are sequentially assigned to UL grants every "N" cycles, where the first cycle starts at SFN 0 and N is equal to nrofHARQ-Processes.

[0084] According to an embodiment of the present disclosure, a method for mapping between configured UL grant, SSB / CSI-RS and HARQ process ID in case of RACH reconfiguration without synchronization in handover / reconfigurationWithSync / reconfiguration procedure is provided.

[0085] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. These methods can also be applied to situations other than the handover / reconfigurationWithSync / reconfiguration process.

[0086] Figure 2 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0087] refer to Figure 2 , the network (i.e., gNB) may signal (e.g., in a reconfiguration message or system information or connection release message) a configured grant configuration and a list of SSB / CSI RSs associated with the configured grant configuration (SSBID or CSI RS ID or TCI state ID is included in the list). In this method, the SSB / CSI RSs in the SSB / CSI RS list associated with the configured grant configuration are sequentially associated to the UL grant every "N" periods, where the first period starts from SFN 0 and N is equal to the number of SSB / CSI RSs in the list. In the example, nrofHARQ-Processes is 2 and the number of SSB / CSI-RSs associated with the configured grant is 2.

[0088] Figure 3 is a flowchart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0089] In operation S310, the UE may receive an RRCReconfiguration message from the gNB. The spCellConfig in the RRCReconfiguration message may include reconfigurationWithSync. The information included in the reconfigurationWithSync IE (e.g., an indication of skipping RACH) indicates that the UE will skip RACH towards the target cell. The RRCReconfiguration message may include a pre-allocated UL grant configuration (a parameter indicating that UL grants occur periodically). The configuration may be provided for at least the UL BWP indicated by firstActiveUplinkBWP-Id. The RRCReconfiguration message may also include a list (associationList) of (multiple) SSB / CSI-RS associated with the pre-allocated or configured UL grant. In an alternative embodiment, the above information for the pre-allocated / configured UL grant configuration sent in the RRCReconfiguration message can be sent by the gNB in ​​a connection release message or in a system information message to use the configured UL grant in an idle / inactive state. The pre-allocated / configured UL grant configuration in the idle / inactive state is used for the initially activated UL BWP, or the UL BWP may also be indicated. In operation S320, the UE may select an SSB / CSI-RS from among (multiple) SSB / CSI RSs associated with the pre-allocated or configured UL grants. Before selecting the SSB / CSI-RS, an SSB / CSI RS transmitted by a cell (e.g., a target cell in the case of a handover) may be received at the UE.

[0090] In operation S330, the UE may determine a configured UL grant corresponding to the selected SSB / CSI-RS. The configured UL grant may be associated with the SSB / CSI-RS in the "index+1" row in the list of associated SSB / CSI RS. If index=[floor(CURRENT_symbol / period)] modulo N1,

[0091] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0092] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to the SCS and is predefined for each SCS.

[0093] • Period (in symbols) is the period of configuring UL grants and is signaled in the RRCReconfiguration message or System Information or Connection Release message.

[0094] SFN is the system frame number for the UL grant allocation

[0095] The timeslot number is the starting timeslot of the configured UL grant

[0096] The symbol number is the starting symbol of the configured UL authorization

[0097] nrofHARQ-Processes is signaled in the RRCReconfiguration message or the System Information or Connection Release message.

[0098] N1 = Number of SSB / CSI-RS associated with the configured UL grant

[0099] In operation S340, the UE may determine the HARQ process ID for the selected configured UL grant as follows: HARQ process ID = [floor (CURRENT_symbol / (period * N1))] modulonrofHARQ-Processes

[0100] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0101] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0102] • Period (in symbols) is the period of configuring UL grants and is signaled in the RRCReconfiguration message or System Information or Connection Release message.

[0103] SFN is the system frame number for the UL grant allocation

[0104] The timeslot number is the starting timeslot of the configured UL grant

[0105] The symbol number is the starting symbol of the configured UL authorization

[0106] Signal nrofHARQ-Processes in RRCReconfiguration message or System Information or Connection Release message

[0107] N1 = Number of SSB / CSI-RS associated with the configured UL grant

[0108] In operation S350, the UE may send a reconfiguration complete message or a UL MAC PDU in a determined UL grant corresponding to the selected SSB / CSI RS using the determined HARQ process.

[0109] Figure 4 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0110] refer to Figure 4 , the network may signal (e.g., in a reconfiguration message or a system information message or a connection release message) a configured grant configuration and a list of SSB / CSI RSs associated with the configured grant configuration (SSB ID or CSI RS ID or TCI state ID is included in the list). In the example, nrofHARQ-Processes is 2, and the number of SSB / CSI-RSs associated with the configured grant is 2.

[0111] Figure 5 is a flowchart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0112] In operation S510, the UE may receive an RRCReconfiguration message from the gNB. The spCellConfig in the RRCReconfiguration message may include reconfigurationWithSync. The information included in the reconfigurationWithSync IE (e.g., an indication of skipping RACH) indicates that the UE will skip RACH towards the target cell. The RRCReconfiguration message may include a pre-allocated UL grant configuration (a parameter indicating that UL grants occur periodically). The configuration may be provided for at least the UL BWP indicated by firstActiveUplinkBWP-Id. The RRCReconfiguration message may also include a list (associationList) of (multiple) SSB / CSI-RS associated with the pre-allocated or configured UL grant. In an alternative embodiment, the above information for the pre-allocated / configured UL grant configuration sent in the RRCReconfiguration message may be sent by the gNB in ​​a connection release message or in a system information message to use the configured UL grant in an idle / inactive state. The pre-allocated / configured UL grant configuration in the idle / inactive state is used to initially activate the UL BWP, or the UL BWP may also be indicated.

[0113] In operation S520, the UE may select an SSB / CSI-RS from among (multiple) SSB / CSI-RS associated with the pre-allocated or configured UL grant. Before selecting the SSB / CSI-RS, an SSB / CSI RS transmitted by a cell (e.g., a target cell in the case of handover) may be received at the UE.

[0114] In operation S530, the UE may determine a configured UL grant corresponding to the selected SSB / CSI-RS. If index=[floor(CURRENT_symbol / (period*N1))] modulo N1, the configured UL grant may be associated with the SSB / CSI-RS in the "index+1" row in the list of associated SSB / CSI RSs, where

[0115] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0116] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0117] • Period (in symbols) is the period of configuring UL grants and is signaled in the RRCReconfiguration message or System Information or Connection Release message.

[0118] SFN is the system frame number for the UL grant allocation

[0119] The timeslot number is the starting timeslot of the configured UL grant

[0120] The symbol number is the starting symbol of the configured UL authorization

[0121] Signal nrofHARQ-Processes in RRCReconfiguration message or System Information or Connection Release message

[0122] N1 = Number of SSB / CSI-RS associated with the configured UL grant

[0123] In operation S540, the UE may determine a HARQ process ID for the selected configured UL grant as follows:

[0124] HARQ process ID = [floor (CURRENT_symbol / (period))] modulo nrofHARQ-Processes

[0125] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0126] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0127] • Period (in symbols) is the period of configuring UL grants and is signaled in the RRCReconfiguration message or System Information or Connection Release message.

[0128] SFN is the system frame number for the UL grant allocation

[0129] The timeslot number is the starting timeslot of the configured UL grant

[0130] The symbol number is the starting symbol of the configured UL authorization

[0131] Signal nrofHARQ-Processes in RRCReconfiguration message or System Information or Connection Release message

[0132] In operation S550, the UE may send a reconfiguration complete message or a UL MAC PDU in the determined UL grant corresponding to the selected SSB / CSI RS using the determined HARQ process.

[0133] Figure 6 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0134] refer to Figure 6 , the network may signal (e.g., in a reconfiguration message or a system information message or a connection release message) one or more configured grant configurations. Each configured grant configuration may be associated with (multiple) SSB / CSI RS (indicating (multiple) SSB IDs or (multiple) CSI RS IDs or (multiple) TCI state IDs). In this example, there are two configured grant configurations, where configuration 1 is associated with SSB ID X and configuration 2 is associated with SSB ID Y. All UL grants configured via configuration 1 belong to SSB X. All UL grants configured via configuration 1 belong to SSB Y. The HARQ process ID corresponding to each UL grant corresponding to the configuration may be determined as in an existing system or as explained above.

[0135] Figure 7 is a flowchart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0136] In operation S710, the UE may receive an RRCReconfiguration message from the gNB. The spCellConfig in the RRCReconfiguration message may include reconfigurationWithSync. The information included in the reconfigurationWithSync IE (e.g., an indication of skipping RACH) indicates that the UE will skip RACH towards the target cell. The RRCReconfiguration message may include one or more pre-allocated / configured UL grant configurations (parameters indicating that UL grants occur periodically). These configurations may be provided for at least the UL BWP indicated by firstActiveUplinkBWP-Id. Each pre-allocated / configured UL grant configuration may be associated with (multiple) SSB / CSI RS (the (multiple) SSB IDs or (multiple) CSI RS IDs or (multiple) TCI state IDs of (multiple) SSB / CSI RS are indicated / signaled by the gNB). In an alternative embodiment, the above information for the pre-allocated / configured UL grant configuration sent in the RRCReconfiguration message may be sent by the gNB in ​​a connection release message or in a system information message to use the configured UL grant in an idle / inactive state. A pre-allocated / configured UL grant in an idle / inactive state configures a UL BWP for initial activation or may also indicate a UL BWP.

[0137] In operation S720, the UE may select an SSB / CSI-RS from among (a plurality of) SSB / CSIRS associated with a pre-allocated or configured UL grant configuration. For example, if there are two configured grant configurations and configuration 1 is associated with SSB X and configuration 2 is associated with SSB Y, the UE selects an SSB from SSB X and SSB Y. Before selecting the SSB / CSI-RS, an SSB / CSI RS transmitted by a cell (e.g., a target cell in the case of handover) may be received at the UE.

[0138] In operation S730, the UE may determine a UL grant configuration associated with the selected SSB / CSI-RS. The UE may determine a UL grant from the selected UL grant configuration.

[0139] In operation S740, the UE may determine a HARQ process ID for a UL grant of a configuration determined from the selected configuration as follows:

[0140] HARQ process ID = [floor (CURRENT_symbol / (period))] modulo nrofHARQ-Processes

[0141] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0142] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0143] • Period (in symbols) is the period for configuring UL grants in the selected UL grant configuration.

[0144] SFN is the system frame number for the UL grant allocation

[0145] The timeslot number is the starting timeslot of the configured UL grant

[0146] The symbol number is the starting symbol of the configured UL authorization

[0147] Signaling nrofHARQ-Processes in the selected UL grant configuration

[0148] In operation S750, the UE may send a reconfiguration complete message or a UL MAC PDU in the determined UL grant corresponding to the selected SSB / CSI RS using the determined HARQ process.

[0149] Figure 8 is a diagram illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0150] refer to Figure 8 , the network may signal (e.g., in a reconfiguration message or a system information message or a connection release message) one or more configured grant configurations. Each configured grant configuration is associated with (multiple) SSB / CSI RS (indicating (multiple) SSB IDs or (multiple) CSI RS IDs or (multiple) TCI state IDs). Figure 8is an example illustration of the mapping between HARQ process IDs, SSB / CSI-RS, and configured UL grants. In the example, there are two configured grant configurations, where configuration 1 is associated with SSB ID X and configuration 2 is associated with SSB ID Y. All UL grants configured via configuration 1 belong to SSB X. All UL grants configured via configuration 1 belong to SSB Y. The starting HARQ process ID for configuration 1 is 0. The starting HARQ process ID for configuration 2 is "0+nrofHARQ-Processes for configuration 1". The starting HARQ process ID for the i-th configuration is "0+nrofHARQ-Processes for configuration 1+...+nrofHARQ-Processes for configuration 'i-1'".

[0151] Fig. 9 is a flowchart illustrating a method of mapping SSB / CSI-RS, HARQ process ID, and configured UL grant according to an embodiment of the present disclosure.

[0152] In operation S910, the UE may receive an RRCReconfiguration message from the gNB. The spCellConfig in the RRCReconfiguration message may include reconfigurationWithSync. The information included in the reconfigurationWithSync IE (e.g., an indication of skipping RACH) indicates that the UE will skip RACH towards the target cell. The RRCReconfiguration message may include one or more pre-allocated / configured UL grant configurations (parameters indicating that UL grants occur periodically). These configurations are provided for at least the UL BWP indicated by firstActiveUplinkBWP-Id. Each pre-allocated / configured UL grant configuration is associated with (multiple) SSB / CSI RS (the (multiple) SSB IDs or (multiple) CSI RS IDs or (multiple) TCI state IDs of the associated (multiple) SSB / CSI RS are indicated / signaled by the gNB). In an alternative embodiment, the above information for the pre-allocated / configured UL grant configuration sent in the RRCReconfiguration message may be sent by the gNB in ​​a connection release message or in a system information message to use the configured UL grant in an idle / inactive state. A pre-allocated / configured UL grant in an idle / inactive state configures a UL BWP for initial activation, or may also indicate a UL BWP.

[0153] In operation S920, the UE may select an SSB / CSI-RS from among (a plurality of) SSB / CSIRS associated with a pre-allocated or configured UL grant configuration. For example, if there are two configured grant configurations and configuration 1 is associated with SSB X and configuration 2 is associated with SSB Y, the UE selects an SSB from SSB X and SSB Y. Before selecting the SSB / CSI-RS, an SSB / CSI RS transmitted by a cell (e.g., a target cell in the case of handover) may be received at the UE.

[0154] In operation S930, the UE may determine a UL grant configuration associated with the selected SSB / CSI-RS. The UE selects a UL grant from the selected UL grant configuration.

[0155] In operation S940, the UE may determine a HARQ process ID for a UL grant of a configuration selected from among the selected configurations as follows:

[0156] HARQ process ID = offset + [floor (CURRENT_symbol / (period))] modulonrofHARQ-Processes

[0157] - Wherein, CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + number of slots in a frame × numberOfSymbolsPerSlot + number of symbols in a slot)

[0158] numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. numberOfSlotsPerFrame is specific to an SCS and is predefined for each SCS.

[0159] • Period (in symbols) is the period for configuring UL grants in the selected UL grant configuration.

[0160] SFN is the system frame number for the UL grant allocation

[0161] The timeslot number is the starting timeslot of the configured UL grant

[0162] The symbol number is the starting symbol of the configured UL authorization

[0163] Signaling nrofHARQ-Processes in the selected UL grant configuration

[0164] - The offset for the i-th UL grant configuration is 0 + nrofHARQ-Processes for configuration 1 + nrofHARQ-Processes for configuration 1 + ... + nrofHARQ-Processes for configuration "i-1"

[0165] • In an alternative embodiment, an "offset" can be signaled in each configured authorization configuration. If an "offset" is not signaled for a configured authorization configuration, it is assumed to be zero.

[0166] In operation S950, the UE may then send a reconfiguration complete message or a UL MAC PDU in the selected UL grant corresponding to the selected SSB / CSI RS using the selected HARQ process.

[0167] According to another embodiment, the UE may receive an RRCReconfiguration message from the gNB. The spCellConfig in the RRCReconfiguration message may include reconfigurationWithSync. The information in the reconfigurationWithSync IE (e.g., an indication of skipping RACH) indicates that the UE will skip RACH towards the target cell. The RRCReconfiguration message includes the configured UL grant configuration (parameters indicating that UL grants occur periodically). These configurations are provided at least for the UL BWP indicated by firstActiveUplinkBWP-Id. In an alternative embodiment, the above information for the pre-allocated / configured UL grant configuration sent in the RRCReconfiguration message may be sent by the gNB in ​​a connection release message or in a system information message to use the configured UL grant in an idle / inactive state. The pre-allocated / configured UL grant configuration in the idle / inactive state is used for the initially activated UL BWP, or the UL BWP may also be indicated.

[0168] The UE may identify whether it can apply the UL grant indicated in the configured UL grant configuration before the RACH-free reconfiguration with synchronization is completed, as described below.

[0169] Option 1: Separately configure the UL grant configuration for RACH reconfiguration without synchronization, for example, using the new IE ConfiguredGrantConfigRACHless. If this IE is included in the RRCReconfiguration message, the UE uses the UL grant indicated in this IE for RACH reconfiguration without synchronization.

[0170] Option 2: Do not separately configure the UL grant configuration for the configuration without RACH reconfiguration with synchronization. If the grant configuration includes the associated SSB / CSI-RS, or if the list of SSB / CSI-RS associated with the grant configuration is signaled, the UE uses the UL grant indicated in the grant configuration for the configuration without RACH reconfiguration with synchronization.

[0171] Fig.10 is a flowchart of a method for mapping SSB / CSI-RS, HARQ process ID, and configured UL grant at a UE according to an embodiment of the present disclosure.

[0172] In operation S1010, the UE may receive uplink (UL) grant configuration information via an RRC reconfiguration message. The UL grant configuration information may include at least one of a RACH skip indication, a pre-allocated UL grant configuration, and a list associated with the pre-allocated UL grant.

[0173] In operation S1020, the UE may select an SSB / CSI-RS from a plurality of SSB / CSI-RS included in the UL grant information. The UE may obtain a list indicating SSB / CSI RS for a plurality of UL grant configurations from the UL grant configuration information. The SSB / CSI-RS is selected according to at least one of the foregoing embodiments or a combination of the foregoing embodiments.

[0174] In operation S1030, the UE may determine a UL grant corresponding to the selected SSB / CSI-RS and a HARQ process corresponding to the UL grant based on each of the plurality of UL grant configurations. The UL grant is selected according to at least one of the aforementioned embodiments or a combination of the aforementioned embodiments.

[0175] In operation S1040, the UE may control the transceiver to send a reconfiguration complete message or a UL MAC PDU in the determined UL grant corresponding to the selected SSB / CSI RS using the HARQ process. The HARQ process is determined according to at least one of the aforementioned embodiments or a combination of the aforementioned embodiments.

[0176] Fig.11 Detailed description is a flowchart of a method for mapping SSB / CSI-RS, HARQ process ID, and configured UL grant at a base station according to an embodiment of the present disclosure.

[0177] In operation S1110, the base station may transmit uplink (UL) grant configuration information via an RRC reconfiguration message. The UL grant configuration information may include at least one of a RACH skip indication, a pre-allocated UL grant configuration, and a list associated with the pre-allocated UL grant.

[0178] In operation S1120, the base station may receive a reconfiguration complete message or a UL MAC PDU in a UL grant corresponding to the SSB / CSI RS selected at the UE from the UE using a HARQ process, select an SSB / CSI RS from a plurality of SSB / CSI RSs included in the UL grant information, and determine a UL grant corresponding to the selected SSB / CSI RS and a HARQ process corresponding to the UL grant based on the UL grant information. Fig.12 is a diagram illustrating a UE 1200 according to an embodiment of the present disclosure.

[0179] Reference Fig.12 UE 1200 may include a processor 1210, a transceiver 1220, and a memory 1230. However, not all of the components shown are required. UE 1200 may include a processor 1210, a transceiver 1220, and a memory 1230. Fig.12 In addition, according to another embodiment, the processor 1210, the transceiver 1220, and the memory 1230 may be implemented as a single chip.

[0180] The above-mentioned components will now be described in detail.

[0181] The processor 1210 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of the UE 1200 may be implemented by the processor 1210 .

[0182] The processor 1210 may control the transceiver 1220 to receive uplink (UL) grant configuration information via an RRC reconfiguration message. The processor 1210 may select an SSB / CSI RS from among a plurality of SSB / CSI RSs included in the UL grant information. The processor 1210 may determine a UL grant corresponding to the selected SSB / CSI RS and a HARQ process corresponding to the UL grant based on the UL grant information. The processor 1210 may control the transceiver 1220 to send a reconfiguration complete message or a UL MAC PDU in the determined UL grant corresponding to the selected SSB / CSI RS using the HARQ process.

[0183] The transceiver 1220 may be connected to the processor 1210 and transmit and / or receive a signal. The signal may include an RRC reconfiguration message or UL data. In addition, the transceiver 1220 may receive a signal through a wireless channel and output the signal to the processor 1210. The transceiver 1220 may transmit a signal output from the processor 1210 through a wireless channel.

[0184] The memory 1230 may store control information or data included in a signal obtained by the UE 1200. The memory 1230 may be connected to the processor 1210 and store at least one instruction and protocol and parameter for the proposed function, process and / or method. The memory 1230 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices.

[0185] Fig.13 is a diagram illustrating a base station 1300 according to an embodiment of the present disclosure.

[0186] refer to Fig.13 , the base station 1300 may include a processor 1310, a transceiver 1320, and a memory 1330. However, all the components shown are not required. The base station 1300 may be composed of Fig.13 In addition, according to another embodiment, the processor 1310, the transceiver 1320, and the memory 1330 may be implemented as a single chip.

[0187] The above-mentioned components will now be described in detail.

[0188] The processor 1310 may include one or more processors or other processing devices that control the proposed functions, processes and / or methods. The operations of the base station 1300 may be implemented by the processor 1310 .

[0189] The processor 1310 may control the transceiver 1320 to transmit uplink (UL) grant configuration information via an RRC reconfiguration message. The processor 1310 may control the transceiver 1320 to receive a reconfiguration complete message in a UL grant corresponding to an SSB / CSI RS selected at the UE from a user equipment (UE) using a HARQ process.

[0190] The transceiver 1320 may be connected to the processor 1310 and transmit and / or receive signals. The signals may include control information and data. In addition, the transceiver 1320 may receive signals through a wireless channel and output the signals to the processor 1310. The transceiver 1320 may transmit signals output from the processor 1310 through a wireless channel.

[0191] The memory 1330 may store control information or data included in the signal obtained by the base station 1300. The memory 1330 may be connected to the processor 1310 and store at least one instruction and protocol and parameters for the proposed function, process and / or method. The memory 1330 may include a read-only memory (ROM) and / or a random access memory (RAM) and / or a hard disk and / or a CD-ROM and / or a DVD and / or other storage devices. At least some of the example embodiments described herein may be constructed in part or in whole using specialized dedicated hardware. Terms such as "component", "module" or "unit" used herein may include but are not limited to hardware devices that perform specific tasks or provide related functions, such as circuits in the form of discrete or integrated components, field programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to run on one or more processors. In some embodiments, as an example, these functional elements may include components, such as software components, object-oriented software components, class components and task components, processing, functions, attributes, processes, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays and variables. Although exemplary embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it should be understood that the described features may be combined in any suitable combination. In particular, the features of any one exemplary embodiment may be appropriately combined with the features of any other embodiment, unless this combination is mutually exclusive. Throughout the specification, the term "include" or "comprise" means including specified (multiple) components, but does not exclude the presence of other components.

[0192] Attention is paid to all papers and documents related to the present application filed concurrently with or before the present specification, which are disclosed to the public together with the present specification, and the contents of all these papers and documents are incorporated herein by reference.

[0193] All features disclosed in this specification (including any accompanying claims, abstract and drawings) and / or all steps of any method or process so disclosed may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive.

[0194] Unless expressly stated otherwise, each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose. Therefore, unless expressly stated otherwise, each feature disclosed is only an example of a general series of equivalent or similar features.

[0195] The present disclosure is not limited to the details of the foregoing embodiment(s). The present disclosure extends to any novel one or any novel combination of features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one or any novel combination of steps of any method or process so disclosed.

[0196] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for performing communication in a wireless communication system by a user equipment UE, the method comprising: Receiving uplink UL grant configuration information via a radio resource control RRC release message; Selecting an SSB from among at least one synchronization signal block SSB identified based on the UL grant configuration information; determining a UL grant corresponding to the selected SSB; Determining a hybrid automatic repeat request HARQ process corresponding to the UL grant based on the UL grant configuration information; and In the RRC INACTIVE state, a UL media access control protocol data unit MAC PDU is sent based on the determined UL grant using the HARQ process.

2. The method according to claim 1, wherein: Confirming UL authorization includes: identifying, based on the UL grant configuration information, a period for configuring one or more UL grants and a number of the at least one SSB associated with the one or more UL grants; and A UL grant is determined based on the current symbol using the identified period and the identified number of the at least one SSB.

3. The method according to claim 1, wherein: Selecting the SSB includes: obtaining, from the UL grant configuration information, a list indicating the at least one SSB for one or more UL grant configurations; and Each SSB is selected for each of the one or more UL grant configurations.

4. The method according to claim 3, wherein: Determining the HARQ process includes: identifying an offset value for each of the one or more UL grant configurations; and A HARQ process corresponding to the UL grant is determined based on the identified offset value.

5. A method for performing communication by a base station in a wireless communication system, the method comprising: Sending uplink UL grant configuration information via a radio resource control RRC release message; as well as receiving a UL medium access control protocol data unit MAC PDU based on a UL grant from a user equipment UE in an RRC INACTIVE state using a hybrid automatic repeat request HARQ process, in: An SSB among at least one synchronization signal block SSB identified based on the UL grant configuration information is selected at the UE, The UL grant corresponding to the selected SSB is determined, and The HARQ process corresponding to the UL grant is determined based on the UL grant configuration information.

6. A user equipment UE for performing communication in a wireless communication system, the UE comprising: Transceiver; as well as a processor coupled to the transceiver and configured to: receiving uplink UL grant configuration information via a radio resource control RRC release message, selecting an SSB among at least one synchronization signal block SSB identified in the UL grant configuration information, determining a UL grant corresponding to the selected SSB, determining a hybrid automatic repeat request HARQ process corresponding to the UL grant based on the UL grant configuration information, and In the RRC INACTIVE state, a UL media access control protocol data unit MAC PDU is sent based on the determined UL grant using the HARQ process.

7. The UE according to claim 6, wherein: The processor is further configured to: identifying, based on the UL grant configuration information, a period for configuring one or more UL grants and a number of the at least one SSB associated with the one or more UL grants, and A UL grant is determined based on the current symbol using the identified period and the identified number of the at least one SSB.

8. The UE according to claim 6, wherein: The processor is further configured to: obtaining, from the UL grant configuration information, a list indicating the at least one SSB for one or more UL grant configurations, and Each SSB is selected for each of the one or more UL grant configurations.

9. The UE according to claim 8, wherein: The processor is further configured to: identifying an offset value for each of the one or more UL grant configurations; and A HARQ process corresponding to the UL grant is determined based on the identified offset value.

10. A base station for performing communication in a wireless communication system, the base station comprising: Transceiver; as well as a processor coupled to the transceiver and configured to: Sending uplink UL grant configuration information via a radio resource control RRC release message, and receiving a UL medium access control protocol data unit MAC PDU based on a UL grant from a user equipment UE in an RRC INACTIVE state using a hybrid automatic repeat request HARQ process, in: An SSB among at least one synchronization signal block SSB identified based on the UL grant configuration information is selected at the UE, The UL grant corresponding to the selected SSB is determined, and The HARQ process corresponding to the UL grant is determined based on the UL grant configuration information.

11. The base station according to claim 10, wherein: configuring a period of one or more UL grants and a number of the at least one SSB associated with the one or more UL grants to be identified based on the UL grant configuration information, and The UL grant is determined based on the current symbol using the identified period and the identified number of the at least one SSB.

12. The base station according to claim 10, wherein: indicating that the list of at least one SSB for one or more UL grant configurations is obtained from UL grant configuration information, and Each SSB of each UL grant configuration of the one or more UL grant configurations is selected.

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