Method and apparatus for processing system information request in a wireless communication system

Abstract

The present disclosure relates to a communication method and system for integrating a fifth generation (5G) communication system and Internet of Things (IoT) technology for supporting higher data rates than a fourth generation (4G) system. The present disclosure can be applied to smart services based on 5G communication technology and IoT-related technologies, such as smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, safety and security services. The present disclosure provides a method and apparatus for managing system information in a wireless communication system.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system. In particular, the present disclosure relates to an apparatus, method and system for managing system information in a radio resource control (RRC) connection state in a wireless communication system. Background Art

[0002] In order to meet the increased demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems". 5G communication systems are considered to be implemented in higher frequency (millimeter wave) 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 in 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, coordinated multi-points (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid FSK and QAM 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) as advanced access technologies.

[0003] The Internet, which is a human-centered connected network in which humans generate and consume information, is now developing towards 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. As IoT implementation requires 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 intelligent 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, health care, 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, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks (RANs) as an application of the above-mentioned big data processing technologies can also be considered as an example of the convergence between 5G technologies and IoT technologies.

[0005] Recently, there is a need to enhance current procedures for managing system information in next generation wireless communication systems. Summary of the invention

[0006] Technical issues

[0007] Aspects of the present disclosure at least address the above-mentioned problems and / or disadvantages and provide at least the following advantages. Therefore, one aspect of the present disclosure is to provide a communication method and system for converging a fifth generation (5G) communication system for supporting higher data rates beyond the fourth generation (4G).

[0008] Solution to the problem

[0009] According to one aspect of the present disclosure, a method performed by a terminal is provided. The method includes: when the terminal is in a radio resource control (RRC) connected state, receiving an RRC message including a system information block 1 (SIB1) and information associated with synchronization reconfiguration of a target special cell (SpCell); identifying that the terminal does not store a valid version of at least one required SIB based on SIB1; and after a random access procedure to the target SpCell is completed, sending a dedicated SIB request message for at least one required SIB to the target SpCell.

[0010] According to one aspect of the present disclosure, a method performed by a target SpCell is provided. The method includes: performing a random access procedure with a terminal in a radio resource control (RRC) connection state with a source SpCell; and receiving a dedicated system information block (SIB) request message for at least one required SIB from the terminal after the random access procedure is completed if the terminal does not store a valid version of at least one required SIB, wherein the random access procedure is performed if the terminal has received an RRC message including SIB1 and information associated with synchronization reconfiguration of the target SpCell from the source SpCell.

[0011] According to one aspect of the present disclosure, a terminal is provided. The terminal includes: a transceiver configured to send and receive signals; and a controller configured to: when the terminal is in a radio resource control (RRC) connected state, receive an RRC message including a system information block 1 (SIB1) and information associated with synchronization reconfiguration of a target special cell (SpCell), identify that the terminal does not store a valid version of at least one required SIB based on SIB1, and after a random access procedure to the target SpCell is completed, send a dedicated SIB request message for at least one required SIB to the target SpCell.

[0012] According to one aspect of the present disclosure, a target SpCell is provided. The target SpCell includes: a transceiver configured to send and receive signals; and a controller configured to: perform a random access procedure with a terminal in a radio resource control (RRC) connection state with a source SpCell, and, if the terminal does not store a valid version of at least one required SIB, after the random access procedure is completed, receive a dedicated system information block (SIB) request message for at least one required SIB from the terminal, wherein the random access procedure is performed if the terminal has received an RRC message including SIB1 and information associated with synchronization reconfiguration of the target SpCell from the source SpCell.

[0013] Advantageous Effects of the Invention

[0014] Therefore, one aspect of the present disclosure is to provide more and better applications and services in a wireless communication system by effectively managing system information in the wireless communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0016] Figure 1 A flowchart of processing SIB1 during a handover process according to an embodiment of the present disclosure is shown.

[0017] Figure 2 A flowchart of processing SIB1 received in the RRC connected state according to an embodiment of the present disclosure is shown.

[0018] Figure 3 A flowchart of processing SIB1 received in the RRC connected state according to another embodiment of the present disclosure is shown.

[0019] Figure 4 is a block diagram of a terminal according to an embodiment of the present disclosure.

[0020] Figure 5is a block diagram of a base station according to an embodiment of the present disclosure.

[0021] Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures. DETAILED DESCRIPTION

[0022] Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives refer to inclusion without limitation; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may refer to include, be included within, interconnected with, contain, be contained within, connect to or be connected with, be coupled to or be coupled with, be communicative with, cooperate with, interweave, juxtapose, be proximate, be incorporated into or be combined with, have, have the characteristics of, etc.; the term "controller" refers to any device, system, or part thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two of them. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether local or remote.

[0023] 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 embodied 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 parts thereof suitable for implementation with suitable computer-readable program codes. 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 disk (DVD) or any other type of memory. "Non-transient" computer-readable media do not include wired, wireless, optical or other communication links that transmit transient electrical signals or other signals. Non-transient 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 memory devices.

[0024] Definitions for certain words and phrases are provided in 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.

[0025] Discussed below Figures 1 to 5The various embodiments used to describe the principles of the present disclosure in this patent document are merely exemplary and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0026] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in understanding, but these are to be regarded as exemplary only. Therefore, it will be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures may be omitted for clarity and conciseness.

[0027] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0028] It should be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0029] The term "substantially" means that the recited characteristics, parameters or values ​​need not be achieved precisely, but deviations or changes including, for example, tolerances, measurement errors, measurement precision limitations and other factors known to those skilled in the art may occur in amounts that do not eliminate the effect that the characteristic is intended to provide.

[0030] Those skilled in the art know that the blocks of the flowchart (or sequence diagram) and the combination of the flowchart can be represented and executed by computer program instructions. These computer program instructions can be loaded on a processor of a general-purpose computer, a special-purpose computer, or a programmable data processing device. When the loaded program instructions are executed by the processor, they create a device for performing the functions described in the flowchart. Because the computer program instructions can be stored in a computer-readable memory available in a special-purpose computer or a programmable data processing device, it is also possible to create an article that performs the functions described in the flowchart. Because the computer program instructions can be loaded on a computer or a programmable data processing device, when executed as a process, they can perform the operations of the functions described in the flowchart.

[0031] The block of flow chart can correspond to a module, a fragment or a code containing one or more executable instructions for implementing one or more logical functions, or can correspond to a part thereof. In some cases, the functions described by the block can be performed in an order different from the listed order. For example, two blocks listed in order can be performed simultaneously or in reverse order.

[0032] In this specification, the words "unit", "module", etc. may refer to software components or hardware components, such as field programmable gate arrays (FPGAs) or application specific integrated circuits (ASICs) that can perform functions or operations. However, "units", etc. are not limited to hardware or software. Units, etc. may be configured to reside in an addressable storage medium or drive one or more processors. Units, etc. may refer to software components, object-oriented software components, class components, task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcodes, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by components and units may be combinations of smaller components and units, and may be combined with other components and units to form larger components and units. Components and units may be configured to drive devices or one or more processors in a secure multimedia card.

[0033] Prior to the detailed description, terms or definitions necessary for understanding the present disclosure are described. However, these terms should be interpreted in a non-restrictive manner.

[0034] A “base station (BS)” is an entity that communicates with a user equipment (UE) and may be referred to as a BS, a base transceiver station (BTS), a Node B (NB), an evolved NB (eNB), an access point (AP), a 5GNB (5GNB), or a gNB (next generation Node B).

[0035] A “UE” is an entity communicating with a BS and may be referred to as a UE, a device, a mobile station (MS), a mobile equipment (ME), or a terminal.

[0036] In recent years, several broadband wireless technologies have been developed to meet the growing number of broadband subscribers and to provide more and better applications and services. The second generation of wireless communication systems has been developed to provide voice services while ensuring the mobility of users. The third generation of wireless communication systems supports not only voice services but also data services. In recent years, the fourth generation of wireless communication systems has been developed to provide high-speed data services. However, at present, the fourth generation of wireless communication systems lacks resources to meet the growing demand for high-speed data services. Therefore, the fifth generation of wireless communication systems (also known as next generation radio or NR) is being developed to meet the growing demand for high-speed data services and support ultra-reliability and low-latency applications.

[0037] The fifth generation of wireless communication systems supports not only low frequency bands, but also higher frequency (millimeter wave) bands, such as 10 GHz to 100 GHz 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 MIMO, FD-MIMO, array antennas, analog beamforming, and massive antenna technologies are being considered in the design of the fifth generation of wireless communication systems. In addition, the fifth generation of wireless communication systems are expected to address different usage scenarios with completely different requirements in terms of data rate, latency, reliability, mobility, etc.

[0038] However, it is expected that the design of the air interface of the fifth generation wireless communication system will be flexible enough to serve UEs with completely different capabilities, depending on the use scenarios and market segments that the UE serves for the end customer. Several exemplary use scenarios that the fifth generation wireless communication system wireless system is expected to address are enhanced mobile broadband (eMBB), massive machine type communication (m-MTC), ultra-reliable low latency communication (URLL), etc. eMBB requirements such as tens of Gbps data rate, low latency, high mobility, etc. address the market segment representing traditional wireless broadband subscribers who need Internet connection anytime and anywhere. m-MTC requirements such as very high connection density, infrequent data transmission, very long battery life, low mobility address the market segment representing the Internet of Things (IoT) / Internet of Everything (IoE) where billions of devices are envisioned for connection. URLL requirements such as very low latency, very high reliability and variable mobility address the market segment representing industrial automation applications, vehicle-to-vehicle / vehicle-to-infrastructure communications that are considered one of the enablers of autonomous vehicles.

[0039] In the fifth generation wireless communication system operating in a higher frequency (e.g., millimeter wave) band, the UE and gNB communicate with each other using beamforming. Beamforming technology is used to mitigate propagation path loss and increase the propagation distance of higher frequency band communications. 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 various forms, such as a linear array, a planar array, and the like. The use of TX beamforming leads to an increase in signal directivity, 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.

[0040] The receiving end can perform beamforming on the RX signal by using an RX antenna array. RX beamforming increases the strength of the RX signal sent in a specific direction by allowing the propagation to be concentrated in a specific direction, and excludes the signal sent in a direction other than the specific direction from the RX signal, thereby providing the effect of blocking interference signals. By using beamforming technology, the transmitter can generate multiple transmit beam patterns in different directions. Each of these transmit beam patterns can also be referred to as a TX beam. Wireless communication systems operating at high frequencies use multiple narrow TX beams to transmit signals in a cell because each narrow TX beam provides coverage of a portion of the 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 generate multiple receive (RX) beam patterns in different directions. Each of these receive patterns can also be referred to as a receive (RX) beam.

[0041] The fifth generation wireless communication system supports independent operation mode and dual connection (DC). In DC, multiple Rx / Tx UEs 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 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 the UE under the radio resource control connection (RRC_CONNECTED) is configured to utilize radio resources provided by two different schedulers, where the two different schedulers are located in two different nodes connected via a non-ideal backhaul and providing Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (E-UTRA (ie, if the node is ng-eNB)) or NR access (ie, if the node is gNB). In NR, for UEs under RRC_CONNECTED that are not configured with carrier aggregation (CA) / DC, there is only one serving cell including a primary cell. For UEs in RRC_CONNECTED configured with CA / DC, the term "serving cell" is used to refer to a set of cells 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 primary cell (PCell) and optionally one or more secondary cells (SCells). In NR, the term secondary cell group (SCG) refers to a set of serving cells associated with a secondary node, including a primary SCG cell (PSCell) and optionally one or more SCells. In NR, PCell refers to a serving cell operating on the primary frequency in an MCG, where the UE either 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. PSCell refers to a serving cell in an SCG, where the UE performs random access when performing a synchronous reconfiguration 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.

[0042] In the fifth generation wireless communication system, the physical downlink control channel (PDCCH) is used to schedule downlink (DL) transmission on the physical downlink shared channel (PDSCH) and uplink (UL) transmission on the physical uplink shared channel (PUSCH), wherein the downlink control information (DCI) on the PDCCH includes: a downlink allocation including at least the modulation and coding format, resource allocation and hybrid automatic repeat request (ARQ) information related to the DL-SCH; and an uplink scheduling grant including at least the modulation and coding format, resource allocation and hybrid ARQ information related to the UL-SCH. In addition to scheduling, the PDCCH can be used to: activate and deactivate configured PUSCH transmissions with configured grants; activate and deactivate PDSCH semi-persistent transmissions; inform one or more UEs of the time slot format; inform one or more UEs of (multiple) physical resource blocks (PRBs) and (multiple) orthogonal frequency division multiplexing (OFDM) symbols, where the UE can assume that there are no transmissions for the UE; transmit transmit power command (TPC) commands for physical uplink control channel (PUCCH) and PUSCH; transmit one or more TPC commands for sounding reference signal (SRS) transmissions for one or more UEs; switch the active bandwidth part of the UE; initiate a random access procedure. The UE monitors the PDCCH candidate set 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 units Resource element groups (REGs) and control channel elements (CCEs) are defined in a CORESET, where each CCE includes a set of REGs. The control channel is formed by an aggregation of CCEs. Different code rates for control channels are achieved by aggregating different numbers of CCEs. Interleaved and non-interleaved CCE to REG mapping is supported in CORESET. Polarization codes are used for PDCCH. Each resource element group carrying PDCCH carries its own DMRS. Quadrature Phase Shift Keying (QPSK) modulation is used for PDCCH.

[0043] In the fifth generation wireless communication system, the GNB signals a list of search space configurations 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 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 pattern (Monitoring-symbols-PDCCH-within-slot) to determine the (multiple) PDCCH monitoring opportunities within a time slot. The PDCCH monitoring opportunity exists in time slots "x" to x+duration, where the time slot numbered "x" in the radio frame numbered "y" satisfies the following equation 1:

[0044] [Equation 1]

[0045] (y*(number of slots in a radio frame)+x-Monitoring-offset-PDCCH-slot)mod(Monitoring-periodicity-PDCCH-slot)=0;

[0046] The starting symbol of the PDCCH monitoring opportunity in each slot with a PDCCH monitoring opportunity is given by Monitoring-symbols-PDCCH-within-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. The GNB signals a list of CORESET configurations for each configured BWP, where each CORESET configuration is uniquely identified by an identifier. Note that the duration of each radio frame is 10ms. Radio frames are identified by radio frame numbers or system frame numbers. Each radio frame includes several slots, where the number of slots in a radio frame and the duration of the slots depend on the subcarrier spacing. In NR, the number of slots in a radio frame and the duration of the slots that depend on the radio frame are pre-defined for each supported subcarrier spacing (SCS). Each CORESET configuration is associated with a list of TCI (Transmission Configuration Indicator) states. Each TCI state configures a DL Reference Signal (RS) ID (SSB or Channel State Information RS (CSI-RS)). The TCI state list corresponding to the CORESET configuration is signaled by the gNB via RRC signaling. One TCI state in the TCI state list is activated by the gNB and indicated to the UE. The TCI state indication is used by the GNB to transmit the DL TX beam of the PDCCH in the PDCCH monitoring occasion of the search space (the DL TX beam is quasi-co-located (QCLed) with the SSB / CSI-RS of the TCI state).

[0047] In the fifth generation wireless communication system, bandwidth adaptation (BA) is supported. With BA, the reception and transmission 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 ordered to change (for example, shrink during low activity periods to save power); the position can be moved in the frequency domain (for example, to increase scheduling flexibility); and the subcarrier spacing can be ordered to change (for example, to allow different services). A subset of the total cell bandwidth of a cell is called a bandwidth part (BWP). BA is implemented by configuring the RRC-connected UE with (multiple) BWPs and telling the UE which configured BWP is currently the active BWP. When BA is configured, the UE only needs to monitor the PDCCH on one active BWP, that is, it does not need 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 one active UL and DL BWP at any point in time. BWP switching of the serving cell is used to activate an inactive BWP and deactivate an active BWP at one time. BWP switching is controlled by the PDCCH indicating a downlink allocation or uplink grant, by the bwp-InactivityTimer, by RRC signaling, or by the media access control (MAC) entity itself when initiating a 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 active without receiving a PDCCH indicating a downlink allocation or uplink grant. The active BWP of the serving cell is indicated by RRC or PDCCH. For unpaired spectrum, the DL BWP is paired with the UL BWP, and the BWP switching is common to both UL and DL. When the BWP inactivity timer expires, the UE switches to the active DL BWP, to the default DL BWP or the initial DL BWP (if the default DL BWP is not configured).

[0048] In 5G wireless communication systems, random access (RA) is supported. Random access (RA) is used to achieve UL time synchronization. RA is used by non-synchronized UEs in the RRC CONNECTED state during initial access, handover, RRC connection reestablishment process, scheduling request transmission, SCG addition / modification, beam failure recovery, and data or control information transmission in the UL. Several types of random access procedures are supported.

[0049] Contention-based random access (CBRA): This is also known as 4-step CBRA. In this type of random access, the UE first sends a random access preamble (also known as Msg1) and then waits for a random access response (RAR) in the RAR window. The RAR is also known as Msg2. The next generation Node B (gNB) sends the RAR on the PDSCH. The PDCCH that schedules the PDSCH carrying the RAR is addressed to the RA-Radio Network Temporary Identifier (RA-RNTI). The RA-RNTI identifies the time-frequency resources (also known as physical RA channel (PRACH) opportunity or PRACH transmission (TX) opportunity or RA channel (RACH) opportunity) in which the gNB detects the RA preamble. RA-RNTI is calculated as follows: RA-RNTI = 1 + s_id + 14 * t_id + 14 * 80 * f_id + 14 * 80 * 8 * ul_carrier_id, where s_id is the index of the first OFDM symbol of the PRACH opportunity in which the UE sent Msg1 (i.e., RA preamble); 0 ≤ s_id < 14; t_id is the index of the first time slot of the PRACH opportunity (0 ≤ t_id < 80); f_id is the index of the PRACH opportunity within the time slot in the frequency domain (0 ≤ f_id < 8), and ul_carrier_id is the carrier used for Msg1 transmission (0 for normal UL (NUL) carrier and 1 for supplementary UL (SUL) carrier). The gNB can multiplex several RARs for each random access preamble detected by the gNB into the same RAR MAC protocol data unit (PDU). If the RAR includes the RA preamble identifier (RAPID) of the RA preamble sent by the UE, then the RAR in the MAC PDU corresponds to the RA preamble transmission of the UE. If no RAR corresponding to its RA preamble transmission is received during the RAR window, and the UE has not sent a RA preamble for a configurable (configured by the gNB in ​​the RACH configuration) number of times, then the UE returns to the first step, i.e. selecting a random access resource (preamble / RACH opportunity) and sending a RA preamble. A backoff period may be applied before returning to the first step.

[0050] If a RAR corresponding to its RA preamble transmission is received, the UE sends a message 3 (Msg3) in the UL grant received in the RAR. Msg3 includes messages such as RRC connection request, RRC connection reestablishment request, RRC handover confirmation, scheduling request, SI request, etc. It may include a UE identity (i.e., a cell radio network temporary identifier (C-RNTI) or a system architecture evolution (SAE)-temporary mobile subscriber identity (S-TMSI) or a random number). After sending Msg3, the UE starts a contention resolution timer. While the contention resolution timer is running, if the UE receives a PDCCH addressed to the C-RNTI included in Msg3, the contention resolution is considered successful, the contention resolution timer stops and the RA procedure is completed. While the contention resolution timer is running, if the UE receives a contention resolution MAC control element (CE) including the UE's contention resolution identity (the first X bits of the common control channel (CCCH) service data unit (SDU) sent in Msg3), the contention resolution is considered successful, the contention resolution timer stops and the RA procedure is completed. If the contention resolution timer expires and the UE has not sent a RA preamble for a configurable number of times, the UE returns to the first step, i.e., selecting random access resources (preamble / RACH opportunity) and sending a RA preamble. Before returning to the first step, a backoff period may be applied.

[0051] Contention Free Random Access (CFRA): This is also known as legacy CFRA or 4-step CFRA. The CFRA procedure is used for scenarios such as handovers where low latency is required, timing advance establishment of Scells, etc. The evolved Node B (or gNB) allocates a dedicated random access preamble to the UE. The UE sends a dedicated RA preamble. The ENB (or gNB) sends a RAR on the PDSCH addressed to the RA-RNTI. The RAR conveys the RA preamble identifier and timing alignment information. The RAR may also include an UL grant. Similar to the CBRA procedure, the RAR is sent in the RAR window. The CFRA is considered to be successfully completed after receiving the RAR including the RAPID of the RA preamble sent by the UE. In case RA is initiated for beam failure recovery, the CFRA is considered to be successfully completed if a PDCCH addressed to the C-RNTI is received in the search space for beam failure recovery. If the RAR window expires and the RA is not successfully completed, and the UE has not sent the RA preamble for a configurable number of times (configured by the gNB in ​​the RACH configuration), the UE retransmits the RA preamble.

[0052] For specific events, such as handover and beam failure recovery, if (multiple) dedicated preambles are allocated to the UE, then during the first step of random access, i.e., during random access resource selection for Msg1 transmission, the UE determines whether to send a dedicated preamble or a non-dedicated preamble. Dedicated preambles are usually provided for a subset of SSB / CSI-RS. If there is no SSB / CSI RS with DL reference signal received power (RSRP) above the threshold among the SSB / CSI-RS for which the gNB provides contention-free random access resources (i.e., dedicated preambles / RO), the UE selects a non-dedicated preamble. Otherwise, the UE selects a dedicated preamble. Therefore, during the RA procedure, one random access attempt can be CFRA and the other random access attempt can be CBRA.

[0053] 2-step Contention Based Random Access (2-step CBRA): In the first step, the UE transmits a random access preamble on PRACH and a payload (i.e., MAC PDU) on PUSCH. The random access preamble and payload transmission is also referred to as MsgA. In the second step, after the MsgA transmission, the UE monitors the response from the network (i.e., gNB) within the configured window. The response is also referred to as MsgB. If a CCCH SDU is transmitted in the MsgA payload, the UE performs contention resolution using the contention resolution information in the MsgB. Contention resolution is successful if the contention resolution identifier received in the MsgB matches the first 48 bits of the CCCH SDU transmitted in the MsgA. If the C-RNTI is transmitted in the MsgA payload, contention resolution is successful if the UE receives a PDCCH addressed to the C-RNTI. If contention resolution is successful, the random access procedure is considered to be successfully completed. Instead of the contention resolution information corresponding to the transmitted MsgA, MsgB may include backoff information corresponding to the random access preamble transmitted in MsgA. If the backoff information is received, the UE transmits Msg3 and performs contention resolution using Msg4 as in the CBRA process. If the contention resolution is successful, the random access process is deemed to have been successfully completed. If contention resolution fails at the time of backoff (i.e., when Msg3 is transmitted), the UE retransmits MsgA. If the configured window in which the UE monitors the network response after transmitting MsgA expires, and the UE does not receive MsgB including the contention resolution information or backoff information as above, the UE retransmits MsgA. If the random access process is not successfully completed even after transmitting MsgA a configurable number of times, the UE falls back to the 4-step RACH process, i.e., the UE transmits only the PRACH preamble.

[0054] The MsgA payload may include one or more of a CCCH SDU, a dedicated control channel (DCCH) SDU, a dedicated traffic channel (DTCH) SDU, a buffer status report (BSR) MAC CE, a power headroom report (PHR) MAC CE, SSB information, a C-RNTI MAC CE, or padding. MsgA may include a UE ID (e.g., a random ID, S-TMSI, C-RNTI, recovery ID, etc.) and the preamble in the first step. The UE ID may be included in the MAC PDU of MsgA. A UE ID such as a C-RNTI may be carried in a MAC CE, where the MAC CE is included in the MAC PDU. Other UE IDs (such as a random ID, S-TMSI, C-RNTI, recovery ID, etc.) may be carried in a CCCH SDU. The UE ID may be one of a random ID, S-TMSI, C-RNTI, recovery ID, IMSI, idle mode ID, inactive mode ID, etc. The UE ID may be different in different scenarios where the UE performs a RA procedure. When the UE performs RA after power-on (before it attaches to the network), the UE ID is a random ID. When the UE performs RA in the IDLE state after it attaches to the network, the UE ID is the S-TMSI. If the UE has an assigned C-RNTI (for example, in a connected state), the UE ID is the C-RNTI. In the case where the UE is in the INACTIVE state, the UE ID is a recovery ID. In addition to the UE ID, some additional control information may be sent in the MsgA. The control information may be included in the MAC PDU of the MsgA. The control information may include a connection request indication, a connection recovery request indication, an SI request indication, a buffer status indication, beam information (for example, one or more DL TX beam IDs or SSB IDs), a beam failure recovery indication / information, a data indicator, a cell / BS / transmitting receiving point (TRP) switching indication, a connection reestablishment indication, a reconfiguration completion or switching completion message, and the like. One or more.

[0055] 2-step Contention-Free Random Access (2-step CFRA): In this case, the gNB allocates to the UE (multiple) dedicated random access preambles and (multiple) PUSCH resources for MsgA transmission. The (multiple) ROs to be used for preamble transmission may also be indicated. In the first step, the UE sends a random access preamble on PRACH and payload on PUSCH using contention-free random access resources (i.e., dedicated preamble / PUSCH resources / RO). In the second step, after MsgA transmission, the UE monitors for a response from the network (i.e., gNB) within a configured window. If the UE receives a PDCCH addressed to the C-RNTI, the random access procedure is considered to be successfully completed. If the UE receives backoff information corresponding to the preamble it sent, the random access procedure is considered to be successfully completed.

[0056] For specific events, such as handover and beam failure recovery, if dedicated preamble(s) and PUSCH resources(s) are allocated to the UE, then during the first step of random access, i.e., during random access resource selection for MsgA transmission, the UE determines whether to send a dedicated preamble or a non-dedicated preamble. Dedicated preambles are typically provided for a subset of SSB / CSI-RS. If there is no SSB / CSI-RS with DL RSRP above a threshold among the SSB / CSI RS for which contention-free random access resources (i.e., dedicated preamble / RO / PUSCH resources) are provided by the gNB, the UE selects a non-dedicated preamble. Otherwise, the UE selects a dedicated preamble. Therefore, during the RA procedure, one random access attempt can be a 2-step CFRA, while the other random access attempt can be a 2-step CBRA.

[0057] When initiating a random access procedure, the UE first selects a carrier (SUL or NUL). If the carrier for the random access procedure is explicitly signaled by the gNB, the UE selects the signaled carrier to perform the random access procedure. If the gNB does not explicitly signal the carrier for the random access procedure; and if the serving cell for the random access procedure is configured with a supplementary uplink, and if the RSRP referenced by the downlink path loss is less than rsrp-ThresholdSSB-SUL: the UE selects the SUL carrier for performing the random access procedure. Otherwise, the UE selects the NUL carrier to perform the random access procedure. Once the UL carrier is selected, the UE determines the UL and DL BWP for the random access procedure, as specified in Section 5.15 of TS38.321. The UE then determines whether to perform a 2-step or 4-step RACH for the random access procedure.

[0058] - If the random access procedure is initiated by a PDCCH order and if the ra-PreambleIndex explicitly provided by the PDCCH is not 0b000000, the UE selects 4-step RACH.

[0059] - Otherwise, if the gNB signals 2-step contention-free random access resources for this random access procedure, the UE selects 2-step RACH.

[0060] - Otherwise, if the gNB signals 4-step contention-free random access resources for this random access procedure, the UE selects 4-step RACH.

[0061] - Otherwise, if the UL BWP selected for this random access procedure is only configured with 2-step RACH resources, the UE selects 2-step RACH.

[0062] - Otherwise, if the UL BWP selected for this random access procedure is only configured with 4-step RACH resources, the UE selects 4-step RACH.

[0063] - Otherwise, if the UL BWP selected for this random access procedure is configured with both 2-step and 4-step RACH resources,

[0064] -*If the downlink path loss referenced RSRP is below the configured threshold, the UE selects 4-step RACH. Otherwise, the UE selects 2-step RACH.

[0065] In the fifth generation wireless communication system, the Node B (or gNB) or base station in the cell broadcasts a synchronization signal and a physical broadcast channel (PBCH) block (ie, SSB), where the SSB consists of a primary synchronization signal and a 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 known as the next generation radio or NR), the system information (SI) is divided into a master information block (MIB) and multiple system information blocks (SIBs), where:

[0066] -MIB is always transmitted on BCH with a period of 80 milliseconds (ms) and repeated within 80 ms, and it includes the parameters required to obtain SIB1 from the cell.

[0067] -SIB1 is transmitted on the downlink shared channel (DL-SCH) with a periodicity of 160ms and a variable transmission repetition. The default transmission repetition period of SIB1 is 20ms, but the actual transmission repetition period depends on the network implementation. The scheduling information in SIB 1 includes the mapping between SIBs and SI messages, the periodicity of each SI message, and the SI window length. The scheduling information in SIB 1 includes an indicator for each SI message that indicates whether the associated SI message is being broadcast. If at least one SI message is not being broadcast, SIB1 may include random access resources ((multiple) PRACH preambles and (multiple) PRACH resources) for requesting the gNB to broadcast one or more SI messages.

[0068] -SIBs other than SIB1 are carried in a system information (SI) message, which is transmitted on the DL-SCH. Only SIBs with the same period can be mapped to the same SI message. Each SI message is transmitted within a time domain window that occurs periodically (called an SI window with the same length for all SI messages). Each SI message is associated with an SI window, and the SI windows of different SI messages do not overlap. That is, within an SI window, only the corresponding SI message is transmitted. Using the indication in SIB1, any SIB except SIB1 can be configured as cell-specific or area-specific. A cell-specific SIB is applicable only within the cell that provides the SIB, while an area-specific SIB is applicable within an area called an SI area, where the SI area consists of one or several cells and is identified by systemInformationAreaID.

[0069] The UE obtains SIB 1 from the resident or serving cell. The UE checks the BroadcastStatus bit in SIB 1 for the SI message that the UE needs to obtain. The gNB uses IE si-RequestConfigSUL in SIB1 to signal the SI request configuration for SUL. If IE si-RequestConfigSUL does not exist in SIB1, the UE considers that the gNB has not signaled the SI request configuration for SUL. The gNB uses IE si-RequestConfig in SIB1 to signal the SI request configuration for NUL. If IE si-RequestConfig does not exist in SIB1, the UE considers that the gNB has not signaled the SI request configuration for NUL. If the SI message that the UE needs to obtain is not broadcast (i.e., the BroadcastStatus bit is set to zero), the UE initiates the transmission of the SI request. The process of SI request transmission is as follows:

[0070] If the gNB has signaled an SI request configuration for SUL signaling and the criteria for selecting SUL are met (i.e., RSRP derived from the SSB measurement of the resident or serving cell < rsrp-ThresholdSSB-SUL, where rsrp-ThresholdSSB-SUL is signaled by the gNB (e.g., in broadcast signaling such as SIB1)): The UE initiates the transmission of an SI request based on a Msg1-based SI request on SUL. In other words, the UE uses the (multiple) PRACH preambles and (multiple) PRACH resources in the SI request configuration of SUL to initiate a random access procedure. The UE sends Msg1 (i.e., the random access preamble) and waits for an acknowledgement of the SI request. The random access resources (the (multiple) PRACH preambles and (multiple) PRACH occasions) indicated in the SI request configuration of SUL are used for Msg1. Msg1 is transmitted on SUL. If an acknowledgement of the SI request is received, the UE monitors the SI window of the requested SI message during one or more SI periods of that SI message.

[0071] Otherwise, if the gNB has signaled an SI request configuration for NUL signaling and the criteria for selecting NUL are met (i.e., NUL is selected if SUL is supported in the resident or serving cell and RSRP derived from the SSB measurement of the resident or serving cell >= rsrp-ThresholdSSB-SUL; or NUL is selected if SUL is not supported in the serving cell): The UE initiates the transmission of an SI request based on a Msg1-based SI request on NUL. In other words, the UE uses the (multiple) PRACH preambles and (multiple) PRACH resources in the SI request configuration of NUL to initiate a random access procedure. The UE sends Msg1 (i.e., the random access preamble) and waits for an acknowledgement of the SI request. The random access resources (the (multiple) PRACH preambles and (multiple) PRACH occasions) indicated in the SI request configuration of NUL are used for Msg1. Msg1 is transmitted on NUL. If an acknowledgement of the SI request is received, the UE monitors the SI window of the requested SI message during one or more SI periods of that SI message.

[0072] Otherwise, the UE initiates the transmission of the SI request based on the SI request based on Msg3. In other words, the UE initiates the transmission of the RRCSystemInfoRequest message. The UE sends Msg1 (i.e., the random access preamble) and waits for the random access response. The common random access resources ((multiple) PRACH preambles and (multiple) PRACH occasions) are used for Msg1. In the UL grant received in the random access response, the UE sends the RRCSystemInfoRequest message and waits for the confirmation of the SI request (i.e., the RRCSystemInfoRequest message). If the confirmation of the SI request (i.e., the RRCSystemInfoRequest message) is received, the UE monitors the SI window of the requested SI message in one or more SI periods of this SI message. Note that if SUL is configured, the UL carrier used for Msg1 transmission will be selected by the UE in a manner similar to that selected by the UE for the SI request based on Msg1. If the RSRP derived from the SSB measurement of the resident or serving cell < rsrp-ThresholdSSB-SUL, then the SUL is the selected UL carrier, where rsrp-ThresholdSSB-SUL is signaled by the gNB (e.g., in broadcast signaling such as SIB1). If the RSRP derived from the SSB measurement of the resident or serving cell >= rsrp-ThresholdSSB-SUL, then the NUL is the selected UL carrier, where rsrp-ThresholdSSB-SUL is signaled by the gNB (e.g., in broadcast signaling such as SIB1).

[0073] However, there are some problems in the current SI request process.

[0074] - Problem 1: Delay in the completion of handover when dedicated SIB1 is configured

[0075] The SI request mechanism is being enhanced to enable the UE to request SI in the RRC connected state. According to the existing procedures, the UE can receive a handover command (i.e., an RRC reconfiguration message including synchronization reconfiguration) from the source SpCell. If the handover command includes a dedicatedSIB1-Delivery IE, the RRC in the UE performs actions upon receipt of SIB1 as specified in TS 38.331 before triggering the RRCReconfigurationComplete message. The dedicatedSIB1-Delivery IE provides the SIB1 of the target cell. As part of the SIB 1 processing triggered by the reception of the dedicatedSIB1-Delivery IE, if the UE requires (multiple) SIBs other than SIB1 in the RRC connected state and these SIBs are not broadcast in the target cell as per the received SIB1, the DedicatedSIBRequest is triggered. As a result, the DedicatedSIBRequest will be queued before the RRCReconfigurationComplete, which will delay the transmission of the RRCReconfigurationComplete and thus delay the handover completion.

[0076] -Problem 2: Unable to obtain SIB in RRC state

[0077] The UE is in RRC connected state. The UE wants to receive SIB (e.g., V2X is activated and the UE needs V2X SIB). The UE first needs to obtain SIB 1.

[0078] If the si-BroadcastStatus of the required SIB in SIB1 is set to notBroadcasting, the UE triggers DedicatedSIBRequest. Otherwise, the UE obtains the SI message of the required SIB from the broadcast. In the RRC connected state, if no common search space is configured in the active DL BWP, the UE cannot obtain SIB1. As a result, the UE cannot obtain the required SIB.

[0079] The present disclosure provides methods and devices for dealing with the above problems. Hereinafter, those skilled in the art may freely combine or reconfigure the embodiments disclosed in the present disclosure, for example, each part of the embodiments may be combined with each other to form an embodiment.

[0080] Embodiment 1 - SI request when receiving SIB1 during handover

[0081] [Example 1-1]

[0082] In one method of the present disclosure, the processing of SIB1 is divided into two parts:

[0083] -The first part includes the processing of si-SchedulingInfo;

[0084] - The second part includes the processing of contents (parameters / IEs) other than si-SchedulingInfo.

[0085] Figure 1 A flowchart of processing SIB1 during a handover process according to an embodiment of the present disclosure is shown.

[0086] In step 101, the UE receives an RRC reconfiguration message from the network (ie, base station), the message including the reconfigurationWithSync IE (in the SpCellConfig of the MCG) and the dedicatedSIB1-Delivery IE.

[0087] In step 102, the RRC layer in the UE processes the synchronous reconfiguration:

[0088] *1>Start the timer T304 corresponding to SpCell, and set the timer value to t304, including in reconfigurationWithSync

[0089] *1>If frequencyInfoDL is included:

[0090] **2> Treat the target SpCell as the one on the SSB frequency indicated by frequencyInfoDL, which has a physical cell identity indicated by physCellId;

[0091] *1>Otherwise:

[0092] **2> The target SpCell is considered to be the one on the SSB frequency of the source SpCell, which has a physical cell identity indicated by physCellId;

[0093] *1>Start synchronization to the DL of the target SpCell;

[0094] *1>Apply predefined BCCH configuration;

[0095] *1>Get MIB if necessary

[0096] *1> Reset the MAC entity of the cell group;

[0097] *1>The (multiple) SCells of the cell group (if configured) are considered to be in a deactivated state.

[0098] *1> Apply the value of newUE-Identity as the C-RNTI of the cell group;

[0099] In step 103, the RRC layer in the UE processes the dedicatedSIB1-Delivery IE and applies the content in the second part of SIB1:

[0100] *1> If cellAccessRelatedInfo contains an entry with the PLMN identity of the selected PLMN:

[0101] **2> In the remaining process, the plmn-IdentityList, trackingAreaCode and cellIdentity of the cell received in the corresponding PLMN-IdentityInfo containing the selected PLMN are used;

[0102] *1>When in RRC_CONNECTED, ignore frequencyBandList (if received);

[0103] *1>Forward cellIdentity to the upper layer;

[0104] *1>Forward trackingAreaCode to the upper layer;

[0105] *1>Apply the configuration included in servingCellConfigCommon;

[0106] In step 104, the RRC layer initiates transmission of an RRC reconfiguration complete message, and this triggers initiation of a random access procedure to the target SpCell.

[0107] In step 105, upon completion of the random access procedure, the RRC layer in the UE processes the dedicatedSIB1-Delivery IE and applies the content in the first part of SIB1 as follows:

[0108] *- If the UE has a stored valid version of the SIBs required for the UE to operate in the cell:

[0109] **- Use the stored version of the desired SIB;

[0110] *- If the UE does not store a valid version of one or several of the required SIBs:

[0111] **-For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0112] **- For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting: trigger DedicatedSIBRequest to obtain the required SIB(s).

[0113] Alternatively, in step 105, upon completion of the random access procedure, the RRC layer in the UE processes the dedicatedSIB1-Delivery IE and applies the content in the first part of SIB1 as follows:

[0114] *- If the UE has a stored valid version of the SIBs required for the UE to operate in the cell:

[0115] **- Use the stored version of the desired SIB;

[0116] *- If the UE does not store a valid version of one or several of the required SIBs:

[0117] **- If common search space is configured in active DL BWP:

[0118] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0119] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting: trigger DedicatedSIBRequest to obtain the required SIB(s).

[0120] **-otherwise

[0121] ***Trigger DedicatedSIBRequest to get the required SIB(s).

[0122] According to another embodiment of the present disclosure, in step 105, upon completion of the random access procedure, the RRC layer in the UE processes the dedicatedSIB1-Delivery IE and applies the content in the first part of SIB1 as follows:

[0123] *- If the UE has a stored valid version of the SIBs required for the UE to operate in the cell:

[0124] **- Use the stored version of the desired SIB;

[0125] *- If the UE does not store a valid version of one or several of the required SIBs:

[0126] **- Trigger DedicatedSIBRequest to get the required SIB(s).

[0127] [Example 1-2]

[0128] Figure 2 A flowchart of processing SIB1 received in the RRC connected state according to an embodiment of the present disclosure is shown.

[0129] In step 201, the UE receives SIB 1 in the RRC connected state. SIB 1 may be received in an RRC reconfiguration message or acquired by the UE from a broadcast.

[0130] The UE processes SIB 1 as follows:

[0131] *- If cellAccessRelatedInfo contains an entry with the PLMN identity of the selected PLMN:

[0132] **- In the remaining process, the plmn-IdentityList, trackingAreaCode and cellIdentity of the cell received in the corresponding PLMN-IdentityInfo containing the selected PLMN are used;

[0133] *-When in RRC_CONNECTED, ignore frequencyBandList (if received);

[0134] *-Forward cellIdentity to the upper layer;

[0135] *-Forward trackingAreaCode to the upper layer;

[0136] *-Apply the configuration included in servingCellConfigCommon (202);

[0137] *- If the UE has a stored valid version of the SIBs required for the UE to operate in the cell:

[0138] **- Use the stored version of the desired SIB;

[0139] *- If the UE does not store a valid version of a SIB among one or several required SIBs (203):

[0140] **-For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0141] **- For SI message(s) (204) containing at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting:

[0142] *** If this SIB1 is received in RRCReconfiguration including reconfigurationWithSync in spCellConfig of MCG (205):

[0143] ****When the MCG's MAC completes the random access process to the target SpCell, the UE triggers DedicatedSIBRequest (206)

[0144] ***otherwise:

[0145] ****Trigger DedicatedSIBRequest to obtain the required SIB(s) (207).

[0146] Alternatively, in step 203, if the UE does not store a valid version of a SIB in one or more required SIBs:

[0147] **- For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting and common search space is configured in the active DL BWP: get SI message(s) from broadcast;

[0148] **- For SI message(s) containing at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting or no common search space is configured in the active DL BWP:

[0149] *** If this SIB1 is received in RRCReconfiguration including reconfigurationWithSync in spCellConfig of MCG:

[0150] ****When the MCG's MAC completes the random access process to the target SpCell, the UE triggers DedicatedSIBRequest

[0151] ***otherwise:

[0152] ****Trigger DedicatedSIBRequest to obtain the required SIB(s) (207).

[0153] According to another embodiment of the present disclosure, in step 203, if the UE does not store a valid version of a SIB in one or more required SIBs:

[0154] **- If this SIB1 is received in RRCReconfiguration including reconfigurationWithSync in spCellConfig of MCG:

[0155] ***When the MCG's MAC completes the random access process to the target SpCell, the UE triggers DedicatedSIBRequest

[0156] **- Otherwise, if this SIB1 is received in RRCReconfiguration

[0157] ***Trigger DedicatedSIBRequest to get the required SIB(s).

[0158] **-otherwise

[0159] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0160] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting:

[0161] ****Trigger DedicatedSIBRequest to obtain the required SIB(s).

[0162] [Examples 1-3]

[0163] Figure 3 A flowchart of processing SIB1 received in the RRC connected state according to another embodiment of the present disclosure is shown.

[0164] In step 301, the UE receives SIB 1 in the RRC connected state. SIB 1 may be received in an RRC reconfiguration message, or acquired by the UE from a broadcast.

[0165] The UE processes SIB 1 as follows:

[0166] *- If cellAccessRelatedInfo contains an entry with the PLMN identity of the selected PLMN:

[0167] **- In the remaining process, the plmn-IdentityList, trackingAreaCode and cellIdentity of the cell received in the corresponding PLMN-IdentityInfo containing the selected PLMN are used;

[0168] *-When in RRC_CONNECTED, ignore frequencyBandList (if received);

[0169] *-Forward cellIdentity to the upper layer;

[0170] *-Forward trackingAreaCode to the upper layer;

[0171] *-Apply the configuration included in servingCellConfigCommon (302);

[0172] *- If the UE has a stored valid version of the SIBs required for the UE to operate in the cell:

[0173] **- Use the stored version of the desired SIB;

[0174] *- If the UE does not store a valid version of a SIB among one or several required SIBs (303):

[0175] **-For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0176] **- For SI message(s) (304) containing at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting:

[0177] *** If the SIB1 is received in the RRCReconfiguration message (i.e., in the dedicatedSIB1-Delivery IE) (305):

[0178] ****UE triggers DedicatedSIBRequest (306) after submitting RRCReconfigurationComplete message to lower layer for transmission via SRB1

[0179] ***otherwise:

[0180] **** Trigger DedicatedSIBRequest to obtain the required SIB(s). (307)

[0181] Alternatively, in step 303, if the UE does not store a valid version of a SIB in one or more required SIBs:

[0182] **- For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting and common search space is configured in the active DL BWP: get SI message(s) from broadcast;

[0183] **- For SI message(s) containing at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting or no common search space is configured in the active DL BWP:

[0184] *** If the SIB1 is received in the RRCReconfiguration message (i.e., in the dedicatedSIB1-Delivery IE):

[0185] ****UE triggers DedicatedSIBRequest after submitting RRCReconfigurationComplete message to lower layer for transmission via SRB1

[0186] ***otherwise:

[0187] ****Trigger DedicatedSIBRequest to obtain the required SIB(s).

[0188] According to another embodiment of the present disclosure, in step 303, if the UE does not store a valid version of a SIB in one or more required SIBs:

[0189] **- If this SIB1 is received in the RRCReconfiguration message:

[0190] ****UE triggers DedicatedSIBRequest after submitting RRCReconfigurationComplete message to lower layer for transmission via SRB1

[0191] **-otherwise

[0192] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to broadcasting: get SI message(s) from broadcast;

[0193] ***For SI message(s) that contain at least one required SIB according to si-SchedulingInfo and whose si-BroadcastStatus is set to notBroadcasting:

[0194] ****Trigger DedicatedSIBRequest to obtain the required SIB(s).

[0195] Example 2-Triggering the sending of DedicatedSIBRequest

[0196] When the UE is in the RRC connected state and the UE wants to receive SIBs (e.g., V2X is activated and the UE requires V2X SIBs), and if the UE does not have a stored valid version of the SIBs required for the UE to operate within the cell, the UE obtains the required SIBs as follows:

[0197] *- If the UE is in RRC IDLE / INACTIVE state:

[0198] **-UE first acquires SIB1. In an embodiment, if the UE already has acquired SIB1 in the current modification period and si-BroadcastStatus for the required SIB in SIB1 is set to Broadcasting, the UE does not need to acquire SIB1 (ie, the UE does not acquire SIB1 in this step).

[0199] **-If si-BroadcastStatus for the required SIB in the acquired SIB1 is set to notBroadcasting, the UE triggers an SI request based on Msg1 or Msg3. It is explained earlier in this disclosure whether to trigger an SI request based on Msg1 or Msg3.

[0200] **- Otherwise UE obtains the SI message of the required SIB from the broadcast

[0201] *- Otherwise (i.e., UE is in RRC connected state):

[0202] **- If there is a public search space in the active DL BWP:

[0203] ***-UE first acquires SIB1. In an embodiment, if the UE already has acquired SIB1 in the current modification period, and si-BroadcastStatus for the required SIB in SIB1 is set to Broadcasting, the UE does not need to acquire SIB1 (ie, the UE does not acquire SIB1 in this step).

[0204] ***-If si-BroadcastStatus is set to notBroadcasting in the acquired SIB1:

[0205] ****UE triggers DedicatedSIBRequest

[0206] ***Otherwise UE obtains the SI message of the required SIB from the broadcast

[0207] **-otherwise:

[0208] ***UE triggers DedicatedSIBRequest

[0209] The DedicatedSIBRequest message includes requestedSIB-List-r16. requestedSIB-List-r16 includes a list of required SIBs. In an embodiment, requestedSIB-List-r16 is a bitmap, where each bit corresponds to a different SIB. SIB 1 to SIB 9 are defined in Release 15 (R15) of the 3GPP standard. New SIBs will be further added in Release 16 (R16). The question is which SIBs can be requested via requestedSIB-List-r16 and how the bits in requestedSIB-List-r16 are mapped to SIBs.

[0210] [Example 2-1]

[0211] Only R16 SIB can be requested via DedicatedSIBRequest.

[0212] The first bit in requestedSIB-List-r16 corresponds to SIB 10, the second bit corresponds to SIB 11, and so on.

[0213] Alternatively, the first bit in requestedSIB-List-r16 corresponds to SIB 2, the second bit corresponds to SIB3, etc. The bits corresponding to SIB2 to SIB 9 are always set to zero.

[0214] [Example 2-2]

[0215] R16 SIB and R15 SIB can be requested through DedicatedSIBRequest.

[0216] The first bit in requestedSIB-List-r16 corresponds to SIB 2, the second bit corresponds to SIB 3, and so on.

[0217] [Example 2-3]

[0218] Only SIBs required under RRC connection can be requested through DedicatedSIBRequest.

[0219] The SIBs required for the RRC connection are pre-specified.

[0220] The bits in requestedSIB-List-r16 are mapped to the SIBs required for the connection in ascending order of SIB# starting from the first bit.

[0221] -Example

[0222] SIB 12, SIB 14 and SIB 16 are required for RRC connection

[0223] The first bit in requestedSIB-List-r16 corresponds to SIB12, the second bit corresponds to SIB14, and the third bit corresponds to SIB16.

[0224] [Examples 2-4]

[0225] R16 SIB and SIBs 6, 7, and 8 can be requested via DedicatedSIBRequest.

[0226] The first bit in requestedSIB-List-r16 corresponds to SIB 6, the second bit corresponds to SIB 7, and so on.

[0227] Example 3 - si-BroadcastStatus bit setting in SIB1

[0228] All contents in SIB1 are cell-specific. Therefore, the contents of SIB1 transmitted on one or more DL BWPs of the serving cell are the same. However, it is inefficient to set the value of the parameter si-BroadcastStatus corresponding to the SI message to the same in all DL BWPs. SIB1 can be delivered to the UE on the DL BWP using dedicated signaling, and (multiple) SI messages may not be broadcast on this DL BWP because no common search space is configured on this DL BWP. However, in other DL BWPs, a common search may be configured and (multiple) SI messages may be broadcast.

[0229] In one embodiment, if SIB1 is delivered or sent by the gNB on a DL BWP (such as BWP ID X), if the SI message is not broadcast in DL BWP X, the si-BroadcastStatus corresponding to the SI message in SIB1 is set to not broadcast. If SIB1 is delivered or sent by the gNB on a DL BWP (such as BWP ID X), if the SI message is broadcast in DL BWP X, the si-BroadcastStatus corresponding to the SI message in SIB1 is set to broadcast.

[0230] In another embodiment, if SIB1 is delivered by the gNB using dedicatedSIB1-Delivery IE, the si-BroadcastStatus corresponding to the SI message in SIB1 is set to not broadcast. If SIB1 is not delivered by the gNB using dedicatedSIB1-Delivery IE (i.e., SIB1 is broadcast by the GNB), if the SI message is not broadcast in the DL BWP in which SIB1 is transmitted, the si-BroadcastStatus corresponding to the SI message in SIB1 is set to not broadcast. If SIB1 is not delivered by the gNB using dedicatedSIB1-Delivery IE (i.e., SIB1 is broadcast by the GNB), if the SI message is broadcast in the DL BWP in which SIB1 is transmitted, the si-BroadcastStatus corresponding to the SI message in SIB1 is set to broadcast.

[0231] Figure 4 is a block diagram of a terminal according to an embodiment of the present disclosure.

[0232] refer to Figure 4 The terminal includes a transceiver 410, a controller 420, and a memory 430. The controller 420 may refer to a circuit system, an application specific integrated circuit (ASIC), or at least one processor. The transceiver 410, the controller 420, and the memory 430 are configured to execute the drawings (for example, Figures 1 to 3 ) or the operations of the UE described above. Although the transceiver 410, the controller 420, and the memory 430 are shown as separate entities, they may be implemented as a single entity, such as a single chip. Alternatively, the transceiver 410, the controller 420, and the memory 430 may be electrically connected or coupled to each other.

[0233] The transceiver 410 may transmit and receive signals to and from other network entities (eg, a base station).

[0234] The controller 420 may control the terminal to perform the functions according to one of the above embodiments. For example, the controller 420 controls the transceiver 410 and / or the memory 430 to perform operations related to the random access procedure according to various embodiments of the present disclosure.

[0235] In an embodiment, the operation of the terminal can be implemented using a memory 430 storing a corresponding program code. Specifically, the terminal can be equipped with a memory 430 to store the program code for implementing the desired operation. In order to perform the desired operation, the controller 420 can read and execute the program code stored in the memory 430 by using at least one processor or a central processing unit (CPU).

[0236] Figure 5 is a block diagram of a base station according to an embodiment of the present disclosure.

[0237] refer to Figure 5 , the base station includes a transceiver 510, a controller 520, and a memory 530. The controller 520 may refer to a circuit system, an application specific integrated circuit (ASIC), or at least one processor. The transceiver 510, the controller 520, and the memory 530 are configured to execute the drawings (for example, Figures 1 to 3 ) or the operations of the UE described above. Although the transceiver 510, the controller 520, and the memory 530 are shown as separate entities, they may be implemented as a single entity, such as a single chip. Alternatively, the transceiver 510, the controller 520, and the memory 530 may be electrically connected or coupled to each other.

[0238] The transceiver 510 may transmit and receive signals to and from other network entities (eg, terminals).

[0239] The controller 520 may control the UE to perform the functions according to one of the above embodiments. For example, the controller 520 controls the transceiver 510 and / or the memory 530 to perform operations related to the random access procedure according to various embodiments of the present disclosure.

[0240] In an embodiment, the operation of the base station can be implemented using a memory 530 storing a corresponding program code. Specifically, the base station can be equipped with a memory 530 to store a program code for implementing the desired operation. In order to perform the desired operation, the controller 520 can read and execute the program code stored in the memory 530 by using at least one processor or a central processing unit (CPU).

[0241] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

[0242] As described above, the embodiments disclosed in the specification and the drawings are only used to present specific examples to easily explain the content of the present disclosure and help understanding, and are not intended to limit the scope of the present disclosure. Therefore, in addition to the embodiments disclosed herein, the scope of the present disclosure should be analyzed to include all changes or modifications derived from the technical concept of the present disclosure.

[0243] Although the present disclosure has been described with various embodiments, various changes and modifications may occur to those 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 performed by a terminal in a wireless communication system, the method comprising: In a radio resource control RRC connected state, receiving an RRC message including a system information block 1 (SIB1) and information associated with synchronization reconfiguration of a target special cell SpCell, wherein for dual connectivity, the SpCell refers to a primary cell PCell of a primary cell group MCG or a primary SCG cell PSCell of a secondary cell group SCG; identifying that the terminal does not store a valid version of the SIB; and In case the RRC message is associated with the MCG and includes SIB1 and information associated with synchronization reconfiguration of the target SpCell, a dedicated SIB request message for the SIB is sent to the target SpCell after a random access procedure to the target SpCell is completed.

2. The method according to claim 1, wherein: In the case where the media access control MAC of the MCG completes the random access procedure, the random access procedure is completed, and The information associated with synchronous reconfiguration includes information about a timer used for the corresponding SpCell.

3. The method according to claim 1, further comprising: Identify whether a common search space is configured for the active bandwidth part BWP, Wherein, the dedicated SIB request message is sent when a common search space is not configured for an active BWP and the terminal does not store a valid version of the SIB.

4. The method according to claim 3, further comprising: Based on the scheduling information included in the SIB1, identifying whether the system information broadcast state is set to non-broadcast, and Wherein, the dedicated SIB request message is sent when a common search space is configured for the active BWP and the system information broadcast state is set to non-broadcast.

5. A method performed by a target special cell SpCell in a wireless communication system, the method comprising: Performing a random access procedure with a terminal, the terminal being in a radio resource control RRC connected state with a source SpCell; as well as In the case where the RRC message sent from the source SpCell to the terminal is associated with a master cell group MCG and includes SIB1 and information associated with synchronization reconfiguration of the target SpCell, after the random access procedure is completed, receiving a dedicated SIB request message for a system information block SIB from the terminal, Among them, for dual connectivity, SpCell refers to the primary cell PCell of the MCG or the primary SCG cell PSCell of the secondary cell group SCG.

6. The method according to claim 5, wherein: In the case where the medium access control MAC of the MCG completes the random access procedure, the random access procedure is completed, and The information associated with synchronous reconfiguration includes information about a timer used for the corresponding SpCell.

7. The method according to claim 5, in, The dedicated SIB request message is received in a case where a common search space is not configured for an active bandwidth part BWP, or in a case where a common search space is configured for an active BWP and a system information broadcast status included in the SIB1 is set to not broadcast.

8. A terminal in a wireless communication system, the terminal comprising: a transceiver (410) configured to transmit and receive signals; and A controller (420) is coupled to the transceiver and is configured to: In a radio resource control RRC connected state, an RRC message including a system information block 1 (SIB1) and information associated with synchronization reconfiguration of a target special cell SpCell is received, wherein for dual connectivity, the SpCell refers to a primary cell PCell of a primary cell group MCG or a primary SCG cell PSCell of a secondary cell group SCG, Identify that the terminal does not store a valid version of the SIB, In case the RRC message is associated with the MCG and includes SIB1 and information associated with synchronization reconfiguration of the target SpCell, a dedicated SIB request message for the SIB is sent to the target SpCell after a random access procedure to the target SpCell is completed.

9. The terminal according to claim 8, wherein: In the case where the medium access control MAC of the MCG completes the random access procedure, the random access procedure is completed, and The information associated with synchronous reconfiguration includes information about a timer used for the corresponding SpCell.

10. The terminal according to claim 8, wherein: The controller is further configured to identify whether a common search space is configured for the active bandwidth part BWP, and Wherein, the dedicated SIB request message is sent when a common search space is not configured for an active BWP and the terminal does not store a valid version of the SIB. The terminal according to claim 10 , wherein: The controller is further configured to: identify whether the system information broadcast state is set to non-broadcast based on the scheduling information included in the SIB1, and Wherein, the dedicated SIB request message is sent when a common search space is configured for the active BWP and the system information broadcast state is set to non-broadcast.

12. A target special cell SpCell in a wireless communication system, the target SpCell comprising: a transceiver (510) configured to transmit and receive signals; and A controller (520) is coupled to the transceiver and configured to: performing a random access procedure with a terminal, the terminal being in a radio resource control RRC connected state with a source SpCell, and In the case where the RRC message sent from the source SpCell to the terminal is associated with a master cell group MCG and includes SIB1 and information associated with synchronization reconfiguration of the target SpCell, after the random access procedure is completed, receiving a dedicated SIB request message for a system information block SIB from the terminal, Among them, for dual connectivity, SpCell refers to the primary cell PCell of the MCG or the primary SCG cell PSCell of the secondary cell group SCG.

13. The target SpCell according to claim 12, wherein: In the case where the medium access control MAC of the MCG completes the random access procedure, the random access procedure is completed, and The information associated with synchronous reconfiguration includes information about a timer used for the corresponding SpCell.

14. The target SpCell according to claim 12, wherein: The dedicated SIB request message is received in case no common search space is configured for an active bandwidth part (BWP) and the terminal does not store a valid version of the SIB.

15. The target SpCell according to claim 12, wherein: In a case where a common search space is configured for an active bandwidth part BWP and a system information broadcast status included in the SIB1 is set to not broadcast, the dedicated SIB request message is received.

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