Management of system information block segmentation

Abstract

Some embodiments of the present disclosure provide a method for assembling a target SIB for a target service. The method receives, from a first cell on a first frequency carrier, a plurality of SIB segments of the target SIB, each of the plurality of SIB segments being associated with a corresponding value tag. The method stores a first SIB segment of the plurality of SIB segments in a memory of the UE. For each subsequent SIB segment of the plurality of SIB segments: the method determines whether a corresponding value tag of the subsequent SIB segment is the same as a corresponding value tag of the first SIB segment; and when the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment, stores the subsequent SIB segment in the memory of the UE. The method then assembles the target SIB using the stored plurality of SIB segments.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 032,490, entitled “SYSTEM INFORMATION BLOCK SEGMENTATION MANAGEMENT MECHANISM” and filed on May 28, 2021, and having attorney docket number US81520 (hereinafter the “US81520 Application”), the contents of which are hereby fully incorporated by reference into this disclosure. TECHNICAL FIELD

[0003] The present disclosure relates generally to wireless communications, and more particularly, to management of system information block (SIB) segmentation for user equipment (UE) in next generation wireless networks. BACKGROUND

[0004] With the huge growth in the number of connected devices and rapid increase in user / network traffic, various efforts have been made to improve different aspects of wireless communications for next generation wireless communication systems, such as the 5th Generation (5G) New Radio (NR), by increasing data rates, latency, reliability, and mobility. The 5G NR systems are designed to provide flexibility and configurability to optimize network services and types to accommodate different use cases, such as enhanced Mobile Broadband (eMBB), massive Machine-Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC).

[0005] According to the Third Generation Partnership Project (3GPP) NR, system information (or system information blocks (SIBs)) can relay many control information to UEs. For example, an emergency related message (e.g., an earthquake message) that can be transmitted to several UEs can contain many different pieces of information that must be transmitted to the UEs. Due to the large amount of information, a cell (e.g., associated with a base station) can divide or segment the data of a SIB into different groups or segments, referred to as SIB segments. As one example, for NR Vehicle-to-Everything (V2X) services, one or more base stations (e.g., gNBs) in a NR-Radio Access Network (NR-RAN) can divide system information (SI) associated with NR V2X services (and / or LTE V2X services) into several smaller SIB segments. For example, a SIB12 for V2X services can be divided (e.g., by one or more serving cells) into two or more SIB12 segments. Then, a UE interested in V2X services can store all different SIB segments transmitted by the UE’s serving cell. Once all segments of a target SIB (e.g., SIB12) are successfully received and stored, the UE can attempt to assemble the complete / target SIB.

[0006] Further, a serving cell can also broadcast other data associated with each segment of a SIB, such as other parameters. Data associated with each SIB segment, such as a segment number (e.g., an integer in the range of 0 to 63), a segment type (e.g., an enumerator further indicating whether the corresponding SIB segment is the last SIB segment), and the like, can identify the corresponding segment. Based on such received (or configured) identification data, a UE can be able to assemble a target SIB. Taking V2X services as an example, a UE can implement access stratum configuration of PC5 and Uu interfaces based on a received complete / target V2X-SIB. However, to assemble a target SIB based on received SIB segments, a UE does not check the validity of a SIB segment when receiving and storing the segment. To increase the efficiency of SIB segment management, it is desirable to check the validity of each segment of a target SIB before a SIB assembly procedure can be triggered for the target SIB. SUMMARY

[0007] The present disclosure relates to management of small data transmission by a user equipment (UE) when the UE is in an RRC_INACTIVE state.

[0008] In a first aspect of the application, a method is provided for assembling, by a user equipment (UE), a target system information block (SIB) for a target service. The method comprises receiving, from a first cell on a first frequency carrier, a plurality of SIB segments of the target SIB, each of the plurality of SIB segments being associated with a corresponding value tag, and storing a first SIB segment of the plurality of SIB segments in a memory of the UE. For each subsequent SIB segment of the plurality of SIB segments: the method determines whether the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment; and stores the subsequent SIB segment in the memory of the SIB when the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment. The method then assembles the target SIB using the stored plurality of SIB segments.

[0009] Embodiments of the first aspect further comprise, prior to successful assembly of the target SIB: selecting, by the UE, a second cell on the first frequency carrier; and discarding, after selecting the second cell, SIB segments of the stored plurality of SIB segments.

[0010] In another embodiment of the first aspect, the first frequency carrier comprises a serving frequency carrier for the UE, and the first cell and the second selected cell are serving cells of the UE.

[0011] In another embodiment of the first aspect, the first frequency carrier comprises a non-serving frequency carrier for the UE, and the first cell and the second cell are not serving cells of the UE.

[0012] In another embodiment of the first aspect, when the corresponding value tag of the subsequent SIB segment is not the same as the corresponding value tag of the first SIB segment: storing the subsequent SIB segment in the memory of the UE; and removing the first SIB segment and all previously stored SIB segments having the same value tag as the first SIB segment from the memory.

[0013] In another implementation form of the first aspect, further comprising: after successfully assembling the target SIB, if the target SIB is associated with a first areascope information element (IE), configuring a validity area of the target SIB with a first area identity (ID), wherein both the first areascope IE and the first area ID are broadcast by the first cell; selecting, by the UE, a second cell on the first frequency carrier, the second cell broadcasting a second areascope IE and a second area ID associated with a second SIB, the second SIB being configured by the second cell to support the same target service; and determining that the target SIB stored during selection of the second cell is still valid if the second area ID is the same as the first area ID associated with the target SIB. It should be noted that in some implementation forms, after selecting the second cell, the UE can check the area ID (e.g., if the area associated with the target SIB = 'true' in the first cell and / or the second cell) and the value tag broadcast by the first cell and the second cell for validity check of the same target SIB (or for validity check of SIB segments of the target SIB).

[0014] In another implementation form of the first aspect, further comprising: selecting, by the UE, a third cell on the first frequency carrier, the third cell broadcasting a third area ID, the third area ID being different from the first area ID associated with the target SIB; and determining that the target SIB is not valid during selection of the third cell.

[0015] In another implementation form of the first aspect, further comprising: selecting, by the UE, a third cell on the first frequency carrier, wherein the third cell does not broadcast any SIB related information supporting the same target service, or the third cell broadcasts data associated with a third SIB supporting the same target service but without an associated areascope IE; determining that the target SIB stored during selection of the third cell is not valid.

[0016] In a further implementation form of the first aspect, further comprising: after successfully assembling the target SIB, if the target SIB is not associated with any areascope information element (IE) transmitted by the first cell (e.g., the valid area associated with the target SIB is the downlink coverage of the serving cell from which the UE obtains the target SIB), configuring the downlink coverage of the first cell as the valid area associated with the target SIB on the UE. The downlink coverage of the serving cell can be decided based on downlink reference signal received power (DL-RSRP) measured by the UE, such as the location where the UE has a higher DL-RSRP measurement than a predefined DL-RSRP threshold.

[0017] In a further implementation form of the first aspect, the target service comprises a new radio (NR) sidelink communication service, and the target SIB comprises an NR sidelink radio configuration, and after reselecting another cell on the first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, implementing the NR sidelink communication service based on the NR sidelink radio configuration in the stored target SIB.

[0018] In a further implementation form of the first aspect, the target service comprises an evolved universal terrestrial radio access (E-UTRA) vehicle-to-everything (V2X) sidelink communication service, and the target SIB comprises an E-UTRA V2X sidelink radio configuration, and after reselecting another cell on the first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, the UE implements the E-UTRA V2X sidelink communication service based on the E-UTRA V2X sidelink radio configuration in the stored target SIB.

[0019] In a second aspect, a UE including one or more non-transitory computer-readable media having computer-executable instructions for assembling a target system information block (SIB) for a target service is provided. The processor is coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: receive, from a first cell on a first frequency carrier, a plurality of SIB segments of the target SIB, each of the plurality of SIB segments being associated with a corresponding value tag; store a first SIB segment of the plurality of SIB segments in a memory of the UE; for each subsequent SIB segment of the plurality of SIB segments: determine whether a corresponding value tag of the subsequent SIB segment is the same as a corresponding value tag of the first SIB segment; and when the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment, store the subsequent SIB segment in the memory of the UE; and assemble the target SIB using the stored plurality of SIB segments. BRIEF DESCRIPTION OF DRAWINGS

[0020] Aspects of the illustrative disclosure can best be understood with reference to the following detailed description when read with the accompanying drawings in which, various features are not drawn to scale and the sizes of the various features can be intentionally exaggerated for the sake of clarity and discussion.

[0021] Figure 1 is a diagram illustrating a UE state machine and state transitions of a UE according to an example embodiment of the present application.

[0022] Figures 2A-2B is a diagram illustrating transmission of different value tags and system information block (SIB) segments associated with a target SIB from a base station to a UE according to an example embodiment of the present application.

[0023] Figure 3A is a flowchart illustrating a method (or procedure) performed by a UE to assemble a target system information block (SIB) for a target service after successfully receiving different SIB segments of the target SIB from one or more serving cells according to an example embodiment of the present application.

[0024] Figure 3B is a flowchart illustrating a method (or procedure) performed by a UE to assemble a target system information block (SIB) for a target service after cell (re)selection according to an example embodiment of the present application.

[0025] Figure 4 is a block diagram of a node for wireless communication according to an example embodiment of the present application. DETAILED DESCRIPTION

[0026] The acronyms in this application are defined as follows, unless otherwise stated, the acronyms have the following meanings:

[0027] Acronyms full names

[0028] 3GPP Third Generation Partnership Project (3 rd Generation Partnership Project)

[0029] 5GC 5G Core (5G Core)

[0030] ACK Acknowledgement (Acknowledgement)

[0031] AMF Access and Mobility Management Function (Access and Mobility Management Function)

[0032] ARQ Automatic Repeat Request (Automatic Repeat Request)

[0033] AS Access Stratum (Access Stratum)

[0034] BCCH Broadcast Control Channel (Broadcast Control Channel)

[0035] BCH Broadcast Channel (Broadcast Channel)

[0036] BFR Beam Failure Recovery (Beam Failure Recovery)

[0037] BS Base Station (Base Station)

[0038] BSR Buffer Status Report (Buffer Status Report)

[0039] BWP Bandwidth Part (Bandwidth Part)

[0040] CA Carrier Aggregation (Carrier Aggregation)

[0041] CBRA Contention Based Random Access (Contention Based Random Access) CFRA Contention Free Random Access (Contention Free Random Access) CG Configured Grant (Configured Grant)

[0042] CM Connection Management

[0043] CN Core Network

[0044] C-RNTI Cell Radio Network Temporary Identifier

[0045] CS-RNTI Configured Scheduling Radio Network Temporary Identifier

[0046] CSI-RS Channel State Information Reference Signal

[0047] DCI Downlink Control Information

[0048] DRB Data Radio Bearer

[0049] DRX Discontinuous Reception

[0050] HARQ Hybrid Automatic Repeat Request

[0051] LCH Logical Channel

[0052] LCG Logical Channel Group

[0053] LCP Logical Channel Prioritization

[0054] MIB Master Information Block

[0055] MSG Message

[0056] NAS Non-Access Stratum

[0057] NG-RAN Next-Generation Radio Access Network

[0058] NW Network

[0059] Pcell Primary Cell

[0060] PCCH Paging Control Channel

[0061] PDCCH Physical Downlink Control Channel

[0062] PRACH Physical Random Access Channel

[0063] RA Random Access

[0064] RACH Random Access Channel

[0065] RAN Radio Access Network

[0066] RB Radio Bearer

[0067] Rel Release

[0068] RLC Radio Link Control

[0069] RNA RAN-based Notification Area RNTI Radio Network Temporary Identifier RRC Radio Resource Control

[0070] RSRP Reference Signal Receiving Power Scell Secondary Cell

[0071] SCG Secondary Cell Group

[0072] SCS Sub Carrier Spacing

[0073] SDT Small Data Transmission SDU Service Data Unit

[0074] SFN System Frame Number

[0075] SI System Information

[0076] SIB System Information Block

[0077] SINR Signal to Interference plus Noise Ratio SLIV Start and Length Indicator

[0078] SNPN Stand-alone Non-Public Network SR Scheduling Request

[0079] SRB Signaling Radio Bearer

[0080] SSB Synchronization Signal Block

[0081] S-TMSI SAE Temporary Mobile Subscriber Identity (SAE-Temporary Mobile Subscriber Identity)

[0082] SUL Supplementary Uplink (Supplementary Uplink)

[0083] TA Timing Advance or Time Alignment (Timing Advance or Time Alignment)

[0084] TS Technical Specification (Technical Specification)

[0085] UE User Equipment (User Equipment)

[0086] UL Uplink (Uplink)

[0087] UPF User Plane Function (User Plane Function)

[0088] The following description includes specific information relating to example embodiments in the present disclosure. The drawings in the present disclosure and their accompanying descriptions only relate to embodiments. However, the present disclosure is not limited to these example embodiments. Other variations and embodiments of the present disclosure will occur to those skilled in the art. Unless otherwise stated, identical or corresponding elements in the drawings can be indicated by identical or corresponding reference numerals. Also, the drawings and illustrations in the present disclosure are generally not drawn to scale, and are not intended to correspond to actual relative sizes.

[0089] For consistency and ease of understanding, like reference numerals can identify like features throughout the example figures (although in some examples not shown). However, features of different embodiments can be different in other respects as well, and thus should not be limited to what is shown in the figures.

[0090] The phrase "in an embodiment," or "in some embodiments," as used herein can each refer to one or more of the same or different embodiments. The term "coupled" is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The use of the term "include," as well as other forms such as "includes" or "including," means "including, but not limited to," and is intended to cover also not only members of the group, but also equivalents and other members of the group. The expression "at least one of A, B, and C," or "at least one of the following: A, B, and C," means "A alone, B alone, C alone, or any combination of A, B, and C."

[0091] Additionally, for purposes of explanation and non- limitation, specific details are set forth, such as particular algorithms, techniques, protocols, standards, etc. in order to provide a thorough understanding of the described technology. In other instances, detailed descriptions of well-known methods, techniques, systems, architectures, etc. are omitted so as not to obscure the description of the described technology with unnecessary detail.

[0092] Those skilled in the art will immediately appreciate that any of the network functions or algorithms described in the present disclosure can be implemented by hardware, software, or a combination of software and hardware. The described functions can correspond to modules, which can be software, hardware, firmware, or any combination thereof. Software implementations can include computer- executable instructions stored on a computer-readable medium such as a memory or other type of storage device. For example, one or more microprocessors or general purpose computers with communication processing capabilities can be programmed with the corresponding executable instructions and perform the described network functions or algorithms. These microprocessors or general purpose computers can be formed by application specific integrated circuits (ASICs), programmable logic arrays, and / or using one or more digital signal processors (DSPs). While several example implementations described in this specification are directed to software installed and executed on computer hardware, alternative example implementations implemented as firmware or hardware or a combination of hardware and software are within the scope of the present disclosure.

[0093] Computer-readable media includes, but is not limited to, random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, compact disc read only memory (CD-ROM), digitally recorded media, magnetic tape, magnetic disk storage or any other medium that can be used to store computer readable instructions.

[0094] A radio communication network architecture (e.g., a Long Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR radio access network (RAN)) typically includes at least one base station, at least one UE, and one or more optional network elements that provide connectivity to a network. The UE communicates with the network (e.g., a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), a 5G Core (5GC), or the Internet) through the RAN established by one or more base stations.

[0095] It should be noted that, in the present application, a UE can include, but is not limited to, a mobile station, a mobile terminal or device, a user communication radio terminal. For example, a UE can be a portable radio equipment including, but not limited to, a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a Personal Digital Assistant (PDA) with wireless communication capabilities. The UE is configured to receive signals over an air interface and to transmit signals to one or more cells in a radio access network.

[0096] A base station can be configured to provide a communication service in accordance with at least one of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM), commonly referred to as 2G, Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN) for GSM evolution, General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS), commonly referred to as 3G, based on basic wideband-code division multiple access (W-CDMA), High-Speed Packet Access (HSPA), LTE, LTE-A, eLTE (Evolved LTE, e.g. LTE connected to 5GC), NR, commonly referred to as 5G, and / or LTE-A Pro. However, the scope of the present application should not be limited to the previously mentioned protocols.

[0097] A base station can include, but is not limited to, a Node B (NB) in UMTS, an evolved Node B (eNB) in LTE or LTE-A, a Radio Network Controller (RNC) in UMTS, a BS Controller (BSC) in GSM / GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN), a Next Generation (NG)-eNB in an Evolved Universal Terrestrial Radio Access (E-UTRA) BS connected to 5GC, a Next Generation Node B (gNB) in a 5G-RAN, and any other apparatus that can control a radio communication and manage radio resources in a cell. The BS can be connected by a radio interface to serve one or more UEs.

[0098] A base station can be operable to provide radio coverage to a particular geographic area using a plurality of cells included in a RAN. The BS can support operation of the cells. Each cell can be operable to serve at least one UE within its radio coverage. In particular, each cell (often referred to as a serving cell) can provide service to serve one or more UEs within its radio coverage (e.g., each cell schedules downlink and optional uplink resources to at least one UE within its radio coverage for downlink and optional uplink packet transmissions). The BS can communicate with one or more UEs in a wireless communication system through a plurality of cells.

[0099] A cell can allocate sidelink (SL) resources for supporting Proximity Service (ProSe) or Vehicle to Everything (V2X) service. Each cell can have an overlapping coverage area with other cells. In a multi-RAT dual connectivity (MR-DC) case, a primary cell of a master cell group (MCG) or a secondary cell group (SCG) can be referred to as a special cell (SpCell). A primary cell (PCell) can refer to the SpCell of the MCG. A primary SCG cell (PSCell) can refer to the SpCell of the SCG. The MCG can refer to a serving cell group associated with a master node (MN), including the SpCell and optionally one or more secondary cells (SCells). The SCG can refer to a serving cell group associated with a secondary node (SN), including the SpCell and optionally one or more SCells.

[0100] As previously described, the frame structure for NR supports flexible configurations for accommodating various next generation (e.g., 5G) communication requirements, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC), while meeting high reliability, high data rate, and low latency demands. Orthogonal frequency division multiplexing (OFDM) technology agreed in 3GPP can be used as a baseline for the NR waveform. Scalable OFDM numerology, e.g., adaptive subcarrier spacing, channel bandwidth, and cyclic prefix (CP), can also be used. In addition, two coding schemes are considered for NR: (1) low density parity check (LDPC) code and (2) polar code. Coding scheme adaptation can be configured based on channel conditions and / or service applications.

[0101] In addition, it is also considered that in a transmission time interval TX of a single NR frame, at least downlink (DL) transmission data, a guard period, and uplink (UL) transmission data should be included, where each portion of the DL transmission data, the guard period, and the UL transmission data should also be configurable, e.g., based on NR network dynamics. In addition, sidelink resources can also be provided in the NR frame to support ProSe services, (E-UTRA / NR) sidelink services, or (E-UTRA / NR) V2X services.

[0102] In addition, the terms "system" and "network" can be used interchangeably herein. The term "and / or" herein is only used to describe associated objects, which can mean that there are three relationships. For example, A and / or B can mean that A exists alone, A and B exist together, or B exists alone. In addition, the character " / " herein generally represents that the previous associated object and the next associated object are in an "or" relationship.

[0103] As noted above, next generation (e.g., 5G NR) wireless networks are envisioned to support more capacity, data, and services. A UE configured with multiple connectivity can be connected to a master node (MN) as an anchor and one or more secondary nodes (SN) for data transfer. Each of these nodes can be formed by a cell group including one or more cells. For example, the MN can be formed by a master cell group (MCG), and the SN can be formed by a secondary cell group (SCG). In other words, for a UE configured with dual connectivity (DC), the MCG is a set of one or more serving cells including a PCell and zero or more secondary cells. In contrast, the SCG is a set of one or more serving cells including a PSCell and zero or more secondary cells.

[0104] As also noted above, a primary cell (PCell) can be an MCG cell operating on a primary frequency where the UE performs an initial connection setup procedure or initiates a connection reestablishment procedure. In an MR-DC mode, the PCell can belong to the MN. A primary SCG cell (PSCell) can be an SCG cell where the UE performs random access (e.g., when performing a reconfiguration with synchronization procedure). In an MR-DC mode, the PSCell can belong to the SN. Depending on whether a medium access control (MAC) entity is associated with the MCG or the SCG, a special cell (SpCell) can be referred to as a PCell of the MCG or a PSCell of the SCG. Otherwise, the term special cell can refer to a PCell. A special cell can support physical uplink control channel (PUCCH) transmission and contention-based random access, and can be activated at all times. Further, for a UE in an RRC CONNECTED state not configured with CA / DC, only one serving cell (SCell) which can be a primary cell can communicate with the UE. In contrast, for a UE in an RRC CONNECTED state configured with CA / DC, a set of serving cells including the special cell and all secondary cells can communicate with the UE.

[0105] As described above, since the amount of data associated with a system information block (SIB) (e.g., SIB12, SIB13, SIB14, etc.) can not fit into one system information message (e.g., transmitted via one or more control signaling during one system information window period), one or more serving cells (e.g., associated with one or more base stations) can divide the SIB data into different segments and transmit the segments to one or more UEs via system information delivery. The serving cell(s) can also broadcast to the UEs via the SIB segment delivery, identifying other information (e.g., parameters) associated with the SIB segment corresponding segment, such as segment number, segment type (e.g., an indicator, such as the parameter LastSegment or NotLastSegment), etc. Based on this information, the UEs can assemble the complete target SIB. However, the UEs can need to check the validity of each received segment before storing the received segments (e.g., and before assembling the target SIB from the stored segments).

[0106] Accordingly, some of the embodiments of the present disclosure provide SIB segment management mechanisms for UEs to determine whether to discard, maintain, and / or update each received SIB segment before the UE assembles the corresponding target SIB (e.g., V2X-SIB) based on the stored SIB segments. In some embodiments, the UE can perform a SIB segment validity check procedure before the UE successfully assembles the complete target SIB. In some embodiments, the UE can perform the SIB segment validity check procedure with the information (e.g., parameters) associated with the SIB segment and broadcasted by the serving cell. In some embodiments, the UE can use the target service (e.g., V2X service, NR multicast broadcast service, positioning service, etc.) after successfully assembling the corresponding target service from the stored associated SIB segments.

[0107] It should be noted that although the mechanisms for managing SIB segments described above and below are primarily described for NR, the described mechanisms can equally apply to other radio access technologies (RATs), such as LTE, Narrow Band Internet-of-Things (NB-IoT), New Radio Non-Terrestrial-Network (NR NTN).

[0108] In some of the embodiments, the SIB signaling can include the same data transmitted by more than one cell in the RAN. Thus, in some embodiments, a cell can further indicate that the SIB signaling (e.g., V2X-SIB) can be area specific. The cell can make such an indication by configuring a specific parameter associated with the SIB (e.g., an area scope parameter (e.g., areaScope)) (e.g., setting the parameter areaScope = true). In addition, a system information area ID parameter (e.g., systeminformationAreaID) can be configured to be associated with the SIB (e.g., for the UE). As a result, the UE can determine whether the stored SIB is still valid (e.g., for the serving cell) after (or during) the cell (re)selection procedure by checking these parameters (e.g., valueTag, areaScope, and systeminformationAreaID) received from the serving cell(s).

[0109] The requirements described herein for the cell (re)selection operation can apply to UEs in LTE / NR RRC_INACTIVE, RRC_IDLE, and / or RRC_CONNECTED states. Thus, these different states are first described below.

[0110] Figure 1 is an RRC state transition diagram according to an example embodiment of the present application, which illustrates various RRC states and RRC transition procedures that a UE can experience within a next generation radio access network. The RRC state transition diagram 100 can include an RRC CONNECTED state 110, an RRC INACTIVE state 120, and an RRC IDLE state 130. In some embodiments, the RRC Connected state, the RRC Inactive state, and the RRC Idle state can be three RRC states independent of each other. As shown, a UE can transition between the three RRC states. The proposed mechanisms can be applied to a UE during a target SIB reception procedure independent of the RRC state of the UE (e.g., the RRC CONNECTED state, the RRC INACTIVE state, and the RRC IDLE state). In addition, the proposed mechanisms can also be applied to a UE without being affected by the state transitions between the RRC states. Figure 1

[0111] ​For example, a UE can transition from the RRC CONNECTED state 110 to the RRC INACTIVE state 120, or can transition from the RRC INACTIVE state 120 to either of the RRC CONNECTED state 110 or the RRC IDLE state 130. However, as shown in the RRC state transition diagram 100, in some implementations, a UE can not directly transition from the RRC IDLE state 130 to the RRC INACTIVE state 120. That is, in some such implementations, a UE can transition from the RRC IDLE state 130 to the RRC INACTIVE state 120 through the RRC CONNECTED state 110. In some aspects of the present implementation, a UE can also transition from the RRC CONNECTED state 110 to the RRC INACTIVE state 120 using an RRC suspend (or RRC release and suspend) procedure. Conversely, a UE can transition from the RRC INACTIVE state 120 to the RRC CONNECTED state 110 using an RRC (connection) resume procedure. Further, a UE can transition from the RRC CONNECTED state 110 or the RRC INACTIVE state 120 to the RRC IDLE state 130 using an RRC release procedure, and from the RRC IDLE state 130 to the RRC CONNECTED state 110 using an RRC setup procedure.

[0112] In some implementations, in the RRC INACTIVE state, a UE can remain CM-CONNECTED (e.g., where the UE has a signaling connection with an AMF) and can move within an area configured by the NG-RAN (e.g., an RNA) without notifying the NG-RAN. In the RRC INACTIVE state, the last serving cell (e.g., associated with a gNB) and the UE itself can maintain a UE context (e.g., a UE (inactivity) access stratum (AS) context of the UE) as well as NG connections associated with the UE to the serving AMF and UPF.

[0113] In some embodiments, the RRC_INACTIVE state can support various functions and / or features such as small data transmission (SDT), PLMN selection, SNPN selection, system information broadcast, cell reselection mobility, paging initiated by NG-RAN (RAN paging), RAN-based notification area (RNA) managed by NG-RAN, DRX configured by NG-RAN for RAN paging, 5GC-NG-RAN connection established for the UE (e.g., both control / user (C / U) planes), NG-RAN determining the RNA to which the UE belongs, and the like. In some embodiments, for NR connected to a 5GC network, an identity of the UE (e.g., I-RNTI) can be used to identify the UE context in RRC_INACTIVE state. The I-RNTI can provide a reference to the UE context corresponding to the old NG-RAN node to the new NG-RAN node.

[0114] How the new NG-RAN node can resolve the old NG-RAN ID from the I-RNTI is a matter of proper configuration in the old and new NG-RAN nodes. Some typical partitioning of the 40-bit I-RNTI can include, but is not limited to, UE-specific reference, NG-RAN node address index, PLMN-specific information, and SNPN-specific information. The UE-specific reference can include a reference to the UE context within a logical NG-RAN node. The NG-RAN node address index can include information identifying the NG-RAN node that allocated the UE-specific part. The network-specific information (e.g., PLMN-specific information or SNPN-specific information) can include information supporting network sharing deployments and provide an index to the PLMN ID part of the global NG-RAN node identifier. SNPNs can include small PLMNs configured by an operator. Each SNPN can be identified by a unique SNPN identity (ID) (e.g., the identifier of the SNPN can be a combination of a PLMN ID and a NID). Configured authorization profiles can be associated with the SNPN ID.

[0115] In some implementations, the AS context for a UE in RRC_INACTIVE state can be stored when the connection is suspended (e.g., when the UE is in RRC_INACTIVE state) and can be resumed / retrieved when the connection is resumed (e.g., when the UE transitions from RRC_INACTIVE state to RRC_CONNECTED state). The suspension of the RRC connection can be initiated by the network. When the RRC connection is suspended, the UE can store the UE inactive AS context (and any related configuration received from the network) and can transition to RRC_INACTIVE state. If the UE is configured with SCG, the UE can release / suspend (all or part of) the SCG configuration when initiating the RRC connection resume procedure. The RRC message used to suspend the RRC connection can be integrity protected and ciphered. The resumption of the suspended RRC connection can be initiated by the upper layers when the UE needs to transition from RRC_INACTIVE state to RRC_CONNECTED state, or by the RRC layer to perform an RNA update, or by a RAN paging, e.g., from NG-RAN. When the RRC connection is resumed, the network can configure the UE according to the RRC connection resume procedure and based on the stored UE inactive AS context (and any related RRC configuration received from the network). The RRC connection resume procedure can re-activate the AS security and re-establish the SRB(s) and DRB(s).

[0116] In some implementations, in response to a request to resume the RRC connection, the network can perform any of the following procedures. In some implementations, in response to such a request, the network can resume the suspended RRC connection and send the UE to RRC_CONNECTED state, or can reject the request and send the UE to RRC_INACTIVE state (e.g., with a wait timer). In some other implementations, the network can directly re-suspend the RRC connection and send the UE to RRC_INACTIVE state in response to the request, or can directly release the (RRC) connection and send the UE to RRC_IDLE mode. In yet some other implementations, in response to a request to resume the RRC connection, the network can instruct the UE to initiate a NAS level resume (e.g., by sending an RRC setup message to the UE).

[0117] Further, in the RRC_INACTIVE state, an upper layer (or RRC layer) can configure a specific DRX mechanism for the UE. The UE’s controlled mobility can be based on network configuration in the RRC_INACTIVE state, and the UE can store the UE’s inactive AS context. Further, while the UE is in the RRC_INACTIVE state, the RRC layer can configure a RAN-based notification area. Further, while in the RRC_INACTIVE state, the UE can perform other functions, such as listening for short messages (e.g., short messages transmitted with P-RNTI by DCI); listening to a paging channel for CN paging (e.g., using 5G-S-TMSI) and RAN paging (e.g., using full I-RNTI); performing neighbor cell measurements and cell (re)selection; performing RAN-based notification area updates periodically and / or when moving outside a configured RAN-based notification area; and acquiring system information and sending SI requests (e.g., if configured).

[0118] In some aspects of the present embodiments, when a UE (e.g., in the RRC_Connected state) attempts to communicate on a non-serving frequency (e.g., to perform LTE / NR (V2X) sidelink communication, or sidelink discovery announcement), the UE can perform measurements on that frequency for cell selection and / or intra-frequency reselection (e.g., according to 3GPP Technical Specification (TS) 38.133 or 38.304 v16.5.0). For example, when the UE is interested in performing V2X sidelink communication on a non-serving frequency, the UE can perform measurements on that frequency or a frequency that provides inter-carrier V2X sidelink configuration for that frequency (e.g., for cell selection and / or intra-frequency reselection). If the UE detects at least one cell on the desired frequency, the UE is configured to perform sidelink operation on that frequency (e.g., when S criteria are met according to TS 36.304 v16.0.0 (or TS 38.304 v16.0.0)), the UE can consider itself to be in-coverage for sidelink operation on that frequency. Conversely, when the UE does not detect any cell on the desired frequency (e.g., S criteria are met), the UE can consider itself to be out-of-coverage for sidelink operation on that frequency. In this case, when the UE considers itself to be out-of-coverage on the non-serving frequency carrier, the UE can implement sidelink operation based on a stored sidelink pre-configuration on the non-serving frequency carrier (e.g., which can be pre-installed in a memory module of the UE).

[0119] In some embodiments, when a UE selects a cell on a non-serving frequency for sidelink communication (or V2X sidelink communication or sidelink discovery notification), the UE can perform additional intra-frequency cell reselection procedure(s) to select a better cell for sidelink operation on that frequency (e.g., according to TS 36.304 v16.0.0 (or TS 38.304 v16.0.0)).

[0120] In some embodiments, the UE can consider a carrier pre-configured for sidelink communication (or V2X sidelink communication) or a frequency pre-configured to have the highest cell reselection priority for providing inter-carrier V2X sidelink configuration (e.g., according to TS 36.304 v16.0.0 (or TS 38.304 v16.0.0)).

[0121] In some embodiments, when the frequency on which the UE is configured to perform sidelink communication is the serving frequency, the UE can use the serving cell on that frequency for sidelink operation.

[0122] As mentioned above, a UE can determine whether a stored target SIB (e.g., for a serving cell) is still valid after (or during) a cell (re)selection procedure by checking one or more parameters (e.g., valueTag, areaScope, systeminformationAreaID, etc.) received from the serving cell. In some of the present embodiments, more than two cells within the same configuration area (e.g., providing the same V2X-SIB and / or providing the same system information area associated with the V2X-SIB) can also be partitioned similarly. That is, a target SIB can be partitioned into identical segments, and then the same SIB segments can be transmitted / broadcast by cells within the same configuration area. For example, in some such embodiments, (i) SIB segments broadcast by cells within the same configuration area and (ii) SIB segments having the same segmentNumber can contain identical information.

[0123] In some embodiments, each cell (e.g., among cells within the same configuration area) can be able to transmit SIB segments in different ways. For example, one or more cells (e.g., within the same system information area) can broadcast SIB segments (e.g., continuously), while one or more other cells can broadcast SIB segments after receiving a SIB request message from one or more UEs (e.g., through a 2-step random access procedure or a 4-step random access procedure). However, one or more other cells can transmit SIB segments to UEs, e.g., through UE-specific dedicated control signaling (e.g., via a RRCReconfiguration message).

[0124] In the initiation phase (e.g., when the UE receives SIB1), in some embodiments, if neither the SIB segment nor the current value of the specific parameters (e.g.: valueTag, areaScope, and / or systemInformationAreaID, which can be obtained by the UE through SIB1 reception from the serving cell on the serving frequency carrier or from the selected non-serving cell on the non-serving frequency carrier) of the target SIB are stored at the UE side, the UE can store the SIB segment(s) and the received value (or parameter / enum) of the current received downlink control signaling (e.g.: systeminformationblockType1, SIB1, etc.) from the serving cell or camped cell. In other words, if neither the SIB segment nor any of these parameters are stored during the initiation phase, the UE can store at least one of the value tag parameter, the area scope parameter, and the system information area ID parameter. In some embodiments, the valueTag can be an integer within a (predefined) range, e.g., between 0 to 31. In some embodiments, the areaScope indicator can be an enum (e.g., false, true), or alternatively, the received signaling can not transmit areaScope in SIB1. In some embodiments, the systemInformationAreaID can be a bit string (e.g., with up to 24 bits), or alternatively, the systemInformationAreaID can not be present (e.g., in the received signaling).

[0125] In some embodiments, the Public Land Mobile Network (PLMN) can also be considered as supporting information in SIB segment management. Thus, in the initiation phase, when the UE starts storing the SIB segment received from the serving cell (e.g., when the serving cell is a Non-Public Network (NPN) only cell), the UE can also store the first PLMN-Identity in the PLMN-IdentityInfoList. In some embodiments, when the UE starts storing the SIB segment received from the serving cell, the UE can store the first NPN-Identity in the NPN-IdentityInfoList.

[0126] In some embodiments, a cell that can only be used for normal service for NPN users can be referred to as an NPN-only cell. An NPN-capable UE can determine that a cell is an NPN-only cell by determining that the cellReservedForOtherUse IE is set to true (e.g., when the npn-IdentitylnfoList IE is present in the CellAccessRelatedlnfo). A non-NPN-only cell can include a cell that is not an NPN-only cell. In some embodiments, a first NPN identity can include a PLMN identity and / or a network identity (NID), which can be referred to as a standalone NPN (SNPN). A first NPN identity can include a PLMN identity and / or a cell access group (CAG) identity, which can be referred to as a PNI-public network integrated (PNI-Public Network Integrated, PNI-NPN).

[0127] In some aspects of the present embodiments, in certain cases, the UE can need to check the validity of the stored SIB segments. For example, the UE can perform a SIB segment validity check procedure whenever the UE receives a SIB segment (e.g., before the SIB segment can be assembled into a complete target SIB). Checking the validity of the SIB segments can occur when the UE stays in the same coverage area (e.g., provided by the same cell), or can occur when the UE moves from one coverage area (e.g., of a first cell) to another coverage area (e.g., of a second cell).

[0128] I. Under the same coverage area of a serving cell

[0129] In some embodiments, the UE can remain under the same coverage area of the same serving cell while collecting the SIB segments of the target SIB (e.g., on the selected carrier frequency). In other words, the stored SIB segments and the storage information associated with the stored SIB segments can also be associated with an identity of the serving cell (e.g., the cellidentity parameter of the serving cell). The UE can obtain the parameter cellidentity from the serving cell by reading the broadcast system information (e.g., received via SIB1). In some embodiments, the UE (e.g., the RRC entity of the UE) can forward the cellidentity parameter to an upper layer of the UE (e.g., to the non-access stratum (NAS) layer).

[0130] In some embodiments, the UE can discard the stored SIB segments if one or more of the following conditions are met. For example, the UE can discard (e.g., remove / release from memory) the stored SIB segments (e.g., SIB segments with the initial valueTag value) if the value of the valueTag parameter received in association with the SIB segments is different from the currently stored (or configured) value of the valueTag parameter of the corresponding SIB (e.g., V2X-SIB). In some other embodiments, instead of or in addition to the value tag, the UE can discard the currently stored SIB segments if the value (e.g., whether present or not) of the areaScope parameter and / or the value (e.g., whether present or not) of the systemInformationAreaID parameter from the latest DL control signaling (e.g., SIB1) is different from the currently stored values of the areaScope and / or systemInformationAreaID parameters of the associated SIB (e.g., V2X-SIB).

[0131] For example, the UE can initially store the valueTag associated with one or more received SIB segments. Subsequently, the UE can receive a different valueTag associated with the same target SIB from the UE’s serving cell. The value tag of the same target SIB can change for different reasons. For example, the value tag can change when the serving cell modifies the target SIB before the UE is able to assemble the complete target SIB based on the stored SIB segments (e.g., when the UE receives SIB segments and valueTag from the same serving cell). In some embodiments, the received valueTag can be greater than the stored valueTag or can be less than the stored valueTag. However, when the received valueTag is different, the UE can discard (e.g., remove or release from memory) all previously stored SIB segments and then store the latest SIB segments received from its serving cell (e.g., all SIB segments are associated with the newly received valueTag). It should be noted that even when the valueTag is updated, other parameters such as areaScope and / or systemInformationAreaID can also be updated, the UE can discard the stored segments regardless of the changes in these parameters (e.g., the UE can not check to determine whether the values of these additional parameters have also changed).

[0132] Figures 2A-2B is a diagram illustrating the transmission of different value tags and SIB segments associated with a target SIB from a base station to a UE according to an example embodiment of the present application. More specifically, Figures 2A-2BIt is shown how the base station 210 (or the cell 205 associated with the base station 210) can transmit two value tags (e.g.: value tag (y) and value tag (z)) and three different segments associated with SIBx (e.g.: SIB12) to the UE 220 in five different operational stages 201-205, and how the UE 220 can perform a SIB segment validity check procedure to determine the validity of the received SIB segments.

[0133] In stage 201, the UE 220 can receive (or be configured with) a first value tag (e.g.: value tag (y)) by the base station 210. The first value tag (y) can be associated with the target SIBx. The UE can receive this value tag / areaScope / systemInformationAreaID from the base station through DL control signaling (e.g.: through RRC signaling, such as a RRCReconfiguration message with an information element “dedicatedSIB1-Delivery” configured to transmit SIB1 to the UE via UE-specific RRC signaling). Note also that this field has the same value as the corresponding configuration in broadcast (SIB1) or has the same value through SI broadcast (e.g.: SIB1).

[0134] In stage 202, the base station 210 (or cell 205) can transmit (e.g.: broadcast) a first SIB segment of SIBx (e.g.: SIBx, SEG1). The UE 220 can determine that the first SIB segment (e.g.: SEG1) is valid and can thus store this SIB segment (e.g.: in the UE’s memory) since there is no stored SIB segment for this target SIB and since the value tag of this segment is still valid (e.g.: VT(y)). Next, in stage 203, the base station 210 can transmit a second SIB segment of SIBx (e.g.: SIBx, SEG2). The UE 220 can determine that the second SIB segment (e.g.: SEG2) is also valid and can thus store this second SIB segment in the UE’s memory since the value tag of this second SIB segment is the same as the value tag associated with the stored SIB segment (e.g.: it is still VT(y)).

[0135] In stage 204, the UE 220 can receive (or be configured with) a second value tag (e.g.: value tag (z)) by the base station 210. The second value tag (z) can also be associated with the target SIBx (e.g.: the value tag can change since the SIB version can have been updated at this time). The UE 220 can receive this new value tag from the base station through DL control signaling (e.g.: through RRC signaling) or through SI broadcast (e.g.: SIB1). Figure 2B In stage 204, the UE 220 can receive (or be configured with) a second value tag (e.g.: value tag (z)) by the base station 210. The second value tag (z) can also be associated with the target SIBx (e.g.: the value tag can change since the SIB version can have been updated at this time). The UE 220 can receive this new value tag from the base station through DL control signaling (e.g.: through RRC signaling) or through SI broadcast (e.g.: SIB1).

[0136] Next, in stage 205, the base station 210 can transmit a third SIB segment of SIBx (e.g., SIBx, SEG3). However, at this stage, the UE 220 of some embodiments can determine that the value tag associated with this third SIB segment (e.g., VT(z)) is different from the value tag associated with the currently stored SIB segments (e.g., VT(y)). Thus, in some embodiments, the UE 220 can discard the stored SIB segments (e.g., SEG1 and SEG2) by removing them from its memory, and instead can store the received third SIB segment (e.g., SEG3) (e.g., and any subsequently received SIB segments associated with the same value tag (e.g., VT(z))) in the UE’s memory.

[0137] In some embodiments, the UE can also store the parameters {areaScope = true} and {systemInformationAreaID} associated with the stored SIB segments. Thereafter, the UE can receive a different {systemInformationAreaID} from the serving cell. In such a case, the UE can discard all stored SIB segments, and store the latest SIB segments received from its serving cell. It should be noted that in this case, the {valueTag} associated with the obtained (or new) SIB segments can (or can not) be updated by the UE based on the latest DL control signaling.

[0138] In some embodiments, the UE can store the parameters {areaScope = true} and {systemInformationAreaID} associated with the stored SIB segments. However, later the UE can not receive {areaScope = true} from the serving cell (e.g., areaScope can not be present in the signaling received from the serving cell). In this case, the UE can discard all stored SIB segments, and can store the latest SIB segments received from its serving cell. It should be noted that in this case, the {valueTag} associated with the obtained (or new) SIB segments can (or can not) be updated by the UE based on the latest DL control signaling.

[0139] In some implementations, when the parameter {areaScope} is absent, it means that the stored SIB segments received from the original serving cell are not area-specific, and thus, the UE can not store any {systemInformationAreaID} parameters associated with the stored SIB segments. Although the parameter {areaScope} can be absent, the UE can still receive the parameter {areaScope = TRUE} for {systemInformationAreaID}, e.g., from the latest DL control signaling. If this happens, the UE can discard all stored SIB segments, and can store the latest SIB segment(s) received from its serving cell. It should be noted that in this case, the parameter {valueTag} associated with the obtained (or newly received) SIB segment can (or can not) be updated by the UE based on the latest DL control signaling.

[0140] In some implementations, the UE can (re)select a serving cell on a target frequency associated with a particular service (e.g., a V2X service) (e.g., such that the cellidentity parameter received from the new serving cell can be different from the stored cellidentity parameter associated with the stored SIB segments), and the parameter {areaScope} can be absent in the stored SIB segments. In this case, the UE can discard all stored SIB segments that have their corresponding stored {PLMN-Identity or NPN-Identity}, {valueTag}, {areaScope} (if present), and {systemInformationAreaID} (if present) associated with the stored SIB segments. The UE can then attempt to re-obtain / store the SIB (or SIB segments) associated with the target service (e.g., V2X-SIB) received from the new serving cell.

[0141] It should be noted that in some implementations, the serving cell for the target service can not be a primary cell or a primary secondary cell or a secondary cell of the UE. Furthermore, the serving cell can not be a cell that the UE can maintain and / or a cell through which the UE can initiate an RRC connection in the serving RAN.

[0142] In some embodiments, after successfully collecting and storing all SIB segments associated with the target SIB, the UE can start assembling the complete target SIB. After assembling the target SIB, in some of the present embodiments, the UE can also re-map the stored parameters such as {valueTag}, {areaScope} (if present), {systemInformationAreaID} (if present), cell identity, and / or {PLMN-Identity or NPN-Identity} to be associated with the assembled target SIB.

[0143] In some embodiments, the UE can not consider the stored SIB segments as valid versions associated with the target SIB until the UE has assembled the complete target SIB based on the stored SIB segments. In this way, the UE can still be allowed to request the target SIB through, for example, a random access procedure (2-step and / or 4-step random access procedure) before the UE has assembled the complete target SIB. Furthermore, for an RRC connected UE, the UE can be allowed to request the target SIB through UE-specific control signaling (e.g., based on a configuration received from the serving cell).

[0144] II. Under the coverage area of multiple cells

[0145] Some aspects of the present embodiments can further represent the UE and / or RAN behavior during (or after) the cell reselection procedure and when the stored SIB segments are associated with a particular systemInformationAreaID. In such cases, in some embodiments, the UE can store and assemble SIB segments received from different cells if the same SIB (e.g., and the same SIB segment approach) is used within the cell (e.g.: a cell providing the same systemInformationAreaID in the DL control signaling for the target SIB).

[0146] In some embodiments, the UE can retain the stored SIB segments after triggering a cell (re)selection procedure for a target service (e.g.: a V2X service) (or when triggering an intra- / inter-frequency / inter-RAT / inter-system cell (re)selection procedure). In some such embodiments, the UE can check the validity of the SIB segments after the cell (re)selection procedure (or after receiving the SIB1 / SIB segments from the (intra- / inter-frequency / inter-RAT / inter-system) neighboring / target cell).

[0147] In some embodiments, upon receiving a new SIB segment, if the associated {areaScope} of the stored segment is stored, and the ({valueTag}, {systemInformationAreaID}) of the stored SIB segment is the same as the ({valueTag}, {systemInformationAreaID}) of the received SIB segment, the UE can determine that the stored SIB segment is still valid. The UE can receive system information from the serving (or target / neighbor or newly selected) cell (e.g., by reading the si-Schedulinglnfo of the SIB1 broadcast by the serving (or target / neighbor or newly selected) cell).

[0148] In addition, the UE can attempt to receive other SIB segments by listening to broadcast system information from the newly selected serving cell. In such cases, the UE can assemble a complete target SIB by combining SIB segments received from two or more selected serving cells.

[0149] Conversely, if the UE determines that the stored SIB segment is not valid for the current serving cell, the UE can discard the stored SIB segment (and the stored information associated with the stored SIB segment). For example, if the ({valueTag}, {systemInformationAreaID}) of the stored SIB segment is different from the ({valueTag}, {systemInformationAreaID}) of the received system information, the UE can discard the stored SIB segment, and subsequently store the SIB segment received from the newly selected serving cell (and the information associated with the stored SIB segment).

[0150] In some embodiments, the PLMN can also be included as part of the information of the area-specific SIB segment. In some such embodiments, the UE can also record the SIB segment associated with the parameter PLMN-Identity, which can also be provided by the same serving cell that broadcasts the SIB segment.

[0151] During the SIB segment validity check procedure, if the serving cell is a non-NPN only cell and the first PLMN-identity included in the PLMN-IdentityInfoList and the PLMN-identity associated with the stored SIB segment are the same and the {valueTag} and {systemInformationAreaID} provided by the serving cell are also the same as the {valueTag} and {systemInformationAreaID} associated with the stored SIB segment, the UE can determine that the stored SIB segment is still valid (e.g., for the serving cell).

[0152] Additionally, if the serving cell is an NPN only cell and the first NPN-Identity included in the NPN-IdentityInfoList and the NPN-Identity associated with the stored SIB segment are the same and the {valueTag} and {systemInformationAreaID} provided by the serving cell are also the same as the {valueTag} and {systemInformationAreaID} associated with the stored SIB segment, the UE can determine that the stored SIB segment is valid for the cell.

[0153] Thus, in these cases, the UE can assemble the complete target SIB by combining SIB segments received from more than one selected serving cell and stored in the UE. Otherwise, if the UE determines that the stored SIB segment is invalid (e.g., for the serving cell), the UE can discard the stored SIB segment (and the stored information associated with the stored SIB segment). When the UE determines that the SIB segment stored at the UE is invalid, the UE can re-obtain / store the SIB segment received from a newly selected serving cell (and the information associated with the stored SIB segment).

[0154] Figure 3A FIG. 3A is a flowchart illustrating a method (or procedure) performed by a UE to assemble a target SIB for a target service after successfully receiving different SIB segments of the target SIB from one or more serving cells and storing the SIB segments, according to an example embodiment of the present application.

[0155] The procedure 300A can begin at 310 by receiving a plurality of SIB segments of a target SIB, for example, from a first cell on a first frequency carrier. As described above, in some embodiments, each of the plurality of SIB segments can be associated with a corresponding value tag that was (previously) configured to the UE.

[0156] Then, the process 300A can determine, at 320, whether there are any additional SIB segments (e.g., in a plurality of SIB segments) to process. For the first time the process is executed, since at least one segment (e.g., the first SIB segment) remains to be processed, the process can determine that a segment remains and can proceed to action 330. In action 330, the process 300A can determine whether the corresponding value tag of the currently processed SIB segment is the same as the corresponding value tag of the first SIB segment. Again, when the process is executed for the first time, the value tag of the currently processed segment (e.g., the first segment) is the same as the value tag corresponding to the first SIB segment. As such, at 340, the process can store the currently processed SIB segment in, for example, a memory of the UE. Then, the process 300A can return to action 320 to determine whether any additional SIB segments remain to be processed.

[0157] In the case where all processed segments have the same value tag as the first SIB segment and the last SIB segment has also been successfully processed, the process 300A can proceed to action 350 to assemble the target SIB using the stored plurality of SIB segments. However, if for any processed segment before reaching the end of the plurality of segments, the process 300A determines at 330 that the value tag associated with the currently processed SIB segment is different from the value tag associated with the first SIB segment, the process can discard the currently stored segments at 360. For example, the process can remove all stored SIB segments from memory and begin storing any new SIB segments associated with the new value tag. Then, the process can end.

[0158] In some implementations, if the UE moves from a current serving cell to a second cell (e.g., by (re)selecting the second cell) during the SIB segment validity check process (e.g., while the UE stores SIB segments of a target SIB), the UE can discard all stored SIB segments upon selecting the second cell, regardless of whether the second cell is on the same frequency carrier as the first cell. In some implementations, the first frequency carrier of the first cell can comprise a serving frequency carrier for the UE, and the first cell and the second selected cell can comprise serving cells for the UE. In some other implementations, the first frequency carrier can comprise a non-serving frequency carrier for the UE, and the first cell and the second cell can not be serving cells for the UE.

[0159] In some other implementations, upon the corresponding value tag of the currently processed SIB segment being different from the corresponding value tag of the first SIB segment, the process 300A can store the currently processed SIB segment in a memory of the UE and can remove the first SIB segment and all previously stored SIB segments having the same value tag as the first SIB segment from the memory.

[0160] In some implementations, after successfully assembling the target SIB, if the target SIB is associated with a first areascope information element (IE) (e.g., when both the first areascope IE and the first area ID are broadcast by the first cell), the process 300A can configure the valid area for the target SIB with a first area identity (ID). The process 300A can then select a second cell on the first frequency carrier that broadcasts a second areascope IE and a second area ID associated with a second SIB configured by the second cell to support the same target service. If the second area ID is the same as the first area ID associated with the target SIB, the process can determine that the target SIB stored during the selection of the second cell is still valid. In some such implementations, the process 300A can select a third cell on the first frequency carrier that broadcasts a third area ID that is different from the first area ID associated with the target SIB and can determine that the target SIB is not valid during the selection of the third cell.

[0161] In some implementations, the process 300A can select a third cell on the first frequency carrier that does not broadcast any SIB related information supporting the same target service or that broadcasts data associated with a third SIB supporting the same target service but not having an associated areascope IE. The process can then determine that the target SIB stored during the selection of the third cell is not valid.

[0162] In some other implementations, after successfully assembling the target SIB, if the target SIB is not associated with any areascope information element (IE) sent by the first cell, the process 300A can configure the valid area associated with the target SIB on the UE.

[0163] In some implementations, the target service can include a new radio (NR) sidelink communication service and the target SIB can include an NR sidelink radio configuration. In some such implementations, after reselecting another cell on the first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, the process 300A can implement the NR sidelink communication service based on the NR sidelink radio configuration in the stored target SIB.

[0164] Figure 3B FIG. 3B is a flowchart illustrating a method (or process) performed by a UE to assemble a target SIB for a target service after cell (re)selection according to an example implementation of the present application.

[0165] Process 300B can check the validity of stored SIB segments (if any) by first determining whether a cell selection or cell reselection procedure has been triggered by the UE when the UE has previously stored one or more SIB segments in action 370. Such a determination can be made before the UE successfully assembles the target SIB. Then, after action 310, if process 300B determines that a cell selection / cell reselection procedure has been triggered, e.g., during the SIB segment reception procedure, and the UE has stored at least one SIB segment from a plurality of first SIB segments of the target SIB, the process can discard the stored SIB segments at 395. Conversely, the UE can keep monitoring the value tag associated with the target SIB / SIB segment (e.g., by receiving SIB1 from the serving cell). For example, in action 380, when the UE stays at the same serving cell during the SIB segment reception procedure or the UE just started receiving the SIB segment(s) of the target SIB (e.g., when the UE has not stored any SIB segment of the target SIB yet), process 300B can receive the value tag associated with the target SIB or the target SIB segment.

[0166] In action 390, process 300B can determine whether the corresponding value tag of the target SIB / SIB segment (e.g., via the currently received SIB1 transmission of the serving cell) is the same as the corresponding value tag of the stored SIB segment. Again, when process 300B is executed for the first time, the UE can store the value tag of the target SIB / SIB segment (e.g., received by the UE via the currently received SIB1) in, e.g., the memory of the UE as the value tag of the SIB segment(s). If process 300B determines that the value tag of the currently received target SIB information (in the currently received SIB1) is the same as the value tag corresponding to the stored SIB segment(s), and additional SIB segments are left to be received, process 300B can execute process 300A to receive new SIB segments. During the execution of process 300A, the UE can attempt to decode and acquire additional SIB segments during the system information (SI) window time period configured by the serving / non-serving cell (e.g., the SI window configuration can also have been transmitted in SIB1). As described above with reference to process 300A, for the first time execution of this process, the UE can receive the first SIB segment and store it in the storage module of the UE. Then, the UE can check whether all SIB segments of the target SIB have been received by the UE while checking whether the value tag changes during the SIB segment reception and before successfully receiving all segments. The above with reference to process 300A can be repeated until the UE successfully assembles the target SIB. Figure 3AActions that the UE can take next are described. It should be noted that in some embodiments, if the UE has checked the value tag associated with the target SIB / SIB segment and the value tag associated with the stored (first) SIB segment (e.g., the UE has implemented action 380 and action 390 in running process 300B, and then triggers process 300A after action 390), the UE can skip action 330 and action 360 in process 300A. It should also be noted that in this case, in running process 300A, the UE can directly store the received SIB segment in action 320 of process 300A if there is still at least one target SIB segment left.

[0167] On the other hand, if process 300B determines that the received value tag is different from the UE's current stored (or configured) value tag, the process can proceed to action 395 to discard all currently stored SIB segments of the target SIB. The process can then end. In some embodiments, the UE can obtain the scheduling information of the target SIB (e.g., the SI window period of the target SIB / SIB segment) via SIB1.

[0168] In some embodiments, if the UE moves from a current serving cell to a second cell in the same frequency carrier or a different frequency carrier (e.g., an intra-frequency cell (re)selection or an inter-frequency cell (re)selection) during the SIB segment validity check procedure (e.g., when the UE stores any SIB segment of the target SIB), the UE can discard all stored SIB segments upon selecting the second cell, regardless of whether the frequency carrier is a serving frequency carrier or a non-serving frequency carrier to the UE. In some embodiments, the first frequency carrier of the first cell can include a serving frequency carrier for the UE, and the first cell and the second selected cell can include a serving cell (e.g., a primary cell, a primary secondary cell, or a secondary cell) for the UE. In some other embodiments, the first frequency carrier can include a non-serving frequency carrier for the UE, and the first cell and the second cell can not be a serving cell for the UE.

[0169] In some embodiments, as described above, after successfully assembling the target SIB, if the target SIB is not associated with any areascope information element (IE) transmitted by the first cell, the UE can configure the downlink coverage of the first cell (the serving cell when the UE successfully assembled the target SIB) to be the valid area associated with the target SIB on the UE.

[0170] In some implementations, as described above, the target service can include a new radio (NR) sidelink communication service, and the target SIB can include an NR sidelink radio configuration. In some such implementations, upon reselecting another cell on a first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, the UE can implement the NR sidelink communication service based on the NR sidelink radio configuration in the stored target SIB.

[0171] In some implementations, when a cell changes or modifies a segment associated with a SIB (e.g., even when the full SIB remains the same), the cell can change the valueTag associated with the SIB. In some implementations, the cell can also need to initiate a system information modification procedure to change the SIB segmentation procedure (e.g., even when the full SIB remains the same). In some such implementations, when a UE receives an indication(s) of SI modification procedure due to the change in the SIB segmentation procedure, the UE can discard all stored SIB segments. Further, if the UE receives an indication(s) of SI modification procedure due to the change in the SIB segmentation procedure, the UE can also discard the stored SIB segments related to the SIB to be modified.

[0172] In some implementations, the above SI change indication can be sent by a cell in a modification period (e.g., for system information change) in a paging message (e.g., via a short message, which can be broadcasted by a serving cell in (at least) one physical downlink control channel (PDCCH)), and can not be applied to SIB segmentation change. In other words, in some implementations, when the SIB segmentation method changes, the base station can not set the SI change indication in the paging message to true (or set to equal to 1), but the content of the SIB is still the same.

[0173] In some implementations, a cell can not need to initiate a system information modification procedure to change the SIB segmentation method. Instead, the cell can directly change its valueTag and then transmit the SIB (e.g., V2X-SIB) with a different SIB segmentation method. In this condition, the UE can be responsible for checking the latest valueTag before the UE successfully assembles the full SIB from the stored SIB segments.

[0174] In some embodiments, when a cell changes the segmentation method associated with a target SIB (e.g., even when the full SIB remains the same), the cell can not change its valueTag associated with the SIB. In some other embodiments, when a cell changes the segmentation method associated with a target SIB (e.g., even when the full SIB remains the same), the cell can change the valueTag associated with the target SIB. In some embodiments, a cell can change the SIB delivery method before a UE successfully assembles the full target SIB (e.g., V2X-SIB). For example, before a UE successfully assembles the full target SIB, the cell can change its si-BroadcastStatus associated with the target SIB from {broadcasting} to {non-broadcasting}. In this case, the UE can still maintain the stored SIB segments, and then can initiate a (2-step or 4-step) random access procedure to request the target SIB again. Alternatively, the UE (e.g., in RRC CONNECTED state) can still maintain the stored SIB segments, and then transmit an RRC message (e.g., dedicatedSIBRequest message) to the serving cell to request the target SIB. Upon transmitting the RRC message (e.g., dedicatedSIBRequest message) to the serving cell, the UE can start a timer (e.g., T350 parameter in NR protocol, such as the parameter described in 3GPP TS 38.331 v16.0.0).

[0175] In some embodiments, before a UE successfully assembles the full target SIB, the UE can move from RRC IDLE / INACTIVE state to RRC CONNECTED state. Further, the UE can be allowed to request the target SIB through dedicated control signaling (e.g., even when the UE has already stored the SIB segments of the target SIB). In this way, the serving cell can send the full target SIB to the UE through UE-specific dedicated control signaling (e.g., through RRC (Connection) Reconfiguration message). In this case, the UE can be allowed to send a target SIB request message to the serving cell. Further, after the UE receives the full target SIB from the serving cell (e.g., when successfully receiving the RRC (Connection) Reconfiguration message), the UE can discard the stored SIB segments of the target SIB.

[0176] In some embodiments, after the UE moves from RRC Inactive / Idle state to RRC Connected state, the UE can still maintain the stored SIB segments. Furthermore, when the UE is requesting a target SIB, the UE can not request the full target SIB (e.g., SIB 12). Instead, the UE can only request the SIB segments that are needed by the UE to assemble the full target SIB. For example, if a serving cell broadcasts the following SIB segments: {SIB Segment #0, SIB Segment #1, SIB Segment #2, SIB Segment #3, SIB Segment #4, SIB Segment #5}, once the UE moves to RRC Connected state with the stored {SIB Segment #0, SIB Segment #2, SIB Segment #3, SIB Segment #5}, when the UE requests a target SIB from the serving cell, the UE can need to further indicate the SIB segment(s) that the UE only needs to be Segment 1 and Segment 4 by transmitting one additional information element (IE) to the serving cell: {Request SIB Segment Number = 1, 4}. After receiving such additional IE, the serving cell can simply transmit the requested SIB segments (e.g., {SIB Segment #1, SIB Segment #4}) to the UE (e.g., through RRC (Connection) Reconfiguration message).

[0177] In some embodiments, the serving cell can also indicate one additional IE to enable / disable SIB segment request (e.g.: SIB segmentRequest = {enable or disable}) that can be sent to the UE through dedicated control signaling or broadcast system information. Then, the UE can request specific SIB segments from the serving cell. Thus, if the SIB segmentRequest message is enabled, when the UE requests a target SIB from the serving cell (e.g., dedicated SIB request message), the UE can further indicate the Segment Number(s) of the SIB segments that the UE needs for the target SIB combination. Conversely, if the SIB segmentRequest message is disabled, the UE can not be able to further indicate the Segment Number(s) of the SIB segments that the UE needs.

[0178] It should be noted that the SIB segmentRequest can be transmitted by the UE to the serving cell through a 2-step random access procedure (e.g., the UE can transmit the SIB segmentRequest message in the PUSCH of the MSGA) or through a 4-step random access procedure (e.g., the UE can transmit the SIB segmentRequest message in the MSG3 or MSG5). For a UE in RRC connected state, the UE can transmit the SIB segmentRequest message to the serving cell through the UEAssistInformation or the UEsidelinkAssistanceInformation. In some additional embodiments, a bitmap can be transmitted in the SIB segmentRequest message, each bit associated with a SIB segment. Then, the UE can set bit = 1 to indicate that the UE requests the corresponding SIB segment. Otherwise, the UE can set bit = 0 to indicate that the UE does not request the corresponding SIB segment. In addition, the rightmost bit can be associated with the SIB segment of SegmentNumber = 0, while the leftmost bit can be associated with the SIB segment of segmentType = the last SIB segment.

[0179] In some embodiments, one or more errors can occur during the SIB assembly procedure. When an error occurs, the UE can reply to the serving cell with a “SIB segment assembly error event” message. In some embodiments, the UE can send the “SIB segment assembly error event” message to the serving cell through a 2-step RA procedure (e.g., through the MSGA) or a 4-step RA procedure (e.g., through the MSG3 or MSG5). In some other embodiments, the UE (e.g., a UE in RRC connected state) can send the “SIB segment assembly error event” message to the serving cell through UE-specific dedicated control signaling.

[0180] In some implementations, a timer can be disabled for the UE (e.g., the T_sib-assembly-error parameter) to restrict the UE to triggering the "SIB segment assembly error event" only after the timer expires. Therefore, when an SIB segment assembly error event occurs, the UE can trigger a timer (e.g., disable the timer) and then count down from its initial value to zero. While the timer is still running or counting, the UE may not initiate the process of sending an "SIB segment assembly error event" message to the serving cell. Alternatively, the UE can still attempt to receive and assemble the target SIB while the disabled timer is still counting. Then, after the disabled timer expires (or after the disabled timer counts to zero), the UE can initiate an SIB segment assembly error event reporting procedure and report the error to the serving cell. Furthermore, the UE can discard all stored SIB segments after the timer expires. Additionally, the initial value of the T_sib-assembly-error parameter can also be transmitted to the UE via broadcast system information or UE-specific dedicated control signaling. Furthermore, after the UE obtains the complete target SIB, the UE can stop (or release) the counting of T_sib-assembly-error. Furthermore, after the UE discards all stored SIB segments, the UE can stop (or release) the T_sib-assembly-error counter. If the UE receives a new configuration from the serving cell, the UE can reset T_sib-assembly-error.

[0181] Table 1 below includes examples of SIB and / or SIB segment validity check procedures performed by the UE.

[0182] Table 1

[0183]

[0184]

[0185] Figure 4 A block diagram of a node for wireless communication according to an exemplary embodiment of this application is shown. Figure 4 As shown, node 400 may include a transceiver 420, a processor 426, a memory 428, one or more presentation components 434, and at least one antenna 436. Node 400 may also include a radio frequency (RF) spectrum module, a base station communication module, a network communication module, a system communication management module, input / output (I / O) ports, I / O components, and a power supply (in... Figure 4 (Not explicitly shown in the text). Each of these components can communicate with each other directly or indirectly via one or more buses 440.

[0186] The transceiver 420, with transmitter 422 and receiver 424, can be configured to transmit and / or receive time and / or frequency resource partitioning information. In some embodiments, the transceiver 420 can be configured to transmit in different types of subframes and slots, including but not limited to usable, unusable, and flexibly usable subframe and slot formats. The transceiver 420 can be configured to receive data and control signaling.

[0187] Node 400 can include a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by node 400 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer-readable media can comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data.

[0188] Computer storage media includes RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media does not include a propagated data signal. Communication media typically embodies computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term "modulated data signal" means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of the any of the above should also be included within the scope of computer-readable media.

[0189] Memory 428 can include computer-storage media in the form of volatile and / or nonvolatile memory. The memory 428 can be removable, non-removable, or a combination thereof. For example, the memory can include solid-state memory, hard drives, optical drives, and the like. As shown, the memory 428 can store computer-readable, computer-executable instructions 432 (e.g., software code) configured to, when executed, cause the processor 426 (e.g., processing circuitry) to perform various functions described herein, such as with reference to Figure 4 Figures 1 to 4 Optionally, the instructions 432 can not be directly executable by the processor 426 but are configured to cause the node 400 (e.g., when compiled and executed) to perform various functions described herein. ​

[0190] The processor 426 can include an intelligent hardware device, e.g., a central processing unit (CPU) such as a microcontroller or a microprocessor, an ASIC, etc. The processor 426 can include memory. The processor 426 can process data 430 and instructions 432 received from the memory 428 and information from the transceiver 420, the baseband communication module, and / or the network communication module. The processor 426 can also process information to be sent to the transceiver 420 for transmission to the NW communication module for transmission to the CN.

[0191] The one or more presentation components 434 present data indications to a human or other device. For example, the one or more presentation components 434 include a display device, a speaker, a printing component, a vibrating component, etc.

[0192] From the foregoing description, it will be apparent that various forms of the concepts described herein can be realized. Although specific embodiments of the concepts have been described herein, it will be understood by those skilled in the art that various modifications, equivalent substitutions, and changes in form and details can be made in the concept without departing from the scope of the concept. Therefore, the described embodiments are to be considered in all respects as illustrative and not restrictive. It should also be understood that while the application is not limited to the particular embodiments described above, the many possible rearrangements, modifications, alternative compositions, and equivalent substitutions are possible in light of the above teachings.

Claims

1. A method for a user equipment (UE) to assemble a target system information block (SIB) for a target service, the method comprising: receiving, from a first cell on a first frequency carrier, a plurality of SIB segments of the target SIB, each of the plurality of SIB segments being associated with a corresponding value tag; storing a first SIB segment of the plurality of SIB segments in a memory of the UE; for each subsequent SIB segment of the plurality of SIB segments: determining whether a corresponding value tag of the subsequent SIB segment is the same as a corresponding value tag of the first SIB segment; and storing the subsequent SIB segment in the memory of the UE when the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment; and assembling the target SIB using all stored SIB segments, selecting, by the UE, a second cell on the first frequency carrier before the assembling of the target SIB is successful; and discarding all stored SIB segments after the selecting of the second cell.

2. The method of claim 1, wherein: the first frequency carrier comprises a serving frequency carrier for the UE, and the first cell and the selected second cell are serving cells of the UE.

3. The method of claim 1, wherein: the first frequency carrier comprises a non-serving frequency carrier for the UE, and the first cell and the second cell are not serving cells of the UE.

4. The method of claim 1, wherein, the method further comprising: when the corresponding value tag of the subsequent SIB segment is not the same as the corresponding value tag of the first SIB segment: storing the subsequent SIB segment in the memory of the UE; and removing the first SIB segment and all previously stored SIB segments having the same value tag as the first SIB segment from the memory.

5. The method of claim 1, wherein, the method further comprising: after successfully assembling the target SIB, if the target SIB is associated with a first area scope (areascope) information element (IE), configuring a valid area of the target SIB with a first area identity (ID), wherein both the first areascope IE and the first area ID are broadcast by the first cell; selecting, by the UE, a second cell on the first frequency carrier, the second cell broadcasting a second areascope IE and a second area ID associated with a second SIB, the second SIB being configured by the second cell to support the same target service; and determining that the target SIB stored during the selecting of the second cell is still valid if the second area ID is the same as the first area ID associated with the target SIB.

6. The method of claim 5, wherein, the method further comprising: selecting, by the UE, a third cell on the first frequency carrier, the third cell broadcasting a third area ID, the third area ID being different from the first area ID associated with the target SIB; and determining that the target SIB is not valid during the selecting of the third cell.

7. The method of claim 5, wherein, The method further includes: selecting, by the UE, a third cell on the first frequency carrier, wherein the third cell does not broadcast any SIB related information supporting the same target service, or the third cell broadcasts data associated with a third SIB supporting the same target service but not having an associated areascope IE; determining that the target SIB stored during selection of the third cell is not valid.

8. The method of claim 1, wherein, The method further includes: after successful assembly of the target SIB, if the target SIB is not associated with any area scope areascope information element IE sent by the first cell, configuring a downlink coverage of the first cell to be a valid area associated with the target SIB on the UE.

9. The method of claim 1, wherein the target service comprises a new radio, NR, sidelink communication service, and the target SIB comprises an NR sidelink radio configuration, the method further comprising: after reselecting another cell on the first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, implementing the NR sidelink communication service based on the NR sidelink radio configuration in the stored target SIB. 10.A user equipment (UE), comprising: The UE includes: one or more non-transitory computer-readable media having computer-executable instructions for assembling a target system information block, SIB, for a target service; and at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: receive, from a first cell on a first frequency carrier, a plurality of SIB segments of the target SIB, each of the plurality of SIB segments being associated with a corresponding value tag; store a first SIB segment of the plurality of SIB segments in a memory of the UE; for each subsequent SIB segment of the plurality of SIB segments: determine whether a corresponding value tag of the subsequent SIB segment is the same as a corresponding value tag of the first SIB segment; and when the corresponding value tag of the subsequent SIB segment is the same as the corresponding value tag of the first SIB segment, store the subsequent SIB segment in the memory of the UE; and assemble the target SIB using all stored SIB segments, select a second cell on the first frequency carrier before assembly of the target SIB is successful; and upon selection of the second cell, discard all stored SIB segments.

11. The UE of claim 10, wherein the first frequency carrier comprises a serving frequency carrier for the UE, and the first cell and the selected second cell are serving cells of the UE.

12. The UE of claim 10, wherein the first frequency carrier comprises a non-serving frequency carrier for the UE, and the first cell and the second cell are not serving cells of the UE.

13. The UE of claim 10, wherein, the at least one processor is further configured to execute the computer-executable instructions to: when a corresponding value tag of the subsequent SIB segment is different from a corresponding value tag of the first SIB segment: store the subsequent SIB segment in the memory of the UE; and remove the first SIB segment and all previously stored SIB segments having a same value tag as the first SIB segment from the memory.

14. The UE of claim 10, wherein, the at least one processor is further configured to execute the computer-executable instructions to: after successfully assembling the target SIB, if the target SIB is associated with a first area scope areascope information element (IE), configure a valid area for the target SIB with a first area identity (ID), wherein both the first areascope IE and the first area ID are broadcast by the first cell; select a second cell on the first frequency carrier, the second cell broadcasting a second areascope IE and a second area ID associated with a second SIB, the second SIB configured by the second cell to support the same target service; and determine that the target SIB stored during selection of the second cell is still valid if the second area ID is the same as the first area ID associated with the target SIB.

15. The UE of claim 14, wherein, the at least one processor is further configured to execute the computer-executable instructions to: select a third cell on the first frequency carrier, the third cell broadcasting a third area ID, the third area ID is different from the first area ID associated with the target SIB; and determine that the target SIB is not valid during selection of the third cell. the at least one processor is further configured to execute the computer-executable instructions to:

16. The UE of claim 14, wherein, select a third cell on the first frequency carrier, wherein the third cell does not broadcast any SIB related information supporting the same target service or the third cell broadcasts data associated with a third SIB supporting the same target service but not having an associated areascope IE; determine that the target SIB stored during selection of the third cell is not valid. the at least one processor is further configured to execute the computer-executable instructions to:

17. The UE of claim 10, wherein, after successfully assembling the target SIB, if the target SIB is not associated with any area scope areascope information element (IE) sent by the first cell, configure a downlink coverage of the first cell as a valid area associated with the target SIB on the UE.

18. The UE of claim 10, wherein the target service comprises a new radio (NR) sidelink communication service and the target SIB comprises an NR sidelink radio configuration, wherein the at least one processor is further configured to execute the computer-executable instructions to: ​ After reselecting another cell on the first frequency carrier, if it is determined that the stored target SIB is valid on the reselected cell, implementing the NR sidelink communication service based on the NR sidelink radio configuration in the stored target SIB.

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