Systems and methods for handling small data transmission and multicast

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose methods and systems for handling Small Data Transmissions (SDTs) along with New Radio Multicast Broadcast Service (NR MBS) multicast service reception, wherein the UE has multicast MRBs configured in the RRC_INACTIVE state and / or UE can receive the multicast service in the RRC_INACTIVE state.

Description

SYSTEMS AND METHODS FOR HANDLING SMALL DATA TRANSMISSION AND MULTICAST

[0001] Embodiments disclosed herein relate to wireless communication networks, and more particularly to systems and methods for handling Small Data Transmission (SDT) and Multicast for the UE.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] NR MBS services can refer to multicast services where intended common contents are targeted to a group of User Equipments (UEs), which have joined the multicast group in the multicast coverage area and to broadcast services where intended contents may be targeted to all the UEs in the broadcast coverage area. This coverage area can be one radio cell or larger.

[0009] Specifically, multicast services refer to services being transmitted and availed by a set of UEs registered to a group; for example, a Mission Critical Push-To-Talk (MCPTT) service. Broadcast services refer to services being transmitted and available to all the UEs in a specific coverage area where the broadcast is performed and typically, the UE need not be registered. As there is one transmitter and multiple recipients, effectively, both multicast and broadcast services are Point-To-MultiPoint (PTM) services. It is also possible to provide multicast and / or broadcast services in a Point-to-Point (PTP) manner, wherein there are multiple PTP connections to share the same MBS service with multiple recipients. Apart from Multicast and Broadcast services, there are another category of services termed as Unicast services that is meant for one recipient only, and is transmitted / received through a one to one dedicated connection between the transmitter and the receiver.

[0010] It is possible to have PTM bearers, PTP bearers or a combination of PTM and PTP bearers (or reception paths) to carry the same MBS service. A combination of PTM and PTP bearers (or reception paths) may provide a lot of features with respect to increased reliability of reception of MBS service packets, and efficient switching between these two modes of reception (when needed); for example, because of mobility, network loading conditions or based on the user request density for the reception of the MBS service and accordingly, the network may decide the delivery modes and / or switching across delivery modes. Embodiments herein may refer to a bearer configuration, which has possibly both legs of PTM and PTP termed as MBS split bearer.

[0011] In the legacy system (i.e., 3GPP Release 17 MBS), UEs could receive multicast service only in the RRC_CONENCTED state. For the purpose of informing UEs in the RRC_IDLE state or RRC_INACTIVE state about multicast session "activation", a group notification or group paging mechanism is utilized. On receiving this paging, the UE transits to RRC_CONNECTED state, and starts receiving the multicast session. However, there may also be UEs which can receive multicast session(s) in the RRC_INACTIVE state (for example,, 3GPP Release 18 MBS may consider such a scenario).

[0012] Small Data Transmission (SDT) is a procedure allowing data and / or signalling transmission, while the UE remains in RRC_INACTIVE state (i.e., without transitioning to RRC_CONNECTED state). SDT is enabled on a radio bearer basis and is initiated by the UE only if less than a configured amount of UL data awaits transmission across all radio bearers for which SDT is enabled, the downlink (DL) Reference Signal Received Power (RSRP) is above a configured threshold, and a valid SDT resource is available. Logical channel restrictions configured by the network while in RRC_CONNECTED state and / or in RRCRelease message for radio bearers enabled for SDT, if any, are applied by the UE during the SDT procedure.

[0013] A potential issue relates to the UEs that are capable of receiving MBS multicast service in RRC_INACTIVE state. So far in legacy multicast, service could be received only in the RRC_CONNECTED state. When such UEs avail multicast services in RRC_INACTIVE state, the RLC entities of the associated RLC bearers, when re-established due to SDT operation will pose issue; for example, loss of multicast data and lack of service continuity for multicast service.

[0014] Therefore, there is a need to address this issue and provide a solution that can overcome the shortcoming in an efficient and a reliable manner so as to enable UEs to perform SDT and multicast in the RRC_INACTIVE state.

[0015] The principal object of embodiments herein is to disclose methods and systems for handling Small Data Transmissions (SDTs) along with New Radio Multicast Broadcast Service (NR MBS) multicast service reception, wherein the UE can receive the multicast service in the RRC_INACTIVE state.

[0016] Another object of embodiments herein is to disclose methods and systems for handling RLC entities for performing re-establishment, wherein the RLC entity considers the multicast bearers not configured to be received in RRC_INACTIVE.

[0017] Another object of embodiments herein is to disclose methods and systems for handling RLC entities for performing re-establishment, wherein the RLC entity considers the multicast bearers configured to be received in RRC_INACTIVE.

[0018] Another object of embodiments herein is to disclose methods and systems for handling HARQ buffer flushing during SDT and multicast reception in the RRC_INACTIVE state.

[0019] Another object of embodiments herein is to disclose methods and systems for managing the RRC state during cell reselection, during SDT and multicast reception in the ongoing RRC_INACTIVE state.

[0020] Another object of embodiments herein is to disclose methods and systems for continuing the RRC_INACTIVE state for multicast reception, on completing the SDT.

[0021] Another object of embodiments herein is to disclose methods and systems for handling the RRC state, when the SDT is unsuccessful, during multicast reception in the RRC_INACTIVE state.

[0022] Another object of embodiments herein is to disclose methods and systems for monitoring MCCH during an ongoing SDT in the RRC_INACTIVE state.

[0023] Accordingly, the embodiments herein provide a method for handling Small Data Transmissions (SDTs) and Multicast Broadcast Service (MBS) by a User Equipment (UE) in a wireless communication network. The method comprises receiving, by the UE, a RRC message to move to an RRC_INACTIVE state, wherein RRC message is a RRCRelease with suspendConfig message including SDT configuration; and managing, by the UE, a Radio Link Control (RLC) entity for at least one RLC bearer that is not suspended, when the UE is moving to the RRC_INACTIVE state and the at least one RLC bearer is associated with a multicast MBS radio bearer (MRB).

[0024] Accordingly, the embodiments herein provide a User Equipment (UE) comprising a processor; a memory; and a communication module. The processor is coupled with the memory, and the communication module. The processor is configured to receive a RRC message to move to an RRC_INACTIVE state, wherein RRC message is a RRCRelease with suspendConfig message including SDT configuration; and manage Radio Link Control (RLC) entity for at least one RLC bearer that is not suspended during a Small Data Transmission (SDT) procedure, when the UE is moving to the RRC_INACTIVE state and the at least one RLC bearer is associated with a multicast MBS radio bearer (MRB).

[0025] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

[0026] The disclosure provides methods for handling Small Data Transmissions (SDTs) along with New Radio Multicast Broadcast Service (NR MBS) multicast service reception, wherein the UE can receive the multicast service in the RRC_INACTIVE state.

[0027] Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the following illustratory drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:

[0028] FIG. 1 depicts a wireless communication network, according to embodiments as disclosed herein;

[0029] FIG. 2 illustrates an approach for handling SDT operations (e.g. re-establishment of the RLC entities) along with multicast reception for the UEs in the RRC_INACTIVE state, according to embodiments as disclosed herein;

[0030] FIG. 3 is a flowchart depicting the process of handling Small Data Transmissions (SDTs) and Multicast Broadcast Service (MBS) by User Equipment (UE) in a wireless communication network, according to embodiments as disclosed herein; and

[0031] FIG. 4 illustrates an approach for handling SDT operations (e.g. re-establishment of the RLC entities) along with multicast MRBs in the RRC_INACTIVE state, according to embodiments as disclosed herein.

[0032] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0033] For the purposes of interpreting this specification, the definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting. The terms "comprising", "having" and "including" are to be construed as open-ended terms unless otherwise noted.

[0034] The words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "for example,," , "i.e.," are merely used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "for example,," , "i.e.," is not necessarily to be construed as preferred or advantageous over other embodiments.

[0035] Embodiments herein may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by a firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (for example,, one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0036] It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0037] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.

[0038] The embodiments herein achieve methods and systems for handling Small Data Transmissions (SDTs) along with New Radio Multicast Broadcast Service (NR MBS) multicast service reception, wherein the UE can receive the multicast service in the RRC_INACTIVE state. Referring now to the drawings, and more particularly to FIGS. 1 through 4, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0039] FIG. 1 depicts a wireless communication network. The wireless communication network 101 can be connected to at least one User Equipment (UE) 102. The UE 102, as depicted, comprises a processor 102A, a communication module 102B, and a memory 102C.

[0040] The processor 102A may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor 102A may include multiple cores and is configured to execute the instructions stored in the memory 102C.

[0041] Further, the processor 102A is configured to execute instructions stored in the memory 102C and to perform various processes. The communication module 102B is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory 102C also stores instructions to be executed by the processor 102A. The memory 102C may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory 102C may, in some examples, be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term "non-transitory" should not be interpreted that the memory 102C is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (for example,, in Random Access Memory (RAM) or cache).

[0042] In an embodiment herein, the communication module 102B includes an electronic circuit specific to a standard that enables wired or wireless communication. The communication module 102B is configured to communicate internally between internal hardware components of the UE 102 and with external devices via one or more networks.

[0043] In an embodiment herein, if the UE receives RRCRelease with suspendConfig (i.e., the UE 102 moves to an RRC_INACTIVE stage) and if the sdt-Config is configured, the processor 102A skips re-establishing the RLC entity for each RLC bearer that is not suspended in the inactive stage and pertains to at least one of the following:

[0044] a) Each RLC bearer that is associated with multicast MRBs;

[0045] b) Each RLC bearer that is associated with multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE;

[0046] c) Each downlink RLC bearer that is associated with multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE;

[0047] d) Each RLC bearer that is associated with a PTM path of multicast MRBs; and

[0048] e) Each RLC bearer that is associated with PTM path of multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE.

[0049] In an embodiment herein, if the UE 102 receives RRCRelease with suspendConfig and if the sdt-Config is configured, the processor 102A re-establishes the RLC entity for each RLC bearer that is not suspended and pertains to at least one of the following:

[0050] a) Each uplink RLC bearer that is associated with multicast MRBs;

[0051] b) Each uplink RLC bearer that is associated with multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE;

[0052] c) Each RLC bearer that is associated with multicast MRBs that are not configured and / or not indicated to be received in RRC_INACTIVE;

[0053] d) Each RLC bearer that is associated with PTP path of multicast MRBs;

[0054] e) Each RLC bearer that is associated with PTP path of multicast MRBs that are not configured and / or not indicated to be received in RRC_INACTIVE;

[0055] f) Each RLC bearer that is associated with unicast bearer that is used for receiving multicast MRBs and / or broadcast MRBs in the RRC_CONNECTED state;

[0056] g) Each RLC bearer that is associated with multicast MRBs for the UE that is not capable of receiving multicast in RRC_INACTIVE state (for example, UE capability does not indicate the support for multicast reception in RRC_IANCTIVE state); and

[0057] h) Each RLC bearer that is associated with multicast MRBs for the UE when the serving cell for the UE in RRC_INACTIVE state is not supporting multicast reception in RRC_INACTIVE state or not capable of supporting multicast (for example, served by non-MBS capable gNB).

[0058] In an embodiment herein, if the UE 102 receives a RRCRelease with suspendConfig and if the sdt-Config is configured, the processor 102A re-establishes the RLC entity for each RLC bearer that is not suspended and pertains to a signaling radio bearer (SRB) and / or a data radio bearer (DRB) that is configured for SDT.

[0059] In an embodiment herein, if the UE 102 receives a RRCRelease with suspendConfig and if the UE 102 is configured and / or indicated to receive multicast in RRC_INACTIVE state (and / or broadcast reception), the processor 102A does not reset MAC and release of default MAC Cell Group configuration for the multicast (and / or broadcast). In other words, a partial MAC reset may be performed so that the multicast reception may be continued in the RRC_INACTIVE state, while all other MAC parameters, buffers, procedures for the legacy operations (i.e., other than multicast reception in RRC_INACTIVE and / or broadcast reception) are reset.

[0060] An example of specification is provided which addresses the operational steps for the SDT and multicast in RRC_INACTIVE for the UE 102, when the UE 102 receives RRC Release with suspendConfig message as follows:

[0061] 1> if theRRCReleaseincludessuspendConfig:

[0062] 2> reset MAC and release the default MAC Cell Group configuration, if any;

[0063] 2> apply the receivedsuspendConfigexcept the receivednextHopChainingCount;

[0064] 2> if thesdt-Configis configured:

[0065] 3> for each of the DRB in thesdt-DRB-List:

[0066] 4> consider the DRB to be configured for SDT;

[0067] 3> ifsdt-SRB2-Indicationis configured:

[0068] 4> consider the SRB2 to be configured for SDT;

[0069] 3> for each RLC bearer (except those associated with broadcast MRBsand multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE)that is not suspended:

[0070] 4> re-establish the RLC entity as specified in TS 38.322 [4];

[0071] 3> for SRB2 (if it is resumed) and for SRB1:

[0072] 4> trigger the PDCP entity to perform SDU discard as specified in TS 38.323 [5];

[0073] 3> ifsdt-MAC-PHY-CG-Configis configured:

[0074] 4> configure the PCell with the configured grant resources for SDT and instruct the MAC entity to start thecg-SDT-TimeAlignmentTimer;

[0075] An example of specification is provided which addresses the operational steps for the SDT and multicast in RRC_INACTIVE for the UE 102, when the UE 102 receives RRC Release with suspendConfig message as follows:

[0076] 1> if theRRCReleaseincludessuspendConfig:

[0077] 2> reset MAC and release the default MAC Cell Group configuration, if any;

[0078] 2> apply the receivedsuspendConfigexcept the receivednextHopChainingCount;

[0079] 2> if thesdt-Configis configured:

[0080] 3> for each of the DRB in thesdt-DRB-List:

[0081] 4> consider the DRB to be configured for SDT;

[0082] 3> ifsdt-SRB2-Indicationis configured:

[0083] 4> consider the SRB2 to be configured for SDT;

[0084] 3> for each RLC bearer (except those associated with broadcast MRBsand multicast MRBs)that is not suspended:

[0085] 4> re-establish the RLC entity as specified in TS 38.322 [4];

[0086] 3> for SRB2 (if it is resumed) and for SRB1:

[0087] 4> trigger the PDCP entity to perform SDU discard as specified in TS 38.323 [5];

[0088] 3> ifsdt-MAC-PHY-CG-Configis configured:

[0089] 4> configure the PCell with the configured grant resources for SDT and instruct the MAC entity to start thecg-SDT-TimeAlignmentTimer;

[0090] An example specification is disclosed herein, which addresses the operational steps for the SDT and multicast in RRC_INACTIVE for the UE 102, when the UE 102 receives RRC Release with suspendConfig message as follows:

[0091] 1> if theRRCReleaseincludessuspendConfig:

[0092] 2> reset MAC and release the default MAC Cell Group configuration, if any;

[0093] 2> apply the receivedsuspendConfigexcept the receivednextHopChainingCount;

[0094] 2> if thesdt-Configis configured:

[0095] 3> for each of the DRB in thesdt-DRB-List:

[0096] 4> consider the DRB to be configured for SDT;

[0097] 3> ifsdt-SRB2-Indicationis configured:

[0098] 4> consider the SRB2 to be configured for SDT;

[0099] 3> for each RLC bearer (except those associated with broadcast MRBs and PTM path of multicast MRBs that are configured and / or indicated to be received in RRC_INACTIVE) that is not suspended:

[0100] 4> re-establish the RLC entity as specified in TS 38.322 [4];

[0101] 3> for SRB2 (if it is resumed) and for SRB1:

[0102] 4> trigger the PDCP entity to perform SDU discard as specified in TS 38.323;

[0103] 3> ifsdt-MAC-PHY-CG-Configis configured:

[0104] 4> configure the PCell with the configured grant resources for SDT and instruct the MAC entity to start thecg-SDT-TimeAlignmentTimer;

[0105] In an embodiment herein, SDT and multicast reception in RRC_INACTIVE are not configured together for the UE 102. Further, in an embodiment, when the SDT and multicast reception in RRC_INACTIVE are configured together for the UE 102, the UE 102 does not perform the SDT and multicast reception at the same time. In an alternative embodiment, when the SDT and multicast reception in RRC_INACTIVE are configured together for the UE 102, the UE 102 can perform the SDT and multicast reception at the same time.

[0106] In an embodiment herein, when the UE 102 is operating SDT in RRC_INACTIVE state and cg-SDT-TimeAlignmentTimer expires, the processor 102A skips flushing the HARQ buffers that are used for MBS broadcast services and / or MBS multicast services reception in RRC_INACTIVE state. Further, the UE 102 continues to be in the RRC_INACTIVE state to ensure reception of multicast in RRC_INACTIVE state. The processor 102A flushes only the one of the following HARQ buffers:

[0107] a) the uplink HARQ buffers;

[0108] b) the uplink HARQ buffers that are used for SDT operation(s);

[0109] c) the uplink HARQ buffers that are used for SRBs and / or DRBs that are configured for SDT; and

[0110] d) all HARQ buffers except the HARQ buffers that are used for MBS broadcast services and / or MBS multicast services reception in the RRC_INACTIVE state.

[0111] In an embodiment herein, if the cell reselection occurs while the SDT procedure is ongoing and the UE 102 is configured and / or indicated to receive and / or receiving multicast in RRC_INACTIVE state, the UE 102 continues to be in RRC_INACTIVE state; i.e., the UE does not go to RRC_IDLE state. In an embodiment herein, SDT procedure is ongoing may be considered or represented as when timer T319a is running. In an embodiment herein, SDT procedure is considered as not ongoing, when timer T319a is expired and / or stopped.

[0112] In an embodiment herein, if the cell reselection occurs while the SDT procedure is ongoing and the UE 102 is configured and / or indicated to receive and / or receiving multicast in RRC_INACTIVE state, the processor 102A goes into RRC_IDLE state. Further, the processor 102A performs the following actions upon going to RRC_IDLE, such as, but not limited to, release of suspendConfig, discard of UE Inactive As context, stopping of all timers except T302, T320, T325, T330, T331, T400 and T430 and other actions typically performed when transiting to the RRC_IDLE state.

[0113] In an embodiment herein, the processor 102A initiates a transmission of a UE assistance information (UAI) message to indicate the availability of data, and / or signaling mapped to radio bearers (that are not configured for SDT), and the data and / or signalling are not about the MBS multicast (for example, paging response to group paging, a request for RRC state transition, a session release request, and so on).

[0114] 3> if data and / or signalling mapped to radio bearers not configured for SDT (except for pertaining to MBS multicast) becomes available during SDT (i.e. while SDT procedure is ongoing):

[0115] 2> if the UE did not transmit aUEAssistanceInformationmessage withnonSDT-DataIndicationsince the initiation of the current resume procedure for SDT:

[0116] 3> initiate transmission of theUEAssistanceInformationmessage in accordance with 5.7.4.3 to providenonSDT-DataIndication.

[0117] In an embodiment herein, the UE 102 initiates a transmission of UE assistance information (UAI) message to indicate the availability of data and / or signalling mapped to radio bearers that have not been configured for SDT. Further for MBS multicast MRBs, the availability of data and / or signalling may pertain to, for example, a paging response to group paging, a request for RRC state transition, a session release request, and so on. Further, the non-SDT-DataIndication or Multicast cause may be indicated in the UAI message. Further, a resumeCause as indicated by an upper layer is included and set according to the information received from the upper layer.

[0118] In an embodiment herein, when the UE 102 has initiated SDT procedure and is receiving MBS broadcast and / or MBS multicast in RRC_INACTIVE state, the processor 102A continues to be in RRC_INACTIVE state, upon successful completion of the SDT procedure. This is to ensure multicast reception in RRC_INACTIVE remains intact.

[0119] In an embodiment herein, when the UE 102 has initiated SDT procedure, and is receiving MBS broadcast and / or MBS multicast in RRC_INACTIVE state, the network 101 directs the UE 102 to continue to be in RRC_INACTIVE state, on successful completion of the SDT procedure (for example, via RRCRelease, RRCRelease with suspendConfig or RRCReject). In other words, the network 101 avoids directing the UE 102 to transit to RRC_IDLE and / or RRC_CONNECTED state upon completion of the SDT procedure. This is to ensure multicast reception in the RRC_INACTIVE state remains intact.

[0120] In an embodiment herein, when the UE 102 has initiated SDT procedure and is receiving MBS broadcast and / or MBS multicast in RRC_INACTIVE state, upon unsuccessful completion of the SDT procedure, the processor 102A skips transiting to the RRC_IDLE state, i.e., the UE 102 continues to remain in the RRC_INACTIVE state. This is to ensure multicast reception in the RRC_INACTIVE state remains intact. The unsuccessful completion of the SDT procedure can be due to at least one of the reasons including, but not limited to, cell re-selection, expiry of the SDT failure detection timer, a MAC entity reaching a configured maximum PRACH preamble threshold, an RLC entity reaching a configured maximum retransmission threshold, expiry of a SDT-specific timing alignment timer (while SDT procedure is ongoing over Configured Grant (CG) and the UE has not received a response from the network after the initial PUSCH transmission), and so on.

[0121] In an embodiment herein, while the SDT procedure is ongoing, if data appears in a buffer of any radio bearer not enabled for SDT except for MBS broadcast MRBs and / or MBS multicast MRBs in RRC_INACTIVE state, the processor 102A initiates a transmission of a non-SDT data arrival indication using UEAssistanceInformation message to the network 101 and, if available, includes the resume cause.

[0122] In an embodiment herein, while in RRC_IDLE, the processor 102A monitors the paging channels for CN-initiated paging. While in RRC_INACTIVE state with no ongoing SDT procedure, the processor 102A monitors paging channels for RAN-initiated paging and CN-initiated paging. While in RRC_INACTIVE state with an ongoing SDT procedure, the processor 102A may monitor paging channels for RAN-initiated paging and CN-initiated paging for the group paging for multicast session, for example, at least one of the session activation, session release, session deactivation, RRC state change, multicast configuration change, or any other notification included in the group paging message. Further, while in RRC_INACTIVE with an ongoing SDT procedure, the UE 102 (i.e., configured and / or indicated for multicast reception in RRC_INACTIVE state) may monitor paging channels for RAN-initiated paging and CN-initiated paging for the group paging for multicast session and / or MBS control channel (MCCH); for example, at least one of the session activation, session release, session deactivation, RRC state change, multicast configuration change, PTM configuration for the multicast session, or any other notification included in the group paging and / or MCCH message.

[0123] In an embodiment herein, while in RRC_INACTIVE state with an ongoing SDT procedure, the processor 102A (wherein the UE 102A has joined a multicast session) monitors the paging channels in a Paging Occasion (PO) signalled in system information (SI), such as, but not limited to, SI change indication, PWS indication, group paging for multicast session related notification, and so on.

[0124] In an embodiment herein, while in RRC_INACTIVE state with an ongoing SDT procedure, the processor 102A (wherein the UE 102A has joined a multicast session) monitors the paging channels in its own Paging Occasion (PO) for group paging for multicast session related notification. The PO for the UE is determined based on the UE ID.

[0125] In an embodiment herein, while in RRC_INACTIVE state with an ongoing SDT procedure, the processor 102A (wherein the UE 102A has joined a multicast session and is configured to receive multicast in RRC_INACTIVE state) monitors the paging channels in any Paging Occasion (PO) signalled in system information, such as, but not limited to, SI change indication, PWS indication, and group paging for multicast session related notification.

[0126] In an embodiment herein, while in RRC_INACTIVE state with an ongoing SDT procedure, the processor 102A (wherein the UE 102A has joined a multicast session and is configured to receive multicast in RRC_INACTIVE state) monitors the paging channels in its own Paging Occasion (PO) for group paging for multicast session related notification. The PO for the UE 102 can be determined based on the UE ID (identity).

[0127] FIG. 2 illustrates an approach for handling SDT operations (e.g. re-establishment of the RLC entities) along with multicast reception for the UEs in the RRC_INACTIVE state. In step 201, the UE 102 receives an RRCRelease message from the network 101 with a suspendConfig message; i.e., the RRCReleasemessage indicates that the UE 102 is to enter into RRC_INACTIVE state. On receiving the RRCRelease message from the network 101 with the suspendConfig message, in step 202, the UE 102 checks if sdt-Config has been configured. If sdt-Config has been configured, in step 203, the UE 102 considers the DRB to be configured for SDT, for each of the DRBs in the sdt-DRB list. On successfully configuring the sdt-SRB2-Indication, in step 204, the UE 102 considers the SRB2 to be configured for SDT, and the DRB to be configured for SDT. In step 205, the UE 102 re-establishes the RLC entity for each RLC bearer, except the RLC bearers associated with broadcast MRBs, and multicast MRBs that are configured and / or indicated to be received, when the UE 102 is in the RRC_INACTIVE state. The various actions in method 200 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 2 may be omitted.

[0128] FIG. 3 is a flowchart depicting the process of handling Small Data Transmissions (SDTs) and Multicast Broadcast Service (MBS) by User Equipment (UE) in a wireless communication network. In step 301, the UE 102 receives an indication from the network 101 to move to the RRC_INACTIVE state. In step 302, the UE 102 manages the RLC entity for at least one RLC bearer that is not suspended, when the UE is moving to the RRC_INACTIVE state and the at least one RLC bearer is associated with a multicast MBS radio bearer (MRB). In an embodiment herein, if the at least one RLC bearer is not suspended, the UE manages the RLC entity for the at least one RLC bearer by skipping re-establishment of the RLC entity for at least one RLC bearer that is not suspended. The at least one RLC bearer can be at least one of associated with a multicast MRB that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state; associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, when the UE is in the RRC_INACTIVE state; associated with a Point-To-MultiPoint (PTM) path of a multicast MRB; and associated with a PTM path of a multicast MRB that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state. In an embodiment herein, if the at least one RLC bearer is not suspended, the UE 102 manages the RLC entity for the at least one RLC bearer by re-establishing the RLC entity for at least one RLC bearer that is not suspended. The at least one RLC bearer can be associated with a multicast MRB that are at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state; associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, when the UE is in the RRC_INACTIVE state; associated with a Point-To-MultiPoint (PTM) path of a multicast MRB; associated with a PTM path of a multicast MRB that are at least one of configured, and indicated to receive multicast, when the UE is in the RRC_INACTIVE state; associated with at least one of a signaling radio bearer (SRB) and a data radio bearer (DRB) that is configured for SDT; associated with a unicast bearer that is used for receiving at least one of multicast, and broadcast in the RRC_CONNECTED state; associated with multicast MRBs for the UE which is not capable of receiving multicast in RRC_INACTIVE state; and associated with multicast MRBs for the UE when a serving cell for the UE in RRC_INACTIVE state is at least one of does not support multicast reception in RRC_INACTIVE state; and not capable of supporting multicast. The various actions in method 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 3 may be omitted.

[0129] FIG. 4 illustrates an approach for handling SDT operations (e.g. re-establishment of the RLC entities) along with multicast reception for the UEs in the RRC_INACTIVE state. In step 401, the UE 102 receives an RRCRelease message from the network 101 with a suspendConfig message; i.e., the RRCRelease message indicates that the UE 102 is to enter into RRC_INACTIVE state. On receiving the RRCRelease message from the network 101 with the suspendConfig message, in step 402, the UE 102 checks if sdt-Config has been configured. If sdt-Config has been configured, in step 403, the UE 102 considers the DRB to be configured for SDT, for each of the DRBs in the sdt-DRB list. On successfully configuring the sdt-SRB2-Indication, in step 404, the UE 102 considers the SRB2 to be configured for SDT, and the DRB to be configured for SDT. In step 405, the UE 102 re-establishes the RLC entity for each RLC bearer, except the RLC bearers associated with broadcast MRBs, and multicast MRBs. The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.

[0130] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0131] The embodiment disclosed herein describes methods and systems for handling Small Data Transmissions (SDTs) along with New Radio Multicast Broadcast Service (NR MBS) multicast service reception, wherein the UE can receive the multicast service in the RRC_INACTIVE state. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile deviceor any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in for example,, Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be for example,, hardware means like for example,, an ASIC, or a combination of hardware and software means, for example,, an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, for example,, using a plurality of CPUs.

[0132] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modification within the scope of the embodiments as described herein.

Claims

1.A method for handling Small Data Transmissions (SDTs) and Multicast Broadcast Service (MBS) by a User Equipment (UE) in a wireless communication network, the method comprising:receiving, by the UE, a Radio Resource Control (RRC) message to move to an RRC_INACTIVE state, wherein RRC message is a RRCRelease with suspendConfig message including SDT configuration; andmanaging, by the UE, a Radio Link Control (RLC) entity for at least one RLC bearer that is not suspended, in case that the UE is moving to the RRC_INACTIVE state and the at least one RLC bearer is associated with a multicast MBS radio bearer (MRB).2.The method, as claimed in claim 1, wherein managing the RLC entity for at least one RLC bearer that is not suspended comprises skipping re-establishment of the RLC entity for at least one RLC bearer that is not suspended, wherein the at least one RLC bearer is at least one of:associated with a multicast MRB　that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state;associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, when the UE is in the RRC_INACTIVE state;associated with a Point-To-MultiPoint (PTM) path of a multicast MRB; andassociated with a PTM path of a multicast MRB that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state.3.The method, as claimed in claim 1, wherein managing the RLC entity for at least one RLC bearer that is not suspended comprises re-establishing the RLC entity for at least one RLC bearer that is not suspended, wherein the at least one RLC bearer is at least one of:associated with a multicast MRB　that are at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state;associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, when the UE is in the RRC_INACTIVE state;associated with a Point-To-MultiPoint (PTM) path of a multicast MRB;associated with a PTM path of a multicast MRB that are at least one of configured, and indicated to receive multicast, when the UE is in the RRC_INACTIVE state;associated with at least one of a signaling radio bearer (SRB) and a data radio bearer (DRB) that is configured for SDT;associated with a unicast bearer that is used for receiving at least one of multicast, and broadcast in the RRC_CONNECTED state;associated with multicast MRBs for the UE which is not capable of receiving multicast in RRC_INACTIVE state; andassociated with multicast MRBs for the UE when a serving cell for the UE in RRC_INACTIVE state is at least one of does not support multicast reception in RRC_INACTIVE state; and not capable of supporting multicast.4.The method, as claimed in claim 1, wherein the method comprises:resetting, by the UE, Medium Access Control (MAC); andreleasing, by the UE, default MAC Cell Group configuration for at least one of a multicast; and a broadcast,on the UE receiving a RRCRelease or a RRCRelease with suspendConfig, and the UE is configured and / or indicated to receive at least one of multicast reception, and broadcast reception in RRC_INACTIVE state.5.The method, as claimed in claim 1, wherein the method comprises:not resetting, by the UE, Medium Access Control (MAC); andnot releasing, by the UE, default MAC Cell Group configuration for at least one of a multicast; and a broadcast,on the UE receiving a RRCRelease with suspendConfig and the UE is configured and / or indicated to receive at least one of multicast reception, and broadcast reception in RRC_INACTIVE state.6.The method, as claimed in claim 1, wherein the method comprises at least one of:skipping flushing, by the UE, at least one Hybrid Automatic Repeat reQuest (ARQ) (HARQ) buffer, if the at least one HARQ buffer is used for at least one of MBS broadcast services, and MBS multicast services reception in the RRC_INACTIVE state, when the UE is operating SDT in RRC_INACTIVE state and cg-SDT-TimeAlignmentTimer expires;flushing, by the UE, the uplink HARQ buffers that are used for SRBs and / or DRBs that are configured for SDT; andcontinuing, by the UE, to be in the RRC_INACTIVE state.7.The method, as claimed in claim 1, wherein the method comprises:continuing, by the UE, to be in RRC_INACTIVE state, if cell reselection occurs while a SDT procedure is ongoing, and the UE is at least one of configured, and indicated to at least one of receive multicast, and receiving multicast in the RRC_INACTIVE state.8.The method, as claimed in claim 1, wherein the method comprises:going, by the UE, into RRC_IDLE state, if cell reselection occurs while a SDT procedure is ongoing, and the UE is at least one of configured, and indicated to at least one of receive, and receiving multicast in RRC_INACTIVE state.9.The method, as claimed in claim 1, wherein the method comprises at least one of:providing, by the wireless communication network, an indication to the UE to continue in RRC_INACTIVE state, on successful completion of the SDT procedure, wherein the indication is provided with at least one of a RRCRelease with a suspendConfig message; and a RRCReject message;continuing, by the UE, to remain in RRC_INACTIVE state, on successful completion of a SDT procedure and receiving the indication from the wireless communication network, when the UE has initiated the SDT procedure and is receiving at least one of MBS broadcast, and MBS multicast in RRC_INACTIVE state; andcontinuing, by the UE, to remain in RRC_INACTIVE state, on unsuccessful completion of a SDT procedure, when the UE has initiated the SDT procedure and is receiving at least one of MBS broadcast, and MBS multicast in RRC_INACTIVE state.10.The method, as claimed in claim 1, wherein the method comprises at least one of:providing, by the wireless communication network, an indication to the UE to enter a, RRC_IDLE state, on successful completion of the SDT procedure, wherein the indication is provided with at least one of a RRCRelease message; and a RRCReject message;entering, by the UE, an RRC_IDLE state, on successful completion of a SDT procedure and receiving the indication from the wireless communication network, when the UE has initiated the SDT procedure and is receiving at least one of MBS broadcast, and MBS multicast in RRC_INACTIVE state; andentering, by the UE, an RRC_IDLE state, on unsuccessful completion of a SDT procedure, when the UE has initiated the SDT procedure and is receiving at least one of MBS broadcast, and MBS multicast in RRC_INACTIVE state.11.The method, as claimed in claim 1, wherein the method comprises:monitoring, by the UE, at least one of a paging channel for RAN-initiated paging and CN-initiated paging for the group paging for at least one of the multicast session, and an MBS control channel (MCCH), when the UE is in RRC_INACTIVE state, and there is an ongoing SDT procedure.12.The method, as claimed in claim 11, wherein the method comprises:monitoring, by the UE, paging channels in a Paging Occasion (PO) of the UE for group paging for multicast session related notification, when the UE is in RRC_INACTIVE state, and there is an ongoing SDT procedure, wherein the PO for the UE is determined based on the UE ID.13.A User Equipment (UE) comprising:a processor;a memory; anda communication module,wherein the processor is coupled with the memory, and the communication module, and is configured to:receive a RRC message to move to an RRC_INACTIVE state, wherein RRC message is a RRCRelease with suspendConfig message including SDT configuration; andmanage Radio Link Control (RLC) entity for at least one RLC bearer that is not suspended during a Small Data Transmission (SDT) procedure, when the UE is moving to the RRC_INACTIVE state and the at least one RLC bearer is associated with a multicast MBS radio bearer (MRB).14.The UE, as claimed in claim 13, wherein the processor is configured to manage the RLC entity for at least one RLC bearer that is not suspended by skipping re-establishment of the RLC entity for at least one RLC bearer that is not suspended, wherein the at least one RLC bearer is at least one of:associated with a multicast MRB　that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state;associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, in case that the UE is in the RRC_INACTIVE state;associated with a Point-To-MultiPoint (PTM) path of a multicast MRB; andassociated with a PTM path of a multicast MRB that is at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state.15.The UE, as claimed in claim 13, wherein the processor is configured to manage the RLC entity for at least one RLC bearer that is not suspended by re-establishing the RLC entity for at least one RLC bearer that is not suspended, wherein the at least one RLC bearer is at least one of:associated with a multicast MRB　that are at least one of configured, and indicated to receive multicast, when the UE is in the RRC_INACTIVE state;associated with a multicast MRB that is at least one of not configured, and not indicated to receive multicast, when the UE is in the RRC_INACTIVE state;associated with a Point-To-MultiPoint (PTM) path of a multicast MRB;associated with a PTM path of a multicast MRB that are at least one of configured, and indicated to receive multicast when the UE is in the RRC_INACTIVE state;associated with at least one of a signaling radio bearer (SRB) and a data radio bearer (DRB) that is configured for SDT;associated with a unicast bearer that is used for receiving at least one of multicast, and broadcast in the RRC_CONNECTED state;associated with multicast MRBs for the UE which is not capable of receiving multicast in RRC_INACTIVE state; andassociated with multicast MRBs for the UE when a serving cell for the UE in RRC_INACTIVE state is at least one of does not support multicast reception in RRC_INACTIVE state; and not capable of supporting multicast.

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