Method and apparatus for enhanced paging in MT-SDT

Abstract

The present application relates to a method and apparatus for paging enhancement in Mobile Terminated Small Data Transmission (MT-SDT). One embodiment of the present disclosure provides a first network node, the first network node including a processor and a transceiver coupled to the processor, the processor configured to receive, via the transceiver, first information related to Mobile Terminated Small Data Transmission (MT-SDT) for a user equipment (UE) from a second network node, and determine whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node.

Description

[Technical Field]

[0001] The present disclosure relates to 3rd Generation Partnership Project (3GPP) 5G wireless communication technologies, and more particularly to methods and apparatus for paging enhancement in mobile terminating small data transmission (MT-SDT). [Background technology]

[0002] MT-SDT is a downlink (DL) triggered SDT by a paging message that does not trigger the UE to transition to the RRC_CONNECTED state.

[0003] Radio Access Network (RAN) paging messages are used to allow one Next Generation (NG)-RAN node to request paging of a UE at another NG-RAN node.

[0004] When a user equipment (UE) leaves the last serving gNB and camps on a cell controlled by another gNB within a RAN-based Notification Area (RAN), and DL small data arrives at the last serving gNB, the existing Xn RAN paging procedure cannot identify MT-SDT and therefore cannot support MT-SDT. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, it is desirable to provide a solution for RAN paging enhancement in MT-SDT. [Means for solving the problem]

[0006] One embodiment of the present disclosure provides a first network node, the first network node including a processor and a transceiver coupled to the processor, wherein the processor is configured to receive, via the transceiver, first information related to a Mobile Terminated Small Data Transmission (MT-SDT) for a user equipment (UE) from a second network node, and determine whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node.

[0007] In some embodiments, the first information is included in a RAN paging message from the second network node, or the first information is included in another message other than a RAN paging message from the second network node.

[0008] In some embodiments, the first information related to MT-SDT for the UE includes at least one of the following: a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations; a third information element indicating a first network node that decides whether to start MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start MT-SDT for the UE; or a fifth information element indicating whether the second network node sends a paging message for MT-SDT at the second network node or sends a paging message to the UE to start MT-SDT.

[0009] In some embodiments, the one or more SDT configurations include at least one of one or more data radio bearers (DRBs), one or more service types associated with the one or more DRBs, one or more quality of service (QoS) parameters, one or more signaling radio bearers (SRBs), or one or more thresholds associated with the SDT.

[0010] In some embodiments, the transceiver is further configured to transmit, to the second network node, second information indicating whether the first network node decides to start MT-SDT for the UE.

[0011] In some embodiments, the second information is included in a message for requesting the UE context from the second network node via an interface between the first network node and the second network node, or the second information is included in a message other than a message for requesting the UE context from the second network node via an interface between the first network node and the second network node.

[0012] In some implementations, the processor is further configured to determine to start MT-SDT for the UE for a duration.

[0013] Another embodiment of the present disclosure provides a method implemented by a first network node, the method including: receiving first information related to a Mobile Terminated Small Data Transmission (MT-SDT) for a user equipment (UE) from a second network node; and determining whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node.

[0014] In some embodiments, the first information is included in a RAN paging message from the second network node, or the first information is included in another message other than a RAN paging message from the second network node.

[0015] In some embodiments, the first information related to MT-SDT for the UE includes at least one of the following: a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations; a third information element indicating a first network node that decides whether to start MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start MT-SDT for the UE; or a fifth information element indicating whether the second network node sends a paging message for MT-SDT at the second network node or sends a paging message to the UE to start MT-SDT.

[0016] In some embodiments, the one or more SDT configurations include at least one of one or more data radio bearers (DRBs), one or more service types associated with the one or more DRBs, one or more quality of service (QoS) parameters, one or more signaling radio bearers (SRBs), or one or more thresholds associated with the SDT.

[0017] In some embodiments, the method further comprises transmitting, to the second network node, second information indicating whether the first network node decides to start MT-SDT for the UE.

[0018] In some embodiments, the second information is included in a message for requesting the UE context from the second network node via an interface between the first network node and the second network node, or the second information is included in a message other than a message for requesting the UE context from the second network node via an interface between the first network node and the second network node.

[0019] In some implementations, the method further includes determining to start MT-SDT for the UE for a duration.

[0020] Yet another embodiment of the present disclosure provides a first network node, the first network node including a processor and a transceiver coupled to the processor, wherein the processor is configured to provide first information related to a Mobile Terminated Small Data Transmission (MT-SDT) to a user equipment (UE), and, when the UE is in a non-RRC_CONNECTED state, for example, the UE is in an RRC_INACTIVE state or an RRC_IDLE state, to send the first information related to the MT-SDT to the UE via the transceiver to a second network node, such that the second node determines whether to indicate the MT-SDT to the UE.

[0021] In some embodiments, the first information is included in a RAN paging message to the second network node, or the first information is included in another message other than a RAN paging message to the second network node.

[0022] In some embodiments, the first information related to the Mobile Terminated Small Data Transmission MT-SDT includes at least one of the following: a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations; a third information element indicating a second network node that decides whether to start MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start MT-SDT for the UE; or a fifth information element indicating whether the first network node sends a paging message for MT-SDT at the first network node or sends a paging message to the UE to start MT-SDT.

[0023] In some embodiments, the one or more SDT configurations include at least one of one or more data radio bearers (DRBs), one or more service types associated with the one or more DRBs, one or more quality of service (QoS) parameters, one or more signaling radio bearers (SRBs), or one or more thresholds associated with the SDT.

[0024] In some embodiments, the transceiver is further configured to receive second information from the second network node indicating whether the second network node decides to start MT-SDT for the UE.

[0025] In some embodiments, the second information is included in a message for requesting the UE context from the second network node via an interface between the first network node and the second network node, or the second information is included in a message other than a message for requesting the UE context from the second network node via an interface between the first network node and the second network node.

[0026] In some implementations, the processor is further configured to determine to start MT-SDT for the UE for a duration.

[0027] Yet another embodiment of the present disclosure provides a method, implemented by a first network node, comprising: providing first information related to a Mobile Terminated Small Data Transmission (MT-SDT) for a user equipment (UE); and, if the UE is in a non-RRC_CONNECTED state, sending the first information related to the MT-SDT for the UE to a second network node, such that the second node determines whether to indicate the MT-SDT to the UE.

[0028] In some embodiments, the first information is included in a RAN paging message to the second network node, or the first information is included in another message other than a RAN paging message to the second network node.

[0029] In some embodiments, the first information includes at least one of the following: a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations; a third information element indicating a second network node that decides whether to start MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start MT-SDT for the UE; or a fifth information element indicating whether the first network node sends a paging message for MT-SDT at the first network node or sends a paging message to the UE to start MT-SDT.

[0030] In some embodiments, the one or more SDT configurations include at least one of one or more data radio bearers (DRBs), one or more service types associated with the one or more DRBs, one or more quality of service (QoS) parameters, one or more signaling radio bearers (SRBs), or one or more thresholds associated with the SDT.

[0031] In some embodiments, the method further comprises receiving second information from the second network node indicating whether the second network node decides to start MT-SDT for the UE.

[0032] In some embodiments, the second information is included in a message for requesting the UE context from the second network node via an interface between the first network node and the second network node, or the second information is included in a message other than a message for requesting the UE context from the second network node via an interface between the first network node and the second network node.

[0033] In some implementations, the method further includes determining to start MT-SDT for the UE for a duration. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a schematic diagram of a wireless communication system according to some embodiments of the present disclosure. [Figure 2] FIG. 1 illustrates an example Mobile Terminating Early Data Transmission (MT-EDT) for user plane Cellular Internet of Things (CIoT) Enhanced Packet System (EPS) optimization according to some embodiments of the present disclosure. [Figure 3] FIG. 1 illustrates an example scenario of RAN paging in accordance with some embodiments of the present disclosure. [Figure 4] FIG. 1 illustrates an example method implemented by a first network node for wireless communication according to some embodiments of the present disclosure. [Figure 5] FIG. 10 illustrates an example method implemented by another network node for wireless communication according to some embodiments of the present disclosure. [Figure 6] FIG. 1 is an exemplary block diagram of an apparatus according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0035] The detailed description of the accompanying drawings is intended to illustrate presently preferred embodiments of the invention and is not intended to represent the only form in which the invention may be practiced. It is understood that the same or equivalent function may be performed by different embodiments that are intended to be included within the spirit and scope of the invention.

[0036] Although operations are shown in the figures in a particular order, those skilled in the art will readily understand that such operations need not be performed in the particular order shown, or in sequential order, or that not all illustrated operations need be performed, and in some cases one or more operations may be omitted, to achieve desirable results. Additionally, the figures may generally depict one or more exemplary processes in flow diagram form. However, other operations not shown may be incorporated into the generally depicted exemplary process. For example, one or more additional operations may be performed before, after, concurrently with, or between any of the illustrated operations. In some environments, multitasking and parallel processing may be advantageous.

[0037] FIG. 1 illustrates a schematic diagram of a wireless communication system according to some embodiments of the present disclosure.

[0038] As shown in Figure 1, the wireless communication system includes a UE 101, a base station (BS) 102-A, a base station 102-B, and a base station 102-C. Although a particular number of UEs and BSs are shown in Figure 1, those skilled in the art will recognize that any number of UEs and BSs may be included in the wireless communication system.

[0039] The UE 101 may include a computing device such as a desktop computer, a laptop computer, a personal digital assistant (PDA), a tablet computer, a smart television (e.g., a television connected to the Internet), a set-top box, a game console, a security system (including security cameras), a vehicle-mounted computer, a network device (e.g., a router, a switch, a modem), etc. According to one embodiment of the present disclosure, the UE 101 may include a portable wireless communication device, a smartphone, a mobile phone, a flip phone, a device with a subscriber identity module, a personal computer, a selective call receiver, or any other device capable of transmitting and receiving communication signals over a wireless network. In some embodiments, the UE 101 includes a wearable device such as a smart watch, a fitness band, an optical head-mounted display, etc. Furthermore, the UE 101 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, the UE 101, a user terminal, a device, or other terms used in the art. The UE 101 may communicate directly with a BS via uplink (UL) communication signals.

[0040] The BSs may be distributed throughout a geographic region. In some embodiments, the BSs may be referred to as access points, access terminals, bases, base stations, macrocells, Node Bs, enhanced Node Bs (eNBs), 5G base stations using NR technology, gNBs, gNode Bs, Home Node Bs, relay nodes, devices, or any other terminology used in the art. The BSs are generally part of a radio access network, which may include one or more controllers communicatively coupled to one or more corresponding BSs.

[0041] A wireless communication system may conform to any type of network capable of transmitting and receiving wireless communication signals. For example, a wireless communication system may conform to a wireless communications network, a cellular network, a time division multiple access (TDMA)-based network, a code division multiple access (CDMA)-based network, an orthogonal frequency division multiple access (OFDMA)-based network, an LTE network, a 3rd Generation Partnership Project (3GPP®)-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and / or other communications network.

[0042] In one implementation, the wireless communication system is compliant with the 3GPP protocol NR, where the BS transmits using an Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme in the DL and the UE 101 transmits using a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme or an OFDM scheme in the uplink. However, more generally, the wireless communication system may implement some other open or proprietary communication protocol, for example, WiMAX, among other protocols.

[0043] In other embodiments, the BS may communicate using other communication protocols, such as the IEEE 802.11 family of wireless communication protocols. Additionally, in some embodiments, the BS may communicate over licensed spectrum, while in other embodiments, the BS may communicate over unlicensed spectrum. This disclosure is not intended to be limited to a particular wireless communication system architecture or protocol implementation. In another embodiment, the BS may communicate with the UE 101 using 3GPP 5G protocols.

[0044] As shown in Figure 1, assume that there are three cells in the UE's RNA, the three cells being cell A, cell B, and cell C. Cell A is controlled by BS 102-A, cell B is controlled by BS 102-B, and cell C is controlled by BS 102-C. UE 101 was served by BS 102-A and was in RRC_INACTIVE or RRC_IDLE state. UE 101 then left the cell controlled by BS 102-A and is now camped on cell B controlled by BS 102-B.

[0045] FIG. 2 illustrates an example Mobile-Terminated Early Data Transmission (MT-EDT) for user-plane Cellular Internet of Things (CIoT) Enhanced Packet System (EPS) optimization according to some embodiments of the present disclosure.

[0046] In FIG. 2, there are four components, including a UE, a BS, a mobility management entity (MME), and a serving gateway (S-GW).

[0047] In operation 201, when downlink data arrives for the UE, the SGW may send the DL data size to the MME for MT-EDT consideration by the MME.

[0048] In operation 202, the MME includes the DL data size in an S1 Application Protocol (AP) paging message to assist the BS in triggering the MT-EDT.

[0049] In operation 203, if the data can fit into one single downlink transmission according to the UE category included in the UE Radio Capability for Paging provided in the S1-AP paging message, the BS includes an MT-EDT indication in the paging message to the UE.

[0050] In operation 204, the UE initiates the MO-EDT procedure for user plane CIoT EPS optimization.

[0051] In particular, the following actions may be taken: 1) The UE selects a random access preamble that is not configured for EDT. 2) The UE sends an RRCConnectionResumeRequest message with resume cause MT-EDT and no user data. 3) The BS initiates the S1-AP Context Resume procedure to resume the S1 connection and reactivate the SI-U bearer. 4) The MME asks the S-GW to reactivate the S1-U bearer for the UE. 5) The MME may include a Pending Data Indication in the S1AP UE Context Resume Response message to inform the BS of further data traffic beyond what was originally signaled in step 2. The BS may use this indication to decide whether to release the UE. 6) The uplink data is delivered to the S-GW. 7) If downlink data is available, the S-GW sends the downlink data to the BS. 8) If no further data is expected, the BS may initiate suspension of the S1 connection and reactivation of the S1-U bearer. 9) The BS sends an RRCConnectionRelease message to keep the UE in RRC_IDLE. The message contains releaseCause set to rrc-Suspend, resumeID, NextHopChainingCount, and drb-ContinueROHC, which are stored by the UE. If downlink data was received in step 6, it is sent encrypted on the DTCH multiplexed with the RRCConnectionRelease message on the DCCH.

[0052] FIG. 3 illustrates an example scenario of RAN paging according to some embodiments of the present disclosure.

[0053] 3 includes two network nodes, which are network node 1 and network node 2. The network node may be an NG-RAN node, an eNB, a gNB, a BS, etc.

[0054] The purpose of the RAN paging procedure is to allow network node 1 to request paging of a UE at network node 2, and the procedure uses non-UE related signaling.

[0055] The RAN paging procedure is triggered by network node 1 by sending a RAN paging message to network node 2, in which necessary information such as the UE RAN Paging Identity is provided.

[0056] If the RAN paging message includes a Paging Priority IE, the network node 2 may use it to prioritize the paging.

[0057] If the RAN paging message includes an Assistance Data for RAN Paging IE, the NG-RAN node 2 may use it.

[0058] If the RAN paging message includes a UE Radio Capability for Paging IE, the network node 2 may use it to apply a particular paging scheme.

[0059] In MT-SDT, which stands for Mobile Terminated Small Data Transmission, it refers to a DL triggered SDT due to a paging message that does not transition to RRC_CONNECTED, in other words, a small data transmission from the BS to the UE that does not transition the UE to the RRC_CONNECTED state.

[0060] Currently, RAN paging messages are used to allow one NG-RAN node to request paging of a UE at another NG-RAN node. For example, RAN paging may be performed using Xn RAN paging between nodes managing cells within a RAN-based notification area (RNA) configured for the UE. For example, cell A and cell B are within the UE's RNA, and Xn RAN paging may be performed between node A (managing cell A) and node B (managing cell B).

[0061] According to this specification, when a UE is in the RRC_INACTIVE state, the UE may move within its RNA without notifying the NG-RAN. In other words, the UE may be in the RRC_INACTIVE state, and the UE leaves its previous serving gNB and camps on a cell controlled by another gNB in ​​the RNA. Under this scenario, when DL small data arrives at the previous serving gNB, the existing Xn RAN paging procedure cannot identify MT-SDT and therefore cannot support MT-SDT. To solve this problem, the present disclosure proposes several solutions for paging enhancement in MT-SDT.

[0062] Embodiment 1: In this embodiment, the first gNB in ​​the UE's RNA, rather than the UE's immediately preceding serving gNB, determines whether to initiate MT-SDT for the UE or a legacy or regular MT call for the UE. For example, in FIG. 1, BS 102-B may determine whether to initiate MT-SDT for UE 101 or a legacy or regular MT call for UE 101.

[0063] The UE's immediately preceding serving gNB, i.e., BS 102-A in FIG. 1, may send a RAN paging message to BS 102-B and / or BS 102-C to request paging of UE 101. The following information may be included in the RAN paging message, included in another message, or sent in a new message:

[0064] The message may include at least one of the following information: 1) Information Elements (IEs) relating to the information of the data, which may include at least one of the following: i. Download data size or volume, ii. DL data will be transmitted in one shot, i.e., one shot transmission, or iii. DL data will be transmitted in multiple shots, i.e. multiple shot transmission. 2) One or more SDT configuration related information elements, which may include at least one of the following: i. one or more Data Radio Bearers (DRBs); ii. one or more Service Types associated with one or more DRBs; iii. one or more Quality of Service (QoS) parameters; iv. one or more Signaling Radio Bearers (SRBs); or v. One or more thresholds associated with the SDT, e.g., thresholds associated with the SDT and / or threshold values ​​of the SDT. 3) An information element indicating whether the previous serving gNB sends an MT-SDT paging message at the previous serving gNB or at the previous serving cell.

[0065] After the first gNB determines whether to initiate an MT-SDT call or a legacy or normal MT call for the UE, the first gNB may send assistance information to the immediately preceding serving gNB to indicate the decision via an interface between the first gNB and the immediately preceding serving gNB, such as an Xn interface or an X2 interface. The assistance information may be referred to as an "MT-SDT or not paging," etc.

[0066] In some scenarios, the assistant information may be included in a message for retrieving a UE context, for example, a message called a RETRIEVE UE CONTEXT REQUEST message. The assistant information may be included in the message as a new or additional information element, or may reuse an existing information element in the message.

[0067] In some other scenarios, instead of being included in another message, the assistant information may be sent in a new message from the first gNB to the immediately preceding serving gNB via the interface between the first gNB and the immediately preceding serving gNB.

[0068] In yet another scenario, if the first gNB does not send assistance information to the immediately preceding serving gNB, it means that the first gNB does not initiate MT-SDT for the UE, i.e., the first gNB may initiate a legacy or normal MT call, or if the first gNB does not send assistance information to the immediately preceding serving gNB, it means that the first gNB initiates MT-SDT for the UE.

[0069] It should be noted that in some cases, the immediately preceding serving gNB may send an MT-SDT RAN paging message at the immediately preceding serving gNB, and the first gNB may take into account the MT-SDT RAN paging message sent by the immediately preceding serving gNB, and other factors may be taken into account as well, such as the UE capabilities of the UE, the first gNB's own capabilities, latency requirements, etc. If the criteria for initiating MT-SDT are met, the first gNB may send an MT-SDT paging message to the UE. In some other scenarios, if some criteria for initiating MT-SDT cannot be met, the first gNB may initiate a normal MT call to the UE.

[0070] Embodiment 2 In this embodiment, a first gNB, which may be the UE's immediately preceding serving gNB, determines which network node (which may be referred to as the second gNB) is responsible for determining the paging type. In other words, the immediately preceding serving gNB may indicate to the second gNB in ​​the UE's RNA whether to initiate MT-SDT for the UE or a legacy or normal MT call for the UE. For example, in FIG. 1, BS 102-A, the UE's immediately preceding serving gNB, may determine that it is BS 102-B that determines whether to initiate MT-SDT for the UE 101 or a legacy or normal MT call for the UE's MT.

[0071] The UE's immediately preceding serving gNB, i.e., BS102-A in FIG. 1, may send a RAN paging message to BS102-B and / or BS102-C to request paging of UE 101. The following information may be included in the RAN request message, in another message, or sent in a new message: 1) An information element that indicates which network node determines the paging type. For example, if the value of the IE is "1", "y", "Y", or "yes", it means that the network node receiving the message decides the paging type, i.e., whether to initiate MT-SDT for the UE or legacy or normal MT for the UE. If the value of the IE is "0", "n", "N", or "no", it means that the network node receiving the message does not determine the paging type. In this case, the paging type may be determined by the immediately previous serving gNB or another gNB. In some other cases, a value of '1' in the IE means that the immediately preceding serving node determines the paging type, and a value of '0' in the IE means that another network node determines the paging type. It should be noted that the meaning of the values ​​of the IEs may be defined in other ways, and this disclosure does not intend to limit the meaning of the values ​​of the IEs. 2) Information elements related to the information of the data, which may include at least one of the following: i. Download data size or volume, ii. The data is to be transmitted in one shot, i.e., it is a one-shot transmission, or iii. Data will be transmitted in multiple shots, i.e., multiple shot transmission. The value of the IE may also indicate which network node determines the information of the data. For example, a value of '0' in the IE means that the immediately preceding serving gNB determines the information of the data, and a value of '1' in the IE means that the second gNB receiving this message (including the IE) will determine the information of the data. In this embodiment, the information element relating to the data information may or may not be transmitted from the immediately preceding serving gNB. 3) One or more SDT configuration related information elements, which may include at least one of the following: i. one or more DRBs; ii. one or more Service Types associated with one or more DRBs; iii. one or more QoS parameters; iv. one or more SRBs; or v. One or more thresholds associated with the SDT, e.g., thresholds associated with the SDT and / or threshold values ​​of the SDT. The value of the IE may also indicate which network node determines one or more SDT configurations. For example, a value of '0' in the IE means that the immediately preceding serving gNB determines the SDT configuration, and a value of '1' in the IE means that the second gNB receiving this message (including the IE) determines the SDT configuration. In this embodiment, information elements related to the SDT configuration may or may not be transmitted from the immediately preceding serving gNB. 4) An information element indicating whether the immediately preceding serving gNB sends a paging message for MT-SDT. For example, an IE value of "0" indicates that the immediately preceding serving gNB does not send MT-SDT paging messages, and an IE value of "1" indicates that the immediately preceding serving gNB sends MT-SDT paging messages, and vice versa. Alternatively, a value of "0" in the IE indicates that the immediately preceding serving gNB sends a paging message for a normal MT call, and a value of "1" in the IE indicates that the immediately preceding serving gNB sends a paging message for an MT-SDT call, and vice versa.

[0072] If the immediately preceding serving gNB indicates a second gNB (e.g., BS 102-B in FIG. 1) to determine the paging type, BS 102-B may send assistance information to indicate the paging type determination. The assistance information may be referred to as "MT-SDT or not paging," "MT-SDT or normal MT call paging," "paging type," etc.

[0073] If the immediately preceding serving gNB indicates to other gNBs that it is the immediately preceding serving gNB itself that determines the paging type, the other gNBs do not need to send assistance information to the immediately preceding serving gNB.

[0074] In some scenarios, the assistant information may be included in a message for retrieving a UE context, for example, a message called a RETRIEVE UE CONTEXT REQUEST message. The assistant information may be included in the message as a new or additional information element, or may reuse an existing information element in the message.

[0075] In some other scenarios, instead of being included in another message, the assistance information may be sent in a new message from the second gNB to the immediately preceding serving gNB via the interface between the second gNB and the immediately preceding serving gNB.

[0076] In some cases, the serving gNB immediately prior to receiving the assistance information may transfer only part of the UE context, for example, the context related to the SDT DRB.

[0077] Embodiment 3 In this embodiment, the first gNB, which may be the immediately preceding serving gNB of the UE, decides whether to initiate MT-SDT for the UE or a legacy or regular MT call for the UE. For example, in FIG. 1, BS 102-A, the immediately preceding serving gNB of the UE, decides whether to initiate MT-SDT for the UE 101 or a legacy or regular MT call for the UE 101.

[0078] The immediately preceding serving gNB may send a message containing at least one of the following information elements to other gNBs within the UE's RNA: 1) An information element that indicates whether another BS initiates MT-SDT to the UE by sending an MT-SDT paging message. For example, a value of "1" in the IE indicates that other BSs should initiate MT-SDT for the UE, and a value of "0" in the IE indicates that other BSs should not initiate MT-SDT for the UE, or vice versa. Considering the scenario of Figure 1, the immediately preceding serving gNB, i.e., BS 102-A in Figure 1, indicates to BS 102-B to initiate MT-SDT for UE 101. BS 102-B should take this indication into account to determine whether to initiate MT-SDT for UE 101. If the requirements for initiating MT-SDT are met, BS 102-B sends an MT-SDT paging message to UE 101. In some other scenarios, if some requirements for initiating MT-SDT cannot be met, BS 102-B may initiate a normal MT call for UE 101. 2) An information element indicating whether the immediately preceding serving gNB sends a paging message for MT-SDT. For example, an IE value of "0" indicates that the immediately preceding serving gNB does not send MT-SDT paging messages, and an IE value of "1" indicates that the immediately preceding serving gNB sends MT-SDT paging messages, and vice versa. Alternatively, a value of "0" in the IE indicates that the immediately preceding serving gNB sends a paging message for a normal MT call, and a value of "1" in the IE indicates that the immediately preceding serving gNB sends a paging message for an MT-SDT call, and vice versa.

[0079] Embodiment 4 In this embodiment, the immediately preceding serving gNB and / or other gNBs (or cells) in the UE's RNA apply the same paging type strategy. That is, all gNBs (or cells) in the UE's RNA send paging messages for MT-SDT, and the decision may apply to one MT-SDT, or all MT-SDTs, or for a certain duration. Alternatively, all gNBs (or cells) in the UE's RNA send paging messages for normal MT calls, and the decision may apply to one MT-SDT, or all MT-SDTs, or for a certain duration. The paging type strategy may be specified, predefined, or instructed by the control node.

[0080] The immediately preceding serving gNB of the UE decides whether to initiate MT-SDT or a legacy or regular MT call for the UE. For example, in Figure 1, BS 102-A, the immediately preceding serving gNB of the UE, decides whether to initiate MT-SDT or a legacy or regular MT call for the UE 101.

[0081] In this embodiment, the immediately preceding serving gNB may send a message containing the same information as described in embodiment 3.

[0082] FIG. 4 illustrates an example method implemented by a first network node for wireless communication according to some embodiments of the present disclosure.

[0083] In operation 401, a first network node receives first information related to MT-SDT for a UE from a second network node, and in operation 402, the network node determines whether to indicate MT-SDT to the UE based on at least the first information received from the second network node. For example, taking FIG. 1 as an example, UE 101 is in an RRC_IDLE state or an RRC_INACTIVE state, and the RNA of the UE includes cell A, cell B, and cell C. BS 102-B may receive first information related to MT-SDT for UE 101 from BS 102-A, and BS 102-B determines whether to start MT-SDT for UE 101 based on at least the first information received from BS 102-A.

[0084] The first information may be included in a RAN paging message from the second network node, or the first information is included in another message other than a RAN paging message from the second network node.

[0085] The first information related to the MT-SDT of the UE includes at least one of the following: 1) A first information element indicating the size of downlink data for the UE. 2) One or more second information elements indicating one or more SDT configurations. 3) A third information element indicating the first network node that decides whether to initiate MT-SDT for the UE. 4) A fourth information element indicating a network node that decides whether to start MT-SDT for the UE. Note that the network node may include any network node in the RNA of the UE, including the immediately preceding serving node. For example, the immediately preceding serving node may send the first information to another node in the RNA of the UE to indicate that the immediately preceding serving node will decide whether to start MT-SDT for the UE. Or 5) A fifth information element indicating whether the second network node sends a paging message for MT-SDT at the second network node or sends a paging message to the UE to start MT-SDT.

[0086] In some embodiments, the one or more SDT configurations may include at least one of one or more DRBs, one or more service types associated with one or more DRBs, one or more service QoS parameters, one or more SRBs, or one or more thresholds associated with the SDT.

[0087] In some cases, the first network node may transmit second information to the second network node indicating whether the first network node decides to start MT-SDT for the UE. For example, after determining whether to start MT-SDT for the UE 101, BS 102-B may transmit a decision of whether to start MT-SDT to BS 102-A.

[0088] In some embodiments, the second information is included in a message for requesting the UE context from the second network node via an interface between the first network node and the second network node, or the second information is included in a message other than a message for requesting the UE context from the second network node via an interface between the first network node and the second network node. For example, the second information may be included in a message such as a "RETRIEVE UE CONTEXT REQUEST" message or other message via an Xn interface or an X2 interface between gNBs.

[0089] In some implementations, the first network node decides to start MT-SDT for the UE for a certain duration, i.e., within that duration, the first network node always starts MT-SDT for the UE.

[0090] FIG. 5 illustrates an example method performed by another network node for wireless communication according to some embodiments of the present disclosure.

[0091] In operation 501, the network node provides first information related to the MT-SDT for the UE, and in operation 502, if the UE is in a non-RRC_CONNECTED state, the network node sends the first information related to the MT-SDT for the UE to a second network node via the transceiver so that the second node determines whether to indicate the MT-SDT to the UE.

[0092] Taking FIG. 1 as an example, UE 101 is in a non-RRC_CONNECTED state, such as an RRC_IDLE state or an RRC_INACTIVE state, and the UE's RNA includes cell A, cell B, and cell C. BS 102-A may provide first information related to the MT-SDT for the UE and send the first information to BS 102-B. Here, the term "provide" suggests that BS 102-A may provide the necessary information, include it in the first information, and further transmit the first information to BS 102-B.

[0093] FIG. 6 illustrates an example block diagram of an apparatus according to some embodiments of the present disclosure.

[0094] The apparatus may be at least part of or include a BS, gNB, eBN, or other device having similar functionality.

[0095] The apparatus may include a processor and a transceiver coupled to the processor. In some embodiments, the transceiver may include a transmitter and a receiver. The processor is configured to perform any of the methods described in this disclosure, such as the methods described with respect to FIG. 4 and FIG. 5. For example, when the apparatus is implemented as a network node instead of an immediately preceding serving node, the receiver may receive, from a second network node via the transceiver, first information related to the MT-SDT for the UE, and the processor may determine whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node.

[0096] When the apparatus is implemented as an immediately preceding serving node, the processor provides first information related to the MT-SDT for the UE, and, if the UE is in a non-RRC_CONNECTED state, sends the first information related to the MT-SDT for the UE to a second network node via the transceiver so that the second node determines whether to indicate the MT-SDT to the UE.

[0097] The methods of the present disclosure may be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on hardware electronic or logic circuitry such as a general-purpose or special-purpose computer, a programmed microprocessor or microcontroller, peripheral integrated circuit elements, integrated circuits, discrete component circuits, programmable logic devices, etc. In general, any device having a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

[0098] The methods of the present disclosure may be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on hardware electronic or logic circuitry such as a general-purpose or special-purpose computer, a programmed microprocessor or microcontroller, peripheral integrated circuit elements, integrated circuits, discrete component circuits, programmable logic devices, etc. In general, any device having a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

[0099] While the present disclosure has been described using specific embodiments thereof, it is apparent that many alternatives, modifications, and variations will be apparent to those skilled in the art. For example, various components of the present embodiment may be interchanged, added, or substituted in other embodiments. Also, not all elements shown in the figures are necessary for the operation of the disclosed embodiments. For example, one skilled in the art of the disclosed embodiments will be able to make and use the teachings of the present disclosure by simply using the elements of the independent claims. Accordingly, the embodiments of the present disclosure set forth herein are intended to be illustrative, not limiting. Various modifications may be made without departing from the spirit and scope of the present disclosure.

[0100] In this disclosure, relational terms such as “first,” “second,” and the like may be used merely to distinguish one entity or action from another and do not necessarily require or imply such an actual relationship or order between such entities or actions. The terms “comprise,” “comprising,” or other variations thereof are intended to include a non-exclusive inclusion; a process, method, article, or apparatus that includes a list of elements does not include only those elements, but may include other elements not expressly listed or inherent in such process, method, article, or apparatus. An element preceded by “a,” “an,” etc., does not, absent further constraints, preclude the presence of additional identical elements in a process, method, article, or apparatus that includes the element. Additionally, the term “another” is defined as at least a second or more. As used herein, terms such as “including,” “having,” and the like are defined as “comprising.” [Explanation of symbols]

[0101] 101 User Equipment (UE) 102 Base station (BS)

Claims

1. a first network node, a processor; a transceiver coupled to the processor; Equipped with the processor: receiving, via the transceiver, first information related to a Mobile Terminated Small Data Transmission (MT-SDT) for a User Equipment (UE) from a second network node, the first information being included in a Radio Access Network (RAN) paging message from the second network node; determining whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node; a first network node configured to:

2. The first information related to the MT-SDT of the UE, a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations, or a third information element indicating the first network node that decides whether to start the MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start the MT-SDT for the UE; a fifth information element indicating whether the second network node sends a paging message for the MT-SDT at the second network node or sends a paging message to the UE to start the MT-SDT; The first network node of claim 1, comprising at least one of:

3. the one or more SDT configurations: one or more Data Radio Bearers (DRBs), or one or more service types associated with said one or more DRBs; one or more Quality of Service (QoS) parameters, or one or more Signaling Radio Bearers (SRBs), or One or more thresholds associated with the SDT The first network node of claim 2, comprising at least one of:

4. The transceiver sending second information to the second network node indicating whether the first network node decides to start the MT-SDT for the UE; The first network node of claim 1 further configured to:

5. the second information is included in a message for requesting a UE context from the second network node via an interface between the first network node and the second network node; or the second information is included in a message other than the message for requesting a UE context from the second network node via the interface between the first network node and the second network node.

5. The first network node of claim 4.

6. the processor: determining to start the MT-SDT for the UE for a certain duration; The first network node of claim 1 further configured to:

7. receiving first information related to a Mobile Terminated Small Data Transmission (MT-SDT) for a User Equipment (UE) from a second network node, the first information being included in a Radio Access Network (RAN) paging message from the second network node; determining whether to indicate the MT-SDT to the UE based on at least the first information received from the second network node; a first network node configured to receive a first packet from the first network node;

8. a first network node, a processor; a transceiver coupled to the processor; Equipped with the processor: providing first information related to a mobile terminated small data transmission (MT-SDT) to a user equipment (UE); If the UE is in a non-RRC_CONNECTED state, sending the first information related to the MT-SDT for the UE to the second network node via the transceiver, so that the second network node determines whether to indicate the MT-SDT to the UE, wherein the first information is included in a Radio Access Network (RAN) paging message to the second network node; a first network node configured to:

9. The first information related to a mobile terminated small data transmission MT-SDT is: a first information element indicating a size of downlink data for the UE; one or more second information elements indicating one or more SDT configurations, or a third information element indicating the second network node that decides whether to start the MT-SDT for the UE; a fourth information element indicating a network node that decides whether to start the MT-SDT for the UE; a fifth information element indicating whether the first network node sends a paging message for the MT-SDT at the first network node or sends a paging message to the UE to start the MT-SDT; 9. The first network node of claim 8, comprising at least one of:

10. the one or more SDT configurations: one or more Data Radio Bearers (DRBs), or one or more service types associated with said one or more DRBs; one or more Quality of Service (QoS) parameters, or one or more Signaling Radio Bearers (SRBs), or One or more thresholds associated with the SDT 10. The first network node of claim 9, comprising at least one of:

11. The transceiver receiving second information from the second network node indicating whether the second network node decides to start the MT-SDT for the UE; The first network node of claim 8, further configured to:

12. the second information is included in a message for requesting a UE context from the second network node via an interface between the first network node and the second network node; or the second information is included in a message other than the message for requesting a UE context from the second network node via the interface between the first network node and the second network node.

12. The first network node of claim 11.

13. the processor: determining to start the MT-SDT for the UE for a certain duration; The first network node of claim 8, further configured to:

14. A computer program for causing a computer to function as a processor of a first network node described in any one of claims 1 to 6.

15. A computer program for causing a computer to function as a processor of a first network node according to any one of claims 8 to 13.

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