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EP-4513984-B1 - METHODS FOR SMALL DATA TRANSMISSION IN AN INACTIVE STATE OF A USER EQUIPMENT

EP4513984B1EP 4513984 B1EP4513984 B1EP 4513984B1EP-4513984-B1

Inventors

  • ZHANG, JIAN

Dates

Publication Date
20260506
Application Date
20230421

Claims (14)

  1. A data transmission method, applied to a network device, wherein the method comprises: a) receiving (S301) a first downlink data packet; b) if the first downlink data packet meets a preset transmission scenario, sending (S302) an enhanced paging message to a user equipment, wherein c) the enhanced paging message carries a mobile-terminated small data transmission indication, wherein the mobile-terminated small data transmission indication is used to indicate the user equipment, when the user equipment is in a radio resource control, RRC, inactive state, to activate a corresponding target bearer; and d) receiving (S304) a paging response message sent by the user equipment, and sending (S305) the first downlink data packet to the user equipment on the activated target bearer when the user equipment is in the RRC inactive state; and e) wherein the preset transmission scenario comprises any one of the following conditions: the downlink data packet is a small data packet, the downlink data packet is in a preset mobile-terminated small data transmission list in the network device, or the downlink data packet carries corresponding indication information and the indication information is used to indicate whether mobile-terminated small data transmission is triggered for the downlink data packet.
  2. The data transmission method according to claim 1, wherein the enhanced paging message further carries a trigger indication and a receive indication, the trigger indication is used to indicate the user equipment not to send an RRC resume request message to the network device when receiving the enhanced paging message, and the receive indication is used to indicate the user equipment to receive, in the RRC inactive state, the first downlink data packet sent by the network device.
  3. The data transmission method according to claim 1 or 2, wherein the network device sends the first downlink data packet to the user equipment by using a downlink media access control layer protocol data unit, wherein the downlink media access control layer protocol data unit carries a media access control layer control unit, and the media access control layer control unit is configured to indicate the user equipment, after receiving the enhanced paging message and when the user equipment is in the RRC inactive state, not to send the RRC resume request message to the network device, and to directly receive, in the RRC inactive state, the first downlink data packet sent by the network device.
  4. The data transmission method according to any one of claims 1 to 3, wherein the enhanced paging message further carries a bearer identity, so that the user equipment activates the corresponding target bearer based on the bearer identity and the mobile-terminated small data transmission indication.
  5. The data transmission method according to any one of claims 1 to 4, wherein the method further comprises: receiving a second downlink data packet to be sent to the user equipment, and if the second downlink data packet does not meet the preset transmission scenario, or/and receiving an uplink data packet sent by the user equipment, and if the uplink data packet does not meet the preset transmission scenario, sending an RRC resume message to the user equipment, so that the user equipment migrates from the RRC inactive state to an RRC connected state, wherein time for receiving the first downlink data packet by the network device is earlier than time for receiving the second downlink data packet and the uplink data packet by the network device.
  6. The data transmission method according to claim 5, wherein a method for determining that the second downlink data packet does not meet the preset transmission scenario, and/or that the uplink data packet does not meet the preset transmission scenario comprises/comprise: the second downlink data packet is a non-small data packet, or/and the uplink data packet is a non-small data packet, or/and a quantity of the second downlink data packets is greater than a quantity threshold, or/and a quantity of the uplink data packets is greater than a quantity threshold, or/and a size of the second downlink data packet is greater than a size threshold, or/and a size of the uplink data packet is greater than a size threshold.
  7. The data transmission method according to any one of claims 1 to 6, wherein when sending the first downlink data packet to the user equipment, the method further comprises: determining that the first downlink data packet is a single data packet; or starting, by the network device, a small data timer when sending the first downlink data packet to the user equipment, and if the small data timer expires and no new downlink data packet to be sent to the user equipment is received, sending an RRC release message to the user equipment.
  8. A data transmission method, applied to a user equipment, wherein the method comprises: a) receiving (S302) an enhanced paging message sent by a network device, wherein the enhanced paging message carries a mobile-terminated small data transmission indication, wherein the mobile-terminated small data transmission indication is used to indicate the user equipment, when the user equipment is in a radio resource control, RRC, inactive state, to activate a corresponding target bearer; b) activating (S303) a corresponding target bearer based on the mobile-terminated small data transmission indication, and the user equipment is in an RRC inactive state; c) sending (S304) a paging response message to the network device; and d) receiving (S305), based on the target bearer, a first downlink data packet sent by the network device when the user equipment is in the RRC inactive state.
  9. The data transmission method according to claim 8, wherein the enhanced paging message further carries a trigger indication and a receive indication, the trigger indication is used to indicate the user equipment not to send an RRC resume request message to the network device when receiving the enhanced paging message, and the receive indication is used to indicate the user equipment to receive, in the RRC inactive state, the first downlink data packet sent by the network device.
  10. The data transmission method according to claim 8 or 9, wherein the network device sends the first downlink data packet to the user equipment by using a downlink media access control layer protocol data unit, wherein the downlink media access control layer protocol data unit further carries a media access control layer control unit, and the media access control layer control unit is configured to indicate the user equipment, after receiving the enhanced paging message and when the user equipment is in the RRC inactive state, not to send the RRC resume request message to the network device, and to directly receive, in the RRC inactive state, the first downlink data packet sent by the network device.
  11. The data transmission method according to any one of claims 8 to 10, wherein the RRC inactive state comprises a first RRC inactive state and a second RRC inactive state, and when sending the paging response message to the network device, the user equipment is in the first RRC inactive state, and the method further comprises: starting a small data packet timer; and if the small data packet timer expires, deactivating the target bearer and migrating the user equipment from the first RRC inactive state to the second RRC inactive state.
  12. The data transmission method according to any one of claims 8 to 11, wherein the method further comprises: receiving a second downlink data packet; and if the second downlink data packet does not meet a preset receiving scenario, or/and sending an uplink data packet to the network device, and if the uplink data packet does not meet the preset receiving scenario, sending the RRC resume request message to the network device, so that the user equipment migrates from the RRC inactive state to an RRC connected state, wherein time for receiving the first downlink data packet by the user equipment is earlier than time for receiving the second downlink data packet and sending the uplink data packet by the user equipment.
  13. The data transmission method according to claim 12, wherein that the second downlink data packet does not meet the preset receiving scenario, or/and the uplink data packet do not meet the preset receiving scenario comprises: the second downlink data packet is a non-small data packet, or/and the uplink data packet is a non-small data packet, or/and a quantity of the second downlink data packets is greater than a quantity threshold, or/and a quantity of the uplink data packets is greater than a quantity threshold, or/and a size of the second downlink data packet is greater than a size threshold, or/and a size of the uplink data packet is greater than a size threshold.
  14. The data transmission method according to any one of claims 8 to 13, wherein the enhanced paging message further carries a bearer identity, so that the user equipment activates the corresponding target bearer based on the bearer identity and the mobile-terminated small data transmission indication.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS Priority is claimed to Chinese Patent No. 202210573972.4, filed with the China National Intellectual Property Administration on May 24, 2022 and entitled "DATA TRANSMISSION METHOD AND RELATED DEVICE". TECHNICAL FIELD This disclosure generally relates to the field of communication technologies, and the invention specifically, relates to methods for small data transmission. BACKGROUND In a 5th-generation (5G) new radio (NR) network, to improve efficiency of frequent transmission of a small data packet, a radio resource control (RRC) state is introduced: an RRC inactive (Inactive) state. When user equipment (UE) is in the RRC inactive state, if a gNB sends a downlink data packet or signaling to the user equipment, the user equipment needs to migrate from the RRC inactive state to an RRC connected state to receive the downlink data packet or signaling. In addition, after the user equipment successfully receives the data sent by the gNB, the user equipment subsequently switches from the RRC connected state to the RRC inactive state. Because the gNB sends the downlink data packet or signaling to the user equipment relatively frequently, the user equipment needs to frequently migrate between the RRC inactive state and the RRC connected state, and consequently, signaling overheads are relatively high, which increases power consumption of the user equipment. Moreover, if the user equipment remains in the RRC connected state after the user equipment successfully receives the data sent by the gNB, if a service frequency is not high, for example, a period in which the gNB sends the downlink data packet to the user equipment is very long, the user remains in the RRC connected state for a long time, resulting in excessively large power consumption of the user equipment. WO 2022/087275 A1 discloses a small data transmission (SDT) procedure that considers transmission of a RRC resume request message (for the SDT procedure), by the UE, to the base station as a response to the paging message. WO 2021/228197 A1 discloses a method which considers reception of a dedicated control signaling related to one NUL and SUL frequency carrier and performing only uplink data transmission by the UE which is in a RRC_INACTIVE state. SUMMARY The object of the invention is to provide a data transmission method, to resolve a problem that signaling overheads of user equipment are relatively high due to frequent transmission of a small data packet. This object is solved by the attached independent claims and further embodiments and improvements of the invention are listed in the attached dependent claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flowchart of a data transmission method;FIG. 2 is a flowchart of another data transmission method;FIG. 3 is a flowchart of a data transmission method according to an implementation of this application;FIG. 4 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 5 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 6 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 7 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 8 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 9 is a schematic flowchart of an information exchange scenario in a data transmission method according to another implementation of this application;FIG. 10 is a schematic diagram of a structure of a network device according to an implementation of this application; andFIG. 11 is a schematic diagram of a structure of user equipment according to an implementation of this application. The implementation depicted in figure 3 and the corresponding description are according to the claimed invention. The embodiments/examples/implementations depicted in figures 1-2 and 4-11 and their description are not or not completely covered by the claimed invention and are for illustration purposes only. DESCRIPTION OF EMBODIMENTS It should be noted that in the embodiments of this application, "at least one" means one or more, and "a plurality of" means two or more. "And/or" describes an association relationship between associated objects, and indicates that three relationships may exist. For example, "A and/or B" may indicate the following cases: only A exists, both A and B exist, and only B exists, where A and B may be singular or plural. The terms "first", "second", "third", "fourth" and the like (if they exist) in the specification, claims, and accompanying drawings of this application are used to distinguish between sim