IP Library › Granted Patent US 12684626

Granted Patent B2

US 12684626 · App. 18/251,083 · Granted Jul 14, 2026

Method and apparatus for small data transmission

Inventors: Ran Yue (Beijing, CN); Haiming Wang (Beijing, CN); Jie Shi (Beijing, CN); Lianhai Wu (Beijing, CN); Min Xu (Beijing, CN)

Assignee: Lenovo (Beijing) Limited

H04W74/0875

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Quick Facts

Patent No.: US 12684626
App. No.: 18/251,083
Granted: Jul 14, 2026
Kind: B2

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Abstract

Embodiments of the present application are directed to a method and apparatus for small data transmission. In an embodiment of the present application, the method includes: selecting a channel access priority class (CAPC) for small data transmission (SDT) based on a rule if the CAPC for SDT is not indicated by a base station; and performing SDT based on the CAPC for the SDT.

Claims (101)

1 . A method, performed by a user equipment (UE), comprising:

selecting a channel access priority class (CAPC) to be used for small data transmission (SDT) based on a rule if a CAPC for SDT is not indicated by a base station;

performing SDT based on the CAPC for SDT; and

wherein the selecting of CAPC for the SDT and the performing of the SDT are based on the selected CAPC for uplink (UL) SDT during at least configured grant (CG) based SDT, and wherein selecting the CAPC to be used for SDT based on a rule comprises selecting a highest or lowest priority CAPC of at least one common control channel (CCCH) if the CCCH or at least one dedicated control channel (DCCH) service data unit (SDU) or MAC CE is included for SDT.

2 . The method of claim 1 , further comprising: (i) receiving information of the CAPC for SDT by a system broadcast message or radio resource control (RRC) signaling, or (ii) predefining the CAPC for SDT.

3 . The method of claim 2 , wherein the information of the CAPC for SDT is used for one or more of:

at least one of signaling radio bearer (SRB)0, SRB1, and SRB3;

assistant information for SDT and at least one of SRB0, SRB1, and SRB3;

logical channel including assistant information for SDT;

an entire SDT message;

data part of SDT or each dedicated traffic channel (DTCH) logical channel;

each logical channel;

medium access control (MAC) control element (CE); or

data radio bearer (DRB).

4 . The method of claim 1 , wherein selecting the CAPC to be used for SDT based on a rule comprises: selecting at least one of:

lowest priority CAPC of at least one logical channel with medium access control (MAC) SDU multiplexed in a MAC protocol data unit (PDU) for SDT;

lowest priority CAPC of at least one dedicated traffic channel (DTCH) logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest priority CAPC if only at least one MAC control element (CE) for SDT is included;

highest priority CAPC if at least one MAC CE for SDT is included;

highest or lowest priority CAPC of at least one CCCH and/or at least one DCCH and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one CCCH and/or at least one DCCH and at least one MAC CE and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one CCCH and/or at least one DCCH and at least one dedicated traffic channel (DTCH) logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one CCCH and/or at least one DCCH and at least one MAC CE and at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of all parts which are multiplexed in the MAC PDU for SDT;

highest or lowest priority;

highest or lowest priority CAPC of at least one CCCH(s) and at least one MAC CE multiplexed in the MAC PDU for SDT;

highest or lowest priority if CCCH SDU(s) carrying signaling radio bearer (SRB)0 is included for SDT;

highest or lowest priority CAPC of at least one MAC CE and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT; or

highest or lowest priority CAPC of at least one MAC CE and at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT.

5 . The method of claim 4 , further comprising: re-assembling the MAC PDU including only a highest priority CAPC part in a previous MAC PDU if a consistent listen before talk (LBT) failure for SDT is triggered.

6 . A base station (BS) for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the BS to:

receive uplink (UL) small data transmission (SDT) from a user equipment (UE);

select a channel access priority class (CAPC) to be used for downlink (DL) SDT based on a rule; and

wherein the UL SDT is based on the selected CAPC for uplink (UL) SDT during at least configured grant (CG) based SDT, and wherein receiving the CAPC to be used for SDT based on a rule comprises receiving a highest or lowest priority CAPC of at least one common control channel (CCCH) if the CCCH or at least one dedicated control channel (DCCH) service data unit (SDU) or MAC CE is included for SDT.

7 . The BS of claim 6 , wherein the at least one processor is configured to cause the BS to: transmit information of the CAPC for SDT by a system broadcast message or radio resource control (RRC) signaling.

8 . The BS of claim 7 , wherein the information of the CAPC for SDT is used for one or more of:

at least one of signaling radio bearer (SRB)0, SRB1, and SRB3;

assistant information for SDT and at least one of SRB0, SRB1, and SRB3;

logical channel including assistant information for SDT;

an entire SDT message;

data part of SDT or each dedicated traffic channel (DTCH) logical channel;

each logical channel;

medium access control (MAC) control element (CE); or

data radio bearer (DRB).

9 . The BS of claim 6 , wherein to select the CAPC to be used for the DL SDT based on the rule comprises: use an equivalent priority CAPC with the received UL SDT.

10 . The BS of claim 6 , wherein to select the CAPC to be used for DL SDT based on the rule comprises: select at least one of:

lowest priority CAPC of at least one logical channel with MAC SDU multiplexed in a MAC PDU for SDT;

lowest priority CAPC of at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest priority CAPC if only at least one MAC CE for SDT is included;

highest priority CAPC if at least one MAC CE for SDT is included;

highest or lowest priority CAPC of at least one DCCH and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one DCCH and at least one MAC CE and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one DCCH and at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one DCCH and at least one MAC CE and at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of all parts which are multiplexed in the MAC PDU for SDT;

highest or lowest priority;

highest or lowest priority CAPC of at least one DCCH and at least one MAC CE multiplexed in the MAC PDU for SDT;

highest or lowest priority CAPC of at least one MAC CE and at least one logical channel with MAC SDU multiplexed in the MAC PDU for SDT; or

highest or lowest priority CAPC of at least one MAC CE and at least one DTCH logical channel with MAC SDU multiplexed in the MAC PDU for SDT.

11 . A user equipment (UE) for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the UE to:

select a channel access priority class (CAPC) to be used for small data transmission (SDT) based on a rule if the CAPC for SDT is not indicated by a base station;

perform SDT based on the CAPC for SDT; and

12 . The UE of claim 11 , wherein the at least one processor is configured to cause the UE to: receive information of the CAPC for SDT by a system broadcast message or radio resource control (RRC) signaling or predefining the CAPC for SDT.

13 . The UE of claim 12 , wherein the at least one processor is configured to cause the UE to: receive the information of the CAPC for SDT in a configuration message of the SDT.

14 . The UE of claim 12 , wherein the information of the CAPC for SDT is used for one or more of:

at least one of signaling radio bearer (SRB)0, SRB1, and SRB3;

assistant information for SDT and at least one of SRB0, SRB1, and SRB3;

logical channel including assistant information for SDT;

an entire SDT message;

data part of SDT or each dedicated traffic channel (DTCH) logical channel;

each logical channel;

medium access control (MAC) control element (CE); or

data radio bearer (DRB).

15 . The UE of claim 11 , wherein to select the CAPC to be used for SDT based on a rule is to select at least one of: