User equipment and method executed thereby, base station and method executed thereby, and mobile control entity and method executed 1HEREBY

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

receiving a paging message from a base station;

initiating a Radio Resource Control (RRC) connection establishment procedure or an RRC connection resume procedure based on the paging message; and

when initiating the RRC connection establishment procedure or the RRC connection resume procedure, determining whether to perform a downlink early data transmission (EDT) preparation operation based on downlink EDT indication information included in the paging message and based on an establishment cause for initiating the RRC connection establishment procedure or the RRC connection resume procedure, wherein

the downlink EDT indication information comprises a downlink EDT UE identity list included in the paging message; and

when a UE identity of the UE is included in the downlink EDT UE identity list, the UE performs the downlink EDT preparation operation.

2. The method according to claim 1 , wherein:

the downlink EDT preparation operation is performed when the downlink EDT indication information is included in the paging message; and

the downlink EDT preparation operation is not performed when the downlink EDT indication information is not included in the paging message.

3. The method according to claim 1 , wherein the downlink EDT indication information comprises an integer represented by M bits and corresponding to an entry in the downlink EDT UE identity list included in the paging message.

4. The method according to claim 1 , wherein the downlink EDT preparation operation comprises at least one of the following:

restoring a Packet Data Convergence Protocol (PDCP) state corresponding to at least one of a Data Radio Bearer (DRB) and a Signal Radio Bearer (SRB);

re-establishing a PDCP entity for the at least one of the DRB and the SRB;

if a drb-continueROHC indication is provided in a most recent RRC connection release message and if the UE initiates the RRC connection establishment procedure or the RRC connection resume procedure within a same cell, then indicating to a lower layer that a stored UE access stratum context is used and drb-continueROHC is configured and continuing a header compression protocol context for the DRB configured with a header compression protocol;

if the drb-continueROHC indication is not provided in the most recent RRC connection release message or if the UE initiates the RRC connection establishment procedure or the RRC connection resume procedure within a different cell, then indicating to the lower layer that the stored UE access stratum context is used and resetting the header compression protocol context for the DRB configured with the header compression protocol;

resuming the at least one of the DRB and the SRB;

using a stored Next Hop Chaining Counter (NCC) value and deriving a K eNB key based on a K ASME key associated with a current K eNB key;

deriving a KRRCint key associated with a previously configured integrity algorithm;

deriving a KRRCenc key and a KUPenc key associated with a previously configured encryption algorithm;

configuring the lower layer to use the previously configured integrity algorithm and the derived KRRCint key to resume integrity protection for a subsequent message received and transmitted by the UE;

configuring the lower layer to use the previously configured encryption algorithm and the derived KRRCenc key to resume encryption/decryption for the subsequent message received and transmitted by the UE;

configuring the lower layer to use the previously configured encryption algorithm and the derived KUPenc key to immediately resume encryption/decryption for user data received or transmitted by the UE;

resuming security; and

configuring the lower layer to use EDT.

5. The method according to claim 1 , wherein:

determining whether to perform the downlink EDT preparation operation is further based on a value associated with the downlink EDT indication information;

the downlink EDT preparation operation is performed when the value of the downlink EDT indication information is 1 or TRUE; and

the downlink EDT preparation operation is not performed when the value of the downlink EDT indication information is 0 or not set to TRUE.

6. The method according to claim 1 , wherein:

the downlink EDT preparation operation is performed when the establishment cause is a mobile terminated access, and the downlink EDT preparation operation is not performed when the establishment cause is not a mobile terminated access.

7. A user equipment (UE) comprising:

at least one processor; and

at least one memory coupled to the at least one processor and storing computer-executable instructions that, when executed by the at least one processor, cause the UE to perform operations comprising:

receiving a paging message from a base station;

initiating a Radio Resource Control (RRC) connection establishment procedure or an RRC connection resume procedure based on the paging message; and

when initiating the RRC connection establishment procedure or the RRC connection resume procedure, determining whether to perform a downlink early data transmission (EDT) preparation operation based on downlink EDT indication information included in the paging message and based on an establishment cause for initiating the RRC connection establishment procedure or the RRC connection resume procedure, wherein

the downlink EDT indication information comprises a downlink EDT UE identity list included in the paging message; and

when a UE identity of the UE is included in the downlink EDT UE identity list, the UE performs the downlink EDT preparation operation.

8. The UE according to claim 7 , wherein:

the downlink EDT preparation operation is performed when the downlink EDT indication information is included in the paging message; and

the downlink EDT preparation operation is not performed when the downlink EDT indication information is not included in the paging message.

9. The UE according to claim 7 , wherein the downlink EDT indication information comprises an integer represented by M bits and corresponding to an entry in the downlink EDT UE identity list included in the paging message.

10. The UE according to claim 7 , wherein the downlink EDT preparation operation comprises at least one of the following:

restoring a Packet Data Convergence Protocol (PDCP) state corresponding to at least one of a Data Radio Bearer (DRB) and a Signal Radio Bearer (SRB);

re-establishing a PDCP entity for the at least one of the DRB and the SRB;

if a drb-continueROHC indication is provided in a most recent RRC connection release message and if the UE initiates the RRC connection establishment procedure or the RRC connection resume procedure within a same cell, then indicating to a lower layer that a stored UE access stratum context is used and drb-continueROHC is configured and continuing a header compression protocol context for the DRB configured with a header compression protocol;

if the drb-continueROHC indication is not provided in the most recent RRC connection release message or if the UE initiates the RRC connection establishment procedure or the RRC connection resume procedure within a different cell, then indicating to the lower layer that the stored UE access stratum context is used and resetting the header compression protocol context for the DRB configured with the header compression protocol;

resuming the at least one of the DRB and the SRB;

using a stored Next Hop Chaining Counter (NCC) value and deriving a K eNB key based on a K ASME key associated with a current K eNB key;

deriving a KRRCint key associated with a previously configured integrity algorithm;

deriving a KRRCenc key and a KUPenc key associated with a previously configured encryption algorithm;

configuring the lower layer to use the previously configured integrity algorithm and the derived KRRCint key to resume integrity protection for a subsequent message received and transmitted by the UE;

configuring the lower layer to use the previously configured encryption algorithm and the derived KRRCenc key to resume encryption/decryption for the subsequent message received and transmitted by the UE;

configuring the lower layer to use the previously configured encryption algorithm and the derived KUPenc key to immediately resume encryption/decryption for user data received or transmitted by the UE;

resuming security; and

configuring the lower layer to perform EDT.

11. The UE according to claim 7 , wherein:

determining whether to perform the downlink EDT preparation operation is further based on a value associated with the downlink EDT indication information;

the downlink EDT preparation operation is performed when the value of the downlink EDT indication information is 1 or TRUE; and

the downlink EDT preparation operation is not performed when the value of the downlink EDT indication information is 0 or not set to TRUE.

12. The UE according to claim 7 , wherein:

the downlink EDT preparation operation is performed when the establishment cause is a mobile terminated access, and

the downlink EDT preparation operation is not performed when the establishment cause is not a mobile terminated access.

13. A base station comprising:

at least one processor; and

at least one memory coupled to the at least one processor and storing configured to store computer-executable instructions that, when executed by the at least one processor, cause the base station to perform operations comprising:

receiving a paging message for a user equipment (UE) from a mobility management entity (MME), the paging message including first downlink data volume size information for a downlink transmission associated with current paging;

determining whether a downlink data transmission is performed by adopting a downlink early data transmission (EDT) according to the first downlink data volume size information;

transmitting the paging message to the UE; and

indicating to the UE via downlink EDT indication information whether to perform a downlink EDT preparation operation when a Radio Resource Control (RRC) connection establishment procedure or an RRC connection resume procedure is initiated by the UE based on the paging message.

14. The base station according to claim 13 , wherein the MME is configured to:

receive a downlink data notification message from a serving gateway, the downlink data notification message including second downlink data volume size information; and

transmit the paging message for the UE to the base station, wherein:

the paging message includes the first downlink data volume size information for the downlink transmission associated with the current paging; and

the first downlink data volume size information is determined based on the second downlink data volume size information.