Communication method and device
An access network device receives a first cycle from a core network device, where the first cycle is a maximum eDRX cycle that can be configured for a first terminal device, and the first cycle is used by the first terminal device in RRC inactive state. The access network device determines a second cycle based on the first cycle, where the second cycle is an eDRX cycle configured for the first terminal device, the second cycle is used by the first terminal device in RRC inactive state, and a length of the second cycle is less than or equal to a length of the first cycle. The access network device sends a second message to the core network device, where the second message includes the second cycle.
1 . A method, comprising:
determining, by a core network device, a first cycle based on non-access stratum (NAS) timing information, wherein the first cycle is a maximum extended discontinuous reception (eDRX) cycle that is allowed to be configured for a first terminal device, and the first cycle is able to be used by the first terminal device in a radio resource control (RRC) inactive state;
sending, by the core network device, an initial context setup request message to an access network device in a registration process of the first terminal device, wherein the initial context setup request message comprises context information of the first terminal device, and the initial context setup request message further comprises information of the first cycle;
receiving, by the access network device, the initial context setup request message, and determining a second cycle based on the information of the first cycle carried in the initial context setup request message, wherein the second cycle is an eDRX cycle configured for the first terminal device, the second cycle is able to be used by the first terminal device in the RRC inactive state, and a length of the second cycle is less than or equal to a length of the first cycle;
sending, by the access network device, an initial context setup response message to the core network device, wherein the initial context setup response message comprises information of the second cycle;
starting, by the access network device, an RRC connection release timer when the first terminal device completes registration and the access network device does not detect data transmission of the first terminal device;
when the RRC connection release timer expires, sending, by the access network device, an RRC connection release message to the first terminal device, wherein the RRC connection release message comprises the information of the second cycle; and
when the first terminal device is in the RRC inactive state, monitoring, by the first terminal device, paging according to the second cycle.
2 . A method, comprising:
receiving, by an access network device, a first message from a core network device, wherein the first message comprises information of a first cycle, the first cycle is determined based on non-access stratum (NAS) timing information, the NAS timing information comprises a minimum retransmission time interval of a NAS message or a maximum number of retransmissions of the NAS message, the first cycle is a maximum extended discontinuous reception (eDRX) cycle that is allowed to be configured for a first terminal device, and the first cycle is able to be used by the first terminal device in a radio resource control (RRC) inactive state;
determining, by the access network device, a second cycle based on the first cycle, wherein the second cycle is an eDRX cycle configured for the first terminal device, the second cycle is able to be used by the first terminal device in RRC inactive state, and a length of the second cycle is less than or equal to a length of the first cycle; and
sending, by the access network device, a second message to the core network device, wherein the second message comprises information of the second cycle, and wherein:
the second message is an initial context setup response message; or
the second message is an RRC inactive transition report; or
the second message is an Access and Mobility Management Function (AMF) configuration update acknowledgment message.
3 . The method according to claim 2 , wherein:
the first message is an initial context setup request message.
4 . The method according to claim 2 , further comprising:
sending, by the access network device, a third message to the first terminal device, wherein the third message comprises the information of the second cycle.
5 . The method according to claim 4 , wherein the third message is an RRC connection release message, and the RRC connection release message indicates to the first terminal device to transition to the RRC inactive state.
6 . The method according to claim 2 , wherein lengths of eDRX cycles that are configured, based on the first cycle, by the access network device for different terminal devices to use in the RRC inactive state are different.
7 . The method according to claim 2 , wherein the first terminal device is a reduced capability (redcap) UE.
8 . The method according to claim 2 , wherein:
the first message is an AMF configuration update message, and the second message is the AMF configuration update acknowledgment message; or
the first message is an next generation (NG) setup response message.
9 . The method according to claim 2 , further comprising:
sending, by the access network device, a third message to a second terminal device, wherein the third message comprises information of a third cycle, a length of the third cycle is less than or equal to the length of the second cycle, the third cycle is an eDRX cycle configured for the second terminal device, and the third cycle is able to be used by the second terminal device in the RRC inactive state; and
sending, by the access network device, a fourth message to a third terminal device, wherein the fourth message comprises information of a fourth cycle, a length of the fourth cycle is less than or equal to the length of the second cycle, the fourth cycle is an eDRX cycle configured for the second terminal device, and the fourth cycle is able to be used by the second terminal device in the RRC inactive state; and
wherein the length of the third cycle is the same as or different from the length of the fourth cycle, and the first terminal device is a plurality of first terminal devices, and the second terminal device and the third terminal device belong to the plurality of first terminal devices.
10 . The method according to claim 2 , wherein lengths of the second cycle determined by the access network device for different terminal devices based on the first cycle are different.
11 . The method according to claim 5 , further comprising:
starting, by the access network device, an RRC connection release timer when the first terminal device completes registration and the access network device does not detect data transmission of the first terminal device; and
wherein sending, by the access network device, the third message to the first terminal device comprises:
when the RRC connection release timer expires, sending, by the access network device, the RRC connection release message to the first terminal device, wherein the RRC connection release message comprises the information of the second cycle.
12 . A method, comprising:
sending, by a core network device, a first message to an access network device, wherein the first message comprises a first cycle, the first cycle is determined based on non-access stratum (NAS) timing information, the NAS timing information comprises a minimum retransmission time interval of a NAS message or a maximum number of retransmissions of the NAS message, the first cycle is a maximum extended discontinuous reception (eDRX) cycle that is allowed to be configured for a first terminal device, and the first cycle is able to be used by the first terminal device in a radio resource control (RRC) inactive state; and
receiving, by the core network device, a second message from the access network device, wherein the second message comprises information of a second cycle, the second cycle is an eDRX cycle configured for the first terminal device, the second cycle is able to be used by the first terminal device in the RRC inactive state, and a length of the second cycle is less than or equal to a length of the first cycle, and wherein:
the second message is an initial context setup response message; or
the second message is an RRC inactive transition report; or
the second message is an Access and Mobility Management Function (AMF) configuration update acknowledgment message.
13 . The method according to claim 12 , wherein:
the first message is an initial context setup request message.
14 . The method according to claim 12 , further comprising:
receiving, by the core network device, an RRC inactive transition report from the access network device, wherein the RRC inactive transition report indicates that the first terminal device enters the RRC inactive state; and
sending, by the core network device, a NAS message to the first terminal device according to the second cycle.
15 . The method according to claim 12 , wherein the first terminal device is a reduced capability (redcap) UE.
16 . The method according to claim 12 , wherein:
the first message is an AMF configuration update message, and the second message is the AMF configuration update acknowledgment message; or
the first message is a next generation (NG) setup response message.
17 . The method according to claim 12 , further comprising:
receiving, by the core network device, an RRC inactive transition report from the access network device, wherein the RRC inactive transition report indicates that the first terminal device enters the RRC inactive state; and
sending, by the core network device, a non-access stratum (NAS) message to the first terminal device according to the second cycle, wherein the first terminal device is covered by the access network device.