Communication method, apparatus, and system

1. A communication method, comprising:

sending, by a first entity in a centralized unit control plane (CU-CP), an access request of a terminal to a second entity in the CU-CP;

determining, by the second entity based on the access request, whether to allow access of the terminal;

sending, by the second entity and based on a determination result of whether to allow access of the terminal, an access response to the first entity;

in response to determining that the access response indicates that access of the terminal is allowed, sending, by the first entity, a radio bearer setup request to the second entity;

determining, by the second entity, whether to allow setup of a radio bearer (RB) to the terminal;

sending, by the second entity and based on a determination result of whether to allow setup of the RB to the terminal, a radio bearer setup response to the first entity; and

in response to determining that the radio bearer setup response indicates that setup of the RB to the terminal is allowed, triggering, by the first entity, setup of the RB to the terminal.

2. The method according to claim 1 , wherein the access request further comprises one or more of the following information: a quantity of terminals that access a base station to which the first entity belongs, identifiers of one or more cells covered by the base station, or a quantity of terminals that access the one or more cells.

3. The method according to claim 1 , wherein after the sending, by the first entity, the access request of the terminal to the second entity, the method further comprises:

receiving, by the first entity, a release request sent by the second entity, wherein the release request comprises an identifier of another terminal and a serving cell identifier of the another terminal; and

releasing, by the first entity, a resource of the another terminal based on the release request.

4. The method according to claim 1 , wherein the access request comprises RB information that is obtained from a distributed unit (DU) and managed by the DU.

5. The method according to claim 4 , wherein after the sending, by the first entity, the radio bearer setup request to the second entity, the method further comprises:

sending, by the second entity, an RB release request to the first entity, wherein the RB release request comprises one or more of the following information: an identifier of a to-be-released terminal, a serving cell identifier of the to-be-released terminal, and information about a to-be-released RB; and

releasing, by the first entity, an RB of the to-be-released terminal based on the RB release request.

6. The method according to claim 1 , further comprising:

sending, by the second entity, a handover indication to the first entity, wherein the handover indication is used to request to hand over a terminal that accesses the second entity to a second entity in a neighboring CU-CP; and

handing over, by the first entity according to the handover indication, the terminal that accesses the second entity to the second entity in the neighboring CU-CP.

7. The method according to claim 6 , wherein before the sending, by the second entity, the handover indication to the first entity, the method further comprises:

receiving, by the first entity, a measurement report sent by the terminal; and

sending, by the first entity, the measurement report to the second entity.

8. The method according to claim 6 , wherein the handover indication comprises one or more of the following information: an identifier of a to-be-handed-over terminal, an identifier of a target cell, and target frequency information.

9. The method according to claim 1 , further comprising:

sending, by the first entity, a cell congestion status report to the second entity;

sending, by the second entity, a cell congestion relieve request to the first entity, wherein the cell congestion relieve request comprises a relieving policy; and

performing, by the first entity, congestion relieving processing based on the relieving policy.

10. The method according to claim 9 , wherein before the sending, by the first entity, the cell congestion status report to the second entity, the method further comprises:

receiving, by the first entity, configuration update information sent by a DU; and

determining, by the first entity based on the configuration update information, cell congestion managed by the first entity.

11. The method according to claim 9 , wherein the cell congestion status report comprises one or more of the following information: an identifier of a cell, a bearer type, an allocation retention priority (ARP), a congestion type, or a congestion level.

12. The method according to claim 1 , further comprising:

sending, by the first entity, a cell status report to the second entity; and

determining, by the second entity based on the cell status report, whether to perform load balancing.

13. The method according to claim 12 , wherein the cell status report comprises one or more of the following information: an identifier of a cell, a quantity of terminals in the cell, a downlink capacity of the cell, uplink and downlink physical resource block usage of the cell, uplink and downlink physical resource block usage of a guaranteed bit rate of the cell, uplink and downlink physical resource block usage of a non-guaranteed bit rate of the cell, a hardware load level, and a transmission load level.

14. The method according to claim 12 , wherein in response to the determination that the second entity determines to perform load balancing, the method further comprises:

sending, by the second entity, a request of obtaining information about a neighboring cell to the first entity;

sending, by the first entity, the information about the neighboring cell to the second entity;

sending, by the second entity, a terminal release control message to the first entity; and

performing, by the first entity, reselection priority control based on the terminal release control message.

15. The method according to claim 14 , wherein the information about the neighboring cell comprises one or more of the following information: a serving cell identifier, an identifier of the neighboring cell, a quantity of terminals in the neighboring cell, uplink and downlink physical resource block usage of the neighboring cell, uplink and downlink physical resource block usage of a guaranteed bit rate of the neighboring cell, uplink and downlink physical resource block usage of a non-guaranteed bit rate of the neighboring cell, a hardware load level of the neighboring cell, or a transmission load level of the neighboring cell.

16. The method according to claim 14 , wherein the terminal release control message comprises one or more of the following information: an identifier of a cell, a quantity of to-be-released terminals, or a frequency on which camping is preferentially performed.

17. The method according to claim 14 , wherein after the sending, by the first entity, the information about the neighboring cell to the second entity, the method further comprises:

sending, by the second entity, a terminal selection policy control message to the first entity, wherein the terminal selection policy control message comprises one or more of the following information: an identifier of a cell, a quantity of connected-mode terminals to be triggered to perform measurement, and frequency information whose measurement is to be triggered;

triggering, by the first entity based on the terminal selection policy control message, the terminal to perform measurement;

sending, by the first entity, a terminal selection result report to the second entity after receiving a measurement report from the terminal, wherein the terminal selection result report comprises one or more of the following information: an identifier of a cell, a terminal list, and the measurement report of the terminal;

determining, by the second entity, a to-be-handed-over terminal based on the terminal selection result report;

sending, by the second entity, a handover control message to the first entity; and

handing over, by the first entity, the to-be-handed-over terminal based on the handover control message.

18. The method according to claim 17 , wherein the handover control message comprises one or more of the following information: a serving cell identifier, an identifier of the terminal, and a list of target neighboring cells.

19. An apparatus, comprising at least one processor, and one or more memories coupled the at least one processor, wherein:

the one or more memories store programming instructions for execution by the at least one processor to: send, by a first entity in a centralized unit control plane (CU-CP), an access request of a terminal to a second entity in the CU-CP;

determine, by the second entity based on the access request, whether to allow access of the terminal;

send, by the second entity, an access response to the first entity based on a determination result of whether to allow access of the terminal;

in response to determining that the access response indicates that access of the terminal is allowed, send, by the first entity, a radio bearer setup request to the second entity;

determine, by the second entity, whether to allow setup of a radio bearer (RB) to the terminal;

send, by the second entity, a radio bearer setup response to the first entity based on a determination result of whether to allow setup of the RB to the terminal; and

in response to determining that the radio bearer setup response indicates that setup of the RB to the terminal is allowed, triggering, by the first entity, setup of the RB to the terminal.

20. A non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer-executable instructions for execution by at least one processor to:

send, by a first entity in a centralized unit control plane (CU-CP), an access request of a terminal to a second entity in the CU-CP;

determine, by the second entity based on the access request, whether to allow access of the terminal;

send, by the second entity, an access response to the first entity based on a determination result of whether to allow access of the terminal;

in response to determining that the access response indicates that access of the terminal is allowed, send, by the first entity, a radio bearer setup request to the second entity;

determine, by the second entity, whether to allow setup of a radio bearer (RB) to the terminal;

send, by the second entity, a radio bearer setup response to the first entity based on a determination result of whether to allow setup of the RB to the terminal; and

in response to determining that the setup response indicates that setup of the RB to the terminal is allowed, triggering, by the first entity, setup of the RB to the terminal.