Overload control method in wireless communication system and device for same

1. A method for performing, by a base station, an overload control in a wireless communication system, the method comprising:

receiving from a core network an overload start message;

determining whether to apply an overload control for a control plane (CP); and

based the overload control for the CP being determined to apply, transmitting, to a user equipment (UE), a RRC connection release message for commanding a release of a RRC connection;

wherein determining whether to apply the overload control for the CP comprises:

based on the overload control for the CP being performed during a service request procedure:

receiving, from the UE, a radio resource control (RRC) message with a Control Plane Service Request (CPSR) message,

wherein the RRC message with the CPSR message includes (i) first information representing that the UE supports only CP Cellular Internet of Things (IoT) (CIoT) evolved packet system (EPS) optimization or (ii) second information representing a data transmission via the CP CIoT EPS optimization, and

wherein a decision as to whether to apply the overload control for the CP is determined based on (i) the first information or (ii) the second information,

based on the overload control being performed during a tracking area update (TAU) procedure:

receiving, from the UE, a RRC message with a TAU request message,

wherein the RRC message with the TAU request message includes third information representing the data transmission via the CP CIoT EPS optimization based on the TAU request message being a TAU request message with signalling active flag, and

wherein a decision as to whether to apply the overload control for the CP is determined based on the third information.

2. The method of claim 1 , further comprising:

receiving from the UE a RRC message with a RRC establishment cause,

wherein the RRC establishment cause is mobile originated (MO) data or mo-signalling or delayTolerantAccess data.

3. The method of claim 1 , wherein the RRC connection release message includes a wait time for a user data access via the control plane.

4. The method of claim 1 , wherein, based on the RRC message with the CPSR message including the second information, the RRC message with the CPSR message further includes information representing use of the CP CIoT EPS optimization.

5. The method of claim 4 , wherein based on the UE being a UE using narrowband (NB)-IoT radio access technology (RAT), the indication of requesting the use of the CIoT EPS optimization is used.

6. The method of claim 4 , wherein, based on the RRC message with the CPSR message including the second information, the second information is considered as the CP CIoT EPS optimization related to a data transmission via the CP.

7. The method of claim 6 , wherein, based on the RRC message with the CPSR message including information representing the CP CIoT EPS optimization, the information representing the CP CIoT EPS optimization is considered as the CP CIoT EPS optimization unrelated to the data transmission via the CP.

8. A method for operating a user equipment (UE) for an overload control in a wireless communication system, the method comprising:

based on the overload control for a control plane (CP) being determined to apply, transmitting, from a base station, a RRC connection release message for commanding a release of a RRC connection;

based on the overload control for the CP being performed during a service request procedure, further comprising:

transmitting, to the base station, a radio resource control (RRC) message with a Control Plane Service Request (CPSR) message,

wherein the RRC message with the CPSR message includes (i) first information representing that the UE supports only CP Cellular Internet of Things (IoT) (CIoT) evolved packet system (EPS) optimization or (ii) second information representing a data transmission via the CP CIoT EPS optimization, and

wherein a decision as to whether to apply the overload control for the CP is determined based on (i) the first information or (ii) the second information,

based on the overload control being performed during a tracking area update (TAU) procedure further comprising:

transmitting, to the base station, a RRC message with a TAU request message,

wherein the RRC message with the TAU request message includes third information representing the data transmission via the CP CIoT EPS optimization based on the TAU request message being a TAU request message with signalling active flag, and

wherein a decision as to whether to apply the overload control for the CP is determined based on the third information.

9. The method of claim 8 , further comprising:

transmitting, to the base station, a RRC message with a RRC establishment cause to the base station,

wherein the RRC establishment cause is mobile originated (MO) data or delayTolerantAccess data.

10. The method of claim 8 , wherein the RRC connection release message includes a wait time for a user data access via the control plane.

11. The method of claim 8 , wherein, based on the RRC message with the CPSR message including the second information, the RRC message with the CPSR message further includes information representing use of the CP CIoT EPS optimization.

12. The method of claim 11 , wherein based on the UE being a UE using narrowband (NB)-IoT radio access technology (RAT), the indication of requesting the use of the CIoT EPS optimization is used.

13. The method of claim 11 , wherein, based on the RRC message with the CPSR message including the second information, the second information is considered as the CP CIoT EPS optimization related to a data transmission via the CP.

14. The method of claim 13 , wherein, based on the RRC message with the CPSR message including information representing the CP CIoT EPS optimization, the information representing the CP CIoT EPS optimization is considered as the CP CIoT EPS optimization unrelated to the data transmission via the CP.