Release cause for transition from connected state

1. A method for handling communications from one or more network nodes in a radio access network (RAN), the method comprising:

receiving by a user equipment that is operating in a connected state, a radio resource control (RRC) release message from a network node;

determining, based on an indication in the RRC release message, whether to suspend the user equipment to an inactive state or an idle state, the indication comprising a presence or absence a suspend configuration field in the RRC release message;

applying delta signaling corresponding to a suspend configuration indicated by the suspend configuration field; and

responsive to determining that the indication is to suspend to an inactive state, transitioning the user equipment to the inactive state.

2. The method of claim 1 , wherein the indication to suspend the user equipment to the inactive state comprises the presence of a suspend configuration field in the RRC release message.

3. The method of claim 1 , wherein the indication to suspend the user equipment to the idle state comprises the absence of a suspend configuration field in the RRC release message.

4. The method of claim 1 , wherein the suspend configuration field indicates a configuration corresponding to the inactive state.

5. The method of claim 1 , wherein applying delta signaling comprises:

receiving changed suspend configuration information indicated by the suspend configuration field; and

accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.

6. The method of claim 1 , wherein the suspend configuration includes RAN Notification Area (RNA) information.

7. The method of claim 1 , wherein the transitioning of the user equipment to the inactive state is performed during a connection of the user equipment to a 5G core network from a long term evolution (LTE) network.

8. A computer program product comprising a non-transitory computer readable medium storing computer readable program code, the computer readable program code operable, when executed by processing circuitry to perform operations comprising:

receiving by a user equipment that is operating in a connected state, a radio resource control (RRC) release message from a network node;

determining, based on an indication in the RRC release message, whether to suspend the user equipment to an inactive state or an idle state, the indication comprising a presence or absence a suspend configuration field in the RRC release message;

applying delta signaling corresponding to a suspend configuration indicated by the suspend configuration field; and

responsive to determining that the indication is to suspend to an inactive state, transitioning the user equipment to the inactive state.

9. The computer program product of claim 8 , wherein the indication to suspend the user equipment to the inactive state comprises the presence of a suspend configuration field in the RRC release message.

10. The computer program product of claim 8 , wherein the indication to suspend the user equipment to the idle state comprises the absence of a suspend configuration field in the RRC release message.

11. The computer program product of claim 8 , wherein the suspend configuration field indicates a configuration corresponding to the inactive state.

12. The computer program product of claim 8 , wherein applying delta signaling comprises:

receiving changed suspend configuration information indicated by the suspend configuration field; and

accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.

13. The computer program product of claim 8 , wherein the suspend configuration includes RAN Notification Area (RNA) information.

14. The computer program product of claim 8 , wherein the transitioning of the user equipment to the inactive state is performed during a connection of the user equipment to a 5G core network from a long term evolution (LTE) network.

15. A system for handling communications in a radio access network (RAN), the system comprising:

a non-transitory memory; and

processing circuitry coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to cause the system to perform operations comprising:

receiving by a user equipment that is operating in a connected state, a radio resource control (RRC) release message from a network node;

determining, based on an indication in the RRC release message, whether to suspend the user equipment to an inactive state or an idle state, the indication comprising a presence or absence a suspend configuration field in the RRC release message;

applying delta signaling corresponding to a suspend configuration indicated by the suspend configuration field; and

responsive to determining that the indication is to suspend to an inactive state, transitioning the user equipment to the inactive state.

16. The system of claim 15 , wherein the indication to suspend the user equipment to the inactive state comprises the presence of a suspend configuration field in the RRC release message.

17. The system of claim 15 , wherein the indication to suspend the user equipment to the idle state comprises the absence of a suspend configuration field in the RRC release message.

18. The system of claim 15 , wherein the suspend configuration field indicates a configuration corresponding to the inactive state.

19. The system of claim 15 , wherein applying delta signaling comprises:

receiving changed suspend configuration information indicated by the suspend configuration field; and

accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.

20. The system of claim 15 , wherein the suspend configuration includes RAN Notification Area (RNA) information.