Methods for PDU session interworking across EPS and 5GS for NB-IoT
Disclosed is a method of managing PDU session inter-working in a User Equipment, UE, wherein if the UE changes from WB-N1 mode to NB-S1 mode, then the UE sets the state of any dedicated EPS bearer context to be inactive.
1 . A method performed by a User Equipment (UE) in a wireless communication system, the method comprising:
changing a mode of the UE operating in a single registration mode from a WB-N1 mode to an NB-S1 mode in an idle mode;
upon changing the mode of the UE operating in the single registration mode from the WB-N1 mode to the NB-S1 mode in the idle mode, setting a state of a dedicated evolved packet system (EPS) bearer context to be inactive;
after setting the state of the dedicated EPS bearer context to be inactive, including an EPS bearer context status information element (IE) in a tracking area update (TAU) request message; and
upon changing the mode of the UE operating in the single registration mode from the WB-N1 mode to the NB-S1 mode in the idle mode, locally deactivating a dedicated EPS bearer.
2 . The method of claim 1 , further comprising:
deleting any associated quality of service (QoS) rule and QoS flow descriptions associated with the dedicated EPS bearer.
3 . The method of claim 1 , further comprising:
determining that an EPS bearer is a dedicated EPS bearer in case that an EPS bearer identity is associated with a quality of service (QoS) flow description that is in turn associated with a QoS rule that is not the default QoS rule.
4 . The method of claim 1 , further comprising:
determining a number of protocol data unit (PDU) sessions that are active, and
in case that the number of the PDU sessions is more than a total number of Data Radio Bearers (DRBs), that the UE supports in an NB-S1 mode, maintaining a maximum number of the PDU sessions that is equal to the maximum number of PDU session that is equal to the maximum number of DRBs that the UE supports in the NB-S1 mode.
5 . A user equipment (UE) in a wireless communication system, comprising:
transceiver; and
at least one processor configured to:
change a mode of the UE operating in a single registration mode from a WB-N1 mode to an NB-S1 mode in an idle mode,
upon changing the mode of the UE operating in the single registration mode from the WB-N1 mode to the NB-S1 mode in the idle mode, set a state of a dedicated evolved packet system (EPS) bearer context to be inactive,
after setting the state of the dedicated EPS bearer context to be inactive, include an EPS bearer context status information element (IE) in a tracking area update (TAU) request message, and
upon changing the mode of the UE operating in the single registration mode from the WB-N1 mode to the NB-S1 mode in the idle mode, locally deactivating a dedicated EPS bearer.
6 . The UE of claim 5 , wherein the at least one processor is further configured to:
delete any associated quality of service (QoS) rule and QoS flow descriptions associated with the dedicated EPS bearer.
7 . The UE of claim 5 , wherein the at least one processor is further configured to:
determine that an EPS bearer is a dedicated EPS bearer in case that an EPS bearer identity is associated with a quality of service (QoS) flow description that is in turn associated with a QoS rule that is not the default QoS rule.
8 . The UE of claim 5 , wherein the at least one processor is further configured to:
determine a number of protocol data unit (PDU) sessions that are active, and
in case that the number of the PDU sessions is more than a total number of Data Radio Bearers (DRBs) that the UE supports in an NB-S1 mode, maintain a maximum number of the PDU sessions that is equal to the maximum number of PDU session that is equal to the maximum number of DRBs that the UE supports in the NB-S1 mode.
9 . The UE of claim 5 , wherein the at least one processor is further configured to:
in case that the UE has deactivated any dedicated EPS bearer, send a Tracking Area Update (TAU) Request message including the EPS bearer context status information element (IE).