Granted Patent B2

US 12,750,754 · App. 17/999,539 · Granted Sep 29, 2026

Inventor: Mahmoud Watfa (Staines, GB)

Assignee: Samsung Electronics Co., Ltd.

H04W36/32H04W36/0022H04W36/0079

Abstract

Claims (75)

1 . A method performed by a user equipment (UE), in a communication system, the method comprising:

transmitting a service request message;

in case that the service request message is transmitted to an access and mobility management function (AMF):

receiving, from the AMF, a first service reject message including a fifth generation (5G) mobility management (5GMM) cause value of #31, and

identifying that redirection to an evolved packet core (EPC) is required based on the 5GMM cause value; and

in case that the service request message is transmitted to a mobility management entity (MME):

receiving, from the MME, a second service reject message including an EPC mobility management (EMM) cause value of #31, and

identifying that redirection to a 5G core network (5GCN) is required based on the EMM cause value.

2 . The method of claim 1 , further comprising:

setting, based on the 5GMM cause value, 5G system update status to a 5U3 roaming not allowed.

3 . The method of claim 2 , further comprising, based on the 5GMM cause value:

resetting a service request attempt counter; and

entering a state of 5GMM-REGISTERED LIMITED-SERVICE.

4 . The method of claim 1 , further comprising:

discarding the first service reject message in case that the first service reject message including the 5GMM cause value is received without integrity protection.

5 . The method of claim 1 , wherein the 5GMM cause value is considered as an abnormal case in case that:

the 5GMM cause value is received by the UE that has not indicated support for cellular internet of things (CIoT) optimizations;

the 5GMM cause value is received by the UE over non-3 rd generation partnership project (3GPP) access; or

the 5GMM cause value is received from a cell belonging to a stand-alone non-public network (SNPN).

6 . The method of claim 1 , further comprising, based on the 5GMM cause value:

enabling evolved universal terrestrial radio access (E-UTRA) capability in case that the E-UTRA capability is disabled; and

disabling N1 mode capability for 3GPP access.

7 . A method performed by a network node, in a communication system, the method comprising:

receiving, from a user equipment (UE), a service request message;

in case that the network node receiving the service request message corresponds to an access and mobility management function (AMF):

identifying that redirection to an evolved packet core (EPC) is required for the UE, and

transmitting, to the UE, a first service reject message including a fifth generation (5G) mobility management (5GMM) cause value of #31, wherein the 5GMM cause value indicates that the redirection to EPC is required; and

in case that the network node receiving the service request message corresponds to a mobility management entity (MME):

identifying that redirection to a 5G core network (5GCN) is required for the UE, and

transmitting, to the UE, a second service reject message including an EPC mobility management (EMM) cause value of #31, wherein the EMM cause value indicates that the redirection to 5GCN is required.

8 . The method of claim 7 , wherein, in case that the first service reject message including the 5GMM cause value is transmitted to the UE without integrity protection, the first service reject message is discarded.

9 . The method of claim 7 , wherein the 5GMM cause value is considered as an abnormal case in case that:

the 5GMM cause value is transmitted to the UE that has not indicated support for cellular internet of things (CIoT) optimizations;

the 5GMM cause value is transmitted to the UE over non-3 rd generation partnership project (3GPP) access; or

the 5GMM cause value is transmitted by a cell belonging to a stand-alone non-public network (SNPN).

10 . A user equipment (UE) in a communication system, the UE comprising:

a transceiver; and

a processor coupled with the transceiver and configured to:

transmit a service request message;

in case that the service request message is transmitted to an access and mobility management function (AMF):

receive, from the AMF, a first service reject message including a fifth generation (5G) mobility management (5GMM) cause value of #31, and

identify that redirection to an evolved packet core (EPC) is required based on the 5GMM cause value; and

in case that the service request message is transmitted to a mobility management entity (MME):

receive, from the MME, a second service reject message including an EPC mobility management (EMM) cause value of #31, and

identify that redirection to a 5G core network (5GCN) is required based on the EMM cause value.

11 . The UE of claim 10 , wherein the processor is further configured to, based on the 5GMM cause value:

set a 5G system update status to a 5U3 roaming not allowed,

reset a service request attempt counter, and

enter a state of 5GMM-REGISTERED LIMITED-SERVICE.

12 . The UE of claim 10 , wherein the processor is further configured to discard the first service reject message in case that the first service reject message including the 5GMM cause value is received without integrity protection.

13 . The UE of claim 10 ,

wherein the processor is further configured to, based on the 5GMM cause value:

enable evolved universal terrestrial radio access (E-UTRA) capability in case that the E-UTRA capability is disabled, and

disable N1 mode capability for 3 rd generation partnership project (3GPP) access, and

wherein the 5GMM cause value is considered as an abnormal case in case that:

the 5GMM cause value is received by the UE that has not indicated support for cellular internet of things (CIoT) optimizations,

the 5GMM cause value is received by the UE over non-3GPP access, or

the 5GMM cause value is received from a cell belonging to a stand-alone non-public network (SNPN).

14 . A network node in a communication system, the network node comprising:

a transceiver; and

a processor coupled with the transceiver and configured to:

receive, from a user equipment (UE), a service request message;

in case that the network node receiving the service request message corresponds to an access and mobility management function (AMF):

identify that redirection to an evolved packet core (EPC) is required for the UE, and

transmit, to the UE, a first service reject message including a fifth generation (5G) mobility management (5GMM) cause value of #31, wherein the 5GMM cause value indicates that the redirection to EPC is required; and

in case that the network node receiving the service request message corresponds to a mobility management entity (MME):

identify that redirection to a 5G core network (5GCN) is required for the UE; and

transmit, to the UE, a second service reject message including an EPC mobility management (EMM) cause value of #31, wherein the EMM cause value indicates that the redirection to 5GCN is required.

15 . The network node of claim 14 ,

wherein, in case that the first service reject message including the 5GMM cause value is transmitted the UE without integrity protection, the first service reject message is discarded,

and

wherein the 5GMM cause value is considered as an abnormal case in case that:

the 5GMM cause value is transmitted to the UE that has not indicated support for cellular internet of things (CIoT) optimizations;

the 5GMM cause value is transmitted to the UE over non-3 rd generation partnership project (3GPP) access; or

the 5GMM cause value is transmitted by a cell belonging to a stand-alone non-public network (SNPN).

Assignments (1)

Priority Claims (2)

Continuity (1)

References Cited (49)