Method and apparatus for providing network switching service in 5G communication system

1 . A method of a network apparatus for providing a network switching service for enabling a user equipment to switch a communication network between a public network and a private network by communicating with a subscriber apparatus, where the subscriber apparatus stores subscribed Network Slice Selection Assistance Information (NSSAI) of the user equipment and a network selection discriminator (NSD) at a subscriber profile, the network selection discriminator (NSD) indicates a network selected by the user equipment, the method comprising:

receiving a registration request from the user equipment and transmitting a slice selection subscription data request to the subscriber apparatus;

receiving the subscribed NSSAI from the subscriber apparatus,;

transmitting a registration response including allowed S-NSSAI based on the received subscribed S-NSSAI; and

receiving a session establishment request including the allowed S-NSSAI from the user equipment and creating a session to one of the public network and the private network according to the allowed S-NSSAI included in the session establishment request,

wherein:

the subscriber apparatus stores S-NSSAI for a public network and S-NSSAI for a private network as the subscribed S-NSSAI of the user equipment;

the receiving subscribed S-NSSAI comprises receiving S-NSSAI for the public network from the subscriber apparatus in an event that the network selection discriminator (NSD) indicates the public network; and

the creating a session comprises generating a session to the public network.

2 . The method of claim 1 , wherein:

the subscriber apparatus stores S-NSSAI for a public network and S-NSSAI for a private network as the subscribed S-NSSAI of the user equipment;

the receiving subscribed S-NSSAI comprises receiving S-NSSAI for the private network from the subscriber apparatus in an event that the network selection discriminator indicates the private network; and

the creating a session comprises generating a session to the private network.

3 . The method of claim 1 , wherein the S-NSSAI for the public network and the S-NSSAI for the private network is identified by a slice service type (SST).

4 . The method of claim 1 , wherein the network selection discriminator (NSD) of the subscriber apparatus is changed to one of i) a discriminator for a public network and ii) a discriminator for a private network according to a trigger signal from the user equipment.

5 . A method of a network apparatus for providing a network switching service to user equipment for switching a communication network between a private network and a public network, the method comprising;

transmitting a slice selection subscription data request to a subscription apparatus upon receiving of a registration request from the user equipment;

in response to the slice selection subscription data request, receiving subscribed Network Slice Selection Assistance Information (NSSAI) from the subscriber apparatus and default NSSAI; and

including allowed NSSAI in a registration response and transmitting the registration response to the user equipment,

wherein the default NSSAI is determined based on a network selection discriminator (NSD) stored in a subscriber profile of the user equipment, and the network selection discriminator (NSD) is set to have one of values 0 and 1, each indicates the public network and the private network, respectively.

6 . The method of claim 5 , wherein the network selection discriminator is changed from 0 to 1 or from 1 to 0 upon receiving a trigger signal for switching a communication network from the user equipment.

7 . The method of claim 5 , wherein the allowed NSSAI has at least one value indicating at least one allowed network to access which is determined based on values included in the received subscribed NSSAI.

8 . The method of claim 5 , wherein the allowed NSSAI included in the registration response has two values one indicating the public network and the other indicating the private network.

9 . The method of claim 8 , wherein the selecting comprises:

determining whether the subscribed NSSAI has a Null value;

identifying a value included in the default NSSAI which is received in response to the slice selection subscription data request; and

selecting one of the public network and the private network based on the identified value of the default NSSAI.

10 . The method of claim 5 , further comprising:

receiving a session establishment request including subscribed NSSAI from the user equipment;

selecting one of the public network and the private network based on values included in the allowed S-NSSAI in the session establishment request; and

creating a session to the selected one.

11 . The method of claim 8 , wherein the receiving subscribed NSSAI from the subscriber apparatus and default NSSAI comprises:

receiving Nudm_5DM_Get_Response from the subscription apparatus, including subscribed NSSAI that has values one indicating the public network and the other indicating the private network.

12 . A network apparatus for providing a network switching service to user equipment for switching a communication network between a private network and a public network, the network apparatus comprising;

a memory configured to store data including subscribed network slice selection assistance information (NSSAI) and default NSSAI;

a communication circuit configured to communicate with other entities including a subscription apparatus, a service server, and the user equipment through a communication network;

a processing circuit configured to perform at least one of: transmitting a slice selection subscription data request to a subscription apparatus upon receiving of a registration request from the user equipment; in response to the slice selection subscription data request, receiving subscribed Network Slice Selection Assistance Information (NSSAI) from the subscriber apparatus and default NSSAI; and including allowed NSSAI in a registration response and transmitting the registration response to the user equipment,

wherein the default NSSAI is determined based on a network selection discriminator (NSD) stored in a subscriber profile of the user equipment, and the network selection discriminator (NSD) is set to have one of values 0 and 1 , each indicates the public network and the private network, respectively.

13 . The network apparatus of claim 12 , wherein the network selection discriminator is changed from 0 to 1 or from 1 to 0 upon receiving a trigger signal for switching a communication network from the user equipment.

14 . The network apparatus of claim 12 , wherein the allowed NSSAI has at least one value indicating at least one allowed network to access which is determined based on values included in the received subscribed NSSAI.

15 . The network apparatus of claim 12 , wherein the allowed NSSAI included in the registration response has two values one indicating the public network and the other indicating the private network.

16 . The network apparatus of claim 12 , wherein the processing circuit is configured to further perform: receiving a session establishment request including subscribed NSSAI from the user equipment; selecting one of the public network and the private network based on values included in the allowed S-NSSAI in the session establishment request; and creating a session to the selected one.

17 . The network apparatus of claim 16 , wherein the processing circuit is configured to further perform: determining whether the subscribed NSSAI has a Null value;

identifying a value included in the default NSSAI which is received in response to the slice selection subscription data request; and selecting one of the public network and the private network based on the identified value of the default NSSAI.