User equipment registration method for network slice selection and network controller and network communication system using the same

A network controller, comprising:

• a transceiver;
• and
• a processor, coupled to the transceiver, and configured to:
• receive, by an access and mobility management function, a registration request of a user equipment via the transceiver, wherein the registration request comprises network slice selection assistance information (NSSAI);
• in response to receiving the registration request, determine by the access and mobility management function, whether the access and mobility management function has a capability for serving the user equipment according to the NSSAI so as to transmit a first network function discovery request including the NSSAI or a second network function discovery request for searching a target access and mobility management function;
• and
• select, by the access and mobility management function, a network function for serving the user equipment according to a network function discovery response to perform a registration setting operation with the selected network function after the access and mobility management function receives the network function discovery response corresponding to the first network function discovery request, or transmit an interface connection release message to an access node after the access and mobility management function receives another network function discovery response corresponding to the second network function discovery request.

A network communication system, comprising:

• a first network controller;
• and
• a second network controller, connected to the first network controller,
• wherein the first network controller receives, by an access and mobility management function, a registration request of a user equipment, wherein the registration request comprises network slice selection assistance information (NSSAI);
• in response to receiving the registration request, the first network controller determines, by the access and mobility management function, whether the access and mobility management function has a capability for serving the user equipment according to the NSSAI, so as to transmit a first network function discovery request including the NSSAI;
• the second network controller receives a first network function discovery request including the NSSAI, and determines a candidate network function associated with a candidate network slice according to the NSSAI;
• the second network controller provides the candidate network function to the first network controller by transmitting a network function discovery response corresponding to the first network function discovery request;
• and
• the first network controller selects a network function for serving the user equipment according to the network function discovery response to perform a registration setting operation with the selected network function after the network function discovery response corresponding to the first network function discovery request is received by the first network function controller.