Method and apparatus for supporting user's mobility over a local area data network

A system for supporting a local area data network (LADN), comprising:

• a session management function (SMF) network element, configured to:
• determine whether a first condition is met, wherein the first condition comprises:
• a first location of a user equipment (UE) is outside a service area (SA) of a LADN;
• in response to determining that the first condition is met,
• determine a first policy from a plurality of policies based on a LADN name and user information;
• notify an user plane function (UPF) network element to enable a timer;
• stop data transmission of an LADN packet data unit (PDU) session of the LADN based on the first policy;
• and
• maintain a resource of the LADN PDU session based on the first policy before the timer expires;
• and
• the user plane function (UPF) network element, configured to:
• receive downlink data after the timer expires;
• and
• in response to receiving the downlink data after the timer expires, send a downlink data notification to the SMF network element, and
• wherein the SMF network element is further configured to, when the timer expires and in response to receiving the downlink data notification from the UPF network element, trigger the LADN PDU session to enter an activation state,
• wherein a duration of the timer is less than a duration of periodic location update received from an access and mobility management function (AMF) network element.

An apparatus for supporting a local area data network (LADN), comprising:

• at least one processor coupled with one or more memories that store programming instructions for execution by the at least one processor to:
• determine whether a first condition is met, wherein the first condition comprises:
• a first location of a user equipment (UE) is outside a service area (SA) of a LADN;
• in response to determining that the first condition is met,
• determine a first policy from a plurality of policies based on a LADN name and user information;
• notify an user plane function (UPF) network element to enable a timer;
• stop data transmission of an LADN packet data unit (PDU) session of the LADN based on the first policy, wherein stopping the data transmission of the LADN PDU session comprises notifying the user plane function (UPF) network element to buffer or discard downlink data received before the timer expires;
• maintain a resource of the LADN PDU session based on the first policy before the timer expires;
• when the timer expires and in response to receiving a downlink data notification from the UPF network element, trigger the LADN PDU session to enter an activation state,
• wherein a duration of the timer is less than a duration of periodic location update received from an access and mobility management function (AMF) network element.