Method and apparatus for releasing connection with local GW when UE moves out of the residential/enterprise network coverage

A mobility management node for use in a core network communicatively connected with a first radio access network (RAN) comprising a first network element, and a second RAN comprising a second network element, the mobility management node comprising:

• at least one processor configured to:
• receive a first Non Access Stratum (NAS) message via the second network element from a User Equipment (UE), wherein the UE has, with the first network element, one or more packet data network (PDN) connections;
• detect that the UE is connected to the second network element that is different from the first network element that has a first identifying characteristic, wherein the detecting comprises determining that the first NAS message is received with a second identifying characteristic of the second network element different from the first identifying characteristic associated with the one or more PDN connections, the first identifying characteristic stored at the mobility management node;
• and
• in response to the determining that the first NAS message is received with the second identifying characteristic of the second network element different from the first identifying characteristic:
• determine that the UE has only one or more selected IP traffic offload (SIPTO) PDN connections;
• in response to determining that the UE has only one or more SIPTO PDN connections, send a second NAS message including a cause code with a value that represents “No EPS Bearer Context Activated”.

A non-transitory storage medium storing instructions that upon execution cause a mobility management node in a core network communicatively connected with a first radio access network (RAN) comprising a first network element and a second RAN comprising a second network element, to:

• receive a first Non Access Stratum (NAS) message via the second network element from a User Equipment (UE), wherein the UE has, with the first network element, one or more packet data network (PDN) connections;
• detect that the UE is connected to the second network element that is different from the first network element that has a first identifying characteristic, wherein the detecting comprises determining that the first NAS message is received with a second identifying characteristic of the second network element different from the first identifying characteristic associated with the one or more PDN connections, the first identifying characteristic stored at the mobility management node;
• and
• in response to the determining that the first NAS message is received with the second identifying characteristic of the second network element different from the first identifying characteristic:
• determine that the UE has only one or more selected IP traffic offload (SIPTO) PDN connections;
• in response to determining that the UE has only one or more SIPTO PDN connections, send a second NAS message including a cause code with a value that represents “No EPS Bearer Context Activated”.