Interconnections between the core networks

A method of establishing a connection via a core network by a mobile terminal, the method comprising:

• receiving in a first cell an identifier assigned by a node in a first core network, the identifier comprising an identifier of a node or group of nodes in the first core network,
• selecting a second cell,
• determining whether service via a core network of the first type is available from the second cell,
• establishing a connection via the second cell by transmitting an access signal based on at least a portion of the identifier,
• when service via a core network of the first type is available from the second cell, transmitting with the access signal a first indication, the first indication indicating whether or not the identifier was received from a core network of the first type, and
• when service via a core network of the first type is not available from the second cell, refraining from transmitting the second indication in the message.

A mobile terminal for use in a wireless communication system, the wireless communications system comprising a first core network of a first type and a second core network of a second type, the mobile terminal comprising controller circuitry, transmitter circuitry and receiver circuitry configured to operate together such that the terminal device is operable:

• to receive by the mobile terminal in a first cell an identifier assigned by a node in the first core network of a first type, the identifier comprising an identifier of the node or a group of nodes in the first core network,
• to select a second cell, the second cell permitting service via the second core network of the second type,
• to determine whether service via a core network of the first type is available from the second cell,
• to establish a connection via the second cell by transmitting a message including a first indication, the first indication based on at least a portion of the identifier, and
• when service via a core network of the first type is not available from the second cell, to transmit in the message a second indication, the second indication indicating that the identifier was received from a core network different from the second type.

A mobile terminal for use in a wireless communication system, the wireless communications system comprising a first core network of a first type and a second core network of a second type, the mobile terminal comprising controller circuitry, transmitter circuitry and receiver circuitry configured to operate together such that the terminal device is operable:

• to receive in a first cell an identifier assigned by a node in the first core network, the identifier comprising an identifier of a node or group of nodes in the first core network,
• to select a second cell,
• to determine whether service via a core network of the first type is available from the second cell,
• to establish a connection via the second cell by transmitting an access signal based on at least a portion of the identifier,
• when service via a core network of the first type is available from the second cell, to transmit with the access signal a first indication, the first indication indicating whether or not the identifier was received from a core network of the first type, and
• when service via a core network of the first type is not available from the second cell, to refrain from transmitting the second indication in the message.