Non-access stratum signalling to indicate use of new or existing NAS signalling connection for connection re-establishment.

摘要

A non-access stratum (NAS) signal is sent from a mobile radio communications network (e.g. UMTS or LTE) device 302 to a mobile radio communications device 300 after a failed attempt by the mobile device to access the network via the network device 304 . The NAS signal indicates (preferably using a flag which my comprise a bit) which one of: (i) an existing NAS signalling connection; or (ii) a new NAS signalling connection, the mobile device should employ to attempt re-establishment of connection with the network device 308. The signal indicating (i) may be the inverse of the signal indicating (ii). Having indicated (i) the network device may maintain the existing NAS signalling connection. Having indicated (ii) the network device may release the NAS signalling connection. Having received an indication of which option should be used to re-establish the connection the mobile device may transmit a request for re-establishment via the indicated means 312.