A new RRC Connected (mobility) state is described in which a UE utilizes a temporary identifier to monitor a downlink control channel in accordance with a discontinuous reception cycle; and maintains the new connected state, the discontinuous reception cycle and the temporary identifier while the UE re-selects to a second/serving access node which lies within a same designated reselection area as a first/source access node. In various specific embodiments, the DRX cycle is maintained but re-aligned with a system frame number of the second access node; the temporary identifier is a CRNTI and the designated re-selection area is defined by all contiguous cells in which respective access nodes broadcast the CRNTI in system information; the UE re-selects to the second access node in the absence of control signaling; and the UE enters the new connected mobility state automatically upon expiry of a time alignment timer or upon explicit network signaling while in a different connected state.

This invention allows Cooperating mobiles (ground vehicles, aircraft) to be located and identified by Multilateration and Automatic Dependent Surveillance - Broadcast (ADS -B) techniques using the frequency band and the format of the Secondary Surveillance Radar (SSR) signals in high traffic situations, such as those of large airports. Standard messages, transmitted by the mobile on the downlink channel, i.e. to a set of fixed receiving stations, and including the identification code, permit the location of the mobile by multiple time measurements (Multilateration) from a subset of the set of fixed receiving stations; when the message contains the position (GPS and, later, Galileo datum) the mobile may be located with the ADS-B when in view even of a few stations or of a single station. In order to overcome the problem that arises with high traffic, i.e. the superimposition of signals, called garbling, the present invention uses (a) a variable carrier frequency in the downlink channel (b) a time division scheme for the transmission from different mobiles . In this way, the system becomes suitable to the discrimination of overlapped signal; this is obtained by frequency analysis and, in the cases of high traffic in the downlink channel, by super resolution techniques. Moreover, the downlink transmission capacity increases with respect to the present state of the art respecting the bandwidth limits as defined by the international regulations. The present invention includes a signal generation and transmission system with selection of the carrier frequency (called frequency agility) and with selection of the transmission time for each mobile (called time agility or time division multiple access), as well as signal discrimination means in the receiving fixed station.