Telefonaktiebolaget Lm Ericsson (Publ)

Tomas Ekstedt

Jan Wichert

Johan Hokfelt

Magnus Karlsson

Joachim Ramkull

Jacob Lindquist

A mobile UE initiates a full search of all supported frequencies upon detecting a change in the Mobile Country Code (MCC) transmitted by a PLMN. The change in MCC indicates the user had crossed a political border, and the spectrum allocated for wireless communication may be different. In one embodiment, the mobile UE stores the current MCC. Upon obtaining an updated MCC, it is compared to the stored MCC. If the updated MCC is different from the stored MCC, the full frequency search is initiated. To prevent excessive searching, with concomitant power consumption, while traveling near a border, the UE waits a predetermined duration after an MCC-initiated full scan before conducting a subsequent full scan, even if the MCC changes within that duration.

PLMN frequency search triggered by country code change

By adapting its search procedures, a user equipment in a mobile communication system can shorten the time needed to find a cell or public land mobile network. If a first cell in a first radio access technology has been found, the equipment can exclude one or more frequencies from a search for cells in a second radio access technology. Thus, time and power are not wasted searching for cells in the second radio access technology that cannot be found.

Data sharing among radio access technologies

By evaluating a cell selection criterion S during scans for available public land mobile networks (PLMNs), a user equipment (UE) can avoid network service interruptions by not selecting PLMNs for which there exist no suitable cells. The cell selection criterion can be evaluated based on cell parameters either read during the PLMN selection procedure or locally stored before the PLMN selection procedure. It is possible to reduce the time required for PLMN scans and UE power consumption.

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Lund, Sweden

Tomas Ekstedt