#No suitable cells in tracking area registration

On each carrier frequency, the UE need only search for the strongest cell. The UE shall scan all RF channels in the E-UTRA bands according to its capabilities to find a suitable cell. This procedure requires no prior knowledge of which RF channels are E-UTRA carriers. If no suitable cell is found on any frequency or RAT the UE should attempt to find an acceptable cell.Ĭell Selection Process Initial Cell Selection The UE should attempt to find a suitable cell in the manner described for stored information or initial cell selection above. On transition from RRC_CONNECTED to RRC_IDLE, a UE should camp on the last cell for which it was in RRC_CONNECTED or a cell/any cell of set of cells or frequency be assigned by RRC in the state transition message. An acceptable cell is one for which the measured cell attributes satisfy the cell selection criteria and the cell is not barred.A suitable cell is one for which the measured cell attributes satisfy the cell selection criteria the cell PLMN is the selected PLMN, registered or an equivalent PLMN the cell is not barred or reserved and the cell is not part of a tracking area which is in the list of “forbidden tracking areas for roaming”.When a suitable cell is found or if only an acceptable cell is found it camps on that cell and commence the cell reselection procedure The UE seeks to identify a suitable cell if it is not able to identify a suitable cell it seeks to identify an acceptable cell.The UE may search each carrier in turn (“initial cell selection”) or make use of stored information to shorten the search (“stored information cell selection”).

It reads cell system information broadcast to identify its PLMN(s)

The UE searches the E-UTRA frequency bands and for each carrier frequency identifies the strongest cell.

The UE shall select a suitable cell based on idle mode measurements and cell selection criteria.

#No suitable cells in tracking area registration

The NAS can control the RAT(s) in which the cell selection should be performed, for instance by indicating RAT(s) associated with the selected PLMN, and by maintaining a list of forbidden registration area(s) and a list of equivalent PLMNs. The UE NAS layer identifies a selected PLMN and equivalent PLMNs.Cell selection is required on transition from EMM_DETACHED to EMM-REGISTERED and from ECM-IDLE or ECM-CONNECTED.

The principles of PLMN selection in E-UTRA are based on the 3GPP PLMN selection principles.