Structure of a multi-carrier flexible spectrum wireless cell is determined from received synchronization or broadcast channels of detected individual carriers. The determined structure is used to select an intended carrier for initial access or cell reselection to the flexible spectrum wireless cell. The structure may have carriers compatible with an earlier version (LTE/Release 8) of a communication standard and with a later version (LTE-A/Release 9). The received synchronization channels can inform of: relative positions of the individual carriers in a spectrum band of the multi-carrier structure; relative timing alignments of the received synchronization channels; contents of the received synchronization channels; and/or layer 1 cell-carrier identifiers. The synchronization channels may have a different structure as between the earlier and later versions, and the different structure is used to select the carrier that is compatible with the user equipment making the selection.