e sequences, in order to enable early distinction of femto BS from the macro BS which helps the MS to avoid unnecessary network entry and handovers to/from a femto BS. A large number of femto base stations may be configured within the same CSG, which has the same group of authorized mobile stations. A common identifier may be assigned to all CSG femto base stations which are part of CHAPTER 4 IEEE 802. 16m System Operation and State Diagrams the same CSG. An MS may use this identifier for accessibility checking for the CSG femto base stations. A common identifier known as CSG ID is used to identify the base stations belonging to the same CSG. The CSG ID is unique within the same operator ID. The CSG ID, as a part of the BS ID, may be derived from the full 48-bit BS ID, or may be provided to the CSG femto BS during initial network entry in the registration response, or may be pre-provisioned by the network. The mobile station's CSG White List (i.e., a local table in the MS containing the identities of all the CSG femto base stations to which the MS is subscribed and is authorized to access)xiii may contain the identifiers of allowable femto base stations. During network entry or re-entry, the MS begins scanning of the neighbor base stations through RF measurements. The detection of the Cell_ID helps categorizing the BS type and, depending on the preference of the MS, a macro or femto candidate is selected. Failure in any stage of the cell search and cell selection will result in repeating the scanning and downlink synchronization steps. The Operator- ID (i.e., the 24 most significant bits of BS-ID) and the least significant bits of the BS-ID will help the MS to determine whether it is authorized to access to the target BS. The BS-ID in Figure 4-23 refers to the least significant bits of the 48-bit BS-ID parameter. The MS must be subscribed to the operator identified by the Operator-ID and must have the BS-ID in its White List The algorithm illustrated in Figure 4-23 provides the procedures which the MS follows to 