E 1588-2002 standard that allows precise synchronization of networks (e.g., Ethernet). Accuracy within the nanosecond range can be achieved with this protocol when using hardware generated timestamps [14]. 4.5 Operational states of femto base stations During normal operation and as part of handover, the MS typically measures the received RF signal strength from the serving and the neighboring base stations and selects the most viable candidate base stations as target for handover. The measurements are usually conducted on the synchronization sequences that are unique to each base station and further carry the Cell_ID. The type of the cell may also be communicated via the synchronization sequences if a hierarchical synchronization scheme is utilized. Since the number of bits that can be carried through the synchronization sequences are limited, additional information on the cell type and other configuration restrictions are broadcast as part of system configuration information. In the IEEE 802.16m, there are two steps of downlink synchronization. The downlink synchro- nization is achieved by successful acquisition of the primary advanced preamble. The primary advanced preamble carries information about system bandwidth (e.g., 5, 10, 20 MHz) and multi-carrier configuration (i.e., fully configured or partially configured RF carrier). Once the primary advanced preamble is detected, the MS proceeds to acquisition of the secondary advanced preambles. The secondary advanced preamble carries a set of 768 distinct Cell_IDs that have been partitioned into number of subsets where each subset corresponds to a certain type of base station (e.g., closed/open subscriber group femto base stations or macro base stations). Normally the MS has to acquire the synchronization sequences and to detect the Cell_ID followed by detection of the broadcast channel to complete the cell selection. If the MS realizes that the cell is a non-accessible femto BS or access node, it has to restart the cell search and to select another cell. This ef