guration parameters; (3) classifying the system configuration parameters based on their timing sensitivity and necessity for network entry, handover, paging, etc., thus transmitting system information sub-packets with different periodicity; and (4) increasing the number of unique Cell_IDs from 114 to 768 and changing the synchronization scheme from non-hierarchical to hierarchical [3]. Figure 4-3 illustrates the initialization procedures in IEEE 802.16m. The cell search starts with scanning for the available downlink RF channels. The DL synchronization 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 preamble. The secondary advanced preamble carries a set of "In a non-hierarchical synchronization (i.e., a single step synchronization scheme), the preamble consists of one or more cell-specific waveforms and is used for time synchronization and frame alignment. In a hierarchical synchronization (i.e., a multi-step synchronization scheme), two or more unique set of signals are used for time synchronization and detection of the Cell_ID, and other relevant information for the cell or network. CHAPTER 4 IEEE 802. 16m System Operation and State Diagrams 768 distinct Cell_IDs that have been partitioned into a number of subsets where each subset corre- sponds to a certain type of base station (e.g., closed/open subscriber group femto base stations or macro base stations). Upon successful acquisition of system timing and cell identification, the MS attempts to detect and decode the system configuration information. This information is carried via the superframe headers. The superframe headers, comprising primary and secondary superframe headers, are control elements that are periodically (while a large part of thi