s information remains unchanged over a long period of time, some parts may change more frequently) broadcast using a robust and reliable transmission format to ensure the information can be correctly detected by all mobile stations in the coverage area of a base station. The correct and timely detection of the system information is essential for successful network entry/re-entry and handover. The secondary superframe header content is divided into three sub-packets where sub-packets carry essential information for various system processes, such as initial network entry, network re-entry, Idle-State operation, etc., according to their respective timing sensitivity. Once the system parameters are successfully acquired, the cell selection decision can be made by taking certain considerations into account. For example, the mobile station may have a preference in selecting a specific type of base station (e.g., a femto-cell in an indoor environment), even though other types of the base station may be available or the MS may not be authorized to access a group of base stations despite the fact that their received RF signal strength might be good. Also, the IEEE 802.16m standard defines a system parameter called Cell Bar bit that is carried in the secondary superframe header. If Cell Bar bit is set to 1, the cell does not allow any new initial entry due to excess load in the cell [2]. 4.1.2 Access State Once the mobile station selects a suitable cell, it proceeds to the Access State to complete the network entry/re-entry procedures. Figure 4-4 shows the Access State procedures. The first step is to perform the initial ranging and uplink synchronization with the base station. The initial ranging is the process of acquiring the correct timing-offset, frequency-offset, and transmit-power adjustments SO that the MS uplink transmissions are aligned with the BS uplink frame. The physical layer processing delays are relatively constant and the variations are accounted for in the guard time. The initial contention-based ranging