ncy of the system is evaluated by dividing the MAC layer spectral efficiency by the physical layer spectral efficiency. The average cell spectral efficiency is defined as: (12-8) where Raggregate denotes the aggregate cell throughput and BW, effective is the effective channel band- width. The effective channel bandwidth is defined as BW, effective transmission where BWtransmission denotes the channel bandwidth, and aDL-UL is the downlink/uplink ratio in the TDD systems. Note that for FDD systems ADL-UL = 1, and for TDD systems with a DL: UL ratio of 2:1 aDL-UL = 2/3 for DL, and 1/3 for UL, respectively. The CDF of SINR is defined as the cumulative distribution function for the signal-to-interference and noise ratio as measured by the BS (or the MS) for each MS (or the BS) on the uplink or downlink, respectively. This metric would allow comparison between different reuse scenarios, network loading conditions, smart antenna algorithms, resource allocation, power control schemes, etc. CHAPTER 12 Performance of IEEE 802. 16m and 3GPP LTE-Advanced 12.2 CALCULATION OF STATIC AND DYNAMIC OVERHEAD The calculation and analysis of the signaling and control channels' overhead as well as the physical layer overhead associated with synchronization and broadcast channels, guard time and guard bands, reference signals, and that of the cyclic prefix are important in determining the actual performance of a cellular system. In general, the overhead channels are essential for proper oper- ation of a cellular system and statically (independent of the number of the users in the cell) or dynamically (depending on the number of the users in the cell) consume some radio resources and make them permanently or temporarily unavailable for data transmission. There are two types of overhead channels: static and dynamic. A static overhead channel requires fixed base station power, time slot, and/or bandwidth. On the other hand, a dynamic overhead channel requires base station power, time, and/or bandwidth which dynamically change over time as