on at the eNB, and the L1/L2 control signaling transmitted on configurable amounts of resource blocks, as well as L2 control overhead due to random access, uplink time-alignment control, power headroom reports, and buffer-status reports. The L2 overhead associated with the PDU headers (MAC/ RLC/PDCP) is further taken into consideration in the overall overhead calculation. The amount of overhead due to DM-RS is approximately 14%, corresponding to one DFTS-OFDM symbol in each slot. The relative overhead is estimated independent of the rank of the transmission. The amount of SRS overhead depends on the sounding signal transmission interval and the bandwidth of the sounding signal. Using a 10 ms SRS transmission interval and full-band SRS, the relative overhead is approximately 0.7%. The amount of uplink resources reserved for random access depends on the PRACH configuration, e.g., a typical case with PRACH format 0 is six resource blocks per radio frame, resulting in a relative overhead of 0.6%, 1.2%, and 2.4% for a channel bandwidth of 20, 10, and 5 MHz respectively. CHAPTER 12 Performance of IEEE 802. 16m and 3GPP LTE-Advanced The relative overhead due to uplink timing-alignment control depends on the configuration and the number of active UEs within a cell. The absolute overhead is typically less than 32 bits/s per UE. The amount of overhead for buffer status reports depends on the configuration; assuming a continuous data and a reporting interval of 10 to 20 ms, the absolute overhead is 0.8-3.2 kbps. The amount of overhead due to PDU headers depends on the data packet size and is approximately 2.7%, 0.51%, and 0.32% for L1 data rates of 1, 10, and 100 Mbps, respectively. The above overhead calculations are based on normal CP length. In the case of MBSFN subframes in the TDD mode, all the subframes are assumed to be of the MBSFN type in the overhead estimation. The overall overhead depends on the fraction of MBSFN subframes. In self-evaluation results, a fraction of 0% and 33% has been assumed for a DL:UL ratio o