 = 49 MRMAC/s preamble detection/peak search: 1 carrier X 8 received antennas X 6 PRACH occasions X 1 PRACH slot per subframe X 256 IFFT size X 2 operations (noise averaging and max search) X 2000 slot/second = 49 MROPS/s Sounding Reference Signal (SRS) is assumed to follow a regular frequency-domain channel estimation given the narrowband allocation. Time-domain channel estimation would provide performance improvement for a wideband configuration at the expense of larger complexity. Symbol FFT is assumed to be performed in RRH as explained before. Rest of the processing is assumed to be done in DU following breakdown, leading to a total of MROPS. It is also assumed that SRS is processed within a slot, but larger latency might be acceptable leading to lower average complexity. 1 carrier X 48 RB/comb X 4 combs X 12 cyclic shifts X 4 symbol X 2000 slot/ second = 18 MCMAC/s or 74 MRMAC/s 316 Open Radio Access Network (O-RAN) Systems Architecture and Design Aggregate compute cost (excluding PRACH/SRS, who are either implemented in the radio unit (RU) or in background tasks that are not considered performance critical) is 21GOPS/second. Now, this is a strictly theoretical number that will not be achieved for two reasons: 1. Even when implemented by means of highly optimized software kernels, general-purpose processors rarely achieve even half of the theoretical performance due to overheads associated with load/store operations, data conversion, cache misses, dependencies in the processor pipeline, and other inefficiencies. Based on benchmarking, we see 50% effective utilization of an SIMD engine to be a realistic maximum, even when operating from warm cache memory and an otherwise optimized environment. 2. The environment described above does not consider cache misses, overheads for data conversion and similar operations, and so on. We assume another factor of 2 as a first approximation to account for the delta between low-level kernel performance and system performance when multiple kernels are integrated together to