 not be detected within the CB. Probability of 4-bits in error within a CB can be estimated assuming Binomial distribution and using probability mass function: Probability of 4-bits in error = nchoosek(CB_size, 4) X (BER)^4 X (1-BER)^ (CB_size - 4) = 2.1 X 10-10. A CB CRC may not detect this error combination, this is the probability that the CB may "falsely" pass the CB. The probability that the TB has at least 1 CB with 4 bits in error = (approx.) 2.1 X 10-10 num_CBs n_TB = 1.15 X 10-8. If TB CRC was checked, then the above scenario could "likely" be detected. In the absence of TB CRC validation, 1.15 X 10 is the probability that a "bad" TB could be passed up to L2 as a "good" TB. As such, this probability is low enough without considering the Hamming Weights, which will make it even smaller. All 4-bit error combinations are not undetected by CB CRC, only some of them. Also, the BER was chosen conservatively in the above example. 126 Open Radio Access Network (O-RAN) Systems Architecture and Design Transmit operation In the transmit operation, the Transport Block is typically re-encoded (from scratch) for every transmission and/or retransmission. This means that there is no requirement for main- taining a HARQ Physical Layer context in the modem. Each TB is retrieved (typically from the MAC layer entity) new for each transmission and retransmission. Note that this does not impose any bandwidth penalty. The system is designed for 100% successful transmit operation and the associated memory or I/O bandwidth(s). Retransmissions take away time/frequency resources that would otherwise be allocated to "new" transmissions. Overall, there is no I/O bandwidth impact. HARQ process count dimensioning We discussed HARQ process definitions previously, including discussion on synchronous and asynchronous HARQ options. Even with asynchronous HARQ though, the maximum throughput that the communication path between base station and client can achieve is limited by the num- ber of active HARQ processes, given that a single HARQ p