downlink scheduling with a set of different subcompo- nents - CQI, Rank Indicator (RI), LI, precoding matrix indicator (PMI), SS/PBCH Block Resource indicator (SSBRI), CSI-RS resource indicator (CRI), and Reference Signal Received Power (RSRP) - as explained in more detail in the MIMO section. The UCI payload utilizes different encoding techniques depending on the payload size. A CRC of 6 bits is used if the UCI is 12-19 bits, and a CRC of 11 bits is used if the UCI is 20 bits or larger. For UCI sizes of 11 bits or less, no CRC is used. The following UCI channel coding techniques are used: - Simplex for 1 or 2 bits (HARQ-ACK or SR) - Reed-Muller for 3-11 bits (More complex HARQ-ACK) - Polar for > 11 bits (CSI feedback or very large HARQ-ACK) 5G provides a number of different ways to transmit UCI. There are five different PUCCH formats (Table 6.4) to carry, and in addition, UCI can be multiplexed within the PUSCH as simultaneous PUCCH and PUSCH transmissions are not supported. The PUCCH formats 0 and 1 with a small payload are designed for HARQ-ACK and SR transmission only; the short format (0) can be used if there is no issue with uplink coverage, and the long format (1) for coverage-limited scenarios. The short PUCCH can also be used in a TDD carrier's switching slot with lease, as shown in Figure 6.13. In addition, the short formats are more suitable for a gNB utilizing analog Rx beam 6 5G Physical Layer Table 6.4 Characteristics of the PUCCH formats. PUCCH Multiplexing format Waveform Modulation Duration Bandwidth capability DFT-S-OFDM Sequence selection 1-2 symbols 1 PRB 6 UEs with phase rotation 4-14 symbols 84 UEs > : 2 1-2 symbols 1-16 PRBs DFT-S-OFDM QPSK and Pi/2 4-14 symbols 1-16 PRBs 1 PRB 4 UEs forming, as it enables time-multiplexing several users' feedback without adding much to the feedback delay. The PUCCH formats 2-4 can be used for more complicated HARQ-ACK feedback, where several downlink slots' HARQ-ACKs are mapped to one uplink slot in a TDD configuration. The HARQ-ACK feedback size further i