ormat 2, wherein more than two UCI bits can be transmitted over 4-14 OFDM symbols, where there can be multiple resource blocks on each symbol. As a result, it is the PUCCH format with the largest pay- load capacity. The OFDM symbols are used for carrying the UCI and the PUCCH DM-RS. The control information is encoded using Reed-Muller codes for payload sizes less than 11 bits and polar codes for larger payloads and then scrambled and modulated. The scram- bling sequence is based on the UE identity (C-RNTI) together with the physical-layer cell identity (or a configurable virtual cell identity), ensuring interference randomization across cells and devices that use the same set of time-frequency resources. Prior to channel coding stage, a CRC is attached to the control information for large payloads. The encoded bits are QPSK modulated; however, there is an option to use 2-BPSK modulation to lower the cubic metric at the expense of some loss in link performance. The complex-valued modula- tion symbols are distributed among the OFDM symbols and DFT precoding is performed to reduce the cubic metric and improve the power amplifier efficiency. The structure of PUCCH format 4 is similar to that of PUCCH format 3 with the possibility to code-multiplex multiple devices over the same resources using one resource block in the frequency domain. Each OFDM symbol carries 12/NSF unique modulation symbols. Prior to DFT-precoding, each modulation symbol is block-spread with an orthogonal sequence of length NSF. The spreading factors of length two and four are supported, implying that the multiplexing capacity would be two or four devices on the same set of resource blocks. As shown in Fig. 4.81, frequency hopping can be configured for PUCCH format 3/4 to exploit frequency diversity; however, these PUCCH formats can operate without frequency hopping. The location of the reference signal symbols depends on the frequency hopping and the length New Radio Access Physical Layer Aspects (Part 2) 615 UCI bits Channel coding Scrambling se