r The physical PUCCH channel is defined by a short (Short PUCCH) or long (Long PUCCH) structure. The Short PUCCH physical channel is transmitted in the time domain on the last symbol or the last two symbols. The physical DM-RS signal and UCI information are frequency multiplexed (FDM) with a density of 1/2, 1/4 or 1/6. The Long PUCCH physical channel is transmitted in the frequency domain on one or more PRBs and in the time domain on a set of symbols in a slot. The physical DM-RS signal and UCI information are frequency multiplexed (TDM). PUCCH With frequency hopping PUCCH PUCCH Without frequency hopping Figure 4.20. The DM-RS signal mapping associated with the short and long PUCCH channels 4.6.1.4. The physical PT-RS signal The PT-RS signal is optional. The mobile is informed of the presence of the PT-RS signal during radio link reconfiguration (RRC signaling), via the timedensity parameter carried by the PTRS-UplinkConfig. The physical PT-RS is a copy of the DM-RS associated with the PUSCH channel; it must not be mapped to the resource elements used for the physical DM-RS signals. In the time domain, the PT-RS is repeated every L symbols, taking the DM-RS as reference. In the frequency domain, the PT-RS is transmitted on the same subcarriers as the physical DM-RS (type 1 or type 2 configuration). NG-RAN and 5G-NR 4.6.2. The physical channel 4.6.2.1. The random physical PRACH channel The physical PRACH (Physical Random Access Channel) channel contains a preamble sent by the mobile when it has to perform a random access. In the time domain, the signal must be transmitted during a TPRACH window. TPRACH window is a succession of time slots, during which the mobile has NRA opportunities for the transmission of the physical PRACH. The duration of the PRACH sent by the mobile is defined by the value NRA and corresponds to the number of repetitions of the sequence. In the time domain, the value of the transmission symbol of the physical PRACH channel transmitted by the mobile is calculated as follows: is the position o