3300-4200 10-100 3300-3800 10-100 4400-5000 40-100 1710-1785 880-915 832-862 703-748 1920-1980 1710-1780 2496-2690 10-100 Table 4.1. Frequency band FR1 5G-NR 5G-NR - FR2 operational bands Frequency [GHz] Bandwidth [MHz] Duplexing method 26.5-29,5 50-400 24.25-27.5 50-400 39.5-43.5 50-400 37-40 50-400 27.5-28.35 50-400 Table 4.2. Frequency band FR2 5G-NR NG-RAN and 5G-NR Duplexing defines how to share the communication channel between the DL (downlink) and the UL (Uplink) transmission. There are three main duplexing modes (Figure 4.2) and a hybrid mode: - FDD (Frequency Division Duplexing); - TDD (Time Division Duplexing); - FD (Full Duplex) spatial duplexing; - SUL (Supplementary Uplink) mode. Guard time Guard band Sub-frame Sub-frame Guard time Sub-frame Sub-frame Figure 4.2. 5G-NR multiplexing techniques FDD multiplexing requires two frequency paired bands, one band for the downlink transmission and another for the uplink transmission. The downlink and uplink bands are separated by a frequency guard band. The frequency band used by the mobile for the uplink channel is controlled by the base station, and the control information is transmitted to the mobile on the paired downlink band. For TDD multiplexing, the two directions of transmission share the same frequency band, temporally. TDD multiplexing can increase the throughput of the downlink at the expense of the uplink by allocating more time for the downlink transmission. TDD is better than FDD in exploiting the massive-MIMO technique. For FD multiplexing, the two directions of transmission occur simultaneously in the same band, exploiting the spatial diversity of the radiating elements: one part of the radiating elements is configured for transmission and the other part for reception. 5G-NR Radio Interface - The Physical Layer The 5G-NR radio interface offers the SUL transmission mode: an additional frequency band is introduced, just for the uplink. Unlike FDD multiplexing, the SUL uplink is paired with any downlink band. This mode improves the coverage area