dition of the 3.5 and 4.5 GHz NR bands, but also due to the potential addition of the 6 GHz unlicensed band extension of the current 5.15-5.925 GHz band (5.925-7.125 GHz in the United States and 5.925-6.425 GHz in Europe). This 25% increase in potential concurrent RF paths also results is a 15% increase in required band filters. Although Table 12.11 already provides a good picture of the size and routing com- plexity of the RF portion of a 5G phone, Figure 12.22 gives a better sense of the need to implement the RF front-end in sub-modules: To manage the routing complexity and manage the interconnect losses from the RF transceivers to the sub-modules and from the sub-modules to the antennas. To manage the isolation needed between functions that will operate concurrently. To enable flexibility in supporting different level of features, band support, or regional skews. This is especially the case in FR2 where multiple band, SC, and blockage require mul- tiple arrays to be supported, as is illustrated on the right side of the block diagram. Here, unlike for FR1, it is not possible to multiplex non-adjacent bands to the same antenna system, and the mmWave transceiver needs to be as close as possible to the antenna as the losses associated with connection traces at these frequencies are impossible to recover. This is why the transceiver and antenna array constitute a single module in FR2: a module may have more than one array to support 28 GHz and 39 GHz bands, for example (as illustrated on the top-right corner of the block diagram). FR1: 410-7125 MHz FR2: 24.25-52.6 GHz Diversity MIMO1 MIMO2 Antenna Antenna Antenna Antenna Diversity Antenna Multiplexing MIMO Antenna Multiplexing Main Antenna Multiplexing MIMO Antenna Multiplexing 3.3-5 Wifi/BT MB-HB WiFi/LAA 1.2-1.6 1.6-2.4 2.5-2.7 3.3-5 1.6-2.7 3.3-5 mmWare TRX&Antenna Array Modules WiFi/BT module HB T/R HB&UHB HB&UHB RX Diversity module modules UL MIMO module RX-4x4 MIMO modules modules LB & MB FDD T/R modules IQ BB IQBBIQ BB|IQ BB IF TRX IC BT/WiFi TRX IC MODEM ga