the United States. The 26 GHz band strategy for local networks is being decided during the second half of 2020. Japan Spectrum for local 5G has been released in Japan at the end of 2019 as shown in Fig. 1-8. This is intended for local government and enterprise use. Target is to realize "Society 5.0" through state-of-the-art technologies such as IoT, AI, robots, and self-driving vehicles, and their incorporation into all industries and sectors related to lifestyle. Unlicensed spectrum As mentioned earlier, mmWave spectrum is a key to unlocking 5G potential. Licensed mmWave spectrum for 5G is mainly in the 24-26, 28, and 39 GHz bands. Release 17 is intended to bring 5G support to the unlicensed 60 GHz band that was previously dedicated to 802.11ad/ay standards (with limited commercial success). Another option is to use unlicensed spectrum in <7 GHz bands. 3GPP defined the use of unlicensed spectrum already for 4G/LTE. In 5G, NR-Unlicensed 4600 MHz 4650 MHz 4700 MHz 4750 MHz 4800 MHz 4850 MHz 4900 MHz Local 5G (1) Local 5G (2) 3GPP N79 28.2 GHz 28.3 GHz 28.4 GHz 29.2 GHz Local 5G Local 5G (4) 3GPP N257 FIGURE 1-8 Japan Government/Enterprise 5G bands. 14 Open Radio Access Network (O-RAN) Systems Architecture and Design RAN Functional Components Low Physical High Physical PDCP/ DFE/RF MAC/RLC Layer Layer Transport FIGURE 1-9 RAN functional components. RAN, radio access network. (NR-U) standards define the use of what traditionally would be Wi-Fi spectrum for use with the 5G/NR waveform in a coexistence scenario. This allows Wi-Fi bands to supplement data through- put. This is known as LAA (License-Assisted Access) or "anchored NR-U" and this technology was not widely picked up for LTE-it is unsure how popular a LAA will evolve into NR-U will prove to be. Technology challenges to address when supporting NR-U include: spectrum sharing with existing users including Dynamic Frequency Selection, Listen- Before-Talk, and Transmit Power Control techniques and low transmit power support which constrains coverage to (largely) 