Technology has been fueling the global economy’s exponential growth over the past few centuries. 6G technology is expected to not only usher in the next wave of digital economic growth, but also drive far-reaching societal shifts in sustainability, digital equality, trust, and quality of life. The evolution in basic radio technologies is the most fundamental aspect of the next-generation cellular systems having a direct impact on canonical system Key Performance Indicators (KPIs). Part I of this white paper focuses on the fundamental 6G designs at the air interface level. While many of these technologies are starting to be discussed in 5G, they will likely not reach their full potential until 6G. Others represent fundamental departures from the concepts and architectures of 5G. Discussions of 6G are just starting, and we expect more new technologies to surface.