To efficiently support innovative services on a massive scale, 6G needs to address challenges related to RF circuits and subsystems among other challenges. This white paper illustrates a baseline transceiver architecture to set the stage for subsequent discussions. Transceiver (TRX) design challenges such as the carrier frequency, Local Oscillator (LO) frequency generation, link budgets, High Order Modulation (HOM), beamforming, Integrated Sensing and Communication (ISAC), Non-Terrestrial Network (NTN), and AI/EDA tool are discussed. Challenges related to ADCs, LNAs, and PAs are described along with the insights gained from the historical performance trends of these components. Research imperatives that can play an important role in solving the design challenges are summarized. FR3 research imperatives including the front-end architecture, power amplified efficiency, and HOM are discussed. Research imperatives of sub-THz LO frequency generation and the NTN are also described.

Initial studies indicate that scaling in frequency (especially at THz) may incur very high costs in terms of component performance, power, and capital from a hardware perspective. The applications that THz supports will need to justify the exponential increases in capital cost and power consumption. On the other hand, the hardware and power costs associated with the FR3 bands are relatively moderate. The FR3 bands would additionally benefit from spectrum sharing because this would compensate for the inability to leverage THz-levels of bandwidth.

6G is expected to be AI-native. To fully capitalize on AI/ML advancements, it is essential to examine the trade-offs and design challenges associated with integrating dedicated computational resources for implementing ML-based RF algorithms.