Chapter 27: Millimeter-Wave and Sub-THz Communications

Learning Objectives

• Characterise mmWave and sub-THz propagation using the close-in (CI) free-space reference distance path loss model and compare LOS/NLOS channel parameters across 28, 39, 73, and 140 GHz bands
• Analyse blockage effects including the exponential blockage model, human-body shadowing, and foliage attenuation, and quantify their impact on link reliability
• Design hybrid analog-digital beamforming architectures and evaluate spectral efficiency versus fully digital baselines as a function of the RF chain ratio
• Explain beam management procedures including beam sweeping, beam tracking, and beam failure recovery in 5G NR at FR2 frequencies
• Evaluate FR3 upper mid-band spectrum (7-24 GHz) coexistence constraints with incumbent services and achievable secondary system performance
• Describe sub-THz (100-300 GHz) channel characteristics including atmospheric absorption peaks, near-field beam focusing, and the transition from far-field to near-field MIMO