Abstract

Overview

Realistic human downlink exposure to electromagnetic fields at 3.5 and 28 GHz is assessed in various indoor scenarios. This study leverages a hybrid of ray-tracing and finite-difference time-domain (FDTD) methods.

Findings

• Introduction of distributed massive multiple-input multiple-output (DMaMIMO) technology for 6G base stations at 28 GHz.
• Comparison of exposure with 5G base stations operating at 3.5 GHz.
• Detailed analysis of exposure clusters in DMaMIMO configurations which vary with power normalization.
• Influence of base stations to user distance in line-of-site (LOS) and non-line-of-site (NLOS) are discussed, highlighting a power law relationship and effects of shadowing.

Conclusion

The study reveals that all measured exposures lie significantly below the limits established by the International Commission for Non-Ionizing Radiation, showing a safe margin in current settings. Distributed base stations at equal power levels result in 2 to 3 times lower exposure than collocated base stations.