A Discussion About Achievable Data Rates of 6G MIMO Channels in Urban Microcells

Aiming to bridge the gap between practical data rates and simulated achievable data rates (ADRs), this work focuses on ergodic ADR analyses of 6G point-to-point multiple-input multiple-output channels in the frequency bands of 7.8 GHz and 15 GHz, when an urban microcell scenario is considered. Numerical results showed that the realistic ADRs are 46% of those obtained from ideal models, and the discrepancy between them grows as the number of antenna elements and signal-to-noise ratio (SNR) increase. Moreover, SNR-based metrics lead to biased performance comparisons across frequencies, whereas a TX-power-based framework enables fairer assessment. This framework reveals the inherent limitations of millimeter-wave communications, particularly at longer distances and under non-line-of-sight (NLOS) conditions. A comparison of the 7.8 GHz frequency band with the conventional 5G bands shows that it offers a compelling compromise between coverage and data rate, combining a wider bandwidth than the 3.5 GHz band with more favorable propagation characteristics than the 26 GHz band.