Millimeter-Wave Human Blockage in Wireless Communication Systems

Millimetre-wave (mmWave) frequencies promise ultra-high data rates and spectrum availability for emerging 5G and 6G networks, yet their short wavelengths render them highly susceptible to obstruction by the human body. When a user or pedestrian intersects a link’s line-of-sight path, the signal can suffer deep fades, diffraction loss and rapid temporal variations. To ensure reliable connectivity, researchers have characterised blockage phenomena through both empirical campaigns and high-fidelity channel sounding, developed hybrid geometrical-empirical propagation models, and devised adaptive beamforming and multi-point coordination strategies. These efforts span indoor small-cell deployments, vehicular and wearable applications, and backhaul links, highlighting the need to predict blockage events and to dynamically reconfigure antenna arrays or switch between alternative links. Advances in stochastic learning, real-time channel estimation and diffraction modelling now underpin robust system designs capable of sustaining multi-gigabit throughput in the presence of human-induced shadowing.

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Recent algorithmic solutions have focused on outage-minimisation in coordinated multi-point (CoMP) mmWave orthogonal frequency division multiplexing (OFDM) systems. A novel hybrid beamforming and per-carrier power-allocation scheme uses stochastic-learning to infer blockage probabilities, jointly optimising beamformers and power distribution to deliver outage performance comparable to schemes with perfect blockage knowledge, while requiring only a few radio-frequency chains.

On the modelling front, a point-cloud based diffraction-path extraction method for dynamic human-body shadowing at 300 GHz has been proposed. By reconstructing complex body geometries from high-resolution point clouds and applying a modified edge-representation technique, this approach yields up to four-times better accuracy than conventional vertical-screen models when predicting diffraction losses and Doppler shifts under realistic human motion.

Complementing these advances, a hybrid geometrical-empirical propagation model at 60 GHz integrates phase-accurate ray-tracing of direct, reflected and diffracted paths with empirically derived amplitude parameters. Validated over exhaustive measurement campaigns, this model achieves both computational efficiency and broad generality, enabling accurate simulation of human presence effects across diverse indoor scenarios.

Millimeter-Wave Human Blockage in Wireless Communication Systems publication trend

The graph below shows the total number of articles in millimeter-wave human blockage in wireless communication systems across all publications each year (not limited to Nature Index journals).

Technical terms

Millimetre wave (mmWave): Electromagnetic spectrum from 30 GHz to 300 GHz, offering high bandwidth but limited penetration and diffraction.

Line-of-sight (LoS): Unobstructed direct path between transmitter and receiver.

Diffraction: Bending of waves around the edges of an obstacle, resulting in additional propagation paths.

Beamforming: Technique to steer and shape antenna radiation patterns to focus energy toward desired directions.

Coordinated multi-point (CoMP): Network architecture where multiple transmission points collaborate to improve link reliability and data rates.

Uniform theory of diffraction (UTD): Analytical framework for calculating diffraction around objects with known geometry.

References

1. Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems. IEEE Transactions on Wireless Communications (2023).
2. Outage-Minimization Coordinated Multi-Point for Millimeter-Wave OFDM With Random Blockages. IEEE Transactions on Vehicular Technology (2023).
3. Point Cloud-Based Diffraction Path Extraction for Dynamic Human Body Shadowing Channel at 300 GHz. IEEE Open Journal of Antennas and Propagation (2025).
4. Geometrical-Empirical Channel Propagation Model for Human Presence at 60 GHz. IEEE Access (2021).