Antenna Module Placement Optimization for Robustness to Hand Blockage

Good antenna module placements that are robust to hand blockage are essential for enhancing the user experience at millimeter wave carrier frequencies. This problem has been primarily addressed in a qualitative manner based on tradeoffs in terms of user equipment (UE) layout, available real estate, and a qualitative assessment of likely hand holding modes. In this study, we propose a quantitative modeling of this problem by considering statistical models for the likelihood of being in different hand holding modes and the angles of arrival in azimuth and zenith (AoA/ZoA) of the dominant clusters in the channel between the base station and the UE. By incorporating these statistical models with a candidate set of locations for the antenna modules, we can compute the effective spherical coverage of signal strengths for the determination of good antenna module placements. The effective part of the spherical coverage corresponds to the set of directions of AoA/ZoA likely to be seen for the dominant clusters and weighted by the likelihood of observing a blockage/no blockage scenario in the relevant directions. We show that the use of only one antenna module in the UE can lead to significantly poor coverage and increased outages. With the usage of a pair of antenna modules at the UE, our studies show that a good placement corresponds to placing one of the modules on the middle of the top edge to provide robust coverage for Portrait-type orientations and another module on the middle strip of the back face or in the middle portion of one of the long edges to provide robust coverage for Landscape-type orientations.