Performance of Beamforming for a Handheld Device in Measured 21.5 GHz Indoor Channels

This article presents an evaluation of the performance of two different approaches for beamforming (BF) in a fifth generation (5G) handset, based on measured channels from a dual-polarized transmitter (Tx) to a mockup handset with a seven-element receiver (Rx) array. The measurements at 21.5 GHz include both small-scale and large-scale channel changes and were conducted for different users holding the mockup at different locations in an indoor corridor environment. The unique measurements enable novel results based on the statistics of the power achieved with BF, using channel state information (CSI) measured at a 90 Hz rate, and both when using beam scanning (BS) and the equal gain combining (EGC) reference case. For the case of ideal CSI knowledge, BF gains of up to about 18 dB were found. However, when the density of the angle scanning grid is reduced and the CSI is delayed to realistic values, the average performance decreases by 8 dB. More results are given in the article.