On the optimal beam selection with partial subcarriers on wideband mmWave systems

Utilizing wide bandwidth available in the millimeter wave channel is a promising candidate for the 5G and beyond 5G wireless sytems. To overcome severe channel degradation in millimeter wave channel, adopting massive MIMO with directional beamforming is essential, and base station and user should acquire best analog transmit/receive beam pair to establish a reliable link. The best analog transmit/receive beam pairs are found by maximizing a performance metric over the whole bandwidth. For efficient use of wideband in mmWave channel and to save energy at user, bandwith part (BWP) is adopted in NR which the user can be configured to use only a part of whole bandwith. With BWP, a user cannot use whole frequency information for best analog beam selection. In this paper, we have studied the impact of partial use of sub-carriers on the best analog transmit/receive beam selection.