Reducing the LOS ray beamforming setup time for IEEE 802.11ad and IEEE 802.15.3c

Beamforming (BF) protocols introduced in IEEE 802.11ad and IEEE 802.15.3c for 60 GHz millimeter-wave (mmwave) communications perform exhaustive sector/beam search to setup a beamformed link between stations/devices. In this paper, we propose two BF methods, Binary Search Beamforming (BSB) and Linear Search Beamforming (LSB), to improve the BF setup time of adopted algorithms in IEEE 802.11ad and IEEE 802.15.3c. The paper's premises are that the line-of-sight (LOS) ray dominates the mmwave links and the sectors with the highest antenna gains are the ones around the LOS ray direction. Proposed algorithms aim to find the sector covers the LOS ray in fewer steps by ignoring a number of sectors using iterative algorithms. This reduces the BF setup time significantly and saves power but at the expense of increased bit error rate (BER) in some cases. We provide performance comparisons of both algorithms with exhaustive search. For an example setup based on the channel model for a 60GHz system, simulation results show that, with 60 sectors antenna, the conventional BF setup time is reduced to 1.1% and 2.2% with using LSB and BSB, respectively. While not sacrificing from error performance for any number of sectors in the case of LSB, this is valid for only smaller than 36 sectors for BSB. However, in this condition, BSB has an advantage of around 3 dB power saving during the BF setup compared to LSB.