Joint Beamformer and Beamformee Design for Channel Smoothing in WLAN Systems

This paper investigates the combination of beamforming and channel smoothing for wireless local area network (WLAN) systems. Although channel smoothing is widely adopted in WLAN systems to improve the initial channel estimates, the combination of channel smoothing and beamforming has not been successful up to date. The difficulty of this combination is due to the existence of discontinuities in the beam-steering matrix across subcarriers. It destroys the frequency correlation of the beamformed channel matrix, which is unsuitable for the channel smoothing. In this paper, we propose a joint transceiver design of the beamformer and beamformee to provide a smooth beam-steering matrix. The simulation is performed extensively based on the IEEE 802.11ac link-level simulator, which shows that significant gains from channel smoothing are possible due to the proposed transceiver design.