公开(公告)号：US20220247465A1

公开(公告)日：2022-08-04

申请号：US17165368

申请日：2021-02-02

Applicant: Cisco Technology, Inc.

Inventor： John Martin GRAYBEAL ,  Paul Anthony POLAKOS ,  Robert Edward LISTON ,  Wai-Tian TAN ,  Xiaoqing ZHU

IPC: H04B7/06 ,  H04B7/0456 ,  H04L25/02 ,  H04B7/0452

Abstract: Multi-User Multiple Input, Multiple Output (MU-MIMO) data transmissions are provided with a forward-predictive precoding matrix to mitigate the effects of a change in a state of a communication channel. First and second soundings are performed, at first and second times, to a receive antenna over a channel and, responsive to each of the soundings, first and second Channel State Information (CSI) are received. Based on the first and second CSI, a change in a state of the channel over a time period between the first and second time is determined. Based on the change in the state of the channel, a forward-predictive channel state matrix and/or a forward-predictive precoding matrix are determined that reflect a state of the channel at a future time and that are consistent with the determined change in the state over the time period. The forward-predictive precoding matrix is applied to a data transmission.

公开(公告)号：US20210282108A1

公开(公告)日：2021-09-09

申请号：US16812427

申请日：2020-03-09

Applicant: Cisco Technology, Inc.

Inventor： Malcolm M. SMITH ,  Xiaoqing ZHU ,  Jerome HENRY

IPC: H04W64/00 ,  H04W24/10 ,  H04B7/06 ,  H04B7/08 ,  G01S5/02

Abstract: Techniques for determining a range between a wireless station (STA) and a wireless access point (AP) using channel state information are described. An AP determines channel state information corresponding to an STA. The AP determines, based on the channel state information, one or more fine timing measurement (FTM) parameters. A plurality of FTM messages are transmitted between the AP and the STA, based on the one or more FTM parameters. The STA is configured to determine an estimated range to the AP based on the plurality of FTM messages.