Patent ID: 7940638
Filing Date: 2011-05-10
Classification: H04L

Abstract:
1. A multiple-input multiple-output (MIMO) system comprising: a MIMO communication station having two or more antennas; and a plurality of mobile stations, the plurality of mobile stations comprising both single-antenna mobile stations having a single antenna and MIMO mobile stations having two or more antennas, wherein during a preamble of a frame, the MIMO communication station is configured to transmit training tones by each antenna only on every N wherein N is the number of antennas used by the MIMO communication station for transmitting the preamble, wherein the MIMO mobile stations are configured to estimate channel coefficients of two or more spatial channels for communications with the MIMO communication station based on receipt of the transmitted training tones, and wherein the single-antenna mobile stations are configured to estimate channel coefficients for a single channel for communications with the MIMO communication station based on receipt of the transmitted training tones.