Rate-feedback schemes for MIMO-OFDM wireless LANs

Through the widespread use of laptop computers and other mobile equipment, wireless LANs have significantly grown in popularity over the past few years. To meet the increasing data rate requirements of future wireless LANs, different physical layer improvements are currently being discussed within the IEEE 802.11n standardization group. This paper considers feedback schemes to increase the data rate and range of a multiple antenna (MIMO) OFDM WLAN system. As is shown, a simple feedback scheme based on switching on/off subcarriers/subchannels can achieve gains up to 3 dB while requiring minimal overhead for feeding back information to the transmitter.