Efficient Feedback of the Channel Information for Closedloop Beamforming in WLAN

Wireless system employing multiple antennas can enhance the performance using beamforming techniques at the transmitter, where beamforming coefficients are often based on channel information for each packet transmission. This may require a secure feedback channel from the receiver with the channel information. In order to reduce the network overhead as well as to track the channel variations in fading environments, it is necessary to have an efficient way to deliver this information with a small number of bits. We investigate an efficient feedback mechanism using Givens rotation that decomposes the beamforming matrix and reduces the overhead of feedback information by as much as 75% in WLAN system when compared with conventional quantization methods