An automatic gain controller for MIMO-OFDM WLAN systems

MIMO-OFDM based wireless LAN standards are currently being defined. These systems employ packed-based communication, which requires fast and accurate automatic gain control. The precise estimation of the expected receive signal power of data symbols, based on preamble symbols is required in order to optimally detect the data signals. In this paper, two different preamble OFDM-symbols are considered and analyzed with regards to their suitability for received signal power estimation in MIMO-OFDM systems. An AGC architecture for an IEEE 802.11a based MIMO system is proposed and FPGA implementation results are reported.