Adaptive beamforming structure with STBC for IEEE 802.11n WLAN systems

This paper proposes a structure of adaptive beamforming system especially tailored for IEEE 802.11n compliant WLAN operating in multiple input-multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) mode. The proposal defines beamforming system for 802.11n transceiver exploiting space time block coding (STBC) of MIMO technology. The proposed structure is based on adaptive computation of complex beamforming matrices at transmitter and receiver side for every OFDM subcarrier. For proposed structure, single-link single-user system model with detailed hardware architecture of 4x4 802.11n transceiver is presented using matrix algebra. In addition, solutions related to adaptive beamforming for proposed MIMO-OFDM system with variable number of transmitted spatial streams are shown in this paper.