Speaker: Ishhanie Majumdar ee12s058
Multi-user MIMO (MU-MIMO) technology has gained considerable application due tothe fact that it can greatly increase the information capacity of wireless communicationsystems. However, there is a phenomenon which has a limiting effect on MU-MIMO broadcast transmissions besides various other physical limitations, known as multi-user interference (MUI) which is our problem of interest. There are techniques to mitigate MUI known as precoding which are employed typically at the transmit side. A study of a class of linear precoding algorithms known as block diagonalization (BD) type precoding algorithms is performed. The mathematical details of these algorithms are presented in this thesis. We have implemented these algorithms in a OFDM based framework complying with WLAN standard IEEE 802.11ac. The investigation of these
algorithms include comparison and analysis of their BER performance and achievable sum-rate for 160 MHz IEEE 802.11ac channel.
IEEE 802.11ac provides beamforming technique known as null data packet (NDP)
beamforming. This beamforming standard includes a feedback mechanism known as compressed beamforming matrix feedback. We have performed a mathematical analysis of a MU-MIMO system with one of the precoding algorithms considered in this work along with the aforementioned feedback mechanism. The implementation of this feedback mechanism in ourMIMO-OFDMframework includes the aforesaid precoding algorithm. We observe that the system with compressed beamforming matrix feedback works as good as perfect feedback.