Abstract
Spatial multiplexing with transmit beamforming is a technique for multi-input multi-output (MIMO) systems to separate transmit streams that are sent from different antennas. Under the constraint of limited feedback bandwidth, the beamforming matrix must be quantized and then fed back to transmitter. The conventional method utilizes singular value decomposition (SVD) to design the precoder and the decoder, and then feedback the beamforming matrix to transmitter with vector-wise quantization based on Householder reflection. In this thesis, we propose a different approach using LU decomposition (LUD) to obtain the beamforming matrix. We show that LUD has lower computational complexity than SVD, and vector-wise quantization with LUD has better feedback efficiency than that with SVD. Finally the simulation results show LUD system has better bit error rate (BER) performance than SVD system.