Efficient Interpolation of Beamforming Vectors in MIMO-OFDM Systems

• Main Authors: Yu-Feng Chou, 周宇峰
• Other Authors: Tzu-Hsien Sang
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/19391079572469039746

碩士 === 國立交通大學 === 電子工程系所 === 96 === To fully exploit the channel capacity in multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems, beamforming vectors derived from SVD can be used at the transmitter and the receiver. The optimal beamforming requires accurate the channel state information for each OFDM subcarrier. This paper proposes a limited feedback and limited channel decomposition architecture by deploying a novel suitable interpolation method to reduce the computation cost of beamforming. In the proposed system, the receiver feedbacks only the estimated channel information on the pilot subcarrier and the transmitter use these channel information to get decomposition results on all subcarrier by an orthogonal interpolation method. This method is a circular interpolator with the important assumption that the singular modes on adjacent subcarriers approximately change in a linear way. Numerical simulations show that under certain circumstances, e.g., proper FFT size, interpolation gap etc., the proposed scheme can reduce computation efficiently while only sacrifice little performance.