Blind Channel Estimation for Orthogonal Space-Time Block Coded MIMO-OFDM systems

• Main Authors: Jian-Da Jiang, 江建達
• Other Authors: See-May Phoong
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/35148916014750976449

碩士 === 國立臺灣大學 === 電信工程學研究所 === 101 === Orthogonal frequency division multiplexing (OFDM) has recently received con- siderable interest for its advantages in high-bit-rate transmissions over frequency- selective fading channels. Space-time block coding (STBC) has emerged as a powerful approach to exploit spatial diversity and to combat fading in multiple-input multiple- output (MIMO) wireless communication systems This thesis studies the blind channel estimation for OFDM systems with multiple transmit antennas. The thesis consists of three parts. In the rst part, we review an existing channel estimation method us- ing subspace. This method though gives good performance but for many orthogonal STBCs (OSTBCs), it cannot uniquely identify the channels when only one receive antenna is available. In order to solve this issue, we propose an improved method. In the second part, we propose a new subspace-based method for blind channel esti- mation. The proposed method exploits the null space induced by the OSTBCs with rare < 1. The identi ability is also studied. In the third part, we introduce a modi- cation of the proposed method so that fewer received blocks are needed. Moreover the modi ed method has low computational complexity. We also provide numerical simulation to verify the performance of the proposed methods.