Estimation of carrier frequency offsets with the extended kalman filter for MIMO-OFDM systems / Chun-Hsien Yeh.

[[abstract]]MIMO系統目前之所以如此備受矚目，主要是因為它能夠比SISO系統提供更大的容量。MIMO系統的優點主要有兩方面，首先，空間分集技術的運用將可使連結通道的可靠度獲得改善；再者，空間分工技術的運用將可以增加系統所傳送的資料速率。 當MIMO 系統和正交分頻多工一起被運用時，就可以在複雜的通道環境下去實現較高的空間效率。然而，缺點為MIMO-OFDM 系統仍然像SISO-OFDM系統一樣，對同步所造成的錯誤相當敏感，尤其是載波頻率誤差最為嚴重。針對這個問題，本篇論文提出利用一種稱為延伸式卡曼濾波器(EKF)來估側這瞬間的頻率偏移量。根據模擬的研究結果顯示，延伸式卡曼濾波器(EKF) 可以很快速的算出系統的頻率偏移量，並將頻率偏移量很快速的校正回來。此外，相較於其他文獻所提出的方法，其操作方法也更為簡便。[[abstract]]At present, multiple-input and multiple-output (MIMO) systems attract more attention mostly because they can provide higher capacity than do single-input and single-output (SISO) systems. For instance, channel reliability can be improved by means of Spatial-Diversity. In addition, the data rate can be increased by the use of Spatial-Multiplexing. When MIMO system and Orthogonal Frequency Division Multiplexing (OFDM) are employed simultaneously, there will be higher spectral efficiency achieved in the more complex channel environments. However, like the SISO-OFDM systems, the MIMO-OFDM systems are very sensitive to synchronization errors, especially the carrier frequency offset. In this present study, an alternative algorithm, an extend Kalman filter (EKF), is proposed to estimate the instantaneous carrier frequency offset. Compared with the approaches proposed in other studies, the Extend Kalman Filter (EKF) not only can track the frequency offset in MIMO-OFDM system and correct the carrier frequency offset more quickly, but also has less complexity