- 學位論文
改良式離散傅立葉通道估測技術於多種正交分頻多工通訊系統之應用
Improved DFT-Based Channel Estimation Techniques for Various OFDM Communication Systems
摘要
在無線通訊環境中，通道估測是非常重要的一個環節。本論文介紹了一個在時域的最小平方估測法在時域同步正交分頻多工系統。在近期的論文中，雙偽雜訊為訊號標頭的時域同步正交分頻多工系統被提出，用於保護通道估測所使用的訊號。在我們提出的方法中，利用了一些自我干擾消除的演算法，有效率的也即時的消除多重路徑干擾、訊符內干擾以及訊符間干擾。本論文也提出了改良式離 散傅立葉通道估測技術於 時域同步正交分頻多工系統。這個方法利用了顯著通道偵測演算法提升整體系統的效能。其中的關鍵點在於本演算法可以有效的估測雜訊的能量並且可以因此選擇出顯著的通道進而得到精準的時域估測通道響應。
並列摘要
Channel estimation is a very important issue in mobile communication environment. This dissertation introduces a time domain least-squares (TDLS) channel estimation (CE) technique for time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM). The dual PN-sequence padding (DPNP) TDS-OFDM has recently been proposed in many papers for protecting the signals for CE. The proposed technique takes advantage of several self-interference cancelation (SIC) methods to effectively and timely reduce multipath interference (MPI), inter-symbol interference (ISI) and inter-block interference (IBI). This dissertation also proposes the modified discrete Fourier transform (DFT)-based channel estimation technique for TDS-OFDM communication systems. The proposed technique based on the concept of significant channel tap detector (SCTD) scheme possesses the potentials to effectively improve the system performance of TDS-OFDM systems. The proposed estimation scheme can also roughly predict the noise power in order to choose the significant channel taps to estimate the channel impulse response.