Channel Estimation Method for OFDM Systems

[[abstract]]在高速時變通道環境下，需要時變的通道估測才能滿足性能需求，利用訓練符元(Training symbol)和引導載波(Pilot tones)的觀念和學長的時變通道曲線估測法(Curve-fitting method)結合，提出非對稱引導載波時變曲線估測法。為了簡化其運算複雜度利用兩段式時變曲線估測法，在相同的效能之下能有效降地至少50%的運算複雜度。從模擬結果中可看出，在使用相近的overhead情況下，不但能利用有效的資訊量準確估出通道響應，且在複雜度方面也有明顯地減少。[[abstract]]A modified time-varying channel estimation method for orthogonal frequency division multiplexing (OFDM) systems is presented. The presented method makes use of asymmetric training symbols in combination with high-order polynomial fitting, and can thus obtain precious estimation results even under very large normalized Doppler frequency. To further reduce the computation complexity of the present channel estimation method, a modified two-step channel estimation method is also proposed. The modified two-step channel estimation method can maintain the same estimation performance but with at least 50% reduction in computation complexity.[[note]]碩