第五代蜂巢式系統領航訊號汙染抑制方法之研究與模擬

Abstract

對於第五代蜂巢式系統通道估計時所面臨的領航訊號汙染問題，在本篇論文當中，我們提出了兩種有效的疊代式通道估計方法。因為領航訊號數目的限制，如果它們在不同的細胞中重複的使用，就會產生領航訊號汙染問題。我們所提出的的兩種疊代式方法是在疊代時分別只使用資料訊號、將領航訊號和資料訊號共用兩種不同方法來做通道估計。由於我們是採取領航訊號和資料訊號疊加的方式傳送訊號，所以在做通道估計時資料訊號也會成為干擾，我們所提出的方法可以讓資料訊號不再只是干擾而是對於通道估計有所幫助。模擬的結果顯示，我們所提出的方法能夠在適當的疊代次數下就到達理想的位元誤碼率。

In this thesis, we propose two kinds of iterative channel estimation method to suppress the pilot contamination phenomenon in 5G cellular mobile radio communication systems. Due to pilot sequence reuse in different cells, the estimated channel would be contaminated by neighboring cells which use the same pilot. To solve the pilot contamination problems caused by pilot sequence reuse, we first use estimated data sequence as a pilot signal to execute iterative channel estimation. Secondly, as the pilot and data sequences are transmitted in a combined manner, our second proposed method utilizes data sequence as an auxiliary pilot signal in addition to utilizing the orthogonal pilot signal when executing channel estimation. Our simulation results show that these methods can achieve the required BER performance within a acceptable number of iterations.