在塊狀時空碼補零系統下基於子空間方法之盲通道估測廣義演算法研究

Generalized Algorithms for Subspace-based Blind Channel Estimation in Space-time Coded ZP Systems

游尚益(Shang-Yi Yo)

指導教授 ： 蘇柏青

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00483

摘要

本論文探討塊狀時空碼補零系統之盲通道估測。不同於一般的通道估測，盲通道估測並不需使用額外的頻寬來估測通道係數。在本論文中，我們提出一種在塊狀時空碼補零系統下的廣義基於子空間方法盲通道估測演算法。我們的方法基於重複使用接受信號並使用一個叫做重複指數的參數。只要適當的調整重複參數，則演算法所需接收的符號數將會大大的下降。我們另外也提出一種稱為共軛方法的技巧。此方法能更進一步提高通道估測效能。此外，我們也整理出通道係數、來源符號與預編碼器的條件使得此演算法能正常被使用。最後，當接收的符號數量與重複指數適當的被選擇時，模擬結果也展現出我們所提出的演算法優於前人所提出的方法。

關鍵字

盲通道估測 ； 子空間方法 ； 塊狀時空碼

並列摘要

Blind channel estimation in space time block code (STBC) block transmission systems equipped with zero padding (ZP) is considered in this thesis. Different from pilot-based channel estimation, blind channel estimation does not require extra bandwidth to identify channel coefficients. In this thesis, we proposed a subspace-based blind channel estimation algorithm with generalized precoders in STBC-ZP systems. Our approach is based on repeated use of received signals and has a system parameter called repetition index. If we select repetition index carefully, the number of received blocks required can be significantly reduced. Another technique, namely the conjugate method, is also proposed to further enhance the channel estimation performance. In addition, we summarize the conditions on channel coefficients, source symbols, and precoders for the proposed blind algorithms to perform channel estimation properly. Finally, simulation results show that the proposed algorithms outperform previously reported methods when the number of received blocks and repetition index are properly chosen.

並列關鍵字

Blind Channel Estimation ； Subspace method ； Space-time block code

參考文獻

[1] J. Chuang and N. Sollenberger, “Beyond 3G: wideband wireless data access based on OFDM and dynamic packet assignment,” IEEE Communications Magazine, vol. 38, no. 7, pp. 78 –87, Jul 2000.

[2] A. Naguib, N. Seshadri, and A. Calderbank, “Increasing data rate over wireless channels,” IEEE Signal Processing Magazine, vol. 17, no. 3, pp. 76 –92, May 2000.

[3] S. Alamouti, “A simple transmit diversity technique for wireless communications,”IEEE Journal on Selected Areas in Communications, vol. 16, no. 8, pp. 1451 –1458, Oct 1998.

[4] B. Lu and X. Wang, “Space-time code design in OFDM systems,” in Proc. IEEE GLOBECOM, vol. 2, pp. 1000 –1004, 2000.

[5] N. Al-Dhahir, “Single-carrier frequency-domain equalization for space-time block-coded transmissions over frequency-selective fading channels,” IEEE Communications Letters, vol. 5, no. 7, pp. 304 –306, Jul 2001.