Jonit non-coherent detection and side-information extraction for lower-compleity PTS-based OFDM systems

結合非同調檢估與旁訊息檢測之低複雜度部分傳輸序列式正交分頻多工系統

蘇忠政(Jhong-Jheng Su)

指導教授 ： 翁詠祿

國立清華大學/電機資訊學院/電機工程學系/碩士(2011年)

https://doi.org/10.6843/NTHU.2011.00058

摘要

In this thesis, we propose a joint non-coherent detection and side-information extraction technique for the PTS-based OFDM systems. A drawback of the PTS-based OFDM is its high complexity for searching the optimal weighting phase vector. Based on the Trellis Factor Search (TFS) algorithm presented in the literature, we propose an iterative trellis factor search (ITFS) algorithm to reduce the search complexity of the PTS. Simulation results show that, the ITFS algorithm can reduce PTS search complexity efficiently. We extract side-information at receiver by using non-coherent detection which was originally used in non-coherent communications. The proposed system can be extened to the MIMO PTS-based OFDM system. In order to reduce the use of training symbols, the Differential Space-Frequency Block Code (DSFBC) and the Fourier Based Unitary Space-Time Modulation (USTM) are applied to the proposed system. Simulation results show that both DSFBC and Fourier based USTM can achieve a good PAPR performance and a satisfactory BER performance.

關鍵字

正交分頻多工 ； 功率均峰比 ； 多輸入多輸出 ； 部分傳輸序列

並列摘要

在這個論文中,
我們針對使用部分傳輸序列式(PTS)技術的正交分頻多工(OFDM)
系統提出了一個結合非同調檢估與旁資訊擷取的接收器。一個使用
部分傳輸序列技術的正交分頻多工系統最主要的問題便是在於搜尋
最佳的權重相位因子需要花費相當大的複雜度。基於樹狀因子搜尋
演算法(TFS),我們提出了一套疊代式樹狀因子搜尋(ITFS)
演算法，使用疊代式樹狀因子搜尋(ITFS)演算法的主要目的在於減少
搜尋最佳權重因子的複雜度。實驗結果顯示，疊代式樹狀因子搜尋演
算法能夠有效降低部分傳輸序列的搜尋複雜度。另外,我們還將原本用於非同調通訊系統中克服通道衰弱(fading)相位問題的檢測方式用來擷取旁資訊並且確保該技術不會造成錯誤系統效能的減低。我們所提出的系統同樣可以延伸至多天線輸入輸出(MIMO)的部分傳輸序列正交分頻多工系統中。同時為了減少訓練符號(pilot symbol)
的傳輸,我們將差分空頻編碼(DSFBC)與傅立葉式么正空時調變
(Fourier-based USTM)應用到我們的多輸入輸出部分傳輸序列正交分頻多工系統中。實驗結果顯示,差分空頻編碼與傅立葉式么正空時調變同樣具有相當好的功率峰均比(PAPR)並且有令人滿意的錯誤率效能。

並列關鍵字

Orthogonal Frequency Division Multiplexing ； Peak-to-average power ratio ； Multiple-input multiple-output ； Partial transmit sequence

參考文獻

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[4] B. S. Krongold and D. L. Jones, ”PAR Reduction in OFDM via Active Constellation Extension,” IEEE Trans. Broadcast., vol. 49, no. 3, Sept. 2003, pp. 258-68.

[5] L. J. Cimini, Jr. and N. R. Sollenberger, ”Peak-to-Average Power Ratio Reduction of an OFDM Signal Using Partial Transmit Sequences,” IEEE Commun. Lett., vol. 4, no. 3, Mar. 2000, pp. 86 - 88.