Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/48900
標題: Study of Golay Sequences in Pre-Transformed OFDM Systems
前置轉換正交分頻多工系統中格雷序列之研究
作者: 陳後守
關鍵字: 應用研究
電信工程
摘要: This project proposal investigates the Golay complementary sequences in a Pre-transformed OFDM system. The principle of orthogonal frequency division multiplexing (OFDM) is to split a high rate bit stream into several parallel low rate data substreams and use these substreams to modulate a number of orthogonal subcarriers. Recently, a novel modulation scheme, which combines the Walsh-Hadamard transform with OFDM (WHT-OFDM), is under investigation. In WHT-OFDM, the Walsh-Hadamard matrix is added before the fast Fourier transform (FFT) or equivalently the transmitted data is first spread by the discrete-time Walsh-Hadamard sequences and then modulated with the continuous-time sinusoidal signals. Thus, a WHT-OFDM system is equivalent to a combination of multi-code CDMA and OFDM.Golay sequences of OFDM can be obtained from certain cosets of the first order Reed-Muller (RM) code within the second order RM code. As with OFDM, we have derived some results regarding the binary Golay sequences in WHT-OFDM, which also composed of some certain second-order cosets of first order RM codes. Moreover, based on these results, we have shown that the number of binary Golay sequences in WHT-OFDM is much larger than those in OFDM systems. In the first year of this proposal, we would like to extend these results to nonbinary WHT-OFDM system, by classifying and enumerating the WHT-OFDM Golay sequences on QAM modulations. Since OFDM and WHT-OFDM systems are special cases of two-step orthogonal transforms which consisting of one discrete-time and one continuous-time orthogonal transforms, therefore, we will also consider the Golay sequences for other discrete-time transforms, in addition to Walsh-Hadamard transform in the second year of this proposal.
本計劃將探討前置轉換正交分頻多工系統(OFDM)之格雷序列。正交分頻多工系統之主要原理是將高速的串列資料轉換成低速並行資料,然後將這些低速並行資料掛於正交載波上。這幾年來,結合哈達碼轉換與正交分頻多工系統形成哈達碼正交分頻多工系統(稱為WHT-OFDM)也逐漸受到重視並有廣泛之研究出現。其基本原理是將資料先做哈達碼轉換再將之掛於正交分頻多工系統之載波上。因此WHT-OFDM系統可視為多碼CDMA系統與OFDM系統之結合。正交分頻多工系統之格雷序列可以經由位於二階裡德碼之特定一階裡德碼之陪集所產生。在WHT-OFDM系統中我們已經有了一些不錯的結果,比如我們證明出WHT-OFDM系統中二元格雷序列也是由一階裡德碼之陪集所形成,我們導出了其基本形式並算出WHT-OFDM系統二元格雷序列之個數。從這些結果我們發現WHT-OFDM系統二元格雷序列之形式與正交分頻多工系統之二元格雷序列不同且其個數遠比正交分頻多工系統之二元格雷序列更多。在本計劃中第一年我們將嘗試將這些結果推廣至非二元格雷序列,我們將考慮WHT-OFDM系統於QAM的調變下之非二元格雷序列。另外OFDM系統與WHT-OFDM系統皆為兩階段正交轉換之特例,其中前階段轉換通常為非連續正交轉換,後階段轉換則通常為連續正交轉換。因此在本計劃中第二年我們也將研究在使用非哈達碼轉換下之其他前置轉換所產生之格雷序列的基本形式與個數。
URI: http://hdl.handle.net/11455/48900
其他識別: NSC96-2221-E005-005-MY2
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=1441908&plan_no=NSC96-2221-E005-005-MY2&plan_year=96&projkey=PB9607-2003&target=plan&highStr=*&check=0&pnchDesc=%E5%89%8D%E7%BD%AE%E8%BD%89%E6%8F%9B%E6%AD%A3%E4%BA%A4%E5%88%86%E9%A0%BB%E5%A4%9A%E5%B7%A5%E7%B3%BB%E7%B5%B1%E4%B8%AD%E6%A0%BC%E9%9B%B7%E5%BA%8F%E5%88%97%E4%B9%8B%E7%A0%94%E7%A9%B6
Appears in Collections:電機工程學系所

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.