https://scholars.lib.ntu.edu.tw/handle/123456789/152185
標題: | 下世代無線網際網路用的多載波碼域多工收發機之研製--總計畫(3/3) | 作者: | 闕志達 | 關鍵字: | 多載波碼域多工;智慧型天線;通道參數估測;預失真補償;同步演算 法;基頻接收機 | 公開日期: | 31-七月-2004 | 出版社: | 臺北市:國立臺灣大學電機工程學系暨研究所 | 摘要: | 本計畫之主要目的是依據以前一 期電信國家型計畫有關WCDMA 收發機 研究成果為基礎提出以多載波碼域多工 (MC-CDMA)技術為主的下世代寬頻網際 網路無線傳輸系統。並依此規格需求建立 具備智慧型天線之下行收發機系統,含基 地台發射端與手機接收端,並對所建立的 系統進行實驗測試。 本計畫於第三年度內在演算法方 面,結合OFDM 調變技術與可適性天線 陣列系統,設計接收器分集架構。提出了 利用領航子載波進行通道估測的演算 法,使得接收機在高速移動的狀態下,仍 然可以得到正確的通道估測值。在電路架 構上提出一適用於多載波系統之低中頻 接收機,在ADC 之後加上一包含DDFS 及乘法器之全數位補償電路及可改善I/Q 不平衡狀況而使系統之鏡像干擾拒斥比 合乎所求。我們並以FPGA 元件完成電路 雛型實作以證實其可行性。此外亦完成了 基頻接收機的硬體架構設計並以IC 的形 式實現此基頻接收機。 In our previous project we have successfully built a 3GPP WCDMA base station receiver with smart antenna capability. This project uses the MC-CDMA as the downlink physical layer technique. This not only can complement our previous work on 3GPP uplink receiver implementation but also provides a backward-compatible evolutionary nextgeneration wireless standard for wide-band wireless internet services. In the third year, we have proposed a receiver algorithm for OFDM with receiver diversity that uses a new multi-user generalization of the maximum a posteriori probability (MAP) selection diversity combining followed by successive interference cancellation with least-square projection for multi-user detection. We have also proposed a novel frequency-domain Interpolation-based channel estimation algorithm for the MC-CDMA system based on pilot subcarriers. In addition, to combat the I/Q imbalance of the analog frontend, we have implemented a fully digital compensation circuit consisting mainly of a DDFS and two multipliers that can restore the IRR to acceptable level. Finally, the baseband receiver IC incorporating the proposed WLS error estimation as well as the channel estimation algorithm has been completed. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/8005 | 其他識別: | 922219E002009 | Rights: | 國立臺灣大學電機工程學系暨研究所 |
顯示於: | 電機工程學系 |
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922219E002009.pdf | 380.55 kB | Adobe PDF | 檢視/開啟 |
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