非連續性頻帶頻域預編碼式正交分頻多工 於感知無線電之應用

Abstract

在本篇論文中，探討了感知無線電中的非連續性頻帶頻域預編碼式正交分頻多工(spectrally precoded non-contiguous orthogonal frequency division multiplexing, SP-NC-OFDM)系統等相關技術，首先，我們研究了頻域預編碼式正交分頻多工的頻譜特性，在預先設計某個整數參數J之下，為了確保功率頻譜的旁波(sidelobes)衰減的程度是近似 f-2J-2，並以IEEE 802.22無線區域網（Wireless Regional Area Network，簡稱「WRAN」）標準來做工程上功率限制的模擬。 第二，我們研究了特定頻帶功率最小化(specific-band power minimization)技術，由於頻域預編碼式正交分頻多工的鄰近旁波(near-sidelobe)不易滿足的IEEE 802.2中之 FCC 遮罩(Mask)，是以我們採用特定頻帶功率最小化技術來達到抑制鄰近旁波的效果，同樣我們做了工程上的模擬。最後，我們結合頻域預編碼技術及特定頻帶最小化技術於非連續性頻帶正交分頻多工架構下，由於預編碼系數為資料獨立(data-independent)，是以在第四章我們只重新推導此架構下的特定頻帶最小化編碼系數，同樣也做了工程上的模擬。

Non-contiguous spectrally precoded orthogonal frequency division multiplexing (SP-NC-OFDM) techniques is investigated in this thesis. First, the spectral characteristic of SP-OFDM is studied. SP-OFDM guarantee power spectral sidelobes decaying asymptotically as f-2J-2 with J being a predesigned integer-valued parameter. Next, we simulate power spectrum density of SP-NC-OFDM with the standard of IEEE 802.22 Wireless Regional Area Network(WRAN) in engineering. Second, specific-band power minimization (SBPM) techniques is studied. Since the Spectrally precoded signal has large near-sidelobe power so that it is not easy to satisfied the constraint of the 802.22 FCC Mask. Thus, we embrace specific-band power minimization(SBPM) techniques to suppress near-sidelobe power and we also simulate power spectrum density in the view of engineering. Finally, we combine non-contiguous spectrally precoded orthogonal frequency division multiplexing with specific-band power minimization. Since spectral precoder is data-independent,we only derive specific-band power minimization code coefficient in CH.4 and we also do simulation as CH.2 and CH.3.