基於獨特碼架構之頻域等化單載波系統之FPGA實現

Abstract

頻域等化之單載波系統(SC-FDE)在新一代之無線通訊系統中佔有相當關鍵性的地位，它不但能夠達到和正交分頻多工(OFDM)系統相當近似之效能和效率，亦同樣具有低訊號處理複雜度之優點。另一方面，SC-FDE並不會面臨OFDM所面對之高峰值對均值功率比(PAPR)問題，因此在IEEE 802.16標準中， SC-FDE成為了於OFDM以外另一實體層技術的選擇。在本論文中，吾人將使用自行研發之平台，實現一基於獨特碼(UW)架構之單載波系統，其中基頻演算法部分將實現於平台之Xilinx Virtex-II FPGA模組。在此系統中之演算法除包括通道估計器、頻率修正器、迴旋碼解碼器等之外，吾人也實現了基於獨特碼架構下之相位追蹤器，使得此一單載波系統之功能性更加完整。此外，吾人更進一步提出此一獨特碼架構於相位追蹤以外之應用，包括於時脈偏移下用以修正FFT窗之偏移，以及於移動之環境下用以更新通道之估計等。最後，本篇論文中將說明獨特碼的架構不但在理論上十分簡單，實際上也十分適合用於硬體平台的實現。

In recent years, Single Carrier System with Frequency Domain Equalization (SC-FDE) becomes a key technology in the development of new wireless communication systems. It has similar performance, efficiency as well as low signal processing complexity advantages as orthogonal frequency division multiplexing (OFDM), but does not suffer from the high peak to average power ratio (PAPR) problem as in OFDM system. Therefore, SC-FDE has been adopted by IEEE 802.16 standard as an alternative technique to OFDM in the physical layer. In this thesis, we propose a solution for building up a Unique-Word (UW) based SC-FDE system on a self-designed platform with Xilinx Virtex-II FPGA module mounted. In addition to channel estimator, frequency offset compensator and convolutional encoder, a UW-based phase offset tracker is realized to make the functionalities of the system more complete. Moreover, other applications of UW structure are presented, including FFT window synchronization and update of channel estimation in mobile environment, etc. Finally, we will show that the UW structure is not only theoretically simple, but also practically suitable for hardware implementation.