- 學位論文
超寬頻多頻帶正交分頻多工系統下窄頻干擾消除方法之DSP實現
DSP Implementation of Narrowband Interference Cancellation Algorithms for MB-OFDM Based Ultra-Wideband Communication System
摘要
由於在超寬頻多頻帶正交分頻多工(multiband orthogonal frequency division multiplexing ultra-wideband ， MB-OFDM UWB)系統的傳輸環境下，和全球互通微波存取(worldwide interoperability for microwave access ， WiMAX)此系統有著相同的傳輸頻段，因而造成了這兩種共存的通訊系統在傳輸頻譜上的重疊；而根據系統的特性，全球互通微波存取造成了一個相對的窄頻干擾於超寬頻多頻帶正交分頻多工系統，並降低了系統的效能。有鑑於此，針對在接收端前使用的窄頻干擾消除演算法，已被廣泛的研究並驗證[1]，其可以顯著的降低系統錯誤率，改善系統效能。 此論文將上述超寬頻多頻帶正交分頻多工系統的傳輸環境搭配三種窄頻干擾(narrow-band interference，NBI)消除的演算法: 可適性最小均方誤差濾波器(LMS adaptive filter)、陷波濾波器(Notch filter)與頻譜轉移(Band dropping)，分別定義了浮點數與定點數運算並完整的程式化，下載至由德州儀器公司所生產的TMS320C6713 數位信號處理發展板(digital signal processor starter kit，DSK)中進行模擬與實現。過程中，根據此數位信號處理器的特性以及運算能力修改程式結構，已達到最有效率的處理程序。最後根據實驗結果，分析三種窄頻干擾演算法在處理效能、佔用的硬體資源上等比較，藉此提供現實環境中硬體實現的參考。
並列摘要
The multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) system suffered from the narrowband interference (NBI) due to the presence of coexistence communication system, such as worldwide interoperability for microwave access (WiMAX). If we deal with the NBI problem before the receiver, the performance of MB-OFDM UWB system can be significantly improved. The NBI cancellation algorithms have been proposed and verified, which could mitigate the interference efficiently [1]. In this paper, the Digital Signal Processor (DSP) implementation of three NBI cancellation algorithms are presented to improve the performance of MB-OFDM UWB system. We implemented the algorithms in both floating point and fixed point arithmetic using the TMS320C6713 DSP Starter Kit (DSK) from "Texas Insturment Inc.", and we optimized the algorithms to meet the realistic restriction, in terms of execution speed, code length and accuracy. Finally, some statistics such as resource occupied and time consumed are compared in Code Composer Studio™ (CCS) profile.