寬頻分碼多工系統中渦輪碼的交錯器設計

Abstract

渦輪碼在加成性白色高斯雜訊通道下有很好的錯誤訂正效果，近來由於一些新的渦輪碼交錯器設計加大幅的改善了渦輪碼在加成性白色高斯雜訊通道下的錯誤機率，因此渦輪碼交錯器設計更獲得很多人的注意。 在本篇論文中，我們考慮渦輪碼在以第三代行動通訊為標準的寬頻分碼多工系統的適用性，並特別討論及比較數種渦輪碼的交錯器設計，此外我們採用CRC檢驗來控制渦輪碼所需之重複解碼次數以縮短解碼的時間。模擬的結果指出，不同的渦輪碼的交錯器設計在瑞雷衰減通道中的效果是相同的，此外，使用CRC檢驗來控制渦輪碼所需的重複解碼次數能在不降低效能下有效的降低解碼時間。

Turbo codes have been shown to provide very good error correction performance over AWGN channels. Recently, turbo codes with different interleaver designs over AWGN channels have gained a lot of attention because using some specific interleaver design criteria a superior error performance can be obtained. In this thesis, we consider the applicability of such codes to the WCDMA systems for third generation mobile communication systems. Especially, the effects of several interleaver designs for turbo codes are discussed and compared. Besides, we use the turbo codes with CRC check to control the number of iterations to reduce the decoding time. The simulation results indicate that the performance of the turbo codes, using different interleaver designs, is almost the same over Rayleigh fading channels. Also, the turbo codes with CRC check to control iteration number can reduce the decoding time significantly without degrading the performance.