許大山臺灣大學：電信工程學研究所施凱挺Shih, Kai-TingKai-TingShih2007-11-272018-07-052007-11-272018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/58828當我們面對一個包含了內部錯誤更正碼和外部錯誤更正碼的串接編碼系統時，傳統的解法是分成兩個階段。首先，內部解碼器根據其所使用的準則來找出最好的碼字，然後將這最好的碼字傳遞給外部解碼器來檢查是否正確。然而，這種傳統解法的效能並不是最好的。如果將內部解碼器改成不只產生最好的碼字，同時還產生多個很有可能也是對的碼字給外部解碼器，則串接編碼系統的效能可以有效的得到提升。 在本論文中，我們提出一個新的演算法：「干擾解碼演算法」。干擾解碼演算法藉由給予內部解碼器許多受到干擾的接收信號來產生其他很有可能的碼字。干擾解碼演算法的觀念可適用於大部分的內部碼和外部碼的組合。因為干擾解碼演算法不需要使用精緻複雜的內部解碼器，所以非常的適合直接在IC 上的實現，且相較於傳統的解法，干擾解碼演算法可以至少提升1 dB 的效能。We consider a concatenated coded system consists of an inner error correcting code and an outer error detecting code. In a conventional decoding scheme, the inner decoder produces the best codeword from its perspective. The best codeword is then checked by the outer decoder. The performance of the concatenated coded system can be improved by having the inner decoder produce not only the most likely candidate but also other highly likely candidates. In this paper, we propose a new algorithm called "perturbed decoding algorithm"(PA). In PA, other highly likely candidate is produced by feeding the inner decoder with slightly perturbed versions of the received signal. The concept of PA is compatible with most combinations of inner code and outer code. Because PA does not require the use of a sophisticated inner decoder, it is straightforward to implement in silicon technology. From our simulation, PA can achieve a performance gain greater than 1 dB.1 Introduction 1 1.1 Motivation . . . . . . . . . . . 1 1.2 Background and Related works . . . . . 2 1.3 Contribution and Organization . . . . . 3 2 Perturbed decoding algorithm 5 2.1 Conventional concatenated code system . . . . . 5 2.2 Inner decoder which produces multiple candidate codewords . . . . . 6 2.3 Perturbed decoding algorithm . . . . . . . 8 2.4 Two operational parameters for PA . . . . . . . 10 3 Performance analysis of perturbed decoding algorithm 11 3.1 Single-bit error probability of PA . . . . . . . . 11 3.1.1 Problem formulation . . . . . . . . . . 11 3.1.2 Four joint probabilities . . . . . . . . 13 3.1.3 Single-bit error probability of PA . . . . . . 15 3.2 The uncoded frame error probability of PA . . . . . 17 3.2.1 Problem formulation . . . . . . . . . . . 17 3.2.2 The uncoded frame error probability of PA . . . . 19 3.3 The coded frame error probability of . . . . . . . 22 3.3.1 Simulation environment and parameters . . . . . 23 3.3.2 The coded frame error probability of PA . . . . 24 3.3.3 Effect of the power of perturbation noise . . . 25 3.3.4 Observed statistics on the number of re-decoding . . 27 3.4 Effect of using CRC . . . . . . . . . . . . . . . . 28 4 Complexity Comparison 31 4.1 List decoding algorithm . . . . . . . . . . . . . 31 4.2 Storage requirement and average decoding time . . . . . . . 33 5 Conclusions 34 5.1 Conclusions . . . . . . . . . . . . . . . . . . . 34 5.2 Future works . . . . . . . . . . . . . . 35 Bibliography 37 A How to choose the combination of inner and outer codes 39 A.1 Problem formulation . 40 A.2 Undetected error probability . . . . . . . . . . 41 A.3 Conclusions . . . . . . . . . . . . . . . . . 42 B The draft analysis for the upper bound on coded FER of PA 44 B.1 Review the upper bound on FER of convolutional code . . 44 B.2 The upper bound on coded FER of PA . . . . . . . . 46599000 bytesapplication/pdfen-US干擾列表解碼演算法串接系統perturbednoisechase algorithmlist decoding algorithmthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58828/1/ntu-95-R93942096-1.pdf