臺灣博碩士論文加值系統

渦輪碼在功率限制加成性白色高斯雜訊通道中具有非常強大的錯誤更正能力，由Berrou等所提出的渦輪碼使用了兩個遞迴系統式迴旋碼平行聯結編碼，並利用反覆解碼演算法使其性能相當接近Shannon極限。渦輪碼的發現並沒有宣告錯誤更正碼時代的結束；相反的，它掀起了另一波編碼研究的熱潮。藉由使用渦輪法則，許多性能良好的錯誤更正碼持續地被發現，其中一項重要的課題為將渦輪碼應用於有效率利用頻寬的編碼調變技術。
編碼調變技術結合編碼與調變作整體設計考量，因此能獲得可觀的編碼增益而又不會增加頻寬的需求。區段編碼調變所產生的訊號碼為區段格式，籬柵編碼調變則是由籬柵碼產生訊號列。選擇適當長度的二元區段碼就可以建立性能相當優越的區段編碼調變架構，然而在實際應用上，如果區段長度太長，解碼複雜度會變得過於龐大而無法接受。
區段編碼調變所產生的不同區段是互相獨立的，一種稱之為具區段記憶編碼調變的架構所產生的不同區段之間具有編碼關聯性，這種獨特的編碼能夠提升碼率與編碼增益，同時其多層解碼演算法在每一層都有最佳性能與低複雜度。我們將引進聯結編碼與反覆解碼的觀念來降低具區段記憶編碼調變架構的位元錯誤率，預期將可獲得進一步的編碼增益。

Turbo-codes are very powerful codes for power limited AWGN channels. The turbo-codes invented by Berrou et al. use two parallel-concatenated recursive systematic convolutional codes. The iterative decoding algorithm is good to operate at only a fraction of a dB from the Shannon limit. The discovery of turbo-codes does not put an end to the story of error control coding. On the contrary, it has resulted in a renaissance of coding research. By using the ‘turbo’ principle, many related codes have been discovering. The application of turbo-codes in bandwidth-efficient coded modulation techniques is one of the important issues.
The coded modulation technique uses combined coding and modulation to achieve appreciable coding gains without sacrificing the bandwidth. Block coded modulation (BCM) is based on a block by block manner while trellis coded modulation (TCM) is based on a trellis code. We can easily construct BCM schemes with good error correcting abilities by choosing proper binary block codes. However, the huge decoding complexities for long block codes limit the practical usage of BCM with long block design.
Block coded modulation with interblock memory (BCMIM) is an improved BCM scheme. Compared to BCM for which each block is independent of the others, the introduction of interblock coding can increase the coding rates and coding gains. The associated multi-stage decoding algorithm is optimum in each stage and has low decoding complexity. We’ll improve the bit error rate performance of BCMIM by introducing the concept of concatenated coding and iterative decoding. It is expected that further coding gains will be obtained.

摘要……………………………………………………………………I
Abstract………………………………………………………………III
致謝……………………………………………………………………V
Contents..………………………………………………………………VI
Figure Captions………………………………………………………IX
Chapter 1 Introduction……………………………………………1
Chapter 2 Enhanced Block Coded Modulation Scheme with Single
Parity Check Codes……………………………………3
2-1 Background…………………………………………3
2-2 Block Coded Modulation……………………………5
2-2.1 Multilevel coding……………………………6
2-2.2 Code structure………………………………6
2-2.3 Set partitioning………………………………6
2-2.4 Minimum squared Euclidean distance
(MSED)………………………………………7
2-2.5 Decoding……………………………………11
2-3 Block Coded Modulation with Single Parity Check
Code…………………………………………………13
2-3.1 Code structure………………………………13
2-3.2 Decoding……………………………………15
Chapter 3 Turbo Block Coded Modulation with Interblock Memory……………………………………………19
3-1 Block Coded Modulation with Interblock Memory…19
3-1.1 Generator……………………………………19
3-1.2 Code structure………………………………20
3-1.3 Minimum Squared Euclidean Distance……20
3-1.4 Decoding……………………………………22
3-2 Turbo Block Coded Modulation with Interblock
Memory……………………………………………23
3-2.1 Code structure…………………………………23
3-2.2 Decoding………………………………………24
Chapter 4 Simulation………………………………………………26
4-1 Code structure 1………………………………26
4-2 Code structure 2…………………………………31
Chapter 5 Conclusion………………………………………………36

Figure Captions
Fig. 2-1 Simplified model of a coded system……………………………4
Fig. 2-2 BCM scheme……………………………………………………5
Fig. 2-2.1 Multilevel coding……………………………………………8
Fig. 2-2.2 The code structure of BCM……………………………………9
Fig. 2-2.3 Set partition of 8-PSK………………………………………10
Fig. 2-2.4 Multistage decoding…………………………………………11
Fig. 2-2.5 (8,1,8) trellis…………………………………………………11
Fig. 2-2.6 (8,7,2) trellis…………………………………………………12
Fig. 2-2.7 (8,8,1) trellis…………………………………………………12
Fig. 2-2.8 trellis of 8-PSK modulation BCM scheme…………………12
Fig. 2-3.1 Code structures of Enhanced BCM…………………………14
Fig. 2-3.2 The flow chart of decoding…………………………………17
Fig. 2-3.3 Decoding procedure…………………………………………18
Fig. 3-1.1 Configuration of coding……………………………………21
Fig. 3-2.1 Code structure of Enhanced BCMIM………………………25
Fig. 4-1.1 A coded block of code structure 1……………………………26
Fig. 4-1.2 Trellis of code structure 1……………………………………28
Fig. 4-1.3 Bit Error Rate (K=4;N=20)…………………………………29
Fig. 4-2.1 A coded block of code structure 2……………………………31
Fig. 4-2.2 Trellis of code structure 2……………………………………33
Fig. 4-2.3 Trellises of (8,4,4) and refined (8,4,4)………………………34
Fig. 4-2.4 Bit Error Rate (K=8 ; N=20)…………………………………35

[1] Do Jun Rhee; Sandeep Rajpal; Shu Lin; " Multi-level concatenated
block coded modulation schemes " Singapore ICCS/ISITA '92.
'Communications on the Move' , 16-20 Nov. 1992 Pages:1111 –1115
vol.3
[2] Li, H.-B.; Cioffi, J.M.; " Enhanced block coded modulation using
iterative decoding based on parity check codes " Communications, 2001. ICC 2001. IEEE International Conference on , Volume:
1 , 11-14 June 2001 Pages:315 - 319 vol.1
[3] Mao-Chao Lin; Shang-Chih Ma; "A coded modulation scheme with
interblock memory " Communications, IEEE Transactions
on , Volume: 42 , Issue: 234 , February-April 1994 Pages:911 –
916
[4] Mao-Chao Lin, Jia-Yin Wang and Shang-Chih Ma, "On block-coded
modulation with interblock memory " IEEE Transactions on
Communications, Volume: 45 Issue: 11 , Nov. 1997 , Pages:
1401 -1411.
[5] Heo, S.W.; Gelfand, S.B.; Krogmeier, J.V.; " Equalization combined
with trellis coded and turbo trellis coded modulation in the
nonlinear satellite channel " MILCOM 2000. 21st Century Military
Communications Conference Proceedings , Volume: 1 , 22-25 Oct. 2000 Pages:184 - 188 vol.1
[6] Banerjee, A.; Costello, D.J., Jr.; Fuja, T.E.; " Performance of hybrid ARQ schemes using turbo trellis coded modulation for wireless channels " Wireless Communications and Networking Conference, 2000. WCNC. 2000 IEEE , Volume: 3 , 23-28 Sept. 2000
Pages:1025 - 1029 vol.3
[7] Gass, J.H., Jr.; Curry, P.J.; Langford, C.J.; " An application of turbo trellis-coded modulation to tactical communications " Military Communications Conference Proceedings, 1999. MILCOM 1999. IEEE , Volume: 1 , 31 Oct.-3 Nov. 1999
Pages:530 - 533 vol.1
[8] Berrou, C.; Glavieux, A.; Thitimajshima, P.; " Near Shannon limit error-correcting coding and decoding: Turbo-codes. 1 " Communications, 1993. ICC 93. Geneva. Technical Program, Conference Record, IEEE International Conference on , Volume: 2 , 23-26 May 1993
Pages:1064 - 1070 vol.2
[9] SHU LIN ; DANIEL J. COSTELLO, JR.; " ERROR CONTROL CODING Fundamentals and Applications " Prentice-Hall,Inc. Englewood Cliffs, New Jersey 07632