双多进制正交扩频系统的比特软值输出算法
Bit Soft-Output Algorithm for Dual N-ary Orthogonal Spread Spectrum System
-
摘要: 该文针对双多进制正交扩频与Turbo码的联合系统，基于最大后验概率(MAP)准则，提出了双多进制正交扩频输出比特软值的MAP算法，并给出了简化MAP算法；同时，对算法的定点和浮点性能进行了仿真，且与现有的软值算法进行了比较。结果表明，MAP算法能使整个系统获得相当的增益，L=3 的简化MAP算法在基本不增加复杂度情况下好于现有的双最大值算法约0.4dB。
-
关键词:
- Turbo码;正交码;最大后验概率算法
Abstract: Focusing on Turbo-coded dual N-ary orthogonal spread spectrum system, this paper proposes an algorithm for computing bit soft metric based on Maximum a Posteriori Probability (MAP) criterion, and then presents a simplified MAP algorithm. Meanwhile, the fixed-point and float-point performances are simulated and compared with several existing algorithms. It is shown that MAP algorithm greatly improves the whole system performance; the simplified MAP algorithm with L=3 outperforms the dual-maxima algorithms 0.4dB without extra cost in complexity.. -
Jalloul L M, Holtzman J M. Performance analysis of DS/CDMA with noncoherent M-ary orthogonal modulation in multipath fading channels. IEEE J. on Select. Areas Commun., 1994, 12(6): 862870. .[2]Berrou C, Glavieux A, Thitimajshima P. Near Shannon limit error-correcting coding and decoding: Turbo-codes (1)[J].IEEE Int. Conf. Communications ICC93, Geneva, Switzerland. May.1993, 2/3(5):10641071-[3]Li Bin, Tong Wen, Wang Rui. Multiple-symbol detection for orthogonal modulation in CDMA system. IEEE Trans.on VT,2001, 50(1): 321.325.[4]魏胜群，程云鹏，沈良．一种新的双多进制正交扩频复合调制方案．军事通信抗干扰学术研讨会, 合肥, 2003: C. 242.246．[5]孙文江，张平，胡健栋，正交序列扩频多码CDMA系统在AWGN信道的性能分析，通信学报，1998, (10): 52.58.[6]Proakis J G. Digital Communication, 4th ed. New York: McGraw-Hill, 2001: 300.307.[7]Hagenauer J, Offer E, Pake L. Iterative decoding of binary block and convolutional codes[J].IEEE Trans. on Inform. Theory.1996, 42(3):429-[8]Hagenauer J. Source-controlled channel decoding. IEEE Trans. on Commun., 1995, 43(9): 24492457. .[9]Pyndiah R M. Near-optimum decoding of product codes: block turbo codes[J].IEEE Trans. on Commun.1998, 46(8):1003-[10]刘东华 编著．Turbo码原理与应用技术．北京：电子工业出版社，2004, 第6章. -
计量
- 文章访问数: 2427
- HTML全文浏览量: 100
- PDF下载量: 815
- 被引次数: 0
下载:
