共查询到19条相似文献,搜索用时 78 毫秒
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从Turbo码在加性高斯白噪声(AWGN additive white Gaussian noise)信道下的理论分析出发,讨论了Turbo码在瑞利衰落信道下的算法改进。 相似文献
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衰落信道下Turbo码在宽带CDMA系统中的应用研究 总被引:5,自引:0,他引:5
本文在研究Turbo码在衰落信道下典型性能分析的基础上,提出了在宽带CDMA系统中结合RAKE接收机实现路径分集后Turbo码的性能分析方法.在高斯和衰落信道下,采用计算机仿真进行了实际系统的模拟,结果表明宽带CDMA系统中Turbo码对抗衰落的性能有了很大提高. 相似文献
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Turbo码以其优异的性能而迅速成为近年来信道编码领域研究的热点。本文针对无线信道的特点,提出了在无线衰落信道中Turbo码的构造方法,并基于非选择性瑞利慢衰落信道模型,分析了Turbo码在不同信道条件下的性能。 相似文献
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Petri提出了超正交卷积Turbo码(Superorthogonal Convolutional Turbl Gode,SCTC)^「1」。由于 宽的扩展,这类码的性能比一般的Turbo码好,本文推导了一般SCTC码的构,同时导出了存储单元分别为2,3的SCTC的转移函数。分别给出了高斯信道下非相关瑞利衰落信道下SCTC码的误码率性能上限,以及计算机模拟的高斯信道,非相关瑞处衰落信道和相关瑞利衰 相似文献
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针对卫星移动通信的连续信道帧结构的特点,设计了删除部分信息的打孔Turbo码.该码型通过删除传输信息特定位置上的系统信息或者校验信息,来提升Turbo码的码率,由此可在每组Turbo码的头部添加同步信息.通过仿真表明,合理设计打孔的长度和位置,可以获得较为理想的打孔Turbo码性能. 相似文献
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分组相关快衰落信道下自适应Turbo码译码算法研究 总被引:1,自引:1,他引:1
分析了分组相关快衰落信道的特性,推导出该信道下Turbo码译码算法;研究了迭代次数对Turbo编码系统的影响,在小信噪比弥散度条件下,提出基于平均信噪比的最佳迭代译码次数自适应选择方案,可以兼顾译码性能和译码速度,得到较低的平均误比特率和较高的平均译码速度。仿真结果说明,本文提出的Turbo码译码算法,降低了对信道估计精度要求的同时,得到精确信道估计时的性能;对于目标误比特率为10^-4时,采用自适应Turbo译码算法,与固定迭代4次相比,平均误比特率降低了40%,提高了系统性能;而与固定迭代8次相比,迭代次数降低了约1/4,提高了译码速度。 相似文献
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MultipathFadingChannelSimulationforMobileSatelliteCommunicationSystemGanZhongmin;LiuQianlin;QuDexin(CommunicationsEngineering... 相似文献
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针对规则LDPC码,采用了行列都均匀的(evenboth)随机构造H的方式,在瑞利平坦衰落信道下和卷积码的性能进行了对比,证明了规则LDPC码在中短帧传输下在瑞利平坦衰落信道的优异性能。这对LDPC码应用于实际无线通信系统具有重要参考价值。 相似文献
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Turbo码因其具有优异的编译码性能而成为国际空间数据咨询委员会(CCSDS)建议的卫星通信和深空通信编码标准。针对CCSDS标准Turbo码结构,设计了支持多码率、多帧长的优化编码器FPGA实现结构并在Altera StratixⅢ系列FPGA芯片上进行了验证,在资源占用很小的情况下达到了100 MHz以上的处理速率,该编码器已应用于某卫星上实现10 Mbit/s以上速率的数据编码。 相似文献
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一种准静态平坦衰落信道下空时编码设计的新方法 总被引:1,自引:0,他引:1
空时码在准静态平坦瑞利衰落信道下的设计准则被广泛采用的是秩准则和行列式准则,但这些准则并不是很紧的。为此,提出了准静态平坦瑞利衰落信道下一种新的更紧的设计准则,采用这种准则还大大降低了穷举搜索空时好码的复杂度,仿真结果表明,搜索得到的空时好码性能优于现有的其它好码。 相似文献
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Yasmine A. Fahmy Hebat-Allah M. Mourad Emad K. Al-Hussaini 《Wireless Personal Communications》2006,38(3):325-341
In this paper, a generalized multiple-input multiple-output (MIMO) antenna system that can be fitted to the uplink of a wireless communication system is considered for the general case of multi-user. At the transmitter, the information bits are Turbo coded, then interleaved and passed through a serial-to-parallel converter. The channel is assumed bad urban suffering from multipath Rayleigh fading resulting in inter-symbol and multiple access interferences (ISI and MAI). At the front-end of the receiver, a number of receiving antennas are used followed by a joint multi-user estimator based on the Minimum Mean Square Error Block Linear Equalizer (MMSE-BLE).Computer simulations demonstrate a significant performance improvement in both single user and multi-user cases.This paper depends in parts on that presented at the 11th European Wireless Conference, Cyprus, Nicosia, pp. 187–192, April 2005.
Yasmine A. Fahmy was born in Guiza, Egypt, on June 4, 1976. She received the B.Sc., M.Sc. and Ph.D. degrees in Communication and Electronics engineering from Cairo University, Egypt on 1999, 2001 and 2005 respectively. She is presently an assistant professor at Cairo University, Egypt. Her current field of interest is wireless communication and channel estimation.
Hebat-Allah M. Mourad received her B.Sc., M. Sc. and Ph.D. degrees in electrical communication engineering from Cairo University, Egypt, in 1983, 1987 and 1994 respectively. Since 1983, she has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently associate professor there. Her research interests include optical fiber communications, mobile and satellite communications.
Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London, UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding engineering research. He has written several papers for technical international journals and conferences. His research interests include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is a senior member of IEEE. He is listed in Marquis Whos Who in the World and in the IBC (International Biographical Center, Cambridge) for outstanding people of the 20th century. 相似文献
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差分跳频中,用户数据对频率选择的约束性比较弱。对此本文提出多序列跳频(MSFH)系统,其发送频率不仅是用户数据的函数,也受同步跳频序列严格约束,因此可以采用窄带接收更好地抑制带外干扰。具体地,数据分组从一簇相互正交的跳频序列中选出一个序列,该序列的当前频率由射频端直接发送,而无需对发送信号进行调制。得到了瑞利衰落信道中,未编码和采用卷积编码-硬/软判决Viterbi译码时MSFH符号误码率性能。计算和仿真表明,在相同编码增益下,MSFH误码率低于常规跳频系统;与差分跳频译码复杂度相当时,MSFH性能亦具有一定优势。 相似文献
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Mo Fan Kim Junghwan Dave Sameep Kwatra Subhash C. 《Wireless Personal Communications》2004,28(3):179-204
Practical implementation of convolutional turbo codec is impeded by the difficulty of real-time execution in high transmission
rate communication systems due to high computational complexity, iterative block decoding structure, as well as the requirement
of accurate on-line channel reliability estimation for maximum-likelihood decoding. Relying on innovative channel estimation
techniques involving DS-CDMA specific noise/interference variance estimation and fading channel variation tracking, this paper
provides a low-complexity all-digital design of an iterative SISO log-MAP turbo decoder for DS-CDMA based mobile communication
systems. The issues of quantization and data flow in both pre-decoder processing module and iterative trellis decoding module
are prudently addressed to ensure highly efficient hardware implementation. The efficient design strategies applied confine
the decoding complexity while leading to an excellent performance within 0.2 dB of the software decoder. 相似文献