共查询到16条相似文献,搜索用时 109 毫秒
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介绍了基于置信传播算法的LDPC码和积译码算法,分析其密度进行化特性,对不同消息空间中的量化译码问题进行研究,对采用不同量化方案时LDPC码在AWGN信道下的译码性能进行了仿真。仿真结果表明相对连续译码,中间变量6bit均匀量化会带来约0.4dB左右的损失,而10bit非均匀量化性能明显得到改善。合适的高阶量化译码可以获得接近连续译码的性能。 相似文献
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基于Turbo码编译码技术,在Rician衰落信道模型下,详细研究了Turbo码Log-MAP译码算法和SOVA译码算法在低Rician因子衰落信道下的性能,并结合调制技术对整个编译码系统进行Matlab仿真。仿真结果表明,在低Rician因子信道下,Log-MAP译码算法的性能优于SOVA译码算法。 相似文献
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根据实际中Turbo译码器硬件实现的重要性,提出了一种适合于并行计算的改进Log-MAP译码算法,即在其译码计算中间参数的过程中,将具有n个输入变量的最大近似算法max*运算简化为取最大值的max运算和相关函数的计算,减少了存储量,有效实现了低复杂度的Turbo译码器的硬件结构。将此改进的算法应用于CCSDS标准和Wi MAX标准中,仿真结果表明,所提出的简化的近似算法与传统的Log-MAP算法对比,有效降低了译码复杂度和时延,而且纠错性能接近Log-MAP算法,便于实际工程应用。 相似文献
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提出应用于多天线系统的空时编码是未来无线移动通信中极具前途的一种技术.文中在详细论述了空时Turbo 网格码的基础上,针对Log-MAP译码提出了优化方案.仿真结果表明, 新的算法在大大降低译码复杂度的同时较好地保持了译码性能, 使其非常接近Log-MAP 算法的译码性能,同时也非常有利于硬件实现. 相似文献
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用于Turbo迭代译码的近似Log-MAP算法研究 总被引:1,自引:0,他引:1
本文运用逼近论,研究Log-MAP算法的近似算法.本文提出了校正函数的一阶、二阶和三阶逼近多项式,并对近似式的逼近精度进行了分析和比较.本文将近似Log-MAP算法用于WCDMA turbo译码器中,对译码器在AWGN信道和平坦慢衰落信道上的纠错性能进行了仿真.仿真结果表明:一阶近似Log-MAP算法将Max-Log-MAP turbo译码器的纠错性能改进了0.2~0.3dB,二阶及三阶近似Log-MAP算法与原Log-MAP算法性能等价,优于Max-Log-MAP 算法0.3~0.5dB. 相似文献
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本文对Turbo码的Log-MAP译码算法进行了分析,与其它算法进行了比较,着重分析了信噪比失配对Turbo码译码性能的影响,在此基础上探讨了几种信噪比估计方法,并对此进行了模拟仿真. 相似文献
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对Turbo码的Log-MAP译码算法进行了分析,与其他算法进行了比较,分析了信噪比失配对Turbo码译码性能的影响,在此基础上着重探讨了自适应信噪比估计器估计SNRD的方法,并对此进行了模拟仿真。 相似文献
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Hao Wang Hongwen Yang Dacheng Yang 《Communications Letters, IEEE》2006,10(3):186-188
In this letter, a new method for decoding turbo-like codes is proposed to simplify the hardware implementation of Log-MAP algorithm. In our method, the multivariable Jacobian logarithm in Log-MAP algorithm is actually concatenated by recursive 1D Jacobian logarithm units. Two new approximations of Log-MAP algorithm based on these 1D units are then presented, which have good approximated accuracy and is simple for hardware implementation. We further suggest a novel decoding scheme that its complexity is near the Max-Log-MAP while the performance is close to the Log-MAP algorithm. 相似文献
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The iterative decoding in turbo code has very high decoding complexity. This paper adopts the improved Log-MAP algorithm for
decoding of Space-Time Turbo Trellis Code (ST-Turbo TC) in the slow Rayleigh fading channels. Using the MacLaurin formulae,
the proposed algorithm expands the logarithmic function of the Log-MAP. It makes the computation much easier and the operation
of the hardware system much faster. Simulation results show that the proposed algorithm performs very closely to the Log-MAP
algorithm for decoding of ST-Turbo TC in slow Rayleigh fading channels. 相似文献
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LTE系统中Turbo编译码仿真与性能分析 总被引:2,自引:1,他引:1
介绍了LTE Turbo编译码方法,基于硬件实现对编码和交织器的计算进行了简化,提高了编码效率,利用Matlab仿真分析性能,分别采用Log-MAP算法和Max-Log-MAP算法进行译码,实现时结合项目需求综合考虑采用了误码率性能较好的Log-MAP算法。 相似文献
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Hau T. Ngo Author Vitae Author Vitae Ming Z. Zhang Author Vitae Author Vitae 《Integration, the VLSI Journal》2008,41(4):474-488
A high performance digital architecture for the implementation of a nonlinear image enhancement technique is proposed in this paper. The image enhancement is based on an illuminance-reflectance model which improves the visual quality of digital images and video captured under insufficient or non-uniform lighting conditions. The algorithm shows robust performance with appropriate dynamic range compression, good contrast, accurate and consistent color rendition. The algorithm contains a large number of complex computations and thus it requires specialized hardware implementation for real-time applications. Systolic, pipelined and parallel design techniques are utilized effectively in the proposed FPGA-based architectural design to achieve real-time performance. Approximation techniques are used in the hardware algorithmic design to achieve high throughput. The video enhancement system is implemented using Xilinx's multimedia development board that contains a VirtexII-X2000 FPGA and it is capable of processing approximately 63 Mega-pixels (Mpixels) per second. 相似文献