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基于最小二乘法的高动态条件下抗频偏的精确同步方法 总被引:1,自引:0,他引:1
如何在高动态条件下实现精确同步是当今军事作战中必须解决的一个技术难题。在此条件下,码率偏移和载波频偏会影响精确同步的精度。该文提出一种改进的基于最小二乘法的伪码(PN)相位测量方法,并通过理论分析和仿真验证该方法在高动态条件的精确同步能力。理论推导可知,该方法消除了载波频偏的影响,并且具有强的抗噪声能力。数值仿真说明在选择PN序列不长的情况下该方法对码率偏移不敏感,并证明其具有很强的抗频偏能力。最终得到的测量结果说明该方法不仅有很高的测量精度,同时具有很好的抗噪声和频偏能力。 相似文献
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Traditional channel equation methods are based on the multi-path richness hypothesis, which is complicated and inefficient in sparse channels. In this paper, a sparse multi-path channel equation method is proposed. The sparse channel estimation is carried out using a small number of pilot tones based on Compressed Sensing (CS). The equation inverse filter is derived from the channel estimation. The procession of inverse filter solution is modeled as an optimization problem and a greedy algorithm is proposed which can bring about a near optimal solution. The new algorithm requires fewer iterations than linear prediction and gets almost optimal filter parameters when the rank is high enough. The modularized structure of the greedy algorithm is designed which is less complicated and can be easily realized. Simulation shows that the BER performance of the proposed equation method is improved significantly with the increase of SNRs. At 15dB of the SNR it gains 10dB in power efficiency relative to LMS. 相似文献
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基于多速率内插和最小二乘法的精确同步方法 总被引:1,自引:0,他引:1
最小二乘法可以利用PN序列相关曲线的对称性实现对接收端接收到的PN序列的相位精确测量。然而实际应用中无线信道带宽有限,接收端还原出来的PN序列只能在极性上和原来的方波形式保持一致,这样导致了相关曲线的变形,因而限制了最小二乘法的实际测量精度。为了进一步改善最小二乘法的测量精度,引入了多速率处理的方法,在不提高前端AD采样频率的基础上,通过增加鉴相曲线零点附近的鉴相点个数,使所用于拟合直线的点更靠近零点,从而提高系统测量精度。仿真结果表明,经过两倍内插后的方法相比内插前在测量性能上有三倍左右的提高。因此经过多速率处理改进后的方法可以显著提高系统对PN相位的测量性能。 相似文献
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