共查询到19条相似文献,搜索用时 109 毫秒
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基于前导序列的突发通信载波同步算法 总被引:2,自引:0,他引:2
在突发通信中,载波同步技术是解调系统的核心和关键技术。给出了一种基于恒包络零自相关序列(CAZAC)作为前导的突发通信载波同步算法,该算法基于CAZAC序列零自相关特性,先用载波频差前向校正、载波相位前向校正进行载波初始同步捕捉,再用锁相环技术进行跟踪,能够在低信噪比下进行快速载波恢复。仿真结果表明,本算法的同步速度快,捕获的频率范围较宽。 相似文献
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针对MIMO SC-FDMA系统载波频率偏移敏感问题,本文提出一种基于OSIC的载波同步算法。该算法对载波频偏(CFO)的信号进行排序、零化、迭代均衡实现干扰消除。理论分析和仿真实验表明该算法实现了载波频偏干扰消除的目的,并且提高了系统性能。 相似文献
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针对多输入多输出(MIMO)技术的应用需要,研究了MIMO同步算法,提出了一种基于导频和信道估计的联合同步算法。该方法运用基于二阶矩的盲估计算法进行信道估计;再把信道估计的结果用最小均方误差准则做均衡,并设计一种特别的导频来估计载波频偏并估计信道时延。在不同条件下进行仿真,分析结果表明:在复杂信道环境下算法的性能相比传统算法有显著提高,研究结果对MIMO的工程应用有较好参考意义。 相似文献
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新一代数字电视广播标准DVB-S2在卫星通信中的应用越来越广泛,如何保证接收机能够在卫星信道的低信噪比和大频偏条件下正常工作是DVB-S2接收系统需要解决的关键问题。本文重点研究可以支持QPSK、8PSK、16APSK和32APSK四种调制方式的载波同步算法,在对已有载波同步算法分析的基础上提出优化设计方案,增强了解调器捕获频偏和适应低信噪比的能力,并可适用于高阶调制方式。仿真结果表明,本文的算法能正确完成DVB-S2信号的载波恢复功能,可以应用于卫星通信的接收系统。 相似文献
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为实现高动态突发通信系统载波快速同步,提出了一种新的基于前向结构的突发信号载波同步算法,采用多级处理方案分级实现多普勒变化率、多普勒频偏及载波相位的估计及恢复.理论分析及数值仿真表明,在高动态低信噪比条件下,新算法的载波同步信噪比损失小于1 dB,且对多普勒变化率及信号电平参数不敏感,实现复杂度低,能够满足高实时性应用需求. 相似文献
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定时同步和频率同步是影响MIMO—OFDM系统性能的关键因素。提出一种改进的帧同步算法并分析其仿真结果。仿真结果表明:该算法能够消除传统帧定时算法的平台效应,在提高帧同步精度的同时,对系统小数倍频偏估计性能也有所提高。 相似文献
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多媒体业务对无线通信的带宽与品质提出了更高的要求,OFDM和MIMO由于满足了这一需求被越来越多的无线通信标准采用所为底层的调制和传输技术。频率同步问题是OFDM—MIMO物理层设计中正确解调的前提和基础,本文介绍了OFDM—MIMO的原理、特点和频率同步问题的研究现状。 相似文献
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This article proposes a time/frequency synchronization algorithm in the multiple input multiple output (MIMO) systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages: 1) synchronization in time domain by signal autocorrelation; 2) synchronization in frequency domain by fast Fourier transform (FFT); 3) multipath dissociation using coherent detection and fine time synchronization; 4) fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio (SNR), the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability. 相似文献
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文中提出了一种新的MIMO-OFDM同步算法,该算法适用于各发射天线信号到达时延不同的情况,具有更广泛的意义,可用于分布式MIMO系统。 相似文献
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T. P. Sameer Babu P. M. Ameer R. David Koilpillai 《International Journal of Communication Systems》2023,36(15):e5563
Underwater acoustic channel is a challenging medium for communication due to the presence of significant multipath, high noise, frequency-dependent propagation loss, and high and non-uniform Doppler spread. Doppler shift is non-negligible in underwater communication due to the low velocity of underwater signals. Synchronization and Doppler estimation are important requirements for achieving good performance in this channel. Synchronization algorithms that give good performance in radio communication do not work well in underwater communication. Hence, this area has received a lot of attention from researchers. This paper surveys important works in the area. The techniques proposed in the literature for frame synchronization, frequency and phase synchronization, and timing synchronization in single carrier communications are reviewed here. The synchronization techniques proposed for OFDM, MIMO OFDM, and spread spectrum communication are also surveyed. Doppler estimation methods proposed in the literature are also reviewed. It is found that most of the recent works in underwater acoustic communication focus on OFDM synchronization. Deep learning-based methods proposed in the literature are also reviewed. Key open problems and areas that require future research attention in the field of synchronization and Doppler estimation in underwater communications are highlighted in this paper. The area needing most attention of underwater communication researchers was found to be MIMO OFDM due to the difficulty in synchronization in such systems while used in underwater communication. Reducing the computational complexity of the algorithms used is also important for future work. Schemes that work with Doppler due to relative velocity over 10 m/s also need to be developed. 相似文献
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未来的移动通信系统LTE的下行链路将广泛采用MIMO-OFDM技术。基于MIMO-OFDM系统的表达式和信道模型,以及Zadoff-Chu序列,提出了一种等周期的伪叠加Zadoff-Chu序列的集中式和分布式MIMO同步算法,并进行了仿真。仿真结果表明该算法能够准确地进行符号时间同步,验证了所提出符号同步算法的有效性。 相似文献
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与单载波直扩相比,多音调制直接序列扩频(Multi-tone DSSS,MT-DSSS)在相同频谱效率下具有更高的处理增益,但非正交子载波的频谱重叠导致其对载波同步更加敏感.分别在频偏及相噪两种情况下对多音调制(MT)系统载波同步误差进行随机过程建模,计算出相关检测判决统计量及平均误码率,并进行仿真验证.结论表明:在频... 相似文献