共查询到18条相似文献,搜索用时 125 毫秒
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在干扰背景下,集中式MIMO雷达可以通过设计发射波形提高系统的输出信干噪比,然而优化后的波形通常会具有较高的自相关旁瓣,降低了接收机对弱目标的检测性能。该文提出一种干扰背景下MIMO雷达部分相关信号设计方法。该方法在兼顾发射信号峰均比(PAPR)的同时,在发射天线对正交恒模波形进行加权处理,并以最大化接收机系统的输出信干噪比为准则建立目标函数,给出一种基于拟牛顿法的连续优化算法求解目标函数,获得最优加权,使得系统的输出信干噪比得到提升。仿真结果表明,该方法能够有效地抑制干扰,并可自适应地将发射信号能量辐射向目标方向,提高系统输出信干噪比。 相似文献
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针对星载船舶自动识别系统(AIS)中无法避免的信号混叠问题,研究了突发混叠信号单通道分离中广泛应用的逐幸存路径处理(PSP)与最大似然接收解调,提出了一种基于相位跟踪的AIS 信号单通道分离算法。该算法通过最小化混叠信号状态转移表中的欧氏距离,解决了信道估计与跟踪中由频偏和调制系数估计误差导致的相位畸变问题。仿真表明,该算法相位跟踪性能在归一化频偏误差(相对符号速率)大于2×10-2时仍然能收敛,该算法的解调误码率与抗频偏的PSP 算法及线性联合检测算法相比,当误码率等于10-3时,同道干扰信道下具有2 dB ~4 dB 的信干比性能优势。 相似文献
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为了更好地抑制全双工多入多出技术(MIMO)中继系统的自干扰,提高信息传输速率,提出了一种新型的波束成型组合算法。该组合在源节点和目的节点采用奇异值分解的波束成型向量,而在中继站采用基于最大化信干噪比接收波束成型来抑制中继端的自干扰,以及最大化信泄噪比发射波束成型矩阵来减少中继发送端泄漏到中继接收机的信号组合波束成型算法。为了降低复杂度,随后引入了交替迭代结构来进一步优化中继接收和发送波束成型矩阵,并比较了不同组合波束成型方案的和速率性能。仿真结果表明,与现存的波束成型组合相比,当干噪比较低时,提出的组合算法能够提供更优的和速率性能。 相似文献
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OFDM(正交频分复用)技术的主要缺点之一是其发送信号具有较高的峰均比。DFT(离散傅里叶变换)扩展OFDM系统的发送方案可以有效降低信号的峰均比。在该系统中,频域成型方法不仅对系统有无码间干扰的特性和抗噪声性能有重要影响,而且对发送信号的峰均比也有重要影响。文中首先在加性高斯白噪声信道下推导了无码间干扰和接收机最大输出信噪比条件下发送频域成型函数及接收频域成型函数所要满足的条件,然后根据该条件设计了几种频域成型方法。仿真结果表明,频域成型方法能进一步有效降低发送信号的峰均比。 相似文献
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为了降低双流通信系统接收端的信号处理复杂度,提出了一种基于第一路信息流解调信息进行双流信号解调的方法.该方法在接收端对接收到的两路信息流中的第一路解调后,获得相应的解调信息,并将该解调信息迭代回求出第一路信息流对应的发送信号以获得反馈符号流;再根据反馈符号流依次进行干扰消除和合并以获得合并信号,并据此对第二路信息流进行... 相似文献
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在雷达信号和通信信号一体化电子战系统中,需要处理的雷达信号和通信信号在时频域都是重叠的,存在很强的时频耦合,给信号检测带来很大的困难。讨论了作为干扰的强通信信号对宽带雷达脉冲信号非协作检测的影响,提出了一种基于分数阶Fourier变换的干扰抑制方法。该方法利用分数阶Fourier变换对不同信号的时域聚集特性,在分数阶Fourier变换域滤除干扰,提高了信号的信干比,改善系统对宽带脉冲的检测性能,该方法对存在多个通信干扰信号时仍然适用。仿真结果表明,该方法对提高系统检测宽带雷达脉冲信号的性能是有效的。 相似文献
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正交椭圆球面波函数脉冲调制方法 总被引:3,自引:0,他引:3
为了提高通信系统的功率效率和频谱效率,该文提出正交椭圆球面波函数(PSWF)脉冲调制方法。该方法利用具有高能量聚集性的椭圆球面波函数作为传输波形来提高通信系统的功率效率,采用时域正交、频谱混叠或交叠的正交脉冲组传输信息,以减小信息传输带宽,提高通信系统的频谱效率。理论分析及仿真结果表明,该方法可使通信系统的单位频带利用率快速接近2 Baud/Hz,且已调信号具有较好的频域能量聚集性,不仅有利于提高系统的功率效率,还可有效减小对相邻通信用户的电磁干扰。 相似文献
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DS-CDMA系统中结合多用户检测的功率控制研究 总被引:1,自引:0,他引:1
功率控制和多用户检测是CDMA移动通信中克服远近效应,抑制多址干扰(MAI)的两项关键技术。该文提出了一种在DS-CDMA系统中综合考虑功率控制和多用户检测的方案。该方案能更加有效地消除干扰信号,同时在满足信干比(SIR)要求时,所有用户发射总功率最小,收敛速度最快。 相似文献
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Lozano A. Tulino A.M. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2002,48(12):3117-3128
The capacity of wireless communication architectures equipped with multiple transmit and receive antennas and impaired by both noise and cochannel interference is studied. We find a closed-form solution for the capacity in the limit of a large number of antennas. This asymptotic solution, which is a sole function of the relative number of transmit and receive antennas and the signal-to-noise and signal-to-interference ratios (SNR and SIR), is then particularized to a number of cases of interest. By verifying that antenna diversity one can substitute for time and/or frequency diversity at providing ergodicity, we show that these asymptotic solutions approximate the ergodic capacity very closely even when the number of antennas is very small. 相似文献
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Joint Transmit Beamforming and Power Control for CDMA System 总被引:3,自引:1,他引:2
LI Ji-long CHEN Yu LI Chun-yuan ZHANG PingBeijing University of Posts Telecommunications Beijing P.R.China 《中国邮电高校学报(英文版)》2005,12(1)
1 Introduction Power control and beamforming are two main methods toreduce interference in CDMA cellular communication sys tem. In power control, the transmitters powers are constant ly adjusted when the instantaneous SIR is not equal to targetSIR, so that the quality of weak links is improved. Base sta tion equipped with antenna arrays may adjust their beam pat terns so that they have maximum gain towards the directionsof target mobiles and minimum gain towards the other direc tio… 相似文献
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Nicolae Dumitru Alexandru Alexandra Ligia Onofrei 《Wireless Personal Communications》2010,53(1):141-151
This paper is focused on the problem of reducing the intercarrier-interference (ICI) power in the transmission over Orthogonal
Frequency Division Multiplexing Systems (OFDM) using pulse shaping methods. A new pulse was proposed here and it was investigated
in terms of ICI interference. It appears to be suitable for transmission in OFDM systems with carrier frequency offset. The
results obtained by calculations show that the performance improvements are significant for reducing average intercarrier-interference
(ICI) power and increasing the ratio of average signal power to average ICI power (SIR). 相似文献
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Maehara Fumiaki Nakamura Osamu Takanashi Hitoshi 《Wireless Personal Communications》2000,15(3):181-197
We propose a novel SIR weighting postdetection combining diversity scheme with a new accurate SIR estimation method. The SIR is estimated and used as the weighting factor to compensate severe cochannel interference, one of the most important issues for PCS in terms of frequency utilization. Theimprovement offered by the proposal depends on SIR estimation accuracy.The SIR is, in this paper, estimated by a matched filter where theauto-correlation between received signal and unique word is calculated. Computer simulationsconfirm that the SIR of each diversity branch can be estimated easily andaccuratelyby the proposed SIR estimation method. The proposed diversity scheme achievesaperformance very close to that of ideal SINR weighting diversity underRayleighfading with severe cochannel interference. When average SIR = 10 dB and thenumber of branches(L)=4, the proposed diversity scheme lowers the requiredEb/N0 by 5 dB at BER = 1×10-3compared to conventional maximal ratio combining diversity. This paper alsopresentsthe unique word length required to realize adequate performance, i.e.,robustnessagainst high-pitch Rayleigh fading. 相似文献