共查询到17条相似文献,搜索用时 156 毫秒
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自适应数字波束形成技术是一种以数字方法来实现波束形成的技术.它采用先进的数字信号处理技术对天线阵列信号进行处理,以获得优良的波束性能。本文在介绍自适应数字波束形成系统的基本组成和工作原理的同时,对其工程应用方面也做了较为详细的分析说明。 相似文献
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多波束抗干扰技术根据期望信号与干扰信号来向自适应形成主瓣和零陷,从而达到抑制导航干扰并增强期望信号的目的。多波束抗干扰技术的性能与阵列规模有着直接关系,更大规模阵列的抗干扰性能更好,但在工程应用中会受到算法收敛速度、硬件资源消耗与抗干扰处理实时性等方面限制,而小尺寸阵列抗干扰性能明显降低。针对这一问题,提出了一种多波束阵列重构导航抗干扰方法,针对不同期望信号与干扰信号来向分别进行优化,通过在全阵列中优化选取部分阵元组成最优子阵列,使用不同子阵列结构对不同来向期望信号进行波束形成。 相似文献
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针对宽带相控阵雷达中的关键技术如子阵划分、数字波束形成以及宽带自适应干扰对消等展开研究,给出了宽带阵列划分的准则和方法并以线性调频信号为例提出了一种数字波束形成方法和宽带自适应干扰对消算法。该方法应用数字时变相位补偿方法代替传统的时间延时单元形成主波束,降低了系统的复杂度并提高了波束形成的性能。基于拉伸处理的宽带自适应干扰对消算法对宽带旁瓣干扰和主瓣干扰都有较好的抑制作用,在强的宽带干扰下仍然可以很好地对目标进行高分辨成像。 相似文献
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针对于CDMA系统自适应天线阵列,提出了一种新的盲自适应MSINR(Maximum Signal-to-Interference plus noise ratio)波束形成算法.首先,将MSINR准则转化为一种新的无约束损失函数,并且从理论上分析该损失函数的性质.然后,应用自适应拟牛顿方法得到在线迭代波束形成算法.该算法无需训练序,而是利用CDMA信号自身的结构特点,结合空间处理提高了系统性能.最后,给出了仿真结果,表明算法具有较快的收敛速度和良好的动态跟踪能力. 相似文献
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一种用于CDMA系统的智能天线波束形成方法 总被引:2,自引:0,他引:2
在智能天线的实际应用中,波束形成所需的时间及其复杂度是决定其能否实施的主要因素。本文分析了CDMA通信系统的特点,提出了一种新的用于CDMA系统的波束形成方法。该方法带来的好处是放宽了对时间的要求和降低了系统的复杂度,权值的稳定性也得到了提高。该方法下的系统性能仿真结果表明,与全向天线相比,系统的信干比和误比特率得到很大改善。文章最后研究了不同参考信号下系统的性能,结果表明,在强干扰情况下,用判决信号作参考信号时系统性能将下降,应避免使用。 相似文献
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介绍一种用于阵列天线,利用信号恒模特性进行自适应波束形成的算法,即最小二乘恒模算法。它通过对阵列天线单元接收信号进行非线性处理,在保持期望目标信号的同时,可在多个干扰方向形成零陷,从而大幅度提高信干噪比(SINR)。文章通过对该算法的仿真对其性能进行了分析,最后阐述了基于该算法的阵列天线应用。 相似文献
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A novel adaptive beamforming algorithm for antenna array CDMA systems with strong interferers 总被引:12,自引:0,他引:12
Seungwon Choi Jinho Choi Heung-Jae Im Byungcho Choi 《Vehicular Technology, IEEE Transactions on》2002,51(5):808-816
Blind beamforming based on the maximum signal-to-noise ratio (MSNR) can improve the performance of an array system only when the processing gain of the given code-division multiple-access (CDMA) system is high enough such that the desired signal can become dominant after despreading (see Choi, S. and Shim, D., IEEE Trans. Veh. Technol., vol.49, p.1793-1806, 2000; Choi, S. and Yun, D., IEEE Trans. Antennas Propagat., vol.45, p.1393-1404, 1997). We consider a maximum signal-to-interference-plus-noise ratio (MSINR) beamforming. The MSINR performance criterion is chosen to deal with strong interferers effectively. It is shown that blind MSINR beamforming is possible by directly utilizing the input and output signals of correlators of the CDMA systems. In addition, we propose an adaptive beamforming algorithm at a lower computational complexity - about O(7.5N) - where N is the number of antenna elements of the array system. Simulation results are presented in various signal environments to show the performance of the proposed adaptive algorithm. 相似文献
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Adaptive MMSE receiver with beamforming for DS/CDMA systems 总被引:1,自引:0,他引:1
The minimum mean-squared error (MMSE) receiver is a linear filter which can suppress multiple access interference (MAI) effectively in direct-sequence code-division multiple-access (CDMA) communications. An antenna array is also an efficient scheme for suppressing MAI and improving the system performance. In this letter, we consider an adaptive MMSE receiver in conjunction with beamforming in CDMA systems employing an antenna array. The proposed structure is featured as a low complexity receiver, which adapts the MMSE filter coefficients and the beamforming weights simultaneously. However, it does require the channel state information and the direction of arrival (DOA) of the desired user signal. As a result, we propose two adaptation methods to perform joint channel estimation and signal detection without any training sequence. It is demonstrated that the two proposed methods achieve similar bit-error-rate performance. More importantly, their performance degradation compared with the case with perfect channel information is small. 相似文献
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《Vehicular Technology, IEEE Transactions on》2002,51(4):624-635
Using a transmit antenna array (TAA), the downlink beamforming is able to improve the performance of wireless communication systems. We propose a semiblind downlink beamforming method based on channel reciprocity of the wireless channels for code-division multiple-access (CDMA) systems equipped with TAA. In the proposed semiblind method, it is shown that the feedback delay can result in performance degradation under a time-varying fading channel environment. Hence, the performance of the semiblind method is satisfactory only when the maximum Doppler frequency is low or the feedback delay is not significant. To overcome this difficulty, the channel prediction is considered. Using the channel predictor, the semiblind method can provide a reasonable performance for a moderate maximum Doppler frequency (about a few hundred hertz). For theoretical performance analysis, upper, and lower bounds of the bit error probability under a fading channel environment are derived 相似文献
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This work compares the performance of various beamforming algorithms for the mitigation of multiple access interference in adaptive array code-division multiple-access (CDMA) systems. The Fourier and linear constrained minimum variance (LCMV) methods are both well-known algorithms for beamforming. While the LCMV method has many advantages, it can result in high noise gain under certain conditions. The recently developed amplitude and phase-estimation (APES) method has been shown to have better noise-gain performance. The APES filter is derived for the spatial case and simulation results are compared to those of both Fourier and LCMV under various scenarios of the CDMA reverse channel. Further, the effects of the use of multiple constraints on the beam pattern of LCMV and APES are investigated. 相似文献
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