共查询到20条相似文献,搜索用时 55 毫秒
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在移动通信中采用波束赋形算法,可以更好地利用天线的空分性能和发射功率,但是需要考虑算法的收敛速度和计算速度。如果移动用户穿过蜂窝小区时速度很快,那么即使是短时间内位移量也很大。而赋形算法如果收敛慢或者没有检测到这个变化,就会仍然针对原来的问题进行计算,从而跟踪不到用户,影响通话。介绍了移动通信对波束赋形算法的要求,分析了两种基于种群技术的数字波束赋形算法。 相似文献
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智能天线自适应波束赋形算法的研究 总被引:1,自引:0,他引:1
智能天线作为3G及未来移动通信的核心技术,是当前通信领域的研究热点。阐述了智能天线的基本原理,并对自适应波束赋形算法进行了分类,较为详细地比较和分析了几种算法的特点及其适用条件。基于算法的现状,提出了未来的研究方向。 相似文献
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《信息技术》2016,(1)
波束赋形天线技术可以通过基带调零等手段降低干扰信号影响,提升系统抗干扰性能,通过数字信号处理还可以在空间上形成多个波束,从而形成空分多址,大幅度提升系统的容量。但是波束赋形天线技术要求天线间隔尽可能小,一般约为工作频率的半波长,而较小的天线间隔在实际工程实现时会引起严重互相耦合。由于对互耦效应进行有效的数学描述非常困难,一般通过计算量极大的专业天线仿真软件进行仿真验证,严重制约了互耦效应解决方案的提出和论证。文中针对上述问题,提出了互耦效应的数学模型,并利用MATLAB和ANSYS-HFSS工具对相关模型进行了交叉验证。不同平台的对比仿真结果显示了相关模型的正确性和有效性。 相似文献
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阵列信号在实际应用中,常常会面临噪声的干扰,低信噪比(signal noise ratio, SNR)时波束形成器性能会急剧下降.针对该问题,提出一种基于改进互耦系数估计的抗互耦算法的自适应波束形成,即研究信号在不同输入SNR以及不同干扰波达方向(direction of arrival,DOA)估计误差下的互耦系数估计误差;并通过误差分析修正原算法不同SNR下参与估计信号的数目.改进算法改进了导向矢量和期望信号,提高了低SNR下互耦系数估计的准确度,对比分析验证了其在低SNR情况下有更强的抗干扰能力,对互耦现象有着更好的稳健性. 相似文献
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A novel low-loss air-spaced patch antenna array with an integrated beamforming network is presented. The performance of the array is predicted using a commercial simulator. The predicted results are compared with measured data and good agreement is reported. 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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Jian Yang Hongsheng Xi Feng Yang Yu Zhao 《Vehicular Technology, IEEE Transactions on》2006,55(2):549-558
In this paper, the maximum signal-to-interference-plus-noise ratio (MSINR) beamforming problem in antenna-array CDMA systems is considered. In this paper, a modified MSINR criterion presented in a previous paper is interpreted as an unconstrained scalar cost function. By applying recursive least squares (RLS) to minimize the cost function, a novel blind adaptive beamforming algorithm to estimate the beamforming vector, which optimally combines the desired signal contributions from different antenna elements while suppressing noise and interference, is derived. Neither the knowledge of the channel conditions (fading coefficients, signature sequences and timing of interferers, statistics of other noises, etc.) nor training sequence is required. Compared with previously published adaptive beamforming algorithms based on the stochastic-gradient method, it has faster convergence and better tracking capability in the time-varying environment. Simulation results in various signal environments are presented to show the performance of the proposed algorithm. 相似文献
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Wideband smart antenna theory using rectangular array structures 总被引:1,自引:0,他引:1
Smart antenna techniques at the base station can dramatically improve the performance of the mobile radio system by employing spatial filtering. The design of a fully spatial signal processor using rectangular array configuration is proposed. Two-dimensional (2-D) spatial filters that can be implemented by microstrip technology are capable of filtering the received signal in the angular domain as well as the frequency domain. Furthermore, it has wideband properties and, hence, eliminates the requirement of different antenna spacing for applications including various carrier frequencies. The desired frequency selectivity of the smart antenna can be combined with compensation of the undesired frequency performance of a single antenna element, and the result is quite satisfactory for practical implementation. In addition, if the elements of the array are not perfectly omnidirectional or frequency independent, we can compensate for these deficiencies in the design algorithm. Two different algorithms for calculating the real-valued weights of the antenna elements are proposed. The first algorithm is more complex but leads to sharper beams and controlled performance. The second method is simpler but has wider beam and lower fractional bandwidth. Some computer simulation results demonstrating the directional beam patterns of the designed beamformers are also presented. 相似文献
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The performance of the combined beamforming of space-time block coding according to the number of antenna array groups has been analysed. CB/spl I.bar/STBC/spl I.bar/single array and CB/spl I.bar/STBC/spl I.bar/double array were compared under the condition of DOA and SNR. CB/spl I.bar/STBC/spl I.bar/double array is shown to have a stable performance independent of DOA and angular spread. 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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GaoFeng LiuQizhong ShanRunhong ZhangHou 《电子科学学刊(英文版)》2004,21(4):342-345
This letter investigates an efficient design procedure integrating the Genetic Algorithm (GA) with the Finite Difference Time Domain (FDTD) for the fast optimal design of Smart Antenna Arrays (SAA). The FDTD is used to analyze SAA with mutual coupling. Then,on the basis of the Maximal Signal to Noise Ratio (MSNR) criteria, the GA is applied to the optimization of weighting elements and structure of SAA. Finally, the effectiveness of the analysis is evaluated by experimental antenna arrays. 相似文献
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Directional power-based admission control for WCDMA systems using beamforming antenna array systems 总被引:2,自引:0,他引:2
A directional power-based admission control (AC) scheme is proposed for base stations deploying beamforming antenna arrays. The proposed AC algorithm is a natural extension of the conventional power based AC scheme for cells using standard sector antennas. The directional scheme takes the load per beam/direction into account in the AC decision, so the cell load is controlled in accordance with the spatial filtering gain provided by using beamforming antenna arrays. The scheme is tested by means of Monte Carlo simulations in a multicell wideband code division multiple access (WCDMA) network, where users with different bit rates are present. The obtained results demonstrate that the directional power based AC scheme allows a higher traffic load in cells using beamforming antenna arrays without jeopardizing the stability of the network. Application of a four element antenna array is found to provide a capacity gain of a factor 2.7 for a network with many low bit rate users, while the gain is reduced to a factor 2.3 for traffic scenarios with a mixture of high and low bit rate users. 相似文献
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提出了用分布于 x?y?z 三轴上的三个阵元估计扩频信号各条多径的来波方向(DOA)的方法,以及用由 x?y 均匀平面圆阵和 z 轴直线阵组成的阵列天线形成 3 维波束的方法。根据 CDMA 信号模型和多径信道模型,用 最大似然(ML)法分别估计出信号到达 3 个阵元的复信道响应,并利用复信道响应的幅角来估计各条多径信号 的 DOA;然后在已有最小均方误差(MMSE)法和最小二乘(LS)法的基础上生成带限制条件的扩展 MMSE(EMMSE)法形成 3 维波束。模拟表明,给出的 DOA 估计方法具有很高的精度,而 EMMSE 方法形成的波束主 瓣窄,旁瓣被抑制,有很高的输出信干噪比。 相似文献