共查询到20条相似文献,搜索用时 0 毫秒
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在大型数字相控阵系统中,为了满足阵列增益及天线方向图特性,需要保证阵列通道的幅度和相位的一致性,而动态不一致性标校是大型阵列的标校难题。提出了一种基于直接数字频率合成(Direct Digital Synthesizer,DDS)相位搜索算法的数字相控阵通道一致性标校技术,较传统基于相关算法的标校技术,可有效降低对标校信号信噪比的要求,且可提升大规模数字阵列通道标校的效率。仿真结果表明,当信噪比等于0 dB时,采用所提算法可将幅度估计误差的均方根误差(Root Mean Square Error,RMSE)值控制在0.3 dB以内,相位估计误差的RMSE值可控制在1.5°以内,较传统算法的性能均提升了3倍。通过搭建样机评估系统,进一步验证了提出算法对数字相控阵通道一致性标校性能的提升。 相似文献
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大时带积线性调频信号源幅相误差分析与校正 总被引:1,自引:1,他引:1
针对产生LFM信号的数字方法,分析了系统的幅相误差来源,并根据误差频率对其进行了分类。提出了一种将正交调制LFM信号产生系统的幅相误差映射到基带后,在数字域利用复系数FIR滤波器进行校正的方案。针对直接数字波形合成LFM信号产生系统,将误差校正方法简化为直接对存储的数字波形进行预失真处理。最后将校正方法应用于实际系统,结果表明提出的幅相误差校正方案易行、有效,能明显提高输出LFM信号的性能。 相似文献
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雷达通信一体化系统是缓解无线电频谱拥塞和频谱资源短缺的高效解决方案。在雷达的最小信号噪声比和最小通信传输速率的约束条件下,通过构建混合整数非线性优化模型,提出了子载波和功率联合分配方法,实现系统总发射功率的最小化。首先将优化模型转化为线性模型并添加罚因子,然后选择用于雷达或通信目的的子载波。考虑到雷达性能和通信性能评价标准的差异,对用于雷达或通信目的子载波设置不同的发射功率约束,最终通过循环优化实现子载波和功率的联合分配。数值仿真结果表明,所提方法显著节约了功率资源。 相似文献
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Shuaijun Liu Yuanyuan Fan Yuemei Hu Dapeng Wang Lixiang Liu Longfei Gao 《International Journal of Satellite Communications and Networking》2020,38(1):74-83
Dynamic power allocation is the key technology to maintain the link quality and improve the system throughput in multibeam satellite systems. Many numerical optimization algorithms have been proposed to optimize the power allocation schemes among beams. However, current metaheuristic algorithms, most of which are off‐line iterative methods, are not appropriate in nonuniform traffic demands and time‐varying channels due to the high computational complexity. To solve this problem, an assignment game–based dynamic power allocation (AG‐DPA) is proposed to achieve the suboptimality with low complexity in multibeam satellite systems. The key idea of the proposed AG‐DPA is to model the DPA problem into an assignment game model where the competitive equilibrium is achieved. Further, an adaptive price factor is introduced to make a trade‐off between algorithm performance and complexity. Simulation results show the effectiveness of the proposed AG‐DPA algorithm. 相似文献
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为了提高热电偶动态校准的准确性,采用半导体激光器、红外探测器和被校准热电偶组成新的热电偶动态校准系统,分析了动态校准中红外探测器静态校准目的。根据反向传播神经网络原理,确定了反向传播神经网络的结构和参量,同时针对普通K型铠装热电偶进行了动态校准实验,得到红外探测器静态校准数据,由此数据采用最小二乘法和反向传播神经网络分别进行数据的非线性拟合,对两种方法的拟合结果进行了分析,并给出了拟合曲线。结果表明,在样本数据少、分布不均匀的情况下,反向传播神经网络拟合效果优于传统的最小二乘法,减小了由于数据拟合所带来的误差,能够更加准确地获得热电偶动态特性,实现热电偶动态补偿。这一研究结果对于热电偶动态特性研究具有重要的参考价值。 相似文献
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This paper introduces an transmit power allocation (TPA) algorithm considering dynamic channel allocation (DCA) for a reuse-partitioning-
based Orthogonal frequency division multiple access (OFDMA)/FDD cellular system. The proposed reuse partitioning-based DCA
algorithm guarantees quality of service (QoS) by considering fairness among mobile stations in an OFDMA/FDD system. However,
to improve the SINR values for users around the cell edge and increase the overall system throughput compared with the conventional
OFDMA/FDD system of frequency reuse factor (FRF) 1, an effective TPA algorithm is also combined with the proposed DCA to adjust
the transmit power per user according to the average received SINR value. Simulation results show that the proposed DCA algorithm
increases the sector throughput by about 25% when compared with the conventional case that do not apply the proposed DCA algorithm.
When the proposed TPA is combined with the proposed DCA algorithm, a further increase in the sector throughput of about 6%
is achieved than when using just the proposed DCA algorithm. 相似文献
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Cooperative diversity is a new technology to improve bit error rate(BER)performance in wireless communications.A new power allocation algorithm to improve BER performance in cellular uplink has been proposed in this paper.Some existing power allocation schemes were proposed for the purpose of maximizing the channel capacity or minimizing the outage probability.Different from these schemes,the proposed algorithm aims at minimizing the BER of the systems under the constraint of total transmission power.Besides this characteristic,the proposed algorithm can realize a low complexity real-time power allocation according to the fluctuation of channels.Simulation results show that the proposed algorithm can decrease the BER performance of the systems effectively. 相似文献
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多通道接收机幅相校准测试系统的设计 总被引:1,自引:1,他引:0
在多通道宽带雷达接收机中,通道内I/Q支路、通道之间的幅相均衡是接收系统的关键指标。文中介绍了某接收系统的校正原理,并基于GPIB总线接口,采用智能仪表组建了幅相校准测试系统,实现接收机幅相一致性参数自动测量,解决了测试参数多、测试量大的问题,并通过幅相调节网络补偿各通道的幅度和相位,提高接收系统的幅相一致性水平。 相似文献
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OFDM双向多跳网络的新型比特和功率分配算法 总被引:1,自引:0,他引:1
结合新型双向多跳网络协议和正交频分复用技术,研究旨在保证通信质量情况下的自适应比特和功率分配算法,其目的是以较小发送功率和较高频谱效率完成通信。通过凸优化理论推导出最优功率分配算法,并提出一种基于贪婪原则的自适应比特分配算法,能够以较低的复杂度在实际工程中完成部署。仿真分析表明,提出的双向多跳算法是传统多跳协议频谱效率的2倍,所需发送功率是平均资源分配算法的1/3。 相似文献
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By using spectrum allocation technology of cognitive radio into integrated satellite and terrestrial networks,the satellite communication network can share spectrum with the terrestrial network and improve utilization efficiency of frequency spectrum in the satellite communication system.Firstly,a spectrum resource sharing model in integrated satellite and terrestrial networks was introduced,and the scenery that cognitive satellite downlinks use the vacant spectrum of terrestrial network was analyzed.Then,the interference and signal model was analyzed.Finally,considering different priority types of satellite terrestrial terminals,a spectrum allocation scheme based on priority was proposed,which could ensure the total throughput in satellite downlink communication and increase the throughput of high-priority terrestrial terminals. 相似文献
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在慢衰落信道中,协作分集是一种新的空间分集方式。为提高协作通信系统的性能,提出以最小化系统中断概率为目标的功率分配方案。综合考虑所有路径的信道噪声功率,运用注水原理,提出在接收端最大比合并下的最佳功率分配方案。该方案计算简单,且仅需已知各个中继节点的平均信道状态信息,无需在传输中实时更新,因而不增加系统的额外开销。仿真结果表明,该方案与等功率分配方案相比,能显著降低系统的中断概率。 相似文献
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