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In this article,results obtained from wideband multiple-input multiple-output channel measurements at 4.9 GHz are presented.Measurements were performed in an indoor hotspot scenario with both line-of-sight and non-line-of-sight propagation conditions.Vertical polarized uniform linear arrays(ULAs)with different antenna spacing and orientation were utilized for investigating the impact of antenna configurations on the system performance.Based on measured channel impulse responses,the spatial correlation of ULA is analyzed and compared with the theoretical values calculated from the power azimuth spectrum.Following that,the eigenvalue statistics and capacity with respect to antenna spacing and orientation are given and compared.The diversity-multiplexing tradeoff(DMT)of measured channels at operational signal-to-noise ratio(SNR)is also presented.The reason why the DMT of measured channels is much lower than that of i.i.d.Rayleigh channels is specified. 相似文献
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为了明确高频段室内多输入多输出(Multiple-Input Multiple-Output,MIMO)无线信道与传统低频段的差异,采用基于矢量网络分析仪搭建的测量平台对典型室内环境下6.05 GHz频段和2.45 GHz频段MIMO无线信道进行测量和对比分析.基于300组高低频宽带MIMO信道测量数据,对比传输损耗、时延扩展、空间相关等大小尺度衰落特性.并阐明高频段无线空时信道新特性,分析新特性为系统设计带来的新问题.对比发现,6.05 GHz高频段与传统的2.45 GHz频段室内MIMO无线信道存在显著的差异.与2.45 GHz相比,6.05 GHz频段的传输损耗更大,时延扩展更严重,空间相关更低.在将低频段MIMO移动通信向高频段扩展时,这些差异要给予充分的重视. 相似文献
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Measured channel characterization results are provided for six stairwells in the 5‐GHz band, for two distinct stairwell types and two antenna polarizations. The stairwell channel is of interest for several applications, including Wi‐Fi and public safety. Although other authors have reported stairwell path loss for other frequency bands (900 MHz, 2.4, 5.8 GHz), to our knowledge, ours is the first work at 5 GHz. More significantly, we report on floor attenuation factors and delay spread, which prior work has not thoroughly addressed. We measured power delay profiles and from these estimated propagation path loss and root‐mean square delay spread (RMS‐DS). Path loss exponents were between 5.5 and 8.3, and vertically polarized monopoles yield larger path loss and path loss exponents than horizontal polarization. Mean RMS‐DS values ranged from 15 to 57 ns for link distances covering up to three flights of stairs. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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目前,大多数大规模多入多出(Multiple-Input Multiple-Output,MIMO)系统信道特性的研究都是针对理想的独立同分布瑞利信道条件,其传播环境为"适宜的",即大规模MIMO系统中各子信道是正交的.但在实际的物理信道中,其传播条件是"非适宜的",对"非适宜"条件下大规模MIMO系统信道特性的研究尤为重要.文章基于校园室外场景在6 GHz频段下进行实地无线信道测量,利用奇异值分解,探讨了真实环境中各子信道的正交性,并进行了信道容量的计算和对比.分析结果表明,随着天线数的增加,正交性明显得到提升,当发射端天线数十倍于接收天线数时,容量值提升最为明显,相比于独立同分布的瑞利信道,真实的传播环境下,各子信道并非完全正交,容量值也存在一定的差距,说明在"非适宜"条件下,大规模多天线系统性能并没有获得满增益. 相似文献
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工作在6GHz以上高频段的多输入多输出(Multi-Input-Multi-Output,MIMO)无线通信系统是下一代无线移动通信的有力竞争方案.目前,对制约无线系统性能的高频段空时无线信道特性研究仍较少见.针对这一现状,采用基于网络分析仪的信道测量平台对典型办公环境下6.0-6.4GHz MIMO无线信道特性进行测量和分析.为了明确高频段为系统设计带来的新问题,将测量得到的高频段MIMO信道特性参数与低频段对比.对比结果表明,6.2GHz频段与2.45GHz频段MIMO信道传播特性存在较大差异.在对6.0-6.4GHz室内覆盖MIMO无线通信系统进行设计和评估时,需要基于6.0-6.4GHz频段无线信道传播的新特性对系统的关键技术和方案进行调整. 相似文献
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A cluster-based analysis of propagation characteristics in MIMO relay channels based on wideband measurement 总被引:1,自引:0,他引:1
In this paper,the characteristics of clusters induced by a variety of propagation mechanisms in the link from the relay station(RS) to the mobile station(MS) are presented.Based on the results of high resolution channel parameter estimation,an automatic framework integrated with the manual intervention is utilized to perform the cluster identification and tracking.The power proportion and angular spread of clusters are investigated in both the line-of-sight(LOS) and non-line-of-sight(NLOS) scenarios.The measurement results indicate that the channel characteristics of clusters are different from the link from the base station to the MS due to the lower height of the RS antennas. 相似文献
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基于室内视距(Line-of-Sight,LOS)和非视距(Non-Line-of-Sight,NLOS)无线信道测量数据,研究了28 GHz多输入多输出(Multiple-Input Multiple-Output,MIMO)信道参数和容量特性.具体地说,分析了莱斯K因子、时延扩展、出发角和到达角的角度扩展等信道参数,研究了MIMO信道容量及空间相关性对容量的影响.结果表明:莱斯K因子、时延扩展以及角度扩展值取决于测量环境及场景;LOS条件下时延扩展的累积分布函数(Cumulative Distribution Function,CDF)曲线与正态分布拟合优于NLOS条件下的数据;MIMO天线空间相关性越大信道容量越小.本文结果可为28 GHz无线通信系统设计提供有用信息. 相似文献
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Array gain would be well exploited to improve power coverage if some powerful multipath components from different radio links can coherently combine at the receiver (Rx). Thus, in this paper, an algorithm is proposed for transmission in simulcast system, where partial channel state information (CSI) is needed. Based on measured multipath channel, performance of the proposed algorithm is evaluated. According to simulation results, the proposed algorithm outperforms the direction summation (DS) scheme and multipath antenna diversity (MAD) algorithm, with 2~4 dB advantage over the latters. Especially in line of sight (LOS) scenario, the advantage is more obvious. Besides, the proposed algorithm brings more gain with increasing number of transmit antennas without additional power. Finally, robustness of the proposed algorithm is examined with imperfect CSI. 相似文献
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入射及反弹射线法是研究MIMO信道的有效技术.基于入射及反弹射线法对室内环境中的MIMO信道电波传播特性进行研究,在不同粗糙度条件下,针对接收功率、均方根时延扩展、MI-MO系统信道容量的分布情况及其特点进行了比较分析.仿真结果与文献已知结论一致性良好. 相似文献
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近年来,由于多输入多输出(MIMO)通信系统有传输速率高等许多优点,受到人们的重视。在本文中,提出了一种MIMO信道估计的方法,利用了已知训练序列和全部的数据帧信息,通过估计值的误差对信道参数作进一步的调整,只需使用较短的训练序列即可避免陷入局部最小,从而提高了信息传输速率和信道估计的鲁棒性,提高了估计的精度,而且具有较低的计算复杂度。 相似文献
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研究适用于无线信道测量的定时偏移和信道联合估计方法.发射机发送具有循环前缀结构的导频信号段.接收机根据粗同步信号确定快速傅里叶变换的窗口起始位置.利用改进时域最小二乘信道估计和变换域滤波,获得高精度的信道估计值.对频域接收导频信号段的定时偏移进行精细估计,对定时偏移量进行滤波并累加.最后,对频域接收导频信号段进行定时偏移补偿.信道估计器、定时延迟偏移精细估计器与补偿单元三者构成迭代相干延迟锁定环路.仿真结果表明:采用迭代相干联合估计方法进行精细定时延迟估计的性能明显优于非相干方法. 相似文献
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John Airs 《Wireless Personal Communications》1996,3(4):353-363
There is a relatively large selection of results for indoor channel soundings at frequencies around 1 to 2 GHz but relatively few at the HIPERLAN frequencies of 5 and 17 GHz. This work provides some results taken at all three frequencies in order to redress this deficiency and also to compare results at these frequencies. A 20 GHz network analyser was used to perform the soundings. The analyser was capable of performing the Chirp Z transform to convert complex frequency response data to the time domain. Soundings were made in the Agency's office headquarters at Waterloo London and in their investigation facility at Whyteleafe. These two locations provided some diversity of sounding environments involving small offices, meeting rooms and large laboratories. Both buildings were of a 1930's style brick construction with some modern plaster board internal walls. Decay exponents and delay spreads are given for the test frequencies. Results show similar delay spreads at all frequencies. 相似文献