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分布式天线系统MIMO信道容量分析 总被引:11,自引:1,他引:10
结合了分布式天线系统和MIMO信道特点的分布式MIMO系统可以改善覆盖特性,提高系统容量。提出了包含路径损耗、快衰落和阴影衰落的两层分集分布式MIMO系统。对MIMO信道容量的分析表明,分布式MIMO系统具有良好的信道容量均匀覆盖特性。与传统集中式天线系统相比,分布式MIMO系统可以获得更好的小区平均信道容量。对下行信道容量的数值分析表明,由于“充水”方式功率分配可以充分利用MIMO信道信息,此时的分布式MIMO系统可以比等功率分配条件下的分布式天线系统多获得0.25bit/(s·Hz)每发送天线的信道容量增量。 相似文献
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通过天线选择可以提高多输入多输出(MIMO)系统的容量,并能有效地降低MIMO系统的复杂度和射频成本.基于连续选择使MIMO系统容量增加最大的天线的方法,用矩阵及行列式运算导出了一种新的接收天线选择算法.将该算法用于分布式MIMO系统的容量研究,通过计算机仿真,结合Rice因子K及不同视距传播条件等因素对分布式MIMO系统上行信道容量的影响进行了研究.仿真结果在分布式无线通信组网及网络优化中具有指导意义. 相似文献
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利用多输入多输出(MIMO)系统中的发射端天线选择算法,可以在降低复杂度的同时,有效地提高系统性能。考虑到基于线性接收机的空间复用系统,在通过已选择的发射天线上采用等功率分配等增益传输可以减少反馈信息量。因此,文章提出了空间相关衰落信道下可提升系统容量的统计多模发射天线选择方法。 相似文献
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针对分布式MIMO系统的圆形小区平均遍历容量展开研究.文章首先建立了包含快衰落、阴影衰落和路径损耗的复合衰落信道模型;然后,对分布式天线采用覆盖式(BT)传输策略,并在高信噪比条件下,导出给定移动台位置时,区上、下行点对点链路遍历容量表达式.最后,考虑移动台在小区内任意分布特点,进一步推导出小区平均遍历容量闭合近似表达式.仿真结果表明,所推导的近似表达式可很好的反应系统的实际性能.导的近似表达式可很好的反应系统的实际性能. 相似文献
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针对Nakagami/lognormal复合衰落信道,研究了层叠分布式天线系统(Cascade Distributed Antenna System-CDAS)在CDMA网络中的平均误符号率性能.推导出了采用混合SC/MRC分集接收机的层叠分布式天线系统平均误符号率性能公式.利用推导出的平均误符号率表达式,分析了多径密度函数(Multipath Intensity Profile-MIP)衰减因子、空时分集维数、活动用户数以及阴影衰落因子对平均误符号率性能的影响.仿真表明层叠分布式天线系统可以有效对抗衰落,提高系统容量以及削弱对数正态阴影衰落的影响. 相似文献
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基于天线选择的低秩信道MIMO系统容量研究 总被引:1,自引:0,他引:1
最近的研究表明,在衰落信道多天线MIMO系统的容量随发射天线数线性增加.而对于低散射环境,即使信号经历独立的衰落,信道秩的降低也会严重影响系统容量的增加.对于这种低秩环境,选择天线发射或接收可以有效地降低系统的成本.本文研究了天线选择对低秩信道MIMO系统容量的影响.仿真结果表明,对不同的信道条件,适当选择天线发射不仅可以增加信道容量,而且可以降低系统的复杂度和射频成本.适当选择天线接收,在不严重降低系统容量的前提下,也达到了降低系统成本的目的. 相似文献
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几种多天线系统的信道容量比较 总被引:3,自引:1,他引:2
分布式天线、智能天线和扇区天线是三种能大大提高无线通信系统容量的技术,本文比较了这三种多天线系统的信道(Shannon)容量.假设每个用户在所有接收天线上的总功率相等,分析表明分布式天线和扇区天线的信道容量远大于智能天线的信道容量,而传统的观点认为智能天线在抑制干扰时要比扇区天线的性能更好,从而获得更大的系统容量.另外我们分析了分布式天线在渐近条件下的信道容量,即用户数K和载波数M都趋近无穷大,而保证α=K/M一定.分析表明在α较大时,分布式天线与比扇区天线的信道容量差趋近常数0.44比特/秒/维,但是如果考虑分布式天线的分集增益,那么分布式天线的信道容量要远大于扇区天线. 相似文献
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Performance Analysis of a Sectorized Distributed Antenna System with Reduced Co-Channel Interference 总被引:1,自引:1,他引:0
LIU Chen WANG Wen-boWireless Signal Processing Networks Laboratory Beijing University of Posts Telecommunications Beijing P. R. China 《中国邮电高校学报(英文版)》2006,13(1):20-24
1IntroductionThe next generation mobile communication systemissupposedto provide high data rate services such as Inter-net access and multi media applications whichare morelikelyto be affected by Inter-Symbol-Interference(ISI)inwireless multi-path fading … 相似文献
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Yuehui Ouyang Love D.J. Chappell W.J. 《Vehicular Technology, IEEE Transactions on》2009,58(4):1752-1765
In this paper, we analyze the performance of novel wearable multiple-input-multiple-output (MIMO) systems, which consist of multiple electrotextile wearable antennas distributed at different locations on human clothing. For wearable applications, a semidirectional radiation pattern of the wearable patch antenna is preferred over an omnidirectional radiation of conventional dipole antennas to avoid unnecessary radiation exposure to the human body and radiation losses. Additionally, the spatial distribution of the antennas is not constrained as a typical handheld unit. Through theoretical modeling and simulation, the wearable MIMO system is shown to demonstrate a significantly higher channel capacity than a conventional system on a handheld platform (e.g., a compact dipole array or a single dipole), due to enhanced spatial diversity and antenna pattern diversity. The unique effects of antenna directivity and location on the MIMO system capacity are investigated in terms of antenna correlation and effective gain under different wireless channel models. The advantage of a wearable system over a conventional system was further confirmed by detailed physical modeling through the combination of full-wave electromagnetic and ray-tracing simulations. Finally, complex channel response matrices were measured to characterize the performance of a body-worn MIMO system in comparison with a reference full-size dipole antenna. The 319% improvement in 10% outage capacity for the body-worn system over the reference system made of a full-size dipole antenna is consistent with the 288% improvement projected by theoretical modeling and the average 300% improvement found in the physical simulation of two typical indoor scenarios. 相似文献
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The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore
to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division
Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the
detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support
high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to
compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide
the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement
campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters,
as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput,
and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly
show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to
radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system.
However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show
that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems. 相似文献
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Multiple-input-multiple-output (MIMO) wireless systems use multiple antenna elements at transmit and receive to offer improved capacity over single antenna topologies in multipath channels. In such systems, the antenna properties as well as the multipath channel characteristics play a key role in determining communication performance. This paper reviews recent research findings concerning antennas and propagation in MIMO systems. Issues considered include channel capacity computation, channel measurement and modeling approaches, and the impact of antenna element properties and array configuration on system performance. Throughout the discussion, outstanding research questions in these areas are highlighted. 相似文献
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X. Zhou P. Kyritsi J. Martinez A. Adenet C. Lemasson P. C. F. Eggers 《Wireless Personal Communications》2007,43(2):759-776
The purpose of this paper is to investigate the performance of Time Reversal (TR) for short-range Multiple-Input Single-Output
(MISO) systems in the Industrial, Scientific, and Medical (ISM) 5 GHz band using actual channel measurements. Such a scenario
is considered for low cost user equipment applications, where low-complexity schemes like TR will be an potential candidate.
The experiment is conducted with 8 transmit antennas and 1 receive antenna per user. The antennas are arranged in compact
and distributed configurations, and the channel is measured in both Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) dominated
scenarios. We investigate the performance of TR in terms of time compression, spatial focusing, and diversity gain, by analyzing
the delay spread, the spatial Peak-to-Average-Leakage power ratio and the diversity gain, respectively. The conclusions that
can be drawn from the experiment are: TR with multiple transmit antennas shows better performance compared to the single antenna
link in terms of time compres- sion, spatial focusing, and diversity gain, even in realistic short-range communications. Second,
a distributed 8 Tx antenna configuration achieves lower delay spread and higher diversity gain than a compact antenna array
with the same number of elements. In the situation where practical impairments are taken into consideration, the system delay
involving propagation and processing time is found to be a crucial parameter degrading the performance of TR. 相似文献
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A radio access system with distributed antennas 总被引:19,自引:0,他引:19
This paper analyzes a radio access system that has multiple antennas spatially distributed throughout each cell, instead of a single antenna at each cell. The same signal is simulcast by each antenna in the cell. The signals at a given cell could be multiplexed and modulated for radio transmission at a single node, then transmitted on a coaxial cable distribution system to and from the distributed antennas in a cell. Frequency translation and radio frequency (RF) amplification may need to be performed at each antenna, except for indoor applications with short coaxial cables. This paper presents calculations of signal-to-interference ratios (SIR) and handoff performance for cells with distributed antennas. It is shown that the use of distributed antennas can substantially increase the SIR above a system with a single antenna per cell, and this increase is quantified. It is also shown that increasing the number of antennas results in better overall handoff performance, with a lower number of handoffs and higher received signal power. Minimizing the number of handoffs will reduce the impact of wireless services on network elements 相似文献
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为了抑制多用户分布式多入多出(MIMO)系统中的同道干扰(CCI),使系统同时服务于更多用户,提出一种发送天线选择与预编码的联合设计方法。该方法立足于分布式MIMO系统基站端天线较多的特点,将下行发送天线选择与信漏噪比(SLNR)预编码相结合,通过为用户选择不同天线,从根本上减少CCI;在为每个用户选择天线时,先以信道子矩阵的迹为依据进行端口选择,再采用逐减的方法选择使SLNR损失值最小的天线,以保证每个用户对其他用户的干扰尽量小,从而达到进一步抑制CCI的目的。复杂度分析和仿真结果表明,该方法在具有较低复杂度同时,其容量性能仍可逼近最优算法;较之单纯的SLNR预编码,在相同的容量性能约束下,其能够有效增加系统同时服务的用户数。 相似文献
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The analytical upper bound and lower bound on the ergodic capacity of polarized distributed antenna system and their relation with antenna polarization on Rician channel are deduced by applying properties of complex non-central Wishart matrices and matrix-variate non-central quadratic forms. Compared to the related studies, our analysis is extended to account for the polarized distributed system with Rician fading where a line-of-sight component exists and both ends are affected by spatial correlation. The antenna polarization has some impacts on the capacity bounds according to the expressions of capacity bounds. Both the transmitter and the receiver are equipped with multiple polarization antennas, and the transmitters are of linear layout. A power allocation scheme based on the path loss fading is presented by maximizing the capacity upper bound. The power allocation scheme is feedback efficient compared with those power allocation schemes based on statistical parameters of the channel which need a large amount of feedback. In the simulations, the ergodic capacity of polarized distributed MIMO is analyzed. Comparisons are taken on the effects of angle spread, Rician factor and power on the ergodic capacity. The proposed power allocation scheme is superior to the equal power allocation scheme and has very close performance to the optimal power allocation scheme. 相似文献