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1.
光链路是无线局域网安全性的物理层解决方案,其中上行链路为便携式终端设备设计的LD发射光束对准是关键问题之一。在Windows平台上展示了一种自动对准的软硬件控制方法,利用Windows中的Direct Show函数库,对激光光斑与目标的对准情况进行视频信号采集和图像识别,为简化识别算法,以蓝色为特征颜色并以一个特定的形状来标识对准目标,以650 nm红色LD为识别导向光束。使之位于红外传输光束中心位置左右,通过识别LD红色光斑与蓝色目标并判断它们之间偏差的方位和距离,将数据输出到下位机控制的微型云台,在二维方位上校准光斑与目标的偏差,同时通过红外LD实现了发送端到接收目标的光信号传输。 相似文献
2.
作为ITU于2010年10月通过的4G标准之一,LTE-Advanced是3GPP长期演进(LTE)标准的增强版。文章给出了3GPP LTE-Advanced标准化时间表和关键性能,分析了上行链路多天线参考信号结构,描述了物理上行共享信道(PUSCH)中的MIMO、控制信道的上行链路MI-MO和上行链路多用户MIMO的工作原理,验证了上行链路多天线增强方案的系统性能。最后,文章还预测了LTE-Advanced R11中LTE-Ad-vanced上行链路多天线增强方案发展趋势。 相似文献
3.
TD-SCDMA小区承载能力研究 总被引:1,自引:1,他引:0
TD-SCDMA小区承载能力是评估TD-SCDMA网络容量的基础,本文从上行、下行两个维度计算TDSCDMA小区承载能力,结合现网业务流量上下行配比,提出上行受限是目前影响TD-SCDMA网络容量的主要瓶颈。并通过分析造成上行受限的原因,提出增强TD-SCDMA小区上行承载能力的可选方案。 相似文献
4.
The capacity and the interference statistics (mean value and variance) of the sectors of the cigar-shaped Wideband Code Division
Multiple Access microcells are studied. The two-slope propagation model is used in the analysis. A model of five microcells
is used to calculate the uplink capacity and interference statistics assuming highways cigar-shaped microcells. The capacity
and the interference statistics of the microcell are studied for different sector range, propagation exponent, antenna side
lobe levels and different standard deviation of the power control error. It is noticed that the quasi-maximum uplink sector
capacity can be got when the sector range R is between 600 and 1,200 m and the sidelobe level of the directive antenna used
in each sector is on the order of −15 dB. 相似文献
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6.
Bazil Taha-Ahmed 《Wireless Personal Communications》2008,46(2):233-246
The multi-service (combination of more than one service) capacity and interference statistics (mean and variance) of the sectors
of the street cross-shaped Wide Band Code Division Access (WCDMA) microcell are studied. A model of 21 cross-shaped microcells
is used to analyze the uplink. The two slope propagation model is used to analyze the uplink. The capacity and interference
statistics of the sectors are studied for different sector ranges, side lobe levels and power control (PC) standard deviation
errors. It is noticed that, increasing the sector range will increase the sector capacity, reducing the side lobe level will
also increase the sector capacity. Also it is noticed that, increasing the propagation exponent s
2 will increase the sector capacity, reducing the standard deviations of the shadowing parameters σ1 and σ2 will increase the sector capacity and that reducing the power control standard deviation error σc will increase the sector capacity.
相似文献
Bazil Taha-AhmedEmail: |
7.
Carlos Ribeiro M. Julia Fernández-Getino Garcia Víctor P. Gil Jiménez Atílio Gameiro Ana García Armada 《Wireless Personal Communications》2008,47(1):125-136
In this paper we propose a simple, yet flexible and efficient, channel estimator for the uplink in broadband orthogonal frequency
division multiplexing (OFDM) systems. The processing is performed in the time-domain, by extracting the Channel’s Impulse
Response (CIR) for each user from a joint training signal. In this OFDM system, the pilot sequence we advocate, where all
users share the same pilot sub-carriers, consists of one OFDM-symbol endowed with time-shifted properties per user, which
isolates each user’s CIR and is robust against multi-user interference. The feasibility of our approach is substantiated by
system simulation results obtained using BRAN-A broadband mobile wireless channel model.
相似文献
Ana García ArmadaEmail: |
8.
重点介绍如何有效地进行CDMA基站上行干扰的定位和清除,详细介绍干扰定位和清除的方法和流程,并给出复杂干扰定位和清除案例。 相似文献
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该文针对长期演进(LTE)上行单载波频分多址(SC-FDMA)多小区系统的性能受限于小区间干扰的问题,提出一种综合考虑协作调度和功率控制的方案。该方法分步执行小区间的协作调度和功率控制,首先调度各小区中的用户,在此基础上优化用户的发射功率。调度时首先估计小区间的干扰信息并分配频率资源块给每个小区内的用户,在优化用户的发射功率时,同时考虑由于用户功率改变所造成的目标小区和其他干扰小区性能的变化。进一步提出一种低复杂度功率控制方案,在优化目标小区用户的功率时,只考虑受目标小区干扰影响最大的几个小区性能的变化,其他干扰小区性能的变化则通过引入补偿因子来估计。计算机仿真验证了该文所提方法在系统吞吐量和小区边缘吞吐量方面的性能优势显著。 相似文献