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QPSK调制方式下瑞利信道发端分集的性能分析及实现
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作者 余建峰 赵姚同 《信息技术》 2005年第4期49-51,共3页
在QPSK调制方式下对瑞利信道的采用Alamouti方法的发端分集和采用MRC方法的收端分集误码性能进行分析比较,并用MATLAB对发端、收端分集技术进行模拟,说明发端分集技术可以取得和收端分集技术相当的性能,并介绍几种简化的发端分集技术。
关键词 RAYLEIGH信道 空间分集 最大比合并 Mamouti模型
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Rain Attenuation Effects on 2.6 GHz WiMAX Networks Deployment in Ghana
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作者 Patrick Fiati 《World Journal of Engineering and Technology》 2015年第3期83-90,共8页
WiMAX communication systems operating at 2.6 G frequencies are used for broadband multimedia and internet based services. At these frequencies, the signal will be affected by various propagation impairments such as ra... WiMAX communication systems operating at 2.6 G frequencies are used for broadband multimedia and internet based services. At these frequencies, the signal will be affected by various propagation impairments such as rain attenuation, cloud attenuation, tropospheric scintillation, ionospheric scintillation, water vapour attenuation, and rain and ice depolarization. Among all the pro-pagation impairments, rain attenuation is the most important and critical parameter. In this research, rain attenuation is calculated at KNUST, Kumasi using ITU-R rain attenuation model. The preliminary results of the work will be used to calculate the attenuation experimentally and comparison can be made, which helps to develop a new rain attenuation model at 2.6 G bands. Rain attenuation is an important aspect of signal propagation above 2.6 GHz frequency. The attenuation time series generation from point rain rate measurement is crucial due to unavailability of actual signal measurements. In this research, a simple and realistic approach has been demonstrated for better estimation of rain attenuation using WiMAX-band signal propagation data and ground rain rate measurements in Ghana. The ITU-R model of rain attenuation has been modified by incorporating an effective slant path model. The effective slant path has been estimated and modeled in terms of a power-law relationship of rain rate data of 2007-2008. The methodology has been validated with the measured data of 2014. Comparison with ITU-R and GMET clearly demonstrates the improved predictability of the proposed model at the present tropical location. 展开更多
关键词 RAIN Attenuation ITU-R model RAIN FALL Rate WIMAX alamouti
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