Antenna array gain is a relative measure of performance defined differently in various literature. Most definitions of gain are not power consistent, and thus cannot be used directly in link budget analysis. In this s...Antenna array gain is a relative measure of performance defined differently in various literature. Most definitions of gain are not power consistent, and thus cannot be used directly in link budget analysis. In this short paper, we present a power correction factor for common definitions of power gain of antenna arrays that allows them to be used in standard link budget calculations.展开更多
In this paper we used the probability distribution of the average channel gain of the fading channel to analyze the degree of fading effects on both the PER (packet error rate) and the throughput in OFDM systems. Inst...In this paper we used the probability distribution of the average channel gain of the fading channel to analyze the degree of fading effects on both the PER (packet error rate) and the throughput in OFDM systems. Instead of solely examining the average received SNR (signal-to-noise ratio) value of a packet, considering the whole distribution of the average received SNR allows us to aggregate a better selection of the mode switching thresholds in the rate adaptive 802.11 a/g WLAN. This paper demonstrates that the set of mode switching thresholds can be determined for each individual target , so that the optimal throughput performance is obtained on a per target basis. Numerical results show that mode switching thresholds should be reduced with the lowering of target values. This conclusion could have significant implications for improving the performances of location (distance)-dependent mobile applications, since the determinations of target values are closely related to the distances between mobile devices and the access point.展开更多
分析了光纤承载无线(RoF,Radio over Fiber)外调制链路的噪声系数。通过建立数学模型,从小信号模型下推导出外部调制链路的增益和噪声系数的表达式,并研究了影响链路噪声系数的各种因素,如调制器的半波电压,输入光功率,光纤损耗,检测器...分析了光纤承载无线(RoF,Radio over Fiber)外调制链路的噪声系数。通过建立数学模型,从小信号模型下推导出外部调制链路的增益和噪声系数的表达式,并研究了影响链路噪声系数的各种因素,如调制器的半波电压,输入光功率,光纤损耗,检测器的效率等,理论上得出降低噪声系数的一般方法和结论,即可以适当的降低调制器的半波偏置电压,提高激光器的输入光功率,可以选用低损耗光纤以及提高检测器的斜度效率等。展开更多
文摘Antenna array gain is a relative measure of performance defined differently in various literature. Most definitions of gain are not power consistent, and thus cannot be used directly in link budget analysis. In this short paper, we present a power correction factor for common definitions of power gain of antenna arrays that allows them to be used in standard link budget calculations.
文摘In this paper we used the probability distribution of the average channel gain of the fading channel to analyze the degree of fading effects on both the PER (packet error rate) and the throughput in OFDM systems. Instead of solely examining the average received SNR (signal-to-noise ratio) value of a packet, considering the whole distribution of the average received SNR allows us to aggregate a better selection of the mode switching thresholds in the rate adaptive 802.11 a/g WLAN. This paper demonstrates that the set of mode switching thresholds can be determined for each individual target , so that the optimal throughput performance is obtained on a per target basis. Numerical results show that mode switching thresholds should be reduced with the lowering of target values. This conclusion could have significant implications for improving the performances of location (distance)-dependent mobile applications, since the determinations of target values are closely related to the distances between mobile devices and the access point.
文摘分析了光纤承载无线(RoF,Radio over Fiber)外调制链路的噪声系数。通过建立数学模型,从小信号模型下推导出外部调制链路的增益和噪声系数的表达式,并研究了影响链路噪声系数的各种因素,如调制器的半波电压,输入光功率,光纤损耗,检测器的效率等,理论上得出降低噪声系数的一般方法和结论,即可以适当的降低调制器的半波偏置电压,提高激光器的输入光功率,可以选用低损耗光纤以及提高检测器的斜度效率等。
基金The National Natural Science Foundation of China(Nos.61172051,61302070,61302071,61302072)the Fundamental Research Funds for the Central Universities(Nos.N110204001,N120804002,N110604008)+3 种基金the Specialized Research Fund for the Doctoral Program of Higher Education(No.20110042110023)the Liaoning Province PhD Start-up Fund(No.20131029)The Science and Technology Research Project of Chongqing Municipal Education Commission(No.KJ120523)the Natural Science Foundation Project of CQ CSTC(No.cstc2011jjA40036)
