In order to investigate the impact of channel model parameters on the channel capacity of a multipleinput multiple-output （MIMO） system, a novel method is proposed to explore the channel capacity under Rayleigh fiat...In order to investigate the impact of channel model parameters on the channel capacity of a multipleinput multiple-output （MIMO） system, a novel method is proposed to explore the channel capacity under Rayleigh fiat fading with correlated transmit and receive antennas. The optimal transmitting direction which can achieve maximum channel capacity is derived using random matrices theory. In addition, the closed-form expression for the channel capacity of MIMO systems is given by utilizing the properties of Wishart distribution when SNR is high. Computer simulation results show that the channel capacity is maximized when the antenna spacing increases to a certain point, and furthermore, the larger the scattering angle is, the more quickly the channel capacity converges to its maximum. At high SNR （〉12 dB）, the estimation of capacity is close to its true wlue. And, when the same array configuration is adopted both at the transmitter and the receiver, the UCA yields higher channel capacity than ULA.展开更多
[目的]“驱动力-压力-状态-影响-响应”(driving force-pressure-state-impact-response,DPSIR)模型被广泛应用于可持续发展、水土资源及环境管理科学等多个领域,成为评价社会经济与生态环境协调发展程度的有效工具.然而,很少有指标能...[目的]“驱动力-压力-状态-影响-响应”(driving force-pressure-state-impact-response,DPSIR)模型被广泛应用于可持续发展、水土资源及环境管理科学等多个领域,成为评价社会经济与生态环境协调发展程度的有效工具.然而,很少有指标能够反映当地有关部门对水资源的调蓄能力,尤其在一些水资源水质和水量分布差异过大的地区,为此需要对模型的响应层指标进行优化.[方法]在指标选取和权重计算过程中,针对研究区的特点,在响应层中加入了大中型水库供水覆盖范围的指标,用以反映当地有关部门对于水资源的调蓄能力;同时,在对大中型水库供水覆盖范围的评价中,综合考虑水平维度和垂直维度两方面的因素.[结果]利用地理信息系统(Geographic Information System,GIS)技术,在DPSIR模型中将水平维度和垂直维度两方面的评价结果相结合,使得大中型水库供水覆盖范围的最终评价结果与实际情况更加贴合,从而使得最终的评价结果能够更加精准地反映研究区岩溶水资源的承载力情况.[结论]大中型水库供水覆盖范围指标的引入以及评价方法很好地反映了水资源的调蓄能力,一定程度上完善了当前的水资源评价体系.展开更多
基金the National Natural Science Foundation of China (60372055) and the National DoctoralFoundation of China (2003698027).
文摘In order to investigate the impact of channel model parameters on the channel capacity of a multipleinput multiple-output （MIMO） system, a novel method is proposed to explore the channel capacity under Rayleigh fiat fading with correlated transmit and receive antennas. The optimal transmitting direction which can achieve maximum channel capacity is derived using random matrices theory. In addition, the closed-form expression for the channel capacity of MIMO systems is given by utilizing the properties of Wishart distribution when SNR is high. Computer simulation results show that the channel capacity is maximized when the antenna spacing increases to a certain point, and furthermore, the larger the scattering angle is, the more quickly the channel capacity converges to its maximum. At high SNR （〉12 dB）, the estimation of capacity is close to its true wlue. And, when the same array configuration is adopted both at the transmitter and the receiver, the UCA yields higher channel capacity than ULA.
文摘[目的]“驱动力-压力-状态-影响-响应”(driving force-pressure-state-impact-response,DPSIR)模型被广泛应用于可持续发展、水土资源及环境管理科学等多个领域,成为评价社会经济与生态环境协调发展程度的有效工具.然而,很少有指标能够反映当地有关部门对水资源的调蓄能力,尤其在一些水资源水质和水量分布差异过大的地区,为此需要对模型的响应层指标进行优化.[方法]在指标选取和权重计算过程中,针对研究区的特点,在响应层中加入了大中型水库供水覆盖范围的指标,用以反映当地有关部门对于水资源的调蓄能力;同时,在对大中型水库供水覆盖范围的评价中,综合考虑水平维度和垂直维度两方面的因素.[结果]利用地理信息系统(Geographic Information System,GIS)技术,在DPSIR模型中将水平维度和垂直维度两方面的评价结果相结合,使得大中型水库供水覆盖范围的最终评价结果与实际情况更加贴合,从而使得最终的评价结果能够更加精准地反映研究区岩溶水资源的承载力情况.[结论]大中型水库供水覆盖范围指标的引入以及评价方法很好地反映了水资源的调蓄能力,一定程度上完善了当前的水资源评价体系.
