The traditional geometrical depolarization model that single transmitter to single receiver provides a simple method of polarization channel modeling. It can obtain the geometrical depolarization effect of each path i...The traditional geometrical depolarization model that single transmitter to single receiver provides a simple method of polarization channel modeling. It can obtain the geometrical depolarization effect of each path if known the antenna configuration, the polarization field radiation pattern and the spatial distribution of scatters. With the development of communication technology, information transmission spectrum is more and more scarce. The original model provides only a single channel polarization state, so the information will be limited that the polarization state carries in the polarization modulation. The research is so significance that how to carries polarization modulation information by using multi-antenna polarization state. However, the present study shows that have no depolarization effect model for multi-antenna systems. In this paper, we propose a multi-antenna geometrical depolarization model. On the basis of a single antenna to calculate the depolarization effect of the model, and through simulation to analysis the main factors that influence the depolarization effect. This article provides a multi-antenna geometrical depolarization channel modeling that can applied to large-scale array antenna, and to some extent increase the speed of information transmission.展开更多
Massive MIMO is one of tile enabling technologies tbr beyond 4G and 5G systems due to its ability to provide beamforming gain and reduce interference Dual-polarized antenna is widely adopted to accommodate a large num...Massive MIMO is one of tile enabling technologies tbr beyond 4G and 5G systems due to its ability to provide beamforming gain and reduce interference Dual-polarized antenna is widely adopted to accommodate a large number of antenna elements in limited space. However, current CSI（channel state information） feedback schemes developed in LTE for conventional MIMO systems are not efficient enough for massive MIMO systems since the overhead increases almost linearly with the number of antenna. Moreover, the codebook for massive MIMO will be huge and difficult to design with the LTE methodology. This paper proposes a novel CSI feedback scheme named layered Multi-paths Information based CSI Feedback （LMPIF）, which can achieve higher spectrum efficiency for dual-polarized antenna system with low feedback overhead. The MIMO channel is decomposed into long term components （multipath directions and amplitudes） and short term components （multipath phases）. The relationship between the two components and the optimal precoder is derived in closed form. To reduce the overhead, different granularities in feedback time have been applied for the long term components and short term components Link and system level simulation results prove that LMPIF can improve performance considerably with low CSI feedback overhead.展开更多
Chitosan-iron nanowires in porous anodic alumina （PAA） have been successfully prepared under ambient conditions as an ad- sorbent. The adsorbent was characterized by scanning electron microscopy, X-ray photoelectron...Chitosan-iron nanowires in porous anodic alumina （PAA） have been successfully prepared under ambient conditions as an ad- sorbent. The adsorbent was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and N2-BET surface area. The results showed that PAA can disperse and protect Fe0 nanorods from oxidation. The adsorption characteris- tics of trace Cr（VI） onto adsorbent have been examined at different initial Cr（VI） concentrations with pH 5. Batch adsorption studies show that the removal percentage of adsorbent for the removal of trace Cr（VI） is strongly dependent on the initial Cr（VI） concentrations. Langmuir and Freundlich isotherm models were used to analyze the experiment data. The adsorption of trace Cr（VI） by adsorbent is well modeled by the Langmuir isotherm and the maximum adsorption capacity of Cr（VI） is calcu- lated as 123.95 mg/g which is very closed to the experiment results. Intraparticle diffusion study shows that the intraparticle diffusion of adsorbent is not the sole rate-controlling step. The negative value of Gibbs free energy change,△G0, indicated that the process of Cr（VI） onto adsorbent was spontaneous. This work has demonstrated that chitosan-iron nanowires in porous anodic alumina as an adsorbent has promising potential for heavy metal removal at trace level.展开更多
基金supported in part by the National Natural Science Foundation of China(61561039,61461044)the Natural Science Foundation of Ningxia(NZ14045)the Higher School Science and Technology Research Project of Ningxia(NGY2014051)
文摘The traditional geometrical depolarization model that single transmitter to single receiver provides a simple method of polarization channel modeling. It can obtain the geometrical depolarization effect of each path if known the antenna configuration, the polarization field radiation pattern and the spatial distribution of scatters. With the development of communication technology, information transmission spectrum is more and more scarce. The original model provides only a single channel polarization state, so the information will be limited that the polarization state carries in the polarization modulation. The research is so significance that how to carries polarization modulation information by using multi-antenna polarization state. However, the present study shows that have no depolarization effect model for multi-antenna systems. In this paper, we propose a multi-antenna geometrical depolarization model. On the basis of a single antenna to calculate the depolarization effect of the model, and through simulation to analysis the main factors that influence the depolarization effect. This article provides a multi-antenna geometrical depolarization channel modeling that can applied to large-scale array antenna, and to some extent increase the speed of information transmission.
基金supported by the National High-Tech R&D Program(863 Program 2015AA01A705)
文摘Massive MIMO is one of tile enabling technologies tbr beyond 4G and 5G systems due to its ability to provide beamforming gain and reduce interference Dual-polarized antenna is widely adopted to accommodate a large number of antenna elements in limited space. However, current CSI（channel state information） feedback schemes developed in LTE for conventional MIMO systems are not efficient enough for massive MIMO systems since the overhead increases almost linearly with the number of antenna. Moreover, the codebook for massive MIMO will be huge and difficult to design with the LTE methodology. This paper proposes a novel CSI feedback scheme named layered Multi-paths Information based CSI Feedback （LMPIF）, which can achieve higher spectrum efficiency for dual-polarized antenna system with low feedback overhead. The MIMO channel is decomposed into long term components （multipath directions and amplitudes） and short term components （multipath phases）. The relationship between the two components and the optimal precoder is derived in closed form. To reduce the overhead, different granularities in feedback time have been applied for the long term components and short term components Link and system level simulation results prove that LMPIF can improve performance considerably with low CSI feedback overhead.
基金supported by China Textile Industry Association Guide Science and Technology Project (2013039)the National Natural Science Foundation of China (51375351)
文摘Chitosan-iron nanowires in porous anodic alumina （PAA） have been successfully prepared under ambient conditions as an ad- sorbent. The adsorbent was characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and N2-BET surface area. The results showed that PAA can disperse and protect Fe0 nanorods from oxidation. The adsorption characteris- tics of trace Cr（VI） onto adsorbent have been examined at different initial Cr（VI） concentrations with pH 5. Batch adsorption studies show that the removal percentage of adsorbent for the removal of trace Cr（VI） is strongly dependent on the initial Cr（VI） concentrations. Langmuir and Freundlich isotherm models were used to analyze the experiment data. The adsorption of trace Cr（VI） by adsorbent is well modeled by the Langmuir isotherm and the maximum adsorption capacity of Cr（VI） is calcu- lated as 123.95 mg/g which is very closed to the experiment results. Intraparticle diffusion study shows that the intraparticle diffusion of adsorbent is not the sole rate-controlling step. The negative value of Gibbs free energy change,△G0, indicated that the process of Cr（VI） onto adsorbent was spontaneous. This work has demonstrated that chitosan-iron nanowires in porous anodic alumina as an adsorbent has promising potential for heavy metal removal at trace level.
