Cloud computing.based heterogeneous networks(C.Het Nets) have been considered as promising network architecture of future wireless communication systems. However, its performance is constrained by the capability of fr...Cloud computing.based heterogeneous networks(C.Het Nets) have been considered as promising network architecture of future wireless communication systems. However, its performance is constrained by the capability of fronthaul. To study the performance limit of C.Het Nets, the coverage performance of the open access strategy in C.Het Nets is analyzed in this paper. In particular, the non.ideal condition of fronthaul in C.Het Nets is characterized by establishing a stochastic geometry.based model, and a tight lower bound on coverage probability is derived for downlink transmissions. Based on the derived results, the constraint of the fronthaul is given to ensure that open access strategy can achieve the best coverage performance. Finally, the simulation results are provided to verify the theoretical results and show the impact of fronthaul constrains.展开更多
We put forward an n-ZnO/p-Si heterojunction solar cell model based on AFORS-HET simulations and provide experimental support in this article.ZnO:B(B-doped ZnO) thin films deposited by metal-organic chemical vapor d...We put forward an n-ZnO/p-Si heterojunction solar cell model based on AFORS-HET simulations and provide experimental support in this article.ZnO:B(B-doped ZnO) thin films deposited by metal-organic chemical vapor deposition(MOCVD) are planned to act as electrical emitter layer on p-type c-Si substrate for photovoltaic applications.We investigate the effects of thickness,buffer layer,ZnO:B affinity and work function of electrodes on performances of solar cells through computer simulations using AFORS-HET software package.The energy conversion efficiency of the ZnO:B(n)/ZnO/c-Si(p) solar cell can achieve 17.16%(V(oc):675.8 mV,J(sc):30.24 mA/cm^2,FF:83.96%) via simulation.On a basis of optimized conditions in simulation,we carry out some experiments,which testify that the ZnO buffer layer of 20 nm contributes to improving performances of solar cells.The influences of growth temperature,thickness and diborane(B2H6) flow rates are also discussed.We achieve an appropriate condition for the fabrication of the solar cells using the MOCVD technique.The obtained conversion efficiency reaches2.82%(V(oc):294.4 mV,J(sc):26.108 mA/cm^2,FF:36.66%).展开更多
基金supported in part by the National Natural Science Foundation of China (Grant 61501045)in part by State Major Science and Technology Special Projects (Grant 2016ZX03001017-004)
文摘Cloud computing.based heterogeneous networks(C.Het Nets) have been considered as promising network architecture of future wireless communication systems. However, its performance is constrained by the capability of fronthaul. To study the performance limit of C.Het Nets, the coverage performance of the open access strategy in C.Het Nets is analyzed in this paper. In particular, the non.ideal condition of fronthaul in C.Het Nets is characterized by establishing a stochastic geometry.based model, and a tight lower bound on coverage probability is derived for downlink transmissions. Based on the derived results, the constraint of the fronthaul is given to ensure that open access strategy can achieve the best coverage performance. Finally, the simulation results are provided to verify the theoretical results and show the impact of fronthaul constrains.
基金Project supported by the State Key Development Program for Basic Research of China(Nos.2011CBA00706,2011CBA00707)the Tianjin Applied Basic Research Project and Cutting-Edge Technology Research Plan(No.13JCZDJC26900)+2 种基金the Tianjin Major Science and Technology Support Project(No.11TXSYGX22100)the National High Technology Research and Development Program of China(No.2013AA050302)the Fundamental Research Funds for the Central Universities(No.65010341)
文摘We put forward an n-ZnO/p-Si heterojunction solar cell model based on AFORS-HET simulations and provide experimental support in this article.ZnO:B(B-doped ZnO) thin films deposited by metal-organic chemical vapor deposition(MOCVD) are planned to act as electrical emitter layer on p-type c-Si substrate for photovoltaic applications.We investigate the effects of thickness,buffer layer,ZnO:B affinity and work function of electrodes on performances of solar cells through computer simulations using AFORS-HET software package.The energy conversion efficiency of the ZnO:B(n)/ZnO/c-Si(p) solar cell can achieve 17.16%(V(oc):675.8 mV,J(sc):30.24 mA/cm^2,FF:83.96%) via simulation.On a basis of optimized conditions in simulation,we carry out some experiments,which testify that the ZnO buffer layer of 20 nm contributes to improving performances of solar cells.The influences of growth temperature,thickness and diborane(B2H6) flow rates are also discussed.We achieve an appropriate condition for the fabrication of the solar cells using the MOCVD technique.The obtained conversion efficiency reaches2.82%(V(oc):294.4 mV,J(sc):26.108 mA/cm^2,FF:36.66%).