In order to realize the reduction of equipment cost and the demand of higher capacity, wireless mesh network （WMN） router devices usually have several interfaces and work on multi-channels. Jointing channel allocati...In order to realize the reduction of equipment cost and the demand of higher capacity, wireless mesh network （WMN） router devices usually have several interfaces and work on multi-channels. Jointing channel allocation, interface assignment and routing can efficiently improve the network capacity. This paper presents an efficient channel assignment scheme combined with the multi-radio link quality source routing （MR-LQSR） protocol, which is called channel assignment with MR-LQSR （CA-LQSR）. In this scheme, a physical interference model is established： calculated transmission time （CTT） is proposed as the metric of channel assignment, which can reflect the real network environment and channel interference best, and enhanced weighted cumulative expected transmission time （EWCETT） is proposed as the routing metric, which preserves load balancing and bandwidth of links. Meantime, the expression of EWCETT contains the value of CTT, thus the total cost time of channel assignment and routing can be reduced. Simulation results show that our method has advantage of higher throughput, lower end-to-end time delay, and less network cost over some other existing methods.展开更多
A new crystal,Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7),was obtained by substituting Ga^(3+)ions for some Al^(3+)ions in Ca_(2)Al_(2)SiO_(7)crystal.The growth,structure and optical spectroscopic properties of Cr^(4+)-doped Ca_(...A new crystal,Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7),was obtained by substituting Ga^(3+)ions for some Al^(3+)ions in Ca_(2)Al_(2)SiO_(7)crystal.The growth,structure and optical spectroscopic properties of Cr^(4+)-doped Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)were studied.It shows strong absorption at 693 and 762 nm and a broad emission band with peak wavelength at 1223 nm.Both the absorption and emission peaks of Cr^(4+)-doped Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)crystal are red-shifted in comparison with that of Cr^(4+)-doped Ca_(2)Al_(2)SiO_(7)crystal due to its weaker lattice field.The investigation results show that there is only one kind of tetrahedral site for Cr^(4+)occupation in the lattice of Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)crystal.展开更多
基金supported by the Fundamental Research Funds for the Central Universities (2009RC0308)
文摘In order to realize the reduction of equipment cost and the demand of higher capacity, wireless mesh network （WMN） router devices usually have several interfaces and work on multi-channels. Jointing channel allocation, interface assignment and routing can efficiently improve the network capacity. This paper presents an efficient channel assignment scheme combined with the multi-radio link quality source routing （MR-LQSR） protocol, which is called channel assignment with MR-LQSR （CA-LQSR）. In this scheme, a physical interference model is established： calculated transmission time （CTT） is proposed as the metric of channel assignment, which can reflect the real network environment and channel interference best, and enhanced weighted cumulative expected transmission time （EWCETT） is proposed as the routing metric, which preserves load balancing and bandwidth of links. Meantime, the expression of EWCETT contains the value of CTT, thus the total cost time of channel assignment and routing can be reduced. Simulation results show that our method has advantage of higher throughput, lower end-to-end time delay, and less network cost over some other existing methods.
基金the National Natural Science Foundation of China(No.61775217)。
文摘A new crystal,Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7),was obtained by substituting Ga^(3+)ions for some Al^(3+)ions in Ca_(2)Al_(2)SiO_(7)crystal.The growth,structure and optical spectroscopic properties of Cr^(4+)-doped Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)were studied.It shows strong absorption at 693 and 762 nm and a broad emission band with peak wavelength at 1223 nm.Both the absorption and emission peaks of Cr^(4+)-doped Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)crystal are red-shifted in comparison with that of Cr^(4+)-doped Ca_(2)Al_(2)SiO_(7)crystal due to its weaker lattice field.The investigation results show that there is only one kind of tetrahedral site for Cr^(4+)occupation in the lattice of Ca_(2)(Al_(1.8)Ga_(0.2))SiO_(7)crystal.
