We demonstrate that an asynchronous CSMA/CD protocol with an optical loop-back star coupler can achieve high upstream channel utilizatbn in an Ethernet PON, readily supporting a large installed base of Ethernet 10Base...We demonstrate that an asynchronous CSMA/CD protocol with an optical loop-back star coupler can achieve high upstream channel utilizatbn in an Ethernet PON, readily supporting a large installed base of Ethernet 10BaseT and 100BaseT interfaces.展开更多
Hybrid Power-line/Visible-light Communication(HPVC)network has been one of the most promising Cooperative Communication(CC)technologies for constructing Smart Home due to its superior communication reliability and har...Hybrid Power-line/Visible-light Communication(HPVC)network has been one of the most promising Cooperative Communication(CC)technologies for constructing Smart Home due to its superior communication reliability and hardware efficiency.Current research on HPVC networks focuses on the performance analysis and optimization of the Physical(PHY)layer,where the Power Line Communication(PLC)component only serves as the backbone to provide power to light Emitting Diode(LED)devices.So designing a Media Access Control(MAC)protocol remains a great challenge because it allows both PLC and Visible Light Communication(VLC)components to operate data transmission,i.e.,to achieve a true HPVC network CC.To solve this problem,we propose a new HPC network MAC protocol(HPVC MAC)based on Carrier Sense Multiple Access/Collision Avoidance(CSMA/CA)by combining IEEE 802.15.7 and IEEE 1901 standards.Firstly,we add an Additional Assistance(AA)layer to provide the channel selection strategies for sensor stations,so that they can complete data transmission on the selected channel via the specified CSMA/CA mechanism,respectively.Based on this,we give a detailed working principle of the HPVC MAC,followed by the construction of a joint analytical model for mathematicalmathematical validation of the HPVC MAC.In the modeling process,the impacts of PHY layer settings(including channel fading types and additive noise feature),CSMA/CA mechanisms of 802.15.7 and 1901,and practical configurations(such as traffic rate,transit buffer size)are comprehensively taken into consideration.Moreover,we prove the proposed analytical model has the solvability.Finally,through extensive simulations,we characterize the HPVC MAC performance under different system parameters and verify the correctness of the corresponding analytical model with an average error rate of 4.62%between the simulation and analytical results.展开更多
A three-dimensional(3 D) Cd-based metal-organic framework(MOF), [Cd(H2 O)(PAA)]·(H2 O)2(complex 1) has been rationally designed and synthesized by using 4-(pyrimidin-5-yl)isophthalic acid(H2 PAA) and Cd(NO3)2...A three-dimensional(3 D) Cd-based metal-organic framework(MOF), [Cd(H2 O)(PAA)]·(H2 O)2(complex 1) has been rationally designed and synthesized by using 4-(pyrimidin-5-yl)isophthalic acid(H2 PAA) and Cd(NO3)2·4 H2 O under solvothermal conditions. The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction(PXRD) and thermogravimetric analyses(TGA). Single-crystal X-ray diffraction analyses reveal that complex 1 consists of a 3 D network with one-dimensional(1 D) channels. Moreover, 1 exhibits strong luminescent emission in solid state at room temperature. Fluorescence quenching was observed when treating complex 1 with picric acid(PA), 2,4-dinitrophenylhydrazine(2,4-DNPH) and p-nitroaniline(p-NA), revealing that the as-synthesized complex could be used as a luminescence sensor for the detection of PA, 2,4-DNPH and p-NA.展开更多
文摘We demonstrate that an asynchronous CSMA/CD protocol with an optical loop-back star coupler can achieve high upstream channel utilizatbn in an Ethernet PON, readily supporting a large installed base of Ethernet 10BaseT and 100BaseT interfaces.
基金supported by the National Natural Science Foundation of China(No.61772386)National Key Research and Development Project(No.2018YFB1305001)Fundamental Research Funds for the Central Universities(No.KJ02072021-0119).
文摘Hybrid Power-line/Visible-light Communication(HPVC)network has been one of the most promising Cooperative Communication(CC)technologies for constructing Smart Home due to its superior communication reliability and hardware efficiency.Current research on HPVC networks focuses on the performance analysis and optimization of the Physical(PHY)layer,where the Power Line Communication(PLC)component only serves as the backbone to provide power to light Emitting Diode(LED)devices.So designing a Media Access Control(MAC)protocol remains a great challenge because it allows both PLC and Visible Light Communication(VLC)components to operate data transmission,i.e.,to achieve a true HPVC network CC.To solve this problem,we propose a new HPC network MAC protocol(HPVC MAC)based on Carrier Sense Multiple Access/Collision Avoidance(CSMA/CA)by combining IEEE 802.15.7 and IEEE 1901 standards.Firstly,we add an Additional Assistance(AA)layer to provide the channel selection strategies for sensor stations,so that they can complete data transmission on the selected channel via the specified CSMA/CA mechanism,respectively.Based on this,we give a detailed working principle of the HPVC MAC,followed by the construction of a joint analytical model for mathematicalmathematical validation of the HPVC MAC.In the modeling process,the impacts of PHY layer settings(including channel fading types and additive noise feature),CSMA/CA mechanisms of 802.15.7 and 1901,and practical configurations(such as traffic rate,transit buffer size)are comprehensively taken into consideration.Moreover,we prove the proposed analytical model has the solvability.Finally,through extensive simulations,we characterize the HPVC MAC performance under different system parameters and verify the correctness of the corresponding analytical model with an average error rate of 4.62%between the simulation and analytical results.
基金supported by the Natural Science Foundation of Shaanxi Province(2018JQ2079,2018JQ2040,2018JM2055)
文摘A three-dimensional(3 D) Cd-based metal-organic framework(MOF), [Cd(H2 O)(PAA)]·(H2 O)2(complex 1) has been rationally designed and synthesized by using 4-(pyrimidin-5-yl)isophthalic acid(H2 PAA) and Cd(NO3)2·4 H2 O under solvothermal conditions. The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction(PXRD) and thermogravimetric analyses(TGA). Single-crystal X-ray diffraction analyses reveal that complex 1 consists of a 3 D network with one-dimensional(1 D) channels. Moreover, 1 exhibits strong luminescent emission in solid state at room temperature. Fluorescence quenching was observed when treating complex 1 with picric acid(PA), 2,4-dinitrophenylhydrazine(2,4-DNPH) and p-nitroaniline(p-NA), revealing that the as-synthesized complex could be used as a luminescence sensor for the detection of PA, 2,4-DNPH and p-NA.
