Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO sy...Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and uplink.To solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul capacity.Three sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm criteria.Convergence and complexity analysis are presented for the algorithms.The provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.展开更多
Sensitive and fast detection of ibuprofen( Ibu) in an aquatic environment often requires costly, time-consuming and sophisticated techniques. To tackle those limitations,a novel android smartphone application was deve...Sensitive and fast detection of ibuprofen( Ibu) in an aquatic environment often requires costly, time-consuming and sophisticated techniques. To tackle those limitations,a novel android smartphone application was developed based on a colorimetric analysis method using unmodified gold nanoparticles( AuNPs)aptamer probes to quantitatively detect Ibu. Under optimal conditions,it could detect Ibu as low as 0. 25 ng/mL with high selectivity. The determination of Ibu in real water samples was also carried out to confirm the practicability of the application.展开更多
基金supported in part by National Natural Science Foundation of China No.61171080
文摘Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and uplink.To solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul capacity.Three sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm criteria.Convergence and complexity analysis are presented for the algorithms.The provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.
基金National Natural Science Foundation of China(No.21377023)
文摘Sensitive and fast detection of ibuprofen( Ibu) in an aquatic environment often requires costly, time-consuming and sophisticated techniques. To tackle those limitations,a novel android smartphone application was developed based on a colorimetric analysis method using unmodified gold nanoparticles( AuNPs)aptamer probes to quantitatively detect Ibu. Under optimal conditions,it could detect Ibu as low as 0. 25 ng/mL with high selectivity. The determination of Ibu in real water samples was also carried out to confirm the practicability of the application.
