Increasing the spectral efficiency and per channel data rate have historically been shown to be the most cost-effective method to meet the need of ever growing capacity demand in the core network. In this paper we rev...Increasing the spectral efficiency and per channel data rate have historically been shown to be the most cost-effective method to meet the need of ever growing capacity demand in the core network. In this paper we review recent progress in high-speed and high-spectral-efficient optical transmission technology. We discuss spectrally efficient modulation and detection technologies that have been experimentally explored for future 100-Gb/s and above optical transmission system. Emerging methods aiming at extending system reach for noise and nonlinearity-stressed high spectral efficiency optical transmission systems have also been reviewed. We show that spectrallyefficient multilevel coding coupled with polarization multiplexing and digital coherent detection has the potential to enable 400Gb/s per channel WDM system operating with existing 50GHzspaced WDM infrastructure at a spectral efficiency of 8b/s/Hz.展开更多
In this paper, a novel unmanned aerial vehicle(UAV)-enabled full duplex decode-and-forward(DF) technique is used in mobile relaying system. Compared with conventional static relaying, mobile relaying provides more deg...In this paper, a novel unmanned aerial vehicle(UAV)-enabled full duplex decode-and-forward(DF) technique is used in mobile relaying system. Compared with conventional static relaying, mobile relaying provides more degree of freedom for experiencing better channel conditions and further improving the system reliable performance. The source and relay transmit power as well as relay trajectory are jointly optimized for sum outage probability minimization in mobile relaying system. Due to the non-convex nature of the original problem, block coordinate decent optimization techniques are employed to decompose it into two sub-problems, which leads to an efficient iterative algorithm. Specifically, for the pre-determined relay trajectory, the optimal transmit power of source and relay are obtained by solving Karush-Kuhn-Tucker(KKT) conditions. For the given source/relay power allocation, the optimal UAV trajectory is obtained by solving dual problem. Based on the two steps, an iterative algorithm is proposed to jointly optimize source/relay power allocation and UAV trajectory alternately. Numerical results show the performance gain of our proposed scheme.展开更多
Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric cu...Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric current is required to impose the magnetic field on the ship hull, which in turn means that the deperming coil needs to be wound on ship hull when the coil is composed of conventional conductive materials, such as copper. We considered a few HTS （high temperature superconducting） coil systems to deperm naval ships because we expect the shorter deperming time and lower manual workload for ship deperming operation, compared conventional conductor coil systems. We have in the past presented a solution using a fiat two-coil system arranged on seabed with tightly bound HTS conductor by analytical calculation of magnetic field on the conductor. By considering present and already developed technologies, a conductor with cylindrically wound on the core arranged as fiat multi-turn coils on seabed was designed using analytical methods.展开更多
文摘Increasing the spectral efficiency and per channel data rate have historically been shown to be the most cost-effective method to meet the need of ever growing capacity demand in the core network. In this paper we review recent progress in high-speed and high-spectral-efficient optical transmission technology. We discuss spectrally efficient modulation and detection technologies that have been experimentally explored for future 100-Gb/s and above optical transmission system. Emerging methods aiming at extending system reach for noise and nonlinearity-stressed high spectral efficiency optical transmission systems have also been reviewed. We show that spectrallyefficient multilevel coding coupled with polarization multiplexing and digital coherent detection has the potential to enable 400Gb/s per channel WDM system operating with existing 50GHzspaced WDM infrastructure at a spectral efficiency of 8b/s/Hz.
基金supported by National High Technology Project of China 2015AA01A703Scientific and Technological Key Project of Henan Province under Grant 182102210449the National Natural Science Foundation of China under Grants 61372101 and 61671144
文摘In this paper, a novel unmanned aerial vehicle(UAV)-enabled full duplex decode-and-forward(DF) technique is used in mobile relaying system. Compared with conventional static relaying, mobile relaying provides more degree of freedom for experiencing better channel conditions and further improving the system reliable performance. The source and relay transmit power as well as relay trajectory are jointly optimized for sum outage probability minimization in mobile relaying system. Due to the non-convex nature of the original problem, block coordinate decent optimization techniques are employed to decompose it into two sub-problems, which leads to an efficient iterative algorithm. Specifically, for the pre-determined relay trajectory, the optimal transmit power of source and relay are obtained by solving Karush-Kuhn-Tucker(KKT) conditions. For the given source/relay power allocation, the optimal UAV trajectory is obtained by solving dual problem. Based on the two steps, an iterative algorithm is proposed to jointly optimize source/relay power allocation and UAV trajectory alternately. Numerical results show the performance gain of our proposed scheme.
文摘Naval ship deperming is effective to reduce the potential damage from sea mines some of which sense magnetic field of the ship, and thus, is an important treatment of naval ships in the recent world. Large electric current is required to impose the magnetic field on the ship hull, which in turn means that the deperming coil needs to be wound on ship hull when the coil is composed of conventional conductive materials, such as copper. We considered a few HTS （high temperature superconducting） coil systems to deperm naval ships because we expect the shorter deperming time and lower manual workload for ship deperming operation, compared conventional conductor coil systems. We have in the past presented a solution using a fiat two-coil system arranged on seabed with tightly bound HTS conductor by analytical calculation of magnetic field on the conductor. By considering present and already developed technologies, a conductor with cylindrically wound on the core arranged as fiat multi-turn coils on seabed was designed using analytical methods.
