With the deployment and commercial application of 5G, researchers start to think of 6G, which could meet more diversified and deeper intelligent communication requirements. In this paper, a four physical elements, i.e., man, machine, object, and genie, featured 6G concept is introduced. Genie is explained as a new element toward 6G. This paper focuses on the genie realization as an intelligent wireless transmission toward 6G, including sematic information theory, end-to-end artificial intelligence (AI) joint transceiver design, intelligent wireless transmission block design, and user-centric intelligent access. A comprehensive state-of-the-art of each key technology is presented and main questions as well as some novel suggestions are given. Genie will work comprehensively in 6G wireless communication and other major industrial vertical, while its realization is concrete and step by step. It is realized that genie-based wireless communication link works with high intelligence and performs better than that controlled manually.
25 April 2021 in Journal of Geophysical Research: Space Physics
The great solar eclipse traveled eastward through the American Continent from coast to coast on August 21, 2017 and provided a rare opportunity to investigate the ionospheric responses to the rapid solar radiation variations. We have analyzed the peak electron density and density gradient variations in Sporadic E (Es) and applied the data of four Digisondes close to the eclipse path. All the four Digisondes have recorded the same interesting phenomena. One is the depletion on the fbEs (blanketing frequency of Es layer) curve during the solar eclipse and the other is the enhancements on the semi‐transparency parameter of Es layer Δf after the solar eclipse, where Δf = ftEs−fbEs, and ftEs is the top frequency of Es layer. The wind disturbances on the tidal wind and the photoionization decrease during the eclipse are put forward as a possible reason for the peak plasma density reduce. The periodic gravity waves have been observed in both ionospheric E and F region. However, the Δf enhancements occurred after the gravity waves had passed through the Es layer. Thus, we suggest that the solar induced waves did not raise the plasma density gradient directly. Gravity waves breaking may occur in the Mesosphere/Lower Thermosphere region to deposit momentum and produce turbulence, and so the accompanying instabilities may be generated to enhance the electron density gradient in E‐region.
Based on two meteor radars in mid‐latitudes of China, the mid‐latitude lower thermospheric neutral wind responses to the 2015 St. Patrick's Day great storm are investigated. The AE and PCN indices presented the similar quasi‐5‐hour oscillations during the storm. Interestingly, the analogous and close‐correlated storm‐time quasi‐5‐hour oscillations were also observed in both the meridional wind differences at 90–102 km derived from meteor radars. The meridional wind disturbances in the lower thermosphere also showed the extension toward the lower latitudes. It has been found that the enhanced equatorward wind disturbances at 250 km estimated by the Horizontal Wind Model‐14 and Fabry‐Perot Interferometer (FPI) emerged accordingly with the increases of AE and PCN with a time delay. And the enhancements of equatorward (poleward) wind disturbances at 250 km were accompanied by the increments of equatorward (poleward) wind disturbances at 94 km with a time lag of a few hours. It is thus suggested that the multiple intensified Joule heating events with quasi‐5‐hour time intervals were triggered by the successive substorm expansions during the storm. Then the Joule heating events led to the vertical wind and temperature disturbances in the mid‐latitude lower thermosphere via disturbing the thermospheric meridional circulation, which consequently induced the quasi‐5‐hour meridional wind disturbances therein.
8 June 2022 in Journal of Geophysical Research: Space Physics
Statistical characteristics of the E‐region irregularities observed by the HCOPAR in the low‐latitudes of China are presented and analyzed. The data come from the observations between September 2015 and August 2016. Benefit from the high data acquisition rate and the relatively high time and height resolutions, we have found many interesting and unreported details in the statistical characteristics of the E‐region irregularities. The lowest occurrence rate of the E‐region irregularities appears at around sunrise and another low rate appears at around noon. The daytime irregularities are generated in the region where the zonal winds turn around at the E‐region altitudes. There is clear boundary between the irregularities occurring in the morning and afternoon. The nighttime irregularities appear at higher altitudes with steeper background plasma density gradient. The higher tidal amplitude is suggested to increase the irregularity occurrence rate and the greater solar radiation is suggested to decrease it. The steep plasma density gradient in the night may be the main reason for the nighttime irregularities through gradient drift instability. The turning around of the zonal wind field is considered to generate the irregularities in the day through Kelvin‐Helmholtz instability.