Midlatitude ionospheric HF channel reciprocity: Evidence from the ionospheric oblique incidence sounding experiments

Abstract

[1] Ionospheric HF channel reciprocity is investigated at middle latitudes on the basis of ionospheric oblique incidence sounding experiments. Two identical Wuhan Ionospheric Oblique Incidence Sounding Systems (WIOISS), located at Wuhan (30°32′N, 114°21′E) and Wanning (18°58′N, 110°31′E), are used to carry out the campaign. Comparisons of group distance and Doppler shift between Wuhan-Wanning and Wanning-Wuhan HF ionospheric propagation paths indicate that the reciprocity of the ionospheric HF channel is satisfied at midlatitude region. A 3-D ray tracing simulation is also implemented to evaluate the group distances of the two paths. Midlatitude ionospheric HF channel reciprocity, as verified both experimentally and theoretically in the present study, can be useful for HF communication systems and sky wave over-the-horizon radars.

Wuhan Ionospheric Oblique Backscattering Sounding System and Its Applications—A Review

“…With the oblique-incidence ionograms provided by WIOBSS, several parameters of the HF channel can be obtained in real-time, including the lowest usable frequency, the maximum usable frequency, the Doppler spread, the multipath spread, the attenuation, and the signal-to-noise ratio. Furthermore, Zhou et al established a real-time mapping model of the critical frequency of the F 2 layer in Northern China by using neural networks [ 149 ], and investigated the ionospheric HF channel reciprocity at middle latitudes [ 150 ].…”

Automatic scaling of HF swept‐frequency backscatter ionograms

“…Spherical focusing and time focusing of ionosphere make the echoes have steep leading edge [ Xiong et al ., ]. At present, oblique backscatter sounding has been successfully used in the following four aspects: (1) providing available spectrum for frequency management system of sky wave over‐the‐horizon radar and for real‐time frequency selective system of short‐wave communication [ Earl and Ward , ; Bazin et al ., ; Saverino et al ., ]; (2) monitoring and forecasting working conditions over HF links, such as the coverage area of radio waves and maximum available frequency [ Zhao , ]; (3) deciding the ground distance by using the leading edges in backscatter ionograms [ Jiao and Zhu , ; Huang and Li , ; Li and Jiao , ; Li , ]; and (4) acquiring structure and state information of ionosphere by using the leading edges in backscatter ionograms [ Norman , ; Norman and Dyson , ; Fridman et al ., ; Benito et al ., ; Li et al ., ; Song et al ., ; Zhou et al ., , ]. These applications all rely on accurate extraction and analysis of real‐time backscatter ionograms.…”

Cross-layer design to maintain earthquake sensor network connectivity after loss of infrastructure

“…When a sensor wishes to communicate to the server at a specific time, it can compensate for the delay such that the signal arrives at the server at the correct time according to the server's clock. Assuming channel reciprocity (demonstrated for this physical layer in [4]), this information can also be calibrated to regular server transmissions.…”