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The recently promulgated US military standard MIL-STD-188-110C contains an appendix (Appendix D) defining a new family of wideband HF data waveforms supporting bandwidths from 3 kHz to 24 kHz in increments of 3 kHz. This family of waveforms extends the high performance serial tone modem technology of the MIL-STD-188-110B standard to wider bandwidths and much higher data rates, allowing users the option...
The ionosphere is an important source of positioning error for Global Navigation Satellite Systems GNSS. The factors affecting the GNSS signals are introduced and the implications for modern GNSS applications are discussed. The paper also describes the current use of Global Navigation Satellite Systems for ionospheric corrections and shows specific examples of the use of GNSS for ionospheric measurement.
Procedures for the long-term prediction of performance of terrestrial HF systems have been based on the prediction of monthly median conditions, with the subsequent application of statistical distributions, or geophysical or solar parameters, for other time percentages. However, there may be little correlation with time or location of ionospheric variability for various ionospheric parameters. The...
Harris Corporation and the State University of New York at Buffalo are conducting a collaborative project to develop an HF network simulation framework based on the ns-2 open-source network simulator. The framework will contain models of HF channel characteristics, waveforms, protocols, and typical traffic loads, so as to be useful for analyzing HF radio networks under real-world conditions. This...
HF radio propagation via the ionosphere in the polar cap is strongly affected by the features such as patches and arcs that are present there. These effects include significant, and at times total, attenuation in the D-region and off-great circle propagation leading to delay spread, Doppler, and directional characteristics not predicted or considered by empirical prediction tools such as VOACAP. In...
It is clear that in the near future much broader transmissions in the HF band will replace part of the current narrow band links. Our personal view is that a real wide band signal is infeasible in this environment because the usage is typically very intensive and may suffer interferences from all over the world. Therefore, we envision that dynamic multiband transmissions may provide better satisfactory...
This paper proposes a MIMO 2×2 solution to increase the capacity of HF radio links through the ionospheric channel. A diversity in the transmitted polarizations replaces the classical space diversity and authorizes a compact set up in a context of decametric wavelengths. After a theoretical step of capacity estimation, an HF 2×2 MIMO system has been designed and tested on a 280 km long radio link...
In this paper, a Monte Carlo method has been applied to calculating the multipath spread of HF signals from VOACAP predictions. This method uses the predicted SNR probability distribution functions rather than just taking the median SNR to provide a probability distribution of multipath spread values. Predictions are compared with measurements over two paths, one at mid-latitudes and the second at...
We describe the experiments carried out in 2009–2011 on the modification of the midlatitude ionosphere by powerful HF-heating from the Sura facility near N. Novgorod (Russia). We analyze the responses of the GPS/GLONASS and Parus/Tsikada satellite radio signals to the heating-induced disturbances in electron density. We study the variations in the total electron content (TEC), which are proportional...
This article presents the derivation of governing equations for the propagating wave under the influence of magneto-ionic plasma (i.e. Earth's Ionosphere), ready to be used in Finite Difference Time Domain algorithm. The governing equations and constituent relations are derived from the magnetoionic theory given by Appleton-Hartree, discussed by Ratcliffe and Budden. The frequency domain relations,...
The recently completed US MIL-STD-188-110C Appendix D specifies a new family of Wideband HF Waveforms. These new waveforms occupy bandwidths from 3 kHz to 24 kHz in increments of 3 KHz and provide user data rates between 75 bps and 120,000 bps. This enhancement to the standard addresses the need for higher capacity and throughput in today's HF communication systems needed to support IP based data...
The analytical solution to the spaced position and frequency coherence functions of the GNSS type fields propagating through the ionosphere is given. The explicitly constructed coherence functions are obtained for the quadratic structure function of the electron density fluctuations of the ionosphere and the inhomogeneous background ionosphere, where the dependence of the plasma frequency along the...
We envision that dynamic multiband transmissions taking advantage of the receiver diversity (even for collocated antennas with different polarization or radiation pattern) will create a new paradigm for these links guaranteeing high quality and reliability. However, there are many challenges to face regarding the use of broadband reception where several out of band (with respect to multiband transmission)...
Differences in behaviour between 2G and 3G (Fast Link Setup or FLSU) ALE linking protocols are analysed using a common Discrete Event Simulation (DES) architecture designed to focus on the impact on overall HF network performance due to differences in the ALE linking protocols rather than differences due to their waveforms. This was achieved by setting the statistical likelihood of linking to be the...
In this paper Cognitive Radio (CR) concepts being investigated by European researchers for V/UHF radio systems are highlighted. A CR policy box, previously developed by QinetiQ, is then described. The IEEE 802.22 application scenario which aims to exploit TV “white spaces” is then outlined and how this scenario may be translated to the HF domain is described. The paper then considers enhancement to...
The Swedish Armed Forces use HF manpack radios to communicate between vehicles and base stations in international missions, such as ISAF in Afghanistan and the EU Nordic Battle Group 2011. During 2011 a major upgrade of the whole information system was planned including replacing the old 2G-ALE radios with the 3G-ALE based Harris RF-5800H manpack radio system. A number of enhancements to the 3G-ALE...
The reliability of bidirectional communication link can be guaranteed with Automatic Repeat Request Procedures (ARQ). The standard STANAG 5066 describes the ARQ procedure for HF communications that can either be applied to existing HF physical layers modems or adapted to future physical layer designs. In this contribution the physical layer parameters of an HF modem (HFDVL), developed by the authors...
Achieving reliable communication over HF channels is known to be challenging due to the particularly hostile propagation medium. To address this problem, diversity techniques were shown to be promising. In this paper, we demonstrate through experimental results the benefits of different diversity strategies when applied to multi-input-multi-output (MIMO) multicarrier systems. The performance gains...
Previously, the majority of developments in the area of multiple input multiple output (MIMO) technology have been confined to short-range wireless applications operating in the VHF, UHF and SHF bands, with very little research conducted in the lower frequency bands. Recently, several experimental campaigns have been performed over a 255 km radio link between Durham and Leicester in the UK in order...
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