Measurement of the Ionospheric Reflection Height of an HF Wave in Vertical Incidence With a Resolution of Minutes

Guzmán, L A Agüero; Ovalle, E.; Reeves, R.

doi:10.1109/lgrs.2018.2856110

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…The transmission of traditional radio frequencies (wavelengths of 1 m or more) between ground stations and satellites can be disrupted for several hours following a high-altitude nuclear detonation [14]. The change in the electron density of the ionosphere (D, E, and F regions [15]) following a high-altitude nuclear detonation leads to the degradation of the propagation of radio frequency waves by altering the refractive index of the plasma in the upper atmosphere and through increased absorption [14]. The disruption of radio communications frequencies is commonly referred to as radio blackout.…”

Section: Nuclear Disturbed Environmentmentioning

confidence: 99%

Optical noise in a free-space quantum communications link from natural and nuclear disturbed environments*

et al. 2022

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Satellite communications at radio frequencies can experience a "blackout" period following the atmospheric detonation of a nuclear weapon. The wavelengths used for free-space quantum communications will not incur the same "blackout" effects from a nuclear detonation, but the optical systems will suffer from a phenomenon called redout. Redout occurs in an optical detector when ambient light scatters into the optical receiver, causing elevated background photon counts in the detector such that background noise overwhelms the signal. In this work, the duration of the redout effect is quantified from a nuclear disturbed environment on a ground-to-space quantum optical link. In addition, we comment on various techniques for reducing ambient and nuclear disturbed background counts in a quantum free-space optical link. For low altitude nuclear detonations (i.e., under 50 km), the maximum interference time will be less than 1 min. Implementing a telescope, timing gate, and wavelength filter to the detector can reduce the background counts in the detector significantly. Aerosol levels and ground albedo are major contributors to background noise in a ground-to-satellite quantum channel, and ground station location should factor in both variables.

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Section: Nuclear Disturbed Environmentmentioning

confidence: 99%

Optical noise in a free-space quantum communications link from natural and nuclear disturbed environments*

et al. 2022

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“…This offers several projects to make a flexible software radio system utilizing various software libraries. In [16], The researcher received a 3-30MHz frequency band experimental SDR receiver with the aid of GRC / FPGA programmable hardware. In [17], Writer suggested a wide-band frame-level adaptation that can be simply implemented in various protocols.…”

Section: Softwarementioning

confidence: 99%

Testing different Channel Estimation Techniques in Real-Time Software Defined Radio Environment

Ponnaluru¹,

Satyanarayana²

2020

IJACSA

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In modern wireless communication to maximize spectral efficiency and to minimize the bit error rate OFDM (Orthogonal frequency-domain multiplexing) is used. OFDM is used broadly in networks using various protocols, including wireless vehicular environment IEEE 802.11p, IEEE 802.16d/e Wireless Metropolitan Area Networks, Long-Term Evolution 3GPP networks and IEEE 802.11a/g/n Wireless Local Area Networks. The main challenges involved when using OFDM for wireless communications are short channel-coherence bandwidth and the narrow coherence time, and both have a major effect on the reliability and latency of data packet communication. These properties increase the difficulty of channel equalization because the channel may change drastically over the period of a single packet. Spectral Temporal Averaging is an enhanced decisiondirected channel equalization technique that improves communication performance (as far as the frame delivery ratio (FDR) and throughput) in typical channel conditions. This paper reports tests of Spectral Temporal Averaging channel equalization in an IEEE 802.11a network, compared with other channel equalization techniques in terms of the FDR in a realtime environment. Herein, a software defined Radio (SDR) platform was used for estimating the channel. This proves that the system can provide over 90% of delivery ratio at 25 db of Signal to Noise Ratio (SNR) for various digital modulation techniques. For this purpose, an experimental setup consisting of software-defined radio, Universal Software Radio Peripheral (USRP) N210 along with wide bandwidth daughter board as hardware and GNU radio is used.

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“…It covers a wide range of projects to build a variable software radio system using many libraries presented in it. In [6] using GNURadio/FPGA reconfigurable hardware, author presented a prototype in 3-30MHz frequency band of an RF signal receiver in SDR platform. In [7] author proposed a wide-band spectrum adaption at frame-level which can be easily implemented into devices in different protocols.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Data Transfer Based on Software Defined Radio Technique using Gnu radio/USRP

Sowjanya,

Satyanarayana

2019

IJEAT

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Software Defined Radio (SDR) offers a extensive radio communication platform that uses software updates to make use of fresh technology. From SDR, the idea of an Orthogonal frequency division multiplexing (OFDM) has evolved to personalize SDRs. The channel dispersiveness causes Inter Symbol Interference (ISI) but OFDM is more resistant at these condition because of this reason it is widely used in wireless communication systems. OFDM is having a good performance in terms of Bit Error Rate (BER) and high spectrum efficiency, so it is considered as a key role for next generation wireless communication system. In this paper, three different types of data are transferred in a real time SDR of OFDM transceiver using GNURadio/Universal Software Radio Peripheral (USRP). OFDM is extremely sensitive for synchronization errors such as time and frequency offsets and to estimate channel condition. Therefore, a standard algorithm is applied to solve synchronization and channel estimation problems in SDR based OFDM system. This testbed is implemented using two USRPs of model N210 as transmitter and receiver with an open source of GNURadio as a software. The implementation of OFDM is evaluated for different types of information like text, audio and Image. This evaluates the BER v/s SNR for real time data transmission in SDR Environment

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Measurement of the Ionospheric Reflection Height of an HF Wave in Vertical Incidence With a Resolution of Minutes

Cited by 3 publications

References 10 publications

Optical noise in a free-space quantum communications link from natural and nuclear disturbed environments*

Optical noise in a free-space quantum communications link from natural and nuclear disturbed environments*

Testing different Channel Estimation Techniques in Real-Time Software Defined Radio Environment

Real-Time Data Transfer Based on Software Defined Radio Technique using Gnu radio/USRP

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