Requirements on channel probes for automatic channel selection

Cannon, Paul S.; Angling, Matthew; Willink, T.J.; Moreland, W. C.; Davies, N.C.; Lundborg, Bengt; Jodalen, V.; Bromss, M.

doi:10.1049/ic:19960139

Cited by 10 publications

(3 citation statements)

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“…Initial results measuring multipath, Doppler spread and Doppler shift with the whole system were presented in References [35,37]. The work presented in Reference [38] justifies the necessity of using an Automatic Radio Control System (ARCS) to select the best waveform to obtain a high data rate with an acceptable bit error rate, this analysis was done illustrating the range of Doppler shifts and spreads on a adverse high latitude HF channel.…”

Section: Results and Conclusionmentioning

confidence: 99%

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Hervás

Bergadà

Alsina-Pagès

2020

Sensors

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High Frequency (HF) communications through ionospheric reflection is a widely used technique specifically for maritime, aeronautical, and emergency services communication with remote areas due to economic and management reasons, and also as backup system. Although long distance radio links can be established beyond line-of-sight, the availability, the usable frequencies and the capacity of the channel depends on the state of the ionosphere. The main factors that affect the ionosphere are day-night, season, sunspot number, polar aurora and earth magnetic field. These effects impair the transmitted wave, which suffers attenuation, time and frequency dispersion. In order to increase the knowledge of this channel, the ionosphere has been sounded by means of narrowband and wideband waveforms by the research community all over the world in several research initiatives. This work intends to be a review of remarkable projects for vertical sounding with a world wide network and for oblique sounding for high latitude, mid latitude, and trans-equatorial latitude.

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Section: Results and Conclusionmentioning

confidence: 99%

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Hervás

Bergadà

Alsina-Pagès

2020

Sensors

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“…However, more typical values are 2 milliseconds (ms) and 1 Hz, respectively, which are the basic parameters of the standardized ITU Mid-Latitude Disturbed Channel [6]. However, higher values are possible where up to 10 ms of delay spread and 50 Hz of Doppler spread have been measured [7] [8]. Table 1 presents three standardized channels proposed by the ITU [6].…”

Section: Hf Channelmentioning

confidence: 99%

“…For completeness, an example of the above model is provided in equations (7) and (8). These equations were measured for a real PA using some commercially available test equipment.…”

Section: Rf Power Amplifiersmentioning

confidence: 99%

Investigating the effects of filtering, clipping, and power amplification on the performance of OFDM waveforms

Nieto

2009

Wireless Sensing and Processing IV

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Orthogonal Frequency Division Multiplexing (OFDM) has become a very popular technique for digital data transmission on multipath fading channels due to its low computational complexity and simple equalization process. However, the multipath component of these types of channels causes a phenomenon known as frequency selective fading. This type of fading can severely degrade or completely eliminate the signal energy of many of the OFDM tones producing an irreducible error rate, even when no noise is present. Consequently, most OFDM systems operating in multipath fading environments utilize some form of forward error correction (FEC) and block interleaving. OFDM waveforms which utilize FEC are usually referred to as coded OFDM (COFDM). One of the main drawbacks of OFDM and COFDM waveforms is the very large peak envelope power to average power ratio (PAPR) which requires the use of very linear power amplifiers (PA) and a large power back-off into the PA. To reduce the PAPR, clipping is typically utilized. In addition, filtering must be applied to OFDM and COFDM waveforms in order to contain their spectral occupancy. This paper will investigate the effects of filtering, clipping and power amplification on the performance of OFDM and COFDM waveforms. The multipath fading channels used for testing will be based on the High Frequency (HF) channels due to their challenging nature.

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An investigation of coded OFDM and CEOFDM waveforms utilizing different modulation schemes on HF channels

Nieto¹

2008

2008 6th International Symposium on Communication Systems, Networks and Digital Signal Processing

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Constant Envelope Orthogonal Frequency Division Multiplexing (CE-OFDM) is a modification to OFDM which eliminates the large Peak power to AveragePower Ratio (PAPR) inherent in OFDM. For uncoded waveforms, CE-OFDM has been shown to offer some significant performance advantages over OFDM on High Frequency (HF) multipath fading channels. However, when coding and interleaving are added to the waveforms, OFDM outperforms CE-OFDM on HF multipath fading channels, even after the PAPR of OFDM is included in the performance comparison. The results presented so far have only been for 2-ary Phase Shift Keying (2-PSK) modulation. This paper will extend previous research by investigating the performance of coded OFDM and CE-OFDM waveforms using higher-order modulation schemes on various HF multipath fading channels.

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Requirements on channel probes for automatic channel selection

Cited by 10 publications

References 0 publications

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Ionospheric Narrowband and Wideband HF Soundings for Communications Purposes: A Review

Investigating the effects of filtering, clipping, and power amplification on the performance of OFDM waveforms

An investigation of coded OFDM and CEOFDM waveforms utilizing different modulation schemes on HF channels

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