Digital transmission techniques for a long haul HF link: DSSS versus OFDM

Bergadà, Pau; Alsina-Pagès, Rosa Ma; Pijoan, J.L.; Salvador, Martí; Regue, J.-R.; Badía, David; Graells, S.

doi:10.1002/2013rs005203

Cited by 31 publications

(52 citation statements)

References 28 publications

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“…These parameter results, together with our previous modulation studies [6,7], allow us to conclude that for the best hours and frequencies, high throughput modulations, like OFDM, should be used, in order to increase the bit rate of the communication. Delay spread and Doppler spread will not worsen the results in a severe way, according to the measured values.…”

Section: Discussionmentioning

confidence: 54%

“…These measurements of the long haul link improve the knowledge of the performance of the ionospheric channel that is 12,760 km long, together with previous work [4,5]. They also allow us, taking into account previous works on modulations [6][7][8], to complete the full definition of the physical layer to send the data of the remote sensors deployed across the island from Antarctica to Spain.…”

Section: Discussionmentioning

confidence: 66%

“…Finally, for sunrise, sunset and daytime, a more robust modulation should be used. The direct-sequence spread spectrum (already analyzed in [7,8]) could be a good option, assuming lower throughput, but ensuring a more robust communication against channel variations or fadings.…”

Section: Discussionmentioning

confidence: 99%

“…Since 2008, an enhanced transmitter and receiver were installed [5], and the oblique sounding observations can be widely recorded. The results presented in this paper shed light on the knowledge of this long haul link, but also help us to design the physical layer characteristics remaining from previous studies [6][7][8], where less carrier frequencies were used and the tests were not performed during the entire day. This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 91%

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Narrowband and Wideband Channel Sounding of an Antarctica to Spain Ionospheric Radio Link

et al. 2015

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La Salle and Ebro Observatory have been involved in remote sensing projects in Antarctica for the last 11 years (approximately one solar cycle). The Ebro Observatory has been monitoring and analyzing the geomagnetic and the ionospheric activity in the Antarctic Spanish station Juan Carlos I (ASJI) (62.7• S, 299.6• E) for more than eighteen and ten years, respectively. La Salle has two main goals in the project. The first one is the data transmission and reception from Antarctica to Spain to obtain a historical series of measurements of channel sounding of this 12,760-km ionospheric HF (high frequency) radio link. The second one is the establishment of a stable data low power communication system between the ASJI and Cambrils, Spain (41.0• N, 1.0 • E), to transmit the data from the remote sensors located on the island. In this paper, both narrowband and wideband soundings have been carried out to figure out the channel availability performed using a frequency range from 2 to 30 MHz with 0.5 MHz step during the 24 h of the day, encompassing wider channel measurements than previously done, in terms of hours and frequency. This paper presents the results obtained for the austral summer in 2014, using a monopole antenna at the transmitter and an inverted V on the receiver side. These results led us to the final physical layer design for the long Remote Sens. 2015, 7 11713 haul link, dividing the day into two parts: daytime, with low data throughput design, and nighttime, reaching high data throughput.

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Section: Discussionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

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Narrowband and Wideband Channel Sounding of an Antarctica to Spain Ionospheric Radio Link

et al. 2015

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“…Afterwards, the system was improved in terms of sounding frequency availability and number of soundings per day, and more complete results were evaluated in [7], giving more details on the channel parameters. Also several modulation tests using spread spectrum modulations [8] have been performed, as well as Orthogonal Frequency-Division Multiplexing (OFDM) [9] and single carrier modulations [10].…”

Section: Introductionmentioning

confidence: 99%

Physical Layer Definition for a Long-Haul HF Antarctica to Spain Radio Link

et al. 2016

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La Salle and the Observatori de l'Ebre (OE) have been involved in a remote sensing project in Antarctica for the last 11 years. The OE has been monitoring the geomagnetic activity for more than twenty years and also the ionospheric activity of the last ten years in the Spanish Antarctic Station Juan Carlos I (ASJI) (62.7 • S, 299.6 • E). La Salle is finishing the design and testing of a low-power communication system between the ASJI and Cambrils (41.0 • N, 1.0 • E) with a double goal: (i) the transmission of data from the sensors located at the ASJI and (ii) the performance of an oblique ionospheric sounding of a 12,760 km HF link. Previously, La Salle has already performed sounding and modulation tests to describe the channel performance in terms of availability, Signal-to-Noise Ratio (SNR), Doppler spread and delay spread. This paper closes the design of the physical layer, by means of the channel error study and the synchronization performance, and concludes with a new physical layer proposal for the Oblique Ionosphere Sounder. Narrowband and wideband frames have been defined to be used when the oblique sounder performs as an ionospheric sensor. Finally, two transmission modes have been defined for the modem performance: the High Robustness Mode (HRM) for low SNR hours and the High Throughput Mode (HTM) for the high SNR hours.

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Polarization diversity in a long‐haul transequatorial HF link from Antarctica to Spain

2017

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This paper describes a set of experiments which examine the feasibility of applying polarization diversity to a 12,760 km ionospheric link from Livingston Island (62.6°S, 60.4°W), South Shetlands, to Cambrils (41.0°N, 1.0°E), Spain. A transmitting monopole and both a monopole and a dipole (inverted‐V) at reception are the antennas used in this measurement campaign. Receiving antennas are orthogonal polarized to check whether wave polarization rotation causes differences between simultaneous signals. The results gathered in the paper indicate that there is a marked difference between simultaneous signals at vertical and horizontal polarized antennas, which depends on the hour of the day and the signal frequency. In this low‐throughput HF data link, polarization diversity could be used to increase SNR and performance through smart combination of receiving signals, due to the low cross‐correlation factor between them.

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Digital transmission techniques for a long haul HF link: DSSS versus OFDM

Cited by 31 publications

References 28 publications

Narrowband and Wideband Channel Sounding of an Antarctica to Spain Ionospheric Radio Link

Narrowband and Wideband Channel Sounding of an Antarctica to Spain Ionospheric Radio Link

Physical Layer Definition for a Long-Haul HF Antarctica to Spain Radio Link

Polarization diversity in a long‐haul transequatorial HF link from Antarctica to Spain

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