A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem. (April 2021)

• Record Type: Journal Article
• Authors: Singh, Surinder; Crispo, Mark; Bousquet, Jean-François; Aljendi, Shadi
• Is Part Of: International journal of distributed sensor networks. Volume 17:Number 4(2021)
• Publication Date: 2021-04
• Subjects: Software-defined modem -- underwater communications -- multiple-input multiple-output -- channel characterization -- field-programmable gate arrays; Sensor networks -- Periodicals; Intelligent agents (Computer software) -- Periodicals; Multisensor data fusion -- Periodicals; 681.2
• DOI: 10.1177/15501477211010663
• Languages: English
• ISSNs: 1550-1329

Abstract

This article describes the implementation of a multiple-input multiple-output acoustic communication link in shallow water conditions to enable a software-defined acoustic modem with a maximum transmission rate of 20 kbps in a 5-kHz bandwidth. The reliability improvement of a low-complexity Alamouti space–time block code is evaluated to improve the diversity in a high-rate transmission mode using single carrier modulation, as well as in a low-rate transmission mode relying on continuous-phase frequency-shift keying. Using measurements in realistic subsea conditions, the effect of the spatial channel correlation is demonstrated. It is found that for the space–time block code/continuous-phase frequency-shift keying, the spatial diversity is significantly degraded due to the high spatial correlation. In contrast, for the high-mode transmission rate, space–time block code with single carrier modulation offers a bit error rate improvement by a factor over hundred, in comparison to a single transmit element, demonstrating that the multiple-input multiple-output optimal code depends on the software-defined acoustic modem transmission mode.