Performance Analysis of Space-Air-Ground Integrated Network (SAGIN) Over an Arbitrarily Correlated Multivariate FSO Channel
The space-air-ground integrated network (SAGIN) system interconnect several networks in order to achieve a large network topology that is capable of efficient sharing of global information and resources. Nevertheless, the associated communication facilities between the mobile platforms and air-to-ground links are limited to a low-bit rate radio-based technology. Besides, the huge services to be supported require a high capacity link in order to handle multiple information in parallel and in real-time. The free-space optical (FSO) communication system has inherent features to support the network demands. However, support for drifting in the SAGIN system could be challenging for the FSO line-of-sight links because of the requirement for alignment between the receiver and transmitter modules. Also, the FSO system performance is hindered by the atmospheric turbulence-induced fading. In addition, the unmanned aerial vehicles in the SAGIN system can operate in swarm mode to achieve system diversity in order to alleviate turbulence-induced fading. However, this can lead to channel correlation that can impair the system performance. In this paper, we consider the effect of arbitrarily correlated FSO channel on the system performance. To achieve this, we employ exponential model for modeling the correlations between the apertures. Furthermore, to account for the spatial correlation in the air-to-ground as well as air-to-air communications in the SAGIN system, we consider a multivariate Gamma–Gamma (\(\varGamma \varGamma\)) distribution. The results of the study sufficiently quantify the effects of the atmospheric turbulence-induced fading as well as correlation on the system.
KeywordsAtmospheric turbulence Correlation Free-space optical (FSO) communication Gamma–Gamma distribution High altitude platforms (HAPs) Positioning Spatial diversity Tracking Unmanned aerial vehicles (UAV)
This work was supported in part by the Fundaçõo para a Ciência e a Tecnologia under the Ph.D. Grant PD/BD/52590/2014, in part by the European Regional Development Fund (FEDER), through the Regional Operational Programme of Centre (CENTRO 2020) of the Portugal 2020 framework [Project HeatIT with Nr. 017942 (CENTRO-01-0247-FEDER-017942)] and by the FCT/MEC through the national funds under the project, COMPRESS - PTDC/EEI-TEL/7163/2014, in part by the Integrated Programmes “SOCA” (CENTRO-01-0145-FEDER-000010) and “ORCIP” (POCI-01-0145-FEDER- 022141) co-funded by Centro 2020 Program, Portugal 2020, European Union, through the European Regional Development Fund, and in part by the FEDER, through the Competitiveness and Internationalization Operational Programme (COMPETE 2020) of the Portugal 2020 framework , Project, RETIOT, POCI-01-0145-FEDER-016432.
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