Multi-Hop Relaying over the Atmospheric Poisson Channel: Outage Analysis and Optimization

• Published in: IEEE transactions on communications Vol. 60; no. 3; pp. 817 - 829
• Main Authors: Safari, M., Rad, M. M., Uysal, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Access methods and protocols, osi model; Applied sciences; Exact sciences and technology; Fading; free-space optical communication; Minimization; multi-hop transmission; Mutual information; Optical telecommunications; Optical transmitters; Optimization; outage probability; Poisson channel; power allocation; Power control; Radiocommunications; Receivers; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; Transmitters. Receivers; Wireless optical communications; Performance evaluation; Optical links; Relaying; Outage; multi-hop transmission; Optical telecommunication; Control system; Wireless telecommunication; Transmission protocol; Transmitter; Power allocation; Optimization; Multihop network; Optimal strategy; outage probability; Free space propagation; Atmospheric turbulence; Power control; Optimal control; Routing protocols; free-space optical communication; Free space optics; Peak power; Poisson channel
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2012.010512.100630

In this paper, we study the outage behavior of a decode-and-forward multi-hop free-space optical (FSO) system over a Poisson channel degraded by atmospheric turbulence. We assume that perfect channel side information (CSI) is available at the receiver side and consider both cases of perfect CSI and no CSI at the transmitter side. We solve the outage probability minimization problem subject to a peak power constraint as well as a short- or long-term average sum power constraint. As a result, optimal power control strategies are presented for different scenarios under consideration. A sub-optimal yet low-complexity solution is further proposed under the short-term power constraint. Our results demonstrate that multi-hop relaying yields significant performance improvements which are particularly important for long-range FSO links.