Browsing by Author "Kashani, Mohammadreza Amini"

Now showing 1 - 1 of 1

Embargo
Performance analysis and optimization of relay-assisted free space optical communication systems
(2012-07) Kashani, Mohammadreza Amini; Uysal, Murat; Uysal, Murat; Ercan, Ali Özer; Pusane, A. E.; Kashani, Mohammadreza Amini
Free-space optical (FSO) communication has received an increasing attention in recent years with their ability to achieve ultra-high data rates (at the order of multiple gigabits per second) over unlicensed optical spectrum. A major degrading factor, particularly in long links, is the atmospheric turbulence induced fading. Smartly exploiting the fact that fading variance is distance-dependent in FSO channel, relay assisted transmission takes advantage of the resulting shorter hops and yields significant performance improvements. In this thesis, we make several contributions to the performance analysis and design of relay-assisted FSO systems. In the first part, we investigate how to determine optimal relay locations in serial and parallel FSO relaying as to minimize the outage probability and quantify performance improvements obtained through optimal relay placement. In the second part, we investigate the combined use of serial and parallel relaying for FSO mesh networks. We derive the outage probability expressions of FSO mesh networks and demonstrate performance improvements with respect to both stand-alone serial and parallel relaying schemes. We also present a diversity gain analysis and quantify the achievable diversity orders in terms of the number of relays and turbulence channel parameters. Finally, we investigate the use of all-optical relaying removing the need for optical-electrical and electrical-optical conversions. Building on all-optical relay assumption, we investigate the outage performance of a dual-hop FSO link taking into account practical limitations such as amplifier noise and filtering effects.