<p> Wireless optical communication systems have the potential of establishing secure high
data rate communication links. In order to realize the ultimate promise of these links,
channel modeling and communication algorithms must be developed. This thesis
addresses free-space optical (FSO) system design and provides novel contributions
in four major areas: 1) channel modeling, 2) channel capacity and optimal signal
design, 3) signaling algorithms, and 4) formal methods to jointly design code rate
and beamwidth for FSO systems.</p> <p> A novel statistical channel model taking into account atmospheric and misalignment fading is developed that generalizes the existing models and accounts for transmitter beamwidth. The channel capacity is analyzed under average and peak optical power constraints and a new class of non-uniform discrete input distributions are developed with mutual information that closely approaches the channel capacity. Algorithms to realize the proposed non-uniform signaling and achieve the promising
rates are also presented. Numerical simulations are conducted with finite length low
density parity check codes showing significant improvement in system performance.
Finally, the developed signaling is applied to FSO channels considering the above
impairments. Beamwidth optimization is considered to maximize the channel capacity
subject to outage. It is shown that a rate gain of 80% can be achieved with
beamwidth optimization.</p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/17387 |
| Date | January 2009 |
| Creators | Youssef, Ahmed A. Farid |
| Contributors | Hranilovic, Steve, Electrical and Computer Engineering |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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