Recently, free space optical communication has attracted a considerable amount of interest as an alternative medium to
radio for wireless transmission. It has many advantages such as a huge unregulated bandwidth, high data rates, and
resistance to multi-path fading relative security against eavesdropping. The work presented in this thesis focuses on
modulation schemes. Concerns of eye safety and power consumption limit the average transmitter power, which suggests
that modulation techniques possessing a high peak-to-mean power ratio are favorable. This is generally achieved by
trading off power efficiency against bandwidth efficiency. A novel dual-header pulse interval modulation (DH-PIM) for
optical wireless communications is proposed in this paper. The symbol structure, the spectral properties, and the
expression for bandwidth requirement and optical power requirement of DH-PIM in the absence of and in the presence
of multi-path dispersion is presented in this paper.
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