{'fraction_non_alphanumeric': 0.021768103065304308, 'fraction_numerical': 0.0, 'mean_word_length': 5.16986301369863, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Building blocks for multi-hop and mobile ad hoc networks with free space optics

Optical wireless, also known as free space optics (FSO) is a high bandwidth communication technology that enables information transmission through atmosphere using modulated light beams. FSO communication technology has attractive characteristics like dense spatial reuse due to light beam directionality, low power usage per bit, and license-free band of operation. FSO networks face two major challenges for deployment as general purpose metropolitan area networking or multi-hop ad hoc networks. They are: a need for the existence of line-of-sight between the communicating nodes and reduced transmission quality for adverse weather conditions. This thesis proposes new approaches in the physical and datalink layers to address above challenges and improve the link reliability. Further, motivated by higher layer issues like routing, we propose new methods of node localization and mobile tracking using FSO. These contributions are described below. Spherically shaped omnidirectional optical nodes and auto-aligning electronic circuitry is proposed and implemented as a new solution approach to address the line-of-sight alignment problem. With this, not only the auto-alignment problem is addressed, but for the first time, we demonstrated high bandwidth mobile FSO communication. This opens up the possibility of a whole new application regime for FSO technology, auto-configurable mobile ad hoc networks. Next, to address the reduced transmission quality due to adverse weather conditions, we propose to use short multiple hops of the FSO link. We analyzed the error behavior of multi-hop FSO link and showed that the error performance is better compared to a single hop link for the same end-to-end range. We also demonstrated that planar array antennas achieve high spatial redundancy/re-use provide very high aggregate bandwidth in short range FSO communication. In the data-link layer, we plan to implement suitable Forward Error Correction (FEC) codes to further increase the reliability of the FSO link. We exploit the directionality of the FSO link, and propose a new method to achieve distributed node localization in an ad hoc network. With the proposed