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Constellation Optimization for the Non-Linear Fiber Channel
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- Author / Creator
- Soleimanzade, Amirhosein
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Due to the exponential growth of Internet usage and inefficiency of the traditional modulations, the capacity of the current optical fiber networks is not sufficient for future Internet demands. As a result, increasing the capacity of the fiber networks is of great importance. Since most of the available bandwidth of fiber systems has been occupied, improving the spectral efficiency (SE) of the fiber channel is an appropriate approach to increase the capacity. Constellation optimization (also known as constellation shaping or constellation design) is an efficient SE enhancement technique, and has two important categories: (1) probabilistic shaping and (2) geometric shaping. Probabilistic shaping changes the uniform distribution of the constellation points into a non-uniform distribution. Geometric shaping relocates the position of the equiprobable constellation points such that the achievable rate increases. In this thesis, we propose two constellation optimization methods. The first method is a geometric shaping method that maximizes mutual information (MI) of the amplitude-phase shift keying (APSK) constellations. We optimize APSK constellations for the additive white Gaussian noise (AWGN) channel and non-linear fiber channel. For the fiber channel, the optimization is performed at the maximum modified signal-to-noise ratio (SNR) of the optical system. By doing so, our optimization algorithm maximizes the MI rate while the impacts of shaping on the non-linear interference noise (NLIN) power are considered. The second shaping method is a hybrid method that combines probabilistic shaping and geometric shaping. Our hybrid method maximizes the generalized mutual information by considering the impacts of shaping on non-linear interference noise. We show that our hybrid method outperforms both geometrically and probabilistically-shaped constellations.
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- Graduation date
- Spring 2022
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.