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Performance Investigations of Filtered Carrier Phase Estimator for High-Order QAM Systems
Students: Shay Tzubery , Sapir Todosi
Supervisor: Dr. David Dahan
להסבר מוקלט
Introduction
- The data traffic pace is experiencing dramatic growth in an era where end-users consume apps, services, and visual contents online.
- Optical networks can cope with the exponential growth of data traffic by using higher order QAM modulation at high baud rate.
- The main goal of this project is to apply and investigate digital and blind carrier phase estimation and compensation methods based on Viterbi & Viterbi estimators adapted to the high-order QAM method and enables the reduction of cycle slips occurrences.
- The project implements part of the DSP of a coherent optical receiver.
Model & Algorithms
- Discrete channel model with Phase noise & AWGN noise:
- Viterbi and Viterbi (V&V*) for 64QAM modulation:
- Phase estimation steps according to the MLE algorithm:
Cycle slips problem & Differential Encoding
In the occurrence of CS, the synchronization between the decision areas we define and the symbols we receive is completely lost.
In Differential Encoding , some information bits are encoded on the phase difference between two consecutive symbols: this mitigates cycle slips impact.
Simulation Results
Conclusions
We have developed a numerical simulation platform to evaluate the performance of a high speed 64-QAM coherent optic receiver based on Blind Carrier Phase Estimation algorithm to reduce impact of laser phase noise and cycle slips.
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