{"id":{"repo_id":"nus","oai_identifier":"oai:scholarbank.nus.edu.sg:10635/53623"},"canonical_url":"https://search.dev.ndltd.org/etd/nus/oai:scholarbank.nus.edu.sg:10635/53623","repository":{"repo_id":"nus","name":"National University of Singapore","base_url":"https://scholarbank.nus.edu.sg/oai/request"},"display":{"title":"Digital Signal Processing for Front-end Non-idealities in Coherent Optical OFDM system","abstract":"In this thesis, we propose digital signal processing algorithms for combatting the front-end non-idealities in CO-OFDM systems, including carrier frequency offset, linear phase noise and IQ mismatch. Firstly, we propose a novel frequency offset compensation method, which is successfully demonstrated through experiment. Our algorithm achieves the widest estimation range with one training symbol. Secondly, we propose a novel decision-aided phase estimation method and its combination with pilot-aided and decision feedback methods to compensate for common phase error induced by linear phase noise. Furthermore, a modified time-domain blind algorithm is proposed for mitigating the intercarrier interference induced by linear phase noise in CO-OFDM system with non-constant amplitude modulation formats. Thirdly, we propose a decision-aided joint compensation method for Tx IQ mismatch and channel distortion. Lastly, we analytically derive new LLR with linear phase noise term for LDPC coded OFDM system with different modulation formats: differential MPSK, pilot-aided MPSK and pilot-aided M-QAM.","abstract_html":"In this thesis, we propose digital signal processing algorithms for combatting the front-end non-idealities in CO-OFDM systems, including carrier frequency offset, linear phase noise and IQ mismatch. Firstly, we propose a novel frequency offset compensation method, which is successfully demonstrated through experiment. Our algorithm achieves the widest estimation range with one training symbol. Secondly, we propose a novel decision-aided phase estimation method and its combination with pilot-aided and decision feedback methods to compensate for common phase error induced by linear phase noise. Furthermore, a modified time-domain blind algorithm is proposed for mitigating the intercarrier interference induced by linear phase noise in CO-OFDM system with non-constant amplitude modulation formats. Thirdly, we propose a decision-aided joint compensation method for Tx IQ mismatch and channel distortion. Lastly, we analytically derive new LLR with linear phase noise term for LDPC coded OFDM system with different modulation formats: differential MPSK, pilot-aided MPSK and pilot-aided M-QAM.","abstract_has_math":false,"creators":["CAO SHENGJIAO"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-01-17","date_published":"2014-01-17","updated_at":"2026-07-24T03:33:22Z","subjects":["coherent optical communication, OFDM, carrier frequency offset, linear phase noise, IQ mismatch, LDPC"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["CAO SHENGJIAO"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2014-01-17"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://scholarbank.nus.edu.sg/handle/10635/53623"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["coherent optical communication, OFDM, carrier frequency offset, linear phase noise, IQ mismatch, LDPC"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://scholarbank.nus.edu.sg/bitstreams/76264222-8af1-4118-95af-22cca60266b5/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In this thesis, we propose digital signal processing algorithms for combatting the front-end non-idealities in CO-OFDM systems, including carrier frequency offset, linear phase noise and IQ mismatch. Firstly, we propose a novel frequency offset compensation method, which is successfully demonstrated through experiment. Our algorithm achieves the widest estimation range with one training symbol. Secondly, we propose a novel decision-aided phase estimation method and its combination with pilot-aided and decision feedback methods to compensate for common phase error induced by linear phase noise. Furthermore, a modified time-domain blind algorithm is proposed for mitigating the intercarrier interference induced by linear phase noise in CO-OFDM system with non-constant amplitude modulation formats. Thirdly, we propose a decision-aided joint compensation method for Tx IQ mismatch and channel distortion. Lastly, we analytically derive new LLR with linear phase noise term for LDPC coded OFDM system with different modulation formats: differential MPSK, pilot-aided MPSK and pilot-aided M-QAM."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["72ba554e02d32134f52c4e1ba798e214","fc1e0a6d03e83be9944c8b6358de73d0"]},{"key":"dc:title","label":"Title","values":["Digital Signal Processing for Front-end Non-idealities in Coherent Optical OFDM system"]}]}],"canonical_facts":{"dc:creator":["CAO SHENGJIAO"],"dc:date.issued":["2014-01-17"],"dc:description.abstract":["In this thesis, we propose digital signal processing algorithms for combatting the front-end non-idealities in CO-OFDM systems, including carrier frequency offset, linear phase noise and IQ mismatch. Firstly, we propose a novel frequency offset compensation method, which is successfully demonstrated through experiment. Our algorithm achieves the widest estimation range with one training symbol. Secondly, we propose a novel decision-aided phase estimation method and its combination with pilot-aided and decision feedback methods to compensate for common phase error induced by linear phase noise. Furthermore, a modified time-domain blind algorithm is proposed for mitigating the intercarrier interference induced by linear phase noise in CO-OFDM system with non-constant amplitude modulation formats. Thirdly, we propose a decision-aided joint compensation method for Tx IQ mismatch and channel distortion. Lastly, we analytically derive new LLR with linear phase noise term for LDPC coded OFDM system with different modulation formats: differential MPSK, pilot-aided MPSK and pilot-aided M-QAM."],"dc:format.checksum.md5":["72ba554e02d32134f52c4e1ba798e214","fc1e0a6d03e83be9944c8b6358de73d0"],"dc:identifier.uri":["https://scholarbank.nus.edu.sg/bitstreams/76264222-8af1-4118-95af-22cca60266b5/download"],"dc:relation.isreferencedby":["https://scholarbank.nus.edu.sg/handle/10635/53623"],"dc:subject":["coherent optical communication, OFDM, carrier frequency offset, linear phase noise, IQ mismatch, LDPC"],"dc:title":["Digital Signal Processing for Front-end Non-idealities in Coherent Optical OFDM system"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T03:33:22Z"}