{"created":"2023-06-20T15:11:16.217914+00:00","id":7667,"links":{},"metadata":{"_buckets":{"deposit":"f6b9178d-bb2f-47ae-a0db-532e772a5c7f"},"_deposit":{"created_by":17,"id":"7667","owners":[17],"pid":{"revision_id":0,"type":"depid","value":"7667"},"status":"published"},"_oai":{"id":"oai:ynu.repo.nii.ac.jp:00007667","sets":["495:498"]},"author_link":["31856","31857","31855"],"item_7_alternative_title_21":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"情報源の統計的性質を利用したクロスレイヤ通信システム設計"}]},"item_7_biblio_info_8":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2016-09-16","bibliographicIssueDateType":"Issued"}}]},"item_7_date_granted_66":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2016-09-16"}]},"item_7_degree_grantor_64":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"横浜国立大学"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"12701","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_7_degree_name_63":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士(工学)"}]},"item_7_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"By Shannon’s separation theorem, the combination of independently optimized source coding and channel coding systems can achieve the optimal rate-distortion (R-D) relationship. Most conventional communication systems for multimedia data are modeled based on this theorem, and each technique is developed and optimized independently. However, this theorem is based on the ideal assumption that code length is infinite, and thus a practical system in real life does not conform to it. Joint source-channel coding (JSCC) is a technique to design an optimal system in terms of R-D function or computational complexity considering practical situations, e.g., finite code lengths and bit errors occurring in communications channel. It could be also stated that JSCC may lead to the breakthrough in the development of multimedia data transmission systems considering the fact that the individual studies on source coding and channel coding are reaching maturity. Unequal error protection (UEP) is a fundamental technique generally implemented in JSCC. The code rates in the framework of UEP can be optimized such that the received source quality is maximized. Most conventional studies on UEP assume that the channel state information is available at the transmitter side such that the code rate can be adjusted depending on the channel. However, this approach increases computational overhead at the transmitter. Furthermore, such an assumption is not applicable to the broadcasting systems where UEP property is most beneficial. This dissertation tackles the problems involving source and channel coding as described above by designing communication systems over the layers specified by the Open Systems Interconnection (OSI) reference model, where the source coding process corresponds to the application (or upper) layer design whereas the channel coding is implemented in the physical layer. Chapter 1 is dedicated to a literature review on JSCC, and some major issues in the past studies are identified. Chapter 2 describes source coding characteristics observed in modern source compression techniques. An application of image transmission in combination with UEP is also presented as a specific example. Chapter 3 derives the achievable R-D function by JSCC system compared to separately designed source and channel coding system over AWGN channel with a specific channel SNR. The design of JSCC system is applied to the combination of subband coded audio signal and rate compatible punctured convolutional (RCPC) codes as a simple example. In Chapter 4, a novel coded modulation system design that maximizes the average quality of multimedia data, received by a given set of target users, is proposed for compressed video broadcasting based on UEP. To this end, a new measure is introduced that describes the received video quality averaged over the users located within the coverage area of a given broadcasting service. In Chapter 5, from the viewpoint of physical layer implementation, a novel decoding technique is introduced that improves the throughput of the system by exploiting inherent padding bits in the transmitted sequence as a consequence of the mismatch between the length of channel coding frame and that of the source coding. This improvement is achieved by trellis pruning in the decoding process of turbo code. The proposed decoder has the detector of padding bits, and thus the side information about the insertion of padding bits is unnecessary at the receiver. Finally, the conclusion is given in Chapter 6.","subitem_description_type":"Abstract"},{"subitem_description":"シャノンの情報源・通信路分離定理により、それぞれ独立に最適化された情報源符号化と通信路符号化の組み合わせが最適なレート・歪み(R-D: Rate-Distortion) 特性を示すことが証明されている。従来の多くのマルチメディアデータの通信システムはこの理論に則って設計されており、各々の技術は独立に最適化が試みられている。しかしながら、この理論は符号が無限の長さを持つという理想的な仮定に基づいているため、必ずしも現実のシステムの最適性を保証するものではない。そこで近年、情報源・通信路結合符号(JSCC: Joint Source-Channel Coding) が注目されている。これは、有限長の符号や通信路で生じるビット誤りなど現実的な制約を考慮して、R-D 特性や計算複雑度の観点から最適なシステムを設計する技術である。情報源符号化と通信路符号化の各分野に閉じた研究開発が成熟しつつある現在、JSCC はマルチメディアデータの伝送システムの研究において大きな発展をもたらすものと考えられる。不均一誤り訂正(UEP: Unequal Error Protection) は一般にJSCC で用いられる要素技術である。UEP では、通常符号化率の最適化は受信側での情報源の復号品質が最大になるように行われる。従来のUEP に関する多くの研究においては、送信器側で通信路状態が既知であるという仮定がなされており、通信路に合わせて符号化率を調整する手法が採用されているが、送信器側で必要となる演算量が大きくなるという問題がある。さらにこの仮定は、UEP の応用として有力である放送システムには適用できない。本論文では、OSI 参照モデルにおけるレイヤーを縦断した通信システムを設計することにより、上記のような情報源符号化と通信路符号化に関連する問題に取り組む。OSI 参照モデルでは、情報源符号化の過程はアプリケーション層(または上位層) に相当し、通信路符号化は物理層内で実装される。第1 章ではJSCC に関する研究動向について述べ、過去の研究の問題点を明らかにする。第2 章では近代のデータ圧縮技術で見られる情報源符号化の特徴を説明する。また、一例としてUEP を画像伝送に適用したシステムについての検証も行う。第3 章では、あるチャネルSNR を持つAWGN 通信路においてJSCC によって達成できるR-D 特性を、情報源符号化と通信路符号化を独立して設計したシステムによるR-D特性と比較する。簡単な例としてサブバンド符号化されたオーディオ信号とパンクチャド畳み込み符号を組み合わせたシステムを用いてJSCC の設計を行う。第4 章では、圧縮された動画像を送信する放送システム向けに、サービス対象とするユーザ群が受信する映像の平均品質を最大化する符号化変調システムの設計指針を提案する。ここでは放送サービスのカバレッジ範囲内のユーザの平均的なビデオの受信品質を表す新たな指標を導入する。第5 章では、情報源符号化と通信路符号化のフレーム長の不一致を補填する目的で一般に広く導入されるパディングビットを受信側での誤り訂正符号の復号に活用することで、従来システムに比べて通信システムのスループットを向上させることが可能であることを示す。この特性向上はターボ符号の復号過程においてトレリスプルーニングを用いることで達成される。なお、提案する復号器にパディングビットの検出器を備えることで、パディングビットの挿入に関するサイド情報の送信が不要となる。最後に第6 章において結論を述べる。","subitem_description_type":"Abstract"}]},"item_7_dissertation_number_67":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第1852号"}]},"item_7_full_name_2":{"attribute_name":"著者(ヨミ)","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"31856","nameIdentifierScheme":"WEKO"}],"names":[{"name":"ワタナベ, ヨシト"}]}]},"item_7_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"31857","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Watanabe, Yoshito"}]}]},"item_7_subject_24":{"attribute_name":"国立国会図書館分類","attribute_value_mlt":[{"subitem_subject":"UT51","subitem_subject_scheme":"NDLC"}]},"item_7_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"Graduate School of Engineering, Yokohama National University"}]},"item_7_version_type_18":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"渡辺, 良人"}],"nameIdentifiers":[{"nameIdentifier":"31855","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-02-17"}],"displaytype":"detail","filename":"watanabe_yoshito-thesis.pdf","filesize":[{"value":"1.7 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"watanabe_yoshito-thesis.pdf","objectType":"fulltext","url":"https://ynu.repo.nii.ac.jp/record/7667/files/watanabe_yoshito-thesis.pdf"},"version_id":"ff57f2e0-2e4a-47d2-9e9e-44f944f772f1"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-02-17"}],"displaytype":"detail","filename":"watanabe_yoshito-review.pdf","filesize":[{"value":"185.6 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"watanabe_yoshito-review.pdf","url":"https://ynu.repo.nii.ac.jp/record/7667/files/watanabe_yoshito-review.pdf"},"version_id":"8e2dd52a-864d-4aeb-84d2-582389ae4511"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Cross-layer communication system designs exploiting statistical property of sources","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Cross-layer communication system designs exploiting statistical property of sources","subitem_title_language":"en"}]},"item_type_id":"7","owner":"17","path":["498"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2017-02-17"},"publish_date":"2017-02-17","publish_status":"0","recid":"7667","relation_version_is_last":true,"title":["Cross-layer communication system designs exploiting statistical property of sources"],"weko_creator_id":"17","weko_shared_id":-1},"updated":"2023-08-25T01:42:30.747592+00:00"}