
近年、遠隔会議や車載テレオペレーション、クラウドARといったリアルタイム通信アプリケーションの需要が急速に高まる中、通信インフラの安定性と品質が重要な研究課題となっています。特に5Gは次世代の通信基盤として期待されていますが、場所や時間帯による通信品質のばらつきが課題とされています。塚田研究室では、こうした課題に対応するために、複数のモバイル回線を同時に活用する「マルチパス冗長通信フレームワーク」の開発に取り組んでいます。
本プロジェクトでは、UDPベースのWebRTCによるリアルタイムストリーミングを対象とし、従来のTCP中心のマルチパス手法が持つ課題を克服する新たなアーキテクチャを提案しました。IPレイヤにおけるトンネリング技術と受信側での再整列バッファリング機構を導入することで、パケット順序の不整合を吸収しながら安定したストリーミングを実現しています。都市内で移動する車両上に複数の回線を構築し、現実環境で実験を行った結果、パケットロスの大幅な低減とビットレートの向上が確認されました。
さらに、実際の5Gネットワーク環境下でのQoS(Quality of Service)評価も行いました。通信キャリアや周波数帯、地理条件、ハンドオーバー、移動速度などの変数と通信品質の相関を分析し、WebRTCベースの協調アプリケーションにおける性能変動の実態を可視化しました。本研究は5Gの実用性に対する新たな洞察を提供するとともに、得られたデータを公開することでQoS研究の基盤を構築しています。
これらの成果は、今後のリモートコラボレーション、モバイルXR、車載通信、災害対応通信基盤などへの応用が期待されています。マルチパス通信とリアルタイムメディア処理の融合により、可用性と品質を両立した次世代モバイル通信インフラの構築を目指します。
@article{ITO2025108157,
title = {A multipath redundancy communication framework for enhancing 5G mobile communication quality},
author = {Koki Ito and Jin Nakazato and Romain Fontugne and Manabu Tsukada and Hiroshi Esaki},
url = {https://www.sciencedirect.com/science/article/pii/S0140366425001148},
doi = {https://doi.org/10.1016/j.comcom.2025.108157},
issn = {0140-3664},
year = {2025},
date = {2025-04-23},
urldate = {2025-04-23},
journal = {Computer Communications},
pages = {108157},
abstract = {As networks increasingly become the backbone of modern society, the demands placed on them by various applications have become more complex. In particular, the demand for high-capacity, low-latency services such as real-time streaming is increasing every year. Although 5G has been deployed to meet these needs, its effectiveness can vary significantly by location and time, and sometimes falls short of requirements. Traditionally, much of the research to improve communication stability has focused on TCP-based systems, which do not translate well to real-time UDP streaming applications. To address the above challenges, we propose a multipath redundant communication framework designed to improve the quality of real-time media streaming. This framework has been tested using multipath redundant communication over two mobile networks with a moving vehicle in an urban environment. Using a real-time streaming application based on WebRTC, our framework demonstrates a significant reduction in packet loss and an increase in bitrate, outperforming existing multipath redundant communication systems without interfering with the application’s congestion control mechanisms.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
@inproceedings{Ito2024,
title = {Enhancing Real-Time Streaming Quality through a Multipath Redundant Communication Framework},
author = {Koki Ito and Jin Nakazato and Romain Fontugne and Manabu Tsukada and Hiroshi Esaki},
doi = {10.23919/IFIPNetworking62109.2024.10619885},
year = {2024},
date = {2024-06-03},
urldate = {2024-06-03},
booktitle = {IFIP/IEEE Networking 2024},
address = {Thessaloniki, Greece},
abstract = {Recently, as networks operate as the infrastructure of modern society, the demands placed on the network by applications have become more complex. In particular, an increasing annual demand for high-capacity and low-latency services, including real-time streaming. 5G services have been launched to meet this demand, but their stability varies de- pending on location and time and can only sometimes be considered sufficient. One method to improve communication stability is multipath redundant communication, and much research has been conducted in this area. However, most of this research has focused on TCP-based communication and cannot be applied to real-time UDP streaming. Hence, we propose a multipath redundant communication framework to improve the quality of real-time media streaming communication. Tunneling at the IP layer in our proposed framework was performed to overcome the limitations of transport layer protocols, which was a challenge for traditional multipath redundant communication systems. Furthermore, to address the packet order inconsistency caused by multipath redundant communication, a buffering mechanism was implemented on the receiving side of our system. Our proposed system was verified using multipath redundant communication and multiple mobile networks from a vehicle moving in an urban area. The experiments used a real-time streaming application based on WebRTC, and the framework significantly reduced packet loss and improved bitrate compared to existing multipath redundant communication systems without interfering with the application’s congestion control.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
@article{Nakazato2023,
title = {WebRTC over 5G: A Study of Remote Collaboration QoS in Mobile Environment},
author = {Jin Nakazato and Kousuke Nakagawa and Koki Ito and Romain Fontugne and Manabu Tsukada and Hiroshi Esaki},
url = {https://link.springer.com/content/pdf/10.1007/s10922-023-09778-5.pdf},
doi = {10.1007/s10922-023-09778-5},
issn = {1573-7705},
year = {2023},
date = {2023-10-24},
urldate = {2023-10-24},
journal = {Journal of Network and Systems Management},
volume = {32},
issue = {1},
abstract = {The increasing demand for remote collaboration and remote working has become crucial to daily life owing to the Covid-19 pandemic and the development of internet-based video distribution services. Furthermore, low-latency remote collaboration, such as teleoperation and support applications designed for in-vehicle environments, has gained considerable attention. The 5G technology is considered as a key infrastructure for remote collaboration. This study aimed to evaluate the actual 5G capability to achieve high quality of service (QoS) for remote collaboration. We designed and implemented a measurement tool to monitor the QoS of remote collaboration under real-world 5G conditions. We performed measurements encompassing the various 5G frequency bands. During these experiments, we employed various tools to obtain detailed mobile signal conditions to analyze the relationship between various environmental factors (e.g. signal quality, band, handoff, geographic conditions, and mobility) and the QoS performance of remote collaboration in a real-world 5G environment. This study elucidated the correlation between the WebRTC performance and various environmental factors as well as the performance improvement potential by leveraging the communication technologies of multiple mobile carriers. The collected data has been made publicly available to foster research on QoS and 5G.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
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