車聯網技術透過車輛間建構的網路交換交通狀態的資料，具有可以提高道路交通的 效率與安全性的優點，近年來，已在智慧型運輸系統被廣泛的研究，例如:透過分 享各車輛所偵測到的周遭交通狀況給其他路上的車輛，具備車聯網功能的車輛可以 藉由上述資訊，來調節與控制自身車輛運行。然而，在車聯網的技術實際部署到智 慧型運輸系統時會受到兩個限制，低覆蓋率以及車載傳感器會有盲點。相較於以車 輛為中心的車聯網技術所建構之交通狀況感測系統，以路測單元為中心所建置之系 統由於可以避免上述兩個限制所帶來的影響，因此，近年來成為研究的焦點。在本 論文中，我們的目標是透過提出一個軟體框架改進以路側單元為中心的設計。此框 架可以感知交叉路口周圍的交通狀況，並將感知到的交通狀況廣播給附近的聯網車 輛。除此之外，我們同時提出了一個軟體模組降低路側單元處理多個應用時所產生 的效能衝擊。因此，聯網車輛可以在路側單元的幫助下，感知到那些未聯網或是處 於感測器盲點的車輛並進而能夠避免潛在的事故發生。我們也在設計了一系列的實 驗，測試本論文提出的軟體設計，實驗結果顯示此框架可以顯著提高交通安全，並 同時符合國際汽車工程學會定義的標準的性能規範。

While vehicle to everything technology has been proposed to improve road traffic efficiency and safety, it would suffer from the two limitations, the low coverage and the blind spots of onboard sensors, during an early stage of vehicle-to-everything deployment. The infrastructure based solutions, rather than vehicle-centric designs dictated by the vehicle-to- everything technology, have been development to tackle the problem by gathering traffic status on a roadside unit and broadcasting the detected information to nearby connected vehicles. In this work, we aim to augment such an infrastructure-centric design by proposing a software framework to perceive the surrounding traffic context of an intersection and to broadcast the sensed traffic conditions to connected vehicles in the vicinity. In addition, we propose a software module to improve the handling of multiple applications for the roadside unit. As a result, connected vehicles can be aware of those non-connected vehicles with the help of the roadside unit, which facilitates road traffic safety. We have evaluated the pro- posed software in indoor tests, which shows that the framework can significantly improve traffic safety while conforming to the performance specifications of the standards defined by Society of Automotive Engineers.

[1] G.DimitrakopoulosandP.Demestichas,“Intelligenttransportationsystems,”IEEEVe- hicular Technology Magazine, vol. 5, no. 1, pp. 77–84, 2010.
[2] K. Abboud, H. A. Omar, and W. Zhuang, “Interworking of dsrc and cellular network technologies for v2x communications: A survey,” IEEE Transactions on Vehicular Technology, vol. 65, no. 12, pp. 9457–9470, 2016.
[3] SAE J2945/1, “On-Board System Requirements for V2V Safety Communications,” April 2020.
[4] E. Moradi-Pari, D. Tian, H. Nourkhiz Mahjoub, and S. Bai, “The smart intersection: A solution to early-stage vehicle-to-everything deployment,” IEEE Intelligent Trans- portation Systems Magazine, pp. 2–17, 2021.
[5] T. Kitazato, M. Tsukada, H. Ochiai, and H. Esaki, “Proxy cooperative awareness mes- sage: an infrastructure-assisted v2v messaging,” in 2016 Ninth International Confer- ence on Mobile Computing and Ubiquitous Networking (ICMU), pp. 1–6, 2016.
[6] ETSI EN 302 637-2 V1.3.2 (2014-11), “Intelligent transport systems (its); vehicular communications; basic set of applications; part 2: Specification of cooperative aware- ness basic service,” December 2014.
[7] C.-H.Su,“Designandimplementationofroadsideunitmiddlewareforintelligenttrans- portation system applications,” 10 2021.
[8] SAE J2735, “V2X Communications Message Set Dictionary,” July 2020.
[9] J. B. Kenney, “Dedicated short-range communications (dsrc) standards in the united
states,” Proceedings of the IEEE, vol. 99, no. 7, pp. 1162–1182, 2011.
[10] D. Jiang, V. Taliwal, A. Meier, W. Holfelder, and R. Herrtwich, “Design of 5.9 ghz dsrc-based vehicular safety communication,” IEEE Wireless Communications, vol. 13, no. 5, pp. 36–43, 2006.
[11] S. Hamato, S. H. Syed Ariffin, and N. Fisal, “Overview of wireless access in vehicular environment (wave) protocols and standards,” Indian Journal of Science and Technol- ogy, vol. 7, 07 2013.
[12] K.-Y. Ho, P.-C. Kang, C.-H. Hsu, and C.-H. Lin, “Implementation of wave/dsrc de- vices for vehicular communications,” in 2010 International Symposium on Computer, Communication, Control and Automation (3CA), vol. 2, pp. 522–525, 2010.
[13] R. A. Uzcategui, A. J. De Sucre, and G. Acosta-Marum, “Wave: A tutorial,” IEEE Communications Magazine, vol. 47, no. 5, pp. 126–133, 2009.
[14] D.JiangandL.Delgrossi,“Ieee802.11p:Towardsaninternationalstandardforwireless access in vehicular environments,” in VTC Spring 2008 - IEEE Vehicular Technology Conference, pp. 2036–2040, 2008.
[15] S. Gräfling, P. Mähönen, and J. Riihijärvi, “Performance evaluation of ieee 1609 wave and ieee 802.11p for vehicular communications,” in 2010 Second International Confer- ence on Ubiquitous and Future Networks (ICUFN), pp. 344–348, 2010.
[16] H.-S. Seo, D.-G. Noh, C.-J. Lee, and S.-S. Lee, “Design and implementation of inter- section movement assistant applications using v2v communications,” in 2013 Fifth In- ternational Conference on Ubiquitous and Future Networks (ICUFN), pp. 49–50, 2013.
[17] R. Miucic, A. Sheikh, Z. Medenica, and R. Kunde, “V2x applications using collabo- rative perception,” in 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), pp. 1–6, 2018.
[18] M. Tsukada, T. Oi, A. Ito, M. Hirata, and H. Esaki, “Autoc2x: Open-source software to realize v2x cooperative perception among autonomous vehicles,” in 2020 IEEE 92nd Vehicular Technology Conference (VTC2020-Fall), pp. 1–6, 2020.
[19] S.Kato,S.Tokunaga,Y.Maruyama,S.Maeda,M.Hirabayashi,Y.Kitsukawa,A.Mon- rroy, T. Ando, Y. Fujii, and T. Azumi, “Autoware on board: Enabling autonomous vehicles with embedded systems,” in ICCPS, pp. 287–296, Apr. 2018.
[20] W.-H.LeeandC.-Y.Chiu,“Designandimplementationofasmarttrafficsignalcontrol system for smart city applications,” Sensors, vol. 20, no. 2, 2020.