隨著人類需求改變與追求便利性的時代來臨，各國政府及企業無不投入資金和人才，打造可提高效率的創新應用。其中，又以智慧交通最具市場規模及成長潛力，使得運輸科技受到政府及企業兩者大力推動，車聯網便是重要發展產業之一。
車聯網（Vehicle-of-everything, V2X），意旨透過無線網路技術，讓車輛連上網際網路，與車輛（V2V）、基礎建設（V2I）、行人（V2P）或網路（V2N）進行資料雙向傳輸。過往車聯網主要採用以IEEE 802.11p為基礎的DSRC（Dedicated Short Range Communications）無線技術，然而DSRC的特性並不適合大規模、大容量的車聯網應用，故各國逐漸轉向以蜂巢式網路為主的C-V2X（Cellular V2X）。根據3GPP的技術規格指出，採用4G LTE技術之車聯網服務的延遲標準為1,000毫秒，採用5G NR技術更是提升到100毫秒，顯示低延遲特性對車聯網產業應用的重要性。
是故，為了瞭解現有系統是否符合國際標準組織對車聯網服務品質之要求，本研究結合第四代樹莓派（Raspberry Pi 4）、車載診斷系統（On-Board Diagnostics）、4G行動網路介面卡、交通號誌資料庫等，建立一個車網通訊系統（Vehicle-to-network, V2N）測試平台，在此平台上，車輛端除了可以與交通號誌資料庫連線，取得附近路網的交通號誌之即時資料之外，還能將自身車輛資訊上傳至資料庫或雲端，供個人或相關單位使用。隨後，本研究即針對整個測試平台──也就是車輛端到虛擬交控中心這段範圍──進行網路傳輸效能實測，研究結果不僅顯示本研究測試平台的網路傳輸效能符合3GPP對車聯網服務品質之要求，亦發現網路流量、路由器的數量多寡與壅塞程度等因子會影響網路傳輸效能表現。
本研究希冀透過分析車網通訊測試平台的傳輸效能，給予政府單位、事業單位、非營利組織等團體些許方向參考，未來在開發車聯網或智慧運輸相關應用時，欲達網路傳輸效能最佳化，可以將硬體網路架構配置納入系統設計的因素之一。

With the challenge for people's changing needs and pursuing convenience, governments and industries around the world have been investing heavily in innovative systems that can improve the quality of life. Smart transportation system is a key innovative system, as well as a type of fundamental infrastructure with large market scale and great growth potential, which attracting much attention of both public and private sectors. In smart transportation system, V2X (Vehicle-to-Everything) is seen as one of the most important applications. The V2X is a vehicular communication technology that supports the transmission of information from a vehicle to all nearby cars or road-side units. In fact, the V2X technology is derived from IEEE 802.11p, which is a global standard, as well as a kind of WLAN (wireless local area network) technologies.
A new technology, C-V2X (Cellular-V2X), is an alternative to IEEE 802.11p and uses LTE (long term evolution). Apart from direct communication, C-V2X allows devices to use vehicle-to-network (V2N) communication. A global and key standard, 3GPP TS 22.185, stated that an application server should support V2N application with a requirement of end-to-end delay less than 1,000 ms. This research attempts to establish a V2N-based platform by integrating Raspberry Pi 4, OBD-II (On-Board Diagnostics), virtual traffic control center, cloud, and 4G dongle. On this platform, the vehicle can connect to the traffic signal database and obtain information about traffic signals nearby. Also, it can upload its own vehicle information to the database or the cloud for further applications accessed by stakeholders or related organizations. Subsequently, this study conducts a measurement for packet delay according to the NCC (national communications and commission) regulation. We ping 100 packets with 1024 bytes from RPi-V (Raspberry Pi-Vehicle) to the virtual traffic control center and calculate average packet delay.
The research found that 1) the network transmission performance of the proposed platform meets the requirements for V2X services according to the 3GPP specification, 2) data traffic, the number of routers, and the degree of congestion can affect network transmission performance. In summary, it is essential for government, business or non-profitable organizations to take network architecture into account to improve network transmission performance, while developing the ITS applications in the future.

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