| 摘要: | 本論文主要討論車載通訊與智慧交通運輸系統的橫向整合應用。由資通訊系統的規格制定與設備驗證、收發機設計到整合資通訊設備並佈建實際智慧型交通運輸系統；藉由軟體模擬以及實車驗證研發適合的技術。
本論文第一章針對車載通訊與智慧型交通運輸系統的關聯性以及過去研究與未來發展做討論。以通訊技術發展為主軸，對車間與車對路側基地台之間的資料傳輸關係進行技術分析。
第二章主要討論規格制定與測試環境；先對於車載通訊系統的無線通道進行討論接著討論設備驗證工作時的實車、實場測試流程，最後從測試結果對照理論模擬進行討論。
第三章則是針對車載通訊系統收發機設計進行研究，根據現有IEEE 802.11p所使用的OFDM技術的不足部分進行延伸，並且討論多種被提出的OFDM相關技術。針對這些被廣泛提出的技術並且參考中國大陸的TDS-OFDM 技術設計出適合在車載系統上運作的Data-aidded OFDM (DA-OFDM)系統。
第四章則是將在第三章中所提出的DA-OFDM技術應用在智慧型交通運輸系統上。在多路側基地台(Roadside Unit, RSU)的環境下，討論換手問題，並且針對換手最基本也是第一個發生的路側基地台的搜尋及辨識問題進行討論。
因為DA-OFDM與過去設計不同，並且TDS-OFDM對訊號接收與同步的研究也不完整，所以本文修正被普遍採用的Beek’s ML estimation技術使其可以使用在DA-OFDM上，並且也利用這個同步技術建立路側基地台的搜尋及辨識方法。
Next-generation Telematics solutions are being driven by the maturation of recently deployed intelligent transportation systems (ITSs), assisted by the integration of and rapid collaboration with information communication technology (ICT) markets and the utomotive industry. Examples of this trend can be found in Dedicated Short-Range Communication (DSRC) contexts where wireless communication techniques have become significantly relevant in vehicular environments.
In this dissertation, three topics are covered:
The first topic is focused on Comprehensive field trials. In this section, several procedures are conducted and relevant measurements are collected in physical environments to investigate the possible environmental factors that occur in vehicle-to-roadsideinfrastructure (V2I) communication scenarios. In these carefully controlled automobile experiments, the most representative parameters are measured and analyzed for DSRC in dynamic environments, e.g., packet loss, latency and delay spread. Using a systematic testing procedure and thorough measurement analysis, the communication performance and operating reliability of wireless communications can be effectively verified
insightful improvements, helpful suggestions and additional contributions may thus be derived for Telematics system designs. Furthermore, a practical, reasonable, standardized testing procedure is proposed that can be utilized in equipment verification and product certification.
Transceiver structure is covered as the second topic. Frequency errors and imperfect channel estimations (CE) are severe issues that occur in conventional systems that completely follow the current IEEE 802.11p standard. This research investigates novel techniques for conducting accurate frequency offset compensations and effective CEs. More recently, data-aided orthogonal frequency-division multiplexing (DA-OFDM) communications such as Pseudo-Random-Postfix OFDM (PRP-OFDM) and Time-Domain-Synchronous OFDM (TDS-OFDM) have been the focus of research because of their higher effectiveness, efficiency and transmission quality.
Roadside unit (RSU) selection is examined as the third topic. In the conventional IEEE 802.11p standard, the handover procedure is based on the Mobile IP technique. However, this technique is inefficient in a high-mobility environment. In this research, RSU selection (which uses a similar idea from mobile/cellular communications) is proposed to improve handover speed. |
