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車輛定位與電子地圖整合服務 Vehicle Positioning, Digital Maps and Integrated Services

車輛定位與電子地圖整合服務 Vehicle Positioning, Digital Maps and Integrated Services. Lecture 7 WAVE Protocols. Outline. WAVE Introduction WAVE1609.1 WAVE1609.2 WAVE1609.3 WAVE1609.4 各國發展現況. Introduction. DSRC 泛指所有短距離的無線通訊技術，包含不同的技術和不同的規格，而用於交通上的 5.9GHz DSRC 在 MAC 與 PHY 的底層為 IEEE802.11p.

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車輛定位與電子地圖整合服務 Vehicle Positioning, Digital Maps and Integrated Services

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  1. 車輛定位與電子地圖整合服務Vehicle Positioning, Digital Maps and Integrated Services Lecture 7 WAVE Protocols

  2. Outline WAVE Introduction WAVE1609.1 WAVE1609.2 WAVE1609.3 WAVE1609.4 各國發展現況

  3. Introduction DSRC泛指所有短距離的無線通訊技術，包含不同的技術和不同的規格，而用於交通上的5.9GHz DSRC在MAC與PHY的底層為IEEE802.11p. 802.11p是IEEE在2003年以802.11a為基礎所制定，又稱為WAVE(Wireless Access in the Vehicular Environment)，將會被用在DSRC系統中。 優點為：可用於高速移動、美國運輸部以該標準建置基礎建設。

  4. Introduction ITS概觀，DSRC的重點在於紅色區塊。

  5. Introduction 車內通訊: Bluetooth (BT), Ultra-wideband (UWB) 車外通訊: 2G, 2.5G, 3G, 3.5G (cellular systems), GPS, WiMAX 車路通訊: Microwave, Infrared, Dedicated Short Range Communications (DSRC), Wi-Fi 車間通訊: Microwave, Infrared, DSRC

  6. Introduction • 車路通訊與車間通訊其實是同一技術的兩種不同應用模式，通訊距離大約介於數百公尺至一公里左右的範圍，再依據不同的實體介質可細分為： • 微波(microwave) • 紅外線(infrared) • 無線電(radio frequency, e.g. DSRC) • 主要差異在於介質穿透能力及資料傳輸速率高低，而相對移動速度對於通訊效能的影響也會因介質而異。

  7. Introduction 車路通訊(V2R, OBU-to-RSU／RSU-to-OBU)應用模式下至少有一方是維持不動的，例如自動電子收費、自動取得前方交通路況、停車場資訊、定點影音資訊上傳及下載等。 在車間通訊(V2V, OBU-to-OBU)應用模式時就是屬於多動點之間的雙向傳輸，主要被應用於車輛安全防撞訊息的交換，其安全與即時性的需求均高。

  8. DSRC

  9. 各式無線通訊接取技術

  10. DSRC/WAVE頻譜分佈圖

  11. DSRC/WAVE的標準架構

  12. WAVE Protocol Stack Model OSI Reference Model Application ApplicationPresentationSession Security Services 1609.1 WME UDP/TCP WSMP Transport IPv6 1609.2 Network 1609.3 LLC Data Link 802.2 MLME WAVE MAC 802.11 Multi-channel operation 1609.4 802.11p PLME WAVE Physical Physical 1609.3 Data plane Management plane

  13. Noun interpret(1) • Wireless access in vehicular environment (WAVE): IEEE 所制定用於對車輛與車輛，車輛與路邊裝置的無線通信。 • Onboard unit (OBU):一個可移動的WAVE裝置，可和路邊RSU和其他的OBU裝置進行通訊。 • Roadside unit (RSU):一個固定式的WAVE裝置，可和OBUs裝置交換訊息。

  14. Noun interpret(2) • Provider Service Table (PST):紀錄傳輸的WAVE device和支援channel的資訊。 • Provider Service Context (PSC):一個欄位的組合，包含PSID與一些增補資訊如版本。 • Provider service identifier (PSID)：應用程式提供唯一的編號用來識別該服務。

  15. Noun interpret(3) • WAVE management entity (WME):對WAVE networking服務所提供的管理服務 • WAVE short message (WSM):一種可以不需要透過IP而可以由WAVE device間直接交換訊息資料的資料結構。 • WAVE short message protocol (WSMP): WAVE shot message所使用的通訊協定。

  16. Noun interpret(4) • WAVE basic service set (WBSS)：為一個集合，內含兩個或多個WAVE裝置互相參與在同一個SCH上的通訊。一個WBSS被創建是由一個WAVE裝置使用一個WAVE發佈活動訊框在CCH上。 • WAVE routing advertisement (WRA):RSU的網路配置資訊廣播

  17. Noun interpret(5) • WAVE service advertisement (WSA)：WAVE服務公告由WME配置資料與收集，提供識別WAVE應用程式與用來連結的網路參數。 • WAVE service information element (WSIE)：一個WAVE發佈活動訊框中的欄位，被使用來通知WAVE服務開始被提供。

  18. System components and connectivity • Two types of systems identified in the WAVE standards. The first type is a roadside unit (RSU). The second type is an onboard unit (OBU).

  19. IEEE 1609.1 IEEE 1609.1: resource manager IEEE 1609.1 為 WAVE 的資源管理。這個標準制定一個用於 DSRC 應用與 WAVE 環境中的無線存取方式，允許遠端應用程式與車上裝置 (OBU) 或路邊裝置 (RSU) 之間的通訊，WAVE的資源管理扮演一個應用層的角色，其通訊的目的是引導資訊交換。

  20. IEEE 1609.2 IEEE 1609.2 : secure message formats to process secure messages of the DSRC/WAVE 主要目的在發展與定義安全訊息格式、處理 DSRC 與 WAVE 系統內部中的安全訊息它同時也討論： WAVE管理訊息與應用程式訊息的加密方法 車輛引起的安全訊息例外處理 支援核心安全功能的必要管理功能

  21. Scope & purpose • Define secure message formats, the processing of the secure messages within the DSRC/WAVE system • Method for securing WAVE management messages and application messages excepting vehicle-originating safety messages • Services used to protect messages from attacks

  22. WAVE systems overview • Entities in the system • Providers • Users • RoadSide Units (RSUs) • WAVE devices operate only when stationary • Support information exchange with OBUs • Usually be providers • On-Board Units (OBUs) • WAVE devices operate in motion • Support information exchange with RSUs and other OBUs • Usually be users (may be providers) • Public Safety On-Board Units (PSOBUs) • Certificate Authorities (CAs) • Support security services • Authorize other entities via the issuance and revocation of certificates

  23. WAVE systems overview

  24. WAVE systems overview-Messages for WAVE radio stack • WAVE Short Message (WSM) for broadcast applications over WSMP (network layer) • UDP/IP stack for transactional applications (network layer) • WAVE Service Announcement (WSA) for providers notifies users which the services are and what service channel(s) they are provided on (MAC layer) • All generated by the WAVE Management Entity (WME)

  25. WAVE systems overview –Security services • Applications over UDP use the secured message formats to protect application data (Encrypted Message) • Application over WSMP use the secured message formats or the secured WSM types to protect application data (Signed Message) • WME uses the secured WSIE type to preventing fake services (Signed Message)

  26. Secured message format

  27. Secured message format

  28. Secured message format

  29. Secured message format

  30. Secured message format

  31. Secured message format

  32. Secured message format

  33. Secured message examples

  34. Secured message examples

  35. Communication security overview • Attacks • Intercept a message • Alter the message • Replay a message • Prevention • Confidentiality – encrypting the message • Authenticity – confirmation of origin of the message • Integrity – confirmation that the message has not been altered

  36. Cryptographicservices • Symmetric algorithm (secret-key) • Two entities share a secret-key and uses this key to encrypt/decrypt the message and provide authenticity and integrity • Only the party shares the key knows who generates the message • AES-CCM (authenticate-then-encrypt) adopted by this standard • Asymmetric algorithm (public-key) • Two keys: public key and private key • In WAVE context, broadcast messages are signed and are not be encrypted • Transactional messages are protected with asymmetric or symmetric algorithms

  37. Cryptographic services • Hash functions • SHA-1 are adopted by this standard • Use to generate identifiers to certificates and fragmented messaged • For efficiently operate the cryptographic algorithm • Asymmetric algorithms are used to setup a secure-session • Symmetric algorithms are then used to protect data

  38. The construction and use of signed messages

  39. Flow Chart

  40. Summary of IEEE 1609.2

  41. Anonymity • Mechanism for providing anonymous authenticated broadcast messaged are not given in this standard at this time • The current standard is focus on protecting message payloads and does not provide the protection for message headers

  42. IEEE 1609.3 IEEE 1609.3 : network services 提供 WAVE 網路服務給 WAVE 裝置與系統，它定義操作在網路層與傳輸層的 WAVE 網路服務，粗略的重新展現 OSI 網路模型的第三、四層。 IEEE 1609.3 的網路服務提供兩大類的傳輸服務：IPv6 傳輸服務、WAVE short message (WSM)短訊服務

  43. WAVE network services (1/3) IEEE 1609.3 的制定目的在於提供WAVE系統的定址及路由的服務。 IEEE 1609.3 規範了在 5.9GHz 的 DSRC/WAVE 模式下，無線連接車用裝置和車用裝置與固定的路邊裝置的網路層及傳輸層的服務及操作。

  44. WAVE network services (2/3) 定義 WAVE 的網路服務，我們可以從資料面及管理面來討論。 Data Plane(資料面) 定義使用現有的 UDP (TCP選用)、IPv6 與邏輯鏈結控制，車用無線存取環境的短訊息 WAVE Short Message (WSM) 與其通訊協定Protocol (WSMP) 。 控制發射功率、資料傳輸速率及廣播頻道。 WAVE的執行應至少支持一種IPv6或WSMP的傳輸

  45. WAVE network services (3/3) Management Plane(管理面) 應用程式的登錄。 管理車用無線存取環境基礎服務(WAVE basic service set ,WBSS)。 頻道使用狀態監控。 IPv6 的配置。 接收頻道能量監控。

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