1 Dedicated Short Range Communication DSRC 2020125 2

1 (Dedicated Short Range Communication, DSRC)專用短距離 通訊 指導老師：童曉儒 教授 報告人：張益瑞 2020/12/5

2 2020/12/5 Outline • • Introduction WAVE 1609. 3 WAVE 1609. 4 各國發展現況

4 2020/12/5 Introduction • ITS概觀，DSRC 的重點在於紅色 區塊。

5 2020/12/5 Introduction • 車內通訊: Bluetooth (BT), Ultra-wideband (UWB) • 車外通訊: 2 G, 2. 5 G, 3. 5 G (cellular systems), GPS, Wi. MAX • 車路通訊: Microwave, Infrared, Dedicated Short Range Communications (DSRC), Wi-Fi • 車間通訊: Microwave, Infrared, DSRC

6 2020/12/5 Introduction

14 2020/12/5 DSRC/WAVE的標準架構

15 2020/12/5 DSRC/WAVE頻譜分佈圖

16 2020/12/5 IEEE 1609 -Sponsor • The Intelligent Transportation Systems （ITS） Committee of the IEEE Vehicular Technology Society（ VTS ） • DOT ITS Program ▫ Department of Transportation（ DOT ） • Major Objective on ITS ▫ Intelligent Infrastructure, IF ▫ Intelligent Vehicles, IV

2020/12/5 17 IEEE 1609 WAVE Network V to R Roadside Unit （ RSU ） V to V Onboard Unit （ OBU ） Source: http: //3 fire. blogspot. com/2007/06/wave-ieee-1609. html

2020/12/5 18 WAVE Protocol Stack Model Application 1609. 1 WME Security Services UDP/TCP WSMP IPv 6 1609. 3 802. 2 1609. 2 OSI Reference Model Application Presentation Session Transport Network LLC Data Link MLME 1609. 3 PLME Management plane 802. 11 WAVE MAC 802. 11 p 1609. 4 Multi-channel operation WAVE Physical Data plane Physical

2020/12/5 22 IEEE 1069. 3 Protocol Stack Model Application WME UDP/TCP WSMP non-IP based IPv 6 Focus of enhancements Specified by this standard LLC MLME PLME Management plane WAVE MAC Multi-channel operation WAVE Physical Data plane

2020/12/5 26 Communication protocols (1/2) • Channel types ▫ CCH (single control channel) 保留給short、high-priority application 及 system control message使用。 ▫ SCH (multiple service channel) 支援一般目的的應用資料傳輸。

2020/12/5 28 WAVE Service Information Element (WSIE) Reference by IEEE 1609. 3

2020/12/5 30 Reference Model Application WME UDP/TCP WSMP IPv 6 LLC MLME WAVE MAC with channel coordination PLME WAVE Physical Management plane Data plane Focus of enhancements Specified by this standard

2020/12/5 31 General Description • WAVE devices (OBU or RSU) provide an architecture that supports a single CCH and multiple SCHs. • CCH ▫ 用來傳輸WSM及發佈WAVE服務。 • SCHs ▫ 用來讓應用程式的互動或傳輸訊息用。

2020/12/5 32 Provide Functions • Channel routing ▫ Routing for WSMP data ▫ Routing for IP datagram • User priority (UP) • Channel coordination

2020/12/5 33 Routing for WSMP data (1/2) 1 octet channel power data rate WSMP header Source: IEEE 1609. 4 • WSMP header contains the channel, power level, and data rate

2020/12/5 34 Routing for WSMP data (2/2) • Routing Script Scenario ▫ 首先 WSMP data 從 LLC 層被傳送到 MAC 層。 ▫ 接下來 MAC 會路由該封包到適當的 buffer 也就是 在 WSMP header 中所指的channel number。 ▫ 如果 WSMP header 中所指的 channel number 是無效 的，則該封包會被摒棄，而所謂無效的 channel number 是指它並非對應到 CCH number 或目前的 SCH number。

2020/12/5 36 Routing for IP diagrams (2/2) • Data shall be discarded： ▫ 一是該封包在傳輸之前並沒做任何註冊的動作 ▫ 一是該傳輸的 WAVE 裝置並非是一個 WBSS (WAVE basic service set) 的成員。

2020/12/5 37 User priority (1/2) • IEEE 1609 使用 IEEE 802. 11 e 的增強分散頻道存 取 (Enhanced Distributed Channel Access mechanism ，EDCA) 的機制，來用於競爭媒體的 存取。媒體存取控制根據存取分類索引與使用者 優先權的配對決定將資料置於何佇列。EDCA 相 關的參數如下： ▫ Arbitration inter-frame space (AIFS) ▫ Contention window (CW) ▫ Transmit opportunity (TXOP) limit

2020/12/5 38 User priority (2/2) MAC ACI = 1 ACI = 2 ACI = 3 AIFS[ACI] CW[ACI] TXOP[ACI] ACI = 0 Transmit Queues Pre-queue channel access functions AIFS[ACI] CW[ACI] TXOP[ACI] • 圖中展示了在一個 Channel 的情況下，資料 封包於(MAC層)競爭的 概念圖。 LLC Internal Contention Medium Contention PHY Source : IEEE 1609. 4

2020/12/5 39 Channel coordination Sync Interval CCH Interval Source: IEEE 1609. 4 Guard Interval

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