1 / 17

IEEE 802.11p Draft Review

IEEE 802.11p Draft Review. Wayne Fisher Broady Cash ARINC, Inc Annapolis, MD. DSRC and WAVE Terminology. DSRC – Dedicated Short-range Communications is the name of the 5.9 GHz Band allocated for the ITS communications

stacey
Download Presentation

IEEE 802.11p Draft Review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IEEE 802.11p Draft Review Wayne Fisher Broady Cash ARINC, Inc Annapolis, MD WKFisher/ARINC

  2. DSRC and WAVE Terminology • DSRC – Dedicated Short-range Communications is the name of the 5.9 GHz Band allocated for the ITS communications • WAVE – Wireless Access in Vehicular Communications is the mode of operation used by IEEE 802.11 devices to operate in the DSRC band WKFisher/ARINC

  3. DSRC Devices • DSRC Devices are IEEE 802.11 systems using the WAVE mode of operation in the DSRC band WKFisher/ARINC

  4. Implementing WAVE Mode • 5.1.2.6 WAVE Mode • The WAVE mode is used to allow IEEE 802.11 units in the DSRC band to both broadcast messages and establish almost instantaneous links for data transfer with fast moving vehicles • The WAVE mode provides two basic types of communication services: • Broadcast – Listener • Provider – User WKFisher/ARINC

  5. Implementing WAVE Mode, 2 • Settings on power-up to operate in the WAVE Mode • a. Channel scan shall be disabled. • b. The channel shall be set to 178. • c. The data rate shall be set to 6 Mbps. • d. The unit shall be able to receive at any mandatory data rate. WKFisher/ARINC

  6. Implementing WAVE Mode, 3 • Roadside Units (RSUs) meet the FCC Safety Message priority requirement by broadcasting Safety messages in Message Elements in Beacon or Action Frames primarily on the Control Channel • Onboard Units (OBUs) meet the FCC Safety Message priority requirement by broadcasting Safety messages in Message Elements in Action Frames primarily on the Control Channel WKFisher/ARINC

  7. Implementing WAVE Mode, 4 • Non-Safety Messages are sent in Message Elements in Action Frames • For RSUs the message duration is limited to 750 us and a minimum interval of 100 ms. For OBUs the message duration shall be limited to 580 us at a minimum interval of 750 ms WKFisher/ARINC

  8. Implementing WAVE Mode, 5 • Roadside Units initiate a link by sending a Provider Service Table (PST) in Beacon Frames on the Control Channel • Onboard Units initiate a link by sending a PST in Action Frames on the Control Channel WKFisher/ARINC

  9. Implementing WAVE Mode, 6 • In establishing the link for data transfer the operating channel is switched from the Control Channel to a Service Channel • Continued WAVE Mode operation may be implemented on this Service Channel or routine BSS or IBSS operations may be implemented WKFisher/ARINC

  10. WAVE Mode Performance Requirements • 5.1.2.2 WAVE Communications • DSRC devices operating in the WAVE Mode are capable of transferring messages to and from vehicles each traveling at speeds up to 140 km/h with a Packet Error Rate (PER) of less than 10% for PSDU lengths of 1000 bytes and to and from vehicles at speeds up to a minimum of 200 km/h with a PER of less than 10 % for PSDU lengths of 64 bytes. For vehicle-to-vehicle communications DSRC devices are capable of transferring messages at closing speeds of up to a minimum of 283 km/h with a PER of less than 10 % for PSDU lengths of 64 bytes. WKFisher/ARINC

  11. Multiple DSRC Devices Single device One device operating on one channel at a time or 5.1.2.10 Multiple Devices Multiple devices each implementing a separate function or application on a different frequency • Multi-device configurations have the advantage of being able to listen for safety messages on the Control Channel and simultaneously conduct an application transaction on one of the two Service Channels at the edge of the DSRC band or in the U-NII band. WKFisher/ARINC

  12. RSSI for WAVE • 17.2.3.2 RXVECTOR RSSI • For the WAVE mode, subsequent to a period of no less than 2 ms after an alert signal, the minimum RSSI resolution should be less than or equal to 0.2 dB and shall be accurate to ± 1 dB across the entire operating temperature range within -60 to -30 dBm of the receiving signal range WKFisher/ARINC

  13. WAVE Spectrum Mask • Offset (MHz) • Class ± 4.5 ± 5.0 ± 5.5 ± 10 ± 15 • Reduction in Power Spectral Density, dBr • Class A 0 -10 -20 -28 -40 • Class B 0 -16 -20 -28 -40 • Class C 0 -26 -32 -40 -50 • Class D 0 -35 -45 -55 -65 WKFisher/ARINC

  14. Back-up Info: WKFisher/ARINC

  15. IEEE 802.11e Reference • 7.1.2 General frame format • Insert the following text at the end of subclause 7.1.2: • For WAVE implementation the QoS Control field shall be used as defined in IEEE 802.11e, Clause 7.1.3.5. WKFisher/ARINC

  16. Correlate with 802.11j • WAVE Channel Implementation • Seven 10 MHz channels • Data Rates for WAVE (Mbits/s) • 3, 4.5, 6, 9, 12, 18, 24, 27 • Modulations • BPSK OFDM, QPSK OFDM, • 16-QAM OFDM, 64-QAM OFDM WKFisher/ARINC

  17. Correlate with 802.11j, 2 • OFDM PHY characteristics • Characteristics 802.11a Value WAVE Values • aSlotTime 9 s 16 s • aSIFSTime 16 s 32 s • aCCATime < 4 s < 8 s • aCHSwitchTime N/A < 2 ms • aAirPropagationTime << 1 s < 4 s • aMACProcessing Delay< 2 s < 2 s • aPreambleLength 20 s 40 s • aPLCPHeaderLength 4 s 8 s WKFisher/ARINC

More Related