1. doc.: IEEE 802.11-14/1335r1 Submission October 2014 Jim Arnold, US DoTSlide 1 IEEE 802.11 Regulatory SC DSRC Coexistence Tiger Team DSRC Band Plan Rationale Date: 2014-10-03 Authors:

2. doc.: IEEE 802.11-14/1335r1 SubmissionJim Arnold, US DoT Abstract This presentation is a summary of issues in the DSRC band plan October 2014 Slide 2

3. doc.: IEEE 802.11-14/1335r1 Submission Background Material from a report prepared March 14, 2006, by TechnoCom (now part of Kapsch) for ARINC (now Rockwell Collins ARINC). Is available as part of history of DSRC standards development. Formed foundation for several decisions by IEEE DSRC standards Task Group Jim Arnold, US DoT October 2014 Slide 3

4. doc.: IEEE 802.11-14/1335r1 Submission DSRC Band Overview Control Channel (178) used for short messages and directing OBEs to appropriate Service Channels 10 MHz channels (6 Mbps data rate) Option for 20 MHz channels (combining CH 174+176, and 180+182) Jim Arnold, US DoT October 2014 Slide 4

5. doc.: IEEE 802.11-14/1335r1 Submission DSRC Band Plan Overview These were first adopted by ASTM(1) and then the FCC in 2003(2) Jim Arnold, US DoT October 2014 Slide 5

6. doc.: IEEE 802.11-14/1335r1 Submission Receiver Performance Minimum DSRC receiver sensitivity defined in 802.11 standard(3) Doubling channel bandwidth (10 to 20 MHz) also doubles receiver noise power –Receiver noise floor raised by 3 dB Jim Arnold, US DoT October 2014 Slide 6

7. doc.: IEEE 802.11-14/1335r1 Submission Receiver Performance With the same received signal power, a DSRC receiver with a 10 MHz channel has better performance than the one with a 20 MHz channel. To have the same signal coverage as a DSRC radio with a 10 MHz channel, a DSRC radio with a 20 MHz channel needs to double transmission power in free space propagation, even more in multipath fading. Channel bandwidth of a DSRC receiver Guard interval in the OFDM scheme Maximum allowed delay spread 20 MHz 800 ns 10 MHz 1600 ns Jim Arnold, US DoT October 2014 Slide 7

8. doc.: IEEE 802.11-14/1335r1 Submission Channel Capacity Control Channel With the same transmission power in free space propagation, a DSRC radio with a 20 MHz channel has 50% less signal coverage than the one with a 10 MHz channel. Combining the impacts of the raised noise floor and multipath fading, a DSRC radio with a 20 MHz channel needs to more than double the transmission power in order to have the same signal coverage as a DSRC radio with a 10 MHz channel. The higher signal power a transmitter is required to generate, the stronger interference it generates to nearby co- channel transmitters. As a result, the channel capacity is reduced. Service Channels The control channel capacity with a high message receipt rate (95%) for a 10 MHz channel can meet the requirements of most traffic situations. Using a 20 MHz channel does not help. Jim Arnold, US DoT October 2014 Slide 8

9. doc.: IEEE 802.11-14/1335r1 Submission Channel Re-Use Frequency reuse with four10 MHz service channels 1 st 10 MHz SCH 2 nd 10 MHz SCH 3rd 10 MHz SCH 4th 10 MHz SCH Jim Arnold, US DoT October 2014 Slide 9

10. doc.: IEEE 802.11-14/1335r1 Submission Channel Re-Use Frequency reuse with two 20 MHz service channels Jim Arnold, US DoT October 2014 Slide 10

11. doc.: IEEE 802.11-14/1335r1 Submission Summary Doubling channel bandwidth requires doubling transmit power for same coverage o Even more in multipath fading o Channel capacity reduced due to co-channel interference 10 MHz Service Channels = more Service Channels available in an area o 10 MHz channels at least 50% more efficient than 20 MHz channels Using 20 MHz Control Channel does not aid message success rate Existing DSRC channel plan is optimized for balancing performance and capacity Jim Arnold, US DoT October 2014 Slide 11

12. doc.: IEEE 802.11-14/1335r1 Submission Footnotes and other reference material 1. ASTM E2213 (2003): 5.9GHz DSRC PHY and MAC Specification. 2. FCC CFR47 Part 90, Subparts I and M. 3. IEEE Std. 802.11-2005 (REVma/D4.0), Information technology— Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications. Additional reference material: http://www.standards.its.dot.gov/Factsheets/Factsheet/66 https://mentor.ieee.org/802.11/documents?is_dcn=DCN%2C%20Title%2C %20Author%20or%20Affiliation&is_group=0reghttps://mentor.ieee.org/802.11/documents?is_dcn=DCN%2C%20Title%2C %20Author%20or%20Affiliation&is_group=0reg Look under DSRC SG, TGp, and WAVE SG Lin Cheng ; Carnegie Mellon Univ., Pittsburgh, PA, USA ; Henty, B.E. ; Cooper, R. ; Stancil, D.D., A Measruement Study of Time-Scaled 802.11 waveforms over the Mobile-to-Mobile Vehicular Channel at 5.9 GHz, IEEE Communications Magazine, Volume 48, Issue 5Lin ChengHenty, B.E. Cooper, R.Stancil, D.D.A Measruement Study of Time-Scaled 802.11 waveforms over the Mobile-to-Mobile Vehicular Channel at 5.9 GHz Jim Arnold, US DoT October 2014 Slide 12