doc.: IEEE 802.11-14/0259r0
Submission
February 2014
Malik Kahn (Cohda Wireless)Slide 1
IEEE 802.11 Regulatory SCDSRC Coexistence Tiger Team
V2V Radio Channel Models
Date: 2014-02-21
Name Affiliations Address Phone email Malik Kahn Cohda Wireless 82-84 Melbourne St,
North Adelaide, SA 5006 Australia
+61 8 8361 7297 [email protected]
Authors:
doc.: IEEE 802.11-14/0259r0
Submission Malik Kahn (Cohda Wireless)
AbstractChannel models for vehicle to vehicle communications in
the 5.6-5.9GHz band.
February 2014
Slide 2
doc.: IEEE 802.11-14/0259r0
Submission
Background Work: References• Ian Tan, Wanbin Tang, Ken Laberteaux, Ahmad Bahai ,
“Measurement and Analysis of Wireless Channel Impairments in DSRC Vehicular Communications,” Electrical Engineering and Computer Sciences University of California at Berkeley, April 2008.
• Paul Alexander, David Haley, Alex Grant , “Cooperative Intelligent Transport Systems: 5.9-GHz Field Trials,” Proceedings of The IEEE Volume:99 , Issue 7, July 2011
• Laura Bernado, Thomas Zemen, Fredrik Tufvesson, Andreas F. Molisch, Christoph F. Mecklenbrauker , “Delay and Doppler Spreads of Non-Stationary Vehicular Channels for Safety Relevant Scenarios,” May 2013
3 Malik Kahn (Cohda Wireless)Slide 3
doc.: IEEE 802.11-14/0259r0
Submission
Merge methodology
• All studies were scenario based and at 5.6 to 5.9 GHz. Not all scenarios were in common.
• The antenna systems and transmitted power were different across tests
• All studies reported RMS Doppler and Delay Spread.
• Created a table with Scenario and RMS Delay and Doppler spread, then determined multipath Taps that deliver those statistics
Malik Kahn (Cohda Wireless)Slide 4
doc.: IEEE 802.11-14/0259r0
Submission
Scenario Descriptions
5
Rural LOS:Intended primarily as a reference result, this channel applies in very open environments where other vehicles, buildings and large fences are absent.
Urban Approaching LOS:Two vehicles approaching each other in an Urban setting with buildings nearby.
Malik Kahn (Cohda Wireless)Slide 5
doc.: IEEE 802.11-14/0259r0
Submission
Scenario Descriptions
6
Street Crossing NLOS:Two vehicles approaching an Urban blind intersection with other traffic present. Buildings/fences present on all corners.
Highway LOS:Two cars following each other on Multilane inter-region roadways such as Autobahns. Signs, overpasses, hill-sides and other traffic present.
Highway NLOS:As for Highway LOS but with occluding trucks present between the vehicles.
Malik Kahn (Cohda Wireless)Slide 6
doc.: IEEE 802.11-14/0259r0
Submission
Channel Model Scenarios
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RMS Delay Spread (ns) Berkeley Cohda Lund Merged
Rural LOS 22 49 30
Urban Approaching LOS 320 81 84 100
Street Crossing NLOS 295 125 58 200
Highway LOS 140 62 120
Highway NLOS 398 131 36 250
Doppler Spread (Hz) Berkeley Cohda Lund Merged (RMS)
Rural LOS 782 188 100
Urban Approaching LOS 263 353 297 150
Street Crossing NLOS 298 360 420 180
Highway LOS 895 826 380
Highway NLOS 978 875 236 420
Name Berkeley Cohda LundRuralLOS RuralLOS na Merging Lanes RuralUrbanApproachingLOS
UrbanLOS UrbanLOS street crossing - suburban without traffic
CrossingNLOS UrbanNLOS UrbanNLOS street crossing -urban single laneHighwayLOS HighwayLOS HighwayLOS naHighwayNLOS HighwayNLO
SHighwayNLOS general LOS obstruction - highway
Malik Kahn (Cohda Wireless)Slide 7
doc.: IEEE 802.11-14/0259r0
Submission
Doppler Spectra• The Delay and Mean Power of the taps is a strong function of the environment
whereas the Doppler frequencies can scale with speed stipulated as part of the scenario.
• We want asymmetric spectra, and thus the Doppler spectra is specified as half-bath tub. Other options are a uniform offset Classic Bathtub.
• The key attributes of these Doppler spectra are that they induce a significant bias to the instantaneous Doppler consistent with the constant macro dynamics of the scenario.
• For example two cars approaching a blind intersection will tend to compress frequency on the direct path but may stretch frequency on a reflected path of a following truck.
8
fd-fd 0Doppler freq
PureDoppler
Classic Bath TubPower
Asymmetric Uniform
Malik Kahn (Cohda Wireless)Slide 8
doc.: IEEE 802.11-14/0259r0
Submission
Channel Model Values
Tap1 Tap2 Tap3 Units
Power 0 -14 -17 dBDelay 0 83 183 ns
Doppler 0 492 -295 HzProfile Static HalfBT HalfBT
Table 5: Rural LOS Parameters
Tap1 Tap2 Tap3 Tap4 Units
Power 0 -8 -10 -15 dBDelay 0 117 183 333 ns
Doppler 0 236 -157 492 HzProfile Static HalfBT HalfBT HalfBT
Table 6: Urban Approaching LOS Parameters
Tap1 Tap2 Tap3 Tap4 Units
Power 0 -3 -5 -10dBDelay 0 267 400 533ns
Doppler 0 295 -98 591HzProfile Static HalfBT HalfBT HalfBT
Table 7: Crossing NLOS Parameters
Tap1 Tap2 Tap3 Tap4 Units
Power 0 -10 -15 -20dBDelay 0 100 167 500ns
Doppler 0 689 -492 886HzProfile Static HalfBT HalfBT HalfBT
Table 8: Highway LOS Parameters
Tap1 Tap2 Tap3 Tap4 Units
Power 0 -2 -5 -7dBDelay 0 200 433 700ns
Doppler 0 689 -492 886HzProfile Static HalfBT HalfBT HalfBT
Table 9: Highway NLOS Parameters
252 km/hr max differential
252 km/hr max differential119km/hr max differential
126km/hr max differential
144km/hr max differential
Malik Kahn (Cohda Wireless)Slide 9
doc.: IEEE 802.11-14/0259r0
Submission
Channel Model Values• For each of the five scenarios modelled, we show the
relevance of these delays and Doppler's in terms of path length difference (in meters) and relative path speed (in m/s.
• Last column shows the maximum speed difference between the taps.
Slide 10
Name RMS Spread Tap 2 Tap 3 Tap 4 Unit
Doppler Spread km/hr
Rural LOS 29.2 25 55 m102.8 25 -15 m/s 144
Urban LOS 49.4 35 55 100 m58.2 12 -8 25 m/s 119
Urban NLOS 287.7 80 120 160 m167.2 15 -5 30 m/s 126
Highway LOS 31.6 30 50 150 m154.5 35 -25 45 m/s 252
Highway NLOS 371.0 60 130 210 m439.4 35 -25 45 m/s 252
Malik Kahn (Cohda Wireless)
doc.: IEEE 802.11-14/0259r0
Submission
Further Comments & QAs
• The specified Doppler spectrum is Half bath tub. The Doppler of each tap changes with time and visits the extreme value (listed in the tables) with highest likelihood. It follows that the worst case instantaneous Doppler scenario could be obtained by using pure Doppler taps.
• Another point to note is that because these channel models were derived from the RMS Delay and Doppler spread there is no residual group Doppler or Delay remaining in the channel models. We do not view this as a problem from the device testing point of view. As both group delay and Doppler (frequency) are removed by receivers.
11 Malik Kahn (Cohda Wireless)Slide 11