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 malik.khan@cohdawireless.com

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