IEEE 802.11 Regulatory SC DSRC Coexistence Tiger Team V2V Radio Channel Models

1. IEEE 802.11 Regulatory SCDSRC Coexistence Tiger TeamV2V Radio Channel Models Date: 2014-02-21 Authors: Malik Kahn (Cohda Wireless)

2. Abstract Channel models for vehicle to vehicle communications in the 5.6-5.9GHz band. Malik Kahn (Cohda Wireless)

3. 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 Slide 3 Malik Kahn (Cohda Wireless)

4. 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)

5. Scenario Descriptions Malik Kahn (Cohda Wireless) Slide 5

6. Scenario Descriptions Malik Kahn (Cohda Wireless) Slide 6

7. Channel Model Scenarios Malik Kahn (Cohda Wireless) Slide 7

8. 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. Classic Bath Tub Power Asymmetric Uniform PureDoppler Doppler freq -fd 0 fd Malik Kahn (Cohda Wireless) Slide 8

9. Channel Model Values 144km/hr max differential 252 km/hr max differential Table 5: Rural LOS Parameters Table 8: Highway LOS Parameters Table 6: Urban Approaching LOS Parameters 252 km/hr max differential Table 9: Highway NLOS Parameters 119km/hr max differential Table 7: Crossing NLOS Parameters 126km/hr max differential Malik Kahn (Cohda Wireless)

10. 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. Malik Kahn (Cohda Wireless)

11. 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. Malik Kahn (Cohda Wireless) Slide 11