V2x wireless channel modeling for connected cars. Taimoor Abbas Volvo Car Corporations

Transcription

1 V2x wireless channel modeling for connected cars Taimoor Abbas Volvo Car Corporations

2 V2X Terminology Background V2N P2N V2P V2V P2I V2I I2N 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 2

3 Wireless channel Background Transmit antenna Propagation channel Receiver antenna Radio channel The wireless channel is a medium used to transmit data wirelessly from the transmitter to the receiver antenna. 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 3

4 Wireless channel Background Why do we need wireless channel modeling? Ideally, modeling a channel means to calculate or estimate all the processing, due to the physical environment, effecting a signal from the transmitter to the receiver. How wireless channel is modeled? Wireless channel is modeled analytically with the help of simulations or empirically by real world measurements. Where it is used? For the wireless system design, it is used for link-level or system simulations as well as to test the hardware especially where control and repeatability is required. It can also be used to bench mark multiple hardware with standard settings. The major benefits are? Easy to use, allow better control and repeatability, cost effective and could be scaled 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 4

5 Propagation mechanism Typical communication scenario i r Background 1 2 t Reflection and transmission Diffraction Line-of-sight (LOS) component Multipath components Scattering Waveguiding 5

6 Propagation mechanism (cont.) If we assume the TX/RX antennas to be isotropic being in free space, Background Path loss d A RX P RX = 4 d 2 P TX L free ( d ) = 2 4 d Large scale fading Small scale fading 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 6

7 V2V vs v2i V2X Channel 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 7

8 Doppler shift for v2v 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 8

9 Key Differences in V2V Channel Modeling LOS: Line-Of-Sight OLOS: Obstructed Line-Of-Sight V2X Channel NLOS: Non Line-Of-Sight Multilink g 2, XC90 g 2, Truck g 1 d r, XC90 W r d r, Truck XC90 Black Truck Blue d t g 2, XC90 W t S60 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 9

10 V2X Channel Measurements Modeling 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 10

11 Channel Sounder Modeling 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 11

12 Measurement based modeling Note: Measurement tool always has certain limitations It is necessary to keep those limitations in mind when establishing models based on the measurements For a channel model to be independent of object, it has to be double directional and antennas need to be calibrated so that the response could be subtracted later on 6/12/2018SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 12

13 Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measurements 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 13

14 Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measurements 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 14

15 Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measurements 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 15

16 Power General observations v2v measurements Time-delay characteristics: Houses, road signs etc. RX Discrete comp. LOS t = s s Diffuse comp. TX Other vehicles Rapidly varying channel Propagation distance [m] Discrete components carry significant energy and change delay bin with time Diffuse components following LOS 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 16

17 General observations v2v measurements Local scattering function: Discrete components -50 LOS Power [db] Diffuse components can change delay bin rapidly Discrete components: small Doppler but spread, Delay [ns] Doppler frequency [Hz] Diffuse components: large delay and Doppler spread Time-variant Doppler spectrum Non-stationary conditions 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 17

18 Measurement based modeling Highway, opposite direction Highway, same direction Urban, same direction 23 ms 1479 ms 1412 ms The time during which the local scattering function is sufficiently constant is defined as the stationarity time 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 18

19 A geometry based stochastic model Mobile discrete scatterers Diffuse scatterers Dependent on antenna pattern Static discrete scatterers Adding up all components using different antenna patterns MIMO channels 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 19

20 Deterministic modeling Non-measurement based modeling could either be statistical geometry based of deterministic Deterministic approach, such as ray tracing, can be very realistic but computationally expensive Moreover, it requires accurate geometry Solve approximation to Maxwell s equation, using high-frequency approximation [Maurer et al. 2004] 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 20

21 Ray tracing example 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 21

22 Measurements vs ray tracing Measuremed PDP Simulated PDP (Ray-tracing) Channel gain Very good agreement in LOS and near LOS regions. NLOS LOS In NLOS, the ray tracing model underestimates the channel gain. Gap can be reduced by increasing the order of reflection. Contribution of third and higher-order specular and nonspecular reflections is missing in the simulator. 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 22

23 Channel models for test and simulations A channel model is selected based on what part of the communication system that is going to be studied. For network level simulations, where communication protocols are studied, a statistical model (e.g., Rician, Rayleigh, and Nakagami) is the predominant channel model type to keep computational time down. For PHY layer, TDLs and geometry-based stochastic and deterministic channel models are for obvious reasons the preferred channel models. So selection of channel model has to be made very carefully as the channel is one of the major performance factors To summarize; following is a receipe on the selection and usage of channel models. 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 23

24 V2X- Channel: Specific considerations V2X Channel 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 24

25 V2x channel models classification 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 25

26 3GPP TR38.901: V2X-specific Considerations 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 26

27 3GPP TR38.901: V2X-specific Considerations 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 27

28 3GPP TR38.901: V2X-specific Considerations 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 28

29 3GPP TR38.901: V2X-specific Considerations 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 29

30 3GPP TR38.901: V2X-specific Considerations 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 30

31 Summary of parameter to be used 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 31

32 References 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 32

33 acknowledgement I would like to thank my colleagues from Lund University as some of the work is produced jointly, especially Fredrik Tufvesson, Johan Kåredal and Mikael Nilsson. Special thanks to Mate Boban from Huawei, Munich, for sharing information about the activities at 3GPP and for the cooperation under the umbrella of 5GCAR on channel modeling. Thank you for listening! 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 33

34 Selected publications A. Paier, J. Kåredal, N. Czink, C. Dumard, T. Zemen, F. Tufvesson, A. Molisch, C. F. Mecklenbräuker, Characterization of Vehicle-to-Vehicle Radio Channels from Measurements at 5.2GHz, Wireless Personal Communications, vol. 50, no. 1, pp , J. Kåredal, F. Tufvesson, N. Czink, A. Paier, C. Dumard, T. Zemen, C. Mecklenbräuker, A. Molisch, A geometry-based stochastic MIMO model for vehicle-to-vehicle communications, IEEE Transactions on Wireless Communications, vol. 8, no. 7, pp , A. Molisch, F. Tufvesson, J. Kåredal, C. F. Mecklenbräuker, A Survey on Vehicle-to-Vehicle Propagation Channels, IEEE Wireless Communications, vol. 16, no. 6, pp , J. Kåredal, F. Tufvesson, T. Abbas, O. Klemp, A. Paier, L. Bernadó, A. Molisch, Radio channel measurements at street intersections for vehicle-to-vehicle applications, Proc. IEEE Vehicular Technology Conference (VTC2010-spring), Taipei, Taiwan, pp. 1-5, May 16-19, A. Paier, L. Bernadó, J. Kåredal, O. Klemp, A. Kwoczek, Overview of vehicle-to-vehicle radio channel measurements for collision avoidance applications, Proc. IEEE Vehicular Technology Conference (VTC2010-spring), Taipei, Taiwan, pp. 1-5, May 16-19, A. Molisch, F. Tufvesson, J. Kåredal, C. Mecklenbräuker, Propagation aspects of vehicle-to-vehicle communications - an overview, Proc. IEEE Radio and Wirless Symposium (RWS), San Diego, CA, USA, pp , Jan , J. Kåredal, F. Tufvesson, N. Czink, A. Paier, C. Dumard, T. Zemen, C. Mecklenbräuker, A. Molisch, Measurement-based modeling of vehicle-to-vehicle MIMO channels, Proc. IEEE International Conference on Communications (ICC), Dresden, Germany, June 14-18, /12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 34

35 Selected publications A. Paier, T. Zemen, J. Kåredal, N. Czink, C. Dumard, F. Tufvesson, C. Mecklenbräuker, A. Molisch, Spatial diversity and spatial correlation evaluation of measured vehicle-to-vehicle radio channels at 5.2 GHz, Proc. IEEE Digital Signal Processing Workshop/Signal Processing Education Workshop (DSP/SPE), pp , Jan 1-4, L. Bernadó, T. Zemen, A. Paier, J. Kåredal, B. Fleury, Parametrization of the local scattering function estimator for vehicular-to-vehicular channels, Proc. IEEE Vehicular Technology Conference (VTC2009-fall), Anchorage, AK, USA, pp. 1-5, Sept , A. Paier, T. Zemen, L. Bernado, G. Matz, J. Kåredal, N. Czink, C. Dumard, F. Tufvesson, A. Molisch, C. Mecklenbräuker, Non-WSSUS vehicular channel characterization in highway and urban scenarios at 5.2 GHz using the local scattering function, Proc. International Workshop on Smart Antennas (WSA), pp. 9-15, L. Bernadó, T. Zemen, A. Paier, G. Matz, J. Kåredal, N. Czink, C. Dumard, F. Tufvesson, M. Hagenauer, A. Molisch, C. F. Mecklenbräuker, Non-WSSUS Vehicular Channel Characterization at 5.2 GHz - Spectral Divergence and Time-Variant Coherence Parameters, Proc. URSI General Assembly, A. Paier, J. Kåredal, N. Czink, H. Hofstetter, C. Dumard, T. Zemen, F. Tufvesson, C. Mecklenbräuker, A. Molisch, First results from car-to-car and car-to-infrastructure radio channel measurements at 5.2GHz, Proc. IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Athens, Greece, pp. 1-5, Sept. 3-7, A. Paier, J. Kåredal, N. Czink, H. Hofstetter, C. Dumard, T. Zemen, F. Tufvesson, A. Molisch, C. Mecklenbräuker, Car-tocar radio channel measurements at 5 GHz: Pathloss, power-delay profile, and delay-doppler spectrum, Proc. IEEE International Symposium on Wireless Communication Systems (ISWCS), Trondheim, Norway, pp , Oct , /12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 35

36 Selected publications C. Mecklenbräuker, A. Molisch, J. Karedal, F. Tufvesson, A. Paier, L. Bernadó, T. Zemen, O. Klemp, N. Czink: Vehicular channel characterization and its implications for wireless system design and performance, Proceedings of the IEEE, Vol. 99, No. 7, pp , T. Abbas, J. Karedal, F. Tufvesson, A. Paier, L. Bernadó, A. Molisch: Directional Analysis of Vehicle-to-Vehicle Propagation Channels, IEEE Vehicular Technology Conference, IEEE 73rd Vehicular Technology Conference 2011-spring, Budapest, Hungary, / T. Abbas, and F. Tufvesson: Line-of-Sight Obstruction Analysis for Vehicle-to-Vehicle Network Simulations in a Two Lane Highway Scenario, Hindawi International Journal of Antennas and Propagation, Special Issue on Radio Wave Propagation and Wireless Channel Modeling (In press) T. Abbas, L. Bernadó, A. Thiel, C. F. Mecklenbräuker, and F. Tufvesson: Radio Channel Properties for Vehicular Communication: Merging Lanes Versus Urban Intersections, IEEE Vehicular Technology Magazine, December, 2013 (Invited paper) T. Abbas, J. Kåredal, and F. Tufvesson: Measurement-Based Analysis: The Effect of Complementary Antennas and Diversity on Vehicle-to-Vehicle Communication, IEEE Antennas and Wireless Propagation Letters, T. Abbas, J. Nuckelt, T. Kürner, T. Zemen, C. Mecklenbräuker, and F. Tufvesson: Simulation and Measurement Based Vehicle-to-Vehicle Channel Characterization: Accuracy and Constraint Analysis (Accepted with major revision, 2014 to IEEE Transactions on Antennas and Propagations). T. Abbas: Measurement Based Channel Characterization and Modeling for Vehicle-to-Vehicle Communications, Series of licentiate and doctoral dissertations, ISSN X (No. 58), Department of Electrical and Information Technology, Lund University, Sweden, /12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 36

37 Selected publications M. Boban, J. Barros, and O. Tonguz, Geometry-based vehicle-to-vehicle channel modeling for large-scale simulation, IEEE Transactions on Vehicular Technology, Vol. 63, No. 9, November 2014 Mikael G. Nilsson et. al On Multilink Shadowing Effects in Measured V2V Channels on Highway, 2016 Mikael G. Nilsson et. al A Measurement-Based Multilink Shadowing Model for V2V Network simulations of Highway Scenarios, 2017 Mikael G. Nilsson et. al A Path Loss and Shadowing Model for Multilink Vehicle-to-Vehicle Channels in Urban Intersections, 2018 Mate Boban et. Al Multi-band Spatio-Temporal Characterization of a V2V Environment Under Blockage, /12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 37