V2x wireless channel modeling for connected cars Taimoor Abbas Volvo Car Corporations taimoor.abbas@volvocars.com
V2X Terminology Background I2N P2N P2I V2N V2I V2P V2V 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 2
Wireless channel Background Propagation channel Radio Transmit Receiver channel antenna antenna 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
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
Propagation mechanism Background i r Typical communication scenario 1 2 t Reflection and Diffraction transmission Line-of-sight (LOS) component Scattering Waveguiding Multipath components 5
Propagation mechanism (cont.) Background If we assume the TX/RX antennas to be isotropic being in free space, Path loss d A RX 2 = P P RX TX 4 d d 2 ( ) 4 = L free d Large scale fading Small scale fading 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 6
V2V vs v2i V2X Channel 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 7
Doppler shift for v2v 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 8
Key Differences in V2V Channel Modeling V2X Channel LOS: Line-Of-Sight OLOS: Obstructed Line-Of-Sight NLOS: Non Line-Of-Sight Multilink g 1 g 2, XC90 g 2, Truck d r, XC90 d r, Truck W r d t XC90 Black Truck Blue g 2, XC90 W t S60 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 9
V2X Channel Measurements Modeling 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 10
Channel Sounder Modeling 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 11
Measurement based modeling Note: • Measurement tool always has certain limitations • It is necessary to keep those limitations 2 3 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 1 4 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 12
Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measure- ments 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 13
Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measure- ments 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 14
Measurement campaign step by step Antenna calibration Channel sounder mounting Conduction measure- ments 6/12/2018 SUMMER SCHOOL ON 5G V2X COMMUNICATIONS - TAIMOOR.ABBAS@VOLVOCARS.COM 15
General observations – v2v measurements Time-delay characteristics: Houses, road signs etc. RX Discrete comp. LOS t = 1.5 s t = 5.3 s t = 5.6 s t = 1.3 s t = 6.2 s t = 5.8 s t = 1 s t = 6 s t = 4.9 s t = 0.8 s t = 6.4 s t = 5.1 s t = 4.5 s t = 1.7 s t = 4.7 s t = 0.6 s t = 1.9 s t = 4.3 s t = 4.1 s t = 3.8 s t = 2.1 s t = 3.6 s t = 3.4 s t = 2.3 s t = 3.2 s t = 3 s t = 2.5 s t = 6.6 s t = 2.8 s t = 0 s t = 7.1 s t = 7.9 s t = 7.7 s t = 0.2 s t = 7.5 s t = 7.3 s t = 0.4 s t = 8.1 s t = 6.9 s Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Power Diffuse comp. Other vehicles TX 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 400 • Rapidly varying channel Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] Propagation distance [m] 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
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