MICROWAVE RADIO COVERAGE FOR VEHICLE TO-VEHICLE AND IN-VEHICLE COMMUNICATION
*SIMULATING IN-CAR MICROWAVE PROPAGATION
*BLUETOOTH LINK SIMULATION RESULTS
*BLUETOOTH IN-CAR EXPERIMENTAL RESULTS
*VEHICLE TO VEHICLE COMMUNICATION
*Vehicle to vehicle communication and in vehicle
communication is important for intelligent transport
*Bluetooth radio frequency channel is used for in
*Bluetooth link is used for vehicle to vehicle to
*Bluetooth working on 2.45 GHz and LAN working at
64GHz are used at high frequency.
*To determine electromagnetic scattering from complex
,lossy die electric structure some simulation tools like
WIPL-D ,FEKO and SEMCAD are used.
*WIPL-D is based on the Method of Moments (MoM).
1)geometry of a structure as any combination of wires
2)structure’s current distribution
3)far-field radiation pattern
4)Near field distribution
5) multiport admittance at predefined feed points.
FEKO is also based on the Method of Moments.
FEKO The MoM, which scales poorly with frequency, has
been hybridized with two asymptotic high frequency
1) physical optics (PO)
2) uniform theory of diffraction (UTD)
This hybridization enables the solution of much larger
problems (in terms of wavelengths).
SEMCAD uses a Finite-Difference Time-Domain (FDTD)
kernel and focuses on main applications, namely near-
field analysis, antennas embedded in complex
environments, EMC/EMI applications and dosimetry.
*At 2.45 GHz, the simulation is performed using a quarter wave
antenna radiating inside the car structure.
*This transmitting antenna is located either on the dashboard or
in the rear boot.
*A metal sheet is also laid between the passenger cell and the
*A 10 cm diameter circular hole is perforated into this metal
sheet. Otherwise, the passenger cell is empty.
*Windscreens are considered fully transparent to RF signals and
the car body is simulated as a perfect conductor.
* Figures 2 and 3 show results respectively obtained using the
2.45 GHz radiating source (bright point) situated on the
dashboard or in the boot.
* They are presented with an overall dynamic range
representation of respectively 60 dB and 40 dB.
*From the dashboard, a fairly good RF coverage is obtained
over the whole structure including the imperfectly shielded
* An overall signal amplitude dynamic of 50 dB is deduced from
*Moving the receiving location a few centimetres apart, even in
the vicinity of the transmitting antenna, leads to signal
fluctuations in the order of 30 dB.
*This result can be compared to the huge number of
propagation modes that exist inside a large perfectly
*On figure 3, transmitting from the boot yields to different
results. The motor compartment radio coverage exhibits a
supplementary attenuation due to the presence of the metal
sheet separating the passenger cell from the motor
*The lower overall dynamic of the representation emphasizes
the fluctuations of signal propagated inside the car body.
*Within a platoon, car and truck drivers use information about the speed
and position of the preceding and following vehicles in order to elaborate
and update a real time driving solution.
*these equipments only track the first preceding vehicle to deduce its
speed and position.
*Nevertheless, this computed information remains on board the vehicle
that has performed the measurement.
*a platoon, the frontal road perception of the first vehicle is very
particular and highly significant. Thus, it seems to us, that this
information can be shared in real-time with the following vehicles within
*This concept has been named Electronic Millimetre Wave P re-View Mirror
(EPVM). Two RF links are considered.
*The first one uses a Bluetooth 2.45 GHz link, the second one uses a
modified extended AICC sensor.
*This last concept is illustrated by the artist’s view provided in figure 4.
Using a passive sub-reflector, some of the millimetric (76 GHz) RF power
available in the sensor is transmitted backwards behind the vehicle to
*The use of Bluetooth has been investigated in order to
evaluate its potential for some ITS applications.
*Simulating and experimenting these systems for
communicating inside a vehicle show that the propagation
channel is harsh but that it is possible to maintain, for the
chosen experimented locations a good radio-coverage inside
the whole car.
*For vehicle-to-vehicle communication, Bluetooth 1.1
standard available equipment seems also promising. Using
available PCMCIAs cards, video transmissions up to 100 m
have been achieved.
*Of course, the limited standard data rate means limited
video resolution and frame rate in comparison to the use of
the wide bandwidth provided by an AICC extended sensor.