Date post: | 30-May-2015 |
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Upload: | krunal-siddhapathak |
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Prepared by:
Krunal Siddhapathak(10bec097)
* MICROWAVE RADIO COVERAGE FOR VEHICLETO-VEHICLE AND IN-VEHICLE COMMUNICATION
INDEX
*Introduction
*SIMULATING IN-CAR MICROWAVE PROPAGATION
*BLUETOOTH LINK SIMULATION RESULTS
*BLUETOOTH IN-CAR EXPERIMENTAL RESULTS
*VEHICLE TO VEHICLE COMMUNICATION
*CONCLUSION
*INTRODUCTION
*Vehicle to vehicle communication and in vehicle communication is important for intelligent transport system.
*Bluetooth radio frequency channel is used for in vehicle communication.
*Bluetooth link is used for vehicle to vehicle to communication.
*Bluetooth working on 2.45 GHz and LAN working at 64GHz are used at high frequency.
*SIMULATING IN-CAR MICROWAVE
PROPAGATION
SIMULATING IN-CAR MICROWAVE
PROPAGATION(contd.)*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).
*It defines:
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.
*SIMULATING IN-CAR MICROWAVE
PROPAGATION(contd.)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 techniques namely:
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.
*BLUETOOTH LINK SIMULATION RESULTS
*BLUETOOTH LINK SIMULATION
RESULTS(contd.)
*BLUETOOTH LINK SIMULATION
RESULTS(contd.)*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 motor compartment.
*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.
*BLUETOOTH LINK SIMULATION
RESULTS(contd.)* From the dashboard, a fairly good RF coverage is obtained over
the whole structure including the imperfectly shielded motor compartment.
* An overall signal amplitude dynamic of 50 dB is deduced from these results.
*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 conducting cavity.
*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 compartment.
* The lower overall dynamic of the representation emphasizes the fluctuations of signal propagated inside the car body.
*BLUETOOTH LINK SIMULATION RESULTS
*BLUETOOTH LINK SIMULATION
RESULTS(contd.)
*BLUETOOTH LINK SIMULATION
RESULTS(contd.)
*Vehicle to vehicle communication
*Vehicle to vehicle communication
* 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 the platoon.
* 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 following vehicles.
*CONCLUSION*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.
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