ultra-wideband channel model for intra-vehicular wireless sensor networks c. umit bas electrical and...
Post on 17-Dec-2015
214 Views
Preview:
TRANSCRIPT
Ultra-Wideband Channel Model for Intra-Vehicular Wireless
Sensor Networks
C. Umit BasElectrical and Electronics Engineering , Koc University
History of In-Vehicle Networking
Early days of automotive electronicsEach new function implemented as a stand-alone ECU, subsystem containing a microcontroller and a set of sensors and actuators
Data exchanged between point-to-point links
sensor sensor
ECU
Body Control Module
ECU
History of In-Vehicle Networking
In the 1990sIncrease in the number of wires and connectors caused weight, cost, complexity and reliability problems
Developments in the wired communication networks
sensor
ECU
sensoractuat
orsensor
ECUECU
Body Control Module
History of In-Vehicle Networking
In the 1990sIncrease in the number of wires and connectors caused weight, cost, complexity and reliability problems
Developments in the wired communication networks
Multiplexing communication of ECUs over a shared link called bus
sensor
ECU
sensoractuat
orsensor
ECUECU
Body Control Module
History of In-Vehicle Networking
TodayIncreases in number of sensors as electronic systems in vehicles are replacing purely mechanical and hydraulic systems causes weight, cost, complexity and reliability problems due to wiring
Advances in low power wireless networks and local computing
sensor
ECU
sensoractuat
orsensor
ECUECU
Body Control Module
sensor sensor
sensor
sensor
sensorsensor
ECU
sensor
History of In-Vehicle Networking
TodayIncreases in number of sensors as electronic systems in vehicles are replacing purely mechanical and hydraulic systems causes weight, cost, complexity and reliability problems due to wiring
Advances in low power wireless networks and local computing
Intra-Vehicular Wireless Sensor Networks (IVWSN)
sensor
ECU
sensoractuat
orsensor
ECUECU
Body Control Module
sensor sensor
sensor
sensor
sensorsensorsensor
Motivation for Intra-Vehicular Wireless Sensor
NetworksProvide savings in
Part cost
Cost of assembly, repair and maintenance
Fuel consumption
Decreases cost of change/inflexibilityCabling connectivity has little design flexibility and upgrades
Enable new sensor technologies to be integrated into vehicles
E.g. tire pressure monitoring systems, intelligent tire
Replace current sensors not functioning well enough due to cabling.
IVWSN: Distinguishing Characteristics
Tight interaction with control systemsSensor data used in the real-time control of mechanical parts in different domains of the vehicles
Very high reliabilitySame level of reliability as the wired equivalent
Energy efficiencyRemove wiring harnesses for both power and data
HeterogeneityWide spectrum for data generation rate of sensors in different domains
Harsh environmentLarge number of metal reflectors, a lot of vibrations, extreme temperatures
Short distanceMaximum distance in the range 5m-25m
What is UWB?
Transmission from an antenna for which the emitted signal bandwidth exceeds the lesser of 500MHz and 20% of the center frequency.
Motivation for Ultra-Wideband
Vehicle control systems requireVery high reliability,
Strict delay guarantee.
UWB providesResistance to multipath fading,
Resistance to power loss due to lack of line of sight,
Resistance to interference,
Robust performance at high data rate with very low transmit power.
Wireless Channel Measurements
Building a detailed model for IVWSN requiresClassifying the vehicle into different parts of similar propagation characteristics
Collecting multiple measurements at various locations belonging to the same class
engine
beneath chassis
passenger compartment
trunk
Literature Review
Measurement Setup
Agilent 8719ES Vector Network Analyzer
3.1 GHz to 10.6 GHz using 1601 points
Measurement Locations
18 transmitter locations & 1 receiver location
At each location 9 antenna positions on 3x3 square grids with 5 cm spacing
Totally 81*18 measurement points
Data Processing
Large & Small Scale Fading Statistics
Large-Scale Statistics81 measurements at each location averaged to obtain the small-scale averaged PDP (SSA-PDP)
Large-scale statistics derived by using 18 SSA-PDP
Small-Scale StatisticsVariations of 81 Local PDP around SSA-PDP used to derive small-scale statistics
Large Scale Statistics
Modeled by using small scale averaged power delay profiles (SSA-PDP) for 18 locations
Path Loss Model
General Shape of Impulse Response
Modified Saleh-Valenzuela Model
cluster amplitude
ray decay rate
inter-arrival time of clusters
Small Scale Statistics
Characterized by fitting amplitude values of 81 local PDP to alternative distributions
Distribution of Amplitudes for Delay Bins
σ of Lognormal Distributions
σ is independent of time
σ of Lognormal Distributions
means of σ have no trivial relation with distance
σ of Lognormal Distributions
Small scale fading of different delays is not correlated
Susceptibility of Large-Scale Statistics
Susceptibility of Small-Scale Statistics
Regeneration of Statistical Channel Model
Model Validation – Qualitative Comparison
Measured Power Delay Profiles Simulated Power Delay Profiles
Model Validation – Quantitative Comparision
Conclusions
Intra-vehicular wireless sensor networksProvide cost reduction
Enable new sensor technologies to be integrated in vehicles
Channel characteristics beneath the chassisLarge scale statistics: path loss, power variation,
General shape of impulse response: modified Saleh-Valenzuela model
Small scale statistics
Proposed model validated with both qualitative and quantitative comparisons
Publications
C. U. Bas and S. C. Ergen, “Ultra-Wideband Channel Model for Intra-Vehicular Wireless Sensor Networks Beneath the Chassis: From Statistical Model to Simulations”, IEEE Transactions on Vehicular Technology, vol. 62, no. 1, pp. 14-25, January 2013. [pdf | link]
U. Demir, C. U. Bas and S. C. Ergen, "Engine Compartment UWB Channel Model for Intra-Vehicular Wireless Sensor Networks", IEEE Transactions on Vehicular Technology, vol. 63, no. 6, pp. 2497-2505, July 2014. [pdf | link]
C. U. Bas and S. C. Ergen, “Ultra-Wideband Channel Model for Intra-Vehicular Wireless Sensor Networks”, IEEE WCNC, April 2012. [pdf | link]
32
Thank You!
QUESTIONS?
Umit Bas: cbas@ku.edu.tr
Wireless Networks Laboratory: http://wnl.ku.edu.tr
top related