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Traffic Scheduling For Energy Sustainable Vehicular Infrastructure. Abdulla A. H., Ghada H. B., Terence D. T., Amire A. S. and Dongmei Z. IEEE Globecom 2010 proceeding. Presented by 劉美妙. Outline. Introduction System model and optimal energy bound Nearest fastest set (NFS) scheduler - PowerPoint PPT Presentation
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Traffic Scheduling For Energy Sustainable Vehicular Infrastructure
Abdulla A. H., Ghada H. B., Terence D. T., Amire A. S. and Dongmei Z.
IEEE Globecom 2010 proceeding
Presented by 劉美妙
OutlineIntroductionSystem model and optimal energy boundNearest fastest set (NFS) schedulerPerformance evaluationConclusions
IntroductionVehicular network infrastructure will eventually evolve into a
platform which will permit an even larger variety of mobile applications.
In many highway locations, setting up this type of infrastructure is difficult due to the unavailability or excess expense of wired electrical power.
An alternative to wired power connections is to operate some of the APs using an energy sustainable source such as solar or wind power.
Since multiple vehicles may be present in the AP coverage area, the question arises as to the order with which vehicles should be served.
As the energy available for the AP is limited, it is important to design energy efficient scheduling algorithms.
System model and optimal energy boundSingle roadside AP
Serving vehicles passing by in one directionSingle radio transceiverConnect to one vehicle at any given time for a time slot, Δt
Pdoze: power consumption in Doze modethe AP’s radio is placed into a Doze mode when traffic is not
being processed
Pt : AP transmission power at time ttransmit to vehicles using as small a transmit power as possiblesubject to satisfying the communication requests issued by the
passing vehicles
Minimize the total energyA standard exponential distance-dependent path loss
model is used.
power consumption in Doze mode
Energy used by AP to serve the demands of the vehicles
Nearest fastest set (NFS) schedulerNearest Fastest Set (NFS) Scheduler that uses received
knowledge of vehicle locations and velocities over a given time window
NFS: schedule vehicle requests when they are as close as possible to the AP.same distance: determined by velocity of the vehicles
In a given time slot, NFS decides the order with which vehicles will be served for a short duration of time
NFS consists of two execution phasesPreparation of candidate communication opportunities.Scheduling phase
Preparation of candidate communication opportunities.
NCLNv × tws=
Vehicle v1, R1=4, ws=5Select nearest locations
NFS Scheduler-phase I
t1 tws…
Time window
V1
VNv
… …
t1 t2 t3 t4 t5
v1
v2
v3
v4
AP
Dv1,t5Dv1,t3Dv1,t2Dv1,t1 Dv1,t4
Distance: Dv1, t3 < Dv1, t4 < Dv1, t5 < Dv1, t2 < Dv1, t1
1 1 11
NFS Scheduler-phase IIScheduling phaseresolves contention between vehicle requestsIn time slot t,If , then , else if
Compute weight:
t
v1 1 1 1
v2 1
v3 1 1
1
1
1
AP
t
The simulation time for each run is 600 time steps and the number of vehicles is 48.
The window size for the NFS and NO Schedulers is 10 time steps.
NFS scheduler performance for different traffic density
Performance evaluation
NFS scheduler performance for different σ
NFS schedule performance for different α
Density: 8 Vehicles per KM (125m apart)Average speed: 72KM/h
Performance evaluation
Different demand Different traffic density
Standard deviation σ = 4,Propagation path loss exponent α = 2,Density: 4 Vehicles per KM (125m apart)
Demand level R = 6, Average speed: 108KM/h
Compare with other scheduler
Different σ Different α20 times
5 times
Compare with other scheduler (cont.)
ConclusionsIn this paper, we have considered the problem of
satisfying vehicular communication requirements while minimizing the energy needed by the roadside access point.
proposed a Nearest Fastest Set (NFS) scheduler that uses vehicle location and velocity inputs to perform causal scheduling.
since multiple vehicles may be present in the AP coverage area, the question arises as to the order with which vehicles should be served.phraseas to something; as regards something關於 ;至於
AP
Dv1,tDv2,t
Dv3,t