Adaptive Broadcast for Travel and Traffic Information Distribution Based on Inter-Vehicle Communicat...
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

Lars Wischhof et al. Technical University of Hamburg-Harburg, Hamburg, Germany PowerPoint PPT Presentation


  • 117 Views
  • Uploaded on
  • Presentation posted in: General

Adaptive Broadcast for Travel and Traffic Information Distribution Based on Inter-Vehicle Communication. Lars Wischhof et al. Technical University of Hamburg-Harburg, Hamburg, Germany. Presented by Long Vu CS598JH – Fall 07. Traffic and Travel Information System (TTI).

Download Presentation

Lars Wischhof et al. Technical University of Hamburg-Harburg, Hamburg, Germany

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Lars wischhof et al technical university of hamburg harburg hamburg germany

Adaptive Broadcast for Travel and Traffic Information Distribution Based on Inter-Vehicle Communication

Lars Wischhof et al.

Technical University of Hamburg-Harburg, Hamburg, Germany

Presented by Long Vu

CS598JH – Fall 07


Traffic and travel information system tti

Traffic and Travel Information System (TTI)

Self Organizing Traffic Information System (SOTIS)

How to broadcast information among cars efficiently?


Lars wischhof et al technical university of hamburg harburg hamburg germany

  • Challenges

    • Mobile nodes

    • Node density is not uniform

      • Highway vs. traffic jam

  • Possible solutions

    • Periodically broadcast with fixed broadcast interval

    • Adaptively tune broadcast interval

How to broadcast information among cars efficiently?


Lars wischhof et al technical university of hamburg harburg hamburg germany

Next…

  • Self-Organizing Traffic Information System

  • Provoked Broadcast

    • Provoked Broadcast

    • Provocation vs.Mollification

    • Influence of Distance on Provoked Broadcast

  • Simulation

    • Settings

    • Cumulated number of dropped packets

    • Required Bandwidth

  • Conclusion


Self organizing traffic information system

Self-Organizing Traffic Information System

  • All nodes in a segment broadcast their velocities to all other nodes in the same segment  all nodes can compute average velocity and put into TTI record of this segment

  • Transmission range: 1000m

  • Fixed broadcast interval: 5 seconds

No Segment

Leader

Intra-road segment communication


Self organizing traffic information system1

Self-Organizing Traffic Information System

Inter-road segments communication (SOTIS packet)

N = 100 km/500m = 200

Each record is the average velocity of cars in the corresponding segment


Lars wischhof et al technical university of hamburg harburg hamburg germany

Next…

  • Self-Organizing Traffic Information System

  • Provoked Broadcast

    • Provoked Broadcast

    • Provocation vs.Mollification

    • Influence of Distance on Provoked Broadcast

  • Simulation

    • Settings

    • Cumulated number of dropped packets

    • Required Bandwidth

  • Conclusion


Provoked broadcast 1

Provoked Broadcast (1)

  • Step 1: Each car broadcast its velocity to its neighbors in the same road segment  avg. velocity is computed

  • Step 2: Cars update TTI for this road segment. Put it into SOTIS packet

    • A TTI record has averagevelocity and time stamp

  • Step 3: Car broadcasts the SOTIS packet to neighboring road segments


Provoked broadcast 2

Provoked Broadcast (2)

  • Step 4: Upon receiving SOTIS packet, car updates TTI records in its memory (knowledge base)

  • Step 5: Depending on the difference between received SOTIS packet and its knowledge base, car performs provocation or mollification on broadcast interval


Lars wischhof et al technical university of hamburg harburg hamburg germany

  • Compare received SOTIS packet to car’s knowledge base:

    • Provocation

    • Mollification

vi- vi’

ti- ti’

Car’s Knowledge base

Received SOTIS packet


S distinct overlapped road segments

S Distinct Overlapped Road Segments

  • qinfo and qdate are constants


Provocation vs mollification

Provocation vs. Mollification

  • If wm,n < wmol T = T + tmol

  • If wm,n > wprov T = T - tprov

Too many constants and parameters !


How it actually works

How it Actually Works ?

Increase Tupd

Decrease Tupd


Interdependence of provocation and mollification

Interdependence of Provocation and Mollification

  • M close nodes (in trans. range)

  • Have a similar view of network

  • N broadcasts new information

  • All nodes provoke

  • Nodes are unsynchronized

  • A broadcasts, other nodes perform mollification


Lars wischhof et al technical university of hamburg harburg hamburg germany

Next…

  • Self-Organizing Traffic Information System

  • Provoked Broadcast

    • Provoked Broadcast

    • Provocation vs.Mollification

    • Influence of Distance on Provoked Broadcast

  • Simulation

    • Settings

    • Cumulated number of dropped packets

    • Required Bandwidth

  • Conclusion


Influence of distance on provoked broadcast

Influence of Distance on Provoked Broadcast

  • The farthest node in the broadcast range should broadcast next to utilize bandwidth

dtx,max: the max trans. range

If wm,n > wprov T = T – qdist(dtx)


Lars wischhof et al technical university of hamburg harburg hamburg germany

Next…

  • Self-Organizing Traffic Information System

  • Provoked Broadcast

    • Provoked Broadcast

    • Provocation vs.Mollification

    • Influence of Distance on Provoked Broadcast

  • Simulation

    • Settings

    • Cumulated number of dropped packets

    • Required Bandwidth

  • Conclusion


Simulation settings

Simulation Settings

No justification about

values of parameters

NS2 simulation


Cumulated number of dropped packets

Cumulated Number of Dropped Packets


Required bandwidth

Required Bandwidth


Conclusion

Conclusion

  • Pros

    • A threshold-based adaptive broadcast protocol

    • Tune broadcast interval according to changes of SOTIS packet

  • Cons

    • Too many control parameters


  • Login