A measurement study of vehicular internet access using in situ wi fi network
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A Measurement Study of Vehicular Internet Access using In Situ Wi-Fi Network. Vladimir Bychkovsky, Bret Hull, Allen Miu, Hari Balakrishnan and Samuel Madden Presented By: Galileo Namata. Basic Problem.

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A Measurement Study of Vehicular Internet Access using In Situ Wi-Fi Network

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A measurement study of vehicular internet access using in situ wi fi network

A Measurement Study of Vehicular Internet Access using In Situ Wi-Fi Network

Vladimir Bychkovsky, Bret Hull, Allen Miu, Hari Balakrishnan and Samuel Madden

Presented By: Galileo Namata


Basic problem

Basic Problem

  • Can a “grassroots” wireless Internet service, provided by users who “open-up” their 802.11 (Wi-Fi) AP, be created for mobile clients?

  • Can such an unplanned network service provide reasonable performance to clients at vehicular speeds?

  • What is the expected performance for users in automobiles as they move?


Motivation

Motivation

  • Cartel

    • Cartel is a mobile sensor computing system designed to collect, process, deliver and visualize data from in car sensors

    • Reference:

      • Bret Hull, Vladimir Bychkovskiy, Kevin Chen, Michel Goraczko, Eugene Shih, Yang Zhang, Hari Balakrishnan, Samuel Madden. CarTel: A Distributed Mobile Sensor Computing System. In Proceedings of SenSys, 2006. http://db.csail.mit.edu/pubs/fp02-hull.pdf


Cartel in a nutshell

CarTel In A Nutshell

  • Computer

    • 266 MHz with 128 MB of RAM and 1 GB of flash memory

  • Varied Sensors

    • GPS Receiver, OBD-II Interface, Wi-Fi Interface, Digital Camera


Cartel in a nutshell1

CarTel In A Nutshell


Cartel in a nutshell2

CarTel In A Nutshell

  • Commute Time Analysis

    • Researcher shortened his commute

  • Traffic Hot Spot Heuristic

    • Identify Traffic Areas automatically

  • Image Acquisition

    • Google Maps with Pictures

  • Wi-Fi Measurement

  • Automotive Diagnostics


Cartel example

CarTel Example


Communication

Communication

  • CarTel data is set up to be automated

    • Don’t need to be plugged in to get data

    • Want to be able to get current data

  • Use In Situ Wi-Fi Networks

    • In Situ – Latin “in the place”

    • All data, sent through open networks

      • Updates and queries to CarTel nodes

      • Data from sensors to main server


What s the performance

What’s the Performance?

  • Experiment:

    • Use CarTel system in and around Boston Metropolitan Area and Seattle

      • 9 cars total, 290 “drive hours”

    • Measure Time For:

      • Scan

      • Association

      • Address Configuration

      • Single End to End Ping

      • Connectivity and uploads


Network activity timeline

Network Activity Timeline


Geographic coverage

Geographic Coverage


Ip address acquisition latency

IP Address Acquisition Latency


Effects of speed

Effects of Speed


Ap connectivity

AP Connectivity


Throughput

Throughput


Related work

Related Work

  • Ott and Kutscher – Controlled experiment measuring network connection from fixed test bed

  • Gass et al – Similar measurement but in California desert

  • “War Driving Maps”


Wardriving

Wardriving


Discussion

Discussion

  • Open Wi-Fi Networks

    • Don’t wanna get sued

      • “Safe Harbor” Laws

    • Don’t wanna get in trouble with ISP

      • Fon System (http://en.fon.com)

    • Public Free Internet?

      • Google in SF

    • Don’t Wanna Get Hacked?

      • Specialized, easy to manage hardware


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