Roadside infrastructure is traditionally assumed to be based on IEEE 802.15 which defines the various opportunistic and cognitive elements necessary for vehicle-specific mobility. However recent advances in wireless technology -- specifically, the fact the Beacons have become highly accessible both on commodity devices and in readily available software -- opens the path towards minimizing the size of roadside infrastructure while also simplifying individual nodes. This paper discusses a case when relatively fewer roadside network nodes are put to the task of having to collect image data from a much larger number of roadside cameras. Collection is happening via vehicles which are used as sync packets between camera and network nodes. Communication is happening solely via beacons using beacon stuffing when necessary. Special attention is paid to short-term communication and contention when wireless density is high.

1. Marat Zhanikeev
maratishe@gmail.com
maratishe.github.io
2016/02/22@ITS研＠北海道大学
PDF: bit.do/160222
for Roadside Infrastructure
#beacons
#beaconstuffing
#roadside
#vehicular
#autonomous
based on Wireless Beacons
Image-related Uses

2. 3 Types of Vehicular Nets
WiFi
3G
3G
802.11p
(WAVE)
GroupConnect Beacons
802.11a -n,ac
Beacon Frame
01 M.Zhanikeev+0 "Opportunistic Multiconnect with P2P WiFi and Cellular Providers" ...4G and Beyond, CRC (2015)
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 2/11
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3. Dense Wireless Spaces
03 X.Yang+0 "Throughput and Delay Limits of IEEE 802.11" IEEE Communication Letters (2002)
09 "Revolution WiFi: SSID Overhead Calculator" http://www.revolutionwifi.net (2016)
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 3/11
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4. Beacons: Broadcast vs Unicast
Broadcast better than Unicast
... at levels below flooding
0 2000 4000 6000 8000
Throughput (kbps)
P2P WiFi Unicast
Beacon Broadcast
P2P WiFi thru#220 Beacon thru#8858 Beacon fps#2480
Nodes#30 in 25x25m P2P WiFi Condition: wifi
• 30 nodes, but only 5
random nodes talk
• measure: with all collisions
and overhead, one2all
goodput
• P2P WiFi is represented by
WiFi Direct 01
01 M.Zhanikeev+0 "Opportunistic Multiconnect with P2P WiFi and Cellular Providers" ...4G and Beyond, CRC (2015)
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 4/11
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5. Beacon Density (model)
0 4000 8000
FPS
0
0.4
0.8
Lossprobability
Beacon loss probability curve
• model of the conditions in the previous page
• simpler to model beacon-based data
exchange
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 5/11
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6. Simulated Roadside Section
Roadside
beacon
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 6/11
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7. Images ～= Video Streaming
• for simple images, assume that only the I-Frame (1st) is used
• otherwise, aiming at (even if low-bitrate) video streaming
0 20 40 60 80 100
Time sequence
0
20
40
60
80
100
Framesize(kb)
SVCVBR
0 20 40 60 80 100
Distribution sequence
0
20
40
60
80
100
Framesize(kb)
02 M.Zhanikeev+0 "How variable bitrate video formats can help P2P streaming..." Springer J. of Elec. Commerce (2015)
08 R.Chandra+3 "Beacon-Stuffing: Wi-Fi without Associations" 8th IEEE HotMobile (2007)
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 7/11
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8. Simulation Results
0 2 4 6 8 10 12 14
Frame in GOP
0
1
2
3
4
5
6
7
8
No.ofparallelchannels
0.7
0.3
0.2
0.2
0.1
0.1
0.1
0.1
0.6
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.6
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.2
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.2
0.2
0.1
0.1
0.1
0.1
0.1
0.5
0.2
0.2
0.1
0.1
0.1
0.1
0.1
0.4
0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.3
0.1
0.1
0.1
0.1
0
0
0
0.3
0.1
0.1
0.1
0.1
0
0
0
0.3
0.1
0.1
0.1
0.1
0
0
0
0.1
0
0
0
0
0
0
0
• 10 beacons (9 cars + 1 roadside)
• parallel channels: up
to 11 (5-6 are feasible and
strong) in practice
◦ logic: randomly select a
channel and send your
beacon
◦ not on commodity
hardware (yet)
• bullets = loss
probability (zero = no
value = all lost)
• other cases https://
goo.gl/B0qACx
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 8/11
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9. Wrapup: The Big Picture
Service
Provider
Roadside
beacon
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 9/11
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10. That’s all, thank you ...
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 10/11
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11. (donotforget) Connected Cars
3G
3G
3G
Basic
Components
Conventional
Connected
Cars
M.Zhanikeev -- maratishe@gmail.com Image-Related Uses for Roadside Infrastructure based on Wireless Beacons -- bit.do/160222 11/11
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