Interlogics

1
Wireless Video Transmission System
June 2004 Global Information and
Telecommunication Studies Waseda
University Takuro Sato
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Outline

• Wireless LAN Standard and Technology
• N to M Video transmission system
• Protocol of N to M Video system
• Video coding technologies
• FEC performance for 11b
• Evanescent system
• Demonstration for 11a, 11b and Evanescent system

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Wireless Standard and Technology
Narrow area
LAN
IEEE802.11a,Hipwe LAN,MMAC(OFDM)
Video transmission
IEEE802.11g
Low Mobility
IEEE802.20
High rate
IEEE802.11b(CCK)
QoS
IEEE802.15.3
IEEE802.16
Mobility
IP
Evanescent
High Mobility
Cellarer(CDMA) 3GPP,cdma2000
IP Mobile phone
Wide area
Cellular
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N to M video transmission system
Master
Master
Server
Client
Client
Client
Client
Network
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Protocol Configuration
CH assignment
Application
Mode selection
Encoder/Decoder
PC System
Data conversion
Port Driver
Data frame processing
ARQ(CRC)
802.11 MAC
802.11a,b,g,n
Physical
Layer
(FEC)
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Robust Image Encode/Decoding technology
Robust image encoding and decoding technologies
against burst error and high packet loss
environments.

• Space localization technology against erroneous
  picture data
• Time localization technology against erroneous
  picture data
• Concealment technology against erroneous picture
  data

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Space localization technology
Protection of error propagation in successive
coded data following erroneous data.

• Segmentation of video data frame by short slice.
• Reversible Variable Length Coding.
• when detecting an erroneous data, decoder
  reads data from next marker with backward until
  detecting erroneous data.
• Extended header by re-assignment of significant
  data of horizontal size,vertical size,picture
  coding type,etc.

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Time localization technology
Protection of error propagation on sequential
time by picture prediction algorithm

• Adaptive INTRA refresh
• Periodic insertion of intra coding data into
  motion compensation picture
• GOP structure
• - IBB picture Not use forward P prediction
  picture
• - Short GOP Decrease forward prediction
  picture

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Concealment technology for picture data error
Concealment of error picture frame using the
decoded picture.

• Reuse the previous picture frame
• Concentration of significant data at the front
  part of the picture frame

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Error correction capability under multi-path
fading environment using IEEE802.11b
No RS
1.E-03
RS
No RS with diversity
1.E-04
RS with diversity
1.E-05
BER
1.E-06
1.E-07
1.E-08
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14
16
18
20
22
24
26
RS(511.495)
S/NdB
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Evanescent wave Spectrum Characteristic
Shield room
desk
Exciter
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50cm
50cm
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10cm