1. Unequal Error Protection for Video Transmission over Wireless Channels
ECE738 Project Presentation
Chang, Hong Hong
05/09/2003

2. Outline Unequal Error Protection/ Unequal Loss Protection
Problem Formulation
Channel Model
RS code
Theoretical Results
Simulation Results
Conclusion

3. UEP/ULP
Video quality is determined by the packet loss behavior observed at the video decoder.
Time varying wireless channels
Time varying networking conditions
Limited transmission rate
Different priority source data

4. UEP Goal of UEP Some of algorithms
Assign unequal amounts of error correction /protection bits
To gain optimal quality in the receiver side
Some of algorithms
Rate Compatible Punctured Convolutional codes
Multiple description
Priority encoding transmission - unequal amount of FEC packets

5. Problem Formulation Use Reed-Solomon code as the channel coding
Given a fixed size of packet, how many protection bits/symbols can be added in the RS codeword to get the optimal quality in the receiver side?

6. Problem Formulation Optimization criteria Work need to do
Maximize expected PSNR
Minimize expected distortion
Maximize expected effective source rate (used in this project)
Work need to do
Channel model + RS coding -> Packet loss rate
Packet loss rate -> effective source rate

7. Channel Model
Good
Bad
PGB
PBG
Two state Markov Channel Model

8. Reed-Solomon (RS) code
The RS (n, k) channel code converts every k information symbols into an n-symbol block by appending n-k parity symbols.
Any error pattern with less than symbol errors can be corrected. 2t k
data
parity

9. Analysis Symbol error probability PB
Probability of i symbol errors within a block of n successively transmitted symbols
Packet loss rate
Effective source rate for one packet k*(1-PL)
Calculate expected effective source rate over several packets

10. Theory results-BSC

11. Theory results-BSC (contd.)

12. Simulation results (1)

13. Simulation results (2)

14. Simulation results (3)

15. Simulation results (4)

16. Conclusion
PB is smaller -> k is larger, better optimal effective source rate.
The simulation results are basically match with the theoretical results.