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

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

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

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

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?

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

Channel Model Good Bad PGB PBG Two state Markov Channel Model

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

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

Theory results-BSC

Theory results-BSC (contd.)

Simulation results (1)

Simulation results (2)

Simulation results (3)

Simulation results (4)

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