Visual Media Coding and Transmission

4.8 Modeling the DVC Decoder for Error-prone Wireless Channels

A number of independent studies have been carried out in relation to the performance of DVC over noisy and error-prone transmission media. The effects of data corruption in the Wyner–Ziv-encoded bitstream and the key-frame stream were discussed in detail in Section 4.7, using a packet-based network for simulations. The objective of the research activity discussed in this section is to design an improved model for the Wyner–Ziv decoder, to enhance the RD performance when operated over error-prone channels. The designed model will then be implemented on the VISNETITDWZ codec for a comparative analysis. This research concentrates on a W-CDMA wireless channel scenario transmitting the encoded Wyner–Ziv bitstream.

Figure 4.38 Overall RD performance for packet loss in key-frame and WZ-frame corruption for the Foreman and Hall Monitor sequences

For a wireless channel, time-varying multipath fading is considered the main challenge in designing communication systems. The modifications to the decoding algorithm necessary to compensate for the adverse channel effects will be discussed in this section. The effects of data corruption on transmission of the key frames will also be outlined, and another modification to the Wyner–Ziv decoder will be presented, by developing a new error model for the key frames. A packet drop simulator ...