Combined Source-Channel Coding for Wireless Transmission of H.263 Coded Video

Abstract

With the current emphasis on wireless communications access within the telecommunications community, there has been increasing interest in wireless transmission of multimedia services and, in particular, digital video. However, a significant obstacle to providing a reasonable quality of service (QoS) in this situation is the associated high compression rate required for digital video transmission over typically bandwidth-limited wireless channels, such as the mobile radio channel. The resulting compressed bitstreams are rendered extremely sensitive to channel errors, which can be severe in representative wireless links due to fading, multipath and other channel impairments. In order to protect against these channel error effects, some form of forward error-control (FEC) coding must be employed. Appropriate FEC coding approaches must be carefully selected and implemented; an important requirement is that they must adequately protect the compressed information bitstream, according to the characteristics of the given channel, without excessive throttling of the source coding rate to accommodate the coding overheads.