Programmable H.263-Based Wireless Video Transceivers for Interference-Limited Environments

In order to exploit the nonuniformly distributed channel capacity over the cell area, the intelligent 7.3-kB programmable videophone transceiver of Table I is proposed, which is capable of exploiting the higher channel capacity of uninterfered, high-channel-quality cell areas, while supporting more robust, but lower bit-rate operation in more interfered areas. The system employed an enhanced H.263-compatible video codec. Since most existing wireless systems exhibit a constant bit-rate, the video codec's bit-rate fluctuation was smoothed by a novel adaptive packetization algorithm, which is capable of supporting automatic repeat request (ARQ)-assisted operation in wireless distributive video transmissions, although in the proposed lowlatency interactive videophone transceiver, we refrained from using ARQ. Instead, corrupted packets are dropped by both the local and remote decoders in order to prevent error propagation. The minimum required channel signal-to-interference-plus-noise ratio (SINR) was in the range of 8--28 dB for the various transmission scenarios of Table I, while the corresponding video peak-signal-to-noise ratio (PSNR) was in the range of 32--39 dB. The main system features are summarized in Table I. Index Terms---H.263-based video communications, interactive wireless video, QAM-based video transmission, video communications in interference-limited environments, video tranceivers. I