Improving Wireless Multimedia Quality using Header Detection with Priors

Recent wireless multimedia studies have revealed that forward error correction (FEC) on corrupted packets yields better bandwidth utilization and lesser delay than retransmissions. To facilitate FEC decoding at a wireless receiver, it is desirable to relay maximum number of (error-free and corrupted) packets to the receiver´s application layer. To that end, most cross-layer multimedia schemes perform partial checksum only on packet headers. However, even with a partial checksum, bursty wireless errors introduce frequent header corruptions, thereby causing considerable packet drops. In this paper, we extend our work in [1], which proposed receiver-based schemes to correct a packet´s critical (and corrupted) header fields. This paper: (a) poses header detection as the well-known decision theoretic problem of detecting known parameters in noise, (b) evaluates two detectors using bit-error traces collected over an 802.11b network, (c) provides throughput results for the detectors, and (d) uses video in conjunction with FEC as an example to highlight the efficacy of the proposed schemes. We show that header detection provides significant improvements in throughput and video quality over the conventional UDP/IP protocol stack.