Augmenting Reed-Solomon coding with retransmission for error recovery in 3G video broadcasts

Abstract

The error-prone nature of the radio channel is the major challenge in servicing video streams over cdma2000 broadcast networks. The MAC protocol for broadcast and multicast services (BCMCS) in cdma2000 specifies forward error correction using Reed-Solomon coding, which is effective in recovering from bursts of errors. However, its performance degrades significantly when channel conditions are bad, a frequent occurrence at the edge of the coverage area, reducing the availability of high-speed broadcasts. We propose an error recovery scheme and a scheduling algorithm based on the use of slots saved by changing to a Reed-Solomon code with a lower parity overhead. Within the fixed transmission budget thus created, corrupted packets are retransmitted in a priority order determined by a utility function that is derived from the map of the error control block at each mobile, and which also considers the number of mobiles that did not receive each lost packet. Simulation results show the effectiveness of the proposed scheme in improving the quality of high-data-rate MPEG-4 video streams over a range of channel conditions. Copyright (C) 2007 John Wiley & Sons, Ltd.