Error detection scheme for arq systems

摘要

An error detection and correction scheme for automatic repeat request (ARQ) systems in which multiple copies of a received data packet comprising a CRC field are compared to each other to determine the non-unanimous bit positions. If the number of bit positions thus determined lies under a threshold, tentative packets with all possible configurations at the non-unanimous bit positions are tested on validity by CRC check. In order to amount for the changes in the header fields between the multiple copies of a received data packet, the CRC fiels are calculated before and after modifying the variable header fields of at least some of multiple copies of said received data packets.