A decoding method for Tornado‐type codes utilizing error packets

Satellite communications is suitable for multicast communications which can achieve one-to-many delivery because it can broadcast to multiple receiving stations over a wide area. However, packet retransmission is inefficient for satellite communications because of its large delay and bit error rate. In order to avoid packet retransmission, FEC (forward error correction) exploiting error correcting codes have been put to practical use in satellite multicasting. Tornado-type codes are well known as a kind of error correcting codes suitable for multicasting. Tornado-type codes are encoded and decoded in packets. As a result, they are effective for combatting packet losses by buffer overflow or congestion control. Furthermore, their coding and decoding have low time complexity. On the other hand, the bit errors in the packet are processed as a packet loss in decoding because the Tornado-type codes are decoded packet-wise. In this paper, we propose an effective decoding method for bit errors in the packets for Tornado-type codes. We show by computer simulation that the proposed method is effective in bit error environments. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(10): 57– 66, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20361