METHOD FOR PACKET-LEVEL FEC ENCODING, IN WHICH ON A SOURCE PACKET-BY-SOURCE PACKET BASIS, THE ERROR CORRECTION CONTRIBUTIONS OF A SOURCE PACKET TO A PLURALITY OF WILDCARD PACKETS ARE COMPUTED, AND THE SOURCE PACKET IS TRANSMITTED THEREAFTER

• US 6,609,223 B1
• Filed: 04/06/2000
• Issued: 08/19/2003
• Est. Priority Date: 04/06/1999
• Status: Expired due to Term

• Current Assignee: KenCast Inc.
• Original Assignee: KenCast Inc.
• Inventors: Wolfgang, H. Lewis
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US09/544,161
• Time in Patent Office: 1,230 Days
• Field of Search: 714/752, 714/755, 714/776
• US Class Current: 714/752
• CPC Class Codes: H03M 13/00 Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes error detection or error correction for analogue/digital, digital/analogue or code conversion H03M1/00 – H03M11/00; specially adapted for digital computers G06F11/08; for information storage based on relative movement between record carrier and transducer G11B, e.g. G11B20/18; for static stores G11C
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00

Abstract

A method is provided for encoding a stream of source packets, in which a plurality of k source packets are packet-level forward error correction encoded to form a plurality of n-k error-correcting wildcard packets, wherein the k source packets and n-k wildcard packets are to be transmitted to a receiver. After the arrival of each source packet, for each byte of the source packet, the respective error correction contributions to the corresponding bytes of the plurality of wildcard packets are computed. The source packet is transmitted to the receiver without waiting for the arrival of another source packet of the plurality of source packets. For each wildcard packet byte, the error correction contribution of the source packet is summed in an accumulator. After the error correction contributions have been computed using all k source packets and summed for all n-k wildcard packets, the wildcard packets are transmitted to the receiver.

Claims

1. A method for encoding a stream of source packets, in which a plurality of k source packets are packet-level forward error correction encoded to form a plurality of n-k error-correcting wildcard packets, the k source packets and n-k wildcard packets to be transmitted to a receiver, comprising the steps of:

after the arrival of each source packet, for each byte of said source packet, computing the respective error correction contributions to the corresponding bytes of said plurality of wildcard packets;

transmitting said source packet to the receiver without waiting for the arrival of another source packet of said plurality of source packets;

for each wildcard packet byte, summing said error correction contribution of the source packet in an accumulator;

after the error correction contributions have been computed using all k source packets and summed for all n-k wildcard packets, transmitting the wildcard packets to the receiver.

2. A method for encoding a stream of source packets, in which a plurality of k source packets are packet-level forward error correction encoded to form a plurality of n-k error-correcting wildcard packets, the k source packets and n-k wildcard packets to be transmitted to a receiver, comprising the steps of:

after the arrival of each source packet, for each byte of said source packet, computing the respective error correction contributions to the corresponding bytes of said plurality of wildcard packets;

transmitting said source packet to the receiver without waiting for the arrival of another source packet of said plurality of source packets;

for each wildcard packet byte, summing said error correction contribution of the source packet in an accumulator, but if no source packet has arrived within a predetermined period of time after a previously-arriving packet k′

, the remaining k-k′

source packets are assumed to be zero, resulting in an error correction contribution of zero for those k-k′

packets;

after the error correction contributions have been computed using the k′

source packets and summed for all n-k wildcard packets, transmitting the wildcard packets to the receiver.

3. A method according to claim 2, wherein the number of wildcard packets computed and transmitted, as compared to the n-k wildcard packets, are proportional to the k′

actually arriving packets, as compared to the expected k source packets.