Method and apparatus for forward error correction in packet networks
First Claim
1. A method for applying forward error correction to media packets in a transmission network, comprising the steps ofchoosing an error correcting code at a transmitter;
- generating a set of FEC packets, each FEC packet containing an offset bitmask associating the FEC packet with a media packet and containing a field sufficient to impart the chosen error-correcting code to at least one FEC-capable receiver;
sending the packet stream, consisting of media packets and FEC packets, to the FEC-capable receiver; and
decoding the packet stream at the FEC-capable receiver, generating media packets as a result.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for applying forward error correction in a transmission network includes the steps of choosing one of a plurality of possible error correction codes, using an appropriate field to encode a complete forward-error-correcting (FEC) code algorithm in each FEC packet to be transmitted. The packet stream, consisting of media packets and FEC packets can be sent to both FEC-capable and FEC-incapable receivers. Decoding methods are independent of the forward-error-correcting code transmitted. The sender can adapt the forward-error-correction code algorithm and the degree of error correction provided on a one-time basis or even more dynamically. Decoding and recovery at the receiver require no prior notification from the sender. Applying the FEC code algorithm to decode includes interrogating the bits in an offset bit mask in each FEC packet to yield links with media packets, and applying other fields of the FEC header to obtain instructions to recover lost data in one of the media packets. Based thereon, reiterative decoding of media packets ensures that lost data recoverable with combinations of media packets and FEC packets are recovered.
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Citations
13 Claims
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1. A method for applying forward error correction to media packets in a transmission network, comprising the steps of
choosing an error correcting code at a transmitter; -
generating a set of FEC packets, each FEC packet containing an offset bitmask associating the FEC packet with a media packet and containing a field sufficient to impart the chosen error-correcting code to at least one FEC-capable receiver; sending the packet stream, consisting of media packets and FEC packets, to the FEC-capable receiver; and decoding the packet stream at the FEC-capable receiver, generating media packets as a result. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for providing forward error correction in a transmission network for data packets transmitted therein, comprising:
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apparatus for providing media data packets for transmission; a transmission interface with the network; a forward-error-correcting code generator for preparing the media data packets and separable forward-error-correcting packets for transmission through said transmission interface into said network, said forward-error-correcting code generator being capable of operating with a plurality of algorithms for forward error corrections; an algorithm inserter for inserting one of the plurality of algorithms into said forward-error-correcting code generator; a bitmask source for providing to said forward-error-correcting code generator an offset bitmask for insertion in the protocol header, the offset bitmask associating a forward-error-correction packet with at least one media packet; a reception interface with said network; and apparatus for providing an error-corrected version of the media data packets received from the network through the reception interface, including a decoder capable of acquiring and using any of a plurality of algorithms for forward-error-correction received through the interface from the network. - View Dependent Claims (12, 13)
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Specification