Method for concatenated convolutional encoding and interleaving
View Patent ↗A method and apparatus encode a source data stream via convolutional encoding. Plural encoded data streams are interleaved and transmitted on plural transmission channels. Data groups generated via convolutional encoding are interleaved via time-interleaving functions to disperse selected bits within puncture groups of the data groups, bits in between data groups, and bits in selected sets of data groups to facilitate reconstruction of the source data stream from at least a portion of the interleaved data stream received on at least one transmission channel. The time-interleaving functions are selected to facilitate reconstruction of the source data stream from one transmission channel following continuous blockage. Subsets of bits of puncture groups are selected to allow reconstruction of the source data stream from more than one of the transmission channels using a minimum number of subsets. Multiple combinations of subsets can be received on both transmission channels to reconstruct the source data stream following blockage of one channel. Decoding is performed via a Viterbi decoder.
1. A method of interleaving a source data stream for transmission comprising the steps of:
encoding said source data stream to generate an output data stream using a selected coding scheme having a selected code rate, said output data stream being characterized as a series of data groups, each of said data groups comprising a plurality of higher rate data groups, each of said higher rate data groups having a higher code rate with respect to said selected code rate;
interleaving said data groups in accordance with a plurality of time-interleaving functions to disperse said bits in said data groups within said output data stream and generate an interleaved data stream; and
demultiplexing said interleaved data stream for transmission as separate transmission groups, said time-interleaving functions being selected to disperse different groups of bits in said output data stream selected from the group consisting of said bits in one of said higher rate data groups, said bits in adjacent said data groups, and said bits in selected sets of said data groups to facilitate reconstruction of said source data stream from at least a portion of said interleaved data stream received on at least one of said transmission groups.
2. A method as claimed in claim 1 , further comprising transmitting said separate transmission groups to provide time diversity.
3. A method of interleaving a source data stream for transmission comprising the steps of:
encoding said source data stream to generate an output data stream using a selected coding scheme having a selected code rate, said output data stream being characterized as a series of data groups, each of said data groups comprising a plurality of higher rate data groups, each of said higher rate data groups having a higher code rate with respect to said selected code rate;
interleaving said data groups in accordance with a plurality of time-interleaving functions to disperse said bits in said data groups within said output data stream and generate an interleaved data stream; and
transmitting said interleaved data stream on at least one transmission channel, said time-interleaving functions being selected to disperse different groups of bits in said output data stream selected from the group consisting of said bits in one of said higher rate data groups, said bits in adjacent said data groups, and said bits in selected sets of said data groups to facilitate reconstruction of said source data stream from at least a portion of said interleaved data stream received via said at least one transmission channel.
4. A method of interleaving data for transmission comprising the steps of:
encoding a source data stream to generate a single output data stream using a selected coding scheme having a selected code rate, said output data stream comprising a first transmission group and a second transmission group each having data groups, said data groups comprising selected bits from the source data stream; and
interleaving said first transmission group and said second transmission group with interleaving functions selected to maximize recovery of said source data stream from at least one of either of said first transmission group and said second transmission group when said bits from said source data stream are dropped during transmission of the output data stream;
wherein said first transmission group and said second transmission group each comprise substantially the same bits from the source data stream.
5. A method as claimed in claim 4 , further comprising delaying transmission of said second transmission group with respect to transmission of said first transmission group on a single transmission link for time diversity.