| 摘要 |
A repetitive transmission technique with time diversity which provides improved signal-to-noise ratio (SNR) in the presence of packet loss. Time shifts are introduced between N versions of a particular block of information to be transmitted, and the time-shifted versions are encoded in a set of N encoders and transmitted as N packets. The time shift introduced between a given pair of the N versions corresponds to approximately 1/N of the time duration of a particular one of the versions. The SNR of a composite reconstructed signal generated from the N packets with the introduced time shift in a receiver of the system is approximately the same as would be obtained using a set of N independent encoders to generate the plurality of packets without the introduced time shifts. The gain in the SNR of the composite reconstructed signal attributable to the introduction of the time shifts is 10 log10N', where N'=1, . . . N is the total number of the N packets actually received at the system receiver. A further improvement in SNR performance may be obtained by introducing quantization error compensation, in which quantization error from the encoding of a given one of the versions is successively combined with subsequent versions prior to encoding of those versions.
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