Patent ID: 6108384
Filing Date: 2000-08-22
Classification: H03M,H04L

Abstract:
A data transmission method which varies an average transmission rate by transmitting frames, each of which has a fixed time length, and contains variable length transmitted data, said data transmission method comprising,at a transmitting side, the steps of:calculating an error detecting code of the transmitted data of each frame; andtransmitting frame data at a constant transmission rate, said frame data including the error detecting code, transmitted data and tail bits, and having undergone error correcting coding using a convolutional code and interleaving common to respective frames, andat a receiving side, the steps of:successively assuming frame by frame entire transmittable final bit positions of the frame data after having performed, on received frame data, deinterleaving common to respective frames, and carrying out to the assumed final bit positions error correcting decoding based on maximum likelihood decoding and calculation of an error detecting code of a transmitted data portion;deciding, at each final bit position during error correcting decoding, that the final bit position is the final bit position of the transmitted frame data if a difference between a maximum value of likelihoods of a plurality of decoded data sequence candidates with respect to the transmitted data sequence and a likelihood of a decoded data sequence obtained by terminating decoding with respect to the transmitted data sequence is in a predetermined range, and the calculated error detecting code agrees with a received error detecting code; andrecovering the variable length transmitted data based on a result obtained by the step of deciding.