Title :
Very low variable-rate convolutional codes for unequal error protection in DS-CDMA systems
Author :
Lientz, Andrew ; Villasenor, John
Author_Institution :
Dept. of Electr. Eng., California Univ., Los Angeles, CA, USA
fDate :
7/1/1997 12:00:00 AM
Abstract :
Convolutional codes based on Hadamard sequences can achieve both orthogonality and variable rate. In contrast with other convolutional coding techniques, these codes incur no processing gain penalty in direct-sequence code-division multiple-access (DS-CDMA) systems. We describe a class of such codes called “telescopic protection codes”. These codes enable variable-rate error protection in the manner of rate-compatible punctured-convolutional (RCPC) codes, but preserve the Hadamard orthogonality properties necessary to maintain processing gain that RCPC codes lack
Keywords :
Gaussian channels; binary sequences; code division multiple access; convolutional codes; error correction codes; image coding; pseudonoise codes; spread spectrum communication; variable rate codes; AWGN channels; DS-CDMA systems; Hadamard orthogonality properties; Hadamard sequences; RCPC codes; compressed image transmission; convolutional coding; direct sequence code division multiple access; processing gain; rate compatible punctured convolutional codes; telescopic protection codes; unequal error protection; variable rate error protection; very low variable-rate convolutional codes; Autocorrelation; Bit error rate; Convolutional codes; Costs; Error correction; Error correction codes; Forward error correction; Multiaccess communication; Protection; Viterbi algorithm;
Journal_Title :
Communications, IEEE Transactions on
