Title :
Composite scheme LR+Th for decoding with erasures and its effective equivalence to Forney´s rule
Author :
Hashimoto, Takeshi
Author_Institution :
Dept. of Electr. Eng., Univ. of Electro-Commun., Tokyo, Japan
fDate :
1/1/1999 12:00:00 AM
Abstract :
For decoding with erasures, Forney´s scheme is known to be optimal in the sense that no other scheme can make the erasure probability Pers and undetected error probability Puer simultaneously smaller. We propose a scheme for erasure decision which tests the likelihood ratio as well as the likelihood itself and show that the attainable upper bounds on Pers and Puer are the same as those proved for the optimal scheme up to a constant factor. We also show that the scheme gives, when applied to convolutional codes, a bound which is related to the block-coding bound via Forney´s inverse concatenation construction. We show that this bound is the same as the one which naturally arises when we apply Raghavan and Baum´s (1998) optimal scheme to convolutional code
Keywords :
block codes; concatenated codes; convolutional codes; decision theory; decoding; error statistics; Forney´s inverse concatenation construction; Forney´s rule; block-coding bound; composite scheme LR+Th; convolutional code; convolutional codes; decoding; erasure decision; erasure probability; erasures; likelihood ratio; undetected error probability; upper bounds; Automatic repeat request; Block codes; Convolutional codes; Decoding; Error probability; Information theory; Memoryless systems; Performance analysis; Testing; Upper bound;
Journal_Title :
Information Theory, IEEE Transactions on