On maximum length convolutional codes under a trellis complexity constraint
Journal of Complexity - Special issue on coding and cryptography
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Searching for high-rate convolutional codes via binary syndrome trellises
ISIT'09 Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 2
New constructions of low-complexity convolutional codes
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
New constructions of high-performance low-complexity convolutional codes
IEEE Transactions on Communications
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For the class of rate k/(k+1) convolutional codes, Yamada et al. (1983) proposed an efficient maximum-likelihood decoding algorithm called the YHM algorithm. In order to reduce the complexity of the YHM algorithm, this paper presents two techniques for simplifying the trellis diagram used in the YHM algorithm. We further observe that the proposed techniques effectively reduce the complexity of the YHM algorithm for two classes Ξ and Ξf (which is a subclass of Ξ) of rate k/(k+1) convolutional codes. The construction of codes in these classes is also discussed. It is shown that Ξ codes with d free=3,4 can be obtained by simple construction. A code search algorithm for Ξ codes with dfree⩾5 is also introduced. Computer searches are performed to construct good Ξ and Ξf codes. For specified decoding complexities, a number of these new codes give better error performance than previously reported codes