Low Latency and Memory Efficient Viterbi Decoder Using Modified State-Mapping Method

Sang-Ho SEO
Hae-Wook CHOI
Sin-Chong PARK

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.4    pp.1413-1416
Publication Date: 2006/04/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.4.1413
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
Keyword: 
Viterbi decoder,  register exchange,  trace back,  latency,  resource usage,  

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Summary: 
In this paper, a new implementation of the Viterbi decoder is proposed. The Modified State-Mapping VD algorithm combines the TB algorithm with the RE algorithm. By updating the starting point of the state for each memory bank, and by using Trace Back and Trace Forward information, LIFO (Last Input First Output) operation can be eliminated, which reduces the latency of the TB algorithm and decreases the resource usage of the RE algorithm. When the memory unit is 3, the resource usage is 13184 bits and the latency is 54 clocks. The latency of the proposed algorithm is 25% smaller than the MRE algorithm and 50% smaller than the k-pointer even TB algorithm. In addition, resource usage is 50% smaller than the RE algorithm. The resource usage is a little larger than that of the MRE algorithm for the small value of k, but it becomes smaller after k is larger than 16.