Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Free Distance Bounds for Protograph-Based Regular LDPC Convolutional
  Codes   In this paper asymptotic methods are used to form lower bounds on the free
distance to constraint length ratio of several ensembles of regular,
asymptotically good, protograph-based LDPC convolutional codes. In particular,
we show that the free distance to constraint length ratio of the regular LDPC
convolutional codes exceeds that of the minimum distance to block length ratio
of the corresponding LDPC block codes.

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The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas