Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bidirectional MMSE Algorithms for Interference Mitigation in CDMA
  Systems over Fast Fading Channels   This paper presents adaptive bidirectional minimum mean-square error (MMSE)
parameter estimation algorithms for fast-fading channels. The time correlation
between successive channel gains is exploited to improve the estimation and
tracking capabilities of adaptive algorithms and provide robustness against
time-varying channels. Bidirectional normalized least mean-square (NLMS) and
conjugate gradient (CG) algorithms are devised along with adaptive mixing
parameters that adjust to the time-varying channel correlation properties. An
analysis of the proposed algorithms is provided along with a discussion of
their performance advantages. Simulations for an application to interference
suppression in DS-CDMA systems show the advantages of the proposed algorithms.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: econ
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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: hep-ex
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The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph