Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Random Matrix Approach to Wide Band Spectrum Sensing: Unknown Noise
  Variance Case   In this paper three different scenarios in wide band spectrum sensing have
been studied. While the signal and noise statistics are supposed to be
unspecified, random matrixes have been utilized in order to estimate the noise
variance. These scenarios are: 1- Number of subbands is specified and there is
enough information regarding being used or being unused for each of them. 2-
Number of subbands is known but there is no information about usage
distribution among them. 3- Number of subbands is unknown. Simulation results
showed the superior performance of the proposed scheme. Regarding the number of
samples, the proposed method requires less number of samples compared to the
cyclo-stationary spectrum sensing algorithms and more samples compared to the
energy detection based methods. But, regarding the detection probability, the
proposed method is superior compared to both other spectrum sensing methods.

34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio