Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Medium Access over Time-varying Channels with Limited Sensing Cost   This paper has been withdrawn because of some paper issues. Recent studies on
MAC scheduling have shown that carrier sense multiple access (CSMA) can be
controlled to be achieve optimality in terms of throughput or utility. These
results imply that just a simple MAC algorithm without message passing is
possible to achieve high performance guarantee. However, such studies are
conducted only on the assumption that channel conditions are static. Noting
that the main drive for achieving optimality in optimal CSMA is to let it run a
good schedule for some time, formally referred to as the mixing time, it is
under-explored how such optimal CSMA performs for time-varying channel
conditions. In this paper, under the practical constraint of restricted
back-off rates (i.e., limited sensing speed), we consider two versions of
CSMAs: (i) channel-unaware CSMA (U-CSMA) and (ii) channel-aware CSMA (A-CSMA),
each of which is characterized as its ability of tracking channel conditions.
We first show that for fast channel variations, A-CSMA achieves almost zero
throughput, implying that incomplete tracking of channel conditions may
seriously degrade performance, whereas U-CSMA, accessing the media without
explicit consideration of channel conditions, has positive worst-case guarantee
in throughput, where the ratio of guarantee depends on network topology. On the
other hand, for slow channel variations, we prove that A-CSMA is
throughput-optimal for any network topology. Our results provide the precise
trade-off between sensing costs and performances of CSMA algorithms, which
guides a robust design on MAC scheduling under highly time-varying scenarios.

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The categories of this paper are: stat
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math