A Cooperative Spectrum Sensing Algorithm Based On Bayesian Compressed
Sensing
Rikang Zhou, Yuyan Zhang, Xuekang Sun, Caili Guo
School of Telecommunication Education
Beijing University of Posts and Telecommunications,
Beijing, 100876
e-mail: zhourikang@gmail.com
Abstract—Compressed sensing (CS) has been applicably used
in cognitive radio (CR) to sense wide-band spectrum, solving
the wide-band sensing rate restriction problem. For a CR
network which includes multiple nodes, it's considered that the
received signals is high correlated. So in this paper, we focus
on efficient compressed spectrum sensing reconstructions in
CR network, proposing a probabilistic model called
Cooperative Bayesian Compressed Spectrum Sensing (C-BCSS)
algorithm. In the algorithm, node samples locally and a
common sparse signal model is developed to the received
signals where correlation exists. And then C-BCSS
reconstruction is performed cooperatively at fusion center
utilizing the information from all nodes. We compared C-
BCSS with Multitask BCS and simulation results show that C-
BCSS outperforms in condition of severe under-sampling and
heavy noise.
Keywords-spectrum sensing, cognitive radio, Bayesian
compressed sensing, distributed network
I. INTRODUCTION
Cognitive radio [1] technology as a novel approach has
been proposed to improve the status of spectrum under-
utilization. Indeed, for the current static spectrum allocation
policy, some frequency bands have been utilized in an
inefficient way. Investigations show that some frequency
bands are fully occupied, while some others turn out to be
idle at most of the time [2]. The idle spectrum which has
been called spectrum hole generally is a band of frequencies
which is assigned to a licensed primary user (PU), but not
occupied at a particular time and specific geographic location.
CR network allows secondary users (SUs), who actually are
not authorized to utilize the frequency band,
opportunistically to access spectrum to use spectrum source
with principle of no harm to PUs. This sharing strategy
allows SUs to exist heterogeneously with PUs to utilize
spectrum efficiently, and nowadays it attracts great interests
of applying it in fifth generation of cellular wireless (5G)
technology [3].
Primarily, before being free to access spectrum holes for
SUs, spectrum sensing should be performed intelligently and
instantaneously to detect whether the spectrum is occupied
by PUs. However spectrum sensing is a challenge in the case
of sensing a wide-band spectrum. Conventional methods are
inefficient and impractical in terms of sensing rate and
accuracy. A general way like using analog-to-digital
converter (ADC) will suffer a severe hardware restriction
because of high sampling rate. To this problem, CS [4] is
adopted as an effective solution utilizing its merit that a
small collection of measurements of a sparse signal contains
enough information to reconstruct the underlying signal
perfectly, which means wide-band spectrum can be sensed at
a low rate. Some wide-band spectrum sensing schemes based
on CS methodology are introduced in a non-cooperation
scenario [5], using orthogonal matching pursuit (OMP)
algorithm and basis pursuit (BP) algorithm. Bayesian
compressed sensing (BCS) [6] is another efficient
reconstruction algorithm derived from the technology in
Relevance Vector Machine (RVM) [7]. In BCS model, prior
information is adopted to the signal in the Bayesian
perspective. It turns out that BCS has sparser solution and
outperformance of robustness to noise.
In fact, considering in a network, all SUs receive signals
and it is rich of interrelated information in space and time or
redundant structures about the received signals. The signals
can be reconstructed jointly and cooperatively. In the
literature of CS, this has been previously studied in the field
of distributed compressed sensing (DCS) [8] and
simultaneous sparse approximation [9]. Joint sparsity model
(JSM) has been proposed to model multi-signal ensembles
and applied in joint spares recovery algorithms. In paper [10],
Multitask BCS is proposed and shows a good performance,
where all node use a shared prior to help every node's
construction.
In this paper, to utilize the interrelated information and
promote the performance further, we propose an algorithm
called Cooperative Bayesian Compressed Spectrum Sensing
to offer an efficient cooperative reconstruction method over
the network. In the algorithm, we develop a common sparse
signal model to the underlying spectrum signals. And then a
joint recovery proceeds via the regression of joint BCS we
obtained. Rather than a shared prior, a shared sparse signal
model leads to promotions of C-BCSS compared with
Multitask BCS.
The reminder of this paper is organized as follow. In
section II, we describe the signal model and basic principle
briefly and lead to the problem statement. In section III, we
go into details about C-BCSS. Then we talk about simulation
results in section IV. Conclusion is drawn in section V.
II. SYSTEM MODEL AND PROBLEM FORMULATION
Assume that a wide-band spectrum is shared by SUs and
PUs in a CR network, and the spectrum is sensed by L SUs.
We adopt a slotted frequency segmentation structure to the
wide-band spectrum and divide the spectrum into N non-
overlapping sub-channels equably. We assume that K (K <<
N) stochastic sub-channels is occupied in a SU's detection
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2017 3rd IEEE International Conference on Computer and Communications
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