Page 195 - Proceedings of the 2017 ITU Kaleidoscope

EXPLOITING MULTI-RADIO COOPERATION IN HETEROGENEOUS WIRELESS
NETWORKS FOR ABSOLUTE SECURITY AGAINST EAVESDROPPING

Ming Sun, Yulong Zou*, Mujun Qian, Jia Zhu, and Quanquan Wang

School of Telecomm. & Inform. Eng., Nanjing Univ. of Posts & Telecomm., Nanjing, P. R. China
*Corresponding author (email: yulong.zou@njupt.edu.cn)

ABSTRACT confidentiality is achieved.
In this paper, we consider a heterogeneous wireless com- At present, cooperative physical-layer security has attracted
munication scenario, which is comprised of a source (S) much attention of researchers, which is capable of enhancing
and a destination (D) in the presence of an eavesdropper the secrecy performance in wireless fading environments. In
(E), each equipped with multiple heterogeneous radio access [3], Lu investigated opportunistic relay and jammer coop-
interfaces. In order to enhance the transmission security eration in multiple-input multiple-output buffer-aided relay
against eavesdropping, we propose a multi-radio coopera- networks in which several relays are selected to protect the
tion (MRC) scheme, where the multiple radio interfaces at transmission of legitimate users and other relays are used to
S are simultaneously utilized to transmit a source signal to act as jammers to interfere the eavesdroppers. In [4], the au-
D along with a weight design. For the convenience of per- thors proposed relay selection for protecting the physical lay-
formance comparisons, the conventional multi-radio switch er security of wireless transmissions from secondary trans-
(MRS) scheme is also considered as a benchmark scheme, mitter to secondary destination against eavesdroppers in a
in which only the single “best” radio interface is selected cognitive radio network. In [5], Zou studied a source coop-
at S to transmit the source signal. We evaluate the secrecy eration aided opportunistic jamming scheme for enhancing
capacity and intercept probability (IP) of conventional MRS the secrecy performance of wireless communication against
and proposed MRC schemes over Rayleigh fading channels. eavesdropping for spectrum sharing systems. The author al-
It is proved that the proposed MRC scheme can achieve an so derived the closed-form intercept probability (IP) expres-
absolute security with zero IP, which is further validated sion for the proposed opportunistic jamming scheme over
through Monte-Carlo simulations. Numerical results show Rayleigh fading channels. It was shown that the IP perfor-
that the proposed MRC scheme performs better than conven- mance of spectrum sharing systems is improved significantly
tional MRS scheme in terms of their secrecy capacity and by exploiting opportunistic jamming.
IP. With the continuously increasing requirements of wireless
network performance, researchers focus their attention on the
Keywords— Heterogeneous wireless communication, multi-
study of multi-radio cooperation (MRC) [6]-[8], for hetero-
radio cooperation, physical layer security, absolute security
geneous wireless networks. The existing MRC technology
is mainly used for the integration of heterogeneous wireless
1. INTRODUCTION networks to reduce the multi-radio switch delay, expand the
coverage of wireless network, improve channel capacity and
Nowadays, mobile communication systems have evolved to a reduce energy consumption. To the best of our knowledge,
heterogeneous wireless network with the coexistence of mul- less attention has been paid to employing MRC to improve
tiple radio access technologies for meeting the demand of physical layer security in heterogeneous wireless network-
different wireless terminals. Due to the vulnerability of het- s. Motivated by the above observation, we explore the use
erogeneous wireless networks, there are various kinds of se- of MRC technology to defend against eavesdropping in het-
curity threats [1], and the wiretap attack is an important part erogeneous wireless networks. We propose a MRC scheme,
of them. With the rapid development of quantum comput- where the multiple radio interfaces at S are simultaneously u-
ers, the traditional secret key encryption is very difficult to tilized to transmit a source signal to D along with an optimal
completely prevent wiretap attacks, because eavesdropper- weight design. For convenience of performance comparison-
s can decrypt the secret key with powerful computing. To s, the conventional multi-radio switch (MRS) scheme is also
is end, researchers devote to exploring physical layer secu- considered as a benchmark, in which only the single “best”
rity against eavesdroppers by making full use of the physi- radio interface is selected at source S to transmit the source
cal characteristics of wireless channels. In [2], the secrecy signal. We evaluate the secrecy capacity and IP of conven-
capacity, defined as the difference between the capacity of tional MRS and proposed MRC schemes over Rayleigh fad-
main channel and that of wiretap channel, was presented to ing channels. It is proved that the proposed MRC scheme can
characterize the secrecy performance of wireless communi- achieve an absolute security with zero IP, which is further
cation. If the secrecy capacity is always positive, absolute validated through Monte-Carlo simulations. Numerical re-

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