642 research outputs found
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Cooperative Transmission Protocols with High Spectral Efficiency and High Diversity Order Using Multiuser Detection and Network Coding
Cooperative transmission is an emerging communication technique that takes
advantages of the broadcast nature of wireless channels. However, due to low
spectral efficiency and the requirement of orthogonal channels, its potential
for use in future wireless networks is limited. In this paper, by making use of
multiuser detection (MUD) and network coding, cooperative transmission
protocols with high spectral efficiency, diversity order, and coding gain are
developed. Compared with the traditional cooperative transmission protocols
with single-user detection, in which the diversity gain is only for one source
user, the proposed MUD cooperative transmission protocols have the merits that
the improvement of one user's link can also benefit the other users. In
addition, using MUD at the relay provides an environment in which network
coding can be employed. The coding gain and high diversity order can be
obtained by fully utilizing the link between the relay and the destination.
From the analysis and simulation results, it is seen that the proposed
protocols achieve higher diversity gain, better asymptotic efficiency, and
lower bit error rate, compared to traditional MUD and to existing cooperative
transmission protocols.Comment: to appear, in the proceedings of IEEE International Conference on
Communications, Glasgow, Scotland, 24-28 June 200
Performance Analysis and Resource Allocation in MIMO-OFDM Systems
The paper deals with the analysis of the vital performance plot of SNR and BER in MIMO systems. The importance of the diversity orders and the variation of the SNR-BER plot with respect to it is also studied using the simulation outputs. The three types of fading channels are also analysed. It is also seen that the presence of diversity and other schemes like Maximal Ratio Combining, selection combining, alamouti scheme increases the overall efficiency. The importance of the optimisation techniques and the superiority of the Monte Carlo optimization to the theoretical system without optimisation is also clearly visualised. The paper also deals with resource allocation in MIMO-OFDM systems. The advantage of the constant envelope OFDM over OFDM is achieved. Also the power allocation using water-filling algorithm and bandwidth-power product minimisation is compared using the obtained results
Secrecy Enhancement of Multiuser MISO Networks Using OSTBC and Artificial Noise
In this paper, we propose a novel physical layer
strategy to improve the secrecy performance of multiuser
multiple-input single-output networks. In this strategy, orthogonal
space-time block code (OSTBC) is employed at an AAantenna
base station (BS) and artificial noise (AN) is employed
at an AJ-antenna cooperative relay to enhance the security
level of the network. Moreover, two opportunistic scheduling
schemes, namely, selection combining (SC) and scan-and-wait
combining (SWC), are leveraged to select one legitimate user
for data transmission. To evaluate the secrecy performance of
the proposed OSTBC-SC-AN and OSTBC-SWC-AN schemes, we
derive new exact closed-form expressions for the secrecy outage
probability and the effective secrecy throughput. Using numerical
results, we show that the OSTBC-SWC-AN scheme outperforms
the OSTBC-SC-AN scheme when the switching threshold is
carefully chosen. We also show that increasing AA brings down
the secrecy performance in the presence of a high switching
threshold.ARC Discovery Projects Grant DP150103905
Secure Multiuser Communications in Wireless Sensor Networks with TAS and Cooperative Jamming
In this paper, we investigate the secure transmission in wireless sensor networks (WSNs) consisting of one multiple-antenna base station (BS), multiple single-antenna legitimate users, one single-antenna eavesdropper and one multiple-antenna cooperative jammer. In an effort to reduce the scheduling complexity and extend the battery lifetime of the sensor nodes, the switch-and-stay combining (SSC) scheduling scheme is exploited over the sensor nodes. Meanwhile, transmit antenna selection (TAS) is employed at the BS and cooperative jamming (CJ) is adopted at the jammer node, aiming at achieving a satisfactory secrecy performance. Moreover, depending on whether the jammer node has the global channel state information (CSI) of both the legitimate channel and the eavesdropper's channel, it explores a zero-forcing beamforming (ZFB) scheme or a null-space artificial noise (NAN) scheme to confound the eavesdropper while avoiding the interference to the legitimate user. Building on this, we propose two novel hybrid secure transmission schemes, termed TAS-SSC-ZFB and TAS-SSC-NAN, for WSNs. We then derive the exact closed-form expressions for the secrecy outage probability and the effective secrecy throughput of both schemes to characterize the secrecy performance. Using these closed-form expressions, we further determine the optimal switching threshold and obtain the optimal power allocation factor between the BS and jammer node for both schemes to minimize the secrecy outage probability, while the optimal secrecy rate is decided to maximize the effective secrecy throughput for both schemes. Numerical results are provided to verify the theoretical analysis and illustrate the impact of key system parameters on the secrecy performance.This work was supported by the National Science Foundation of China (No. 61501507), and the Jiangsu Provincial Natural Science Foundation of China (No. BK20150719). The work of Nan Yang is supported by the Australian Research Council Discovery Project (DP150103905)
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