Secure Multiuser Communications in Multiple Amplify-and-Forward Relay Networks

Abstract

Abstract-This paper proposes relay selection to increase the physical layer security in multiuser cooperative relay networks with multiple amplify-and-forward relays, in the presence of multiple eavesdroppers. To strengthen the network security against eavesdropping attack, we present three criteria to select the best relay and user pair. Specifically, criteria I and II study the received signal-to-noise ratio (SNR) at the receivers, and perform the selection by maximizing the SNR ratio of the user to the eavesdroppers. To this end, criterion I relies on both the main and eavesdropper links, while criterion II relies on the main links only. Criterion III is the standard max-min selection criterion, which maximizes the minimum of the dual-hop channel gains of main links. For the three selection criteria, we examine the system secrecy performance by deriving the analytical expressions for the secrecy outage probability. We also derive the asymptotic analysis for the secrecy outage probability with high main-to-eavesdropper ratio. From the asymptotic analysis, an interesting observation is reached: for each criterion, the system diversity order is equivalent to the number of relays regardless of the number of users and eavesdroppers.Index Terms-Multiuser communications, multi-relay cooperative networks, multiple eavesdroppers, physical layer security, secrecy outage probability.

Secure Multiple Amplify-and-Forward Relaying With Cochannel Interference

“…An eavesdropper, E, can overhear the message forwarded from relays, which indicates a great threat to the communication from S to D. Note that the network secrecy performance becomes worse if multiple eavesdroppers exist in the network, no matter whether the eavesdroppers decode the messages in a colluding or non-colluding manner [20]. However, the relay selection criteria and the secrecy performance analytical framework proposed in this work can be easily extended to the case of multiple eavesdroppers.…”

“…As such, it is not trivial to derive an exact analytical expression for the SOP, since γ D n and γ E n are correlated RVs. To deal with this issue, we note that the authors in [20] presented simplified expressions for γ D n and γ E n , by assuming large transmit power P . However, this is not applicable in practical scenarios, where the terminals are limited powered, e.g., mobile devices or sensor nodes.…”

“…It is worthwhile to note that the lower bound derived above can be used for the entire regime of transmit power, thus being more applicable than the method given by [20] for secrecy performance evaluation.…”

“…However, this probability is just a special case of the SOP, where the target secrecy data rate is set to zero. Furthermore, the authors in [20] investigated the PLS of multiuser multi-AF relay networks, and presented closedform expressions for the limiting behavior of SOP, assuming a large transmit power.…”

Network-coded primary-secondary cooperation in OFDM-based cognitive multicast networks

“…The case with direct links between the PT and its corresponding PR involves many complicated problems such as the maximum ratio combination of network-coded data and direct transmitted data and is beyond the focus of the paper. In addition, due to the long distance or the shielding effect caused by some barrier between each PT and its corresponding PR, the PR is not within the communication range of the PT, and thus, the assumption that there is no direct link between the source and destination is reasonable for some practical applications [33][34][35].…”