We investigate the scalability of a class of algorithms that exploit the dynamics of wireless fading channels to achieve secret communication in a large wireless network of n randomly located nodes. We describe a construction in which nodes transmit artificial noise to suppress eavesdroppers whose locations are unknown and ensure secrecy of messages transported across the network. Under a model in which eavesdroppers operate independently and under appropriate conditions on the achievable per-node throughput Ψ(n), we show that the network can tolerate Ω((1⁄√n(n))2c) eavesdroppers while ensuring that the aggregate rate at which eavesdroppers intercept packets goes to 0, where c is a constant such that 0 0. We also establish sufficient conditions on the number of eavesdroppers to achieve a non-zero throughput in our construction.
We investigate the scalability of a class of algorithms that exploit the dynamics of wireless fading channels to achieve secret communication in a large wireless network of n randomly located nodes. We describe a construction in which nodes transmit artificial noise to suppress eavesdroppers whose locations are unknown and ensure secrecy of messages transported across the network. Under a model in which eavesdroppers operate independently and under appropriate conditions on the achievable per-node throughput Ψ(n), we show that the network can tolerate Ω((1⁄√n(n))2c) eavesdroppers while ensuring that the aggregate rate at which eavesdroppers intercept packets goes to 0, where c is a constant such that 0 0. We also establish sufficient conditions on the number of eavesdroppers to achieve a non-zero throughput in our construction.
Since wireless channel is vulnerable to eavesdroppers, the secrecy during message delivery is a major concern in many applications such as commercial, governmental and military networks. This paper investigates information-theoretic secrecy in large-scale networks and studies how capacity is affected by the secrecy constraint where the locations and channel state information (CSI) of eavesdroppers are both unknown. We consider two scenarios: 1) non-colluding case where eavesdroppers can only decode messages individually; and 2) colluding case where eavesdroppers can collude to decode a message. For the non-colluding case, we show that the network secrecy capacity is not affected in order-sense by the presence of eavesdroppers. For the colluding case, the per-node secrecy capacity of Θ(1/√n) can be achieved when the eavesdropper density ψe(n) is O(n-β), for any constant β >; 0 and decreases monotonously as the density of eavesdroppers increases. The upper bounds on network secrecy capacity are derived for both cases and shown to be achievable by our scheme when ψe(n) = O(n-β) or ψe(n) = Ω(log α-2/α n), where α is the path loss gain. We show that there is a clear tradeoff between the security constraints and the achievable capacity.
This paper studies the achievable secure rate per source-destination pair in wireless networks. First, a path loss model is considered, where the legitimate and eavesdropper nodes are assumed to be placed according to Poisson point processes with intensities λ and λe, respectively. It is shown that, as long as λe/λ =o((logn)-2), almost all of the nodes achieve a perfectly secure rate of Ω(1/√n) for the extended and dense network models. Therefore, under these assumptions, securing the network does not entail a loss in the per-node throughput. The achievability argument is based on a novel multihop forwarding scheme where randomization is added in every hop to ensure maximal ambiguity at the eavesdropper(s). Second, an ergodic fading model withnsource-destination pairs and neeavesdroppers is considered. Employing the ergodic interference alignment scheme with an appropriate secrecy precoding, each user is shown to achieve a constant positive secret rate for sufficiently largen. Remarkably, the scheme does not require eavesdropper CSI (only the statistical knowledge is assumed) and the secure throughput per node increases as we add more legitimate users to the network in this setting. Finally, the effect of eavesdropper collusion on the performance of the proposed schemes is characterized.
This work studies the achievable secure rate per source-destination pair in wireless networks. First, a path loss model is considered, where the legitimate and eavesdropper nodes are assumed to be placed according to Poisson point processes with intensities λ and λe, respectively. It is shown that, as long as λe/λ=o((logn)−2), almost all of the nodes achieve a perfectly secure rate of Ω(n1) for the extended and dense network models. Therefore, under these assumptions, securing the network does not entail a loss in the per-node throughput. The achievability argument is based on a novel multi-hop forwarding scheme where randomization is added in every hop to ensure maximal ambiguity at the eavesdropper(s). Secondly, an ergodic fading model with n source-destination pairs and ne eavesdroppers is considered. Employing the ergodic interference alignment scheme with an appropriate secrecy pre-coding, each user is shown to achieve a constant positive secret rate for sufficiently large n. Remarkably, the scheme does not require eavesdropper CSI (only the statistical knowledge is assumed) and the secure throughput per node increases as we add more legitimate users to the network in this setting. Finally, the effect of eavesdropper collusion on the performance of the proposed schemes is characterized.
Artificial noise has been considered as an effective and efficient way to improve the secrecy of wireless communications. However, most existing papers have been focused on the analysis of a single communication link between a transmitter and a legitimate receiver with some eavesdroppers. In this paper, we investigate the impact of artificial noise to the secrecy of a large scale decentralized wireless network where channels are modeled as Rayleigh fading and locations of legitimate nodes and eavesdroppers follow Poisson point processes. To study network throughput versus system parameters, we derive the secrecy transmission capacity and show how it is related to the number of transmitting antennas and the power allocation ratio between data and artificial noise. Analytical results provide insights on how system parameters can be designed to improve secrecy transmission capacity of a wireless network.
The broadcast nature of the wireless medium makes the communication over this medium vulnerable to eavesdropping. This report considers the problem of secret communication between two nodes, over a fading wireless medium, in the presence of a passive eavesdropper. The assumption used is that the transmitter and its helpers (amplifying relays) have more antennas than the eavesdropper. The transmitter ensures secrecy of communication by utilizing some of the available power to produce ‘artificial noise’, such that only the eavesdropper’s channel is degraded. Two scenarios are considered, one where the transmitter has multiple transmit antennas, and the other where amplifying relays simulate the effect of multiple antennas. The channel state information (CSI) is assumed to be publicly known, and hence, the secrecy of communication is independent of the secrecy of CSI.
The secure transmission of information in wireless networks without knowledge of eavesdropper channels or locations is considered. Two key mechanisms are employed: artificial noise generation from system nodes other than the transmitter and receiver, and a form of multi-user diversity that allows message reception in the presence of the artificial noise. We determine the maximum number of independently-operating and uniformly distributed eavesdroppers that can be present while the desired secrecy is achieved with high probability in the limit of a large number of system nodes. While our main motivation is considering eavesdroppers of unknown location, we first consider the case where the path-loss is identical between all pairs of nodes. In this case, a number of eavesdroppers that is exponential in the number of systems nodes can be tolerated. In the case of uniformly distributed eavesdroppers of unknown location, any number of eavesdroppers whose growth is sub-linear in the number of system nodes can be tolerated. The proposed approach significantly outperforms a power control approach based on standard multi-user diversity.