Abstract This paper analyzes the achievable secrecy rate in a millimeter wave (mmWave) ad hoc network with multi‐array antenna transmission in the presence of non‐colluding and colluding eavesdroppers. By exploiting the tools of stochastic geometry, the average achievable secrecy rate is derived, taking into consideration the impact of blockages, directional beamforming, and Nakagami‐ m fading. Moreover, a simple yet effective artificial noise transmission (Tx‐AN) technique is applied at the transmitting nodes to enhance the secrecy performance while the channel state information at the desired transmitter is unknown. Numerical and simulation results are presented for the average achievable secrecy rate in the mmWave ad hoc network without and with the Tx‐AN technique. For example, at the high transmit power (>20 dBm), the average achievable secrecy rate with the Tx‐AN technique is up to three times higher than that obtained when the Tx‐AN technique is not used. Furthermore, the results demonstrate the secrecy robustness of the Tx‐AN technique against increasing eavesdroppers' intensity. Finally, the proper power allocation between the message and AN signals that maximizes the average achievable secrecy rate is computed.
Abstract This paper analyzes the achievable secrecy rate in a millimeter wave (mmWave) ad hoc network with multi‐array antenna transmission in the presence of non‐colluding and colluding eavesdroppers. By exploiting the tools of stochastic geometry, the average achievable secrecy rate is derived, taking into consideration the impact of blockages, directional beamforming, and Nakagami‐ m fading. Moreover, a simple yet effective artificial noise transmission (Tx‐AN) technique is applied at the transmitting nodes to enhance the secrecy performance while the channel state information at the desired transmitter is unknown. Numerical and simulation results are presented for the average achievable secrecy rate in the mmWave ad hoc network without and with the Tx‐AN technique. For example, at the high transmit power (>20 dBm), the average achievable secrecy rate with the Tx‐AN technique is up to three times higher than that obtained when the Tx‐AN technique is not used. Furthermore, the results demonstrate the secrecy robustness of the Tx‐AN technique against increasing eavesdroppers' intensity. Finally, the proper power allocation between the message and AN signals that maximizes the average achievable secrecy rate is computed.
Wireless networks with directional antennas, like millimeter wave (mmWave) networks, have enhanced security. For a large scale mmWave ad hoc network in which eavesdroppers are randomly located, however, eavesdroppers can still intercept the confidential messages, since they may reside in the signal beam. This paper explores the potential of physical layer security in the mmWave ad hoc networks. Specifically, we characterize the impact of mmWave channel characteristics and large antenna arrays on the secrecy performance. We also characterize the impact of artificial noise in this networks. Our results reveal that in the low transmit power regime, the use of low mmWave frequency achieves better secrecy performance, when increasing transmit power, a transition from low mmWave frequency to high mmWave frequency is demanded for obtaining more secrecy rate. Eavesdroppers can intercept more information by using wide beam pattern. Furthermore, the use of artificial noise may be unable to enhance the secrecy rate for the case of low node density.
Abstract—We study physical-layer security in wireless ad hoc networks and investigate two types of multi-antenna transmission schemes for providing secrecy enhancements. To establish secure transmission against malicious eavesdroppers, we consider the generation of artificial noise with either sectoring or beamform-ing. For both approaches, we provide a statistical characterization and tradeoff analysis of the outage performance of the legitimate communication and the eavesdropping links. We then investi-gate the networkwide secrecy throughput performance of both schemes in terms of the secrecy transmission capacity, and study the optimal power allocation between the information signal and the artificial noise. Our analysis indicates that, under transmit power optimization, the beamforming scheme outperforms the sectoring scheme, except for the case where the number of transmit antennas are sufficiently large. Our study also reveals some interesting differences between the optimal power allocation for the sectoring and beamforming schemes. Index Terms—Physical-layer security, ad hoc networks, multi-antenna transmission, artificial noise, power allocation, outage probability, throughput optimization. I.
We study physical-layer security in wireless ad hoc networks and investigate two types of multi-antenna transmission schemes for providing secrecy enhancements. To establish secure transmission against malicious eavesdroppers, we consider the generation of artificial noise with either sectoring or beamforming. For both approaches, we provide a statistical characterization and tradeoff analysis of the outage performance of the legitimate communication and the eavesdropping links. We then investigate the network-wide secrecy throughput performance of both schemes in terms of the secrecy transmission capacity, and study the optimal power allocation between the information signal and the artificial noise. Our analysis indicates that, under transmit power optimization, the beamforming scheme outperforms the sectoring scheme, except for the case where the number of transmit antennas are sufficiently large. Our study also reveals some interesting differences between the optimal power allocation for the sectoring and beamforming schemes.
By considering millimetre wave (mmWave) transmission as an effective solution for the fifth‐generation (5G) wireless communication systems, the authors propose a new optimal power allocation (OPA) scheme to maximise the instantaneous secrecy rate of a cooperative wireless network. The communication network under study is comprised of a multiple‐antennas source, a multiple‐antennas destination, a single antenna untrusted relay and single antenna passive eavesdroppers (Eves). To prevent the untrusted relay and passive Eves from overhearing the source message, a new secure transmission scheme is proposed. Based on this scheme, the destination sends an artificial noise (AN) towards the untrusted relay, and concurrently, the source is forced to dedicate part of its power to transmit AN to keep the information confidential from the Eves. For such a communication network, two cases of non‐colluding Eves (NCE) and colluding Eves (CE) are taken into account. Based on the proposed OPA, a novel closed‐form expression is presented for the ergodic secrecy rate (ESR) performance over mmWave channels. Next, the authors derive the high signal‐to‐noise ratio slope and power offset of the ESR to evaluate the effects of network parameters on the ESR performance. Numerical examples depict that the proposed optimised systems for both NCE and CE present superior ESR compared to other transmission policies.
Millimeter-wave (mmWave) communication is one of the key enabling technologies for fifth generation (5G) mobile networks. In this paper, we study the problem of secure communication in a mmWave wiretap network, where directional beamforming and link blockages are taken into account. For the secure transmission in the presence of spatially random eavesdroppers, an adaptive transmission scheme is adopted, for which sector secrecy guard zone and artificial noise (AN) are employed to enhance secrecy performance. When there exists no eavesdroppers within the sector secrecy guard zone, the transmitter only transmits information-bearing signal, and, conversely, AN along with information-bearing signal are transmitted. The closed-form expressions for secrecy outage probability (SOP), connection outage probability (COP) and secrecy throughput are derived under stochastic geometry. Then, we evaluate the effect of the sector secrecy guard zone and AN on the secrecy performance. Our results reveal that the application of the sector secrecy guard zone and AN can significantly improve the security of the system, and blockages also can be utilized to improve secrecy performance. An easy choice of transmit power and power allocation factor is provided for achieving higher secrecy throughput. Furthermore, increasing the density of eavesdroppers not always deteriorates the secrecy performance due to the use of the sector secrecy guard zone and AN.
In this paper, we study the secure multi-antenna transmission with artificial noise (AN) under slow fading channels coexisting with randomly located eavesdroppers. We provide a comprehensive secrecy performance analysis and system design/optimization under a stochastic geometry framework. Specifically, we first evaluate the secrecy outage performance, and derive a closed-form expression for the optimal power allocation ratio of the information signal power to the total transmit power that minimizes the secrecy outage probability (SOP). Subject to a SOP constraint, we then propose a dynamic parameter transmission scheme (DPTS) and a static parameter transmission scheme (SPTS) to maximize secrecy throughput, and provide explicit solutions on the optimal transmission parameters, including the wiretap code rates, the on-off transmission threshold and the power allocation ratio. Our results give new insight into secure transmission designs. For example, secrecy rate is a concave function of the power allocation ratio in DPTS, and AN plays a significant role under SOP constraints and in dense eavesdropper scenarios. In SPTS, transmission probability is a concave function of the power allocation ratio, and secrecy throughput is a quasi-concave function of the secrecy rate. Numerical results are demonstrated to validate our theoretical analysis.