In this paper, we consider the problem of secret communication through Rayleigh fading single-input multiple-output (SIMO) broadcast channel in the presence of an eavesdropper. At first, we define the ergodic secrecy capacity and find the optimal power allocation at the transmitter that achieves the secrecy capacity for the full channel state information (CSI) case, where transmitter has access to both the main channel and eavesdropper's channel gains, and for the case of only main channel CSI at the transmitter. Then, we define the secrecy capacity in case of open-loop transmission scheme and present the analytical expression for the lower bound of ergodic secrecy capacity. We also find the analytical expression for secure outage probability to study the secure outage performance of the proposed model.
In this paper, we consider the problem of secret communication through Rayleigh fading single-input multiple-output (SIMO) broadcast channel in the presence of an eavesdropper. At first, we define the ergodic secrecy capacity and find the optimal power allocation at the transmitter that achieves the secrecy capacity for the full channel state information (CSI) case, where transmitter has access to both the main channel and eavesdropper's channel gains, and for the case of only main channel CSI at the transmitter. Then, we define the secrecy capacity in case of open-loop transmission scheme and present the analytical expression for the lower bound of ergodic secrecy capacity. We also find the analytical expression for secure outage probability to study the secure outage performance of the proposed model.
Nakagami-m fading channel is chosen to analyze the secrecy capacity for fading channels since the Nakagami-m distribution can model fading conditions, which are more or less severe than that of Rayleigh and has the advantage of including Rayleigh as a special case. At first, secrecy capacity is defined in case of full channel state information (CSI) at the transmitter, where transmitter has access to both the main channel and eavesdropper channel gains. Secondly, secrecy capacity is defined with only main channel CSI at the transmitter. Then, optimal power allocation at the transmitter that achieves the secrecy capacity is derived for both the cases. Moreover, secrecy capacity is defined under open-loop transmission scheme, and the exact closed form analytical expression for the lower bound of ergodic secrecy capacity is derived for Nakagami-m fading single-input multiple-output (SIMO) channel. In addition, secrecy capacity is defined for the AWGN channel in order to realize the information-theoretic security of wireless channels with no fading. Finally, analytical expressions for the probability of non-zero secrecy capacity and secure outage probability are derived in order to investigate the secure outage performance of fading channels.
We consider a single-input multiple-output (SIMO) Rayleigh fading broadcast channel, where the transmitter sends some confidential information to one user which is a legitimate receiver in the presence of multiple eavesdroppers. The eavesdroppers are mutually independent and perfect secrecy is achieved when the transmitter and the legitimate receiver can communicate at some positive rate, while insuring that each eavesdropper gets zero bits of information. Here, we find the probability of non-zero secrecy mutual information and secure outage probability to investigate the outage behavior of proposed model. We also present a formulation of ergodic secrecy mutual information in the presence of multiple eavesdroppers.
We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. We first consider the full channel state information (CSI) case, where the transmitter has access to the channel gains of the legitimate receiver and the eavesdropper. The secrecy capacity under this full CSI assumption serves as an upper bound for the secrecy capacity when only the CSI of the legitimate receiver is known at the transmitter, which is characterized next. In each scenario, the perfect secrecy capacity is obtained along with the optimal power and rate allocation strategies. We then propose a low-complexity on/off power allocation strategy that achieves near-optimal performance with only the main channel CSI. More specifically, this scheme is shown to be asymptotically optimal as the average signal-to-noise ratio (SNR) goes to infinity, and interestingly, is shown to attain the secrecy capacity under the full CSI assumption. Overall, channel fading has a positive impact on the secrecy capacity and rate adaptation, based on the main channel CSI, is critical in facilitating secure communications over slow fading channels.
We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. We first consider the full Channel State Information (CSI) case, where the transmitter has access to the channel gains of the legitimate receiver and the eavesdropper. The secrecy capacity under this full CSI assumption serves as an upper bound for the secrecy capacity when only the CSI of the legitimate receiver is known at the transmitter, which is characterized next. In each scenario, the perfect secrecy capacity is obtained along with the optimal power and rate allocation strategies. We then propose a low-complexity on/off power allocation strategy that achieves near-optimal performance with only the main channel CSI. More specifically, this scheme is shown to be asymptotically optimal as the average SNR goes to infinity, and interestingly, is shown to attain the secrecy capacity under the full CSI assumption. Remarkably, our results reveal the positive impact of fading on the secrecy capacity and establish the critical role of rate adaptation, based on the main channel CSI, in facilitating secure communications over slow fading channels.
We consider the problem of secret communication over Nakagami-m fading multiple-input single-output (MISO) broadcast channel, where transmitter sends messages to the destination users following two different transmission protocols. In the first transmission protocol, transmitter sends a confidential message to user 1, and user 2 acts as an eavesdropper. In this protocol, at first, we define the ergodic secrecy capacity for the full channel state information (CSI) case and then we consider the case of only main channel CSI at the transmitter. Finally, we define the secrecy capacity in case of open-loop spatial multiplexing transmission scheme and present the analytical expression for the lower bound of ergodic secrecy capacity. In the second transmission protocol, we consider the transmission of two independent messages to user 1 and user 2 with information-theoretic secrecy, where each user would like to obtain its own confidential message in a reliable and safe manner. Under this communication scenario, an achievable secrecy capacity region is developed using secret dirty-paper coding scheme.
We consider the secure transmission of information over an ergodic fading channel in the presence of an eavesdropper. Our eavesdropper can be viewed as the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a system is characterized under the assumption of asymptotically long coherence intervals. We analyze the full Channel State Information (CSI) case, where the transmitter has access to the channel gains of the legitimate receiver and eavesdropper, and the main channel CSI scenario, where only the legitimate receiver channel gain is known at the transmitter. In each scenario, the secrecy capacity is obtained along with the optimal power and rate allocation strategies. We then propose a low-complexity on/off power allocation strategy that achieves near-optimal performance with only the main channel CSI. More specifically, this scheme is shown to be asymptotically optimal as the average SNR goes to infinity, and interestingly, is shown to attain the secrecy capacity under the full CSI assumption. Remarkably, our results reveal the positive impact of fading on the secrecy capacity and establish the critical role of rate adaptation, based on the main channel CSI, in facilitating secure communications over slow fading channels.