Security-Reliability Tradeoff Analysis for Artificial Noise Aided MISO Transmission System

Abstract

This paper studies the secure transmission problem of the artificial noise (AN) aided multiple-input single-output (MISO) system. Considering a practical assumption of worst-case scenario where the eavesdropper is passive and the noise at eavesdropper is arbitrarily small. The transmitter simultaneously transmits information-bearing signals and AN to the desired receiver and eavesdropper by multiple antennas. In this system, the exact closed-form expressions of outage probability (OP) and intercept probability (IP) which represent system reliability and security respectively are derived and the correctness of the derivation is proved by simulation. Next, the paper provides the security–reliability tradeoff (SRT) analysis of the system. It is found that the optimal power allocation between the information-bearing signal and AN to maximize SRT is different for different number of transmission antennas. Then, the SRT performance of the system is analyzed from the aspect of number of transmission antennas and signal-noise ratio (SNR) of the system under the condition of the optimal power allocation. It shows that the SRT performance can be better with the increasing number of the transmission antennas, which means a more secure and reliable communication transmission can be achieved. SRT will not keep enhancing when SNR reach a certain value which can provide valuable reference for setting the transmission power to avoid the waste of power.