Secure Cooperative Transmission in Rateless-Coded Environment Using TAS and Artificial Noise

In this paper, we analyse a secure transmission scheme using rateless codes (RC) in a delay constrained system. By using RC, secrecy is achieved if the legitimate receiver can accumulate required number of packets before an eavesdropper does. To achieve this, we employ transmit antenna selection (TAS) at the base station to improve the main channel and, artificial noise (AN) is generated by the use of a cooperative jammer to degrade the eavesdropper's channel. Quality of violation probability (QVP) which consists of both the delay violation probability and the intercept probability is used as a performance metric. A closed-form expression for QVP is derived. We show that using TAS for reducing QVP is effective only at lower signal to noise ratio (SNR). We also observe that on increasing number of antennas at the source ($N_{A}$) while using TAS along with AN, QVP decreases for delay sensitive services, whereas, in case of delay tolerant applications, increasing $N_{A}$ is effective at low SNR.