Exploiting Fountain Codes for Secure Wireless Delivery

In this letter, a secure delivery scheme that exploits fountain codes is analyzed. For fountain-coded transmission, the receivers have to obtain a sufficient number of fountain packets to recover the original data. Secure delivery can be achieved if the legitimate user receives enough fountain packets first. For this purpose, we utilize the independent channel fading of different users to ensure a higher packet reception rate at the destination. The channel fading is competent if the destination is known to have a better average channel condition than that of the eavesdropper; otherwise, transmit power control relative to the destination channel is employed. Numerical results show that the intercept probability is reduced to zero exponentially as the number of source packets increases. Moreover, due to the ordinary fountain-coded transmission, the achievable data rate of the delivery depends only on the source-destination channel capacity rather than the system secrecy capacity.