Secrecy rate for MISO rayleigh fading channels with relative distance of eavesdropper

In this letter, we extend the results of secure transmission with artificial noise over multiple-input single-output (MISO) wiretap channels. There is a case such that the transmitter knows the relative distance of the eavesdropper. That is, it knows the distance from itself to the eavesdropper divided by its distance to the legitimate receiver. The study found that when the transmitter utilizes information about the relative distance of the passive eavesdropper, the system can achieve a significant increase in its secrecy rate. This work may be useful evaluating a secure communication system in where a secure-zone is enforced and is accessible, exclusively, to the legitimate receiver.