Date Added: Sep 2012
The authors study the secure Degrees of Freedom (DoF) of one-hop wireless networks by considering four fundamental wireless network structures: Gaussian wiretap channel, Gaussian broadcast channel with confidential messages, Gaussian interference channel with confidential messages, and Gaussian multiple access wiretap channel. The secrecy capacity of the canonical Gaussian wiretap channel does not scale with the transmit power, and hence, the secure DoF of the Gaussian wiretap channel with no helpers is zero. It has been known that a strictly positive secure DoF. Can be obtained in the Gaussian wiretap channel by using a helper which sends structured cooperative signals. They show that the exact secure d.o.f. of the Gaussian wiretap channel with a helper is 1/2 .