Date Added: Jan 2012
The secure transmission of information in wireless networks without knowledge of the eavesdroppers' locations is considered. Two key mechanisms are employed: artificial noise generation from system nodes other than the transmitter and receiver, and a form of multi-user diversity that allows message reception in the presence of the artificial noise. The authors consider the maximum number of independently-operating and uniformly distributed eavesdroppers that can be present while the desired secrecy is achieved with high probability in the limit of a large number of system nodes. While their main motivation is considering eavesdroppers of unknown location, they first consider the case where the path-loss is identical between all pairs of nodes.