PROJECT TITLE :

Near-Optimal Modulo-and-Forward Scheme for the Untrusted Relay Channel

ABSTRACT:

This paper studies an untrusted relay channel, in that the destination sends artificial noise simultaneously with the supply sending a message to the relay, in order to protect the source’s confidential message. The traditional amplify-and-forward (AF) scheme shows poor performance in this situation as a result of of the interference power dilemma. Providing better security by using stronger artificial noise can consume additional power of the relay, impairing the confidential message’s transmission. To solve this problem, this paper proposes a modulo-and-forward (MF) operation at the relay with nested lattice encoding at the source. For the proposed MF theme with full channel state info at the transmitter (CSIT), theoretical analysis shows that the MF theme approaches the secrecy capacity at intervals one/a pair of bit for all channel realizations, and, hence, achieves full generalized security degrees of freedom (G-SDoF). In contrast, the AF theme can only achieve a little fraction of the G-SDoF. For the MF theme while not CSIT, the full outage event, outlined as either association outage or secrecy outage, is introduced. Based on this total outage definition, analysis shows that the proposed MF theme achieves the total generalized secure diversity gain (G-SDG) of order one. On the other hand, the AF theme will achieve a G-SDG of solely one/a pair of at most.