  We consider a wiretap channel with an eavesdropper (Eve) and an honest but
curious relay (Ray). Ray and the destination (Bob) are full-duplex (FD)
devices. Since we aim at not revealing information on the secret message to the
relay, we consider the scaled compute-and-forward (SCF) where scaled lattice
coding is used in the transmission by both the source (Alice) and Bob in order
to allow Ray to decode only a linear combination of the two messages. At the
same time Ray transmits artificial noise (AN) to confuse Eve. When Ray relays
the decoded linear combination, Alice and Bob are transmitting AN against Eve.
This can be a 5G cellular communication scenario where a mobile terminal (MT)
aims at transmitting a secret message to a FD base station (BS), with the
assistance of a network FD relay. With respect to existing literature the
innovations of this paper are: a) Bob and Ray are FD devices; b) Alice, Ray and
Bob transmit also AN; and c) the channel to Eve is not known to Alice, Bob and
Ray. For this scenario we derive bounds on both the secrecy outage probability
under Rayleigh fading conditions of the channels to Eve, and the achievable
secrecy-outage rates.
