  In this paper, we investigate the power efficient resource allocation
algorithm design for secure multiuser wireless communication systems employing
a full-duplex (FD) base station (BS) for serving multiple half-duplex (HD)
downlink (DL) and uplink (UL) users simultaneously. We propose a
multi-objective optimization framework to study two conflicting yet desirable
design objectives, i.e., total DL transmit power minimization and total UL
transmit power minimization. To this end, the weighed Tchebycheff method is
adopted to formulate the resource allocation algorithm design as a
multi-objective optimization problem (MOOP). The considered MOOP takes into
account the quality-of-service (QoS) requirements of all legitimate users for
guaranteeing secure DL and UL transmission in the presence of potential
eavesdroppers. Thereby, secure UL transmission is enabled by the FD BS and
would not be possible with an HD BS. The imperfectness of the channel state
information of the eavesdropping channels and the inter-user interference
channels is incorporated for robust resource allocation algorithm design.
Although the considered MOOP is non-convex, we solve it optimally by
semidefinite programming (SDP) relaxation. Simulation results not only unveil
the trade-off between the total DL transmit power and the total UL transmit
power, but also confirm the robustness of the proposed algorithm against
potential eavesdroppers.
