In Fig. 2, the total transmit power in different schemes are
compared. The zero-forcing based scheme is adapted from
[4] [10], in which zero-forcing is applied to nullify SI and
MUI with the limited number of antennas at relays. Effective
in single-relay scenario, such a scheme fails to combat IRI,
resulting in higher transmit power at BS. The gap in power
consumption from the other two schemes broadens quickly as
the IRI strength GIRI increases, which indicates the necessity
of addressing IRI in a multiple-FDR-aided multiuser network.
For the conventional duality-based algorithm, after sufficient
iterations a feasible solution can be achieved but with innegligible
performance loss. In contrast, our proposed distributed
algorithm suppresses all types of interference jointly with
limited spatial degrees of freedom at relays, and achieves the
best performance after sufficient iterations, which is also the
optimum of centralized algorithm.