This interference cannot be mitigated in the same
fashion as time-domain SI cancellation, since the transmitted
signal of each FDR is only known to itself. Among existing
research articles on FDR-aided cellular networks, [19] studies
resource allocation in an MIMO-FDR-aided OFDMA system,
where different end-to-end links are isolated via orthogonal
frequency allocation. This scheme avoids IRI and MUI, but the
gains from frequency reuse among geographically distributed
relays are lost. In [22] [23] [24], differentMIMO beamforming
schemes are proposed to suppress SI and MUI in single-FDR
systems. When these schemes are extended to practical multi-
FDR multi-user networks, severe performance loss may occur
because IRI is not considered. To the authors’ knowledge, an
efficient scheme for the suppression of IRI, SI and MUI in the
practical multi-FDR multi-user networks is still absent in the literature, thereby motivating the study of this work.