  The recent attempts to realize full-duplex (FD) communications in millimeter
wave (mmWave) systems have garnered a significant amount of interest for its
potential. In this paper, we present a cost-efficient design of mmWave FD
systems, where the system dynamically reduces the RF beam codebook in a
computationally efficient manner, so that it is comprised of the RF beams that
will prevent the Rx receive chain from saturating due to the self-interference
(SI). The analog beamformer will suppress the SI to the level that the residual
SI can be completely removed with digital SI cancellation, allowing the digital
beamformer to concentrate on the desired channel, free of the SI. To reduce the
computation required for the proposed method, we propose two sufficient
conditions that prevent the Rx side saturations, which are practically tight.
Through performance valuations conducted in realistically modeled mmWave FD
scenarios, we demonstrate that the proposed design achieves comparable
performance with the ideal FD and other benchmarks with significantly lower
costs.
