  This paper considers intelligent reflecting surface (IRS)-aided simultaneous
wireless information and power transfer (SWIPT) in a multi-user multiple-input
single-output (MISO) interference channel (IFC), where multiple transmitters
(Txs) serve their corresponding receivers (Rxs) in a shared spectrum with the
aid of IRSs. Our goal is to maximize the sum rate of the Rxs by jointly
optimizing the transmit covariance matrices at the Txs, the phase shifts at the
IRSs, and the resource allocation subject to the individual energy harvesting
(EH) constraints at the Rxs. Towards this goal and based on the well-known
power splitting (PS) and time switching (TS) receiver structures, we consider
three practical transmission schemes, namely the IRS-aided hybrid TS-PS scheme,
the IRS-aided time-division multiple access (TDMA) scheme, and the IRS-aided
TDMA-D scheme. The latter two schemes differ in whether the Txs employ
deterministic energy signals known to all the Rxs. Despite the non-convexity of
the three optimization problems corresponding to the three transmission
schemes, we develop computationally efficient algorithms to address them
suboptimally, respectively, by capitalizing on the techniques of alternating
optimization (AO) and successive convex approximation (SCA). Moreover, we
conceive feasibility checking methods for these problems, based on which the
initial points for the proposed algorithms are constructed. Simulation results
demonstrate that our proposed IRS-aided schemes significantly outperform their
counterparts without IRSs in terms of sum rate and maximum EH requirements that
can be satisfied under various setups. In addition, the IRS-aided hybrid TS-PS
scheme generally achieves the best sum rate performance among the three
proposed IRS-aided schemes, and if not, increasing the number of IRS elements
can always accomplish it.
