  This paper considers the transmitter design for wireless information and
energy transfer (WIET) in a multiple-input single-output (MISO) interference
channel (IFC). The design problem is to maximize the system throughput (i.e.,
the weighted sum rate) subject to individual energy harvesting constraints and
power constraints. Different from the conventional IFCs without energy
harvesting, the cross-link signals in the considered scenario play two opposite
roles in information detection (ID) and energy harvesting (EH). It is observed
that the ideal scheme, where the receivers can simultaneously perform ID and EH
from the received signal, may not always achieve the best tradeoff between
information transfer and energy harvesting, but simple practical schemes based
on time splitting may perform better. We therefore propose two practical time
splitting schemes, namely time division mode switching (TDMS) and time division
multiple access (TDMA), in addition to a power splitting (PS) scheme which
separates the received signal into two parts for ID and EH, respectively. In
the two-user scenario, we show that beamforming is optimal to all the schemes.
Moreover, the design problems associated with the TDMS and TDMA schemes admit
semi-analytical solutions. In the general K-user scenario, a successive convex
approximation method is proposed to handle the WIET problems associated with
the ideal scheme and the PS scheme, which are known to be NP-hard in general.
The K-user TDMS and TDMA schemes are shown efficiently solvable as convex
problems. Simulation results show that stronger cross-link channel powers
actually improve the information sum rate under energy harvesting constraints.
Moreover, none of the schemes under consideration can dominate another in terms
of the sum rate performance.
