  This paper investigates intelligent reflecting surface (IRS)-aided
multi-antenna wireless powered communications in a multi-link interference
channel, where multiple IRSs are deployed to enhance the downlink/uplink
communications between each pair of hybrid access point (HAP) and wireless
device. Our objective is to maximize the system sum throughput by optimizing
the allocation of communication resources. To attain this objective and
meanwhile balance the performance-cost tradeoff, we propose three transmission
schemes: the IRS-aided asynchronous (Asy) scheme, the IRS-aided time-division
multiple access (TDMA) scheme, and the IRS-aided synchronous (Syn) scheme. For
the resulting three non-convex design problems, we propose a general
algorithmic framework capable of suboptimally addressing all of them. Numerical
results show that our proposed IRS-aided schemes noticeably surpass their
counterparts without IRSs in both system sum throughput and total transmission
energy consumption at the HAPs. Moreover, although the IRS-aided Asy scheme
consistently achieves the highest sum throughput, the IRS-aided TDMA scheme is
more appealing in scenarios with substantial cross-link interference and
limited IRS elements, while the IRS-aided Syn scheme is preferable in low
cross-link interference scenarios.
