SWIPT-Enabled MISO Ad Hoc Network Underlay RSMA-based System with IRS

In this paper, we propose a simultaneous wireless information and power transfer (SWIPT)-enabled ad hoc network underlay rate-splitting multiple access (RSMA)-based system with intelligent reflecting surface (IRS). Therein, a base station (BS) in a primary network uses RSMA to serve primary users (PUs), and secondary user (SU) pairs constitute an ad hoc network sharing the spectrum with the primary network. Both power splitting (PS)- and time splitting (TS)-based SWIPT protocols are used in the ad hoc network that allow the SU receivers to decode the information and harvest energy simultaneously. An IRS is deployed to further enhance the system performance. We formulate optimization problems that optimize the common data rate allocation and beamformers associated with the common and private messages of RSMA, the beamformers and the PS/TS factors in the ad hoc network, and reflection coefficients of the IRS to maximize the minimum rate of the PUs while satisfying the requirements of harvested energy and data rate of the SU pairs. The optimization problems are non-convex and challenging to be solved. We propose low complexity algorithms based on alternating descent techniques. Numerical results demonstrate the effectiveness and improvement of the proposed algorithms, especially when combined with the TS-based SWIPT.