Concepts de base
The core message of this paper is to propose a novel system that incorporates a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) with simultaneous wireless information and power transfer (SWIPT) using rate splitting multiple access (RSMA) to optimize both the sum rate of information decoding receivers (IDRs) and the total harvested energy at energy harvesting receivers (EHRs).
Résumé
The paper presents a downlink STAR-RIS-assisted multi-user SWIPT system with RSMA. The system consists of a multi-antenna base station (BS) communicating with single-antenna users, which are divided into two groups: IDRs and EHRs. The BS concurrently sends energy and information signals to the users with the support of a deployed STAR-RIS.
The authors formulate an optimization problem to jointly optimize the energy/information beamforming vectors at the BS, the phase shifts at the STAR-RIS, and the common message rate to strike a balance between the users' sum rate and the total harvested energy. To solve this complex non-convex problem, a meta deep deterministic policy gradient (Meta-DDPG) approach is employed.
The simulation results validate that the proposed Meta-DDPG algorithm significantly enhances both data rate and harvested energy performance compared to the conventional DDPG approach. The integration of STAR-RIS with the Meta-DDPG algorithm yields superior results in terms of data rate and energy harvesting compared to the conventional RIS scenario.
Stats
The total transmit signal at the BS is given by x = wcsIDc + PU
u=1 wusIDu + PV
v=1 pvsEHv, where sIDc, sIDu, and sEHv are the common information signal, the private information signal of IDR u, and the energy signal of EHR v, respectively.
The received signal at IDR u is given by yIDu = hHu x + zIDu, where zIDu is the white Gaussian noise.
The received signal at EHR v is given by yEHv = fHv x + zEHv, where zEHv is the AWGN.
The achievable rate of the common message should not exceed the minimum rate of all IDRs, i.e., Rc ≤ minu{Rc,u}.
The total harvested energy at the v-th EHR is expressed as PHar
v (wu, pv, Θl) = λvE{PU
u=1 |fHv wu|2 + PV
v=1 |fHv pv|2}.
Citations
"The core message of this paper is to propose a novel system that incorporates a simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) with simultaneous wireless information and power transfer (SWIPT) using rate splitting multiple access (RSMA) to optimize both the sum rate of information decoding receivers (IDRs) and the total harvested energy at energy harvesting receivers (EHRs)."
"Simulation results validate that the proposed Meta-DDPG algorithm significantly enhances both data rate and harvested energy performance compared to the conventional DDPG approach."