Energy efficiency maximisation for STAR‐RIS assisted full‐duplex communications

Abstract

Reconfigurable intelligent surface (RIS) has emerged as a promising technique for enhancing the performance of wireless networks. However, the traditional reflecting‐only RIS requires that the transmitter and receiver ought to be on the same side of the RIS, limiting the flexibility of RIS deployment. To overcome this drawback, a new simultaneous transmission and reflection reconfigurable intelligent surface (STAR‐RIS) has been proposed. Different from STAR‐RIS assisted half‐duplex systems in the existing literature, this work investigates a novel STAR‐RIS aided full‐duplex (FD) communication system. An FD base station (BS) communicates with an uplink (UL) user and a downlink user simultaneously over the same time‐frequency dimension assisted by a STAR‐RIS. The authors aim to maximise the energy efficiency by jointly optimising the transmit power of the BS and the UL user and the passive beamforming at the STAR‐RIS. The authors decouple the non‐convex problem into two subproblems and optimise them iteratively. The Dinkelbach's method is used to solve the power optimisation subproblem, whereas the penalty‐based method and successive convex approximation are applied to design the passive beamforming. The convergence and complexity of the proposed algorithm are also analysed. The simulation results demonstrate the superior performance of the proposed scheme compared with other baseline schemes.

Going Beyond a Simple RIS: Trends and Techniques Paving the Path of Future RIS

“…1) [114] 2) [102] 3) [103] technologies such as energy harvesting/scavenging [125], [126], energy-efficient algorithms for network management [127], [128] and STAR-RISs for SWIPT [128], [129] have been in research to pave the path for a green and sustainable wireless networks. These technologies should be explored more for enabling energy-efficient solution.…”

Energy Efficient Resource Allocation for Re-configurable Intelligent Surface-Assisted Wireless Networks

“…The EE problem formulation respect to transmit power P and fixed RIS phase shift matrix, and Dinkelbach algorithm for solving the problem is presented in [4]. Dinkelbach algorithm as a fractional programming tools is widely used for optimization of wireless networks [18,19,20,21] The Backtracking line search Algorithm, Trust region method, the GAW-based EE maximization algorithm, and the TR-based EE maximization algorithm represented in Table 2, Table 3, Table 4, and Table 5, respectively . Table 2: Backtracking Line Search.…”

Performance Analysis of Full Duplex Bidirectional Machine Type Communication System Using IRS with Discrete Phase Shifter

“…The energy efficiency of the STAR-IRS-FD system is maximized by optimizing the transmit power of the BS and UL users as well as passive beamforming at IRS [15]. To optimize power, Dinkelbach's method is used, whereas, for passive beamforming, the penaltybased method and successive convex approximation are used.…”

“…The energy efficiency of an IRS-aided point-to-point system, where the transmitter and receiver are both outfitted with multiple antennas and operate in FD mode, is enhanced through joint beamforming at sources and IRS [16]. For optimization, the authors adopted a similar approach as employed in [15]. The suggested scheme's energy efficiency is demonstrated to be superior to the sum rate maximization scheme.…”