Jul 2026· La Main· pp. 1-9· 0 citations· 12 references
Abstract
Simultaneous Wireless Information and Power Transfer (SWIPT) enables IoT devices to harvest energy and exchange data over the same wireless infrastructure. In directional SWIPT networks, beam design induces a trade-off between concentrating power on a few users versus broadening energy the harvesting opportunities to a wider set of devices, especially under harvest-then-transmit operation. This paper proposes a framework to optimize user-beam association and scheduling of transmission and energy harvesting. As a concrete instantiation, we consider a SWIPT network with directional beams and formulate the corresponding proportional-fair beam design problem under a constraint on the number of active beams. We develop an exact dynamic-programming algorithm that computes the globally optimal non-overlapping beam partition, and we derive an instance-wise upper bound on the loss induced by the non-overlapping restriction under beam-independent scheduling. Numerical results show that the proposed solution closely tracks this benchmark over a broad range of SWIPT regimes, while highlighting the role of heterogeneity in user distance, density, spatial concentration, and scheduling choices. These findings indicate that non-overlapping beam designs can provide near-optimal performance with a tractable optimization structure.
Reconfigurable intelligent surface (RIS)-assisted wireless-powered communication networks (WPCNs) introduce a new degree of freedom: the same passive beamforming array can concentrate the downlink energy toward harvesting devices and simultaneously shape the uplink interference environment. In this paper, we study a system where the base station (BS) waveform serves the dual role of wireless energy transfer (WET) and passive target sensing. Using the position error bound (PEB) derived from the equivalent Fisher information matrix (EFIM) as the sensing quality metric, we formulate a joint resource allocation problem that maximizes weighted uplink sum-rate subject to a PEB constraint, energy-causality, block-time sharing, and unit-modulus RIS phase constraints. Focusing on the practically important WET-only sensing case, we show that the problem separates into four tractable subproblems and propose a block coordinate descent (BCD) algorithm: (i) closed-form water-filling for WIT time-power allocation, (ii) semidefinite relaxation (SDR) with Dinkelbach iterations for per-slot WIT-RIS beamforming, (iii) golden-section search for the optimal WET duration, and (iv) a convex SDP for WET-RIS optimization under a PEB constraint. The BCD iterates converge monotonically. Simulations confirm a fundamental rate–sensing tradeoff and demonstrate significant gains from joint RIS-assisted optimization.
Yongjie Li, Jing Shen, Jizhao Lu et al.· 2026 8th International Confe...· 0 citations
In multi-user wireless power transfer (WPT), scheduling schemes that determine the allocation of transmission resources among receivers play a crucial role in improving power transfer efficiency. Scheduling can be classified into time-division (TD) and space-division (SD) schemes, with the transmission order and direction designed to control when and to whom power is delivered. TD-WPT can exploit the nonlinear characteristics of rectennas by concentrating power in time; however, a system relying on highly directional transmission from a single location reduces robustness under time-varying channel conditions. This study investigated the effectiveness of spatio-temporal scheduling in coordinated multi-transmitter WPT systems. By employing multiple transmitters, the proposed method is robust against channel variations in delivering power. Moreover, coordinated beamforming among transmitters exploits inter-cluster interference. Simulation results demonstrate the potential of the proposed scheme for robust and efficient power supply, even under shadowing conditions.
Yuna Sawada, Shino Shiraki, N. Kikuma et al.· 0 citations
Integrated sensing, communication, and computation (ISCC) enables next-generation wireless networks to perform environmental perception while processing massive data under stringent quality-of-service (QoS) requirements. Energy consumption is a crucial indicator for the ISCC system design. However, accounting for energy heterogeneity in ISCC system design is an open problem. Specifically, battery-constrained user equipments (UEs) and energy-abundant access points (APs) require fundamentally different energy allocation strategies based on device computational capabilities, battery states, and QoS constraints. In this paper, we introduce a nonconvex energy cost minimization problem by considering a user-specific energy cost ratio coefficient that explicitly balances UE-AP energy consumption according to heterogeneous device energy states. To efficiently address this problem, a double-loop framework combining successive convex approximation and alternating direction method of multipliers is also developed. Numerical results demonstrate that the proposed scheme significantly outperforms the fixed offloading baselines (full offloading, full local and half offloading) in terms of the total energy cost. In particular, the proposed scheme achieves up to $25-47.6\%$ energy cost reduction at moderate latency constraints over fixed offloading baselines, thereby supporting time-sensitive applications. Moreover, this work provides an effective solution for energy-efficient and QoS-aware 6G ISCC systems serving diverse devices with conflicting energy priorities.
Kai Dong, Lei Wang, S. Vorobyov et al.· IEEE Transactions on Wireles...· 0 citations
With the increasing demand for efficient wireless communication services, researchers are actively seeking innovative solutions to optimize spectrum utilization. Two promising technologies, cognitive radio and non-orthogonal multiple access (CR-NOMA), have emerged as key enablers for next-generation wireless communication. By harnessing the available radio frequency spectrum, devices can cooperatively connect and communicate more efficiently, while also gathering energy to support green communication.
This study investigates the uplink simultaneous wireless power and information transfer (SWIPT) using a CR-NOMA system over Rayleigh fading channel, focusing on energy harvesting at the secondary transmitter (ST) as a cooperation node. Here, primary/secondary receivers (PR/SR) communicate with the ST, during first phase, which then utilizes the harvested power to transmit the primary data to the primary transmitter. This paper enhances the proposed system cell-edge user performance and derives analytical frameworks for outage probability, throughput, and ergodic capacity of PR, SR, respectively. Additionally, our results determine the optimal power allocation scheme to enhance the performance of PR/SR signals.
In this paper, we consider a backscatter communication (BackCom)-assisted uplink pinching-antenna system in Internet of Things (IoT), where a non-energy-constrained IoT device provides radio frequency signals to support multiple energy-constrained IoT devices, with multiple pinching antennas deployed on a waveguide. We formulate a joint optimization problem to select a energy-constrained device and simultaneously design its power reflection coefficient and pinching antenna locations. The objective is to maximize the achievable rate of the selected device, subject to the quality of service requirements of the non-energy-constrained device, minimum energy harvesting at energy-constrained devices, and collision-free constraints imposed on the pinching antennas. The problem is non-convex and analytically intricate, due to the strong interdependence among device selection, power reflection coefficients, and antenna positions. To overcome these challenges, we propose a block coordinate descent-based successive convex approximation algorithm that iteratively transforms the original non-convex problem into a series of convex subproblems that can be solved efficiently. Additionally, we analyze a special case with a single pinching antenna, deriving the optimal antenna location along with an approximate outage probability expression and the corresponding diversity order. Simulation results demonstrate that the proposed system achieves higher achievable rates, lower outage probability, and improved diversity gain compared to conventional uplink fixed-antenna systems.
Zheng Yang, Jingjing Cui, Gaojie Chen et al.· IEEE Transactions on Wireles...· 0 citations
The amalgamation of cooperative Non-Orthogonal Multiple Access (NOMA) with Simultaneous Wireless Information and Power Transfer (SWIPT) is a promising technology for addressing energy bottlenecks and extending the lifetime of wireless networks. The traditional Fixed Power Splitting (FPS) is the most widely adopted protocol in SWIPT-assisted cooperative NOMA systems due to its simplicity and ease of implementation. However, the fixed nature of its Power Splitting (PS) ratio makes it inefficient under dynamic wireless channel environments, leading to insufficient Energy Harvesting (EH) and reduced decoding capability, as it cannot adapt to fluctuating channel conditions. This study proposes an Adaptive Power Splitting (APS) protocol at the near user, where the PS ratio is dynamically adjusted in accordance with the instantaneous channel condition. This work considered a system model that consists of a single source, a near user acting as a Decode-and-Forward (DF) relay, and a far user. The APS protocol enables the near user to allocate energy for simultaneous EH and Information Decoding (ID). Closed-form expressions are derived for the Outage Probabilities (OPs) of the users under Rayleigh fading channels. Numerical evaluations are carried out to analyze the system outage performance in terms of Signal-to-Noise Ratio (SNR), energy conversion efficiency, user distance, PS, and Power Allocation (PA) ratio. Simulation results demonstrate that the APS NOMA scheme outperforms both the FPS NOMA and Orthogonal Multiple Access (OMA) schemes, reducing OP significantly across a range of SNRs, making it highly effective for reliable and energy-efficient communication in future wireless networks.
S. Ajibowu, O. Adeleke, M. Asafa et al.· Nigerian Journal of Technolo...· 0 citations