This letter investigates a novel wireless-powered quantum optical communication system, in which a batteryless quantum transmitter harvests energy from a classical radio-frequency source to transmit quantum coherent states. The transmission employs M-ary phase shift keying (M-PSK) modulation over an optical channel impaired by thermal noise, and the fundamental detection performance is evaluated using the Helstrom bound. An optimization framework is proposed that jointly determines the optimal quantum measurement and the energy-harvesting time fraction to maximize the effective rate under a block time constraint. Analytical expressions are derived for special cases, while semidefinite programming techniques are employed for the general M-PSK scenario. Numerical results validate the unimodal nature of the effective rate function and demonstrate the impact of the optimal design parameters.
This letter investigates a novel wireless-powered quantum optical communication system, in which a batteryless quantum transmitter harvests energy from a classical radio-frequency source to transmit quantum coherent states. The transmission employs M-ary phase shift keying (M-PSK) modulation over an optical channel impaired by thermal noise, and the fundamental detection performance is evaluated using the Helstrom bound. An optimization framework is proposed that jointly determines the optimal quantum measurement and the energy-harvesting time fraction to maximize the effective rate under a block time constraint. Analytical expressions are derived for special cases, while semidefinite programming techniques are employed for the general M-PSK scenario. Numerical results validate the unimodal nature of the effective rate function and demonstrate the impact of the optimal design parameters.
This paper develops a comprehensive analytical framework for a time-switching decode-and-forward quantum relay-assisted free-space optical communication system. In the proposed architecture, a batteryless relay harvests optical energy during a dedicated fraction of each transmission block and forwards quantum coherent states during the remaining time, enabling self-sustainable quantum relaying. Both hops are subject to Gamma-Gamma distributed atmospheric turbulence and additive Gaussian detection noise, while the relay and destination implement Helstrom-optimal quantum measurements that achieve the minimum symbol detection error. The framework unifies the effects of energy harvesting, turbulence-induced fading, and quantum-limited detection within a single performance model. Closed-form analytical expressions are derived for binary phase-shift keying modulation using the Helstrom bound, enabling tractable evaluation of the end-to-end error probability and the effective rate. The analysis establishes that the effective rate exhibits a strictly unimodal dependence on the harvesting fraction, yielding a unique optimal operating point that maximizes throughput under energy and noise constraints. Numerical results validate the theoretical findings and quantify the impact of turbulence severity, detection noise, and harvesting efficiency, demonstrating substantial performance gains over conventional non-harvesting quantum relays and providing new insights for energy-autonomous quantum optical networks.
This paper develops a comprehensive analytical framework for a time-switching decode-and-forward quantum relay-assisted free-space optical communication system. In the proposed architecture, a batteryless relay harvests optical en ergy during a dedicated fraction of each transmission block and forwards quantum coherent states during the remaining time, enabling self-sustainable quantum relaying. Both hops are subject to Gamma–Gamma distributed atmospheric turbulence and additive Gaussian detection noise, while the relay and destination implement Helstrom-optimal quantum measurements that achieve the minimum symbol detection error. The frame work unifies the effects of energy harvesting, turbulence-induced fading, and quantum-limited detection within a single performance model. Closed-form analytical expressions are derived for binary phase-shift keying modulation using the Helstrom bound, enabling tractable evaluation of the end-to-end error probability and the effective rate. The analysis establishes that the effective rate exhibits a strictly unimodal dependence on the harvesting fraction, yielding a unique optimal operating point that maximizes throughput under energy and noise constraints. Numerical results validate the theoretical findings and quantify the impact of turbulence severity, detection noise, and harvesting efficiency, demonstrating substantial performance gains over conventional non-harvesting quantum relays and providing new insights for energy-autonomous quantum optical networks
This paper investigates the performance of coherent-state quantum optical wireless communication systems operating over atmospheric turbulence channels with pointing errors (PEs). The average error probability (AEP) and average achievable rate (AAR) are analyzed for on–off keying (OOK) and binary phase-shift keying (BPSK) signaling under photon-counting (PC), homodyne, and optimal Helstrom detection. The proposed framework jointly incorporates deterministic path loss, atmospheric turbulence, and PEs, and accommodates multiple statistical channel models, including Gamma-Gamma (GG), doubly inverted Gamma-Gamma (IGGG), and Fisher-Snedecor F distributions, within a unified analytical formulation. Closed-form expressions for AEP and AAR are derived via direct probability density function (PDF)-based integration of the conditional error probability, along with high-photon-number asymptotic approximations that provide insight into performance scaling behavior. Numerical results validate the analytical expressions and demonstrate the impact of PEs on system performance. The analysis further enables systematic comparison between classical and optimal quantum detection schemes and quantifies the achievable performance gains under different channel conditions. These results provide useful design insights for modulation and receiver selection in turbulent free-space optical (FSO) communication systems.
This paper introduces a new framework for quantum simultaneous information and power transfer (QSIPT), enabling the joint use of quantum states for classical information and energy transfer in quantum communication systems. We propose a model in which quantum states simultaneously transmit classical information through a quantum channel and transfer energy to an energy harvesting (EH) receiver. The trade-off between communication rate and harvested energy is characterized by the capacity-power function, defined for both discrete-variable (DV) and continuous-variable (CV) quantum channels. For DV channels, we derive properties of the capacity-power function, providing analytical upper and lower bounds for the amplitude damping channel and an exact closed-form characterization for the quantum erasure channel. For CV channels, we extend the framework by introducing a generalized beam-splitter (BS) receiver with adjustable transmissivity, jointly optimized with a transmitter mean-photon-number budget, splitting the channel output between the information decoder and the EH receiver. We analyze the capacity-power and achievable-rate-power trade-off under various Gaussian encoding schemes, including coherent, squeezed, and thermal states, for both lossy bosonic and additive Gaussian noise channels. Closed-form expressions are derived for coherent-state encoding under the joint photon-number-budget and adjustable-transmissivity formulation; squeezed-state inputs are evaluated numerically. Our results show that, within the considered displaced Gaussian encoding class, coherent states achieve the best capacity-power trade-off, squeezed states do not outperform coherent-state encoding under the phase-insensitive channel and passive receiver architecture, and thermal states enable energy transfer without supporting reliable communication.
This paper investigates a quantum relay-assisted free-space optical (FSO) communication system in which a decode-and-forward relay is powered by time-switching optical energy harvesting and forwards the decoded information using displaced squeezed signaling (DSS). To obtain a physically con sistent description of turbulence-induced loss for non-classical signaling, each hop is modeled as a pure-loss bosonic chan nel whose random transmissivity follows a truncated Gamma Gamma law, i.e., the Gamma-Gamma irradiance conditioned on the physically admissible range of a transmittance. Under this channel, coherent states remain pure, whereas squeezed states are mapped to mixed Gaussian states. Under Helstrom-optimal detection, the average error of the coherent hop is derived in exact Laplace-series form. For the DSS hop, we derive the output states, a closed-form Gaussian fidelity with rigorous two sided bounds on the Helstrom error, and prove the existence of a loss-aware optimal photon partition. Furthermore, we prove that optimized squeezing preserves both the turbulence-induced diversity order and the leading asymptotic constant of coherent relaying, so that its benefit is a finite-photon-budget effect, and that an interior throughput-optimal harvesting fraction exists. A covariance-preserving benchmark with an exact series representation yields an analytical upper bound on the achievable throughput whose absolute gap vanishes as the relay photon budget grows. Numerical results based on the exact mixed-state Helstrom error quantify the benefit of squeezing and the regime in which it is useful.
The quest for finding a small-sized energy supply to run the small-scale wireless gadgets, with almost an infinite lifetime, has intrigued humankind since past several decades. In this context, the concept of Quantum batteries has come into limelight more recently to serve the purpose. However, the main issue revolving around the closed-system design of Quantum batteries is to ensure a loss-less environment, which is extremely difficult to realize in practice. In this paper, we present the modeling and optimization aspects of a Radio-Frequency (RF) Energy Harvesting (EH) assisted Quantum battery, wherein several EH modules (in the form of micro- or nano- sized integrated circuits (ICs)) help each of the involved Quantum sources achieve the so-called quasi-stable state. Specifically, a micro-controller manages the overall harvested energy from the RF-EH ICs and a photon emitting device, such that the emitted photons are absorbed by the electrons in the Quantum sources. In order to precisely model and optimize the considered framework, we formulate a transmit power minimization problem for an RF-based wireless system to optimize the number of RF-EH ICs under the given EH constraints at the Quantum battery-enabled wireless device. We obtain an analytical solution to the above-mentioned problem using a rational approach, while additionally seeking another solution obtained via a non-linear program solver. The effectiveness of the proposed technique is reported in the form of numerical results by taking a range of system parameters into account.