Optimization of the overall success probability of the energy harvesting cognitive wireless sensor networks

Wireless energy harvesting can improve the performance of cognitive wireless sensor networks (WSNs). This paper considers radio frequency (RF) energy harvesting from transmissions in the primary spectrum for cognitive WSNs. The overall success probability of the energy harvesting cognitive WSN depends on the transmission success probability and energy success probability. Using the tools from stochastic geometry, we show that the overall success probability can be optimized with respect to: 1) transmit power of the sensors; 2) transmit power of the primary transmitters; and 3) spatial density of the primary transmitters. In this context, an optimization algorithm is proposed to maximize the overall success probability of the WSNs. Simulation results show that the overall success probability and the throughput of the WSN can be significantly improved by optimizing the aforementioned three parameters. As RF energy harvesting can also be performed indoors, hence, our solution can be directly applied to the cognitive WSNs that are installed in smart buildings

Reflecting Surface Assisted Energy Harvesting with Optimized NOMA Downlink Transmissions

This paper studies an intelligent reflecting surface (IRS) assisted wireless communication system with multiple downlink data and energy harvesting users. We assume that base station uses non-orthogonal multiple access (NOMA) for transmission and downlink users employ successive interference cancellation to decode their information from the received signal. With this setting, our goal is to maximize the harvested energy at the energy harvesting users while guaranteeing the minimum rate requirements of the individual data users. We propose an alternating optimization based algorithm, where semidefinite relaxation is used to obtain the optimal beamforming design at the base station and the IRS. Specifically, an iterative rank minimization approach is used to obtain the optimal reflection phase vector at the IRS. The convergence of the proposed algorithm is also proved. Finally, the efficacy of the proposed algorithm is demonstrated with the help of simulation results.acceptedVersionPeer reviewe

Detection Probability Maximization Scheme in Integrated Sensing and Communication Systems

Dual functional radar communication (DFRC) is a promising approach that provides a viable solution for the problem of spectrum sharing between communication and radar applications. This paper studies a DFRC system with multiple communication users (CUs) and one radar target. The goal is to devise beamforming vectors at the DFRC transmitter in such a way that the radar received signal to noise ratio (SNR) is maximized while the minimum data rate requirements of the individual CUs are satisfied. Even though the formulated optimization problem is non-convex, it is shown that it can be solved optimally through semi-definite relaxation (SDR). Also, it is observed that there is no need to transmit dedicated probing signal for the radar detection.acceptedVersionPeer reviewe

Energy harvesting non-orthogonal multiple access system with multi-antenna relay and base station

In this paper, we consider downlink non-orthogonal multiple access cooperative communication system. The base station (BS) serves two types of users, which are named relay user (RU) and far user (FU). The BS and RU are equipped with multiple transmit antennas. The RU harvests energy from the BS transmissions to perform the relaying operation for the FU. We have considered 1) amplify-forward; 2) decode-forward; and 3) quantize-map-forward relaying protocols at the RU. As the BS and RU have multiple antennas, therefore we consider 1) beamforming and 2) random antenna selection strategies at the BS and RU. Closed form expressions for the outage probability are provided for the aforementioned relay protocols and antenna strategies. Further, we show that for certain data rate range of the relay and FU the quantize-map-forward relaying protocol can perform better than the other two relaying protocols

Minimization of Sum Inverse Energy Efficiency for Multiple Base Station Systems

A sum inverse energy efficiency (SIEE) minimization problem is solved. Compared with conventional sum energy efficiency (EE) maximization problems, minimizing SIEE achieves a better fairness. The paper begins by proposing a framework for solving sum-fraction minimization (SFMin) problems, then uses a novel transform to solve the SIEE minimization problem in a multiple base station (BS) system. After the reformulation into a multi-convex problem, the alternating direction method of multipliers (ADMM) is used to further simplify the problem. Numerical results confirm the efficiency of the transform and the fairness improvement of the SIEE minimization. Simulation results show that the algorithm convergences fast and the ADMM method is efficient

Joint Optimization of Radar and Communications Performance in 6G Cellular Systems

Dual functional radar communication (DFRC) is a promising approach that provides a viable solution for the problem of spectrum sharing between communication and radar applications. This paper studies a DFRC system with multiple communication users (CUs) and a radar target. The goal is to devise beamforming vectors at the DFRC transmitter in such a way that the radar received signal-to-clutter-plus-noise-ratio (SCNR) is maximized while satisfying the minimum data rate requirements of the individual CUs. With regard to clutter, we consider two scenarios based on the possibility of clutter removal. Even though the formulated optimization problems are non-convex, we present efficient algorithms to solve them using convex optimization techniques. Specifically, we use duality theory and Karush-Kuhn-Tucker conditions to show the underlying structure of optimal transmit precoders. In the proposed solution, it is observed that there is no need to transmit separate probing signal for the radar detection in both the considered scenarios. This results in reduction in the number of optimization variables in the problem. Moreover, we make use of the asymptotic equivalence between Toeplitz matrices and Circulant matrices to further reduce the complexity of the proposed algorithm. Finally, numerical results are presented to demonstrate the effectiveness of the proposed algorithms.acceptedVersionPeer reviewe

Low Overhead Drone Relaying in Urban and Suburban Environments

This paper studies a drone relay assisted cooperative wireless communication system. Specifically, a drone is used as the relay node to establish communication between the base station and an aerial mobile terminal under realistic channel models with the consideration of line-of-sight probability. The total transmission time is divided into smaller time slots and in each time slot the relay uses decode-and-forward protocol to forward the received information to the mobile terminal. Then, an optimization problem is formulated where the objective is to maximize the sum rate over the whole transmission time. The formulated problem is non-convex. However, we show that for several cases the global optimal solution can be achieved. Moreover, we develop a low-complexity algorithm to find suboptimal solutions for the other cases.acceptedVersionPeer reviewe

Bioequivalence Study of Deferiprone In Healthy Pakistani Volunteers

The study was conducted to evaluate the bioequivalence of deferiprone 500 mg with innovator drug in Pakistani men. Twenty four healthy volunteers were enrolled in this study. Each volunteer take two tablets of generic and innovator deferiprone with two-week washout period. Blood samples were collected at predetermined time intervals. Plasma deferiprone levels were analyzed using validated HPLC method. Pharmacokinetic parameters computed non-compartmentally after logarithmic transformation of data. The mean relative bioavailability was 104 %. The mean Cmax , AUC0–t , AUC0–∞ for generic drug were 14.41, 40.49, and 42.84 μg.h/mL and for innovator were 12.68, 38.63, and 40.75 μg.h/mL, respectively. Mean ratio (generic/innovator) of AUC0–t at 90 % CI was 0.9737-1.1150 and for Cmax was 0.99876- 1.2425. Hence, the mean ratio of 90 % confidence interval of AUC0–t and Cmax lie within the acceptable limit of (0.80-1.25) for bioequivalence. Therefore, it was concluded that Ferinil and Ferriprox was proved to be bioequivalent in healthy Pakistani men.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Bioequivalence Study of Deferiprone In Healthy Pakistani Volunteers

The study was conducted to evaluate the bioequivalence of deferiprone 500 mg with innovator drug in Pakistani men. Twenty four healthy volunteers were enrolled in this study. Each volunteer take two tablets of generic and innovator deferiprone with two-week washout period. Blood samples were collected at predetermined time intervals. Plasma deferiprone levels were analyzed using validated HPLC method. Pharmacokinetic parameters computed non-compartmentally after logarithmic transformation of data. The mean relative bioavailability was 104 %. The mean Cmax , AUC0–t , AUC0–∞ for generic drug were 14.41, 40.49, and 42.84 μg.h/mL and for innovator were 12.68, 38.63, and 40.75 μg.h/mL, respectively. Mean ratio (generic/innovator) of AUC0–t at 90 % CI was 0.9737-1.1150 and for Cmax was 0.99876- 1.2425. Hence, the mean ratio of 90 % confidence interval of AUC0–t and Cmax lie within the acceptable limit of (0.80-1.25) for bioequivalence. Therefore, it was concluded that Ferinil and Ferriprox was proved to be bioequivalent in healthy Pakistani men.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Optimal Joint Radar and Communications Beamforming for the Low-Altitude Airborne Vehicles in SAGIN

A symbolic feature that integrates the space, air and ground network components for service in challenging and remote areas is being envisaged with continuity and high mobility of the 6G mobile system. Simultaneously providing sensing and connectivity over the radio signal becomes essential to support the management of low-space air crafts in the mobile system with limited spectrum resources. In this paper, we investigate the optimal joint radar and communications beamforming scheme with the presence of the clutter to support the low-space airborne vehicles, e.g. unmanned aerial vehicles or drones that are essential components of Non-Terrestrial Networks. The proposed scheme achieves the optimal signal-to-clutter-plus-noise ratio of the sensing function while maintaining the performance of the predefined communications. The novel application of approximations and rank-reduction algorithms in this work maximizes the joint radar and communications performance, for a system model similar to the one that is solved with a local optimum solution in a previous work. The numeric simulation results show that our approach maintains low complexity while guaranteeing the global optimum beamforming solution.acceptedVersionPeer reviewe