Performance Analysis of Millimeter Wave Wireless Power Transfer With Imperfect Beam Alignment
ABSTARCT :
In this paper, the impact of imperfect beam alignment (IBA) on millimeter wave (mmWave) wireless power transfer (WPT) is investigated. We consider a mmWave WPT network, where the location of the energy transmitters follows a Poisson point process. Instead of the mostly used flat-top antenna model, we adopt the Gaussian antenna model suggested by the 3rd Generation Partnership Project (3GPP) for better accuracy. Two beam alignment error (BAE) models, i.e., truncated Gaussian and uniform models, are introduced to represent different BAE sources. We derive the probability density functions (PDFs) of the cascaded antenna gain with both BAE models and then provide the approximated PDFs for tractability. With the help of Fox’s H function, the analytic expression for the energy coverage probability with nonlinear energy harvesting model is derived. Besides, we deduce a closed-form expression of the average harvested radio frequency (RF) energy. The simulation results verify our theoretical results and demonstrate the performance degradation incurred by BAE. It also shows that the flat-top antenna model cannot always provide accurate performance evaluation in the presence of BAE.
EXISTING SYSTEM :
? It can be observed that when the number of elements in the antenna array grows larger and the alignment errors exist, the mainlobe beamwidth becomes too narrow to guarantee the beam alignment.
? MILLIMETER-WAVE (mmWave) bands will play a significant role in future 5G networks, where the broad spectrum aims to mitigate traffic-related issues in existing sub-6 GHz networks.
? RFEH in a 28 GHz network has been investigated numerically demonstrating improved energy and information coverage over sub-6 GHz networks, promising improved end-to-end RFEH efficiency over existing cellular networks.
? In order to overcome the cost-barrier of mmWave rectennas fabricated on low-loss RF substrates, additive manufacturing has been used to realize mmWave rectennas for pervasive IoT
DISADVANTAGE :
? To the best of our knowledge, the impact of BAE on mmWave WPT system has not been investigated and well understood to date.
? Alternatively, using the antenna gain model suggested by the 3rd Generation Partnership Project (3GPP), investigated the impact of beam misalignment from interfering transmitters, and resorted to the curve-fitting method to derive the probability density function of the antenna gain with BAE.
? The reason is that the flat-top model lacks the capability of depicting the roll-off effect of the mainlobe and thus is not suitable for accurately evaluating the impact of BAE on mmWave systems.
? It means that minimizing BAE is one of the most crucial issues for mmWave WPT systems.
PROPOSED SYSTEM :
• To cope with the exponentially increasing demands for high data rate wireless accesses, several key techniques have been proposed .
• In particular, millimeter wave (mmWave) communication, which benefits from its numerous spectrum resources and short wavelength, is widely considered as one of the most important technologies to achieve 10Gbit/s peak date rate.
• So far, many efforts have been devoted to the research of mmWave communications.
• This is explained by the patch antenna’s higher dielectric losses discussed earlier; over 53.7% of the accepted power is dissipated in the patch’s textile substrate as opposed to only 32.4% of the power accepted by the proposed AVA.
ADVANTAGE :
? To evaluate the system-level performance of mmWave WPT, stochastic geometry has been utilized to capture the effects of propagation loss and blockage, which dominate the received signal power.
? Both works verified that mmWave could improve the performance of SWIPT compared to lower frequency solutions.
? Nevertheless, it may incur great inaccuracy for evaluating system-level performance.
? Therefore, some literature considers more realistic antenna patterns in the performance analysis of mmWave WPT.
? In, the microstrip patch antenna and end-fire antenna models were used to analyze the coverage performance of SWIPT.
? Therefore, it is necessary to investigate the performance of the mmWave transmission systems with imperfect beam alignment (IBA).
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