Available Technology

METHOD AND APPARATUS FOR OPTIMAL DYNAMIC SPECTRUM ACCESS IN LTE SYSTEMS

Long Term Evolution (LTE) systems do not share their idle Physical Resource Blocks (PRBs) with other users. This is a waste of scarce spectrum resources. When the idle PRBs of LTE system are used by a Secondary User (SU), then the LTE spectrum utilization goes up. Thus, this invention solves the problem of spectrum scarcity by increasing spectrum utilization. It provides guaranteed Quality of Service (QoS) to the Primary User (PU) LTE systems in terms of limiting the probability of interference to the LTE system below a set threshold. Hence it can ease some of the concerns that the LTE operators with sharing their spectrum.

This invention uses a non-parametric estimation of the cumulative hazard function from survival analysis to compute the probability of successful transmission of an SU in a PRB. Using this information an optimal PRB allocation scheme is proposed. Using this scheme, an SU can maximize the number of PRBs it can use to transmit while keeping the probability of successful transmission above a set threshold on each LTE channel (or equivalently keeping the probability of interference to the PU below a set threshold). This does not require any changes to the PU LTE system. Thus, it can be implemented in an SU transparent to the PU LTE system. The method is very simple, hence can easily be implemented in a practical dynamic spectrum access (DSA) system.

Patent Abstract: 

New strong, light, and compact formed carbon fiber components require shorter, higher-aspect ratio carbon fibers. Shorter carbon fibers must be aligned to realize the desired tensile strength. Before this invention, industry lacked a tool to characterize carbon fiber alignment for inline quality assurance or for verification of alignment in 3D parts. This invention solves that problem through the implementation of scanning microwave ellipsometry. The implementation uses a polarized electric microwave field and measures the reflection of that field off a sample under test as a function of angle. The resulting reflected power plotted versus measured angle on a polar plot can have an elliptical shape. Leveraging this idea, NIST designed a test head that rotates the electric microwave field relative to the sample without rotating the sample. To raster the test head over a sample, NIST placed the test head on a 6-axis robotic arm. To use this implementation, NIST wrote an algorithm that fit the microwave ellipsometry data. The algorithm produces four discrete measurands that can be plotted as function of position in three-, two-, or one- dimension. The measurands are the maximum value, the minimum value, the alignment value, and the orientation value. While the target application is directed at carbon fiber, scanning microwave ellipsometry to industrial materials is broadly applicable to any use case where large-scale imaging of material properties is useful.

Benefits 

Current practice is to image the material on a light table. Light table imaging does not provide quantitative data for analysis, only relative information. Image processing techniques average over the image or segment the image. Light table imaging fails when the host matrix is not optically transparent or if the material is too dense.

Inventors: 

Sahoo, Anirudha; Hall, Timothy Alan; Hagwood, Robert Charles

Patent Number: 
Pending (Serial Number 16/841,106 and Publication Number 2020-0329382 A1)
Technology Type(s): 
Advanced Communications, Networking, and Physics
Internal Laboratory Ref #: 
19-031US1
Patent Status: 
Published Patent Application
Phone: 
301-975-2573
Email: 
tpo@nist.gov
Lab Representatives
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