LTE impacts on GPS: final test report

Abstract

The mission of the National Advanced Spectrum and Communications Test Network (NASCTN) is to provide, through its members, robust test processes and validated measurement data necessary to develop, evaluate and deploy spectrum sharing technologies that can increase access to the spectrum by both federal agencies and non-federal spectrum users.The U.S. Department of Commerce's National Institute of Standards and Technology (NIST) and National Telecommunications and Information Administration (NTIA) established the Center for Advanced Communications (CAC) in Boulder, Colorado, to address, among other challenges, the increasing need for spectrum sharing testing and evaluation capabilities to meet national needs. As part of CAC's mission to provide a single focal point for engaging both industry and other government agencies on advanced communication technologies, including testing, validation, and conformity assessment, NASCTN was formed under the umbrella of the CAC. NIST hosts the NASCTN capability at the Department of Commerce Boulder Laboratories in Boulder, Colorado. NASCTN is a membership organization under a charter agreement. Members• Make available, in accordance with their organization's rules policies and regulations, engineering capabilities and test facilities, with typical consideration for cost.• Coordinate their efforts to identify, develop and test spectrum sharing ideas, concepts and technology to support the goal of advancing more efficient and effective spectrum sharing.• Make available information related to spectrum sharing, considering requirements for the protection of intellectual property, national security, and other organizational controls, and, to the maximum extent possible, allow the publication of NASCTN test results.• Ensure all spectrum sharing efforts are identified to other interested members.Current charter members are:• National Telecommunications and Information Administration (NTIA)• National Institute of Standards and Technology (NIST) AcknowledgmentsThe development and execution of this test methodology and data parsing and analysis required input from multiple types of expertise. Integrating and leveraging a wide range of technical skills was critical to the overall success of the project. Team members, while responsible for specific areas in their domain of expertise, were called upon to contribute to other technical and programmatic areas as needed to ensure the overall project success.Within the technical team, Dr. Daniel G. Kuester led the RF testbed design, including the automation and calibration processes; Dr. Adam Wunderlich headed up the data analysis, investigation into measurand behaviors, and presentation of collected data; Dr. Duncan A. McGillivray led the integration of devices under test (DUTs), optimization of the test operations for efficiency, and establishment of the GPS test conditions with Carlos Ruiz of the Electronic Proving Grounds at Fort Huachuca1; John Ladbury led the RF uncertainty analysis and supported calibration of the RF signaling chain; a...

Characterizing LTE user equipment emissions :

“…The same models of programmable attenuators used in a previous effort [24] were used in this effort. A conservative standard uncertainty of 0.5 dB is assigned to these attenuators.…”

Interference tests at room temperature applied to deployed low-noise receivers

“…4 Estimates of LTE uplink band 1 (low) (UL1) impacts on the median C/N 0 reported by DUT 16 in [1] for antenna aperture temperatures T a = 90 K, T a = 340 K, each shown with the original measurement results at T a = 300 K (shown transparent). .…”

“…When it is possible to assume that various receiver noise performance parameters lie within a constrained range, it may be signifcantly more practical to study the impacts of receiver noise by numerical simulation and not measurement. This technical note demonstrates this type of estimation with a case study on the anechoic test data in [1], in order to predict GPS "live sky" interference response based on anechoic chamber test behavior.…”

“…Recent work studied impacts of adjacent-band long-term evolution (LTE) cellular transmissions on GPS L1 receivers [1]. The results of the study are digital output responses of each GPS receiver for inputs that are mixtures of radiated GPS and LTE.…”

“…The antenna noise temperature test condition in [1] was carefully controlled. The shielded anechoic and semi-anechoic test environments were chosen in part to reject outside radiated noise.…”