New Technical Reports Evaluate Spectrum Sharing in 3.5 GHz Band

July 18, 2014 by NTIA

To support the Administration’s commitment to making available an additional 500 MHz of spectrum for commercial use by 2020, NTIA continues to perform and publish technical studies in bands proposed for sharing. In collaboration with a wireless technology provider, earlier this year NTIA performed ground-breaking interference-effects testing between radar signals and broadband digital communication receivers in the 3550–3650 MHz band. NTIA released two reports today that describe these measurements and analyses.

NTIA Technical Report TR-14-506, co-authored by Geoffrey A. Sanders, John E. Carroll, and Frank H. Sanders of NTIA’s Institute for Telecommunication Sciences in Boulder, Colorado, and Robert L. Sole of NTIA’s Office of Spectrum Management, presents the results of measurements and analyses of the effects of radar interference on prototype LTE equipment. NTIA Technical Report TR-14-507, co-authored by Frank H. Sanders, John E. Carroll, Geoffrey A. Sanders, Robert J. Achatz, and Robert L. Sole of NTIA and Lawrence S. Cohen of the U.S. Naval Research Laboratory, presents the results of measurements and analyses of the effects of LTE interference on a type of radar receiver that might eventually share spectrum with such systems.

Using this data, spectrum managers can refine and update the electromagnetic compatibility (EMC) analyses originally presented in NTIA’s Fast Track Report for possible future spectrum sharing between LTE and radars in the 3.5 GHz band. The reports do not identify interference protection criteria (IPC) for either the tested radar type or the tested LTE networks, but the measurement results may be used to guide the development of band-sharing EMC criteria. These data will be critically important to government and private-sector engineers and policy makers as spectrum sharing opportunities in the band are explored.  They will need to determine the conditions under which future LTE-type broadband systems may be able to share 3.5 GHz spectrum with high-power, incumbent government radar systems.

NTIA welcomes technical readers to review these data and share questions or comments with the authors.