Publications

Abstract: This report describes speech intelligibility testing conducted on the Adaptive Multi-Rate (AMR) speech coder in several different environments simulating emergency response conditions and especially fireground conditions. The intelligibility testing protocol was the Modified Rhyme Test (MRT). Conditions included background noises of various types, as well as a mask associated with a self-contained breathing apparatus. Analog FM radio transmission and Project 25 digital radio transmission were also included in the test as reference points.

Nicholas DeMinco, Paul M. McKenna, Robert T. Johnk, Chriss A. Hammerschmidt, J. Wayde Allen, Linh P. Vu

Abstract: This report describes a modified rhyme test (MRT) conducted to characterize the behavior of digital and analog communication in the presence of background noise and moderate RF channel degradation. This is done through the use of reference systems to provide a manufacturer-independent perspective on this issue.

Abstract: NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement Sciences system to collect spectrum occupancy data for radio frequency assessments. This report shows measured frequency data spanning spectrum from 108 MHz to 10 GHz in the vicinity of Denver, Colorado, during the month of June 2011.

Report re-issued with six corrected images in March 2014.

Abstract: NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement Sciences system to collect spectrum occupancy data for radio frequency assessments. This report shows measured frequency data spanning spectrum from 108 MHz to 10 GHz in the metropolitan area of San Diego, California, during the months of May and June 2012..

Report re-issued with three corrected images in March 2014.

Abstract: In response to proposals to introduce new radio systems into 3550–3650 MHz radio spectrum in the United States, the authors have performed measurements and analysis on effects of interference from a variety of radar waveforms to the performance of a Long Term Evolution (LTE) base station receiver. This work has been prompted by the possibility that LTE base station receivers may eventually share spectrum with radar operations in this spectrum range. The base station receiver that was tested used time division duplex (TDD) modulation.

Abstract: This report presents spectrum occupancy data of the 3550–3650 megahertz (MHz) maritime radar band measured in June 2012 near San Diego. In this band, the military operates SPN-43 air marshaling radar systems with well-defined signal characteristics. A measurement system and frequency-swept technique were designed specifically to detect SPN-43 emissions.

Abstract: NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement System to collect spectrum occupancy data for radio frequency assessments. This report shows measured frequency data spanning spectrum from 108 MHz to 10 GHz in the metropolitan area of Chicago, Illinois, during a two week period in September 2012.

Abstract: In response to proposals to introduce new Long Term Evolution (LTE) microcell Citizens Broadband Service (CBS) radio systems into 3550–3650 MHz (3.5 GHz) radio spectrum in the United States, the authors have performed measurements and analysis on effects of LTE interference on the performance of a type of radar receiver that might eventually share spectrum with such systems. LTE and Gaussian noise interference were injected into a radar receiver; Gaussian noise was a proxy for aggregated interference sources and one type of LTE.

This report is the latest edition of our Digital Nation series, and it is based on data collected by the U.S. Census Bureau at the request of NTIA. Against this backdrop of data, today’s Internet-connected society raises a range of significant policy issues, including questions about spectrum use, universal service, copyright, privacy, security, and the economy itself.