Publications

This report describes a set of algorithms developed at NTIA for the analytic assessment of interference effects in satellite communication services. These algorithms convert the interference levels at the receiver input into an observable performance degradation of the receiver output, such as, bit errors or distortion of the voice output.

This report, a follow-on of two earlier reports, examined the impact on fixed and mobile services of relaxing the current power-flux-density limits from satellites in the region of 2 GHz. The results of these studies were used to support U.S. contributions into the International Radio Consultative Committee (CCIR).

The Technical Spectrum Efficiency Factor (TSEF) concept was developed in the Technical Subcommittee (TSC) of the Interdepartment Radio Advisory Committee (IRAC) and was applied, by NTIA, to government fixed telecommunications systems in the 7-8 GHz bands. Both computer automated and manual procedures were employed. The TSEF evaluates the technical spectrum efficiency of a spectrum-using system by comparing the amount of the spectrum it uses to that used by the most spectrum-efficient system that could be procured to accomplish the same mission. The "most spectrum-efficient" system is called "the reference system". An extensive catalog of spectrum conservation techniques is also included.

The possibility of allowing shipborne navigation radars within the 9300-9320 MHz band is being considered within Study Group 8 of the International Radio Consultative Committee (CCIR) and within the United States preparation for the 1987 Mobile World Administrative Radio Conference. The impact this would have upon beacon systems used within the aeronautical radionavigation service is of concern. The report provides the background, equipment characteristics, and an analysis of the potential interaction between the shipborne radars and the aeronautical beacon systems.

Before 1987 no commercial trunking systems were available in any Govenment or non Government band below 800 MHz. This study examined the application of trunking to the Government band 406-420 MHz. As a result of this study and subsequent discussions with industry, commercial trunking systems were developed for the Government.

This report documents an effort to measure the operational and performance characteristics of radios equipped with the Data Encryption Standard (DES), as applied to government land-mobile operations. The purpose of these tests was to compare selected operational and performance characteristics of the digital (or guarded) mode of operation with those of the analog (or clear) mode of operation for each radio under test. The measurement results are discussed relative to spectrum management issues involving the use of spectrum allocated to the Federal Government fixed and mobile services and the corresponding rules of use. This measurement effort is the first phase of an on-going program to investigate the effect of using digital modulation schemes in a predominantly analog land-mobile environment.

This report is a study of the potential for sharing in the 4500-4800 MHz band between the fixed-satellite service (FSS) and terrestrial (fixed and mobile) services. The report focuses on decisions of the WARC-ORB-85 concerning planning of the FSS in this band. The report concludes that sharing of the 4500-4800 MHz band by the fixed, mobile and fixed satellite services will continue to be feasible.