October 2017 | NTIA Technical Memo TM-18-526
Frank H. Sanders
Abstract: Future 3.5 GHz Citizens Broadband Radio Service Device (CBSD) transmitters in the U.S. will share spectrum with incumbent Federal radar systems. To avoid interfering with radar receivers in exclusion zones, CBSDs will be deployed in conjunction with Environmental Sensing Capability (ESC) sensors and associated Spectrum Access Systems (SASs). The ESCs and SASs will employ detect-and-avoid schemes for discovery of local radar signals leading to interference mitigation. But the term “detect” in this context is an oversimplification. In reality, there must be two stages in the discovery of radar signals by ESC-SAS combinations: first, a pulse burst detection stage based on a single burst and then a second stage in which detection of one or more radar pulse bursts causes an ESC-SAS to declare that a radar is present in a protection area on some frequency or frequencies. This Technical Memorandum draws the necessary distinction between the ESC pulse burst detection stage based on a single burst and the ESC declaration stage which may be based on multiple burst detections. It explains this distinction mathematically and relates probabilities of pulse burst detection to probabilities of radar declaration. It further describes the implications of this distinction for the testing and certification of ESCs with regard to the time required to test and certify ESC performance.
Keywords: radar; spectrum sharing; Spectrum Access System (SAS); Citizens Broadband Radio Service Devices (CBSD); environmental sensing capability (ESC); interference monitoring; dynamic protection area (DPA); probability of detection; probability of declaration; radar pulse burst
For technical information concerning this report, contact:
Frank H. Sanders
Institute for Telecommunication Sciences
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