Report ITU-R SM.2256-2 (06/2026) Spectrum occupancy measurements and evaluation
Foreword
Policy on Intellectual Property Right (IPR)
Summary
TABLE OF CONTENTS
1 Introduction
2 Terms and definitions
     2.1 Spectrum resource
     2.2 Frequency channel occupancy measurement
     2.3 Frequency band occupancy measurement
     2.4 Measurement area
     2.5 Duration of monitoring (TT)
     2.6 Sample measurement time (TM)
     2.7 Observation time (TObs)
     2.8 Revisit time (TR)
     2.9 Occupancy time (TO)
     2.10 Integration time (TI)
     2.11 Maximum number of channels (NCh)
     2.12 Transmission length
     2.13 Threshold
     2.14 Busy hour
     2.15 Access delay
     2.16 Frequency channel occupancy (FCO)
     2.17 Frequency band occupancy (FBO)
     2.18 Spectrum resource occupancy (SRO)
3 Measurement parameters
     3.1 Selectivity
     3.2 Signal to noise ratio
     3.3 Dynamic range
     3.4 Threshold
          3.4.1 Pre-set threshold
          3.4.2 Dynamic threshold
     3.5 Measurement timing
     3.6 Directivity of the measurement antenna
4 Site considerations
5 Measurement procedure
     5.1 FCO measurement with a scanning receiver
     5.2 FBO with a sweeping analyser
     5.3 FBO with FFT methods
6 Calculation of occupancy
     6.1 Combining measurement samples on neighbouring frequencies
     6.2 Classifying emissions in bands with different channel widths
7 Presentation of results
     7.1 Traffic on a single channel
     7.2 Occupancy on multiple channels
     7.3 Frequency band occupancy
     7.4 Spectrum resource occupancy
     7.5 Availability of results
8 Special occupancy measurements
     8.1 Frequency channel occupancy in frequency bands allocated to point-to-point systems of fixed service
     8.2 Separation of occupancy for different users in a shared frequency resource
     8.3 Spectrum occupancy measurement of WLAN (wireless local area networks) in 2.4 GHz ISM band
     8.4 Determining the necessary channels for the transition from analogue to digital trunked systems
     8.5 Estimation of RF use by different radio services in shared bands
9 Uncertainty considerations
10 Interpretation and usage of results
     10.1 General
     10.2 Interpretation of occupancy results in shared channels
     10.3 Using occupancy data to assess spectrum utilization
11 Conclusions
Annex 1  Impact of measurement parameters on accuracy and confidence level
A Preface
A1 Statistical approach to define spectrum occupancy
A2 Impact of the measurement timing
A3 Accuracy and confidence level
A4 Parameters affecting the statistical confidence of occupancy measurement
     A4.1 Pulsed and lengthy signals and signal flow rate
     A4.2 Relative instability of revisit time
A5 Measurement considerations
     A5.1 Radio channels with lengthy signals
          A5.1.1 Data collection and occupancy measurement rule for the case of small instability of the revisit time
          A5.1.2 Data collection and occupancy measurement rule for the case of meaningful instability of the revisit time
          A5.1.3 Selecting the number of samples on the base of the expected signal flow rate
          A5.1.4 Impact of signal flow rate in the radio channel and sample dependence on the confidence level of spectrum occupancy evaluations
               A5.1.4.1 Case A: One single signal present in the integration time
               A5.1.4.2 Case B: Twelve signals throughout the integration time
               A5.1.4.3 Case C: Several dozen signals throughout the integration time
     A5.2 Radio channels with pulsed signals
          A5.2.1 Data collection and occupancy measurement rule
          A5.2.2 Selecting the number of samples on the base of the expected occupancy level
     A5.3 Selecting the number of samples in the absence of a priori information on an occupancy level
     A5.4 Effect of reduced number of samples on the confidence level and the occupancy measurement error
Reference to Annex 1