Lee Sampling Rate Calculator for Drive Tests
Make sure your drive-test logging is fast enough for the speed and band.
Your numbers
Your results
Lee Sampling Rate Calculator for Drive Tests by TheCalcTools
How the Lee Sampling Rate Calculator for Drive Tests works
Enter the test frequency, vehicle speed and the number of samples per 40λ (36 minimum, 50 maximum).
The wavelength is 299.79 ÷ f (MHz) metres.
Sample spacing is 40λ ÷ n; the rate is speed ÷ spacing.
The formula
Worked example
Using the default values shown in the calculator:
| Frequency (MHz) | 1800 |
|---|---|
| Vehicle speed (km/h) | 40 |
| Samples per 40 wavelengths | 36 |
| Logger interval (ms) | 200 |
- λ at 1,800 MHz = 0.167 m; window 40λ = 6.66 m.
- With 36 samples, spacing = 0.19 m, so at 40 km/h you need 60.0 samples a second. A 200 ms logger allows up to 3.3 km/h. Too fast: reduce speed or the logger interval.
Result:
| Wavelength (m) | 0.167 |
|---|---|
| Averaging window 40λ (m) | 6.66 |
| Required sample spacing (m) | 0.19 |
| Required samples per second | 60.0 |
| Maximum speed at the logger interval (km/h) | 3.3 |
| Check | Too fast: reduce speed or the logger interval |
Frequently asked questions
What is Lee's criterion?
To measure the local mean of a fading signal, W. C. Y. Lee recommended 36–50 independent samples over a 40-wavelength window, which gives a mean estimate within about 1 dB.
Why does frequency matter?
Wavelength shrinks as frequency rises, so the spacing is smaller at 3.5 GHz than at 900 MHz, requiring faster logging or slower driving.
Sources and further reading
- W. C. Y. Lee, Estimate of local average power of a mobile radio signal (1985), IEEE Trans. Veh. Technol.
- Wikipedia: Drive testing
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