Hata Model predicts the total path loss along a link of terrestrial microwave or other type of cellular communications. And is a function of transmission frequency and the average path loss in urban areas.
This particular version of Hata model is applicable to the transmissions just out of the cities and on rural areas where man-made structures are there but not so high and dense as in the cities. To be more precise, this model is suitable where buildings exist, but the mobile station does not have a significant variation of its height.
Frequency: 150 MHz to 1.5 GHz
Hata Model for Suburban Areas is formulated as,
LSU = Path loss in suburban areas. Unit: decibel (dB)
LU = Average Path loss in urban areas. Unit: decibel (dB)
f = Frequency of Transmission. Unit: megahertz (MHz).
This model is based on Hata Model for Urban Areas and uses the median path loss from urban areas.
Introduction to RF propagation, John S. Seybold, 2005, John Wiley and Sons Inc.
 Hata, M.: Empirical Formula for Propagation Loss in Land Mobile Radio Services. IEEE Trans. Vehicular Technology, VT-29, pp. 317 - 325, 1980.