Hata Model is applied for GSM Link Budget,here i write about its formula and Cell Size Estimation.

Hata´S Empirical Formula

PL = 69.55 +26.6log10fc - 13.82log10hb + (44.9 – 6.55log10hb)log10R – a(hm) -CF

Where ,

fc – Frequency in MHZ

hb – Transmitter antenna height

hm – Receiver antenna height

R – Radius in Km

a(hm) is the correction factor for effective mobile antenna height

Solving backwards the cell radius is given by

log10R =  MAPL +CF – 69.55 +26.6log10fc + 13.82log10hb + a(hm) / (44.9 – 6.55log10hb)

Cell Size/Count Estimation

  • Once the Maximum allowable path loss is known, the achievable cell size can be evaluated.
  • Cell radius is calculated using MAPL and Hata’s empirical formula.
  • Cell radius is the distance from base station where the path loss equals MAPL. Beyond this radius, the signal is too weak to be acceptable.
  • Each area has a different correction factor.
  • Also the coverage objectives are usually different for Urban, Suburban and Rural areas.
  • Therefore MAPL has to be calculated for each area and then cell size determined separately.
  • Once the cell radius is calculated, cell count estimates can be made.
  • Once the cell radius for each area is calculated, then the minimum number of cells required to provide coverage can be determined.
  • For each area

A = 2.6R2

Where,

  1. R – radius of cell
  2. A – Area of the corresponding hexagon.
  • Cell count = Urban Area(Km2) + Suburban area(Km2) + RuralArea(Km2)
  • Cell Count = Aurban(Km2) + Asuburban(Km2) + Arural(Km2)