SINR

def calculateFi(R, R_0_prim, c, freq):
    power_1 = (G_T + G_R - (s + Xf + Xh + L_T + L_R))/10
    power_2 = (G_T + G_R - (s + L_T + L_R))/10

    wavelght = c / (freq * 10**9)

    if(R/R_c > R_0_prim/R_c):
        fi = (R_0/R_c)**gamma * (wavelght/(4*math.pi*R_0_prim))**2 * 10**power_1
    else:
        fi = (wavelght/(4*math.pi*R_c))**2 * 10**power_2

    return fi