Huawei 4G RS power calculation

[riverstreamer]

Hi,

I have seen in the forum and internet (like some Huawei documents) that the calculation of RS power in Huawei 4G/LTE is done through following formula (for Huawei) :

RS Power = Total power per channel (dBm) - 10 * log (total subcarrier) + 10 * log (PB + 1)

Question : For any 4G expert of Huawei RAN present, May I know what is the role of the part "10 * log (PB + 1)" ?
The PB should not have any influence on RS power ! Anyone knows why the notation is like PB+1 (the role of +1 in the equation) ?

Other point :
For what ever example that I saw for this formula, the PB is equal to 1 (3gpp and Huawei attribute says : PB = attribute {0,1,2,3} = equivelnt in ratio {5/4,1,3/4,1/2}).
So while attribute 1= ratio 1 then I could not understand if for PB in the formula, if I should use the attribute or the equivalent ratio; Meaning if PB = attribute 0 = ratio 5/4, then should I put 0 or 5/4 in the formula ?

With thanks for the help.
Cheers,