Const Precision_FR = 0.001
Const max = 135
'Block rate of radio interface,known TCH and Erlang
Function Pbloc(t As Single, Nc As Integer)
Dim P As Single
Dim i As Integer
P = t / (1 + t)
For i = 2 To Nc
P = t * P / (t * P + i)
Next
Pbloc = P
End Function
'Erlang offered by N THC, in the condition of block rate=blk
Function Offered(N As Integer, blk As Single)
Dim An As Single, A As Single, Perc As Single
An = 0.5 * N / (1 - blk): A = 0.5 * N / (1 - blk)
Perc = Pbloc(An, N)
Do
If Perc > blk Then An = An - A Else An = An + A
Perc = Pbloc(An, N)
A = A / 2
Loop While Abs(Perc - blk) / blk > Precision_FR
Offered = An
End Function
'Channels for Erlang=A and block rate=blk
Function Channels(A, blk As Single)
Dim N As Integer, Perc As Single
N = 1: Perc = A / (A + 1)
While Perc >= blk
N = N + 1
Perc = A * Perc / (N + A * Perc)
Wend
Channels = N
End Function