# Chapter 12: Mobility Management in Wireless Networks¶

## Example 12.1, Page 374¶

In [1]:
import math

#Variable declaration
P=10000;  #Mobile density(mobiles/km**2)
R=500*10**-3; #km
V=10;  #Average moving velocity of a mobile in Kmph
Nc=10.; #No of cells per LA
N_LA=5; #Number of LAs per MSC/VLR

#Calculations&Results
#Number of transactions and duration of each transaction to MSC/VLR per LU for different LU types are given in Table 12.1.(page no.374)

# L=length (km) of the cell exposed perimeter in an LA
L=6*R*(1./3+1./(2*math.sqrt(Nc)-3));   #Km
# lamdaLU=number of transactions processed by MSC/VLR in an LA perimeter of the jth cell per hour
LamdaLu=V*P*L/math.pi;  #Lus per hour

# case(1)
print "Case-1"
R1_LU=LamdaLu/3600*(1*600./1000); #resource occupancy from Table 12.1
print 'The resource occupancy in the jth cell due to MS LUs is  %.1f Erlangs'%R1_LU;

#case(2)
print "\nCase-2"
R2_LU=LamdaLu/3600*(0.8*3500/1000+0.2*4000/1000);  #from Table 12.1
print 'The resource occupancy in the jth cell due to MS LUs is  %.2f Erlangs'%R2_LU;
Np=6*math.sqrt(Nc/3)-3;#Number of cells located on perimeter of an LA
print 'Number of cells where inter-VLR LUs occur will be: %d'%(round(0.5*Np*4));
print 'Number of cells where intra-VLR LUs occur will be: %d'%(4*Nc-16);
TNLU=LamdaLu*(2*24+16*(0.8*14+0.2*16));  #from table 12.1
print 'The MSC/VLR transaction load using the ﬂuid ﬂow model is %.2e transactions at peak hour'%TNLU;

Case-1
The resource occupancy in the jth cell due to MS LUs is  10.1 Erlangs

Case-2
The resource occupancy in the jth cell due to MS LUs is  60.55 Erlangs
Number of cells where inter-VLR LUs occur will be: 16
Number of cells where intra-VLR LUs occur will be: 24
The MSC/VLR transaction load using the ﬂuid ﬂow model is 1.69e+07 transactions at peak hour