Handover mechanisms in next generation heterogeneous wireless ...

DYNAMIC NEIGHBOUR TRUST INFORMATION RETRIEVAL FOR GLOBAL ROAMING
the experiment. These values were particularly selected because of the impact of the
size of a region on the number of mobile users required for the NTC distribution as
shown in Figure 4.13. Figure 4.14 shows that the NTC PCT for the region is cut down
when the number of mobile users increases. The effect of adding more mobile users for
facilitating the NTC distribution is the most prominent when the number of mobile
users per cell is above the minimum number needed. It is observed the NTC PCT when
the mobile users were having different MCRTs. Generally, mobile users with high
MCRT require less time to get the NTC data distributed. This means that the mobility
pattern of a mobile user plays a role in determining the NTC PCT. However, the role of
the MCRT in determining the NTC PCT tends to be less important when the number of
mobile users per cell increases to a certain extent, e.g. 2 for the region of 10 rings, and
3.2 for the region of 6 rings as shown in Figure 4.15.
Figure 4.15 Number of mobile users per cell vs. regional NTC pattern construction time
Next, the experiment moves on to evaluate the accuracy of the PSMN in the NTC
distribution. As discussed early, mobile users in a dormant state can be chosen to
participate in the NTC distribution. However, under the PSMN, Equation 4.7 has to be
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