Handover mechanisms in next generation heterogeneous wireless ...

DYNAMIC NEIGHBOUR TRUST INFORMATION RETRIEVAL FOR GLOBAL ROAMING
Figure 4.9 The cumulative first-passage-time probabilities of entering into boundaries
[n=6]
With the transition matrix shown in Figure 4.8, Equation 4.10 can be used to calculate
the mean number of cell crossings incurred by single mobile user in the region. As
discussed early, the NTC exchange relies on a mobile user’s cell crossing. Therefore,
the number of cell crossings shows how many NTC exchanges may have been
performed. In Figure 4.10, the mean number of cell crossings incurred (before being
absorbed at the boundary) is compared with the total number of neighbour edges, which
is the minimum number of cell crossings required for establishing the complete network
trust pattern in the region and is determined by the size of rings. As the size of rings
increases, the number of neighbour edges grows much faster than the number of cell
crossings a mobile user can conduct. Larger is the region (measured by n), less
contribution can a mobile user make to the building of the network trust pattern. From
Figure 4.9 and Figure 4.10, it is found that the contribution of single mobile user to the
NTC distribution is quite limited due to its mobility pattern.
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