A cost-effective approach to selective IP paging scheme using explicit multicast

In this paper, we propose a cost effective IP paging protocol, which can be used for terminal paging in next-generation wireless IP networks. In the existing IP paging protocols, a paging request packet is delivered to access routers belonging to a paging area by unicast or multicast. However, unicast and multicast result in higher cost, so that we present a selective paging algorithm utilizing explicit multicast (xcast). Xcast is a new kind of multicast scheme for small sized groups which uses unicast with low maintenance overhead. In terms of the paging algorithm, we use a selective paging algorithm to minimize the paging cost, by dividing a paging area into several sub-paging areas, while meeting the paging delay bound. In addition, we propose flexible grouping algorithms. For the performance analysis, we develop analytical paging cost and delay models based on the random walk model. Using the models, we compare the selective IP paging scheme using xcast with the existing paging schemes that use unicast or multicast. The results indicate that the proposed scheme significantly reduces the paging cost compared with traditional schemes, especially when the transmission cost is relatively less than the processing cost and the delivery path is not long. In addition, our flexible grouping algorithms, which are adaptive to the session-to-mobility ratio, provide less paging cost and guarantee equal to or less paging delay compared with the existing schemes.