Performance evaluation of pipeline paging under paging delay constraint for wireless systems

In this paper, we present a simple pipeline paging (PP) scheme, in which multiple paging requests (PRs) can be served in a pipeline manner in different paging areas. We analytically model the blanket paging (BP) scheme, the sequential paging (SP) scheme, and the PIP scheme so that discovery rate, total delay, paging delay, and cost are derived analytically as functions of traffic load. Extensive simulations are carried out to verity our analytical results. Our study shows that the PIP scheme outperforms both the BIP and SIP schemes in terms of discover rate while maintaining the same cost as the SIP scheme. The PIP scheme outperforms the SP scheme in terms of total delay and has a lower total delay than the BIP scheme when traffic load is high. We also show that, when the paging delay constraint D is large enough, the PIP scheme achieves almost 200 percent of discovery rate and 50 percent of cost of the BP scheme, whereas discovery rate of the SIP scheme is far less than that of the BP scheme. Furthermore, we solve the following two-optimization problems for the PIP scheme: 1) the minimization of discovery rate with a bound on total delay and 2) the minimization of cost with a bound on total delay. In case the cost factor is not considered but total delay is important, we propose an adaptive scheme: When the traffic is lower than a threshold, the BIP scheme is adopted; otherwise, the PIP scheme is used. In this case, the threshold value is explicitly derived.