Handoff Dwell Time Distribution Effect on Mobile Network Performance

In this paper, the sensitivity of the handoff dwell time (HDT) model on wireless mobile network performance is studied. We present an approach on the basis of the universal approximation property of phase-type (PH) distribution in order to address the intractable numerical issue caused by HDT. We first obtain the steady state probability under the general HDT. The performance metrics from the perspective of base station (BS) as well as from the point view of call are developed. The PH-type HDT is then assumed to derive the numerically tractable expressions for the performance metrics. Finally, the truncated Gaussian HDT is approximately fitted by the PH distribution via expectation maximization algorithm to reuse the closed form analytical expression. The comparison shows that, in terms of the BS performance, the handoff blocking probability exhibits a significant discrepancy whenever one uses the exponential or truncated Gaussian HDT distribution, while the new call blocking probability is less sensitive to different HDT. In addition, HDT has little impact on the call performance with respect to the call completion probability and total waiting time. Both the analytical model and the approximation approach are verified by simulation.