Signaling and Handoff Rates at the Policy Control Function (PCF) in IP Multimedia Subsystem (IMS)

Within the IP multimedia subsystem (IMS), a next generation wireless service oriented framework, the policy control function (PCF) authorizes and controls the users´ flows in the IP network and enables roaming partnerships with other operators. To perform these tasks, the PCF servers should be designed to accommodate varying incoming signaling rates which depend on both the service request and the handoff rates. The handoff rate is a complex function of the number of access gateways, service duration, and mobility. In this paper, we develop for the first time an analytical model of the signaling and handoff rates at the policy server by considering all these factors. Our results show that increasing the number of gateways can result in non-linear increase in the signaling rate.