Estimation of user equipment handover time from LTE network to cognitive radio network

This paper presents a model for handover time estimation when user equipment switches from a long term evolution (LTE) or fourth generation (4G) network to a cognitive wireless network (CWN). This procedure is relevant for a mobile tactile Internet, for example. The discussed handover can be characterized as an intersystem vertical handover. The intersystem handover is a terminal switching procedure between networks with different radio access technologies and authorization methods at a given location. A standard for a regional CWN was officially approved by international Institute of Electrical and Electronics Engineers (IEEE) in 2011 and is based on the using of “white spaces”. “White space” is a temporary unused television (TV) channel that was originally assigned to the TV broadcasting. The paper shows the synthesis process for the basic procedure of setting up an IP-session in a regional CWN and initiating a dynamic traffic flow. Another phase of the discussed procedure involves the releasing of a 4G mobile network resources after IP session was established in a regional CWN. A vertical handover procedure is presented as a sequence of 39 signaling messages spanning the time period from the discovery of CWN to the full completion of switching procedure and service delivery continuation at the CWN. Unlike the estimation methods for open queueing network, the proposed method includes not only the main foreground traffic but the background traffic too. An estimation of switching time was obtained for several service time distribution functions.