Signaling Reduction in Idle Mode for Inter-Technology Mobility

With the proliferation of air interface technologies, there are increasingly multi-mode user equipment devices (UEs) that can operate in more than one technology, although not at the same time. To save battery life, the UEs will camp in only one technology at any point in time even when there is coverage of multiple technologies. One key requirement is to limit the uplink signaling when UEs capable of operating in multiple radio access technologies perform inter-technology handovers in idle mode. In this paper, we propose a scheme that reduces this signaling by sending an inter-technology update to the network only when the UE loses coverage of the previously used technology. We also analyze the performance benefits of this scheme with that of the approach of camping on the preferred technology whenever coverage of that technology is available.