Study on unified under layer trigger mechanism for handover optimization in mobile IP networks

In order to reduce the handover latency to support the real-time application, Layer 2 trigger was proposed to help Layer 3 handover. However, the current Layer 2 trigger mechanism has two major problems. One is that Layer 2 trigger has non-unified interface with upper layer. And the other is that single parameter based trigger is not efficient to provide accurate information in heterogeneous network environments. In this paper, we present the new under layer trigger mechanism based on the Layer 2.5 framework to provide the unified trigger interface with the upper layer. The novel enhanced trigger concept including multi-dimension triggers is also proposed to provide more accurate indications. The procedure of IP layer handover is partitioned into three phases which can be accelerated by adopting trigger mechanism. Finally we give the examples of the use of these triggers