MULTICAST HANDOFF METHOD IN MULTI-TIER CELL SYSTEM

摘要

PURPOSE: A multicast handoff method in a multi-tier cell system is provided to consider a cell number of a lower layer and loads of an upper layer and the lower layer, and to perform a handoff of a specific multicast group service to the upper and the lower layer. Therefore, it is possible to supply services to more users, and to improve channel efficiency. CONSTITUTION: In case that load of an upper layer reaches a specific threshold value, when a lower layer cell number of users included in a specific multicast group is smaller than the threshold value, a handoff is performed in the multicast group as lower layer cells. On the other hand, when loads of the lower layer cells are larger than the specific threshold value, a handoff is performed for the multicast group in the upper layer.