Patent ID: 8023948
Filing Date: 2011-09-20
Classification: H04W

Abstract:
1. A vertical handover method for an overlay communication system including a plurality of base stations each providing at least one communication network technology to a mobile terminal, comprising: determining if a mobile terminal is located in a measurement region with reference to a vertical handover map in relation to a serving base station; detecting reachable base stations by activating all network interfaces when the mobile terminal is located in a measurement region; selecting one of the reachable base stations as a handover target base station; determining if the mobile terminal is located in a handover region with reference to the vertical handover map; and performing a handover if the mobile terminal is located in a handover region, wherein the vertical handover map is a map configured by a graph in which an X axis denotes a Distance (D) between the serving base station and the mobile terminal, and a Y axis denotes a traffic Load (L) of the serving base station, wherein the measurement region is a region determined by the vertical handover map, wherein the handover region is a region determined by the vertical handover map, and wherein detecting reachable base stations comprises determining if there is a base station satisfying {└D