VERTICAL HANDOVER METHOD FOR OVERLAY COMMUNICATION SYSTEM
First Claim
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.
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Accused Products
Abstract
A vertical handover method in a heterogeneous overlay network communication system is provided. A vertical handover method for an overlay communication system including a plurality of base stations each serving at least one communication network technology to a mobile terminal includes determining whether 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 locates 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.
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Citations
25 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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9. 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:
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periodically measuring a received signal strength and a round trip time to a serving base station;
calculating an average distance between a serving base station and the mobile terminal and an average traffic load of the serving base station using the measured received signal strength and round trip time;
periodically comparing the average distance and the average traffic load to corresponding threshold values of a vertical handover map;
determining if the average distance and the average traffic load are greater than or equal to a measurement threshold distance and a measurement threshold traffic load, respectively;
detecting handover candidate base stations by activating all network interfaces if the average distance is greater than or equal to a measurement threshold distance or the average traffic load is greater than or equal to a measurement threshold traffic load;
selecting a candidate base station having an optimal condition as a handover target base station among the candidate base stations; and
performing a handover to the target base station if the average distance and the average traffic load exceeds a handover threshold distance or a handover threshold traffic load, respectively. - View Dependent Claims (10, 11)
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12. 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:
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calculating a distance between the mobile terminal and a serving base station and a traffic load of the serving base station;
detecting handover candidate base stations if the distance is greater than a first threshold distance or the traffic load is greater than a first threshold traffic load;
generating a candidate base station list including the handover candidate base stations;
selecting a target base station from the candidate base station list if the distance is greater than a second threshold distance or the traffic load is greater than a second threshold traffic load; and
performing a handover to the target base station. - View Dependent Claims (13, 14, 15, 16)
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17. 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;
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constructing a handover map in the form of a graph in which the X axis denotes a distance between the mobile terminal and a serving base station;
estimating a current distance between the mobile terminal and the serving base station and a traffic load of the serving base station;
projecting a coordinate consisting of the current distance and the traffic load to the handover map; and
performing a handover-related operation on the basis of a region of the handover map at which the coordinate is positioned. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification