Neighbor-assisted handoff in a cellular communications system
AssigneeTelefonaktiebolaget L M Ericsson
InventorsAnna M. Wejke, Claes Andersson
Life of this patent
Estimating the term…
Abstract
A handoff system where handoff requests are initiated not only by a home or serving base station, but also by neighboring base stations. As in conventional handoff, a serving base station may initiate a handoff request when the signal strength of one of its mobile stations falls below a predetermined threshold. In addition, neighboring base stations monitor the signal strength of neighboring mobile stations and request that a neighboring mobile station be handed off when that signal strength reaches a predetermined level. Thus, a handoff request may come from the serving base station because of a poor call connection or from a neighboring base station because of a possible strong call connection.
Claims23
A cellular mobile radio telephone system, comprising:
- a plurality of base stations assigned to corresponding geographical areas in said cellular system, each of said base stations including:
- means for monitoring signal connection parameters between mobile stations and itself;
- means for requesting a handoff of an associated mobile station currently being served by itself when one of said monitored signal parameters fails to satisfy a first variable predetermined threshold;
- and
- means for requesting a handoff for a neighboring mobile station currently being served by another base station when one of said monitored signal parameters satisfies a second variable, predetermined threshold;
- and
- a mobile switching center for coordinating communications between said mobile stations and said plurality of base stations including:
- means for receiving said handoff requests from said base stations serving mobile stations and said handoff requests from base stations serving said neighboring mobile stations, and
- means for determining whether to execute handoffs based on said signal parameters received from said serving base stations and from said base stations serving said neighboring mobile stations.
A cellular mobile telephone system having a plurality of differently-shaped, overlapping geographic cells, comprising:
- first means within each cell for detecting a signal parameter of call connections currently being served by each cell and for requesting a transfer of one or more call connections based on said detected signal parameter;
- second means within each cell for detecting said signal parameter of call connections associated with neighboring cells and for requesting a transfer of one or more call connections based on said detected signal parameter;
- and
- load balancing means for balancing a number of call connections associated with each cell including:
- means for receiving from said first means and second means said signal parameters of call connections associated with said serving cells and said neighboring cells, respectively;
- means responsive to transfer requests from said first and second means, for transferring call connections to neighboring cells based on said detected signal parameter and the number of unoccupied channels in each cell.
In a cellular mobile radio telephone system having a centralized switching center, a method for handing off call connections between mobile stations and serving base stations, comprising:
- detecting from neighboring base stations handoff requests and at least one signal parameter of a call connection between a mobile station and an associated, serving base station;
- determining a preferred, neighboring base station for handoff based on said at least one detected signal parameter from said neighboring base stations;
- and
- executing a handoff of said call connection from said serving base station to said preferred neighboring base station.
Dependencies are inferred from the claim text.