EP0504122A2
Expired / Lapsed
EP
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Neighbor-assisted handoff in a cellular communications system
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1992-03-10
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Granted: —
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Expires: 2012-03-10
Abstract
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.
Inventors
- 👤 Anna Fallgren
- 👤 Claes Andersson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 18:45
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/24; H04W36/30; H04W36/302; H04W36/04; H04W36/34; H04W36/38
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
163 words
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 said base stations; means for requesting a handoff of an associated mobile station currently being served by said base station when one of said monitored 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 parameters satisfies a second variable, predetermined threshold; and a mobile switching center for coordinating communications between said plurality of mobile stations and said plurality of base stations including: means for receiving said handoff requests from said serving base stations and said handoff requests from said neighboring base stations, and means for determining whether to execute handoffs based on said signal parameters received from said serving and neighboring base stations.
Claim 2
Dependent Claim
163 words
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 said base stations; means for requesting a handoff of an associated mobile station currently being served by said base station when one of said monitored 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 parameters satisfies a second variable, predetermined threshold; and a mobile switching center for coordinating communications between said plurality of mobile stations and said plurality of base stations including: means for receiving said handoff requests from said serving base stations and said handoff requests from said neighboring base stations, and means for determining whether to execute handoffs based on said signal parameters received from said serving and neighboring base stations.
Claim 3
Dependent Claim
20 words
The system according to claim 1, wherein said signal parameters include at least one of signal strength and signal quality.
Claim 4
Dependent Claim
57 words
The system according to claim 1, wherein said means for determining includes: means for ordering said base stations in accordance with a magnitude of said monitored parameter associated with each of said base stations, and means for selecting a base station as a preferred handoff base station that has the most optimal magnitude of said monitored parameter.
Claim 5
Dependent Claim
68 words
The system according to claim 3, wherein said mobile switching center further comprises: means for determining if a communications channel from said selected base station is available; means for seizing said available communications channel; and means for selecting another base station having the next optimal of said monitored parameter magnitudes if said base station having the most optimal of said monitored parameter magnitudes has no available communications channels.
Claim 6
Dependent Claim
53 words
The system according to claim 1, wherein said mobile switching center includes: means for balancing mobile station communications traffic among said plurality of base stations by handing off call connections associated with serving base stations having higher traffic patterns to neighboring base stations having lower traffic patterns that have initiated a call handoff.
Claim 7
Dependent Claim
60 words
The system according to claim 1, wherein said mobile stations are assigned a priority and said mobile switching center includes: means for granting call connections for mobile stations having higher priority in heavy traffic areas, and means for handing off call connections of lower priority mobile stations in said heavy traffic areas to neighboring base stations in lower traffic areas.
Claim 8
Dependent Claim
65 words
The system according to claim 1, wherein said cellular system includes a plurality of differently sized, geographic areas, each area being associated with a corresponding base station and overlapping with others of said areas, said mobile switching center including: means for handing off mobile stations being served by base stations having large areas to neighboring base stations in smaller areas that overlap said larger areas.
Claim 9
Dependent Claim
33 words
The system according to claim 1, wherein said mobile switching center varies said variable, predetermined threshold of each base station to alter the size of said geographical area corresponding to each base station.
Claim 10
Dependent Claim
17 words
The system according to claim 1, wherein said signal connection is associated with an analog radio channel.
Claim 11
Dependent Claim
17 words
The system according to claim 1, wherein said signal connection is associated with a digital radio channel.
Claim 12
Dependent Claim
159 words
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.
Claim 13
Dependent Claim
159 words
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.
Claim 14
Dependent Claim
46 words
The system according to claim 11, wherein said differently-sized cells include large cells that overlap small cells and said transferring means transfers call connections from a large cell to an overlapped, smaller cell when said detected signal parameter from said smaller cell exceeds a predetermined threshold.
Claim 15
Dependent Claim
15 words
The system according to claim 11, wherein said parameters include signal strength and signal quality.
Claim 16
Dependent Claim
28 words
The system according to claim 11, wherein each cell includes: means for requesting said load balancing means to transfer a currently served call connection to a neighboring cell.
Claim 17
Dependent Claim
47 words
The system according to claim 12, wherein each cell has at least one variable, predetermined threshold and said load balancing means varies the size and shape of at least one cell by changing said at least one variable, predetermined threshold corresponding to said at least one cell.
Claim 18
Dependent Claim
92 words
In a cellular mobile radio telephone system having 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 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 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.
Claim 19
Dependent Claim
92 words
In a cellular mobile radio telephone system having 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 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 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.
Claim 20
Dependent Claim
38 words
The method according to claim 16, wherein said determining step further includes: sequentially ordering said neighboring base stations based on their corresponding detected parameter values, and selecting said preferred base station having the most optimal corresponding parameter value.
Claim 21
Dependent Claim
15 words
The method according to claim 16, wherein said parameter includes signal strength and signal quality.
Claim 22
Dependent Claim
53 words
The method according to claim 16, further comprising: alancing a number of call connections associated with each base station by executing handoffs of call connections associated with congested serving base stations to neighboring base stations which are not congested and which have a detected call connection parameter that satisfies a variable predetermined criterion.
Claim 23
Dependent Claim
17 words
The method according to claim 19, wherein said balancing step further comprises: altering said variable, predetermined criterion.
Claim 24
Dependent Claim
54 words
The method according to claim 16, further comprising: prioritizing subscribers to said cellularsys- tem; granting call connections in high traffic areas to higher priority subscribers; and handing off call connections of lower priority subscribers from said high traffic areas to lower traffic areas in response to call connections granted to said higher priority subscribers.
Claim 25
Dependent Claim
23 words
The method according to claim 16, wherein each pair of neighboring base station and serving base station has at least one associated threshold.
Claim 26
Independent Claim
8 words
The method according to claims 22, further comprising:
Claim 27
Dependent Claim
16 words
varying said at least one associated threshold of said pairs of neighboring and serving base stations.
Claim 28
Dependent Claim
16 words
varying said at least one associated threshold of said pairs of neighboring and serving base stations.
References Cited (Backward Citations)
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