Patent US5285447A successfully refreshed from Google Patents.
US5285447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Target channel verification in a radiotelephone system
Assignee: Motorola Solutions Inc
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Filing: 1993-04-23
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Granted: 1994-02-08
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Expires: 2013-04-23
Abstract
Abstract A radiotelephone system verifies the carrier/interference (C/I) of a selected target channel before handoff. The subscriber (125), communicating to a source base-station (130) on a source channel, measures the received signal strength indication (RSSI) of a target channel at a target base-station (135) when the channel is keyed (transmitting) and dekeyed (not transmitting). The subscriber (125) transfers the measurements to a source base-station (130) which determines the ratio of the RSSI with the keyed channel (C) to the RSSI with the dekeyed channel (I). If the ratio is greater than a predetermined threshold, the source base-station (130) transfers the subscriber (125) from the source channel to the target channel at the target base-station (135).
Inventors
- 👤 Thomas G. Hulsebosch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:02
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/24; H04W36/30; H04W36/302; H04W36/0005; H04W36/0055; H04W36/0058; H04W36/08; H04W36/34; H04W36/38
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
146 words
A radiotelephone system having target channel verification before communication transfer, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station coupled to a plurality of target base-stations, the radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels and for transmitting on a target channel; a subscriber unit for measuring first signal quality values of said transmissions on said plurality of signalling channels and a second signal quality value of said transmission on said target channel; and a source base-station for selecting one of said plurality of target base-stations to transmit on said target channel based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to the target channel when said second signal quality value is greater than a transfer threshold.
Claim 2
Dependent Claim
146 words
A radiotelephone system having target channel verification before communication transfer, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station coupled to a plurality of target base-stations, the radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels and for transmitting on a target channel; a subscriber unit for measuring first signal quality values of said transmissions on said plurality of signalling channels and a second signal quality value of said transmission on said target channel; and a source base-station for selecting one of said plurality of target base-stations to transmit on said target channel based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to the target channel when said second signal quality value is greater than a transfer threshold.
Claim 3
Dependent Claim
18 words
The radiotelephone system of claim 1 wherein said target channel is a new source channel after communication transfer.
Claim 4
Dependent Claim
29 words
The radiotelephone system of claim 1 wherein said subscriber unit for measuring a first signal quality value further comprises a subscriber unit for measuring a first signal strength value.
Claim 5
Dependent Claim
35 words
The radiotelephone system of claim 1 wherein said source base-station for selecting further comprises a source base-station having a hysteresis value correlating the physical location of said source base-station to each of said target base-stations.
Claim 6
Dependent Claim
45 words
The radiotelephone system of claim 4 wherein said source base-station for selecting further comprises a source base-station which adds said first signal quality values of said transmissions on said plurality of signalling channels to each corresponding hysteresis value to produce first modified signal quality values.
Claim 7
Dependent Claim
30 words
The radiotelephone system of claim 5 wherein said source base-station for selecting further comprises a source base-station for selecting said target base-station based on said first modified signal quality values.
Claim 8
Dependent Claim
55 words
The radiotelephone system of claim 4 wherein said source base-station for transferring communication further comprises a source base-station for transferring communication of the subscriber unit from the source channel to the target channel when said second signal quality value plus a hysteresis value corresponding to the selected target base-station is greater than said transfer threshold.
Claim 9
Dependent Claim
205 words
A radiotelephone system having target channel verification before communication transfer, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels and for transmitting on a target channel; a subscriber unit for measuring a first signal quality value of said transmissions on said plurality of signalling channels, for measuring a second signal quality value in the absence of a transmission on said target channel to produce an interference measurement (I), and for measuring a third signal quality value of a transmission on said target channel to produce a carrier measurement (C); and a source base-station for selecting one of said plurality of target base-stations to transmit based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than a transfer threshold.
Claim 10
Dependent Claim
205 words
A radiotelephone system having target channel verification before communication transfer, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels and for transmitting on a target channel; a subscriber unit for measuring a first signal quality value of said transmissions on said plurality of signalling channels, for measuring a second signal quality value in the absence of a transmission on said target channel to produce an interference measurement (I), and for measuring a third signal quality value of a transmission on said target channel to produce a carrier measurement (C); and a source base-station for selecting one of said plurality of target base-stations to transmit based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than a transfer threshold.
Claim 11
Dependent Claim
18 words
The radiotelephone system of claim 8 wherein said target channel is a new source channel after communication transfer.
Claim 12
Dependent Claim
29 words
The radiotelephone system of claim 8 wherein said subscriber unit for measuring a first signal quality value further comprises a subscriber unit for measuring a first signal strength value.
Claim 13
Dependent Claim
35 words
The radiotelephone system of claim 8 wherein said source base-station for selecting further comprises a source base-station having a hysteresis value correlating the physical location of said source base-station to each of said target base-stations.
Claim 14
Dependent Claim
45 words
The radiotelephone system of claim 11 wherein said source base-station for selecting further comprises a source base-station which adds said first signal quality values of said transmissions on said plurality of signalling channels to each corresponding hysteresis value to produce first modified signal quality values.
Claim 15
Dependent Claim
30 words
The radiotelephone system of claim 12 wherein said source base-station for selecting further comprises a source base-station for selecting said target base-station based on said first modified signal quality values.
Claim 16
Dependent Claim
66 words
The radiotelephone system of claim 11 wherein said source base-station for transferring communication further comprises a source base-station for transferring communication of the subscriber unit from the source channel to the target channel when the ratio of said measured third signal quality value to said measured second signal quality value, plus a hysteresis value corresponding to the selected target base-station, is greater than said transfer threshold.
Claim 17
Dependent Claim
283 words
A time-division multiple access (TDMA) radiotelephone system having target channel verification before communication transfer, the TDMA radiotelephone system having a source base-station communicating with a subscriber unit on a source channel during at least one of a plurality of TDMA timeslots, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the TDMA radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels during one of a plurality of TDMA timeslots and for transmitting on a target channel during a second one of said plurality of TDMA timeslots; a subscriber unit for measuring a first signal quality value of said transmissions on said plurality of signalling channels during at least one of a plurality of TDMA timeslots, for measuring a second signal quality value in the absence of a transmission of said target channel during said second one of said plurality of TDMA timeslots to produce an interference measurement (i), and for measuring a third signal quality value of a transmission of said target channel during said second one of said plurality of TDMA timeslots to produce a carrier measurement (C); and a source base-station for selecting one of said plurality of target base-stations to transmit on said target channel during said second one of said plurality of TDMA timeslots based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than a transfer threshold.
Claim 18
Dependent Claim
283 words
A time-division multiple access (TDMA) radiotelephone system having target channel verification before communication transfer, the TDMA radiotelephone system having a source base-station communicating with a subscriber unit on a source channel during at least one of a plurality of TDMA timeslots, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the TDMA radiotelephone system comprising: a plurality of target base-stations for transmitting on a plurality of signalling channels during one of a plurality of TDMA timeslots and for transmitting on a target channel during a second one of said plurality of TDMA timeslots; a subscriber unit for measuring a first signal quality value of said transmissions on said plurality of signalling channels during at least one of a plurality of TDMA timeslots, for measuring a second signal quality value in the absence of a transmission of said target channel during said second one of said plurality of TDMA timeslots to produce an interference measurement (i), and for measuring a third signal quality value of a transmission of said target channel during said second one of said plurality of TDMA timeslots to produce a carrier measurement (C); and a source base-station for selecting one of said plurality of target base-stations to transmit on said target channel during said second one of said plurality of TDMA timeslots based on said first signal quality value measurement, and for transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than a transfer threshold.
Claim 19
Dependent Claim
30 words
The TDMA radiotelephone system of claim 15 wherein said subscriber unit for measuring a first signal quality value further comprises a subscriber unit for measuring a first signal strength value.
Claim 20
Dependent Claim
36 words
The TDMA radiotelephone system of claim 15 wherein said source base-station for selecting further comprises a source base-station having a hysteresis value correlating the physical location of said source base-station to each of said target base-stations.
Claim 21
Dependent Claim
46 words
The TDMA radiotelephone system of claim 17 wherein said source base-station for selecting further comprises a source base-station which adds said first signal quality values of said transmissions on said plurality of signalling channels to each corresponding hysteresis value to produce first modified signal quality values.
Claim 22
Dependent Claim
31 words
The TDMA radiotelephone system of claim 18 wherein said source base-station for selecting further comprises a source base-station for selecting said target base-station based on said first modified signal quality values.
Claim 23
Dependent Claim
67 words
The TDMA radiotelephone system of claim 17 wherein said source base-station for transferring communication further comprises a source base-station for transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said measured third signal quality value to said measured second signal quality value, plus a hysteresis value corresponding to the selected target base-station, is greater than said transfer threshold.
Claim 24
Independent Claim
230 words
A method of verifying a target channel before communication transfer in a radiotelephone system, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the method comprising the steps of: transmitting, at a plurality of target base-stations, on a plurality of signalling channels; measuring, at the subscriber unit, a first signal quality value of said transmissions on said plurality of signalling channels; selecting, at the source base-station, one of said plurality of target base-stations based on an optimum first signal quality value measurement; transmitting, at the selected target base-station, on a target channel; measuring, at the subscriber unit, a second signal quality value in the absence of said transmission on a target channel to produce an interference measurement (I); measuring, at the subscriber unit, a third signal quality value of said transmission on said target channel to produce a carrier measurement (C); providing, at the source base-station, a target channel quality transfer threshold; and transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than said target channel quality transfer threshold.
Claim 25
Independent Claim
230 words
A method of verifying a target channel before communication transfer in a radiotelephone system, the radiotelephone system having a source base-station communicating with a subscriber unit on a source channel, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the method comprising the steps of: transmitting, at a plurality of target base-stations, on a plurality of signalling channels; measuring, at the subscriber unit, a first signal quality value of said transmissions on said plurality of signalling channels; selecting, at the source base-station, one of said plurality of target base-stations based on an optimum first signal quality value measurement; transmitting, at the selected target base-station, on a target channel; measuring, at the subscriber unit, a second signal quality value in the absence of said transmission on a target channel to produce an interference measurement (I); measuring, at the subscriber unit, a third signal quality value of said transmission on said target channel to produce a carrier measurement (C); providing, at the source base-station, a target channel quality transfer threshold; and transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than said target channel quality transfer threshold.
Claim 26
Dependent Claim
37 words
The radiotelephone system of claim 21 wherein said first target channel is a signalling channel and wherein said step of measuring a first signal quality value further comprises the step of measuring a first signal strength value.
Claim 27
Dependent Claim
32 words
The radiotelephone system of claim 21 wherein said step of selecting further comprises the step of providing a hysteresis value correlating the physical location of the source base-station to said target base-station.
Claim 28
Dependent Claim
43 words
The radiotelephone system of claim 23 wherein said step of selecting further comprises the step of adding said first signal quality value of said transmission on at least a first channel to said hysteresis value to produce a first modified signal quality value.
Claim 29
Dependent Claim
30 words
The radiotelephone system of claim 24 wherein said step of selecting further comprises the step of selecting said target base-station when an optimum first modified signal quality value is produced.
Claim 30
Dependent Claim
62 words
The radiotelephone system of claim 23 wherein said step of transferring communication further comprises the step of transferring communication of the subscriber unit from the source channel to the second target channel when the ratio of said measured third signal quality value to said measured second signal quality value, plus said hysteresis value, is greater than said target channel quality transfer threshold.
Claim 31
Independent Claim
308 words
A method of verifying a target channel before communication transfer in a time-division multiple access (TDMA) radiotelephone system, the TDMA radiotelephone system having a source base-station communicating with a subscriber unit on a source channel during at least one of a plurality of TDMA timeslots, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the method comprising the steps of: transmitting, at a plurality of target base-stations, on a plurality of signalling channels during at least one of a plurality of TDMA timeslots; measuring, at the subscriber unit, a first signal quality value of said transmissions on said plurality of signalling channels during at least one of a plurality of TDMA timeslots; selecting, at the source base-station, one of said plurality of target base-stations based on an optimum first signal quality value measurement; transmitting, at the selected target base-station, on a target channel during at least a second one of said plurality of TDMA timeslots; determining, at the subscriber unit, which of said remaining TDMA timeslots on said target channel is unoccupied; measuring, at the subscriber unit, at least a second signal quality value in the absence of said transmission on said target channel to produce an interference measurement (I); measuring, at the subscriber unit and responsive to said step of determining, a third signal quality value of said transmission on said target channel during an unoccupied TDMA timeslot to produce a carrier measurement (C); providing, at the source base-station, a target channel quality transfer threshold; and transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than said target channel quality transfer threshold.
Claim 32
Independent Claim
308 words
A method of verifying a target channel before communication transfer in a time-division multiple access (TDMA) radiotelephone system, the TDMA radiotelephone system having a source base-station communicating with a subscriber unit on a source channel during at least one of a plurality of TDMA timeslots, the source base-station located within a first coverage area and coupled to a plurality of target base-stations via a base-station interface, the plurality of target base-stations located within a corresponding plurality of coverage areas, the method comprising the steps of: transmitting, at a plurality of target base-stations, on a plurality of signalling channels during at least one of a plurality of TDMA timeslots; measuring, at the subscriber unit, a first signal quality value of said transmissions on said plurality of signalling channels during at least one of a plurality of TDMA timeslots; selecting, at the source base-station, one of said plurality of target base-stations based on an optimum first signal quality value measurement; transmitting, at the selected target base-station, on a target channel during at least a second one of said plurality of TDMA timeslots; determining, at the subscriber unit, which of said remaining TDMA timeslots on said target channel is unoccupied; measuring, at the subscriber unit, at least a second signal quality value in the absence of said transmission on said target channel to produce an interference measurement (I); measuring, at the subscriber unit and responsive to said step of determining, a third signal quality value of said transmission on said target channel during an unoccupied TDMA timeslot to produce a carrier measurement (C); providing, at the source base-station, a target channel quality transfer threshold; and transferring communication of the subscriber unit from the source channel to said target channel when the ratio of said carrier measurement (C) to said interference measurement (I) is greater than said target channel quality transfer threshold.
Claim 33
Dependent Claim
28 words
The TDMA radiotelephone system of claim 27 wherein said step of measuring a first signal quality value further comprises the step of measuring a first signal strength value.
Claim 34
Dependent Claim
33 words
The TDMA radiotelephone system of claim 27 wherein said step of selecting further comprises the step of providing a hysteresis value correlating the physical location of the source base-station to said target base-station.
Claim 35
Dependent Claim
44 words
The TDMA radiotelephone system of claim 29 wherein said step of selecting further comprises the step of adding said first signal quality value of said transmission on at least a first channel to said hysteresis value to produce a first modified signal quality value.
Claim 36
Dependent Claim
31 words
The TDMA radiotelephone system of claim 30 wherein said step of selecting further comprises the step of selecting said target base-station when an optimum first modified signal quality value is produced.
Claim 37
Dependent Claim
66 words
The TDMA radiotelephone system of claim 29 wherein said step of transferring communication further comprises the step of transferring communication of the subscriber unit from the source channel to said at least a first target channel when the ratio of said measured third signal quality value to said measured second signal quality value, plus said hysteresis value, is greater than said target channel quality transfer threshold.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1997-02-07 | 1997-08-09 | 1998-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-07 | 2001-08-09 | 2002-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-07 | 2005-08-09 | 2006-02-08 | $7700.00 | Window Closed / Lapsed |