EP0421698A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of predicting cell-to-cell hand-offs for a satellite cellular communications system
Assignee: Motorola Solutions Inc
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Filing: 1990-10-01
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Granted: —
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Expires: 2010-10-01
Abstract
Abstract A method of predicting cell-to-cell hand-offs of mobile subscribers (22) for a satellite cellular communications system. Each satellite (10) of a constellation projects a number of beams or cells (20,26) upon the earth for communication with mobile subscribers. The satellite (10) transfers (hand-offs) communications links from cell to cell as the satellite moves over the mobile subscriber. Since the movement of the satellite is stabilized in three directions, the projection of the beams or cells (24,26,28) follows a predictable path across the face of the earth. Each satellite moves across the earth in one direction. Once a subscriber is located within one cell (24), the next cell (26) to which the mobile subscriber is handed-off may be determined from the geographic position. For mobile users which are close to boundaries between cells, additional position location may be determined by the calculation of bit error rates (50-68). The results of these bit error rate measurements then indicate the identity of the cell which is to receive the hand-off of the mobile user.
Inventors
- 👤 Bary Robert Bertiger
- 👤 Kenneth Maynard Peterson
- 👤 Raymond Joseph Leopold
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 02:30
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1853; H04B7/18539; H04B7/18541; H04B7/204; H04B7/2041; H04W; H04W36/00; H04W36/08; H04W36/083; H04W24/00; H04W24/10; H04W64/00; H04W84/00; H04W84/02; H04W84/04; H04W84/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
136 words
A method of predicting cell-to-cell hand-offs of a mobile subscriber (22) for a satellite communication system, said satellite (10) including a plurality of cells, each cell (30) for facilitating communication with said subscriber, and a processor for executing said method of predicting cell-to-cell hand-offs, said satellite being in orbit about, the earth, said method of predicting cell-to-cell hand-offs of a mobile subscriber for a satellite cellular communication system comprising the steps of: determining (54-56) the position of said mobile subscriber as being within a first cell of said satellite; selecting (58-66) a second cell of said satellite, said second cell being in a direction of movement of said satellite as the next cell to be positioned over said mobile subscriber; and executing (68) said hand-off of said subscriber from said first cell to said second cell.
Claim 2
Independent Claim
136 words
A method of predicting cell-to-cell hand-offs of a mobile subscriber (22) for a satellite communication system, said satellite (10) including a plurality of cells, each cell (30) for facilitating communication with said subscriber, and a processor for executing said method of predicting cell-to-cell hand-offs, said satellite being in orbit about, the earth, said method of predicting cell-to-cell hand-offs of a mobile subscriber for a satellite cellular communication system comprising the steps of: determining (54-56) the position of said mobile subscriber as being within a first cell of said satellite; selecting (58-66) a second cell of said satellite, said second cell being in a direction of movement of said satellite as the next cell to be positioned over said mobile subscriber; and executing (68) said hand-off of said subscriber from said first cell to said second cell.
Claim 3
Dependent Claim
71 words
A method of predicting cell-to-cell hand-offs as claimed in claim 1, wherein there is further including the steps of: second determining (52,58) a bit error rate for transmissions by said mobile subscriber for a predetermined number of said cells; second selecting (64) a second cell based upon the value of said bit error rates; and second executing (68) said hand-off of said subscriber from said first cell to said second cell.
Claim 4
Dependent Claim
37 words
A method of predicting cell-to-cell hand-offs as claimed in claim 2, wherein said step of second selecting includes the step of finding (62) a bit error rate which is a minimum value of said bit error rates.
Claim 5
Dependent Claim
47 words
A method of predicting cell-to-cell hand-offs as claimed in claim 3, wherein said step of second determining further includes the steps of : calculating (52,58) said bit error rate of said messages; and determining (60) whether said bit error rate is less than a predetermined threshold value.
Claim 6
Dependent Claim
64 words
A method of predicting cell-to-cell hand-offs as claimed in claim 4, wherein said step of second selecting includes the steps of: third selecting (66) said second cell as being in the direction of movement of said satellite, if said bit error rate is less than said threshold value; and executing (68) said hand-off of said subscriber from said first cell to said second cell.
Claim 7
Dependent Claim
41 words
A method of predicting cell-to-cell hand-offs as claimed in claim 5, wherein said step of second selecting further includes the step of eighth determining (64) a boundary of said first cell which is closest to said location of said mobile subscriber.
Claim 8
Dependent Claim
60 words
A method of predicting cell-to-cell hand-offs as claimed in claim 6, wherein there is further included the steps of: first predicting (66) a second cell based upon said determination of said boundary which is closest to said mobile subscriber's location; and second predicting (66) a time at which to perform said hand-off from said first cell to said second cell.
Claim 9
Dependent Claim
49 words
A method of predicting cell-to-cell hand-offs as claimed in claim 7, wherein said step of executing includes the step of performing (68) said hand-off from said first cell to said second cell at said predicted time in order to maintain continuous communication with said mobile subscriber by said satellite.
Claim 10
Dependent Claim
35 words
A method of predicting cell-to-cell hand-offs as claimed in claim 1, wherein there is further included the step of finding (64) a direction of movement of said orbiting satellite with respect to said mobile subscriber.
References Cited (Backward Citations)
No citation records indexed.
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