US4862453A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Communication system
Assignee: BAE Systems Electronics Ltd
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Filing: 1987-10-02
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Granted: 1989-08-29
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Expires: 2007-10-02
Abstract
Abstract In a dynamic frame length slotted ALOHA system the synchronizing signals are transmitted by a base station at different frequencies (each having a period equivalent to a multiple of the time slot period). The different frequencies denote different frame lengths and the central stations detect these frequencies and select a frame length accordingly.
Inventors
- 👤 Barry G. West
- 👤 Boleslaw M. Sosin
- 👤 Roger K. Tolfree
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:50
CPC Classifications
H; H04; H04W; H04W28/00; H04W28/02; H04W28/06; H04W56/00; H04W74/00; H04W74/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
107 words
A communication system comprising: a central station (1) having means (5,3) for transmitting synchronizing signals each defining the beginning of a time slot and means (4) for selecting the intervals between synchronising signals from different integral multiples of a time slot and for providing to said transmitting means signals corresponding to said intervals; and a number of sub-stations (6,61) each having means (10,11,12) which is responsive to the timing of the synchronising signals and which is operative to transmit a message in a time slot selected from a number of time slots together forming a frame, the duration of said frame being determined by said synchronizing signals.
Claim 2
Dependent Claim
107 words
A communication system comprising: a central station (1) having means (5,3) for transmitting synchronizing signals each defining the beginning of a time slot and means (4) for selecting the intervals between synchronising signals from different integral multiples of a time slot and for providing to said transmitting means signals corresponding to said intervals; and a number of sub-stations (6,61) each having means (10,11,12) which is responsive to the timing of the synchronising signals and which is operative to transmit a message in a time slot selected from a number of time slots together forming a frame, the duration of said frame being determined by said synchronizing signals.
Claim 3
Dependent Claim
28 words
A communication system according to claim 1 in which the means responsive to the timing of the synchronising signal measures a time interval between two adjacent synchronising signals.
Claim 4
Dependent Claim
29 words
A communication system according to claim 2 in which the said number of time slots defines a "frame" of a length which is different from the said time interval.
Claim 5
Dependent Claim
83 words
A central station for a communication system which also includes a number of sub-stations, the central station comprising means for transmitting to each sub-station synchronising signals each defining the beginning of a time slot and means, responsive to the observed occupancy of time slots by signals received from the sub-stations, for selecting, in accordance with a predetermined algorithm, the intervals between the synchronising signals from different multiples of a time slot and for transmitting signals corresponding to said intervals to said transmitting means.
Claim 6
Dependent Claim
83 words
A central station for a communication system which also includes a number of sub-stations, the central station comprising means for transmitting to each sub-station synchronising signals each defining the beginning of a time slot and means, responsive to the observed occupancy of time slots by signals received from the sub-stations, for selecting, in accordance with a predetermined algorithm, the intervals between the synchronising signals from different multiples of a time slot and for transmitting signals corresponding to said intervals to said transmitting means.
Claim 7
Dependent Claim
74 words
A sub-station for a communications system which comprises a central station according to claim 4 and at least one other sub-station, the sub-station comprising means which is responsive to the timing of synchronising signals received from the central station to determine the number of equal-length time slots to be allocated to a variable-length frame, and which is operative to transmit a message to the central station within a time slot selected from the frame.
Claim 8
Dependent Claim
27 words
A sub-station according to claim 5 in which the means responsive to the timing of the synchronising signal measures a time interval between two adjacent synchronising signals.
Claim 9
Dependent Claim
28 words
A sub-station according to claim 6 in which the said number of time slots defines a "frame" of a length which is different from the said time interval.
References Cited (Backward Citations)
US3602647A
Cited
US4160877A
Cited
US4398289A
Cited
US4583221A
Cited
US4612637A
Cited
US4648090A
Cited
US4686673A
Cited
US4653049A
Cited
GB2166929A
Cited
US4782484A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |