EP0360589A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Cellular data communications system
Assignee: Cellular Data Inc
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Filing: 1989-09-20
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Granted: —
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Expires: 2009-09-20
Abstract
Abstract In a cellular data transmission system non-interfering digital communication channels are added to existing analog or digital voice communications channels in the system by utilising frequency space between channels made possible by the co-channel and adjacent channel frequency co-ordination procedures. Interference is prevented by reduction of power, selection of frequencies, proper modulation and demodulation techniques, and unique allocation to the channels in frequency and location. The system is also applicable in general to the insertion of narrow frequency bandwidth channels in any existing communications system using co-channel and adjacent channel frequency allocation strategies.
Inventors
- 👤 Bruce Lusignan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 10:28
CPC Classifications
H; H04; H04W; H04W16/00; H04W16/14; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2621; H04W52/00; H04W52/04; H04W16/02; H04W16/12; H04W16/24; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
201 words
A cellular data communications system having a plurality of contiguous cells each with a cell site having a radio transceiver with voice and setup channels for communicating with mobile units within the cell, each of said standard voice and setup channels having a predetermined frequency bandwidth, a predetermined portion of said channels for each cell having alternate non-used channels between used channels to provide adequate adjacent channel separation while information is being transmitted on a used channel at a predetermined power level, a plurality of said cells being grouped in a cluster to provide a number of disjoint channel sets, characterised by additional data channels for carrying digital data, including means for transmitting said digital data to and from at least one field unit in a cell and said cell site, concurrently with information on a said used channel, each said additional channel having a frequency centered substantially midway between said used and unused channels. of the same or adjacent cell and including means for transmitting on said additional channels at a power at least an order of magnitude lower than said predetermined power level and for controlling bandwith spreading of said additional channels to prevent interference with adjacent used channels.
Claim 2
Dependent Claim
201 words
A cellular data communications system having a plurality of contiguous cells each with a cell site having a radio transceiver with voice and setup channels for communicating with mobile units within the cell, each of said standard voice and setup channels having a predetermined frequency bandwidth, a predetermined portion of said channels for each cell having alternate non-used channels between used channels to provide adequate adjacent channel separation while information is being transmitted on a used channel at a predetermined power level, a plurality of said cells being grouped in a cluster to provide a number of disjoint channel sets, characterised by additional data channels for carrying digital data, including means for transmitting said digital data to and from at least one field unit in a cell and said cell site, concurrently with information on a said used channel, each said additional channel having a frequency centered substantially midway between said used and unused channels. of the same or adjacent cell and including means for transmitting on said additional channels at a power at least an order of magnitude lower than said predetermined power level and for controlling bandwith spreading of said additional channels to prevent interference with adjacent used channels.
Claim 3
Dependent Claim
99 words
A system as claimed in Claim 1, characterised in that said radio transceiver of a said cell site has a transmit bandwidth greater than said standard channel bandwidth, at low power levels, and a receiver bandwidth narrower than a said channel bandwidth, said transmit bandwidth of one channel intersecting with the receiver bandwidth of an adjacent channel in another cell, said adjacent channel having a predetermined receive threshold level, but below said receive threshold level, said frequency centering of said additional channel providing an intersection of its bandwidth at or below said intersection of said transmit and receiver bandwidth.
Claim 4
Dependent Claim
28 words
A system as claimed in Claim 1 or Claim 2, characterised in that said means for controlling bandwidth spreading includes modulation means of the minimum shift keying type.
Claim 5
Independent Claim
23 words
A system as claimed in any preceding claim, characterised in that said field unit includes a directional antenna aimed at said cell site.
Claim 6
Independent Claim
38 words
A system as claimed in any preceding claim, characterised in that said predetermined frequency bandwidth is 30 kHz and said additional channels have a frequency offset form the centre of a said used channel of substantially 115 kHz.
Claim 7
Independent Claim
19 words
A system as claimed in any preceding claim, characterised in that the gain of said field unit is adjustable.
Claim 8
Dependent Claim
160 words
A communications system having a central radio transmitter and receiver site for simultaneously communicating with a plurality of field units over a plurality of standard channels, comprising means for transmitting information on additional channels to and from a plurality of additional field units and said central site, concurrently with information on said standard channels, said additional channels having a frequency offset from said standard channels, said transmitting means including minimum shift keying modulation and demodulation means for minimising bandwidth spreading, said central site including precision frequency generating means, said field units including means for utilising said precision generating means as a frequency reference for such field unit, and means included in said central site and said additional field units for time division multiplexing over a single additional channel, for carrying data at a predetermined data rate, responses from a plurality of additional field units to said central site to minimise the data rate of said single channel and its bandwith.
Claim 9
Dependent Claim
160 words
A communications system having a central radio transmitter and receiver site for simultaneously communicating with a plurality of field units over a plurality of standard channels, comprising means for transmitting information on additional channels to and from a plurality of additional field units and said central site, concurrently with information on said standard channels, said additional channels having a frequency offset from said standard channels, said transmitting means including minimum shift keying modulation and demodulation means for minimising bandwidth spreading, said central site including precision frequency generating means, said field units including means for utilising said precision generating means as a frequency reference for such field unit, and means included in said central site and said additional field units for time division multiplexing over a single additional channel, for carrying data at a predetermined data rate, responses from a plurality of additional field units to said central site to minimise the data rate of said single channel and its bandwith.
Claim 10
Dependent Claim
29 words
A system as claimed in Claim 7, characterised in that said means for time division multiplexing includes adjustable storage register means in said field units for providing non-conflicting responses.
Claim 11
Dependent Claim
18 words
A system as claimed in Claim 8, characterised in that said responses are substantially of one bit width.
Claim 12
Independent Claim
34 words
A system as claimed in any one of Claims 7 to 9, characterised in that said system is cellular, said central site is a cell site, and said field units are within a cell.
Claim 13
Independent Claim
60 words
A system as claimed in any preceding claim, characterised in that adjacent channel and co-channel interference is avoided and frequency re-use is provided by geographical placement of cells in a cluster having adjacent channels in different cells with at least one intervening cell between them and channels of the same frequency separated by at least one intervening cell between them.
Claim 14
Independent Claim
55 words
A system as claimed in any one of Claims 1 to 10, which is an advanced mobile phone service system, characterised in that adjacent channel and co-channel interference is avoided and frequency re-use is provided by use of directional antennas with adjacent channels in respectively adjacent cells being isolated by the directionality of said antennas.
References Cited (Backward Citations)
No citation records indexed.
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