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US4803738A Expired / Lapsed US ⏱️ 0.0 years remaining

Radio communications system with reduced D/U ratio variations

Assignee: NEC Corp
•
Filing: 1987-02-09
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Granted: 1989-02-07
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Expires: 2007-02-09
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Abstract

Abstract A radio communications system has a node station centrally located in a covering area and a plurality of remote substations. The system comprises a plurality of transceivers in the node station, and a plurality of substation transceivers respectively located in the substations corresponding respectively to the node station transceivers to establish a plurality of pairs of two-way radio links therebetween. The covering area is divided into a plurality of concentric zones, each of the zones being assigned a pair of particular frequencies or a pair of particular polarization planes. Each zone has one or more substations. Transmission power level of each of the node station transceivers and each of the substation transceivers is adjusted so that fine-weather reception field strength at each end of those radio links having a greater length is greater than fine-weather reception field strength at each end of those radio links having a smaller length, there being a linear relationship between the field stength at each end of each radio link and the length thereof. The minimum azimuth angular spacing between adjacent substations can be reduced by a factor of 1/4 to allow a greater number of substations to be accommodated in the system.

Inventors

  • 👤 Kiyoshi Ikeda

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 07:48
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/24

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 255 words
A radio communications system for covering an area which is divided into "k" concentric zones each being assigned a pair of particular frequencies or polarizations, comprising: a node station located at the center of said area and having a plurality of node station transceivers; and a plurality of substations located in said concentric zones at distance 1 from said node station and at distance 1 k from a boundary between (k-1)th and k-th zones and having a plurality of substation transceivers corresponding respectively to said node station transceivers to establish a plurality of pairs of two-way radio links therebetween, each of said node and substations having a fine-weather reception field strength at each of said radio links, the fine-weather reception field strength at each end of longer distance radio links being greater than the fine-weather reception field strength at each end of shorter distance radio links, there being a linear relationship between said fine-weather reception field strength at each of said radio links and the distance of each link, wherein said linear relationship is given by: ##EQU4## where, RL=fine-weather reception field strength of each of said links at distance 1; RL k =fine-weather reception field strength of each of said links at distance l k ; ML k =difference between the fine-weather reception field strength of each of said links at distance l k and tolerable rainfall reception field strength thereat; and ML.sub.(k-l) =difference between the fine-weather reception field strength of each of said links at distance l.sub.(k-l) and tolerable rainfall reception field strength thereat.
Claim 2
Dependent Claim 255 words
A radio communications system for covering an area which is divided into "k" concentric zones each being assigned a pair of particular frequencies or polarizations, comprising: a node station located at the center of said area and having a plurality of node station transceivers; and a plurality of substations located in said concentric zones at distance 1 from said node station and at distance 1 k from a boundary between (k-1)th and k-th zones and having a plurality of substation transceivers corresponding respectively to said node station transceivers to establish a plurality of pairs of two-way radio links therebetween, each of said node and substations having a fine-weather reception field strength at each of said radio links, the fine-weather reception field strength at each end of longer distance radio links being greater than the fine-weather reception field strength at each end of shorter distance radio links, there being a linear relationship between said fine-weather reception field strength at each of said radio links and the distance of each link, wherein said linear relationship is given by: ##EQU4## where, RL=fine-weather reception field strength of each of said links at distance 1; RL k =fine-weather reception field strength of each of said links at distance l k ; ML k =difference between the fine-weather reception field strength of each of said links at distance l k and tolerable rainfall reception field strength thereat; and ML.sub.(k-l) =difference between the fine-weather reception field strength of each of said links at distance l.sub.(k-l) and tolerable rainfall reception field strength thereat.

References Cited (Backward Citations)

US4004224A Cited
US4301533A Cited
US4383332A Cited
US4412350A Cited
US4495648A Cited
US4613990A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1992-02-07 1992-08-08 1993-02-07 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1996-02-07 1996-08-08 1997-02-07 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2000-02-07 2000-08-08 2001-02-07 $7700.00 Window Closed / Lapsed

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