Radio communications system with reduced D/U ratio variations

• US 4,803,738 A
• Filed: 02/09/1987
• Issued: 02/07/1989
• Est. Priority Date: 02/10/1986
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ikeda, Kiyoshi
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Kuntz, Curtis A.
• Application Number:
  US07/012,227
• Time in Patent Office: 729 Days
• Field of Search: 455/33, 455/52, 455/73, 455/83, 455/67, 455/10, 455/9, 455/53, 455/54, 379/59, 379/60
• US Class Current: 455/10
• CPC Class Codes: H04B 7/24 for communication between two or more posts wireless communication networks H04W

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.

Claims

1. 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.