US 5,845,209 AGranted

Mobile communications system

AssigneeFujitsu Limited

InventorYasuharu Iwata

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Abstract

A mobile radio communications system which keeps operational even when the signal reception conditions deteriorate due to interference. Mobile stations in the system communicate through radio communication channels via a base station. A plurality of interference monitor stations are fixedly placed in the service zone of the base station. The interference monitor stations, being wired to the base station via telecommunications lines, constantly monitors transmission signals sent from the base station. A reception condition monitoring unit watches the reception conditions of the transmission signals to detect interference. If any interference is detected, an interference detection signal output unit sends an interference detection signal to the base station via the telecommunications lines. Upon reception of the interference detection signal, a carrier switching controller forces a carrier of the transmission signal to be switched to another carrier after confirming predefined conditions.

Claims8

Dependent claims

A mobile communications system in which mobile stations communicate through radio transmission channels, comprising:

a service coverage area including first clusters and second clusters, each of the first and second clusters consisting of at least three service zones to which different carriers are uniquely allocated, whereby a limited number of carriers are reused in distant regions within the service coverage area;
a base station, disposed in each service zone, which communicate with the mobile stations by using a carrier that is allocated to said each service zone,
a plurality of interference monitor stations, disposed in each service zone, for detecting interference affecting the carrier assigned to said each service zone;
and
carrier switching control means, coupled to said plurality of interference monitor stations and activated when the interference is detected in a particular service zone that belongs to one of the first clusters, for directing the base station disposed in said particular service zone to change the carrier under the interference to another carrier being allocated to another service zone which belongs to one of the second clusters and does not overlap with said particular service zone.

2 more elements

Dependencies are inferred from the claim text.