US 6,549,775 B2Granted

Mobile communication system

AssigneeFujitsu Limited

InventorsKazumasa Ushiki, Mitsunori Fukazawa, Takamitsu Toyoda

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Abstract

A mobile communication system employs narrow paging areas for calling mobile stations without increasing location registration requests to a location management center. This system reduces useless calls and improves the efficiency of use of radio resources. Each local area (1-3) of the system is divided into narrow paging areas (1-4). A storage unit (2-1) is installed in each base station (1-5) or exchange station (1-2), to register mobile stations (1-6). When a base station receives a location registration request from a mobile station, the base station registers the mobile station in the storage unit, and if necessary, transmits a location registration request to the location management center. Upon receiving an incoming call to a mobile station, the exchange station sends an inquiry about the mobile station to the storage units, receives an answer from the storage units, finds a paging area where the mobile station is present from the answer, and issues a call request to base stations that belong to the found paging area.

Claims12

Dependent claims

A mobile communication system, comprising:

a base station having:
storage means installed in the base station, for registering mobile stations in connection with paging areas, the size of which is restricted by dividing the areas covered by at least one base station into a plurality of reduced paging areas, within at least one of which a call to all mobile stations therein is made;
means for receiving a location registration request from a mobile station and for registering the mobile station in the storage means in the base station in connection with a corresponding one of the reduced paging areas;
and
means for determining, according to the location registration request, whether or not a location area or a paging area registered for the mobile station must be updated, if the paging area must be updated, for processing a location registration request within a base station, and if the location area must be updated, for transmitting a location registration request to a location management center through an exchange station;
and
the mobile station includes:
means for comparing (a) a location area identifier and a reduced paging area identifier stored in said mobile station with (b) location area identifier and a reduced paging area identifier transmitted from one of the base stations, and if a difference is detected in at least one of said identifiers, for transmitting to the base station said location registration request containing a mobile station identifier of its own.

5 more elements

A mobile communication system, comprising:

an exchange station having storage means installed in the exchange station, for registering mobile stations in connection with paging areas where the mobile stations are present, means for receiving an incoming call to a mobile station, means for referring to a location management center to find location area registered for the mobile station, means for transmitting an inquiry about the mobile station to the storage means according to the found location area, means for receiving an answer to the inquiry, and identifying one of the paging areas where the mobile station is present according to the answer, and means for transmitting a paging request to base stations that belong to the identified paging area, wherein the paging area are formed in each of the location areas.

Dependencies are inferred from the claim text.