Ntt Mobile Communications Network, Inc.

Akiko Nakashima

Motoshi Tamura

Tomoyuki Ohtani

Takaaki Satoh

Hisashi Shimizu

Katsuhiko Yamagata

Mutsumaru Miki

Akira Kaiyama

Disclosed is a mobile communication system including a network constituted of at least one switching center and a plurality of base stations, and a mobile station which communicates with the base stations simultaneously. The system permits varying transmission delay between the switching center and the base stations according to the type of services available to the mobile station. The object of the present invention is to propose a communication which permits varying transmission delay according to the type of service currently employed, and to promptly recover a synchronization state even if an out-of-sync state happens. To attain the object, a memory means (mobile switching center processor ) stores transmission delay characteristics corresponding to services which are available to the mobile station. Furthermore, a communication timing setting means (diversity handover trunk ) determines the timing of communication for the base stations according to the transmission delay characteristic selected according to the service.

Method for handover

A mobile communication system which is capable of supporting multiple simultaneous communications on a single mobile terminal device, and collectively controlling all or a part of call states on a mobile terminal device. The system includes at least one mobile terminal device having: more than one mobile terminal side call control units for controlling calls at a mobile terminal side; and a mobile terminal side mobile terminal management unit for managing a communication state of the mobile terminal device while identifying each mobile terminal side call control unit which is currently in communication. The system also includes a network device having: a plurality of network side call control units for controlling calls at a network side; and a network side mobile terminal management unit, provided in correspondence to the mobile terminal device, for managing the communication state of the mobile terminal device and correspondences between said plurality of network side call control units and the mobile terminal device while identifying each network side call control unit which is currently in communication.

Mobile communication system for supporting multiple simultaneous communications on single mobile terminal

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Kokubunji, Japan

Akiko Nakashima