Ntt Docomo, Inc.

Kenji Nishimura

Hiroshi Kawakami

Takashi Koshimizu

Ken Igarashi

Atsushi Iwasaki

Shinichi Isobe

Shoichi Hirata

Shin-ichi Isobe

Masami Yabusaki

Takatoshi Okagawa

Jun Kakishima

A mobile communication systemaccording to the present invention comprises handover control apparatusand radio terminal unit. The handover control apparatuscontrols handover of a radio terminal unitbetween access routers-provided in respective base stations-for radio communication with the radio terminal unit. The handover control apparatuscounts the number of relay routers for every candidate access router-for a destination of the radio terminal unit, from a gateway deviceand determines a COR on the basis of the number of relay routers for every access routerthus counted.

Handover control apparatus, relay router, gateway apparatus, access router, base station, mobile communication system, and handover control method

A communication system includes an MP high-order switching device which determines, for each of a plurality of switching devices, transmission timing at the which the switching device transmits packet data to a plurality of devices connected to the switching device so that data reception timings at a mobile terminal become simultaneous among the plurality of base stations, and a communication section which, in each of the plurality of switching devices, transmits packet data to the plurality of devices connected to the switching device, based on the determined transmission timing corresponding to the switching device.

Communication system, multicast switching device, and communication method

A mobile communication system of the present invention includes a handover control unit and a packet transfer network, which are independent of each other. The handover control unit selects a handover control system in accordance with a QoS. The handover control unit issues an instruction to the packet transfer network in accordance with the selected handover control system.

Controlling handover between different packet networks by using common primitive messages to manage QoS

Rerouting of packet exchanges by a mobile terminal is controlled so as to be optimized on a real time basis to prevent network resources from being wasted by redundant routing. In an initial state a route of data from a mobile communication terminal M to a CN, which is a communication partner, is a route R. Then, an access router (AR)acquires the number of hops of data received from the CNby the mobile communication terminal M. As the mobile communication terminal M now performs a handover to under the command of the AR, the route will change to a route R. Then the ARdetects that the route becomes redundant by the fact that the number of hops acquired after the shift is greater than the pre-shift number of hops received from the AR, and invokes control to reroute to a route R, which provides the optimal routing.

Method, terminal and router for detection of trigger to rerouting

Handover control apparatus, relay router, gateway apparatus, access router base station, mobile communication system, and handover control method

A radio data communications method capable of changing control points located in a network without causing loss of data when a mobile terminal is performing a soft handover. In the radio data communications method in which at least one of a first radio network controller and a second radio network controller performs a soft handover process for allowing a soft handover of a mobile terminal when the mobile terminal is performing soft handover, in downlink radio data communications in which the first radio network controller transmits data to a mobile terminal via a second radio network controller and a base station (or in uplink radio data communications). The first radio network controller or the second radio network controller performing the soft handover process is changed when the mobile terminal is performing the soft handover.

Radio data communications method, server, and radio network controller

In a mobile communication network comprised of a plurality of switching devices and a plurality of base stations connected to the switching devices, while a mobile terminal to wirelessly communicate with the base stations is in a communication by a soft handover, a terminal endpoint of a protocol for control of the soft handover is relocated in changing a switching device to another as a branch/combining point of data on a communication route of the communication.

Growing community of inventors

Yokosuka, Japan

Kenji Nishimura