Mobile communication system, radio switching method, mobile base station and mobile terminal
First Claim
1. A mobile communication system comprising:
- a plurality of fixed base stations that are serially disposed along a moving direction of a moving body capable of high-speed moving and that are connected to a public telephone network;
a mobile terminal that is possessed by a user who gets on the moving body; and
a mobile base station that is capable of being connected to the plural fixed base stations and that is put in or on the moving body, wherein;
triggered by an entrance of the mobile terminal into a first communication area of the mobile base station and by a start of the moving body, the mobile terminal performs a first handover from one of the fixed base stations that has been connected to the mobile terminal to the mobile base station;
while the moving body is moving, the mobile base station initiates and sequentially performs a second handover to an adjacent one of the fixed base stations when the moving body enters into a second communication area of the adjacent one of the fixed base stations; and
when the moving body approaches a stop, the mobile terminal initiates a third handover from the mobile base station to another of the fixed base stations that covers a third communication area around the stop, so that the mobile terminal communicates directly with the another of the fixed base stations and does not communicate via the mobile base station,wherein the mobile base station is separate and distinct from the mobile terminal.
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Accused Products
Abstract
A mobile communication system, a radio switching method, a mobile base station and a mobile terminal in which the mobile terminal does not perform handover to a fixed base station while moving in/on a moving body to avert an adverse affect of variation of received field intensity on communication. Fixed base stations that are connected to a public telephone network are disposed along a traveling direction of a train. The train which a user who possesses a mobile terminal gets on is provided with a mobile base station capable of being connected to the fixed base stations. The mobile base station detects the mobile terminal entering into the communication area covered by the mobile base station and the train starting moving to the next station. Triggered by the two kinds of detection, the mobile base station takes over processes of handover to the fixed base station from the mobile terminal. While moving, the mobile base station performs handover to a next base station one after another. When the train approaches the next station, the mobile terminal performs handover to the fixed base station that covers the communication area around the station of arrival in behalf of the mobile base station.
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Citations
20 Claims
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1. A mobile communication system comprising:
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a plurality of fixed base stations that are serially disposed along a moving direction of a moving body capable of high-speed moving and that are connected to a public telephone network; a mobile terminal that is possessed by a user who gets on the moving body; and a mobile base station that is capable of being connected to the plural fixed base stations and that is put in or on the moving body, wherein; triggered by an entrance of the mobile terminal into a first communication area of the mobile base station and by a start of the moving body, the mobile terminal performs a first handover from one of the fixed base stations that has been connected to the mobile terminal to the mobile base station; while the moving body is moving, the mobile base station initiates and sequentially performs a second handover to an adjacent one of the fixed base stations when the moving body enters into a second communication area of the adjacent one of the fixed base stations; and when the moving body approaches a stop, the mobile terminal initiates a third handover from the mobile base station to another of the fixed base stations that covers a third communication area around the stop, so that the mobile terminal communicates directly with the another of the fixed base stations and does not communicate via the mobile base station, wherein the mobile base station is separate and distinct from the mobile terminal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A radio switching method for sequentially performing handover to an adjacent fixed base station among a plurality of fixed base stations that covers respective communication areas divided into cells according to a move of a mobile terminal, comprising the steps of:
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performing, by the mobile terminal in or on a moving body, a first handover from one of the fixed base stations that covers a first communication area where the moving body is located to a mobile base station that is put in or on the moving body, which is triggered by an entrance of the mobile terminal possessed by a user into a second communication area of the mobile base station and when the moving body starts moving; initiating and sequentially performing, by the mobile base station, a second handover to an adjacent one of the fixed base stations when the moving body enters into a third communication area of the adjacent one of the fixed base stations while the moving body is moving; and initiating, by the mobile terminal, a third handover from the mobile base station to another of the fixed base stations that covers a fourth communication area around a stop when the moving body approaches the stop, so that the mobile terminal communicates directly with the another of the fixed base stations and does not communicate via the mobile base station, wherein the mobile base station is separate and distinct from the mobile terminal. - View Dependent Claims (8, 9, 10, 11)
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12. A mobile base station that is put in or on a moving body, comprising:
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a first detecting means for detecting a mobile terminal entering into a first communication area of the mobile base station; a second detecting means for detecting the moving body which a user of the mobile terminal gets on starting moving; and a control means for; connecting to the mobile terminal and to a first fixed base station that has been connected to the mobile terminal to continue communication between the mobile terminal and the first fixed base station on the basis of the detection by the first and the second detecting means; performing, by the mobile terminal upon entrance of the mobile terminal into the first communication area of the mobile base station and upon a start of the moving body, a first handover from the first fixed base station that has been connected to the mobile terminal to the mobile base station; performing a second handover, upon receiving an external signal sent from another device, to a second fixed base station when the moving body enters into a second communication area of the second fixed base station while the moving body is moving; and getting the mobile terminal to initiate a third handover to a third fixed base station that covers a third communication area around a stop when the moving body approaches the stop, so that the mobile terminal communicates directly with the another of the fixed base stations and does not communicate via the mobile base station, wherein the mobile base station is separate and distinct from the mobile terminal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A mobile terminal capable of communicating with a fixed base station connected to a public telephone network by radio, including a communication means capable of communicating with a mobile base station put in or on a moving body when the mobile terminal is in or on or in the vicinity of the moving body, wherein:
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the mobile terminal communicates with the mobile base station while the mobile terminal is moving in or on the moving body; and the mobile terminal initiates a first handover from the mobile base station to a fixed base station that covers a communication area around a stop when the moving body approaches the stop, so that the mobile terminal communicates directly with the fixed base station that covers a communication area around a stop and does not communicate via the mobile base station, wherein the mobile terminal performs, upon of the mobile terminal into a first communication area of the mobile base station and upon a start of the moving body, a second handover from the fixed base station that has been connected to the mobile terminal to the mobile base station, wherein the mobile terminal does not initiate handover from the mobile base station when the moving body is not approaching the stop and the mobile terminal moves from a cell of a first base station to a cell of a second base station, wherein the mobile base station is separate and distinct from the mobile terminal, and wherein the mobile base station is capable of assisting in handover for a plurality of mobile terminals including the mobile terminal. - View Dependent Claims (19, 20)
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Specification