Mobile communication system, mobile terminal, and mobile communication method
First Claim
1. A mobile communication system comprising:
- a multicast router which receives an information signal addressed to a predetermined multicast group transmitted from a transmitter and which can make a copy of the received information signal and can distribute it to a network downstream thereof when a mobile terminal belonging to the multicast group is present downstream of the router;
a data link layer switch which receives the information signal distributed from the multicast router and which can distribute a copy of the received information signal only to a multicast distribution path in which a mobile terminal belonging to the multicast group is present;
a radio base station which is connected to the data link layer switch and which can distribute the information signal distributed by the data link layer switch to a radio network downstream thereof; and
a mobile terminal which receives the information signal distributed by the radio base station, the mobile terminal comprising;
station switching detection means which detects that the radio base station connected to the terminal itself has been switched;
router switching detection means which detects that the multicast router connected to the terminal itself has been switched;
establishment request transmission means which transmits a path establishing request for requesting at least the data link layer switch to establish a multicast distribution path for distributing the information signal to the radio base station connected to the terminal itself;
withdrawal request transmission means which transmits a withdrawal request for requesting at least the multicast router to withdraw from the multicast group to which the mobile terminal itself belongs; and
transmission control means which transmits a first instruction signal for instructing the establishment request transmission means to transmit the path establishing request and a second instruction signal for instructing the withdrawal request transmission means to transmit the withdrawal request, depending on the detection by the station switching detection means, wherein;
when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, the transmission control means sequentially outputs the first instruction signal, the second instruction signal, and the first instruction signal again; and
when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the transmission control means outputs the first instruction signal to transmit the path establishing request to the new multicast router and thereafter outputs the second instruction signal to transmit the withdrawal request to the previous multicast router.
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Accused Products
Abstract
It is an object of the present invention to provide a mobile communication system capable of shortening a delay time preceding the reception of a multicast packet at a radio base station which has been reached by a movement of a mobile terminal. The mobile communication system includes a multicast router, a data layer link switch, a radio base station, and a mobile terminal. In cases where the mobile terminal detects switching of the radio base station but does not detect switching of the multicast router, a path establishing request, a withdrawal request, and another path establishing request are sequentially output. When the switching of the radio base station and the switching of the multicast router is detected, a path establishing request is transmitted to the new multicast router, and a withdrawal request is transmitted to the previous multicast router thereafter.
27 Citations
10 Claims
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1. A mobile communication system comprising:
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a multicast router which receives an information signal addressed to a predetermined multicast group transmitted from a transmitter and which can make a copy of the received information signal and can distribute it to a network downstream thereof when a mobile terminal belonging to the multicast group is present downstream of the router;
a data link layer switch which receives the information signal distributed from the multicast router and which can distribute a copy of the received information signal only to a multicast distribution path in which a mobile terminal belonging to the multicast group is present;
a radio base station which is connected to the data link layer switch and which can distribute the information signal distributed by the data link layer switch to a radio network downstream thereof; and
a mobile terminal which receives the information signal distributed by the radio base station, the mobile terminal comprising;
station switching detection means which detects that the radio base station connected to the terminal itself has been switched;
router switching detection means which detects that the multicast router connected to the terminal itself has been switched;
establishment request transmission means which transmits a path establishing request for requesting at least the data link layer switch to establish a multicast distribution path for distributing the information signal to the radio base station connected to the terminal itself;
withdrawal request transmission means which transmits a withdrawal request for requesting at least the multicast router to withdraw from the multicast group to which the mobile terminal itself belongs; and
transmission control means which transmits a first instruction signal for instructing the establishment request transmission means to transmit the path establishing request and a second instruction signal for instructing the withdrawal request transmission means to transmit the withdrawal request, depending on the detection by the station switching detection means, wherein;
when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, the transmission control means sequentially outputs the first instruction signal, the second instruction signal, and the first instruction signal again; and
when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the transmission control means outputs the first instruction signal to transmit the path establishing request to the new multicast router and thereafter outputs the second instruction signal to transmit the withdrawal request to the previous multicast router. - View Dependent Claims (2)
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3. A mobile terminal belonging to a multicast group and receiving an information signal transmitted on a multicast bases through a multicast router, a data link layer switch, and a radio base station, comprising:
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station switching detection means which detects that the radio base station connected to the terminal itself has been switched;
router switching detection means which detects that the multicast router connected to the mobile terminal itself has been switched;
establishment request transmission means which transmits a path establishing request for requesting at least the data link layer switch to establish a multicast distribution path for distributing an information signal to the radio base station connected to the mobile terminal itself;
withdrawal request transmission means which transmits a withdrawal request for requesting at least the multicast router to withdraw from the multicast group connected to the mobile terminal itself, to which the terminal belongs; and
transmission control means which transmits a first instruction signal for instructing the establishment request transmission means to transmit the path establishing request and a second instruction signal for instructing the withdrawal request transmission means to transmit the withdrawal request, in response to the, detection by the station switching detection means, wherein;
when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, the transmission control means sequentially outputs the first instruction signal, the second instruction signal, and the first instruction signal again; and
when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the transmission control means outputs the first instruction signal to transmit the path establishing request to the new multicast router and thereafter outputs the second instruction signal to transmit the withdrawal request to the previous multicast router.
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4. A mobile communication method for a mobile terminal belonging to a multicast group to receive an information signal transmitted on a multicast bases through a multicast router, a data link layer switch, and a radio base station, the method comprising:
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a station switching detection step at which station switching detection means of the mobile terminal detects that the radio base station connected to the mobile terminal itself has been switched;
a router switching detection step at which router switching detection means of the mobile terminal detects that the multicast router connected to the mobile terminal itself has been switched;
a first updating step at which, when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, establishment request transmission means of the mobile terminal transmits a path establishing request for requesting the data link layer switch to establish a path for distributing an information signal to the radio base station connected to the mobile terminal itself, at which withdrawal request transmission means of the mobile terminal successively transmits a withdrawal request for requesting the multicast router to withdraw from the multicast group to which the mobile terminal itself belongs, and at which the establishment, request transmission means transmits the path establishing request; and
a second updating step at which, when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the establishment request means transmits the path establishing request to the new multicast router, and the withdrawal request transmission means transmits the withdrawal request to the previous multicast router.
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5. A mobile communication system comprising:
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a multicast router which receives an information signal addressed to a predetermined multicast group transmitted from a transmitter and which can make a copy of the received information signal and can distribute it to a network downstream thereof when a mobile terminal belonging to the multicast group is present downstream of the router;
a data link layer switch which receives the information signal distributed by the multicast router and which can distribute a copy of the received information signal only to a multicast distribution path in which a mobile terminal belonging to the multicast group is present;
a radio base station which is connected to the data link layer switch and which can distribute the information signal distributed by the data link layer switch to a radio network downstream thereof; and
a mobile terminal which receives the information signal distributed by the radio base station, the mobile terminal comprising;
station switching detection means which detects that the radio base station connected to the mobile terminal itself has been switched;
router switching detection means which detects that the multicast router connected to the mobile terminal itself has been switched;
establishment request transmission means which transmits a path establishing request for requesting at least the data link layer switch to establish a multicast distribution path for distributing the information signal to the radio base station connected to the mobile terminal itself;
withdrawal request transmission means which transmits a withdrawal request for requesting at least the multicast router to withdraw from the multicast group to which the mobile terminal itself belongs; and
transmission control means which transmits a first instruction signal for instructing the establishment request transmission means to transmit the path establishing request and a second instruction signal for instructing the withdrawal request transmission means to transmit the withdrawal request, in response to the detection by the station switching detection means and the router switching detection means, wherein;
when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, the transmission control means sequentially outputs the first instruction signal, the second instruction signal, and the first instruction signal again; and
when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the transmission control means outputs the first instruction signal to transmit the path establishing request to the new multicast router and thereafter sequentially outputs the second instruction signal and the first instruction signal to transmit the withdrawal request and the path establishing request to the previous multicast router. - View Dependent Claims (6)
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7. A mobile terminal belonging to a multicast group and receiving an information signal transmitted on a multicast bases through a multicast router, a data link layer switch, and a radio base station, comprising:
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station switching detection means which detects that the radio base station connected to the mobile terminal itself has been switched;
router switching detection means which detects that the multicast router connected to the mobile terminal itself has been switched;
establishment request transmission means which transmits a path establishing request for requesting at least the data link layer switch to establish a multicast distribution path for distributing an information signal to the radio base station connected to the mobile terminal itself;
withdrawal request transmission means which transmits a withdrawal request for requesting at least the multicast router to withdraw from the multicast group connected to the mobile station itself, to which the terminal belongs; and
transmission control means which transmits a first instruction signal for instructing the establishment request transmission means to transmit the path establishing request and a second instruction signal for instructing the withdrawal request transmission means to transmit the withdrawal request, in response to the detection by the station switching detection means and the router switching detection means, wherein;
when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, the transmission control means sequentially outputs the first instruction signal, the second instruction signal, and the first instruction signal again; and
when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the transmission control means outputs the first instruction signal to transmit the path establishing request to the new multicast router and thereafter sequentially outputs the second instruction signal and the first instruction signal to transmit the withdrawal request and the path establishing request to the previous multicast router. - View Dependent Claims (8)
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9. A mobile communication method for a mobile terminal belonging to a multicast group to receive an information signal transmitted on a multicast bases through a multicast router, a data link layer switch, and a radio base station, the method comprising:
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a station switching detection step at which station switching detection means of the mobile terminal detects that the radio base station connected to the mobile terminal itself has been switched;
a router switching detection step at which router switching detection means of the mobile terminal detects that the multicast router connected to the mobile terminal itself has been switched;
a third updating step at which, when the station switching detection means detects the switching of the radio base station but the router switching detection means does not detect the switching of the multicast router, establishment request transmission means of the mobile terminal transmits a path establishing request for requesting the data link layer switch to establish a path for distributing an information signal to the radio base station connected to the mobile terminal itself, at which withdrawal request transmission means of the mobile terminal successively transmits a withdrawal request for requesting the multicast router to withdraw from the multicast group to which the mobile terminal itself belongs, and at which the establishment request transmission means transmits the path establishing request; and
a fourth updating step at which, when the station switching detection means detects the switching of the radio base station and the router switching detection means detects the switching of the multicast router, the establishment request means transmits the path establishing request to the new multicast router, at which the withdrawal request transmission means successively transmits the withdrawal request to the previous multicast router, and at which the establishment request transmission means further transmits the path establishing request to the previous multicast router thereafter. - View Dependent Claims (10)
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Specification