Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-03-19
2001-02-27
Maung, Nay (Department: 2744)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S423000, C455S067150, C455S445000
Reexamination Certificate
active
06195549
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital mobile communication system which is used for public business digital mobile communications and the like.
2. Description of the Prior Art
Recently, information communication technologies have rapidly developed. In particular, mobile communication technology in the radio communication field has remarkably rapidly developed, as has optical communication technology in the wire communication field.
Mobile communications are commonly categorized into commercial communications and non-commercial communications. Among the former communications, there are typically cordless telephones and portable telephones. Among the latter communications, there are typically taxi radio communication, MCA (Multi-Channel Access) land mobile radio communication systems, and public business digital mobile communication systems.
If there arises a disaster, the public business digital mobile communication system considerably serves for transmission of information on the disaster, in contrast with the other communication systems or networks which might malfunction. Accordingly, for communications during a disaster, which are mainly performed by a base station and mobile stations communicating therewith a public business digital mobile communication system, is essential.
Incidentally, in a conventional mobile communication system, e.g., the public business digital mobile communication system, the communication among the mobile stations requires the base station. More specifically, the mobile stations always communicate with each other via the base station, A plurality of base stations are arranged at given distances between them. Each base station has a base station zone to control communication therein. Those base stations are controlled by a control station.
Communication between a mobile station and another mobile station requires a path via two base stations and one control station. For example, there is needed a path like the former mobile station - a first base station - a control station - a second mobile station - the latter base station. Even though the former mobile station and the latter mobile station exit simultaneously in the first base station zone, the communication therebetween requires a path like the former mobile station - the first base station - the control station - the first base station - the latter mobile station. In other words, the control station serves for any communication among any base stations.
In general, base stations are positioned on tops of mountains in order to give larger base station zones, which preferably do not require the presence of any person. In consequence, the base stations require a simple structure immune to a failure or a fault.
In a disaster, however, in the case where there occurs a break in the line between a base station and a control station, even though the base station functions regularly, mobile stations simultaneously positioned within the base stations zone of the base station fail to communicate with each other.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to provide a digital mobile communication system which is capable of elevated reliability.
The present invention relates to a digital mobile communication system in which base station carries out radio communication with a mobile station positioned in the base station zone of one base station and repeats communication between the mobile station and another mobile station positioned in either the base station zone of the base station or the one base station zone of an other base stations via a control station, serving as an upper layer, the system comprising:
a line supervision circuit monitoring a line between the one base station and the control station to prepare a line switch signal for switching the line upon detection of a break in the line; a signal return circuit returning a signal received from the mobile station to radiate the signal over the base station zone of the base one station; and a line switch circuit actuating the signal return circuit in response to the line switch signal.
Another invention relates to a digital mobile communication system as defined above, further comprising a communication circuit radiating the signal received from the mobile station to carry broadcast information to all of the mobile stations over the base station zone of one base station.
Another invention relates to a digital mobile communication system in which a base station carries out radio communication with a mobile station laid in the base station zone of the base station and repeats communication between the mobile station and another mobile station laid in one of the base station zone of the base station and the base station zone of one of other base stations via a control station serving as an upper layer, the system comprising a signal return circuit returning a signal received from the mobile station to radiate the signal over the base station zone of the base station.
And another invention relates to a mobile communication system including a base station handling a signal for communication between a first mobile station and a second mobile station both of which are positioned in the base station zone of the base station, and a control station exchanging the signal with the base station based upon data for managing the communication, the base station comprising:
a receipt circuit receiving the signal from the first mobile station; a transmission circuit transmitting the signal to the control station; a radiation circuit radiating the signal toward the second mobile station;
and a permission/inhibition circuit inhibiting the transmission circuit from transmitting the signal to the control station and permitting the radiation circuit to radiate the signal toward the second mobile station, according to a request.
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PN-3502, “W-CDMA (Wideband Code Division Multiple Acees) Air Interface Compatibility Standard for 1.85 to 1.99 GHz PCS Applications”. Source—TAG-7 (W-CDMA TAG). Distribution—Participants in the Joint Technical Committee Technical Ad Hoc Group No. 7 (TAG-7). Apr. 20, 1995, pp. C-1 through 4-42.
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Gary Erika A.
Maung Nay
OKI Electric Industry Co., Ltd.
Rabin & Champagne, P.C.
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