Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-08-25
2001-06-05
Hunter, Daniel (Department: 2749)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S524000
Reexamination Certificate
active
06243575
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to mobile communication and, particularly, to a mobile communication system involving a mobile base station that is installed in, for example, a train to provide value-added services to mobile units such as cellular phones and pagers that are present in a mobile space formed in the train. The present invention also relates to a method of controlling such a system and such a mobile base station.
The present invention allocates a mobile radio zone to a mobile space defined in, for example, a public transport unit such as a train or a bus, and provides specific services only to mobile units that are present in the mobile radio zone.
2. Description of the Related Art
There are no prior arts that employ the concept of assigning a mobile radio zone to a mobile space so that the mobile radio zone may travel together with the mobile space. This concept is advantageous in clearly separating the inside of the mobile space from the outside thereof.
The prior arts employ fixed radio zones, which are unable to separate subscriber terminals that are present in the mobile space from those that are present outside the mobile space. The prior arts, therefore, are unable to provide exclusive services only to subscriber terminals that are present in the mobile space.
FIG. 1
shows a mobile communication system according to a prior art.
An existing base station
10
(A) has a fixed radio zone
20
(CzA) in which a mobile space
30
(B) travels. The mobile space
30
accommodates mobile subscriber terminals
40
and
41
(a, b). A mobile subscriber terminal
42
(c) is inside the zone
20
but outside the mobile space
30
. The existing base station
10
provides communication services to the subscriber terminals
40
to
42
.
The existing base station
10
directly controls the subscriber terminals
40
to
42
with regard to their call and speech signals and, therefore, cannot know whether the subscriber terminal
40
is inside or outside the mobile space
30
. The existing base station
10
simply provides the same services to all of the subscriber terminals
40
to
42
without discriminating the subscriber terminals
40
and
41
that are inside the mobile space
30
from the subscriber terminal
42
that is outside the same.
If the mobile space
30
wants to provide the inside thereof with specific services such as arrival time notification, the mobile space
30
must have devices to display the information, or passengers in the mobile space
30
must have special receivers to receive the information. Such display devices involve costs, which may be absorbed by displaying corporate advertisements thereon. The costs of such special receivers, however, must impose a burden on passengers.
Instead of the special receivers, the existing base station
10
may employ standard subscriber terminals to use special dial services. The mobile space
30
, however, travels along a route where there are radio blocking objects such as high buildings and tunnels. It is impossible for the existing base station
10
to secure stable communication for the subscriber terminals in the mobile space
30
that travels along such a radio blocking route.
When the mobile space
30
moves from the zone
20
to the next zone
21
at a high speed, channel switching and position registering processes simultaneously occur between the existing base stations and the subscriber terminals in the mobile space
30
, to maintain communication between them. This may temporarily congest a network that connects the existing base stations to one another. At the same time, each subscriber terminal must scan perch channels to exhaust the battery thereof.
SUMMARY OF THE INVENTION
An object of the present invention is to assign at least one mobile radio zone to a mobile space such as a train or a bus so that the mobile radio zone may travel with the mobile space. The mobile radio zone clearly separates the inside of the mobile space from the outside thereof and provides subscriber terminals that are present in the mobile radio zone with exclusive services.
In order to accomplish the object, the present invention provides a mobile communication system including existing base stations each for controlling a fixed radio zone that covers a predetermined area, a mobile base station for controlling at least one mobile radio zone assigned to a mobile space, and mobile subscriber terminals.
The mobile base station has a first communication unit for communicating with the existing base stations, a second communication unit for communicating with the subscriber terminals, and a control unit for controlling path connection between the first and second communication units.
The first communication unit connects and switches channels to the existing base stations, independently of the second communication unit. The first communication unit holds control channels to the existing base stations and scans perches sequentially for released ones of the control channels.
The second communication unit connects and switches channels to the subscriber terminals, independently of the first communication unit. The number of mobile radio zones controlled by the second communication unit is at least one, and the second communication unit communicates with subscriber terminals that are present in the mobile radio zones.
The second communication unit makes the level of signals transmitted thereby higher than the level of signals received thereby from the existing base stations.
The mobile base station further has a service unit for providing specific services to subscriber terminals that are present in the mobile radio zones. The specific services may be individually provided to the mobile radio zones.
When entering into and exiting from the mobile radio zone, a subscriber terminal according to the present invention connects and switches channels if the entered or exited state continues for a predetermined time. The mobile base station may confirm the entered or exited state according to whether or not the state continues for the predetermined time. The existing base stations may confirm the entered or exited state according to whether or not the state continues for the predetermined time.
REFERENCES:
patent: 5519761 (1996-05-01), Gilhousen
patent: 5659882 (1997-08-01), Fukutomi
patent: 5867785 (1999-02-01), Averbuch et al.
patent: 58-63242 (1983-04-01), None
patent: 62-101135 (1987-05-01), None
Ohyama Kazuya
Takahashi Takenari
Armstrong Darnell R.
Fujitsu Limited
Helgott & Karas P C
Hunter Daniel
LandOfFree
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