Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-07-14
2001-03-06
Le, Thanh Cong (Department: 2684)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S435100, C455S445000, C455S554100, C455S560000
Reexamination Certificate
active
06198932
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a controller for use with a radiocommunications system which controls a plurality of base stations connected to mobile telephones via a radio channel within a business establishment, and more particularly, to a control operation for the purpose of allocating control slots to the base stations, respectively.
2. Description of the Related Art
FIG. 6
is a block diagram showing an existing radiocommunications system used in a business establishment, wherein a PBX (private branch exchange) main unit
1
is connected to a plurality of base stations
2
and to a personal computer PC
3
used for customizing the PBX
1
.
The PBX main unit
1
comprises a PBX control section
11
for controlling the overall PBX main unit
1
, a control slot frequency management section
12
which manages the frequency of a control slot assigned to each of the base stations
2
, a control slot period management section
13
for managing a period of the control slot during which a radio frequency signal is transmitted from the base station
2
, a base station interface
14
which serves as an interface between the PBX main unit
1
and the base stations
2
, a PC interface
15
which serves as an interface between the PBX unit
1
and the PC
3
, and a broadcast call area number management section
16
which manages a broadcast call area number registered for the purpose of preventing the positions of mobile stations from being registered in the adjacent base stations
2
in an overlapping manner.
Each of the base stations
2
comprises a PBX interface
21
which serves as an interface between the PBX main unit
1
and the base station
1
, a base station control section
22
for controlling the entire base station
2
, a control slot management section
23
which stores the frequency and period of the control slot assigned to each of the base stations
2
, and a radio section
24
which emits a radio frequency signal.
At the time of designing of the base stations, with regard to the adjacent base stations
2
, the PC
3
sets an identical broadcast call area number in the broadcast call area number management sections
16
by way of the PC interface
15
. In a case where a mobile station is handed over from one zone to another zone of the base stations
2
assigned the same broadcast call area number, the position of the mobile station is not registered in the base station.
The PBX control section
11
allocates control slots to the base stations
2
in numerical order of ports of the PBX main unit
1
and thus-allocated control slots are stored in the control slot frequency management section
12
and the control slot period management section
13
. Details of allocation of the control slots are stored in the control slot management section
23
of each base station
2
by way of the base station interface
14
and the PBX interface
21
. Depending on the settings of the control slot management section
23
, each base station
2
determines the frequency and period of the control slot during which a radio frequency signal is transmitted from the base station
2
.
FIG. 7
is a table showing broadcast call area numbers respectively assigned to base stations CS
1
to CS
8
, frequencies (i.e., the details of the control slot frequency management section
12
) f
1
and f
2
, periods (i.e., details of the control slot period management section
13
) “a”-“d” of the respective control slots, and control slots A through H.
FIG. 8
is a schematic representation showing the control slots A to H allocated respectively to the four periods “a” to “d” during one cycle of control channels of two frequencies f
1
and f
2
.
FIG. 7
shows base stations CS
1
and CS
2
assigned the same broadcast call area number, i.e., 1, and base stations CS
5
and CS
6
assigned the same broadcast call area number, i.e., 4. The base stations assigned the same broadcast area number are positioned in close proximity to each other. Other base stations CS
3
, CS
4
, CS
7
, and CS
8
are not positioned in close proximity to one another, and hence they are respectively assigned individual broadcast call area numbers 2, 3, 5, and 6.
The base stations CS
1
to CS
4
are allocated a control channel of frequency f
1
, and the base stations CS
5
to CS
8
are allocated a control channel of frequency f
2
. The base stations CS
1
to CS
4
are respectively sequentially assigned the four periods “a” to “d” into which one cycle of the control channel of frequency f
1
is divided. Similarly, the base stations CS
5
to CS
8
are sequentially and respectively assigned the four periods “a” to “d” into which one cycle of the control signal of frequency f
2
is divided. Consequently, as shown in
FIG. 8
, the base stations CS
1
to CS
4
are respectively allocated the control slots A to D, and the base stations CS
5
to CS
8
are respectively allocated the control slots E to H.
If existing radiocommunications systems are provided in close proximity to each other, and if control slots which one of the systems attempts to use have already been used by the other system, it becomes impossible for the former system to control mobile stations existing in a service area covered by base stations of the former system.
FIG. 9
shows a schematic layout showing an example of the adjacent radiocommunications systems and their base stations. Base stations CS
1
, CS
2
, and CS
3
are connected to one PBX main unit
1
A. Base stations CSa and CSb are connected to another PBX main unit B. In this example, the base stations CS
1
, CS
2
, and CSa are positioned in close proximity to one another. In this layout, the rate of connection between the mobile station and the base station CS
1
or CS
2
is decreased by interference from the base station CSa.
SUMMARY OF THE INVENTION
The present invention has been conceived to solve the aforementioned drawback in the prior art, and an object of the present invention is to provide a controller for use with a radiocommunications system which prevents a decrease in the rate of connection among mobile stations and base stations of the system, which would otherwise be caused by interference resulting from another adjacent radiocommunications system using the same frequency band as that of the system.
To achieve the above object, a controller for use with a radiocommunications system according to the present invention, comprises:
a control slot frequency management section which manages the frequency of a control slot allocated to each of base stations;
a broadcast call area number management section which manages broadcast call area numbers registered for the purpose of preventing the position of a mobile station from being registered in the adjacent base stations; and
a control slot frequency allocation section which sets the details of the control slot frequency management section in such a way that control channels of different frequencies are allocated to a plurality of base stations assigned the same broadcast area number.
The present invention is capable of providing a controller for use with a radiocommunications system which prevents a decrease in the rate of connection among mobile stations and base stations of the system, which would otherwise be caused by interference from another adjacent radiocommunications system which uses the same frequency band as that of the system.
A first aspect of the present application is directed to a controller for use with a radiocommunications system which controls a plurality of base stations connected to mobile stations by way of radio channels, the controller comprising:
a control slot frequency management section which manages the frequency of a control slot assigned to each of the base stations;
a broadcast call area number management section which manages broadcast call area numbers registered for the purpose of preventing the positions of the mobile stations from being registered in the adjacent base stations in an overlapping manner; and
a control slot frequency allocation section which sets the deta
Cong Le Thanh
Matsushita Electric - Industrial Co., Ltd.
Nguyen Thuan T.
Pearne & Gordon LLP
LandOfFree
Controller for use with a radiocommunications system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Controller for use with a radiocommunications system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Controller for use with a radiocommunications system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2457679