Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1997-09-09
2001-02-13
Eisenzopf, Reinhard J. (Department: 2745)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S433000
Reexamination Certificate
active
06188911
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to message transmissions between nodes in a mobile telecommunications system, and in particular, to a method and apparatus for eliminating redundant or otherwise unnecessary message transmissions between the nodes.
BACKGROUND OF THE INVENTION
Mobile communications systems, such as cellular radio telephone systems, are typically realized as a network of neighboring radio cells which together provide complete coverage of the area to be serviced. Mobile radio subscribers may roam freely within the area of the system from one cell to another. One well known digital mobile radio system is the Global System for Mobile communication (GSM). Although the present invention is sometimes described using GSM terms, the present invention has wide application, and in any event, applies to any type of cellular or other mobile communications system.
Each cell is served by a base station that includes radio transceiver equipment. Plural base stations are interconnected via a switching node sometimes referred to as a mobile switching center (MSC) which also may be connected to other networks such as the public switched telephone network (PSTN).
Alternatively, several base stations may be controlled by a base station controller (BSC) connected between the base stations and an MSC. Typically, several BSCs are served by a single MSC which controls calls to and from other telephony and data communication networks. Whichever node (MSC or BSC) interconnects a group of base stations, that node controls radio-related functions such as paging, radio channel allocation, hand-over, and power control.
When a call is directed to a mobile station (MS) in the mobile communications system, that mobile station must be located and then paged before a call connection can be established. These tasks are facilitated by having idle mobile stations tuned to a base station control channel and by having the mobile stations periodically transmit registration messages over a base station control channel. As the mobile station moves from cell to cell, it retunes to the current cell's corresponding control channel.
In order to make the location and paging of subscribers efficient, cellular networks are often divided into location areas (LAs) where a location area includes a group of cells. As illustrated in
FIG. 1
, location area
4
(LA
4
) includes cells
1
-
6
. In this example, five location areas LA
1
-LA
5
make up a mobile switching center (MSC) service area. The MSC service area is associated with a visiting location register (VLR) database in which mobile stations currently within that service area are registered. When a call is routed to the MSC, the MSC checks the VLR to identify the current location area in which the called mobile station is registered. Thereafter, a paging message is distributed to those base stations in the identified location area and transmitted by base station transceivers within that location area.
As base station demands increase, the configuration of cells and sharing of equipment becomes more sophisticated. For example,
FIG. 2A
shows a single cell that employs a single omnidirectional antenna commonly used by all of the base station transceivers serving that cell. A more sophisticated configuration is shown in
FIG. 2B
where a single base station site serves three sectors or cells with each such sector cell having its own directional antenna. Each sector cell shares the same pool of transceiving equipment located at the base station site.
Even though the same pool of transceiving equipment is utilized for plural base station sectors, paging messages are sent from the MSC or BSC node to the base station site for each one of the sectors supported at that site. Thus, if the base station services three sectors, three separate but nevertheless identical paging messages are sent from the MSC or BSC to the base station site. This redundant message transmission creates unnecessary signaling, consumes transmission resources, and increases data processing loads. A similar problem exists for other types of control messages sent to some or all base station sectors, e.g., short messaging service (SMS) cell broadcast messages, system information messages used to inform mobile stations regarding network access procedures, etc.
It is an object of the present invention to overcome this problem and eliminate redundant or otherwise unnecessary signaling between nodes in a mobile communications system.
It is also an object of the present invention to minimize processor load associated with sending multiple messages to the same node.
It is a further object of the present invention to provide a single message from the MSC or BSC in a mobile communications system to a base station site and have the base station site transmit that message to multiple sectors supported by that site.
Yet another object of the invention is to improve the speed and performance of mobile radio paging operations.
SUMMARY OF THE INVENTION
The above problems are solved and the above objects are met by this invention. In a mobile radio communications system supporting communications with plural mobile radio units, each of several base stations includes plural radio transceivers and a common controller. The common controller assigns radio channels to ones of the transceivers. A switching controller, e.g., an MSC or BSC, is coupled to the base stations and controls communications involving the radio units. The switching controller transmits a control message, (such as a mobile station paging command, an SMS command, a system information message, etc.), to a selected one (or more) of the base stations. The control message identifies plural channels associated with the selected base station. The common controller in the selected base station distributes the control message to each of the identified channels for radio transmission.
Each channel may correspond for example to one of plural sector cells supported by the base station, e.g., a sector control channel or a sector paging channel. In other words, each sector cell shares the base station radio transceivers under the control of the common controller. Accordingly, the common controller at the base station distributes the control message, which has been transmitted and received only once, so that is transmitted over several channels, e.g., a channel assigned to each sector.
In this way, redundant control messages for each sector need not be transmitted between the switching controller (like an MSC or BSC) and the base station. If the control message is a paging message directed to a mobile radio unit located in an area supported by the base station, only that single paging message is sent from the switching controller to the base station. The paging message is then distributed by the common controller at the base station to each of the paging channels associated with each sector cell supported by the base station.
In different specific embodiments of the present invention, the single control message received by each selected base station from the switch controller indicates that the control message is to be multicast over several channels associated with the selected base station or is to be broadcast over all channels of a specific type associated with the selected base station.
The method of the present invention therefore reduces signaling between a control node and plural base stations by sending a single message from the control node to at least one of the base stations including information that identifies plural communication resources at the one base station rather than separately sending the message to each of the communications resources.
REFERENCES:
patent: 3831095 (1974-08-01), Mounce
patent: 5200954 (1993-04-01), Teel, Jr. et al.
patent: 5239673 (1993-08-01), Natarajan
patent: 5278890 (1994-01-01), Beeson, Jr. et al.
patent: 5436905 (1995-07-01), Li et al.
patent: 5539395 (1996-07-01), Buss et al.
patent: 5570366 (1996-10-01), Baker et al.
patent: 5787357 (1998-07-01), Salin
patent: 5884145 (1999-03-01), Haart
Fredén Anders V. H.
Gustavsson Pär I.
Wallentin Bo S. P.
Bhattacharya Sam
Eisenzopf Reinhard J.
Nixon & Vanderhye P.C.
Telefonaktiebolaget LM Ericsson (publ)
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