Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2000-10-11
2004-08-03
Kincaid, Lester G. (Department: 2686)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S444000, C455S422100, C455S432200, C455S450000
Reexamination Certificate
active
06771968
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
Not Applicable.
BACKGROUND
1. Technical Field
The claimed invention relates generally to telecommunications. More particularly, the claimed invention relates to a system, method and apparatus for interference protection in a telecommunications system.
2. Description of Related Art
Generally, wireless office systems (WOS) and more particularly digital wireless office systems (D-WOS) are well known in the art. Such wireless office systems can either stand-alone or are adjuncts to private-branch exchanges (PBXs). (WOS and D-WOS will be referred to as WOS hereinafter.) A PBX is a private telephone switch serving several extensions for establishing end-to-end connectivity among users, supervising the communication circuit and tearing down a communication path upon terminating or disconnecting a call. The PBX system is generally used as a corporate voice network within one building or several buildings situated on a campus. Communications are generally handled between users within the PBX system or between the PBX system and the public switched telephone network (PSTN) including mobile telephone wireless networks.
The WOS converts a PBX extension into a mobile phone extension such that a user with a mobile telephone can carry on communications with the mobile telephone. Accordingly, the WOS performs communication hand-offs between general-purpose mobile wireless communication networks (the macro-network hereinafter) and the WOS (and vice-versa) while the user moves about into and out of the building or campus that houses the PBX system. The user also can use the mobile telephone over a limited outdoor campus area, for example. However, because the WOS operates on wireless communication principles, there is an inherent tendency for such systems to interfere with the macro-network because the WOS can use the same frequencies, or channels, as ones that are allocated to the macro-network.
Generally, the WOS uses frequencies on the wireless frequency spectrum that are unused. A wireless office scanner is used to select a communication channel from the unused frequencies on the wireless spectrum. The scanner scans for frequencies that are used by the macro-network and deems such frequencies as unusable by the WOS. However, although the scanners are employed in order to prevent interference with the macro-network, in the event that the scanner should fail, the channels that were deemed unusable by the scanner would be put back in service. In other words, related art WOSs rely on the operation of the scanner to continuously provide a useable frequency spectrum to the WOSs. Accordingly, in a WOS deployment there exists the potential for interference by the WOS to the macro-network if the same frequencies are used by the WOS and the macro-network. Therefore, in the event the scanner becomes defective and fails to scan for local frequencies being used by the macro-network, the WOS will reuse any available frequencies. Related art methods, systems and apparatuses provide some protection by manually removing certain channels from use by the WOS. However, the manual process is labor intensive and, with the introduction of automated channel allocation (ACA), the manual process becomes increasingly more difficult and impractical to use.
Therefore, there is a need to provide a method; system and apparatus to mitigate the potential interference to the macro-network in the event of a catastrophic failure of a WOS scanner. Furthermore, there also is a need to provide a method, system and apparatus to communicate between a WOS and a macro-network for gathering information about macro-network channel reuse within a geographic area in proximity of a building or campus utilizing a WOS. Such information would be useful in determining which frequencies are being used by the macro-network and then removing such frequencies from service so as not to be used by the WOS.
SUMMARY
In accordance with the claimed invention the limitations of the related art described above and other limitations that will become apparent upon reading and understanding the present specification are overcome by providing a system, method and apparatus for eliminating interference in a first network in the event of a failure that occurs in a second network. The method, system and apparatus in accordance with one embodiment of the claimed invention provide an added level of first network interference protection in a second network environment by removing certain frequencies/channels of the first network from being utilized by the second network. In one embodiment, for example, the frequencies/channels identified by a scanner associated with the second network during the scanning process that are allocated to the first network are removed from the pool of available frequencies/channels that can be utilized by the second network, and such frequencies/channels are stored in a table.
One aspect of the claimed invention provides a method of preventing interference to a first network by a second network. The method includes identifying frequencies being used by the first network; storing the identified frequencies in a table; and barring the identified frequencies from being used by the second network.
Another aspect of the claimed invention provides a method of providing interference protection to a first wireless network in a second wireless network, the first wireless network including one or more cells having one or more cell sites associated therewith and the second wireless network including a scanner and a controller. The method includes identifying a first frequency associated with each one or more individual cells of the first wireless network; identifying a code associated with one or more of the individual cells; formulating a query in accordance with the identified first frequency and the code; transmitting the query from the first wireless network to a switching device associated with the first wireless network; the switching device responding to the query and transmitting one or more values of frequencies allocated to a cell associated with the first network as identified by the query; storing the one or more values of frequencies allocated to the first wireless network in a table; and barring the frequencies allocated to the first wireless network from being used by the second wireless network.
Yet another aspect of the invention provides a method of processing a telephone call between a first wireless network and a second wireless network. The method includes creating a table of frequencies allocated to the first network; and barring the frequencies stored in the table from being used by the second wireless network.
Still another aspect of the claimed invention provides a method of exchanging information between first and second wireless networks, the first network including one or more cells, a gateway and a telecommunication switch and the second network including a scanner and a controller. The method includes scanning the one or more cells for cell identifying information; providing the cell identifying information to the telecommunication switch; receiving by the controller, information pertaining to the identified cell; and storing the information pertaining to the identified cell in a table.
A further aspect of the claimed invention provides a system for preventing interference to a first network by a second network. The system includes a scanner; a controller in communication with the scanner; and a memory device coupled to the controller having a table stored therein, the table having frequencies stored therein that are allocated for use by the first network; wherein, the controller retrieves the frequencies stored in the table and bars the allocated frequencies from being used by the second network.
Still a further aspect of the claimed provides a wireless office system having an apparatus for preventing interference to a macro-network by the wireless office. The apparatus includes a scanner; a controller in communication with the scanner; and a memory
BellSouth Intellectual Property Corporation
Iqbal K
Kincaid Lester G.
Kirkpatrick & Lockhart LLP
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