Multiplex communications – Communication over free space – Having a plurality of contiguous regions served by...
Reexamination Certificate
1997-12-31
2001-06-05
Hsu, Alpus H. (Department: 2662)
Multiplex communications
Communication over free space
Having a plurality of contiguous regions served by...
C370S335000, C370S338000, C455S422100, C709S203000
Reexamination Certificate
active
06243367
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to communication networks and, more specifically, to a wireless telephone network employing variable power transmitters.
BACKGROUND OF THE INVENTION
In 1996, more than 75 million people worldwide used cellular telephones. Reliable predictions indicate that there will be over 300 million cellular telephone customers by the year 2000. Within the United States, cellular service is offered not only by dedicated cellular service providers, but also by the regional Bell companies, such as U.S. West, Bell Atlantic and Southwestern Bell, and the national long distance companies, such as AT&T and Sprint. The enhanced competition has driven the price of cellular service down to the point where it is affordable to a large segment of the population.
This competition has also led to a rapid and sweeping innovation in cellular telephone technology. Analog cellular systems are now competing with digital cellular systems. Older frequency division multiple access (FDMA) and time division multiple access (TDMA) systems are now competing with code division multiple access (CDMA) systems. In order to maximize the number of subscribers that can be serviced in a single cellular system, frequency reuse is maximized by making individual cell sites smaller and using a greater number of cell sites to cover the same geographical area. In a typical system upgrade, several existing adjacent cell site are subdivided into multiple smaller sites having different frequency assignments. Care is taken to maximize the distance between cells using the same frequency range. Each of the smaller cell sites may be further subdivided by use of a sectored antenna that splits the cell site into, for example, three 120 degree sectors. The multi-sector, multi-frequency architecture greatly increases the number of users that can be served.
Accordingly, the increased number of base transceiver stations and/or sectored antennas has resulted in increased infrastructure costs. To offset this increased cost, cellular service providers are eager to implement any innovations that may reduce equipment costs, maintenance/repair costs, and operating costs, or that may increase service quality/reliability, and the number of subscribers that the cellular system can service. Much of this innovation has focused on service quality improvements, such as expanded digital PCS services, on user equipment improvements, such as smaller and lighter cellular phone handsets having a longer battery life, or on infrastructure cost reduction, such as smaller, cheaper, more reliable transceivers for the cellular base stations.
Data traffic problems are encountered as cell sites become smaller in conventional wireless architectures. The base transceiver station serving each cell site is usually connected to a base station controller by a T
1
line. Each active call being handled by the base transceiver station is assigned to a dedicated time slot on the T
1
line. This type of connection has numerous drawbacks. The T
1
line has a relatively narrow bandwidth. The base station controller frequently collects from each base transceiver station out-of-performance data associated with the base transceiver station and the active calls it is handling. Performing this function requires a large amount of bandwidth, generally more than the T
1
can support simultaneously with on-going voice data transfers.
This problem is worsened by the increased use of high-bandwidth applications by the mobile units. For example, many of the mobile units may be portable computers executing multimedia applications, or video devices, such as video conference equipment. The T
1
bandwidth assigned to each mobile unit is simply too small to effectively perform these high-bandwidth applications. The result is that many video applications exhibit a flickering image and many audio applications exhibit a stuttering effect.
There is therefore a need in the art for improved wireless systems that provide reliable high-bandwidth communication links for mobile devices capable of performing multimedia and video applications. More particularly, there is a need for improved wireless infrastructures that provide a guaranteed amount of bandwidth with minimum latency to each active mobile unit.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide, for use in a wireless communication system, an infrastructure comprising 1) a plurality of client base transceiver stations operable to transmit voice and data signals to mobile units within the wireless communication system and to receive voice and data signals from the mobile units; and 2) a base station server coupled to the plurality of client base transceiver stations via a client-server backbone architecture, the base station server operable to transfer the voice and data signals between the plurality of base transceiver stations and an external wired communication system.
In one embodiment of the present invention, the base station server and the plurality of base transceivers stations communicate via an ISOchronous Ethernet client-server protocol.
In a preferred embodiment of the present invention, each of the plurality of client base transceiver stations operates under a CDMA access protocol.
In another embodiment of the present invention, each of the plurality of client base transceiver stations is assigned to selected transmit and receive frequencies. In certain embodiments of the present invention, the selected transmit and receive frequencies assigned to the plurality of client base transceiver stations are mutually exclusive.
In other embodiments of the present invention, the base station server assigns a sub-channel in the ISOchronous Ethernet to a selected wireless communication link between one of the plurality of base transceiver stations and a mobile unit.
In still another embodiment of the present invention, the base station server receives from at least one of the plurality of base transceiver stations RF performance data related to a selected wireless communication link between the at least one base transceiver station and a selected mobile unit.
In yet another embodiment of the present invention, the base station server comprises a base station transceiver operable to transmit voice and data signals to the mobile units and to receive voice and data signals from the mobile units.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
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Han John C.
Ho Duc
Hsu Alpus H.
Samsung Electronics Co,. Ltd.
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