Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1998-01-23
2002-12-17
Legree, Tracy (Department: 2681)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S561000, C455S513000, C455S552100, C455S524000, C455S436000
Reexamination Certificate
active
06496707
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to wireless communications and, more specifically, to a system and method for optimizing a wireless network by adaptive configuration of base stations and wireless terminals.
BACKGROUND OF THE INVENTION
Recent legislation in telecommunications promote competition among telephone service providers by allowing long distance carriers to enter into the local telephone market to compete with local service providers. The competition provides benefits such as competitive pricing and one-stop shopping for international and domestic long distance and local service. Long distance carriers seeking to enter the local telephone market face severe disadvantages, however, in competing with the entrenched local service providers. One disadvantage results from the local service provider's ownership of a local loop, the wired connection from a local service provider's central office to its customers' telephones at individual homes and businesses. Long distance carriers may either lease the local loop from the local service providers, or they may build their own networks, connecting customers' telephones to the central office. Since the local loops are currently leased at high prices, many long distance carriers seeking to enter the local telephone market have chosen instead to build their own networks.
It has proven uneconomical to build the new networks using wire. Therefore, many long distance carriers have chosen to bypass the local loops entirely with the use of wireless networks (giving rise to the term “wireless bypass networks”). Wireless bypass networks are essentially stationary versions of cellular communications networks, consisting of a network of multiple base stations with fixed antennas, connected to wireless terminals placed in customers' homes and businesses.
Wireless bypass networks thus provide an economically sound solution to the problem of connecting individual customers to the communications network. Wireless bypass networks, however, have some inherent problems.
One problem, commonly found in wireless networks, is poor signal quality. Although users may tolerate low signal quality and dropped connections with respect to their cellular phones, they expect and receive a much higher level of service from the local loops. Service providers wishing to enter the local market must therefore focus on improving signal quality to provide service comparable to that of the local loops.
Another problem, commonly found in cellular networks, is traffic overload. Since the cost of initially installing a large number of base stations is prohibitively high, service providers typically start operations with a small number of base stations, installing additional base stations as traffic increases. With a smaller number of base stations, traffic overload situations are more likely to occur. Cellular systems experience traffic overloads during peak usage hours. When this occurs, many cellular users are unable to place calls on an initial attempt and must redial, sometimes repeatedly, until the base station is able to process the call. Cellular users are typically willing to accept this inconvenience in exchange for mobility. Home and business users, however, are much less tolerant of traffic overloads. A successful wireless bypass network, therefore, must be able to effectively resolve the traffic overload problem.
Accordingly, there is a need in the art for systems and methods that provide optimal and automatic load-sharing among the base stations in a wireless network. More specifically, there is a need in the art for improved systems and methods that allow a wireless network to adapt itself optimally and automatically to a given geographical distribution of base stations and wireless terminals.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, the present invention provides, for use in a wireless network having geographically-distributed base stations that serve wireless terminals, a system for, and method of, improving an operation of the wireless network. In one embodiment, the system includes: (1) a signal quality determination circuit that determines a relative quality of signals communicated between one of the wireless terminals and a set of base stations within range of the one of the wireless terminals and (2) a base station selection circuit, coupled to the signal quality determination circuit, that selects a base station in the set to serve the one of the wireless terminals based on the relative quality of signals.
The present invention therefore introduces a way to improve the operation of a wireless network by examining at least some of the signals in the network and making base station/wireless terminal pairing decisions based thereon.
In an alternative embodiment of the present invention, the system is contained within the one of the wireless terminals. In this embodiment, the present invention provides a way for a given wireless terminal to select the “best” base station to use.
In an alternative embodiment, the system is associated with each of the base stations. In this embodiment, the base station selection circuit optimizes an assignment of the wireless terminals to the base stations based on the relative quality of signals. This results in an improvement in wireless network operation that is more from the perspective of the network. In a more specific embodiment, the base station selection circuit further optimizes the assignment of the wireless terminals to the base stations based on a loading of the base stations thereby to optimize an overall traffic assignment of the wireless network. In some applications, optimizing solely based on signal quality may result in uneven loading of base stations, harming overall wireless network operations. It may prove valuable, therefore, to consider base station loading in addition to signal quality when making traffic assignment decisions.
In an alternative embodiment of the present invention, the one of the wireless terminals is associated with a fixed location. “Fixed location” is defined as a sedentary venue, such as a house, an apartment, an office suite, or the like (those places served by wireless bypass networks), as opposed to a moving location, such as a vehicle. Of course, those skilled in the art will readily see that the present invention is advantageous in conventional wireless networks wherein wireless terminals readily move about from one base station to another.
In an alternative embodiment of the present invention, the relative quality of the signals is determined with reference to a signal characteristic selected from the group consisting of: (1) signal strength, (2) signal distortion and (3) signal continuity. Those skilled in the art will readily perceive that other measures of signal quality may prove advantageous in certain applications.
In an alternative embodiment of the present invention, the signal quality determination circuit and the base station selection circuit operate continually. This means that traffic assignments in a given network may be made completely dynamic, dependent upon time of day, weather, traffic, addition or removal of base stations or any other network-affecting occurrence.
In an alternative embodiment of the present invention, one of the base stations has a multi-beam antenna associated therewith. In another embodiment of the present invention, one of the wireless terminals has a multi-beam antenna associated therewith. Of course, an electrically or mechanically steerable antenna may also be associated with the base station or the wireless terminal. The directional focusing ability of the multi-beam and steerable antennas allow the use of lower power levels, resulting in a decrease in electromagnetic interference with other sensitive electronic devices.
The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the inv
Chu Ta-Shing
Gans Michael J.
Yeh Yu Shuan
Hitt Gaines & Boisbrun
Legree Tracy
Lucent Technologies - Inc.
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