Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
2000-12-22
2004-10-12
Chin, Vivian (Department: 2682)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S445000, C455S553100, C455S426100, C455S067110, C455S067140, C370S328000, C370S332000, C370S333000, C370S338000, C370S252000
Reexamination Certificate
active
06804532
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to the field of communications, and more particularly to a system and method for routing communications based on wireless communication link quality.
BACKGROUND OF THE INVENTION
In a typical cellular telephone system, mobile stations (for example, cellular telephones) communicate with base stations using wireless communication links. The base stations are coupled to a base station controller, which is coupled to a mobile switching center. Communications from the mobile station are sent to the base station controller. The base station controller may forward the communications to another mobile station using the same or another base station in the cellular network. Alternatively, the base station controller may forward the communications to the mobile switching center for communication to another network, such as another cellular network, the public switched telephone network, the Internet, or any other appropriate networks.
As a mobile station moves away from a base station, the ability of the mobile station to communication with the base station may be impaired. However, as this impairment of communications occurs, other base stations in the same cellular network may come within range of the mobile station. Therefore, the responsibility for supporting communications with the mobile station may be transferred from one base station to another. This transfer of responsibility (or “handoff”) is typically controlled by the mobile switching center and/or the base station controller, not by the mobile station. Handoffs within a single cellular network are typical and may often be performed with minimal effect on communications with the mobile station. However, a handoff between base stations in different cellular networks, when available, is more complicated and often has a detrimental effect on communications with the mobile station.
Furthermore, mobile stations are increasingly being outfitted with additional communication interfaces to allow the mobile station to communicate with other types of networks and stand-alone devices. As with handoffs between different types of cellular networks, handoffs of communications between these different technologies is also difficult or unavailable.
SUMMARY OF THE INVENTION
According to the present invention, disadvantages and problems associated with previous routing systems and methods have been substantially reduced or eliminated.
According to one embodiment of the present invention, a method for re-routing communications based on link quality includes establishing a first wireless communication link with a mobile station. The first wireless communication link is included in a first communication path used for communications between the mobile station and a destination device. The method also includes monitoring, from the mobile station, the link quality of the first wireless link and determining, at the mobile station, that the link quality of the first communication link has decreased below a low link quality threshold. The method further includes routing, using a router at the mobile station, communications between the mobile station and the destination device to a second communication path that includes a second wireless communication link to the mobile station. The second communication path is selected by the router based on one or more metrics.
The system and method of the present invention provide a number of important technical advantages. Unlike devices having a fixed location, the availability and quality of communication links, typically wireless communication links, with a mobile station may vary. Embodiments of the present invention account for the effect of this changing environment when routing communications to and from the mobile station. Certain embodiments of the present invention also provide transparent “re-routing” of communications by the mobile station from one communication link to another as the link quality of a communication link being used decreases and as other communication links become available. Furthermore, such transparent re-routing or “handoff” is provided between diverse communication networks and technologies. Other important technical advantages are readily apparent to those skilled in the art from the following figures, descriptions and claims.
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Moon Billy G.
Smith Malcolm M.
Chin Vivian
Cisco Technology Inc.
Dao Minh D.
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