Multiplex communications – Channel assignment techniques – Messages addressed to multiple destinations
Reexamination Certificate
1999-12-17
2003-11-11
Olms, Douglas (Department: 2661)
Multiplex communications
Channel assignment techniques
Messages addressed to multiple destinations
C370S390000, C455S518000
Reexamination Certificate
active
06647020
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to communication systems, and particularly communication systems incorporating multicast internet protocol (IP) addressing.
BACKGROUND OF THE INVENTION
Communication systems typically include a plurality of communication units, such as mobile or portable radio units and dispatch consoles that are located at multiple sites. Typically, the various sites include base site repeaters (“repeaters”) for transceiving information such as control, voice, data and network management traffic between the communication units and each other. The communication units are often logically divided into various subgroups, known as talkgroups, which can be made up of communication units at different sites desiring to participate in a group or dispatch call. A dispatch call is one in which members of a particular talkgroup can communicate with each other via communication links established between multiple endpoints, such as voice repeaters and dispatch console positions.
There are a variety of architectures that will support group or dispatch call connections between multiple endpoints. Perhaps the most commonly known is a “circuit-switched” architecture in which at least one base station or repeater at each site is linked, through dedicated or on-demand circuits, to a central radio system switching point (“central switch”) in what is often called a “star” configuration. Some very large systems use a hierarchy of such “stars” where intermediate processors group the links from multiple cell sites and do some lower level processing on them before passing them up to the central switch. In either case, the circuits providing connectivity to the central switch require a dedicated wire for each endpoint whether or not the endpoint is participating in a particular call.
Next generation radio systems propose to employ multicast addressing protocols, such as multicast Internet Protocol (IP) for providing group or dispatch call services. One example is U.S. patent application Ser. No. 09/283,121, titled “Wireless Communication System Incorporating Multicast Addressing and Method For Use,” assigned to Motorola, Inc. and incorporated herein by reference in its entirety. Generally, IP multicasting protocols provide one-to-many or many-to-many communications capability in a connectionless packet network. The network defines a spanning tree of router interfaces and necessary routes between those interfaces to provide multicast distribution of data with a minimum amount of data replication. Moreover, with multicast routing protocols, there is no need for dedicated bandwidth to each endpoint, thus dispatch service can be provided relatively more efficiently and less costly than in traditional circuit-switched networks.
Because networks using IP multicasting protocols offer several advantages relative to traditional circuit-switched networks, there is a continuing need to develop and refine communication architectures using IP multicasting, particularly for implementing dispatch calls with multiple endpoints. As such, there is a need to define systems and methods for endpoints, including base site voice repeaters and dispatch consoles, to use various components of an IP multicast network for setting up and ending talkgroup calls. The present invention is directed to satisfying these needs.
REFERENCES:
patent: 5761193 (1998-06-01), Derango et al.
patent: 5835723 (1998-11-01), Andrews et al.
patent: 5910946 (1999-06-01), Csapo
patent: 6134587 (2000-10-01), Okanoue
patent: 6477149 (2002-11-01), Okanoue
Biggs Robert
DeRango Mario
Maher John W.
McDonald Daniel J.
Hughes Terri S.
Motorola Inc.
Olms Douglas
Phunkulh Bob A.
Santema Steven R.
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