Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1998-02-09
2001-05-15
Le, Thanh Cong (Department: 2684)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S435100, C455S426100, C455S428000
Reexamination Certificate
active
06233463
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to mobile communications systems and, in particular, to terrestrial cellular and mobile satellite communications systems.
BACKGROUND OF THE INVENTION
Mobile satellite communications systems are being employed worldwide. In general, previous systems have been regional in nature. However, global systems are being proposed and introduced. These global systems offer the potential for international roaming and, as a result, a need will exist for user terminals which can allow worldwide roaming. That is, a need will exist for a user terminal that can be used to make and receive calls without regard for geographic, economic, or political boundaries.
Single mode satellite user terminals (i.e., satellite only) can allow worldwide access. However, with the wide spread deployment of cellular, Personal Communications Systems (PCS) and other terrestrial mobile systems there will be a logical need to inter-work with such systems. For example, in such systems, and for dual mode terminals (e.g., analog/digital), it is often the case the digital mode is preferred, and is automatically selected where available.
Such inter-working is cost effective and may increase user quality of service in urban and suburban environments, while the satellite service can be used in rural areas and areas where terrestrial mobile service is not available or economical.
In order to accomplish such inter-working a dual mode user terminal may be required. That is, a user terminal capable of operating in either the satellite or the terrestrial cellular environment.
It is envisaged that mobile users will be roaming in both of these environments. The terrestrial environment is generally limited to those service areas which have land-based repeaters (towers, etc.) or other local area repeaters (e.g., balloons or aircraft). Necessarily, these mobile service areas are rather small, and are generally located in cities, towns and along heavily traveled roads. The satellite system, on the other hand, provides ubiquitous coverage and includes both the terrestrial mobile service areas and non-terrestrial service areas.
Terrestrial mobile systems do not have perfect coverage, especially at the fringe of cell areas, and furthermore many have “holes” or “gaps” within their service areas due to terrain blocking or other reasons. Users of terrestrial mobile systems can experience dropped calls and service when located within these fringe areas and holes. Satellite systems can fill these holes and fringe areas if the user terminals can inter-work sufficiently to assure proper technical connection and switch-over from one system to another.
At present, there are no currently existing or proposed terrestrial/satellite communications systems known to the inventors that adequately address these important needs.
It is noted that in an article entitled “An Integrated Satellite-Cellular Land Mobile System for Europe” (1989), E. Del Re describes a proposal for integrating a satellite communication system with the European GSM terrestrial cellular system. In the Del Re approach is it desirable to maintain common protocols (layers 2 and 3) between the satellite and GSM systems, with the majority of the differences being in the layer 1 (e.g., RF bands and synchronization procedures).
In U.S. Pat. No. 5,073,900, entitled “Integrated Cellular Communication System”, A. Mallinckrodt describes a cellular communications system having fully integrated surface and satellite nodes. That is, space node satellite cells can overlap ground cells. A system network control center is used to designate handling for a particular call to one of a satellite node or a regional node control center. Mallinckrodt mentions that in one embodiment the user can select whether to use the satellite link or the ground-based link.
Neither Del Re or Mallinckrodt is seen to provide a satisfactory solution to the problem of providing full inter-working between a satellite communication system and one or more existing terrestrial communication systems.
OBJECTS OF THE INVENTION
It is a first object of this invention to provide methods and apparatus for enabling an inter-working between one or more terrestrial mobile systems and a mobile satellite system.
It is a second object of this invention to provide methods and apparatus for providing automatic call management between one or more terrestrial mobile systems and a mobile satellite system.
It is a further object of this invention to provide a multiple mode user terminal having an ability to select or have selected for it a preferred initial condition, and to provide methods and apparatus for enabling automatic switching between these conditions.
SUMMARY OF THE INVENTION
The foregoing and other problems are overcome and the objects of the invention are realized by methods and apparatus in accordance with embodiments of this invention.
In one aspect this invention teaches a communications system having a satellite communications component comprising at least one satellite and at least one terrestrial gateway, and also a wireless terrestrial communications component comprising at least one repeater and at least one mobile switching center. The at least one gateway and the at least one mobile switching center are coupled together by a first mobile applications part network. The at least one gateway and the at least one mobile switching center are further coupled to a terrestrial communications network. The system further includes at least one dual mode or higher (e.g., tri-mode) user terminal comprising a first transceiver for bidirectionally communicating with the gateway through the satellite, a second transceiver for bidirectionally communicating with the mobile switching center through the repeater, and a controller, responsive to one of a user selected or a gateway selected protocol, for selectively enabling either the first or the second transceiver for conveying a user communication to the terrestrial communications network.
Different service providers may use different air interface standards and related signalling protocols (e.g., IS-41 and IS-95). Such air interface standards and signalling protocols may be collectively referred to simply as a “protocol”, which is assumed for the purposes of this invention to encompass the physical and logical requirements to successfully communicate with a given satellite or terrestrial communication system.
The user terminal is responsive to a number of initial conditions (C). These include (a) operation through satellite only; (b) logged into the satellite system but authorized to switch to the terrestrial system; (c) logged into both the satellite and terrestrial systems, and an automatic network search mode begins with the satellite system; (d) logged into the terrestrial system only; (e) logged into the terrestrial system but authorized to switch to the satellite system; and (f) logged into both the satellite and terrestrial systems, and the automatic network search mode begins with the terrestrial system.
REFERENCES:
patent: Re. 32905 (1989-04-01), Baran
patent: 4901307 (1990-02-01), Gilhousen et al.
patent: 5010317 (1991-04-01), Schwendeman et al.
patent: 5073900 (1991-12-01), Mallinckrodt
patent: 5081703 (1992-01-01), Lee
patent: 5109390 (1992-04-01), Gilhousen et al.
patent: 5119225 (1992-06-01), Grant et al.
patent: 5216427 (1993-06-01), Yan et al.
patent: 5233626 (1993-08-01), Ames
patent: 5239671 (1993-08-01), Linquist et al.
patent: 5265119 (1993-11-01), Gilhousen et al.
patent: 5303286 (1994-04-01), Wiedeman
patent: 5339330 (1994-08-01), Mallinckrodt
patent: 5410728 (1995-04-01), Bertiger et al.
patent: 5415368 (1995-05-01), Horstein et al.
patent: 5422647 (1995-06-01), Hirshfield et al.
patent: 5433726 (1995-07-01), Horstein et al.
patent: 5439190 (1995-08-01), Horstein et al.
patent: 5446756 (1995-08-01), Mallinckrodt
patent: 5448623 (1995-09-01), Wiedeman et al.
patent: 5511233 (1996-04-01), Otten
patent: 5535430 (1996-07-01), Aoki
patent: 5551624 (1996-09-01), Horstein et al.
patent: 5564076 (1996-10-01), Auvray
Sites Michael J.
Wiedeman Robert A.
Cong Le Thanh
Corsaro Nick
Globalstar L.P.
Ohlandt Greeley Ruggiero & Perle L.L.P.
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