Globalstar, Inc.

Michael J Sites

Robert A Wiedeman

Paul A Monte

Vijaya Korwar Gallagher

John A Serri

Disclosed are methods and apparatus to control the actions of a user terminal (UT) located at a remote location, possibly far from a gateway (GW), which has an interface to the Public Switched Telephone Network (PSTN) and/or to the Internet. The methods and apparatus provide for operation of a mobile satellite communication system having at least one gateway (GW), at least one user terminal (UT), and a constellation of satellites. The methods and apparatus allow access to the communication satellites by specifying an exclusion zone having a confidence limit (CL) associated therewith. The methods and apparatus selectively provide service to a UT depending on a determined location of the UT relative to the exclusion zone and on an estimated error (E) of the determined UT location, wherein location of the UT is determined by the UT, and transmitted to the GW, or location of the UT is determined by the GW.

Method and apparatus providing suppression of system access by use of confidence polygons, volumes and surfaces in a mobile satellite system

A method is disclosed for operating a satellite communications system for coupling a user terminal to a data communications network. The method has steps of (a) establishing a connectionless packet data transmission link between the user terminal and a gateway that is coupled to the user terminal through at least one satellite via an inbound link and an outbound link, the gateway being further coupled to the data communications network and being associated with a gateway service provider; (b) deriving billing-related information by counting a number of units of data that comprise data packets that are transmitted over at least one of the inbound link and the outbound link; (c) aggregating the billing-related information with billing-related information for other user terminals; (d) transferring the aggregated billing-related information to a satellite communication system operator site; and (e) at the satellite communication system operator site, determining an amount to bill the gateway service provider based at least in part on the aggregated billing-related information. The step of establishing the connectionless packet data transmission link may include a step of varying a bandwidth of the link to accommodate different data rate requirements.

Method and apparatus for accounting for user terminal session-based connection to a satellite communication system

In a communication satellite constellation which uses CDMA and multiple spot beams for point-to-point communication, a system is provided for broadcasting regionally related information within a spot beam by establishing a Frequency/Walsh Code Tiling over the Earth's surface, and enabling a user terminal at a given position to tune to an appropriate frequency and Walsh Code to receive the information broadcast from a satellite over a forward beam downlink. The information, e.g. regional messages such as local weather or traffic, is transmitted to the satellite from a ground station or gateway that receives the information from a Broadcast Processing Center. In a preferred embodiment a dedicated Frequency Division Multiplex (FDM) channel within each spot beam transmits the regional broadcast messages at the Tiles in accordance with the Walsh Code designations of the Tiles.

Methods and apparatus for broadcasting regional information over a satellite communication system

A method includes steps of establishing a wireless connection with a user terminal through a forward link and a return link; determining, during the connection, if an averaged transmitted power density associated with an antenna of the user terminal will equal or exceed, relative to a user of the terminal, at least one of a predetermined threshold level, within a specified unit of time, and an absolute threshold level; and taking action to reduce or eliminate the transmitted power at a time prior to or when the averaged transmitted power density level equals or exceeds the threshold level. The step of determining includes a step of considering the operation of the user terminal in a satellite communications system as well as in a terrestrial communications system. The step of taking action includes a step of reducing the transmitted power of the user terminal by at least one of: assigning the user terminal to another frequency channel, assigning the user terminal to another time slot, changing a number of satellites through which the user terminal is communicating, or changing a data rate at which the user terminal is transmitting. The step of establishing a wireless connection includes a step of assigning at least one communications system parameter to the user terminal based at least in part on a historical record of how quickly the user terminal approaches the threshold.

Method and apparatus for considering user terminal transmitted power during operation in a plurality of different communication systems

A satellite communication system (,) includes at least one satellite communication signal repeater (,); at least one ground station (,) for transmitting a feeder link comprised of a plurality of communication signals to the at least one satellite communication signal repeater; and a plurality of user terminals (,) each receiving one of the communication signals over a user link from the at least one satellite communication signal repeater. A method includes steps of measuring a quality of at least one reference signal received by the user terminal, via the satellite; transmitting the measured quality of the reference signal received by the user terminal to the ground station; comparing the measured quality with a predetermined reference; and adjusting a transmit power of the ground station in response to a difference between the predetermined reference and measured quality. The transmit power of the ground station is adjusted so that a flux density of a downlink beam is substantially constant at the user terminal independent of the location of the user terminal in the beam.

Closed loop power control for low earth orbit satellite communications system

A communications system includes a satellite communications component having at least one satellite and at least one terrestrial gateway, and also a wireless terrestrial communications component having 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 (MAP) network, such as an IS-41 or GSM MAP network. The at least one gateway and the at least one mobile switching center are further coupled to a terrestrial communications network (PSTN). The system further includes at least one dual mode or higher user terminal having 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.

Automatic satellite terrestrial mobile terminal roaming system and method

A method and system wherein a system gateway (18) determines, from closed loop power control information, a power density at an antenna (13a) of a user terminal 13. The gateway also maintains a record of a duration of time that the power density exceeds a specified threshold. The gateway determines if an averaged transmitted power density associated with the antenna of the user terminal will equal or exceed at least one of a predetermined threshold level, within a specified period of time, or an absolute threshold level. If the gateway determines that a threshold will probably be exceeded if the call connection is maintained, the gateway terminates the connection prior to a time that the user terminal averaged transmitted power density level equals or exceeds the predetermined or absolute threshold level. A tone or a visual indicator may be employed to warn the user that a current connection or call will be terminated. Provisions are made for allowing predetermined types of calls (e.g., emergency calls) to be made during a cutoff period wherein the user terminal is prohibited from placing further calls. It within the scope of the invention to perform the power density monitoring function also within the user terminal. In this case information may be transferred to the GW over a return link, and majority voting or some other technique can be employed by the GW before terminating the connection. In this case the power density determination made at the GW has priority over that made in the user terminal to prevent a user terminal from intentionally or inadvertently defeating the power density monitoring function.

Satellite communications system having gateway-based user RF exposure

A satellite communication system (10) includes at least one satellite communication signal repeater (12); at least one ground station (18) for transmitting a feeder link comprised of a plurality of communication signals to the at least one satellite communication signal repeater; and a plurality of user terminals (13) each receiving one of the communication signals over a user link from the at least one satellite communication signal repeater. The satellite communication system further includes a closed loop power control system (80) having a plurality of inner loops (84), individual ones of which operate to compensate one of the user links for communication signal impairments occurring at least between the user terminal and the at least one satellite communication repeater, and an outer loop (82) which operates to compensate all of the user links for feeder link impairments occurring between the at least one ground station and the at least one satellite communication signal repeater.

Closed loop power control for low earth orbit satellite communications

A communications system includes a satellite communications component having at least one satellite and at least one terrestrial gateway, and also a wireless terrestrial communications component having 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 (MAP) network, such as an IS-41 or GSM MAP network. The at least one gateway and the at least one mobile switching center are further coupled to a terrestrial communications network (PSTN). The system further includes at least one dual mode or higher user terminal having 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.

Automatic satellite/terrestrial mobile terminal roaming system and method

A method and system for accurately accounting for an amount of satellite communications system resources that are allotted to and utilized by a user terminal on a per call or connection basis. The method accumulates data at periodic intervals during a connection, the data indicating what portion of the overall system resources are utilized on both a forward link (gateway to satellite(s) to user terminal) and on a reverse link (user terminal to satellite(s) to gateway). The usage data can include power levels, data rates, user terminal location, and user terminal type. A Gateway (18) that is assigned to handling the call for the user terminal (13) accumulates the data and subsequently transfers the data over a terrestrial data network (39) to a Ground Operations Control Center (38). The center uses the data to determine an amount to be billed to a service provider associated with a service area that includes the gateway. The center may also uses this data to derive statistical information describing the communications traffic handled by the gateway, and to derive predicted resource allocation and resource scheduling information for the gateway.

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Fremont, CA, United States of America

Michael J Sites