Abstract: 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.

Abstract: A method is disclosed for operating a satellite communications system for coupling a user terminal to a data communications network.

Abstract: 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.

Abstract: A method for determining whether a gateway will service a user terminal in a satellite communication system comprises the steps of (1) determining whether a position of the user terminal is ambiguous, and (2) if the position is ambiguous, then (a) determining whether a previous registration of a service provider for the user terminal matches a current service provider accessible via the gateway, and (b) if the previous registration matches the current service provider, then accepting the user terminal for service by the gateway. Alternate methods involve determining that the user terminal is at either of two ambiguous positions, and (1) determining whether both of the two ambiguous positions are within a service area of the gateway, (2) determining whether at least one of the two ambiguous positions is within a restricted area for which the gateway does not provide service, or (3) determining a parameter of a beam transmitted from the user terminal to a satellite of the satellite communication system.

Abstract: 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. A computer generated and stored database of an area (referred to as a Confidence Polygon), a volume (referred to as a Confidence Volume), and/or a plane (referred to as a Confidence Surface) is used to establish a geometric shape located on the earth, above the earth or in space, or combinations thereof. In addition, there is assigned to these areas, volumes and/or planes a static or a variable value referred to as a Confidence Limit (CL) that can be compared to a value of an error (E) in a position location of the UT. The error signal can either be generated by the UT or by the GW.

Abstract: 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.

Abstract: 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. 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.