The Boeing Company

Christopher John McLain

Michael De La Chapelle

David S Parkman

Melvin Barmat

Gary V Stephenson

Paulus J Martens

Janet L King

John R Palmer

Joseph W Niesen

Implementations are described that use a control center to maintain a list of registered mobile platforms that are pre-authorized to make use of the satellite-based transponder to transmit and receive data content to and from the base transceiver. The control center may cause the base transceiver to transmit at least one polling message, the polling message carries information addressed to a specific aggregate group of the registered mobile platforms and includes a return channel which may be used by a mobile platform to communicate with the base transceiver. In one implementation, the control center protects the system from exceeding power spectral density (PSD) statistical limits by using the mobile platform in the group that has a greatest power spectral density signal as the PSD that the aggregate group will generate.

Aggregate batch polling method for return link communications between a platform and a base station

A system and method for monitoring and adjusting the data transmission rate of a forward link RF signal from a base station to a mobile platform to maintain a desired, minimum link margin with each of the mobile platforms. The system involves using a signal quality monitoring subsystem carried by each mobile platform during the normal course of its operation to transmit signal quality information via a return link to the base station. The base station uses the signal quality information to monitor and adjust the signal quality of subsequent forward link signals transmitted to the mobile platforms in a manner that optimizes the data transmission rate of the forward link signals. The present invention better accounts for time varying factors that influence the signal quality of received forward link signals by the mobile platforms and obviates the need for mobile test platforms or other expensive and relatively complex methods for predicting needed data transmission rates for the forward link signals.

Method and apparatus for optimizing forward link data rate for radio frequency transmissions to mobile platforms

A satellite communications method for communicating information from a base station, via a satellite, to one or more user terminals via a single channel of a forward link.

System and method for adaptive information rate communication

In a system for providing data content to and from a plurality of mobile platforms where each of the mobile platforms transmits a return link having an EIRP to a predetermined location via a satellite-mounted transponder, a method for controlling an EIRP of the aggregate return link emissions of the mobile platforms. The method includes the steps of determining a probability distribution of the EIRP of the return link for each of the mobile platforms; and determining a probability distribution of the EIRP for the aggregate return link emissions using the probability distributions of the EIRP of the return link for each of the mobile platforms; determining an aggregate off-axis EIRP density envelope for a predetermined probability level and the probability distribution of the EIRP for the aggregate return link emissions.

EIRP statistical calculation method

A method and apparatus for identifying which one of a plurality of mobile terminals in communication with a ground-based base station, via a transponded satellite, is causing interference with a non-target satellite orbiting in a vicinity of the transponded satellite. The method involves using the base station to sequentially check each of the mobile terminals to identify which one is causing the interference. The check is made by the base station commanding each mobile terminal to modulate the power level of its transmitted signals and then checking with an operator of the interfered with non-target satellite to see if the interference condition has changed. Once the mobile terminal causing the interference condition is identified, the base station can command the mobile terminal to reduce its transmit power accordingly.

Method and apparatus using variations in power modulation to determine an interfering mobile terminal

A method for rapidly identifying which one of a plurality of mobile wireless terminals on-board a corresponding plurality of mobile platforms, such as aircraft, accessing a target transponded satellite, is causing interference with one or more non-target satellites orbiting in proximity to the target satellite. The method involves dividing the plurality of mobile wireless terminals into two groups and commanding one-group of terminals to stop transmitting. A check is then made to determine which group of terminals is causing the interference. That particular group is then subdivided successively by a factor of 2 and alternately checked to see if it is still causing the interference until a single mobile terminal is identified as the source of the interference. This binary technique of successively subdividing all of the terminals into smaller and smaller subpluralities allows the terminal which is causing the interference to be quickly identified from a large plurality of terminals accessing the target transponded satellite.

Method and apparatus using a binary search pattern for identifying an interfering mobile terminal

A system and method for quickly detecting and remedying an interference incident caused by one of a plurality of mobile terminals in communication with a transponded satellite. The method makes use of a time line constructed from communications of each of the mobile terminals. The time line forms a real time, sequential record of events wherein various mobile terminals have made contact with the transponded satellite. The method extrapolates from the time line which one of the mobile terminals has caused an interfering event by determining which mobile terminal accessed the communication system just prior to the interference event arising.

Method and apparatus using event correlation for identifying an interfering mobile terminal

A method for rapidly identifying which one of a plurality of mobile radio frequency (RF) terminals on-board a corresponding plurality of mobile platforms, such as aircraft, accessing a target transponded satellite, is causing interference with one or more non-target satellites orbiting in proximity to the target satellite. The method involves dividing the plurality of mobile RF terminals into two groups and commanding one group of terminals to stop transmitting. A check is then made to determine which group of terminals is causing the interference. That particular group is then subdivided successively by a factor of 2 and alternately checked to see if it is still causing the interference until a single mobile terminal is identified as the source of the interference. This binary technique of successively subdividing all of the terminals into smaller and smaller subpluralities allows the terminal which is causing the interference to be quickly identified from a large plurality of terminals accessing the target transponded satellite.

A method for rapidly monitoring and detecting a mobile terminal causing RF interference with one or more satellites orbiting in the vicinity of a target satellite, from a plurality of mobile terminals accessing the target satellite. Each mobile terminal performs a transmit lobing signal sequence and a ground-based component in the form of a Network Operation Center (NOC) analyzes the signals transmitted by each mobile platform. The NOC determines a ratio of energy-per-bit to noise spectral density (Eb/No) value for the signals transmitted by each mobile platform and compares these values to a predetermined Eb/No value. If the Eb/No values for a given mobile platform deviate by more than a predetermined magnitude from the predetermined Eb/No value, then the NOC identifies that given mobile platform as causing the unintended RF interference with the adjacent satellite(s).

Method and apparatus using transmit beam lobing for identifying an interfering mobile terminal

An apparatus and method for correcting antenna beam misalignment between a transmit antenna and a receive antenna on a mobile platform such as an aircraft. The beam alignment method makes use of sequential lobing to determine the pointing angles in azimuth and elevation of a receive beam received by the receive antenna. For the transmit antenna, sequential lobing is used for the transmit antenna beam transmitted to a transponded satellite and then to a ground station. The ground station performs received signal strength indicator (RSSI) measurements and transmits these measurements back to the aircraft via the target satellite. From these measurements, the beam misalignment between the receive and transmit antenna beams, both in azimuth and elevation, can be determined and a correction applied to the transmit antenna. The beam alignment procedure of the present invention can be implemented without interfering with normal use of the transmit and receive antennas and further ensures that interference with satellites adjacent to the target satellite will not occur during return link transmissions from the aircraft to the ground station.

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Seattle, WA, United States of America

Christopher John McLain