Motorola Corporation

Sergio Aguirre

Randy Lee Turcotte

Stephen Chih-Hung Ma

Rodrigo Ibanez-Meier

Kadathur S Natarajan

Christopher R Keate

Vijay K Kapoor

Gregory B Vatt

Richard Lawrence Astrom

Brian L Stockdell

A method and apparatus for communicating between wireless communication devices (120, 131, 140) uses a high-altitude communication platform (110) to provide an interface between the devices. The platform (110) enables multiple signals from multiple sources to be combined into one signal which is sent to a ground device (120). The ground device (120) can send a combined signal to the platform (110) which the platform (110) can then separate and send to multiple destinations. The platform (110) can be used as a bridge between satellites (1310, 1312) which are incapable of direct communication, thus enabling a fully connected network to exist without full coverage from satellites.

Elevated communication hub and method of operation therefor

A communication network (20) includes a multiplicity of switching nodes (18), many of which are located in orbiting satellites (16). Communication links (30) interconnect the switching nodes (18). A control center (32) performs a request for connection process (40) which routes a new call request over a current internodal topology of links (35) if possible. If the new call request cannot be routed over the current internodal topology of links (35), the process (40) determines how to augment the network with the creation of new links (45) so that the new call can be routed. As calls terminate, unused links are taken out of service.

Communication network and method for managing internodal link topology

A method and apparatus for communicating with a high-altitude communication platform (110) which combines multiple signals from multiple sources into one signal which is sent to a ground device (120). The ground device (120) can send a combined signal to the platform (110) which the platform (110) can then separate and send to multiple destinations. The ground device (120) also can provide spectral reuse by orienting directional antennas (360-362) toward the communication platform (110) and one or more spatially diverse other wireless devices.

Ground device for communicating with an elevated communication hub and

A method and apparatus for responding to a blockage environment (50) in a communication system includes creating (158, 163) a terminal blockage profile and/or a satellite blockage profile with respect to terminal antenna (19) and responding (200) to the terminal blockage profile and/or the satellite blockage profile to prevent fading and/or blocking of communication pathways (15, 18) between one or more satellites (12) and the terminal (16).

Method and apparatus to respond to a blockage environment in a

An intelligent digital beam former (10) in conjunction with a satellite based array antenna (20) provides a plurality of dynamically controllable antenna beams (52) for communication with subscriber units on earth's surface. The location of a subscriber unit (90) requesting communication services is determined and an individual antenna beams is formed and assigned to the subscriber unit. The antenna beam tracks the subscriber units as the satellite and/or the subscriber unit moves. The digital beam forming coefficients are dynamically adjusted and controlled to help maximize the signal quality of communications with the subscriber units.

Method and intelligent digital beam forming system with improved signal

A satellite communication network (10) coordinates multiple steerable satellite beams (28) with user requests for connections requiring varying bandwidth in real-time. A control station (22) gathers user requests for connections (64) and transmits those requests (70) to a satellite (20) over an uplink (70). Requests for bandwidth (72) are processed in the satellite (20) where time slot assignments (74) and steerable beam schedules (84) are determined in response to user requests (74). Steerable beam schedule (84) and time slot assignments (74) are transmitted to subscriber units (24) and control station (22) over a broadcast downlink (86). Subscriber units (24) complete a data transfer interval of a call (62) while a steerable beam schedule (84) is executed in real-time.

Network and method for controlling steerable beams

An intelligent digital beam former (10) in conjunction with a satellite based array antenna (20) provides a plurality of dynamically controllable antenna beams (52) for communication with subscriber units (90) on earth's surface. Interference is mitigated placing a null in the transmit and receive antenna patterns at the location of the interfering signal by adjusting digital beam forming coefficients. As the interfering signal moves relative to the satellite, the interfering signal is tracked to maintain interference mitigation. The digital beam forming coefficients are also dynamically adjusted to help maximize signal quality of communications with subscriber units.

Method and intelligent digital beam forming system for interference

An intelligent digital beam former (10) in conjunction with a satellite based array antenna (20) provides a plurality of dynamically controllable antenna beams (52) for communication with subscriber units (90) in response to demand for communication services. Geographic portions within the satellite's footprint that have a higher-demand for communication services are dynamically provided additional antenna beams while geographic portions having a lower demand for communication services are provided less antenna beams. When used on a non-geostationary satellite, the digital beam forming coefficients are dynamically adjusted to steer the antenna beams to maintain their ground location. The antenna beams are also shaped to help optimized geographic coverage.

Method and intelligent digital beam forming system responsive to traffic

A synchronizer operates to achieve initial synchronization with a TDMA acquisition signal exhibiting a potentially large Doppler. The synchronizer collects samples of a baseband signal during a timing window. A fast Fourier transform (FFT) is performed on the samples to generate a set of spectral data. The window is moved to an identical point in a subsequent frame and the FFT repeated until a high-confidence spectral data set is obtained. If the spectral data set indicates energy concentrated around a discrete frequency, then that discrete frequency represents an estimate of the acquisition signal's frequency. The timing window's timing parameters represent a time slot estimate of the acquisition signal. If the spectral data set indicates energy spread more or less uniformly over the spectrum, then no estimates are indicated and a new window is positioned at a different point in subsequent frames.

Synchronizer for TDMA acquisition signal having an unknown frequency

Distortion introduced in phase modulated RF signals by amplifiers and other signal processors is substantially reduced by modifying complex modulating signals I,Q in a way that compensates for the amplifier phase error .phi..sub.e as a function of amplifier power P. In a preferred embodiment, I, Q are combined to calculate the amplifier power level and scaled by a parameter, e.g., K1=-d.phi..sub.e /dP, to provide factor B so that compensated signals I'=AQ+BI and Q'=AI-BQ, where A is a constant, can be determined. When an RF carrier modulated by I', Q' is passed through the distorting amplifier the amplifier induced distortion is cancelled. Substantial reduction in bit error probability is obtained. The method can also be used for post-distortion correction.

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Phoenix, AZ, United States of America

Sergio Aguirre