Motorola Corporation

James William Startup

Thomas Peter Emmons, Jr

Robert Anthony Peters

Jonathan Henry Gross

Shawn Wesley Hogberg

Duke Edward Hanson

Peter Monsen

Norbert Kleiner

John Richard Erlick

Jim E Helm

Joel Lloyd Gross

William Joe Haber

Lansing M Carson

Craig L Fullerton

Robert J Burdge

Cynthia C Matthews

John G Lambrou

Michael Dane Ince

Allen H &lsquo;Skip&rsquo; Nelson

Ruby Figor Hutchins

Stephen Chi Humg Ma

David L Krueger

Susan L Harris

The present invention utilizes a dual polarization reception system () that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (), and this circuitry determines the most likely state of a received symbol's transmitted value.

Mobile satellite communication system utilizing polarization diversity combining

A communication system provides multiple wireless services, each potentially having a different information bit rate. A transmitter (, FIG.) encodes (, FIG.) relatively low rate data (, FIG.) using code division multiple access (CDMA). The resulting spread data stream(s) (, FIG.) are multiplexed and modulated (, FIG.) along with relatively high information rate, non-encoded data streams (, FIG.) using a time division multiple access/frequency division multiple access (TDMA/FDMA) protocol. In other embodiments, the methods and apparatus of the present invention can be used in a CDMA only system, or in a system using a time division multiplexing/FDMA and time division multiplexing/CDMA. In one embodiment, the spread data streams are transmitted in timeslots (, FIG.) and frequencies (, FIG.) that are interspersed between timeslots and frequencies used for the high rate data. A receiver (, FIG.) performs complementary demodulation (, FIG.), demultiplexing (, FIG.), and decoding (, FIG.).

Methods and apparatus for providing multiple wireless communication services having different bit rates

A method of increasing satellite communication quality by using a MEO satellite constellation ( ) and a LEO satellite constellation ( ) in combination with a decision algorithm which selects the appropriate constellation to route a communication signal through. The decision algorithm can be embodied in three ways: gateway based ( ), individual subscriber unit based ( ) and satellite based ( ). The MEO constellation ( ) and LEO ( ) constellation may be cross-linked, allowing for switching of service between satellites, as needed, during a communication session.

System for providing optimal satellite communication via a MEO/LEO satellite constellation

An airborne repeater antenna array ( ) in which beams transmitted from multiple antenna elements ( ) of the array to form terrestrial communications. cells are shaped according to predetermined system parameters. At least one of airplane telemetry data ( ) indicating an airplane flight pattern location, adjacent cellular system beam footprint data, and call distribution load within a terrestrial cell are received, and a complex gain is dynamically computed for each of the multiple antenna elements based on such data to thereby output a plurality of beams that form desired geographic communications coverage cells ( ).

Smart antenna for airborne cellular system

A beam control subsystem ( , FIG. ) provides acquisition, synchronization, and traffic beams ( , FIG. ) to communication devices ( ) within a footprint ( ) of a system node ( ), where each beam comprises a set of beamlets ( ). The subsystem ( , FIG. ) first acquires ( , FIG. ) and synchronizes ( , FIG. and FIG. ) with each communication device. Acquisition involves selecting ( , FIG. ) and combining ( ) sets of beamlets ( , FIG. ), and determining whether any devices within the sets are attempting to acquire the system. If so, synchronization is performed by varying ( , FIG. ) beamlet weighting coefficients to find, based on modem feedback, a combination of coefficients that yields a maximum signal-to-interference&plus;noise ratio for multiple users within a beam. The communication device is then handed off ( ) to a traffic beam. The subsystem ( ) continues, based on modem feedback, to adapt ( , FIG. ) beamlet weighting coefficients in order to track the traffic beam in a manner that provides the maximum SINR.

Method and apparatus for controlling communication beams within a cellular communication system

The present invention utilizes a dual polarization reception system ( ) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry ( ), and this circuitry determines the most likely state of a received symbol's transmitted value.

A method and apparatus for acquiring satellite signals and subscriber unit signals utilizes broadcast beams ( ) and acquisition beams ( ) projected from a satellite ( ). The broadcast beams ( ) and acquisition beams ( ) form broadcast acquisition beam pairs that are swept within the footprint ( ) of the satellite ( ) on the surface of the earth. Broadcast bursts are transmitted by the satellite ( ) in the broadcast beams ( ), and acquisition bursts broadcast by subscriber units ( ) are received by the satellite ( ) in acquisition beams ( ).

Signal acquistion method and apparatus

A method and apparatus for soft decision propagation trades off system bandwidth in return for link margin. When signal quality on an uplink is low, a satellite ( ) sends soft decision data, rather than hard decision data, to a gateway ( ). When path diversity exists on the uplinks, and multiple satellites ( ) receive the uplink, multiple versions of soft decision data are sent to the gateway ( ). The gateway combines the soft decision data resulting from multiple uplink paths, thereby increasing the effective uplink signal to noise ratio.

Method and system for soft decision propagation

In a code division multiplexed system, a subscriber unit (,, FIG.,), which includes a pseudonoise code generator (,), is synchronized with the pseudonoise code generator (,) of a communications node (,). Synchronization between the pseudonoise code generators (,) is achieved through measuring the time delay of a signal transmitted from the communications node (,) to the subscriber unit (,) and advancing the code generator of the subscriber unit in accordance with the time delay. This permits transmissions from the subscriber unit (,) to be received synchronously at the satellite. The synchronization is maintained through the periodic transmission from the communications node (,) to the subscriber unit (,) of a message which commands the subscriber unit (,) to adjust the timing of its pseudonoise code generator. The resulting synchronous code division multiplexed system offers increased capacity over conventional systems.

Method and system for synchronous code division multiplexed communications

A phase domain multiplexed communication system generates N carrier frequencies each with a unique phase according to a selected orthogonal vector containing N elements. A subscriber information signal is first divided through a signal divider (215, FIG. 6). Each divided signal is then upconverted through a mixer (220) and phase shifted according to the selected orthogonal vector. The resulting signal is then combined through a summing element (250) and transmitted. At a receiver, the incoming signal is coupled to a signal divider (315, FIG. 7) where the signal is divided into N signal components. Each signal component is downconverted and phase shifted so that the transmitted subscriber information can be extracted at a summing element (350). At the summing element (350) the desired subscriber signal components add in-phase while the signal components corresponding to other subscribers add out-of-phase.

Phase domain multiplexed communications system

The invention describes a method and system for channelization through the application of a weighted chirp pulse. The impulse response of a desired filter weighting is applied to the output of a chirp pulse generator (FIG. 1, 150). The resulting weighted chirp pulse is then applied to the a first columnar Bragg cell (80) while an unweighted chirp pulse is applied to a second columnar Bragg cell (90). A modulated energy beam (55) is then allowed to pass through both Bragg cells. The resultant spatially dispersed energy beam (95) is then applied to lens (120) and projected onto a detector array (130). The detector array (130) then extracts the subscriber transmitted information from the projected interference pattern.

Method and system for channelization and down conversion of wideband

A multichannel time shared demodulator (10) is implemented in an efficient ASIC architecture that provides routing-of user voice channels and access channels to a collection of time-shared processors for rapid signal detection, tracking and demodulation. The channels are routed in a random order and then processed by a time-shared symbol synchronization processor (18) for voice channels and a time-shared detection processor for access channels. The signals are over-sampled via a time-shared interpolation filter. The interpolation process yields a ten to one over sampling ration of all signals. A synchronized clock is used to choose the phases of the interpolation filter outputs.

Multichannel time shared demodulator and method

In a satellite communication system, beamforming is performed at baseband frequencies forming only beams which convey information. A received signal is applied to a downconverter (FIG. 1, 30), followed by a channelizer (50), and digital beamformer (60). The order of operations being reversed in order to generate a transmit beam. By performing the beamforming at baseband, the system can be allowed to form only those beams which convey information between a communications node and a subscriber. As a result, the system provides communication services to subscribers in a more cost-effective manner.

Method and system for beamforming at baseband in a communication system

Signal routing from origination nodes (210) to destination nodes (250) in a spread spectrum communication system (100) is provided using spread spectrum routing codes. Origination nodes (210) and destination nodes (250) are identified using specific codes. Signal routes from origination nodes (210) to destination nodes (250) are determined in terms of multi-level paths. Different codes are used to identify the different path levels. Data that is to be sent to a particular user located at a destination node is first spread using the destination code for that destination node. This spread spectrum signal is spread a second time using a first-level path code. In addition, the data can be spread a third time using a second-level path code. During the transmission of the spread data decoding processes are performed and the decoded data is routed based on the results of these decoding processes.

Growing community of inventors

Tempe, AZ, United States of America

James William Startup