Abstract: A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

Abstract: An uplink power control system for terminals in a satellite communication system provides closed loop power control using feedback signals generated at a satellite. The satellite performs inter-beam routing of uplink signals from satellite terminals, and processing of uplink signals to generate terminal transmission-specific feedback information that is transmitted in downlink signals to the terminals. The satellite also generates a beacon signal. An uplink power control algorithm at each terminal uses the beacon signal and feedback data to adjust transmit power.

Abstract: A system for transmitting data packets over an air interface includes logic for generating a number of redundant packets and parity information. The data packets, redundant packets and parity information may then be transmitted to a distribution device that provides error correction codes. The distribution device may then transmit the data to one or more destinations over an air interface.

Abstract: A communication system balances message traffic between return channel groups and within the groups, so that the user does not control the specific transmission frequency used. Uplink frequencies and bandwidths for the return channels are set by the system in a return channel control message in the broadcast signal so as to account for system and return channel group loading, and to account for user message backlogs. An initial transmission from a remote user may be made using an ALOHA-type burst signal that provides a message backlog to the control station, and is made on a frequency determined from a randomly weighted, load-based frequency selection process. The system, and not the individual users determine the frequency and channel allocations. For large backlogs or priority users, periodic bandwidth is provided.

Abstract: A communication system balances message traffic between return channel groups and within the groups, so that the user does not control the specific transmission frequency used. Uplink frequencies and bandwidths for the return channels are set by the system in a return channel control message in the broadcast signal so as to account for system and return channel group loading, and to account for user message backlogs. An initial transmission from a remote user may be made using an ALOHA-type burst signal that provides a message backlog to the control station, and is made on a frequency determined from a randomly weighted, load-based frequency selection process. The system, and not the individual users determine the frequency and channel allocations. For large backlogs or priority users, periodic bandwidth is provided.

Abstract: A communication system balances message traffic between return channel groups and within the groups, so that the user does not control the specific transmission frequency used. Uplink frequencies and bandwidths for the return channels are set by the system in a return channel control message in the broadcast signal so as to account for system and return channel group loading, and to account for user message backlogs. An initial transmission from a remote user may be made using an ALOHA-type burst signal that provides a message backlog to the control station, and is made on a frequency determined from a randomly weighted, load-based frequency selection process. The system, and not the individual users determine the frequency and channel allocations. For large backlogs or priority users, periodic bandwidth is provided.

Abstract: In a communication system with a bandwidth-on-demand processor, which may be power limited and connected to a myriad of terminals via relatively long delay paths, and another processor, which is connected to a few terminals via relatively short delay paths, an approach for effectively coordinating the processors is disclosed. A bandwidth controller receives a message requesting bandwidth from a remote processor and selectively grants the bandwidth request. The bandwidth controller transmits an assignment message that specifies a bandwidth allocation to the remote processor, and concurrently transmits a control message. A switch is configured to forward the assignment message to the remote processor. A controller is coupled to the switch and is configured to receive the control message, wherein the control message provides bandwidth allocation. The above arrangement has particular applicability to a satellite communications system.

Abstract: A satellite communications system having a fallback mode of operation, during which uplink signals are transmitted at a reduced data rate, is provided with a novel fallback mode ingress/egress mechanism utilizing a combination of a feedback-based fade detection scheme and fade detection based on parameters independent of the uplink signal transmission. The fallback mode ingress/egress mechanism is responsive to a satellite beacon signal independent of the uplink signals and to feedback signals produced by the satellite in response to the uplink signals, for requesting a satellite terminal to switch into the fallback mode when either the feedback signals indicate an increase in a fade level or in response to a first value of a selected parameter of the satellite beacon signal. The fallback mode ingress/egress mechanism requests the satellite terminal to switch out of the fallback mode in response to a second value of the satellite beacon signal parameter.

Abstract: The present invention relates to a method and apparatus of using ephemeris data for positioning of an antenna of an earth station. Ephemeris data is transmitted from the satellite to the earth station, wherein the ephemeris data comprises positioning data of a satellite. The ephemeris data is received by the earth station and is used to realize the location of the satellite. The antenna of the earth station is adjusted to point toward the satellite, using the received ephemeris data.

Abstract: An antenna of an earth station is adjusted at a predetermined interval for calibration purposes. A notification of clear sky is received. Signals from a satellite are received upon the receiving of the notification of clear sky. The antenna of the earth station is adjusted to point in various directions while receiving the signals from the satellite. A direction is determined where the antenna of the earth station is pointing where the strongest signal is received from the satellite. The antenna of the earth station is positioned to point in the direction where the strongest signal is received by the satellite.

Abstract: An uplink power control system for terminals in a satellite communication system provides closed loop power control using feedback signals generated at a satellite. The satellite performs inter-beam routing of uplink signals from satellite terminals, and processing of uplink signals to generate terminal transmission-specific feedback information that is transmitted in downlink signals to the terminals. The satellite also generates a beacon signal. An uplink power control algorithm at each terminal uses the beacon signal and feedback data to adjust transmit power.

Abstract: A communications system includes a base station that is configured to transmit a signal that is modulated according to a predetermined modulation scheme and an orthogonal frequency division multiplexing scheme, wherein the signal is encoded using space-frequency coding. The base station includes a plurality of multiple-input multiple-output (MIMO) transceivers. The system includes a terminal that is configured to receive the modulated signal. The above arrangement is particularly applicable to providing multichannel multipoint distribution services (MMDS) over a radio communications system.

Abstract: In a communication system with a bandwidth-on-demand processor, which may be power limited and connected to a myriad of terminals via relatively long delay paths, and another processor, which is connected to a few terminals via relatively short delay paths, an approach for effectively coordinating the processors is disclosed. A bandwidth controller receives a message requesting bandwidth from a remote processor and selectively grants the bandwidth request. The bandwidth controller transmits an assignment message that specifies a bandwidth allocation to the remote processor, and concurrently transmits a control message. A switch is configured to forward the assignment message to the remote processor. A controller is coupled to the switch and is configured to receive the control message, wherein the control message provides bandwidth allocation. The above arrangement has particular applicability to a satellite communications system.

Abstract: A combined interference cancellation communication system employing forward error code (FEC) decoding for high spectral efficiency satellite communications. The disclosed system enables efficient utilization of available bandwidth through overlapping adjacent channels. A receiver is used to receive a waveform having data information and noise information. A filter bank is coupled with the receiver to receive and filter waveform and output channel information received by the receiver. The channel information received includes a combination of data signals and adjacent channel interference signals. A demodulator is provided to provide an estimation signal representative of an estimation of at least one parameter of the channel information. Soft-input and soft-output decoders are provided to receive the channel information in order to calculate and estimate interference values based on the estimation signal.

Abstract: An RF emission hazard zone of an RF transceiver is controlled to ensure that RF energy density limits for humans is not exceeded when a human body part enters the RF hazard zone near an antenna reflector and feedhorn. In a first aspect, a transmitter duty cycle is reduced to effectively reduce the average power transmitted from the antenna whenever a signal level of a received signal is reduced below a threshold value. The reduction in average transmitter power reduces the RF emission hazard zone near the antenna, and limits the exposure of any person who has intruded into the hazard zone. In a second aspect, the transmitter is disabled whenever a received signal is affected so that signal quality, bit-energy-to-noise ratio (Eb/No), synchronized state in a demodulator, lock condition in a FLL, or received signal strength are degraded, indicating that a human has intruded into the RF hazard zone.