Delphi Technologies, Inc.

Eric A Dibiaso

Glenn A Walker

Michael L Hiatt, Jr

Jeffrey J Marrah

Jerral A Long

Timothy David Bolduc

Larry J Fruit

J Robert Dockemeyer, Jr

Michael L Hiatt

Michael L Hiatt Jr

A system and method of communicating signals is provided. The system includes a plurality of satellites, at least one receiver, and at least one satellite uplink station. The plurality of satellites include at least one active satellite. The at least one receiver is in communication with the plurality of satellites, and receives a signal from the at least one active satellite. The at least one satellite uplink station is in communication with the plurality of satellites, and transmits the signal and alters a frequency of the signal based upon a location of the at least one active satellite to reduce a Doppler frequency shift when activating and deactivating the plurality of satellites.

System and method of satellite communication that reduces the doppler frequency shift of the satellite signals

A system and method of multi-source communications, including a source provider, a transmitter, a receiver, a summing device, a plurality of delay devices, and a switch. The source provider provides a signal including a first and second signal. The transmitter is in communication with the source provider and the receiver. The receiver is in communication with the transmitter. The summing device combines the first and second signals received by the receiver. The delay device delays at least one of the first and second signals. The switch forms a bypass, such that at least one of the first and second signals bypasses one of the plurality of delay devices.

System and method for multi-source communications

A system and method of communicating sub-synchronization information into a transmitted digital audio stream and extracting sub-synchronization information from a received digital audio stream is provided. The method includes the steps of having a transmitter introduce sub-synchronization information into a data stream at a period less than that of existing transmitter pre-amble signals, and transmitting that data to a receiver. The method further includes the steps of receiving the transmitted data stream in the receiver circuitry, extracting the synchronization information, and using the synchronization information to accurately decode the received audio data.

Method and system for communicating sub-synchronization signals using a phase rotator

A receiver system and method for switching among a plurality of antenna elements to receive a signal. At least a portion of plurality of antenna elements receive a transmitted signal, such that the transmitted signal includes a plurality of sub-channels that are transmitted in predetermined time intervals. A switching device is in communication with the plurality of antenna elements, and switches among single antenna elements to receive the transmitted signal. A controller is in communication with the switching device, and commands the switching device to select each of the antenna elements separately in predetermined periods of time based upon the predetermined time intervals of each of the sub-channels. A power level of the transmitted signal is determined during the predetermined period of time that corresponds to the predetermined time intervals, and the controller commands the switching device to switch to an antenna element based upon the determined power level.

Receiver system and method for switching among a plurality of antenna elements to receive a signal

High priority data and low priority digital data are transmitted as primary and secondary data in hierarchically modulated, orthogonal frequency division multiplexing (OFDM) from an earth-orbiting satellite. To enable the transmitter amplifier to be operated with less back-off from saturation without clipping, the low priority OFDM symbols have fewer samples than the high priority OFDM symbols, and the high priority samples on which the low priority samples are superimposed are selected according to a first deterministic rule using sample power comparisons of the high priority samples to concentrate the low priority samples on those high priority samples having lower (optimally, the lowest) sample power. The low priority samples are distributed on the selected high priority samples according to a second deterministic rule relating the original low priority sample order to the original high priority sample order.

Hierarchically modulated OFDM communication from a satellite-based transmitter with reduced secondary data loss from clipping

A communication system and method of communicating signals to a plurality of different types of receivers is provided. At least one transmitter transmits hierarchically modulated high priority and low priority signals as a single frequency network. At least one satellite re-transmits the high priority signal in a first circularly polarized direction and the low priority signal in a second circularly polarized direction. At least one of a first receiver having a single antenna is configured to receive the high priority signal in the first circularly polarized direction and switched to receive the low priority signal in the second circularly polarized direction, and a second receiver having a first antenna is configured to receive the high priority signal in the first circularly polarized direction, and a second antenna is configured to receive the low priority signal in the second circularly polarized direction substantially simultaneously.

Communication system and method for receiving high priority and low priority signals

A communication system and method of communicating signals to a plurality of different types of receivers is provided. The communication system includes at least one transmitter that transmits a high priority signal and a low priority signal that are hierarchically modulated and transmitted as a single frequency network. At least one satellite receives and re-transmits at least one of the high priority and low priority signals. At least one of the plurality of receivers include a processor that performs the steps of storing the hierarchically modulated signal, demodulating the high priority signal from the hierarchically modulated signal, decoding the demodulated high priority signal, re-encoding the high priority signal, and processing the stored hierarchically modulated signal based upon the re-encoded high priority signal.

Communication system and method of receiving high priority signals and low priority signals

The present invention provides a method to minimize degradation in a D-MPSK hierarchical modulation system by adding additional data throughput (i.e., secondary information) as an offset to the primary signal transmitted by a SDARS terrestrial repeater. The present invention provides techniques for adding the additional throughput as Level 2 data by transmitting offset phase and/or amplitude information across adjacent OFDM symbols and/or adjacent frequency subcarriers.

Method to minimize degradation in a D-MPSK hierarchical modulation system

Additional data may be added to the current SDARS satellite signals as a phase and/or amplitude offset from the legacy quadrature phase shift keying (QPSK) modulated data and transmitted by the SDAR terrestrial repeaters. However, in the case where a legacy receiver architecture for a differential modulation system outputs angular/phase differences between carriers, the phase and/or amplitude information appears as distortion to the legacy receiver. The present invention provides a method for optimizing the SDARS infrastructure more efficiently by allowing independent adjustment of the phase and/or amplitude offset () at each terrestrial site. The present invention provides a method for adjusting the performance of each signal together or separately as needed.

Method to enable single frequency network optimization

Where the additional data throughput is added using an amplitude offset or a combination of phase and amplitude offset, the legacy differential demodulator does not recover the amplitude information. The present invention provides a method for demodulating amplitude offsets in a differential modulation system in order to recover the amplitude information. The demodulated amplitude information may be used to recover the additional Level 2 data transmitted as an amplitude offset or combination phase and amplitude offset in a differential multiple phase shift keying (D-MPSK) transmission, such as across adjacent OFDM symbols and/or adjacent frequency subcarriers.

Method to demodulate amplitude offsets in a differential modulation system

The present invention provides a method, receiver and transmitter for use in a SDAR system. The method involves generating a first modulated signal based on first input data. Additional modulation is superimposed on the first modulated signal based on additional input data, being spread across a plurality of symbols in the first modulated signal in a predetermined pattern to generate a modified signal which is then transmitted. The modified signal is decoded by performing a first demodulation of the first modulated signal then additional demodulation is performed to obtain additional input data. The superimposing step uses a plurality of offset sequence values to add the additional modulation to the first modulated signal. The offset sequence may appear as a pseudo-random distribution of offset sequence values, and may include at least one zero offset value. Alternatively, the additional modulated signal may be a formed as a direct sequence spread spectrum modulation and the offset sequence appearing as a pseudo-noise distribution. A Hadamard matrix sequence may be used as the direct sequence code.

Method to minimize compatibility error in hierarchical modulation using variable phase

The present invention involves a method for transmitting data within a specified band of allocated spectrum in a satellite digital transmission system. First a data stream is encoded according to a first encoding scheme, then a second data stream is generated according to a second encoding scheme. The second encoding scheme is incompatible with the first encoding scheme. The first and second data streams are transmitted at predetermined locations within the specified band, such as time slices within a time division multiplexing transmission system. The second data stream is generated by using a more efficient FEC algorithm, including turbo-convolutional, turbo-product, low density parity check, or repeat-accumulate encoders. The inventive receiver has an antenna for receiving RF signals and a demodulator coupled to the antenna for downconverting received RF signals into a data stream. A splitter then separates the data stream into first and second component data streams. A first detector is coupled to the splitter, and is adapted to detect data in the first format. A second detector is coupled to the splitter, and is adapted to detect data in the second format.

Method and system to increase available bandwidth in a time division multiplexing system

This invention provides a receiver for use in a SDAR system which includes a receiving unit having satellite signal detection means for detecting a first transmit signal transmitted from a first communication satellite and a second transmit signal transmitted from a second communication satellite, the first transmit signal produced when the transmitter modulates a primary data stream with a secondary data stream on a first carrier wave associated with the first communication satellite and the second transmit signal produced when the transmitter modulates the primary and secondary data streams on a second carrier wave associated with the second communication satellite, and an encoder re-encodes the primary and the secondary data on a third carrier wave, forming a third transmit signal which is re-transmitted to a receiver using a terrestrial repeater. This invention also provides a method of receiving transmitted data.

Method to increase performance of secondary data in a heirarchial modulation scheme

The present invention provides a method of hierarchically modulating first and second digital data streams in a broadcast system such as an SDAR system that is compatible with legacy receivers. The second digital data stream, but not the first, is provided with a non-binary pseudo-random encoding. A carrier is first modulated, e.g. QPSK, by the first digital data stream; and a second modulation is performed with the encoded second digital data stream. The encoding includes a multiplication of a matrix formed of 2, 3 or 4 consecutive bits of the secondary data stream by a matrix, e.g. a Hadamard matrix to form a product matrix having non-binary values that are used to modify consecutive symbols of the first modulation. The second modulation appears as Gaussian noise to legacy receivers over time.

The present invention generally relates to the transmission of digital data, and more particularly, to the transmission of digital data in a satellite digital audio radio ('SDAR') system. In the SDAR system, there may be different types of required services. Some of these services may be considered high priority and others may be of a lower priority. Current SDAR systems have the same performance on all user data. Therefore, there is a need to vary the performance of different services. The present invention provides a method and apparatus for optimizing the throughput (i.e. information) in a digital transmission system by transmitting the different services with different performance levels. The present invention addresses the need in the art to vary the performance of different services (i.e., levels of data). Because the performance of the primary level of data will not be equal to the performance of the secondary level of data, the primary level will need to be further protected. The primary level data may be streaming data. The secondary level data does not need as much protection because it may be rebroadcast repeatedly. The easiest and most cost effective solution is to integrate multiple symbols for a secondary level bit. The present invention provides a method and apparatus in which the power level for the data levels can be set within each data packet using a message header providing the different services with different levels of performance.

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Kokomo, IN, United States of America

Eric A Dibiaso