Delphi Technologies, Inc.

Michael L Hiatt, Jr

Glenn A Walker

Eric A Dibiaso

Eric A DiBIASO

Roger A McDanell

Jerral A Long

Joseph R Dockemeyer, Jr

Harry Diamond

Linda L Miner

A method is presented to extend a frequency lock range of a received RF signal in a satellite receiver. One step in the method includes analyzing data information of a preamble associated with the received satellite RF signal. Another step includes determining an estimated frequency value that is a function of the analyzed data information that further includes at least a portion of the frequency error formed therein. A further step includes comparing the determined estimated frequency value to a predetermined threshold value. Another step includes using the determined estimated frequency value when the determined frequency value is greater than the predetermined threshold value to operatively control tracking mode electronic circuitry disposed in the satellite receiver to attain frequency lock on the received satellite RF signal.

Methods to extend the frequency lock range of a received RF signal using a preamble-based frequency estimate

Long time interleaver and listenable audio performance enhancements for a satellite receiver are presented. One enhancement includes comparing a correlation and a predetermined threshold value and blocking satellite signal data transmission from entry into long time interleaver (LTI) device circuitry and forward error correction (FEC) circuitry when the correlation value is the same as, or less than the predetermined threshold value. Another enhancement includes using Reed-Solomon codeword error checking to prevent erroneous baseband signal data from being accepted as good baseband signal data. A further enhancement includes storing symbol timing and frequency data during a strong signal condition of the satellite receiver and using this stored data when the satellite receiver encounters a weak signal condition. Another enhancement includes mitigating DC offset noise in a satellite receiver having a zero-IF tuner.

Satellite receiver performance enhancements

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

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

A method and system for communicating satellite digital radio program information for multiple satellite channels is provided. The method includes the steps of providing multiple satellite signals, and providing multiple data frames in each of the satellite signals. The method also includes the steps of providing frame synchronization symbols in each of the data frames, such that the frame synchronization symbols occurring in the satellite signals do not overlap in time with each other. The method also includes the steps of providing multiple data slots within each of the data frames, and providing satellite program information in at least one of the data slots in each data frame. The multiple data slots are positioned within each data frame relative to the frame synchronization symbol of that data frame, such that the data slots containing satellite program information in the multiple satellite signals do not overlap in time with each other.

Method and system for sending and receiving satellite digital radio programming information for multiple channels

Multiple receivers may be enabled to receive satellite-based digital audio radio (SDAR) services under a single subscription. For example, an SDAR service provider can enable multiple vehicles, a home-based digital radio, or a portable digital radio, singly or in any combination. Multiple receivers transmit information to each other. One receiver is designated as a primary receiver, and the other receivers are designated as secondary receivers. The SDAR service provider transmits a list of associated secondary receivers to the primary receiver. The primary receiver enables the associated secondary receivers to receive SDAR services by placing them in an authorized state. The secondary receivers must periodically communicate with the primary receiver to remain authorized. A secondary receiver that fails to communicate with the primary receiver within a prescribed time period is switched to an unauthorized state. In this unauthorized state, the secondary receiver no longer performs as an authorized receiver.

Communication service subscription management

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

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.

Method for variable performance in communication systems

The present invention involves a method for transmitting data having primary and secondary data. A first transmit signal is transmitted from a first communication satellite wherein the first transmit signal is produced when the transmitter modulates the primary and secondary data on a first carrier wave associated with the first communication satellite, with secondary data having a first polarity. A second transmit signal is transmitted from a second communication satellite wherein said second transmit signal is produced when the transmitter modulates the primary and secondary data on a second carrier wave associated with the second communication satellite with secondary data having a second polarity opposite the first polarity.

Method to optimize hierarchical modulation for a diversity system

A technique for demodulating secondary data from a hierarchically modulated signal includes a number of steps. A gray coded eight phase shift key (8-PSK) hierarchically modulated signal is received that includes primary data and secondary data. An imaginary portion of the signal is determined and a real portion of the signal is determined. An absolute value of the real portion of the signal may then be subtracted from an absolute value of the imaginary portion of the signal to provide the secondary data. The gray coded 8-PSK hierarchically modulated signal may be a uniform gray coded 8-PSK hierarchically modulated signal or a non-uniform gray coded 8-PSK hierarchically modulated signal.

Technique for demodulating level II hierarchical data

The present invention provides a receiver for use in a SDAR system, the receiver including a receiving unit having satellite signal detection means for detecting a transmit signal transmitted from a satellite, the transmit signal produced when the transmitter modulates a primary data stream with a secondary data stream on a carrier wave associated with the satellite; and at least one demodulator coupled to the receiving unit and configured to demodulate the transmit signal.

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Westfield, IN, United States of America

Michael L Hiatt, Jr