A method, apparatus and computer program product for performing decimated correlation in a wireless communications network is disclosed. An input signal composed of a plurality of streaming samples of the input signal is received and applied to a plurality of shift registers coupled to computation logic. The computation logic receives an input of correlation options and a correlation pattern. Based upon a comparison to a correlation threshold, the correlator selectively holds the correlation options constant to inhibit a new correlation, and/or selectively freezes streaming samples input to the computation logic via a plurality of corresponding shadow registers to save power.

Example communication systems and methods are described. In one implementation, a method receives a first chaotic sequence of a first temporal length, and a second chaotic sequence of a second temporal length. The method also receives a data symbol for communication to a destination. Based on the data symbol, the second chaotic sequence is temporally shifted and combined with the first chaotic sequence to generate a composite chaotic sequence. The first chaotic sequence functions as a reference chaotic sequence while the second chaotic sequence functions as a data-carrying auxiliary chaotic sequence.

A radar system processes signals in a flexible, adaptive manner to determine range, Doppler (velocity) and angle of objects in an environment. The radar system processes the received signal to achieve different objectives depending on one or more of a selected range resolution, a selected velocity resolution, and a selected angle of arrival resolution, as defined by memory requirements and processing requirements. The system allows improved resolution of range, Doppler and/or angle depending on the memory requirements and processing requirements. The system also adapts to changing environmental conditions including interfering radio signals.

A radio frequency (RF) communications system may include a first RF node that transmits data, including a new frequency of operation, and a sequence of pilot symbols spread with a complex spreading code sequence. A second RF node may receive an incoming signal from the first RF node and perform despreading for N sample offset delays to generate N despreading sequences for the sequence of pilot symbols. The second RF node may perform a cross-correlation to select a desired despreading sequence from the N despreading sequences, determine a phase offset and timing offset, process the incoming signal based upon the desired despreading sequence, phase offset and timing offset, and switch to the new frequency of operation.

A correlation apparatus including a sequence generator configured to generate a non-repeating preamble sequence which changes during each of a plurality of time epochs. The correlation apparatus includes a fallthrough correlator having a tapped delay line for receiving a set of complex-valued samples of a received signal. Each of a plurality of complex multipliers of the correlator is coupled to one of the delay line taps. Each multiplier multiplies, during one of the plurality of time epochs, one of the complex-valued samples of the received signal by one of a plurality of matched filter coefficients corresponding to the preamble sequence. A summation module includes a plurality of adders where a last of the plurality of adders outputs a correlation signal. A peak value of the correlation signals exceeds a threshold value when a sufficient correlation exists between the received signal and the values of the preamble sequence.

A signal receiver for receiving a HOPS-based communications signal includes a seed calculator configured to produce a series of seed vectors generated from a corresponding series of sets of key values. A sequence generator provides a series of internally generated sequences using the series of seed vectors. A fallthrough correlator produces a series of correlation values by correlating samples of a received signal and samples of the internally generated sequences. The spreading sequences are used by a transmitter to generate a transmit signal subsequently received as the received signal. A peak detector is configured to generate a trigger signal upon determining that at least one of the correlation values exceeds a threshold value. At least one of a plurality of demodulator chains is selected in response to the trigger signal and used to demodulate the received signal in order to recover data values carried by the received signal.

A radar sensing system for a vehicle includes a transmit pipeline, a receive pipeline, and a memory module. The transmit pipeline includes transmitters for transmitting radio signals. The receive pipeline includes receivers for receiving radio signals that include the transmitted radio signals transmitted by the transmitters and reflected from objects in an environment. The memory module is configured to store interference estimates for each receiver of the plurality of receivers that are estimates of interfering radio signals received by each of the receivers that are transmitted by each respective transmitter of the plurality of transmitters. Each receiver of the plurality of receivers is configured to mitigate interference that is due to interfering radio signals transmitted by the plurality of transmitters, as defined by the stored interference estimates of the plurality of transmitters for each particular receiver.

A Global Navigation Satellite System receiver for position determination receives from a multitude of satellites a respective GNSS code signal, which are correlated with a reference code signal to obtain an autocorrelation function. A multitude of function values of the autocorrelation function at different discrete chip spacings (chosen asymmetrically with respect to a prompt chip spacing) are analyzed and used in obtaining a test metric. Using the test metric, a decision is made whether the received GNSS code signal is suitable or unsuitable (thereafter excluded) for a position determination due to multipath signal components. A bias removal is performed taking into account corresponding function values of an autocorrelation function that would result from a received GNSS code signal of the satellite unaffected by multipath signal components. This provides a simple method for operating a GNSS receiver minimizing errors in position determination caused by multipath signal components.

A receiver for spread spectrum signals comprising a first part for preprocessing and digitizing a received signal, and a second part for tracking the digitized signal comprising a carrier loop and a code loop. The code loop comprises a generator for a reference receiver signal for correlation with the received signal and the code loop is configured to modify the reference signal to shape a correlation function between the received signal and the reference receiver signal. The first part is adapted to multiply the received spread spectrum signal with a first analog spectral offsetting signal provided for down-converting the received signal to an intermediate frequency and a sub-carrier frequency, selected from a set of sub-carrier frequencies, such that the received signal is down-converted and spectrally offset in the analog domain during a time interval covering at least one chip of a spreading code of the received signal.

A radar system processes signals in a flexible, adaptive manner to determine range, Doppler (velocity) and angle of objects in an environment. The radar system processes the received signal to achieve different objectives depending on one or more of a selected range resolution, a selected velocity resolution, and a selected angle of arrival resolution, as defined by memory requirements and processing requirements. The system allows improved resolution of range, Doppler and/or angle depending on the memory requirements and processing requirements.