National Instruments Corporation

Yong Rao

James Wesley McCoy

Ahsan Aziz

Michael D Cerna

Bin Wang

Lothar Wenzel

Darren R Schmidt

James C Nagle

Subramanian Ramamoorthy

Eckhard Ohlmer

James M Lewis

Kyle P Gupton

Benjamin R Weidman

Naxiong Zhang

A flexible real-time scheduler for a wireless communication node, enabling the node to communicate with a remote node using dynamically variable frame structure. The scheduler continuously receives map information defining the frame structure of frames in a frame sequence. Each frame includes a plurality of slots (e.g., time slots or frequency slots). The map information specifies for each slot of each frame whether the slot is to be a transmit slot or a receive slot. The scheduler drives a transmitter to transmit during the slots assigned for transmission, and drives a receiver to receive during the slots assigned for reception. (The number of slots per frame and the size of each slot are also configurable.)

Flexible real time scheduler for time division duplexing and/or frequency division duplexing

Various embodiments of methods and associated devices for increasing throughput in a programmable hardware element using interleaved data converters are disclosed. A device comprising a programmable hardware element may be configured to comprise a plurality N of processing portions. The device may receive an input signal, and sample the signal in an interleaved fashion, on a per sample basis, at an effective rate K, to produce N parallel data streams. The N parallel data streams may be processed in parallel by the plurality N of processing portions. Outputs of the plurality N of processing portions may be combined to produce output data. The effective rate K and/or the number N of parallel data streams may be specified by user input. Alternatively, these values may be determined automatically. For example, the effective rate K may be determined automatically based on a bandwidth of the input signal.

Systems and methods for high throughput signal processing using interleaved data converters

Techniques are disclosed relating to generating pilot sequences for channel estimation and/or equalization. In some embodiments, a generated pilot sequence has a flat frequency response, a null portion, and low autocorrelation. In some embodiments, a method for generating the pilot sequence includes: starting with a Constant Amplitude Zero Autocorrelation (CAZAC) sequence and iteratively performing, until the result has a flat magnitude: padding the sequence with zeros, determining whether a frequency transform (FT) of the zero-padded sequence has a flat magnitude, adjusting a phase of a second sequence (that has a desired frequency response) to match a phase of the FT, determining an inverse FT of the adjusted second sequence and using a result of the inverse FT as the sequence for the next iteration. The disclosed techniques may allow efficient production of pilot sequences for use in cellular networks, for example.

Pilot sequence design for wireless communications

System and method for computing QR matrix decomposition and inverse matrix R. A circuit is configured to implement a QR decomposition of a matrix A into two matrices Q and R using a Modified Gram Schmidt (MGS) process. The circuit includes a specified portion dedicated to computing matrix Q. Matrix Q is computed via the specified portion based on first inputs using the MGS process, where the first inputs include the matrix A and possibly a scaling factor &#x3c3;. The identity matrix may be scaled by the scaling factor &#x3c3;, thereby generating scaled identity matrix &#x3c3;I. Scaled matrix &#x3c3;R(or unscaled R) may be computed via the specified portion based on second inputs provided to the portion using the MGS process, where the second inputs include the (possibly scaled) identity matrix. If scaled, the scaled matrix &#x3c3;Rmay be unscaled, thereby computing matrix R. Matrix Ris stored and/or output.

Implementing modified QR decomposition in hardware

System and method for developing a circuit for QR decomposition with auxiliary functionality. A first function is included in a first program. The first function is configurable to specify an auxiliary function to be performed by a modified QR decomposition circuit in addition to QR decomposition of a matrix A into two matrices Q and R using a Modified Gram Schmidt process. A second program is automatically generated based on configuration of the QR decomposition and the first function. The second program includes program code implementing the QR decomposition and the auxiliary function for the first function in the first program. A hardware configuration program (HCP) may be automatically generated based on the first program, including the second program, where the HCP is deployable to hardware, e.g., a programmable hardware element, thereby implementing the modified QR decomposition circuit, including the QR decomposition of the matrix A and the auxiliary function.

Software tool for implementing modified QR decomposition in hardware

System and method for approximating a system. A multi-parameter representation of a family of systems is stored. An embedding of the family into an abstract geometrical continuous space with a metric and defined by the parameters is determined. Coordinates of the space specify values for the parameters of systems of the family. The space includes a grid of points representing respective discrete approximations of the systems. A first point corresponding to a desired instance of a system is determined. The first point's coordinates specify values for the parameters of the instance. The space is sampled using a mapping of a well-distributed point set from a Euclidean space of the parameters to the abstract space. A nearest discrete point to the first point is determined which specifies values for parameters for an optimal discrete approximation of the desired instance, which are useable to implement the discrete approximation of the desired instance.

Approximating a system using an abstract geometrical space

System and method for analyzing communication signals. A digital signal comprising multiple samples is received, representing a plurality of binary symbols. Zero crossings of the signal are determined, each comprising a respective first sample immediately preceding the zero crossing and a respective second sample immediately following the zero crossing. Per zero crossing, an error expression is determined interpolating between the first and second samples as a function of estimated period T and estimated offset &#x3c4; of the signal. Based on the error expressions, values of T and &#x3c4; are determined using a linear fit that minimizes a total error of values of the error expressions. T and &#x3c4; are usable in analyzing the signal, e.g., each zero crossing corresponds to a respective symbol represented by a respective segment of the signal. The segments are overlaid based on T and &#x3c4;, forming an eye diagram usable to analyze the signal.

Zero crossing method of symbol rate and timing estimation

A system and method for estimating parameters of multiple tones in an input signal. The method includes receiving samples of the input signal, generating a frequency transform (FT) of the samples, identifying multiple amplitude peaks in the FT corresponding to the tones, and determining parameter estimates characterizing each of the multiple tones based on the peaks. For each tone, the effects of the other tones are removed from the FT of the peak of the tone using the parameter estimates of the other tones to generate modified FT data for the tone. Single tone estimation is applied to the modified FT data to generating refined parameter estimates of the tone, which is used to update the parameter estimates of the tone. After refining the estimates for each tone, the entire process may be repeated one or more times using successive refined estimates to generate final estimates for the parameters.

Estimating a plurality of tones in an input signal

System and method for estimating signal parameters (e.g., frequency, amplitude and/or phase) of one or more tones present in an input signal. Samples of the input signal are received, and a frequency transform of the samples generated. An amplitude peak in the frequency transform corresponding to the tone is identified. Two or more frequency bins are selected proximate to the identified frequency in the transform. A tone frequency value is determined that minimizes a difference between two or more expressions, each including respective numerator and denominator terms corresponding to respective frequency bins and whose ratios each represent a complex amplitude of the tone at a respective bin. Each expressions includes a tone frequency variable that represents a correct tone frequency value of the tone. The correct tone frequency value is determined by computing differences between the expressions for different respective tone frequency variable values, and selecting the value that produces a smallest difference.

Growing community of inventors

Round Rock, TX, United States of America

Yong Rao