Analog Devices,inc.

Massachusetts Institute of Technology

Boston University

Nationaluniversity of Ireland, Maynooth

Wei An

Yosef Stein

Richard P Schubert

Haim Primo

Mariko Medlock

Muriel Medard

Kenneth R Duffy

Amit Solomon

Brian Reggiannini

Rabia Tugce Yazicigil Kirby

Vaibhav Bansal

Josef Stein

Described is a decoder suitable for use with any communication or storage system. The described decoder has a modular decoder hardware architecture capable of implementing a noise guessing process and due to its dependency only on noise, the decoder design is independent of any encoder, thus making it a universal decoder. Hence, the decoder architecture described herein is agnostic to any coding scheme.

Universal guessing random additive noise decoding (GRAND) decoder

A receiver apparatus models and corrects the frequency-dependent and the frequency-independent mismatches between I and Q paths jointly by polynomial estimations. The receiver apparatus may sample digitized I and Q path signals. The sampled data point may be modeled in equations with real and imaginary components. The sampled discrete time-domain data may be converted to frequency-domain data. Multiple statistics values based on the frequency-domain data may be computed. Coefficients for the polynomial equations may be estimated based on the computed statistic values. The channel mismatches may be estimated from the polynomial equations and used to compensate the mismatch either on the I path or the Q path.

Real-time I/Q imbalance correction for wide-band RF receiver

In an example, there is disclosed a system and method for detecting and correcting error in a quadrature receiver (QR). The QR may include a receiver channel operable to divide a received RF signal into I and Q channels. The receiver channel may include error sources, such as (in sequence) pre-demodulation (PD) error, LO mixer error, and baseband (BB) error. Test tones may be driven on the receiver channel at a plurality of test frequencies, and a quadrature error corrector may be provided to detect error from each source. Upon receiving an RF signal, the quadrature error corrector may apply correction coefficients to correct each source of error in reverse sequence (BB, LO, PD).

Quadrature error detection and correction

System and method quadrature error detection and correction

Apparatus and method for quadrature error correction for narrowband or tone signal are disclosed. An analog circuit receives a modulated signal and processes in-phase signal and quadrature-phase signal in in-phase and quadrature-phase signal paths respectively. A digital signal processor performs discrete Fourier transform on each of the in-phase and quadrature-phase signals and determines statistical parameters responsive to mismatch characteristics to estimate quadrature error correction.

Systems and methods for narrowband signal quadrature error correction

One example embodiment provides a system, apparatus, and method for using polynomial models in tone calibration for quadrature error correction in I/Q receivers. In one example embodiment, method for calibrating an I/Q receiver is provided and includes receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.

Quadrature error correction using polynomial models in tone calibration

A receiver architecture for processing spread spectrum signals. The receiver has an RF front end to receive and down convert a broadcast signal to an intermediate frequency carrier. The IF signal is digitized and provided to a processor (which may be a software-driven DSP, an ASIC or other embodiment) for processing. A given IF carrier is removed and the signal is low pass filtered. The signal is provided to a number of channels, each, for example, correspond to a unique transmitter. On each channel the sample rate is reduced to a predetermined fixed rate with timing mismatch compensated. The Doppler frequency shift, as estimated for the channel, is removed succeedingly. A locally generated copy of the spreading code used by the transmitter is applied to the carrier and Doppler removed signal at the predetermined fixed sample rate. The de-spread signal is used to provide estimates of the Doppler shift and for subsequent sample selection. Pseudo-range and delta pseudo-range estimates from each channel are used to estimate, for example, the receiver's position.

Method and apparatus for software GPS receiver

Channel estimation for high mobility OFDM channels is achieved by identifying a set of channel path delays from an OFDM symbol stream including carrier data, inter-channel interference noise and channel noise; determining the average channel impulse response for the identified set of channel path delays in each symbol; generating a path delay curvature for each channel path delay in each symbol based on stored average channel impulse responses for the identified channel path delays; estimating the carrier data in the symbols in the OFDM symbol stream in the presence of inter-channel interference noise and channel noise from the OFDM symbol steam and the average impulse responses for the identified channel path delays; reconstructing the inter-channel interference noise in response to the path delay curvature, the identified set of channel path delays and estimated carrier data to produce a symbol stream of carrier data and channel noise with suppressed inter-channel interference noise.

OFDM channel estimation system and method components

The problem of inefficient channel impulse-response processing is addressed by processing different parts of a channel impulse response to accurately locate channel taps, and to generate more than one set of equalization coefficients. This allows the most-suited equalization coefficient to be selected based on a selection criterion.

Equalization for OFDM communication

Channel estimation for high mobility OFDM channels is achieved by identifying a set of channel path delays from an OFDM symbol stream including carrier data, inter-channel interference noise and channel noise; determining the average channel impulse response for the identified set of channel path delays in each symbol; storing the average channel impulse responses for the identified channel path delays; generating a path delay curvature for each channel path delay in each symbol based on stored average channel impulse responses for the identified channel path delays; estimating the carrier data in the symbols in the OFDM symbol stream in the presence of inter-channel interference noise and channel noise from the OFDM symbol stream and the average impulse responses for the identified channel path delays; reconstructing the inter-channel interference noise in response to the path delay curvature, the identified set of channel path delays and estimated carrier data; and subtracting the reconstructed inter-channel interference noise from the OFDM symbol stream to produce a symbol stream of carrier data and channel noise with suppressed inter-channel interference noise.

Channel estimation system and method

A method of generating a pseudo-noise sequence without masking a linear feedback shift register (LFSR) generator is provided. An offset pseudo-noise sequence is generated at a desired offset from a reference psuedo-noise sequence by determining a corresponding initial state vector of the LFSR based on an arbitrary mask.

Growing community of inventors

Newton, MA, United States of America

Wei An