Abstract: A signal to interference-plus-noise power ratio (SINR) measurement method for wireless communications systems which employ orthogonal frequency division multiplexing (OFDM) for multicarrier data transmission is disclosed. Fast-Fourier transform (FFT)-based SINR measurements can be computed on frame-by-frame or greater interval for individual or groupings of subchannel signals. Given a known transmitted time-domain OFDM frame preamble, and the corresponding channel and interference-plus-noise (IPN) corrupted received time-domain frame preamble, the disclosed method first computes the power spectral densities of the received signal of interest and of a received unwanted interference-plus-noise signal. The FFT-computed power spectral densities are then used to compute average received signal and received IPN power measurements for specified individual or groupings of OFDM subchannel signals. The power measurements are then frame-averaged using a recursive exponential smoothing method.

Abstract: A nonlinear signal mapper that can implement any continuous one-to-one nonlinear map of baseband or intermediate-frequency digital signals. The mapping method follows a “divide-and-conquer” approach in that a nonlinear map to be implemented is piecewise decomposed into a set of simpler nonlinear component maps. The component maps are implemented using code-enabled feed-forward neural networks (FF-NNs). Each code-enabled feed-forward neural network only operates on samples of a digital input signal that lie in a specified interval of the real-valued number line. Code-enabled FF-NNs are controlled by codewords produced by a scalar quantization encoder. The quantization encoder also controls a multiplexer that directs values produced by the FF-NNs to the nonlinear mapper's output.

Abstract: A signal to interference-plus-noise power ratio (SINR) measurement method for wireless communications systems which employ orthogonal frequency division multiplexing (OFDM) for multicarrier data transmission is disclosed. Fast-Fourier transform (FFT)-based SINR measurements can be computed on frame-by-frame or greater interval for individual or groupings of subchannel signals. Given a known transmitted time-domain OFDM frame preamble, and the corresponding channel and interference-plus-noise (IPN) corrupted received time-domain frame preamble, the disclosed method first computes the power spectral densities of the received signal of interest and of a received unwanted interference-plus-noise signal. The FFT-computed power spectral densities are then used to compute average received signal and received IPN power measurements for specified individual or groupings of OFDM subchannel signals. The power measurements are then frame-averaged using a recursive exponential smoothing method.

Abstract: A nonlinear signal mapper that can implement any continuous one-to-one nonlinear map of baseband or intermediate-frequency digital signals. The mapping method follows a “divide-and-conquer” approach in that a nonlinear map to be implemented is piecewise decomposed into a set of simpler nonlinear component maps. The component maps are implemented using code-enabled feed-forward neural networks (FF-NNs). Each code-enabled feed-forward neural network only operates on samples of a digital input signal that lie in a specified interval of the real-valued number line. Code-enabled FF-NNs are controlled by code-words produced by a scalar quantization encoder. The quantization encoder also controls a multiplexer that directs values produced by the FF-NNs to the nonlinear mapper's output.