Patent ID: 9559815
Date: 2017-01-31
CPC Classifications: H04L

Claim:
1. A method for generating a modified orthogonal frequency division multiplexing (OFDM) symbol, the method comprises: receiving OFDM symbol constellation samples of the OFDM symbol; wherein the OFDM symbol constellation samples belong to a given constellation; searching, in the OFDM symbol constellation samples, for outer OFDM symbol constellation samples that are located on a boundary of the given constellation; converting the OFDM symbol constellation samples to time-domain OFDM (TDOS) samples; searching for residual TDOS samples that have an intensity that exceed an intensity threshold; calculating, for each residual TDOS sample, a residual error; wherein the residual error has a phase that equals a phase of the residual TDOS sample and an amplitude that equals a difference between an amplitude of the residual TDOS sample and the intensity threshold; converting the residual errors to frequency domain residual (FDR) errors; calculating, for each outer OFDM symbol constellation sample, an expansion vector that represents an expansion of the given constellation at the outer OFDM symbol constellation sample; generating, for each pair of FDR error and outer OFDM symbol constellation sample that belong to a same sub-carrier, a modified OFDM symbol constellation sample thereby providing multiple modified OFDM symbol constellation samples; and calculating the modified OFDM symbol; wherein the calculating of the modified OFDM symbol comprises performing a frequency domain to time domain conversion of (a) the multiple modified OFDM symbol constellation samples and (b) unmodified OFDM symbol constellation samples; and wherein for each outer OFDM symbol constellation sample the expansion vector starts from the outer OFDM symbol constellation sample and expands outwards from the OFDM symbol constellation at a direction that does not reduce a distance between any OFDM sample constellation samples, including modified OFDM symbols.