System and method for communicating data using efficient fast fourier transform (FFT) for orthogonal frequency division multiplexing (OFDM) modulation
US8229009B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 2008 |
| Grant date | Jul 24, 2012 |
| Priority date | — |
| Expiry date | Mar 28, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/265
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A communications device includes at least one memory device for storing complex exponential functions as approximations of sine and cosine basis waveforms. A logic circuit adds and subtracts the complex exponential functions to generate an Orthogonal Frequency Division Multiplexed (OFDM) communications signal as a plurality of N data subcarriers that carry communications data. The logic circuit provides efficient and accurate implementation of the IFFT for use as an OFDM modulator using additions of stored complex exponentials and modulation of the integer-valued QAM data symbols using logic shifts and sign changes (2's complement).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.