| US 7,505,522 B1 | ||
| Spectral shaping in multiband OFDM transmitter with clipping | ||
| Torbjorn A. Larsson, San Diego, Calif. (US) | ||
| Assigned to Staccato Communications, Inc., San Diego, Calif. (US) | ||
| Filed on Oct. 06, 2004, as Appl. No. 10/960,430. | ||
| Claims priority of provisional application 60/508994, filed on Oct. 06, 2003. | ||
| Claims priority of provisional application 60/548547, filed on Feb. 27, 2004. | ||
| Int. Cl. H04L 27/28 (2006.01) | ||
| U.S. Cl. 375—260 [375/261; 375/262; 375/263; 375/264; 375/265; 375/266; 375/267; 375/295; 370/350; 370/503; 370/509; 370/510; 370/511] | 14 Claims |
| 1. A method of shaping an orthogonal frequency division multiplexing (OFDM) signal spectrum, comprising:
receiving an input signal at an interface; and
inserting a modified synchronization sequence in the input signal by a processor to generate an amplitude limited signal that
has a substantially even frequency spectrum; wherein:
the modified synchronization sequence includes one or more reduced spectral peaks in a preamble waveform; and
the modified synchronization sequence was previously derived, including by:
applying a Fourier transform to a synchronization sequence to obtain a plurality of spectral components;
selecting a spectral component from the plurality of spectral components;
determining the clip level relative to the amplitude of the selected spectral component; and
clipping the plurality of spectral components to the clip level.
|