US 12,283,996 B1
Efficient nonlinear equalizer for transmitter predistortion
Hongbin Zhang, Holmdel, NJ (US); Sheng Zhang, Morganville, NJ (US); and Tymon Barwicz, Holmdel, NJ (US)
Assigned to CISCO TECHNOLOGY, INC., San Jose, CA (US)
Filed by Cisco Technology, Inc., San Jose, CA (US)
Filed on Jan. 19, 2023, as Appl. No. 18/098,764.
Int. Cl. H04B 10/588 (2013.01)
CPC H04B 10/588 (2013.01) [H04B 2210/254 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method comprising:
mapping a symbol from an optical N-QAM (quadrature amplitude modulation) constellation into a binary bit set; wherein N is the number of symbols in the constellation;
reducing a length of the binary bit set; wherein the reduction is performed according to at least one property of nonlinear distortion;
generating a lookup table (LUT) address from a LUT address generator; and
adding the LUT address to a LUT of size smaller than N (2M+1); wherein 2M is the number of neighboring symbols to be stored.