US 7,469,019 B2
Optimization technique for layered modulation
Weizheng Wang, Rancho Palos Verdes, Calif. (US); Guangcai Zhou, Reseda, Calif. (US); Tung-Sheng Lin, Alhambra, Calif. (US); Ernest C. Chen, San Pedro, Calif. (US); Joseph Santoru, Agoura Hills, Calif. (US); and William C. Lindsey, Pasadena, Calif. (US)
Assigned to The DIRECTV Group, Inc., El Segundo, Calif. (US)
Filed on Jan. 18, 2007, as Appl. No. 11/655,001.
Application 11/655001 is a continuation of application No. 10/693140, filed on Oct. 24, 2003, granted, now 7,184,489.
Application 10/693140 is a continuation in part of application No. 09/844401, filed on Apr. 27, 2001, granted, now 7,209,524.
Claims priority of provisional application 60/421293, filed on Oct. 25, 2002.
Prior Publication US 2007/0116144 A1, May 24, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. H04L 27/04 (2006.01)
U.S. Cl. 375—295  [375/260] 8 Claims
OG exemplary drawing
 
1. A system for transmitting a layered modulation signal characterized by a carrier to noise ratio (CNR) having an upper layer signal and a lower layer signal, wherein a power of the upper layer signal is separated from a power of the lower layer signal by a power separation S, the system defined by performing the steps of:
defining the system in terms of a set of system parameters, including an optimal power separation S between a power of a first modulation layer and a power of a second modulation layer and a required system carrier-to-noise ratio (CNRs);
determining an optimal power separation S to minimize an error rate of the lower layer signal (BERL); and
selecting remaining system parameters in the set of system parameters using the determined optimal power separation S, comprising the steps of:
determining a required CNR for the upper layer (CNRU) and a required CNR for the lower layer (CNRL) from a relationship between an upper layer coding rate (CUL) and CNRU, and a lower level coding rate (CLL) and CNRL; and
determining the required system CNR (CNRs) from CNRU, CNRL, and S.