Title :
The transversal and lattice multiple modulus algorithms for blind equalization of QAM signals
Author :
Axford, R.A., Jr. ; Milstein, L.B. ; Zeidler, J.R.
Author_Institution :
Naval Command, Control & Ocean Surveillance Center, San Diego, CA, USA
Abstract :
The most popular algorithm for blind equalization of QAM signals is the constant modulus algorithm (CMA). However, because the CMA cost function is not matched to constellations with signal points on multiple radii, CMA can exhibit excessive misadjustment for QAM signals. This paper develops an alternative to CMA, the multiple modulus algorithm (MMA), which is based on stochastic gradient minimization of a cost function that goes to zero at each radius of the QAM constellation. For the applicable QAM constellations, MMA exhibits significantly reduced misadjustment compared to CMA. A lattice implementation of MMA is also presented
Keywords :
adaptive equalisers; adaptive signal processing; minimisation; quadrature amplitude modulation; stochastic processes; CMA cost function; QAM signals; blind equalization; constant modulus algorithm; constellations; excessive misadjustment; lattice implementation; lattice multiple modulus algorithms; multiple modulus algorithm; stochastic gradient minimization; transversal multiple modulus algorithms; Blind equalizers; Constellation diagram; Cost function; Lattices; Minimization methods; Oceans; Phase shift keying; Quadrature amplitude modulation; Stochastic processes; Surveillance;
Conference_Titel :
Military Communications Conference, 1995. MILCOM '95, Conference Record, IEEE
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-2489-7
DOI :
10.1109/MILCOM.1995.483534
