Title :
A constrained LMS algorithm for interference rejection
Author :
Doherty, John F.
Author_Institution :
Dept. of Electr. & Comput. Eng., Iowa State Univ., Ames, IA, USA
Abstract :
A constrained least-mean-square (LMS) technique that utilizes a modified optimality criterion which enhances the detection capabilities of direct-sequence spread-spectrum systems is presented. Two transversal tapped delay lines (TDLs) are operated simultaneously, one containing the received data and the other containing the constraint data. One set of adaptive weights operates on both TDLs with the LMS algorithm as the update technique. The filter weights are updated with respect to both minimizing the mean-square output error and minimizing the constraint error. Two types of constraint conditions are considered. The first is a correlation-matching condition and the second is a minimum-filter-energy condition. Simulation results presented demonstrate the output mean-square error improvement obtained by using the constrained rejection filter
Keywords :
filtering and prediction theory; interference suppression; least squares approximations; signal processing; spread spectrum communication; constrained LMS algorithm; correlation-matching condition; direct-sequence spread-spectrum systems; filter weights; interference rejection; least-mean-square; minimum-filter-energy condition; modified optimality criterion; output mean-square error; transversal tapped delay lines; Delay lines; Equations; Error correction; Information filtering; Information filters; Interference constraints; Least squares approximation; Matched filters; Narrowband; Spread spectrum communication;
Conference_Titel :
Military Communications Conference, 1992. MILCOM '92, Conference Record. Communications - Fusing Command, Control and Intelligence., IEEE
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-0585-X
DOI :
10.1109/MILCOM.1992.244140
