| 1. |
|
|
| 2. |
- Leblanc, James, et al.
(författare)
-
Fractionally-spaced constant modulus algorithm blind equalizer error surface characterization : effects of source distributions
- 1996
-
Ingår i: Conference Proceedings. - Piscataway, NJ : IEEE Communications Society. ; , s. 2944-2947
-
Konferensbidrag (refereegranskat)abstract
- The constant modulus algorithm (CMA) is a popular blind equalization algorithm. A common device used in demonstrating the convergence properties of CMA is the assumption that the source sequence is i.i.d. (independent, identically distributed). Previous results in the literature show that a finite length fractionally-spaced equalizer allows for perfect equalization of moving average channels (under certain channel conditions known as zero-forcing criteria). CMA has previously been shown to converge to such perfectly equalizing settings under an independent, platykurtic source. This paper investigates the effect of the distribution from which an independent source sequence is drawn on the CMA error surface and stationary points in the perfectly-equalizable fractionally-sampled equalizer case. Results include symbolic identification of all stationary points, as well as the eigenvalues and eigenvectors associated with their Hessian matrix. Results show quantitatively the loss of error surface curvature (in both direction and magnitude) at all stationary points. Simulations included demonstrate the affect this has on convergence speed.
|
|
| 3. |
- Leblanc, James, et al.
(författare)
-
Global CMA error surface characteristics, source statistic effects : polytopes and manifolds
- 1997
-
Ingår i: 1997 13th International Conference on Digital Signal Processing proceedings. - Piscataway, NJ : IEEE Communications Society.
-
Konferensbidrag (refereegranskat)abstract
- This work focuses on gaining insight to CMA behavior through identi cation of global properties of CMA stationary point locations due to source statistics (distributions and temporal correlation). The CMA error function under source correlation effects is viewed as a deformation of the iid CMA error surface. As deformations are the realm of topology, we look at some of the topological aspects connected with CMA source correlation. Some general characteristics of CMA under iid source are presented, noting relations to Morse Theory, polytopes, and Euler Characteristics.
|
|
| 4. |
|
|
| 5. |
- Leblanc, James P., et al.
(författare)
-
Fractionally spaced CMA equalizers under periodic and correlated inputs
- 1995
-
Ingår i: Conference proceedings ICASSP-95. - Piscataway, NJ : IEEE Communications Society. ; , s. 1041-1044
-
Konferensbidrag (refereegranskat)abstract
- CMA fractionally spaced equalizers (CMA-FSEs) have been shown, under certain conditions, to be globally asymptotically convergent to a setting which provides perfect equalization. Such a result relies heavily on the assumptions of a white source and no channel noise (as is the case in much of the literature's analysis of CMA). Herein, we relax the white source assumption and examine the effect of source correlation on CMA. Analytic results are meshed with examples showing CMA-FSE source correlation effects. Techniques for finding all stationary and saddle points on the CMA-FSE error surface are presented using recent developments in the algebraic-geometry community.
|
|
