| Paper: | SPCOM-P12.2 | ||
| Session: | Detection, Estimation, and Demodulation | ||
| Time: | Friday, May 21, 13:00 - 15:00 | ||
| Presentation: | Poster | ||
| Topic: | Signal Processing for Communications: Detection, Estimation, and Demodulation | ||
| Title: | PRECONDITIONED CONJUGATE GRADIENT BASED FAST COMPUTATION OF INDIRECT DECISION FEEDBACK EQUALIZER | ||
| Authors: | Peilu Ding; Purdue University | ||
| Michael Zoltowski; Purdue University | |||
| Mark Fimoff; Zenith Electronics Corporation | |||
| Abstract: | In this paper, we use the Preconditioned Conjugate Gradient (PCG) method to rapidly compute the tap weights of a minimum mean-square error (MMSE) decision feedback equalizer (DFE). The equalizer setting is computed indirectly after channel estimation. According to the Toeplitz block structure of the MMSE DFE equation $\bf{Rw=r}$, the preconditioner $\bf P$ is chosen to be a block diagonal matrix with circulant blocks along its diagonal. The spectral clustering property of the preconditioner matrix is analyzed. It is shown that the eigenvalues of ${\bf P}^{-1}{\bf R}$ are clustered around unity except for a small number of outliers when the number of the equalizer taps becomes large. The preconditioner can be inverted via Fast Fourier Transform (FFT) with complexity O(N\log N)$. Since the PCG method converges in a small number of steps, the total complexity for computing the DFE setting is proportional to $O(N\log N)$. The proposed scheme is also suitable for ''smart'' initialization which can further reduce thecomputational burden by decreasing the number of iteration teps.Simulations of a DFE for Digital TV channels demonstrates superior performance of the scheme. | ||
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