Adaptive Equalization for Wireless Channels - Adaptive Signal Processing in Wireless Communications - page 245

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

5 10 15 20 25 30

Sorted tap number

FIgure 9.4 The tap magnitudes of an optimal equalizer, sorted in descending order. Note that
although there are no zero values, the equalizer is still somewhat sparse, since two-thirds of the
values are below 10% of the peak value.

10 0

NLMS

MPNLMS

PNLMS

10 −1

IPNLMS

10 −2

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Symbol number

FIgure 9.5 A demonstration of the convergence improvement of adaptive equalization of
wireless channels due to the use of proportionate adaptation. The algorithms considered are all
in the normalized LMS family: NLMS [29], PNLMS [18], MPNLMS [39], and IPNLMS [42]. The
optimal equalizer tap magnitudes are shown in Figure 9.4.