Compensating for Doppler shifts resulting from relative velocities up to 10 m/s is far beyond the capability of conventional adaptive equalization structures, even with explicit phase tracking loops [1].
Different from existing methods employing joint equalization and symbolwise phase tracking technology, the proposed scheme decouples the interference cancelation (IC) operation and the phase compensation operation, leading to a generalized equalizer structure combining an IC equalizer with a phase compensator.
Two alternative low-complexity linear equalizer structures with MSE criterion are considered for subband-wise equalization: a complex FIR filter structure and a cascade of a linear-phase FIR filter and an allpass filter.
Two alternative linear low-complexity subcarrier equalizer structures are developed together with straightforward channel estimation-based methods to calculate the equalizer coefficients using pointwise equalization within each subband (in a frequency-sampled manner).
Figure 4 2LTC-4CPFsystemtem for and without equalization: (a) encoder structure, (b) decoder structure.
Regarding the implementation results of [29], we follow the estimation and equalization algorithms and structure precisely as described in the paper.
They determine the structure of equalization transfers named partial equalization, which deter secession from disadvantaged and advantaged regions.
The distinction of the two structures in terms of sampling rate reduction lies in the fact that the FS structure performs equalization in its internal behavior and therefore before sampling rate reduction while the PPN structure performs equalization after sampling rate reduction and consequently needs to use the single-tap equalizer to not increase the transceiver delay.
In this article, we furthermore propose a novel Equalization-based SA (ESA) structure, where the echo path is equalized by a linear filter to allow for an estimation of the loudspeaker nonlinearities by very small and efficient models.
In the fourth article, "Significance-aware filtering for nonlinear acoustic echo cancellation," by C. Hofmann, C. Huemmer, M. Guenther, and W. Kellermann, the authors propose a novel equalization-based significance-aware structure, where the echo path is equalized by a linear filter to allow for an estimation of the loudspeaker nonlinearities by very small and efficient models.
