Multi-mode frequency domain equalization with adaptation to varying channel conditions

摘要

Methods and systems to configure a receiver based on a channel condition. A system may be implemented to estimate a channel based on PN sequences in a received signal, concurrently equalize a frequency domain representation of the signal with multiple blind adaptive equalizers, and evaluate results of the equalizations to select coefficients of one of the equalizers for further processing. A first equalizer may implement a constant-step-size (CSS) algorithm for a static channel. A second equalizer may implement a variable-step-size (VSS) algorithm for a dynamic channel. Static and dynamic channels may be distinguished based on convergence/divergence of the equalizers, which may be determined from a mean square error estimated from PN sequences in results of the blind equalizations. Subsequent processing may include linear and/or directed-decision equalization, channel estimation, and turbo equalization, which may be performed in the frequency domain, and which may be configurable based on the channel condition.

主权项

1. An apparatus to receive a signal over a channel, comprising:
a first channel estimator to estimate the channel based on PN sequences of the signal; first and second adaptive blind equalizers to concurrently equalize a frequency domain representation of the received signal; a selector to select weights of one of the first and second adaptive blind equalizers based on a condition of the channel; a linear adaptive equalizer to equalize the frequency domain representation of the received signal, including to apply the selected weights as initial linear adaptive equalizer weights and to adapt the initial linear adaptive equalizer weights based on equalization results of the linear adaptive equalizer; and a decision system to generate decisions regarding the symbols based in part on the equalization results of the linear adaptive equalizer.