Enhanced method for adaptive equalization technique in mobile wireless systems
AssigneeNational Semiconductor Corporation
InventorsAhmad Reza Bahai, Kumud Kumar Sanwal
Life of this patent
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Abstract
A method for adaptively equalizing an output of a digital communication channel, including steps of: generating an initial channel estimation; determining an initial set of metric states of a trellis, based on known symbols of a received input signal comprising a sequence of symbols; updating the set of metric states according to the initial channel estimation and the received signal; updating a set of paths for the metric states using a delayed tentative decision of a symbol of the received signal, to determine a set of survivor paths; and updating the channel estimation, based on the updated metrics, delayed tentative decision, and the received signal.
Claims26
A method for adaptively equalizing an output of a digital communication channel, comprising:
- generating an initial channel estimation;
- determining an initial set of metric states of a trellis, based on a training sequence of known symbols of a received input signal comprising a sequence of symbols;
- updating the set of metric states according to the initial channel estimation and the received signal;
- updating a set of paths for the metric states using a delayed tentative decision of a symbol of the received signal, to determine a set of survivor paths;
- and
- updating the channel estimation, based on the updated metrics, delayed tentative decision, and the received signal;
- and further comprising iterated training to determine the meteric states of the trellis, wherein in each iteration, the training sequence is reversed.
An adaptive equalizer device for an output of a digital communication channel, said device configured to:
- generate an initial channel estimation;
- determine an initial set of metric said of a trellis, based on a training sequence of known symbols of a received input signal comprising a sequence of symbols;
- update the set of metric states according to the initial channel estimation and the received signal;
- update a set of paths for the metric states using a delayed tentative decision of a symbol of the received signal, to determine a set of survivor paths;
- and
- update the channel estimation, based on the updated metrics, delayed tentative decision, and the received signal;
- and further configured to train iteratively to determine the metric states of the trellis, wherein in each iteration, the training sequence is reversed;
- determine an initial set of metric states of a trellis, based on a training sequence of known symbols of a received input signal comprising a sequence of symbols;
- update the set of metric states according to the initial channel estimation and the received signal;
- update a set of paths for the meteric states using a delay tentative decision of a symbol of the received signal, to determine a set of survivor paths;
- update the channel estimation, based on the updated metrics, delayed tentative decision, and the received signal;
- and
- to update said channel estimations for each of a set of surviving paths of the set of paths.
Dependencies are inferred from the claim text.