Method and apparatus for equalization control
AssigneeQUALCOMM Incorporated
InventorsByoung-Hoon Kim, Durga Malladi, Yongbin Wei
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Abstract
An equalization filter is provided with the ability to softly switch between pure linear equalization and decision feedback equalization. A reliability gain factor and an associated gain factor calculated by a predetermined mapping relation are provided in a decision feedback path and a feedforward path, respectively. Increasing the reliability gain factor increases the significance of the decision feedback filtering. Better performance than pure linear equalization and pure decision feedback equalization can be achieved.
Claims35
A device configured to process a signal comprising symbol sequences transmitted over a channel, said device comprising:
- a first filtering circuit having an input receiving said signal;
- and
- a feedback loop comprising a subtractor, a decision unit, and a second filter, wherein said subtractor is connected to subtract the output of said second filter from the output of said first filter, wherein said decision unit has an input connected to the output of said subtractor and an output connected to the input of said second filter, and wherein said second filter has coefficients weighted by a scalar value comprising a measure of decision reliability.
A device configured to process a signal comprising symbol sequences transmitted over a channel, said device comprising:
- a first filter having an input receiving said signal;
- a delay unit having its input coupled to the output of said first filter;
- a second filter having its input coupled to the output of said delay unit;
- an adder connected to sum the output of said first filter and the output of said second filter;
- and
- a decision feedback loop comprising a subtractor, a decision unit, and a third filter having substantially the same filter coefficients as said second filter, wherein said subtractor is connected to subtract the output of said third filter from the output of said adder and said decision unit has an input connected to the output of said subtractor and an output connected to the input of said third filter.
A method of processing a received signal, said method comprising soft-switching between linear equalization and decision feedback equalization.
A method of processing a received signal, said method comprising:
- receiving a signal;
- filtering said signal with a first filter;
- filtering the output of said first filter with a second filter;
- adding the output of said first filter to the output of the second filter;
- subtracting a decision feedback signal from the result of said step of adding to provide a signal for decision;
- constructing an estimate of the result symbol of said step of subtracting such that the estimate is one of a set of predetermined symbols;
- and
- filtering a sequence of said symbol estimates to provide said decision feedback signal with a third filter having substantially the same filter coefficients as said second filter.
A device for processing a received signal, said device comprising:
- means for receiving said signal;
- and
- means for soft-switching between linear equalization and decision feedback equalization.
A device configured to process a received signal, the device comprising:
- means for filtering said signal with a first filter;
- means for filtering the output of said first filter with a second filter;
- means for adding the output of said first filter to the output of the second filter;
- means for subtracting a decision feedback signal from the result of adding to provide a signal for constructing;
- means for constructing an estimate of the result of subtracting such that the estimate is one of a set of predetermined symbols;
- and
- means for filtering a sequence of said symbol estimates to provide said decision feedback signal with a third filter having substantially the same filter coefficients as said second filter.
Dependencies are inferred from the claim text.