US 5,136,593 A · Apparatus and method for fixed delay tree search

Abstract

A method for identifying a signal subject to intersymbol interference comprising the steps of receiving .tau.+1 samples of the signal where .tau. is greater than or equal to one; searching a tree representation of known values to determine the path of the branch of the tree which most closely corresponds to the .tau.+1 samples of the signal; and releasing the symbol of the first metric of the determined branch. The released symbol is the identity of the sample. Preferably, the receiving step includes the step of receiving .tau.+1 sequential samples, with each sample corresponding to a unique portion of the signal, and the searching step includes the step of comparing each symbol of each metric of each path of each branch with the symbol's corresponding sample in regard to time. An apparatus for identifying a signal subject to intersymbol interference comprising a device for implementing a fixed delay tree search on samples of the signal to determine a symbol associated with a given sample and then releasing that sample. The apparatus also is comprised of a device for inputting samples to the implementing a device.

Claims15

Dependent claims

A method for identifying signals subject to intersymbol interference comprising the step of:

receiving .tau.+1 samples of the signals where .tau..gtoreq.1;
and computer implemented steps of:
forming a tree representation of known responses such that a symbol of each metric of the tree is predetermined by the symbol's position in the tree representation of known responses and the symbol associated with each metric is identified from the sumbol's position, in the tree representation of known responses without the symbol having to be stored in memory, said symbol is representative of a predetermined value and is a digital signal;
searching the tree representation of known responses to determine a path of a branch of the tree which most closely corresponds to the .tau.+1 samples of the signals;
and
releasing the symbol of a first metric of a determined branch, said symbol being an identity of a first sample.

3 more elements

An apparatus for identifying a signal subject to intersymbol interference comprising:

means for implementing a fixed delay tree search on samples of the signal to determine a symbol associated with a given sample and then releasing that symbol;
means for inputting samples to the implementing means;
and
a feedback filter which receives the symbol released from the implementing means and produces a correction factor corresponding to a difference between a value of the released symbol and an actual value of a sample associated with the released symbol such that a value of a next in time sample more closely approximates a value of the symbol which identifies the next in time sample then the value of the sample associated with the released metric.

1 more element

Dependencies are inferred from the claim text.

Apparatus and method for fixed delay tree search

Life of this patent

Apparatus and method for fixed delay tree search

Life of this patent

Abstract

Claims15