Method and apparatus for mitigating distortion effects in the determination of signal usability

• US 5,469,465 A
• Filed: 11/02/1994
• Issued: 11/21/1995
• Est. Priority Date: 05/28/1993
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wilson, Timothy J., Birchler, Mark A., Jasper, Steven C.
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): Williams, Kimberly A.
• Application Number:
  US08/333,409
• Time in Patent Office: 384 Days
• Field of Search: 375/100, 375/101, 375/103, 375/99
• US Class Current: 375/346
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 17/20 of receivers
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

A receiver may reduce the effects of distortion when determining signal usability in the following manner. Upon receiving a signal, the receiver separates a desired component, an undesired component, and a distortion component, wherein the desired component includes the signal that was originally transmitted and the undesired component includes interference and noise. Having isolated the distortion component, it can be mitigated such that the usability of the signal received can be determined based on a ratio between the desired and undesired components.

Claims

1. In a receiver that receives a stream of information symbols, a method for mitigating distortion effects to enhance signal usability determination, the method comprises the steps of:

a) receiving a stream of information symbols to produce a symbol stream, wherein each information symbol of the symbol stream includes a desired component, an interference component, and a distortion component;

b) determining characteristics of the distortion component based on preestablished distortion information of the receiver and a transmitter that transmitted the symbol stream to produce distortion characteristics;

c) determining a representation of the desired component to produce a desired representation;

d) determining an undesired component based on the desired representation and the symbol stream;

e) determining at least one magnitude value based on the distortion characteristics;

f) when a magnitude of the undesired component is less than the at least one magnitude value, scaling the undesired component by a first predetermined value to produce a scaled undesired component;

g) when the magnitude of the undesired component is greater than the at least one magnitude value, scaling the undesired component by a second predetermined value to produce the scaled undesired component, wherein the second predetermined value is greater than the first predetermined value;

h) determining a representation of the interference component based on the scaled undesired component; and

i) determining an indicia of symbol stream usability based on the desired representation and the representation of the interference component.

2. In the method of claim 1, the determination of the undesired component of step (d) comprises subtracting the desired component from the symbol stream.

3. In the method of claim 2, the determination of the representation of the interference component of step (e) further comprises filtering the undesired component via a filter to attenuate the distortion component.

4. In the method of claim 1, the determination of the undesired component of step (d) comprises subtracting the desired component from the symbol stream.

5. In the method of claim 1, the determination of the representation of the interference component of step (e) further comprises filtering the undesired component via a filter to attenuate the distortion component.

6. An apparatus for mitigating distortion effects and enhancing signal usability determinations in a receiver, the apparatus comprises:

a signal receiver that receives a stream of information symbols to produce a symbol stream;

a distortion characteristics determiner, wherein the distortion characteristics determiner determines distortion characteristics for a distortion component of each information symbol of the symbol stream;

a desired component determiner, operably coupled to the signal receiver, wherein the desired component determiner determines a desired component for each information symbol of the symbol stream;

an undesired component determiner, operably coupled to the desired component determiner and the signal receiver, wherein the undesired component determiner determines an undesired component for each information symbol of the symbol stream based on the desired component and the symbol stream;

interference component determiner, operably coupled to the undesired component determiner and the distortion characteristics determiner, wherein the interference component determiner determines an interference component for each information symbol of the symbol stream based on the desired component, the distortion characteristics, and the undesired component;

a magnitude scaler, operably coupled to the interference component determiner, the distortion characteristics determiner, and the undesired component determiner, wherein the magnitude scaler scales a magnitude of the undesired component by a first predetermined value when the magnitude of the undesired component is less than at least one magnitude value and scales the magnitude of the undesired component by a second predetermined value when the magnitude of the undesired component is greater than the at least one magnitude value; and

a filter, operably coupled to the distortion characteristics determiner and the undesired component determiner, wherein the filter attenuates the distortion component from the undesired component.

7. An apparatus for mitigating distortion effects and enhancing signal usability determinations in a receiver, the apparatus comprises:

a signal receiver that receives a stream of information symbols to produce a symbol stream;

a distortion characteristics determiner, wherein the distortion characteristics determiner determines distortion characteristics for a distortion component of each information symbol of the symbol stream;

a desired component determiner, operably coupled to the signal receiver, wherein the desired component determiner determines a desired component for each information symbol of the symbol stream;

an undesired component determiner, operably coupled to the desired component determiner and the signal receiver, wherein the undesired component determiner determines an undesired component for each information symbol of the symbol stream based on the desired component and the symbol stream;

a selector, operably coupled to the undesired component determiner and the distortion characteristics determiner, wherein the selector selects selected undesired components of the undesired components based on the distortion component;

interference component determiner, operably coupled to the selector and the distortion characteristics determiner, wherein the interference component determiner determines an interference component for each information symbol of the symbol stream based on the desired component, the distortion characteristics, and the selected undesired component;

a magnitude scaler, operably coupled to the interference component determiner and the selector, wherein the magnitude scaler scales a magnitude of the selected undesired components by a first predetermined value when a magnitude of the interference component is less than at least one magnitude value and scales the magnitude of the selected undesired components by a second predetermined value when the magnitude of the interference component is greater than the at least one magnitude value; and

a filter, operably coupled to the distortion characteristics determiner and the undesired component determiner, wherein the filter attenuates the distortion component from the undesired component.