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

• US 5,406,588 A
• Filed: 05/28/1993
• Issued: 04/11/1995
• 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:
  US08/069,947
• Time in Patent Office: 683 Days
• Field of Search: 375/99, 375/100, 375/101, 375/103
• 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 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 a representation of the interference component based on the undesired component and the distortion characteristics; and

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

wherein step (e) further comprises;

e1) determining at least one magnitude value based on the distortion characteristics;

e2) when magnitude of the undesired component is less than the at least one magnitude value, scaling the undesired component by a first predetermined value; and

e3) 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, wherein the second predetermined value is greater than the first predetermined value.

2. In a receiver that receives a stream of information symbols, wherein each information symbol of the stream of information symbols includes a desired information symbol component, an interference component, and a distortion component, a method for substantially eliminating the distortion component, the method comprises the steps of:

a) receiving the stream of information symbols to produce a symbol stream;

b) determining, by the receiver, representations for each of the desired information symbol components to produce symbol representations;

c) determining, by the receiver, distortion characteristics based on preestablished distortion information of the receiver and a transmitter that transmitted the symbol stream;

d) determining, by the receiver, undesired components based on the symbol representations and the symbol stream;

e) determining, by the receiver, selected undesired components of the undesired components based on the distortion characteristics;

f) filtering, by the receiver, the distortion components from the selected undesired components via a filter to produce filtered selected undesired components; and

g) determining, by the receiver, a representation of the interference components based on the filtered selected undesired components and the desired components such that the representation of the interference components and the desired components form a basis for determining an indicia of usability of the symbol stream.

3. In the method of claim 2, the determination of the representation of the interference components of step (g) further comprises:

g1) determining at least one magnitude value based on the distortion characteristics;

g2) when magnitude of a filtered selected undesired component of the filtered selected undesired components is less than the at least one magnitude value, scaling the filtered selected undesired component by a first predetermined value; and

g3) when the magnitude of a filtered selected undesired component of the filtered selected undesired components is greater than the at least one magnitude value, scaling the filtered selected undesired component by a second predetermined value, wherein the second predetermined value is greater than the first predetermined value.

4. In the method of claim 2, the determination of the undesired components of step (d) comprises subtracting the symbol representations from the symbol stream.

5. 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; and

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;

wherein the apparatus further comprises a magnitude scaler that is operably coupled to the interference component determiner, the distortion characteristics determiner, and the undesired component determiner, wherein the magnitude scaler scales 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.

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;

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,

wherein the apparatus further comprises a magnitude scaler that is operably coupled to the interference component determiner and the selector, wherein the magnitude scaler scales magnitude of the selected undesired components by a first predetermined value when the 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.