Method for optimally adjusting a decision level of a receiver and device thereof

• US 20110164874A1
• Filed: 07/22/2009
• Published: 07/07/2011
• Est. Priority Date: 09/11/2008
• Status: Abandoned Application

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Zhang, Qi
• Application Number:
  US13/062,947
• Publication Number:
  US 20110164874A1
• Time in Patent Office: Days
• US Class Current: 398/38
• CPC Class Codes: H04B 10/695 Arrangements for optimizing the decision element in the receiver, e.g. by using automatic threshold control

Abstract

The present invention discloses a method and a device for optimally adjusting the decision level of a receiver, wherein the method includes: monitoring optical power received by an optical receiver; determining whether the variation amplitude of the optical power is greater than a predefined value; if yes, then updating a current initial value of the decision level according to the optical power; obtaining an error signal of a transmitted signal from the output end of the optical receiver; determining whether the decision level needs adjusting according to the error signal; if yes, then further analyzing the error signal according to the current initial value to obtain the result of the analysis; otherwise, exiting the execution program directly; and adjusting the decision level from the current initial value according to the result of the analysis. By monitoring the received optical power and setting the initial value of the decision level according to the received optical power, the method and the device avoid the interruption in the system service caused by a long search for the initial value of the decision level due to the variation of the optical power and thus greatly improve the stability of the system.

Claims

1. A method for optimally adjusting a decision level of a receiver, including:

monitoring optical power received by an optical receiver;

determining whether the variation amplitude of the optical power is greater than a predefined value;

if yes, then updating a current initial value of the decision level according to the optical power;

obtaining an error signal of a transmitted signal from the output end of the optical receiver;

determining whether the decision level needs adjusting according to the error signal;

if yes, then further analyzing the error signal according to the current initial value to obtain the result of the analysis;

otherwise, exiting the execution program directly; and

adjusting the decision level from the current initial value according to the result of the analysis.

2. The method according to claim 1, before the step of monitoring the optical power received by an optical receiver, further including:

monitoring states of loss of signal (LOS) and loss of frame (LOF); and

determining whether the LOS or LOF occurs;

if yes, then exiting the execution program.

3. The method according to claim 1, after the step of adjusting the decision level from the current initial value, further including:

re-obtaining an error signal of a transmitted signal from the output end of the optical receiver.

4. The method according to claim 1, wherein the step of obtaining the result of the analysis includes:

determining an adjustment direction of the decision level; and

determining an adjustment step size of the decision level.

5. The method according to claim 4, wherein the step of determining the adjustment step size of the decision level includes:

calculating the adjustment step size of the decision level according to the error signal, obtaining a large adjustment step size when the error signal is strong, and obtaining a small adjustment step size when the error signal is weak.

6. The method according to claim 4, wherein the step of determining the adjustment step size of the decision level includes:

reading the value of the adjustment step size of the decision level from pre-stored adjustment step size data.

7. A device for optimally adjusting a decision level of a receiver, including:

a received power monitoring module for monitoring optical power received by an optical receiver;

an initial value setting module which is connected with the received power monitoring module to compare the optical power with a predefined value and re-adjust and re-set a current initial value of the decision level according to the result of the comparison;

an error signal obtaining module which is connected with the output end of the optical receiver to obtain an error signal of a transmitted signal from the optical receiver;

an error signal analyzing module which is connected with the error signal obtaining module to determine whether the decision level needs adjusting according to the error signal and analyze the error signal to obtain a result of the analysis; and

a decision level adjusting module which is connected with the error signal analyzing module to adjust the decision level of the optical receiver from the current initial value according to the result of the analysis.

8. The device according to claim 7, wherein the initial value setting module sets the current initial value through a coefficient modification or reads the current initial value from a pre-stored data table;

wherein the data of the pre-stored data table are obtained from experiments and are the optimal initial values of the decision level at different optical power.

9. The device according to claim 7, wherein the analysis result obtained by the error signal analyzing module includes:

determining an adjustment direction and an adjustment step size of the decision level.

10. The device according to claim 9, wherein the adjustment step size of the decision level is obtained from a calculation according to the error signal or from pre-stored adjustment step size data.