Techniques for Radio Link Problem and Recovery Detection in a Wireless Communication System

Abstract

A technique for radio link detection in a wireless communication system includes estimating a first error rate of an indicator channel. In this case, the indicator channel includes an indication of a number of symbols in a control channel. A second error rate of the control channel is also estimated. The first and second error rates are then combined to provide a performance metric. Based on the performance metric, a determination is made as to whether a radio link problem exists.

1 - 20 . (canceled) 
     
     
         21 . A method, comprising:
 at a subscriber station,   estimating a first error rate for an indicator channel;   estimating a second error rate for a control channel;   comparing one of the first error rate and the second error rate to a first threshold to determine a radio link problem; and   comparing one of the first error rate and the second error rate to a second threshold to determine a radio link recovery.   
     
     
         22 . The method of  claim 21 , further comprising:
 combining the first and second error rates to generate a performance metric, wherein the comparing is based on the performance metric.   
     
     
         23 . The method of  claim 21 , further comprising:
 providing an indication when the comparing indicates a radio link problem.   
     
     
         24 . The method of  claim 21 , further comprising:
 providing an indication when the comparing indicates a radio link recovery.   
     
     
         25 . The method of  claim 21 , wherein the indicator channel occupies a first frequency band and estimating of the first error rate is based on a first reference signal occupying a first frequency adjacent to the first frequency band and a second reference signal occupying a second frequency adjacent to the first frequency band, wherein the first ad second frequencies are on opposite sides of the first frequency bands. 
     
     
         26 . The method of  claim 25 , wherein the first error rate is based on a first quality metric of the first reference signal and a second quality metric of the second reference signal. 
     
     
         27 . The method of  claim 26 , wherein the first error rate is based on interpolating the first quality metric and the second quality metric. 
     
     
         28 . The method of  claim 21 , wherein the indicator channel includes an indication of a number of symbols in the control channel. 
     
     
         29 . The method of  claim 23 , further comprising:
 determining when the radio link problem exists for a period of time;   indicating a radio link failure when the radio link problem exists for the period of time.   
     
     
         30 . The method of  claim 21 , wherein the method is performed for a plurality of indicator channels and a corresponding plurality of control channels and when a predetermined number of radio link problems exist, the method further comprises:
 powering down a transmitter of the subscriber station.   
     
     
         31 . A wireless communication device, comprising:
 a processor configured to:
 estimate a first error rate for an indicator channel; 
 estimate a second error rate for a control channel; 
 compare one of the first error rate and the second error rate to a first threshold to determine a radio link problem; and 
 compare one of the first error rate and the second error rate to a second threshold to determine a radio link recovery. 
   
     
     
         32 . The wireless communication device of  claim 31 , wherein the processor is further configured to:
 combine the first and second error rates to generate a performance metric, wherein the comparing is based on the performance metric.   
     
     
         33 . The wireless communication device of  claim 31 , wherein the processor is further configured to:
 provide an indication when the comparing indicates a radio link problem.   
     
     
         34 . The wireless communication device of  claim 31 , wherein the processor is further configured to:
 provide an indication when the comparing indicates a radio link recovery.   
     
     
         35 . The wireless communication device of  claim 31 , wherein the indicator channel occupies a first frequency band and the processor estimates the first error rate based on a first reference signal occupying a first frequency adjacent to the first frequency band and a second reference signal occupying a second frequency adjacent to the first frequency band, wherein the first and second frequencies are on opposite sides of the first frequency bands. 
     
     
         36 . The wireless communication device of  claim 35 , wherein the processor estimates the first error rate based on a first quality metric of the first reference signal and a second quality metric of the second reference signal. 
     
     
         37 . The wireless communication device of  claim 36 , wherein the processor estimates the first error rate by interpolating the first quality metric and the second quality metric. 
     
     
         38 . The wireless communication device of  claim 31 , wherein the indicator channel includes an indication of a number of symbols in the control channel. 
     
     
         39 . The wireless communication device of  claim 33 , wherein the processor is further configured to:
 determine when the radio link problem exists for a period of time;   indicate a radio link failure when the radio link problem exists for the period of time.   
     
     
         40 . The wireless communication device of  claim 31 , wherein the processor estimates and compares for a plurality of indicator channels and a corresponding plurality of control channels and when a predetermined number of radio link problems exist, the processor is further configured to:
 power down a transmitter of the wireless communication device.