System and method for anticipatory receiver switching based on signal quality estimation

Abstract

In various embodiments, a first and second complex multiplier may be configured to receive an input signal and provide a baseband I component signal and a baseband Q component signal, respectively. A first and second filter may be configured to filter the baseband I component signal and the baseband Q component signal, respectively. An equalizer may be configured to equalize the filtered baseband I component signal and the filtered baseband Q component signal. A carrier recovery portion may be configured to generate a reference signal based on the equalized filtered baseband I component signal and the equalized filtered baseband Q component signal. A first and second multilevel comparator may be configured to receive the equalized filtered baseband I component signal from the carrier recovery portion and provide an output I and receive the equalized filtered baseband Q component signal and provide an output Q signal for further modulation.

1 - 12 . (canceled) 
     
     
         13 . A system, comprising:
 a first estimating circuit for estimating a first signal quality metric of a first signal, the first signal quality metric being based on a distance signal that is a function of a distance between a real symbol location of a real symbol of the first signal and an associated predetermined ideal symbol location of an ideal symbol;   a comparing circuit for comparing the first signal quality metric to a predetermined threshold to determine whether the first signal quality metric meets a signal quality, and for providing an alarm indicator when the first signal quality metric does not meet the signal quality;   a flag circuit for determining whether the alarm indicator from the comparing circuit satisfies an alarm condition; and   a switching circuit for switching from the first signal to a second signal in response to satisfaction of the alarm condition, the second signal being substantially independent of the first signal.   
     
     
         14 . The system of  claim 13 , wherein the first and second signals are baseband signals. 
     
     
         15 . The system of  claim 13 , wherein the switching circuit is configured to switch from the first signal to the second signal based on one or more of: intermediate frequency (IF) spectrum information, IF slope information, bit-error-rate (BER) information, signal degradation information, and signal outage information. 
     
     
         16 . The system of  claim 15 , wherein the signal degradation information is provided by a forward-error-coding (FEC) process. 
     
     
         17 . The system of  claim 13 , wherein the switching circuit is configured to switch from the first signal to the second signal according to a switching request priority associated with the comparison of the first signal quality metric to the predetermined threshold and other signal quality information. 
     
     
         18 . The system of  claim 17 , wherein the switching request priority comprises bit-error-rate (BER), frame loss, signal degradation, intermediate frequency (IF) slope, or low receiver signal level (RSL) sensed at a radio antenna port. 
     
     
         19 . The system of  claim 13 , wherein the switching circuit comprises a differential absolute delay equalizer (DADE) circuit configured to compensate for delay between the first signal and the second signal. 
     
     
         20 . The system of  claim 19 , wherein the DADE circuit is configured to dynamically correct the delay if a first receiver associated with the first signal experiences multipath fading. 
     
     
         21 . The system of  claim 13 , wherein the flag circuit is configured to determine whether the alarm indicator satisfies the alarm condition continuously, or at a predetermined interval. 
     
     
         22 . A method, comprising:
 estimating a first signal quality metric of a first signal, the first signal quality metric being based on a distance signal that is a function of a distance between a real symbol location of a real symbol of the first signal and an associated predetermined ideal symbol location of an ideal symbol;   comparing the first signal quality metric to a predetermined threshold to determine whether the first signal quality metric meets a signal quality;   providing an alarm indicator when the first signal quality metric does not meet the signal quality;   determining whether the alarm indicator satisfies an alarm condition; and   switching from the first signal to a second signal in response to satisfaction of the alarm condition, the second signal being substantially independent of the first signal.   
     
     
         23 . The method of  claim 22 , wherein the first and second signals are baseband signals. 
     
     
         24 . The method of  claim 22 , wherein the switching from the first signal to the second signal comprises switching from the first signal to the second signal based on one or more of:
 intermediate frequency (IF) spectrum information, IF slope information, bit-error-rate (BER) information, signal degradation information, and signal outage information.   
     
     
         25 . The method of  claim 24 , wherein the signal degradation information is provided by a forward-error-coding (FEC) process. 
     
     
         26 . The method of  claim 22 , wherein the switching from the first signal to the second signal comprises switching from the first signal to the second signal according to a switching request priority associated with the comparison of the first signal quality metric to the predetermined threshold and other signal quality information. 
     
     
         27 . The method of  claim 26 , wherein the switching request priority comprises bit-error-rate (BER), frame loss, signal degradation, intermediate frequency (IF) slope, or low receiver signal level (RSL) sensed at a radio antenna port. 
     
     
         28 . The method of  claim 22 , wherein the switching from the first signal to the second signal comprises compensating for delay between the first signal and the second signal. 
     
     
         29 . The method of  claim 28 , wherein the compensating for delay between the first signal and the second signal comprises dynamically correcting the delay if a first receiver associated with the first signal experiences multipath fading. 
     
     
         30 . The method of  claim 22 , wherein the determining whether the alarm indicator satisfies the alarm condition comprises determining whether the alarm indicator satisfies the alarm condition continuously, or at a predetermined interval. 
     
     
         31 . A system, comprising:
 means for estimating a first signal quality metric of a first signal, the first signal quality metric being based on a distance signal that is a function of a distance between a real symbol location of a real symbol of the first signal and an associated predetermined ideal symbol location of an ideal symbol;   means for comparing the first signal quality metric to a predetermined threshold to determine whether the first signal quality metric meets a signal quality;   means for providing an alarm indicator when the first signal quality metric does not meet the signal quality;   means for determining whether the alarm indicator satisfies an alarm condition; and   means for switching from the first signal to a second signal in response to satisfaction of the alarm condition, the second signal being substantially independent of the first signal.