Method and apparatus for determining an operating condition in a communications system

Abstract

A communication system environment estimation apparatus and method. In one embodiment, an environment estimation apparatus according to the teachings of the present invention includes a plurality of antenna elements and a receiver coupled to receive uplink signals from the plurality of antenna elements. The apparatus also includes a signal processor coupled to receive the uplink signals to select an estimation of an environment responsive to the uplink signals received from the plurality of antenna elements.

1 . A method of characterizing an environment, comprising:
 receiving uplink signals from a plurality of antenna array elements;   calculating pairwise correlations of the uplink signals received by the plurality of antenna array elements;   calculating an average of absolute values of said pairwise correlations of the uplink signals received by the plurality of antenna array elements; and   selecting a high clutter environment estimation if the average of the absolute values of said pairwise correlations of the uplink signals received by the plurality of antenna array elements is less than a high clutter threshold.   
   
   
       2 . The method of  claim 1  wherein calculating said pairwise correlations of the uplink signals received by the plurality of antenna array elements comprises calculating a normalized dot product for said pairwise correlations of the uplink signals received by the plurality of antenna array elements. 
   
   
       3 . A method of characterizing an environment, comprising:
 receiving uplink signals from a plurality of antenna array elements;   calculating a correlation matrix from the uplink signals received by the plurality of antenna array elements;   estimating a source order from the correlation matrix; and   selecting a high interference environment estimation if the estimated source order is greater than a high interference threshold.   
   
   
       4 . The method of  claim 3  wherein estimating the source order in response to the correlation matrix comprises:
 calculating Eigen values of the correlation matrix; and   performing a sequential hypothesis technique on the Eigen values to estimate the source order.   
   
   
       5 . The method of  claim 3  wherein estimating the source order in response to the correlation matrix comprises:
 calculating Eigen values of the correlation matrix; and   performing an Akaike Information Criteria technique on the Eigen values to estimate the source order.   
   
   
       6 . The method of  claim 3  wherein estimating the source order in response to the correlation matrix comprises:
 calculating Eigen values of the correlation matrix; and   performing a minimum descriptive length technique on the Eigen values to estimate the source order.   
   
   
       7 . A method of characterizing an environment, comprising:
 receiving uplink signals from a plurality of antenna array elements;   calculating a signal to noise ratio in response to the uplink signals received from the plurality of antenna array elements;   measuring a bit error rate (BER) in response the uplink signals received from the plurality of antenna array elements;   determining an expected BER in response to the signal to noise ratio; and   selecting a high interference environment estimation if the measured BER is a BER threshold amount greater than the expected BER.   
   
   
       8 . The method of  claim 7  wherein calculating the signal to noise ratio in response to the uplink signals received from the plurality of antenna array elements comprises:
 measuring a received signal strength indication (RSSI) in response to the uplink signals received from the plurality of antenna array elements; and   measuring noise included in the uplink signals received from the plurality of antenna array elements.   
   
   
       9 . The method of  claim 8  further comprising selecting the high interference environment estimation if the measured BER is a BER threshold amount greater than the expected BER and the RSSI is greater than a RSSI threshold value.