Method and system for improving uplink performance

Abstract

Distributed antenna systems and more particularly to methods and systems for improving uplink communications are disclosed. In one embodiment, Aggregation Point Noise Blocking provides for blocking or filtering of the noise contributed by one or more of the branches coupled to an aggregation point that are not carrying the signal from a particular terminal. Signal activity from a given terminal on a particular branch can be identified and that information can be used to selectively block or filter the signal noise contributed by the other branches to an aggregation point. The selective blocking or filtering can also include an attenuation function to attenuate the signal and provide dynamic range smoothing.

1 . A distributed antenna system comprising:
 a signal source configured to send and receive one or more signals;   two or more uplink branches coupled to an aggregation point, each uplink branch comprising an antenna;   the aggregation point comprising a selective noise blocking system configured to detect uplink signal activity received by one or more of the uplink branches and to selectively block uplink signals from one or more of the uplink branches from passing through the aggregation point;   the selective noise blocking system comprising an analog to digital converter associated with each of the two or more uplink branches and configured to convert each uplink signal transferred over each of the two or more uplink branches to a corresponding digital signal.   
     
     
         2 . The distributed antenna system of  claim 1  further comprising:
 an activity identification block associated with each of the two or more uplink branches and adapted to detect uplink signal activity in the corresponding digital signal; 
 a selective noise blocking component associated with each of the two or more uplink branches and adapted to selectively block the corresponding digital signals as a function of the uplink signal activity detected; 
 a digital combiner coupled to each selective noise blocking component and adapted to receive and combine the digital signals passed by each selective noise blocking component; and 
 a digital to analog converter coupled to the digital combiner adapted to convert the combined signal to an analog signal. 
 
     
     
         3 . The distributed antenna system of  claim 2  wherein the activity identification block communicates information concerning the uplink signal activity detected to a controller and the controller controls the selective noise blocking component to selectively block the digital signals received from one of the uplink branches. 
     
     
         4 . The distributed antenna system of  claim 3  wherein the controller produces an activity map indicating the uplink branches over which uplink signal activity was detected and the activity map is used to control the selective noise blocking component to selectively block or selectively pass digital signals received from one or more of the uplink branches. 
     
     
         5 . The distributed antenna system of  claim 2  further comprising a digital delay line between the activity identification block and the selective noise blocking component. 
     
     
         6 . The distributed antenna system of  claim 2  further comprising wherein the selective noise blocking component is further adapted to attenuate signals not blocked. 
     
     
         7 . The distributed antenna system of  claim 1  wherein the selective noise blocking system includes a digital signal processor adapted to detect uplink signal activity received by one or more of the uplink branches and to selectively block uplink signals from one or more of the uplink branches from passing through the aggregation point. 
     
     
         8 . The distributed antenna system of  claim 1  wherein each terminal is assigned a unique frequency for communicating over an uplink branch and the selective noise blocking signal is adapted to selectively block uplink signals by filtering signals having one or more frequencies over which no activity was detected. 
     
     
         9 . The distributed antenna system of  claim 1  wherein each terminal is assigned a time-slot for communicating over an uplink branch and the selective noise blocking signal is adapted to selectively block uplink signals by blocking signals during one or more time-slots during which no activity was detected. 
     
     
         10 . The distributed antenna system of  claim 1  wherein the selective noise blocking component is further adapted to attenuate signals passed through the aggregation point. 
     
     
         11 . The distributed antenna system of  claim 2  wherein each antenna is capable of wirelessly transmitting signals to a terminal and capable of receiving wireless signals from a terminal. 
     
     
         12 . A method of processing uplink signals in a digital antenna system having two or more uplink branches each uplink branch comprising an antenna, the method comprising:
 receiving at least one analog uplink signal on at least one uplink branch;   converting the at least one analog uplink signal to a digital signal;   detecting uplink signal activity on one or more of the uplink branches; and   selectively combining digital uplink signals received from each uplink branch as a function of the uplink signal activity detected.   
     
     
         13 . The method of  claim 12  further comprising, for at least one uplink branch, selectively blocking or passing the uplink signals to a combiner as a function of the uplink signal activity detected. 
     
     
         14 . The method of  claim 13  further comprising selectively blocking the uplink signals as a function of an absence of signal activity detected. 
     
     
         15 . The method of  claim 12  further comprising attenuating the signals selectively combined. 
     
     
         16 . The method of  claim 12  further comprising:
 detecting signal activity in the digital signal; 
 selectively blocking the passage of the digital signal as a function of the signal activity detected in the digital signal; and 
 combining digital signals that are not blocked to form a combined digital signal. 
 
     
     
         17 . The method of  claim 16  further comprising converting the combined digital signal to an analog signal. 
     
     
         18 . The method of  claim 16  further comprising filtering the digital signal with a digital signal processor (DSP). 
     
     
         19 . The method of  claim 16  further comprising delaying the digital signal with a digital delay line. 
     
     
         20 . The method of  claim 12  further comprising for at least one uplink branch, blocking signals corresponding to one or more frequencies from passing through to a combiner. 
     
     
         21 . The method of  claim 12  further comprising for at least one uplink branch, blocking signals corresponding to one or more time-slots from passing through to a combiner. 
     
     
         22 . The method of  claim 16  wherein each antenna is capable of wirelessly transmitting signals to a terminal and capable of receiving wireless signals from a terminal.