Method and system for improving uplink performance
View Patent ↗The present invention is directed to improvements for distributed antenna systems and more particularly to methods and systems for improving uplink communications. In one embodiment, Aggregation Point Noise Blocking provides for blocking or filtering 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. In another embodiment the signal can be regenerated to produce a signal that has a restored or very high SNR. An uplink regeneration block can be provided which demodulates the uplink signal to recover the transmitted information and then re-modulates the transmitted information to regenerate a signal at a restored or very high SNR.
1. A distributed antenna system comprising:
two or more uplink branches coupled to an aggregation point, each uplink branch connected to at least one antenna configured to receive uplink signals; and
the aggregation point comprising a selective noise blocking system 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 uplink branches from passing through the aggregation point.
2. A distributed antenna system according to claim 1 wherein the selective noise blocking system comprises
an analog to digital converter associated with each of the two or more uplink branches and adapted to convert each uplink signal transferred over each of the two or more uplink branches to a corresponding digital signal;
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. A distributed antenna system according to 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. A distributed antenna system according to 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. A distributed antenna system according to claim 2 further comprising a digital delay line between the activity identification block and the selective noise blocking component.
6. A distributed antenna system according to claim 2 wherein the selective noise blocking component is further adapted to attenuate signals not blocked.
7. A distributed antenna system according to 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 uplink branches from passing through the aggregation point.
8. A distributed antenna system according to 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. A distributed antenna system according to 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. A distributed antenna system according to claim 1 wherein the selective noise blocking component is further adapted to attenuate signals passed through the aggregation point.
11. A method of processing uplink signals in a digital antenna system having two or more uplink branches, the method comprising
receiving at least one uplink signal on at least one uplink branch;
detecting at an aggregation point uplink signal activity on one or more of the uplink branches; and
at the aggregation point, selectively combining uplink signals received from each uplink branch as a function of the uplink signal activity detected.
12. A method according to claim 11 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.
13. A method according to claim 12 further comprising selectively blocking the uplink signals as a function of an absence of signal activity detected.
14. A method according to claim 11 further comprising attenuating the signals selectively combined.
15. A method according to claim 11 further comprising
converting at least one of the uplink signals to a digital signal;
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;
combining digital signals that are not blocked to form a combined digital signal; and
converting the combined digital signal to an analog signal.
16. A method according to claim 11 further comprising
for at least one uplink branch, blocking signals corresponding to one or more frequencies from passing through to a combiner.
17. A method according to claim 11 further comprising
for at least one uplink branch, blocking signals corresponding to one or more time slots from passing through to a combiner.
18. A distributed antenna system comprising:
two or more uplink branches, each uplink branch coupled to an aggregation point at respective first ends of the uplink branch and connected to at least one antenna at respective second ends of the uplink branch;
the aggregation point comprising a selective noise blocking system 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 uplink branches from passing through the aggregation point.