Smart antenna for interference rejection with enhanced tracking

1. A smart antenna system for communicating wireless signals between a mobile device and a plurality of fixed base stations using one or more channels and one or more beams, said smart antenna system comprising

a control subsystem, a radio transceiver and an antenna subsystem coupled to each other to

perform scanning of one or more combinations of base stations, channels and beams using one or more test links established with one or more of said fixed base stations, said one or more test links using at least some of the channels and the beams;

select a first combination of base station, channel and beam based on data obtained during scanning;

establish a first operating link for transmitting a wireless signal to the currently selected base station using the currently selected channel and beam; and

after establishing said first operating link, perform continued scanning using one or more test links established with one of

the currently selected base station and channel, and one or more beams different from the currently selected beam, and

one or more combinations of base stations, channels and beams,

said continued scanning being performed aperiodically, and the interval between consecutive continued scanning operations is pseudo-random,

wherein before performing said continued scanning, said control subsystem inserts a downtime, and said continued scanning is performed during said downtime.

2. The system of claim 1 , wherein if based on data obtained during said continued scanning, a second combination of base station, channel and beam is found to perform better than the selected first combination, then said control subsystem

selects the second combination of base station, channel and beam; and

establishes a second operating link for transmitting a wireless signal to the selected base station from said second combination, using the selected channel and beam from said second combination.

3. The system of claim 1 , wherein one or more combinations of base stations, channels and beams are used in said continued scanning every downtime.

4. The system of claim 3 , wherein said control subsystem calculates the duration of the downtime before inserting said downtime.

5. The system of claim 4 , wherein said calculated duration of downtime is less than a threshold duration to obtain sufficient data to determine performance of one combination; and said continued scanning is performed over more than one downtime until sufficient data is obtained.

6. The system of claim 4 , wherein a plurality of combinations are used in said continued scanning, and said calculated duration of downtime is less than a threshold duration to obtain sufficient data to determine performance of all combinations within said plurality of combinations; and said continued scanning is performed over more than one downtime until sufficient data is obtained.

7. The system of claim 2 , wherein the finding of better performance of the said second combination of base station, channel and beam than the selected first combination is based on a score calculated using at least one of signal-to-noise ratio (SNR), signal-to-interference-and-noise-ratio (SINR), base station load, packet error rate (PER) and throughput.

8. A method of communicating wireless signals between a mobile device and a plurality of fixed base stations using one or more channels and having one or more beams, said method comprising

scanning one or more combinations of base stations, channels and beams using one or more test links established with one or more of said fixed base stations, said one or more test links using at least some of the one or more channels and the one or more beams;

selecting a first combination of base station, channel and beam based on data obtained during the scanning;

establishing a first operating link for transmitting a wireless signal to the selected base station using the selected channel and beam; and

after establishing said first operating link, performing continued scanning using one or more test links established with one of

the currently selected base station and channel, and using one or more beams different from the currently selected beam, and

one or more combinations of base stations, channels and beams,

wherein said continued scanning is performed aperiodically, and

the interval between consecutive continued scanning operations is pseudo-random,

wherein prior to performing continued scanning,

inserting a downtime, and

said continued scanning is performed during said downtime.

9. The method of claim 8 , wherein if based on data obtained during said continued scanning, a second combination of base station, channel and beam is found to perform better than the selected first combination, then

selecting the second combination of base station, channel and beam; and

establishing a second operating link for transmitting a wireless signal to the selected base station from said second combination, using the selected channel and beam from said second combination.

10. The method of claim 8 , wherein one or more combinations of base stations, channels and beams are used in said continued scanning every downtime.

11. The method of claim 10 , further comprising calculating the duration of the tracking downtime before inserting said downtime.

12. The method of claim 11 , wherein said calculated duration of downtime is less than a threshold duration to obtain sufficient data to determine performance of one combination, and

said continued scanning is performed over more than one downtime until sufficient data is obtained.

13. The method of claim 11 , wherein a plurality of combinations are used in said continued scanning,

said calculated duration of downtime is less than a threshold duration to obtain sufficient data to determine performance of all combinations within said plurality of combinations; and

said continued scanning is performed over more than one downtime until sufficient data is obtained.

14. The method of claim 9 , wherein the finding of better performance of the said second combination of base station, channel and beam than the selected first combination is based on a score calculated using at least one of signal-to-noise ratio (SNR), signal-to-interference-and-noise-ratio (SINR), base station load, packet error rate (PER) and throughput.