Mobile station handover for base stations with adaptive antenna system

• US 20070123257A1
• Filed: 11/29/2005
• Published: 05/31/2007
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: Rateze Remote Mgmt. L.L.C. (Intellectual Ventures LLC)
• Original Assignee: AirNet Communications Corporation (Tecore Incorporated)
• Inventors: Nelson, Mark, Noll, John, Smith, Jeffrey, Schwaller, John
• Granted Patent: US 7,945,263 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/0064 of control information between different access points

Abstract

Method for transferring service for a mobile station call signal from a first base transceiver station to a second base transceiver station in a wireless mobile telecommunication system, while a call is in progress. The method can include receiving at a base transceiver station an access burst from a mobile station with a call already in progress and requiring service from the base transceiver station. Based on the received access burst, the base transceiver station can electronically steer a beam of an adaptive antenna array of the base transceiver station toward a location of the mobile station.

Claims

1. A method for transferring service for a mobile station call signal from a first base transceiver station to a second base transceiver station in a wireless mobile telecommunication system while a call is in progress, comprising:

receiving at a base transceiver station an access burst from a mobile station with a call already in progress and requiring service from said base transceiver station;

electronically steering a beam of an adaptive antenna array of said base transceiver station toward a location of said mobile station based on said access burst.

2. The method according to claim 1, further comprising automatically delaying a response to said access burst until a predetermined number of said access bursts have been received by said base transceiver station.

3. The method according to claim 2, further comprising generating at least one set of weighting parameters for said adaptive antenna array based on a plurality of said predetermined number of said access bursts.

4. The method according to claim 3, wherein said generating step further comprises determining said weighting parameters to produce an antenna pattern for said adaptive array exclusive of nulls intentionally positioned for avoiding interference with co-channel users.

5. The method according to claim 1, further comprising generating at least one set of weighting parameters for said adaptive antenna array based on said access burst to produce an antenna pattern for said adaptive array exclusive of nulls intentionally positioned for avoiding interference with co-channel users.

6. A base station transceiver station in a wireless mobile telecommunication system, comprising:

a receiver for receiving at said base transceiver station an access burst from a mobile station with a call already in progress and requiring service from said base transceiver station;

a receiver signal processor for detecting said access burst; and

an adaptive array antenna system that electronically steers a beam produced by said adaptive array antenna system toward a location of said mobile station based on said access burst.

7. The base transceiver station according to claim 6, wherein said receiver signal processor detects a predetermined number of said access bursts before said base transceiver station transmits a response to said access burst.

8. The base transceiver station according to claim 7, wherein said adaptive antenna array system generates at least one set of weighting parameters for said adaptive antenna array based on a plurality of said predetermined number of said access bursts.

9. The base transceiver station according to claim 8, wherein said adaptive antenna array determines said weighting parameters to produce an antenna pattern for said adaptive array exclusive of nulls intentionally positioned for avoiding interference with co-channel users.

10. The base transceiver station according to claim 6, wherein said adaptive array generates at least one set of weighting parameters to produce an antenna pattern for said adaptive array exclusive of nulls intentionally positioned for avoiding interference with co-channel users.

11. A method for transferring service for a mobile station call signal from a first base transceiver station to a second base transceiver station in a wireless mobile telecommunication system while a call is in progress, comprising:

monitoring with said second base transceiver station at least one transmission from said mobile station to said first base transceiver station;

electronically steering a beam of an adaptive antenna array of said base transceiver station toward a location of said mobile station based on said monitoring step.

12. The method according to claim 11, further comprising generating at least one set of weighting parameters for said adaptive antenna array based on said monitoring step.

13. The method according to claim 11, wherein said at least one transmission from said mobile station to said first base transceiver station is transmitted on a first frequency, and said generating step further comprises compensating for frequency differences between the first frequency and a second frequency that the second base station will use to communicate with said mobile station.

14. The method according to claim 11, further comprising analyzing with said second base transceiver station an access channel on which said mobile station can communicate with said second base transceiver station to access the services of said second base transceiver.

15. The method according to claim 14, further comprising identifying at least one co-channel station that is also using said access channel.

16. The method according to claim 15, further comprising generating at least one null with said adaptive antenna array concurrently with said electronically steering step, said null directed toward said at least one co-channel station.

17. The method according to claim 11, further comprising monitoring an access channel with said second base station and, in response to an access burst received from said mobile station, transmitting to said mobile station information for communicating with said second base station using said beam.

18. A wireless mobile telecommunication system, comprising:

a base transceiver station in a first cell of said wireless mobile communication system responsive to a handover request for monitoring at least one transmission of a call already in progress between a mobile station and an originating base transceiver station in a second cell of said wireless communication system;

an adaptive antenna system including an adaptive antenna array and an adaptive antenna processor configured for electronically steering a beam of said adaptive antenna array toward a location of said mobile station based on said monitoring step; and

a control processor responsive to at least one access request from said mobile station and causing said base transceiver station to transmit selected information to said mobile station using said beam.

19. The wireless mobile telecommunication system according to claim 18, wherein said selected information includes physical channel information.

20. The wireless mobile telecommunication system according to claim 18, wherein said adaptive antenna processor generates at least one set of weighting parameters for said adaptive antenna array based on said at least one transmission.

21. The wireless mobile telecommunication system according to claim 18, wherein said at least one transmission is transmitted on a traffic channel of said originating base transceiver station, and said adaptive antenna processor compensates for frequency differences between the traffic channel and an access channel that the base transceiver station will use to communicate with said mobile station.

22. The wireless mobile telecommunication system according to claim 18, wherein said adaptive antenna processor analyzes an access channel on which said mobile station can communicate with said base transceiver station to access the services of said second base transceiver, to identify at least one co-channel station that is using a frequency common to said access channel.

23. The wireless mobile telecommunication system according to claim 21, wherein said adaptive antenna system generates at least one null with said adaptive antenna array concurrently with said electronically steering step, said null directed toward said at least one co-channel station.

24. A method for transferring service for a mobile station call signal from a first base transceiver station to a second base transceiver station in a wireless mobile telecommunication system while a call is in progress, comprising:

receiving at a base transceiver station an access burst from a mobile station with a call already in progress and requiring service from said base transceiver station;

controlling an adaptive antenna array of said base transceiver station to generate a wide area antenna pattern when transmitting a response to said mobile station based on said access burst; and

after transmitting said response using said wide area antenna pattern, continuing communications with said mobile station on a traffic channel using adaptive array signal processing to produce a focused beam in a direction of said mobile station.

25. The method according to claim 24, further comprising continuing communications with said mobile station using adaptive array signal processing to produce a pattern of nulls for reducing co-channel interference with co-channel stations caused by transmissions from said base transceiver station to said mobile station.

26. The method according to claim 24, further comprising temporarily increasing the RF power level when transmitting said response from said BTS to said mobile station, to at least partially compensate for a decreased gain when using said wide area antenna pattern.

27. The method according to claim 24, wherein said response includes physical channel information useful to said mobile station for communicating with said base transceiver station on a traffic channel of said BTS.

28. A wireless telecommunication system comprising:

a base transceiver station in a first cell of said wireless telecommunication system, said base transceiver station responsive to a handover request for monitoring an access channel to detect an access request from a mobile station;

an adaptive antenna system including an adaptive antenna array and an adaptive antenna processor configured for electronically steering a beam of said adaptive antenna array toward a location of said mobile station; and

a control processor controlling said adaptive antenna array to temporarily generate a wide area antenna pattern when transmitting a response to said mobile station based on said access request

29. The wireless base transceiver system according to claim 28, wherein said control processor controls said adaptive antenna array after transmitting said response to continue communications with said mobile station on a traffic channel using adaptive array signal processing to produce a focused beam in a direction of said mobile station.

30. The wireless base transceiver station according to claim 29, wherein said control processor controls said adaptive antenna array after transmitting said response to continue communications with said mobile station on a traffic channel using adaptive array signal processing to produce a pattern of nulls for reducing co-channel interference with co-channel stations caused by transmissions from said base transceiver station to said mobile station.

31. The wireless base transceiver station according to claim 28, wherein said base transceiver station temporarily increases its transmitted RF power when transmitting said response from said base transceiver station to said mobile station.

32. The wireless base transceiver station according to claim 29, wherein said increase in transmitted RF power level at least partially compensates for a decreased gain when using said wide area antenna pattern.

33. The wireless base transceiver station according to claim 28, wherein said response includes physical channel information useful to said mobile station for communicating with said base transceiver station on a traffic channel of said BTS.