SYSTEM AND METHOD FOR COMMUNICATING WITH AIRCRAFT THROUGH CELLULAR BASE STATION TOWERS

• US 20060264242A1
• Filed: 05/12/2006
• Published: 11/23/2006
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Dent, Paul Wilkinson
• Granted Patent: US 7,801,521 B2
• Time in Patent Office: Days
• US Class Current: 455/562.100
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service

Abstract

An antenna arrangement, method, and cellular communications system for transmitting and receiving signals between a base station tower, ground-based mobile subscribers, and an aircraft. The antenna arrangement includes a vertically oriented array of antenna elements, and a feedline arrangement that feeds the antenna elements with progressively phase-retarded signals, thereby generating an elevated antenna beam directed upward toward the aircraft and away from the ground-based mobile subscribers. In one embodiment, the antenna arrangement also generates a horizontal antenna beam for communicating with the ground-based subscribers. The horizontal beam and the elevated beam are sufficiently separated in elevation to prevent mutual interference when using the same frequency spectrum.

Claims

1. An antenna arrangement in a cellular base station for transmitting and receiving signals between the base station and ground-based mobile subscribers operating within a served cell, and between the base station and an aircraft flying through the served cell, said antenna arrangement comprising:

means for generating a horizontal antenna beam through which signals are transmitted and received between the base station and the ground-based subscribers; and

means for generating an elevated antenna beam through which signals are transmitted and received between the base station and the aircraft.

2. The antenna arrangement according to claim 1, wherein the elevated antenna beam is sufficiently separated in elevation from the horizontal antenna beam to eliminate mutual interference between the two beams.

3. The antenna arrangement according to claim 2, wherein a peak of the horizontal antenna beam is directed at zero degrees elevation, and a peak of the elevated antenna beam is directed at 30 degrees elevation.

4. The antenna arrangement according to claim 2, wherein the same frequency spectrum is used in the horizontal antenna beam and the elevated antenna beam.

5. An antenna arrangement in a cellular base station for transmitting and receiving signals between the base station and an aircraft flying through a cell served by the base station, said antenna arrangement comprising:

a vertically oriented array of antenna elements; and

a feedline arrangement connected to each of the antenna elements for feeding the antenna elements with progressively phase-retarded signals, thereby generating an elevated antenna beam directed upward toward the aircraft.

6. The antenna arrangement according to claim 5, wherein the feedline arrangement progressively feeds the antenna elements with 90-degree phase-retarded signals starting with a lowest antenna element and moving upwards, thereby generating an elevated antenna beam directed upwards at 30 degrees.

7. A method in a cellular base station for transmitting and receiving signals between the base station and ground-based mobile subscribers operating within a served cell, and between the base station and an aircraft flying through the served cell, wherein the base station includes an antenna arrangement having a vertically oriented array of antenna elements, said method comprising:

generating with the vertically oriented array of antenna elements, a horizontal antenna beam through which signals are transmitted and received between the base station and the ground-based subscribers; and

generating with the vertically oriented array of antenna elements, an elevated antenna beam through which signals are transmitted and received between the base station and the aircraft.

8. The method according to claim 7, wherein the elevated antenna beam is sufficiently separated in elevation from the horizontal antenna beam to eliminate mutual interference between the two beams.

9. The method according to claim 8, wherein:

the step of generating a horizontal antenna beam includes generating a horizontal antenna beam with a peak directed at zero degrees elevation; and

the step of generating an elevated antenna beam includes generating an elevated antenna beam with a peak directed at 30 degrees elevation.

10. The method according to claim 8, wherein the same frequency spectrum is used in the horizontal antenna beam and the elevated antenna beam.

11. A method in a cellular base station for transmitting and receiving signals between the base station and an aircraft flying through a cell served by the base station, said method comprising:

orienting a plurality of antenna elements into a vertical array;

connecting a feedline arrangement to each of the antenna elements; and

feeding the antenna elements with progressively phase-retarded signals, thereby generating an elevated antenna beam directed upward toward the aircraft.

12. A cellular communications system for communicating with ground-based mobile subscribers located within a service region and with an aircraft flying through the service region, wherein the service region is provided with a plurality of ground-based antenna towers spaced at intervals, each of said antenna towers serving a cell within the service region, said system comprising:

means for sending communication signals from a communications network to the plurality of antenna towers; and

an antenna arrangement located on at least one of the antenna towers, comprising;

means for generating azimuthally-spaced horizontal antenna beams for communicating with the ground-based subscribers; and

means for generating azimuthally-spaced elevated antenna beams separated in the vertical plane from the horizontal antenna beams for communicating with the aircraft.

13. The system according to claim 12, wherein the means for generating azimuthally-spaced horizontal antenna beams generates horizontal antenna beams having a vertical beam width wherein communications with the ground-based subscribers does not cause significant interference to communications with the aircraft.

14. The system according to claim 13, wherein the means for generating azimuthally-spaced elevated antenna beams generates elevated antenna beams having a vertical beam width wherein communications with the aircraft does not cause significant interference to communications with the ground-based subscribers.

15. The system according to claim 14, wherein the same frequency spectrum is used in the horizontal antenna beams and the elevated antenna beams.

16. The system according to claim 15, wherein the antenna arrangement generates azimuthally-spaced horizontal and elevated antenna beams in azmuthal sectors of a served cell, and the frequency spectrum is partitioned between the sectors of the azimuthally-spaced horizontal antenna beams, and is also partitioned between the azimuthal sectors of at least one of the elevated antenna beams.

17. The system according to claim 16, wherein the partitioning of the frequency spectrum between the azimuthal sectors of the horizontal antenna beams is rotated in comparison to the partitioning between the azimuthal sectors of the at least one elevated antenna beam, wherein in any one sector, the horizontal antenna beam and the elevated antenna beam used different frequency spectrums.

18. The system according to claim 12, wherein the cellular communications system is a GSM/EDGE cellular communications system.

19. The system according to claim 12, wherein the cellular communications system is a Code Division Multiple Access (CDMA) cellular communications system.

20. The system according to claim 19, wherein the same frequency spectrum is used in all antenna beams from the same tower.

21. The system according to claim 20, wherein transmissions from different beams of the same tower use orthogonal CDMA codes.

22. The system according to claim 12, wherein the means for sending communication signals from a communications network to the plurality of antenna towers includes:

means for sending communication signals from a first communications network to the antenna arrangement for communicating with the ground-based subscribers; and

means for sending communication signals from a second, different communications network to the antenna arrangement for communicating with the aircraft.

23. The system according to claim 12, wherein the antenna arrangement is located on a plurality of antenna towers, and the system further comprises a controller for tracking the aircraft and assigning the aircraft to operate via an antenna tower providing the highest quality signal.

24. The system according to claim 23, wherein the controller also hands off the aircraft from a first antenna tower to a second antenna tower when the aircraft moves from a first cell to a second cell served by the first and second antenna towers, respectively.

25. The system of claim 12, further comprising a power control mechanism for controlling transmission power levels for a ground transmitter at the antenna tower and an airborne transmitter utilized by the aircraft, wherein the power control mechanism ensures that both the ground transmitter and the airborne transmitter transmit at a power level sufficient for transmitted signals to reach only between the aircraft and the nearest antenna tower.

26. The system of claim 12, further comprising a power control mechanism for ensuring that the same transmission power level is utilized to transmit signals in the elevated antenna beams as is utilized to transmit signals in the horizontal antenna beams.

27. The system according to claim 12, wherein the means for sending communication signals from a communications network to the plurality of antenna towers includes means for sending a wideband multi-media communication signal to the antenna arrangement, wherein the antenna arrangement transmits the wideband multi-media communication signal in an elevated antenna beam to the aircraft.

28. A cellular communications system for communicating with ground-based mobile subscribers located within a cell and with an aircraft flying through the cell, said system comprising:

a ground-based base station serving the cell, said ground-based base station including an antenna arrangement for generating an elevated antenna beam for communicating with the aircraft;

a transceiver onboard the aircraft for communicating with the ground-based base station; and

a microcellular base station connected to the transceiver for communicating with portable communication devices onboard the aircraft.

29. The system according to claim 28, wherein the ground-based base station receives information from an air traffic control (ATC) network and from a cellular telecommunications network, said ground-based base station including a multiplexer for multiplexing information from the ATC network with information from the cellular network into a data stream sent to the aircraft with the elevated antenna beam.

30. The system according to claim 29, further comprising a multiplexer onboard the aircraft for de-multiplexing the data stream to separate the ATC information from the cellular information, wherein the cellular information is sent to the microcellular base station for retransmission to the portable communication devices.

31. The system according to claim 30, further comprising a codec for decoding the data stream received from the ground-based base station, and for recoding the cellular information in a format utilized by the portable communication devices.

32. The system according to claim 31, wherein the multiplexer sends the ATC information to cockpit instruments, and the codec recodes the ATC information in a format utilized by the cockpit instruments.