Terrestrial based air-to-ground communications system and related methods
An air-to-ground communications system includes at least one base station to be positioned on the ground and including a ground-based transceiver, a phased array antenna coupled to the ground-based transceiver, and a beamforming network coupled to the ground-based transceiver. The ground-based transceiver is configured to provide data traffic and control information to an aircraft. The beamforming network is configured to simultaneously generate at least one narrow antenna beam for the data traffic and at least one wide beam for the control information.
1. A base station of an air-to-ground (ATG) communications system, the base station being configured to communicate with an in-flight aircraft of the ATG communications system, the base station comprising:
a ground-based transceiver;
a ground-based controller operably coupled to the ground-based transceiver; and
a beamforming network operably coupled to the ground-based controller,
wherein the beamforming network is configured to generate a plurality of fixed narrow antenna beams that are formed using unlicensed band frequencies of either from 2.4 GHz to 2.5 GHz or 5.725 GHz to 5.875 GHz,
wherein the narrow antenna beams are each associated with communication of data traffic,
wherein the beamforming network is configured to:
responsive to establishment of access to the aircraft, track position information via a return link from the aircraft, the position information being indicative of aircraft position, and
successively handover communication equipment on the aircraft between respective adjacent ones of the narrow antenna beams based on the position information to communicate the data traffic with the communication equipment on the aircraft,
wherein the establishment of access is performed based on an autonomous time advance determined at the aircraft, and
wherein responsive to a handover event, a new time advance update is provided to the aircraft by the base station prior to the aircraft providing the position information via a line of bearing signal defining a relative position of the aircraft in relation to the base station.
2. The base station of claim 1 , wherein the beamforming network further generates a wide antenna beam that overlaps with at least some of the narrow antenna beams, and
wherein the wide antenna beam is at least four times a width of each of the narrow antenna beams.
3. The base station of claim 1 , further comprising a plurality of wide antenna beams, each of the wide antenna beams corresponding to a sector of the base station, wherein each sector of the base station further comprises a corresponding plurality of fixed narrow antenna beams that are configured to be activated sequentially based on the position information.
4. The base station of claim 1 , wherein the position information is provided via a line of bearing signal defining a relative position of the aircraft in relation to the base station.
5. The base station of claim 4 , wherein the line of bearing signal is updated periodically based on a triggering event.
6. The base station of claim 5 , wherein the triggering event comprises expiration of a previously received line of bearing signal.
7. The base station of claim 5 , wherein the triggering event comprises an indication of high mobility between the aircraft and the base station.
8. An air-to-ground communications system comprising:
a plurality of base stations, each comprising a ground-based transceiver and associated ground-based controller, the base stations being capable of communication with an aircraft having an aircraft-based transceiver and associated aircraft-based controller; and
a beamforming network operably coupled to the ground-based controller at each of the base stations,
wherein the beamforming network is configured to generate a plurality of fixed narrow antenna beams that are formed using unlicensed band frequencies of either from 2.4 GHz to 2.5 GHz or 5.725 GHz to 5.875 GHZ,
wherein the narrow antenna beams are each associated with communication of data traffic and have a beamwidth of less than 8 degrees,
wherein the beamforming network is configured to:
responsive to establishment of access to the aircraft, track position information via a return link from the aircraft, the position information being indicative of aircraft position, and
successively handover communication with the aircraft-based transceiver between respective adjacent ones of the narrow antenna beams based on the position information to communicate the data traffic with the communication equipment on the aircraft,
wherein the establishment of access is performed based on an autonomous time advance determined at the aircraft, and
wherein responsive to a handover event, a new time advance update is provided to the aircraft by the base station prior to the aircraft providing the position information is provided via a line of bearing signal defining a relative position of the aircraft in relation to one of the base stations.
9. The system of claim 8 , wherein the beamforming network further generates a wide antenna beam that overlaps with at least some of the narrow antenna beams, and wherein the wide antenna beam is at least four times a width of each of the narrow antenna beams.
10. The system of claim 8 , further comprising a plurality of wide antenna beams, each of the wide antenna beams corresponding to a sector of each of the base stations, wherein each sector of the base stations further comprises a corresponding plurality of fixed narrow antenna beams that are configured to be activated sequentially based on the position information.
11. The system of claim 8 , wherein the position information is provided via a line of bearing signal defining a relative position of the aircraft in relation to a currently serving one of the base stations.
12. The system of claim 11 , wherein the line of bearing signal is updated periodically based on a triggering event.
13. The system of claim 12 , wherein the triggering event comprises expiration of a previously received line of bearing signal.
14. The system of claim 12 , wherein the triggering event comprises an indication of high mobility between the aircraft and the currently serving one of the base stations.
15. The system of claim 8 , wherein the beamforming network further generates a wide antenna beam for control data that overlaps with at least some of the narrow antenna beams, the control data of the wide antenna beam being used for initial establishment of access to the aircraft.
16. The system of claim 8 , wherein additional base stations are included in the system to operate in unlicensed band frequencies including frequencies ranging from 824 MHz to 849 MHz and from 869 MHz to 894 MHz, and 1.9 GHz.