Technique for controlling a beam pattern employed by an antenna apparatus
A technique is provided for controlling a beam pattern employed by an antenna apparatus. The antenna apparatus comprises an antenna array, and beamforming circuitry to employ a beam pattern in order to generate a beam using the antenna array to facilitate wireless communication with at least one further antenna apparatus. Beam pattern adjustment circuitry is then arranged to receive a control signal indicative of a motion being imparted to the antenna apparatus, and to adjust the beam pattern to be used by the beamforming circuitry in dependence on the control signal, so as to alter a width of the beam in order to mitigate variation in link quality of the wireless communication due to the motion. This hence allows the width of the beam deployed by the antenna apparatus to be adjusted taking into account motion being imparted to the antenna apparatus, so that a balance can be achieved between employing a narrow beam to seek to improve range and resilience to interference, and a wider beam to reduce the variation in link quality that might otherwise arise due to the motion.
1. An antenna apparatus comprising:
an antenna array;
beamforming circuitry to employ a beam pattern in order to generate a beam using the antenna array to facilitate wireless communication with at least one further antenna apparatus; and
beam pattern adjustment circuitry to receive control signals indicative of a motion being imparted to the antenna apparatus, and to adjust the beam pattern to be used by the beamforming circuitry in dependence on the received control signals, so as to alter a width of the beam in order to mitigate variation in link quality of the wireless communication due to the motion;
wherein in response to an indication of an interruption in reception of received motion indication data used to generate the control signals, the beam pattern adjustment circuitry is configured to adjust the beam pattern to be used by the beamforming circuitry to a default beam pattern.
2. The antenna apparatus as claimed in claim 1 , wherein:
the indication comprises an interruption in reception of the control signals.
3. The antenna apparatus as claimed in claim 1 , wherein:
the indication comprises a form of the received control signal indicating that the motion indication data has not been received.
4. The antenna apparatus as claimed in claim 1 , wherein:
in response to an indication that reception of the received motion indication data has resumed, the beam pattern adjustment circuitry is configured to resume adjusting the beam pattern to be used by the beamforming circuitry in dependence on the received control signals.
5. The antenna apparatus as claimed in claim 1 , wherein:
the default beam pattern produces a beam having a width greater than a predetermined width.
6. The antenna apparatus as claimed in claim 1 , wherein:
the indication indicates that the interruption in reception of the received motion indication data has exceeded a predetermined time.
7. The antenna apparatus as claimed in claim 1 , wherein:
when the employed beam pattern produces a beam having a first width, the beam pattern adjustment circuitry is arranged to be responsive to the received control signals indicating motion that is considered to cause a variation in link quality exceeding a chosen threshold, to adjust the employed beam pattern such that the beam produced has a second width greater than the first width.
8. The antenna apparatus as claimed in claim 7 , wherein:
when the employed beam pattern produces a beam having the second width, the beam pattern adjustment circuitry is arranged to be responsive to the received control signals indicating motion that is considered to cause a variation in link quality below the chosen threshold, to adjust the employed beam pattern such that the beam produced has the first width.
9. The antenna apparatus as claimed in claim 7 , wherein the beam pattern adjustment circuitry is arranged to be responsive to a plurality of thresholds associated with corresponding variations in link quality, and to adjust the employed beam pattern so as to adjust the beam width in dependence on each threshold being passed.
10. The antenna apparatus as claimed in claim 7 , wherein the beam pattern adjustment circuitry is arranged to trigger adjustment of the employed beam pattern when a sequence of values of the received control signals indicate that the chosen threshold has been passed.
11. The antenna apparatus as claimed in claim 10 , wherein the beam pattern adjustment circuitry is arranged to maintain a counter value to track occurrences of values of the received control signals that indicate that the chosen threshold has been passed, and to trigger adjustment of the employed beam pattern in dependence on the counter value.
12. The antenna apparatus as claimed in claim 7 , wherein the value of the control signals that is associated with the chosen threshold differs depending on whether the motion is increasing or decreasing.
13. The antenna apparatus as claimed in claim 1 , further comprising:
storage to identify a plurality of beam patterns used to produce different width beams; and
the beam pattern adjustment circuitry is arranged to select from the plurality of beam patterns a current beam pattern to be employed by the beamforming circuitry, dependent on the received control signals.
14. The antenna apparatus as claimed in claim 1 , wherein the received control signals used by the beam pattern adjustment circuitry are indicative of the motion over a period of time.
15. The antenna apparatus as claimed in claim 1 , further comprising:
control signal generation circuitry arranged to generate the control signals dependent on the received motion indication data.
16. The antenna apparatus as claimed in claim 15 , wherein the received control signals used by the beam pattern adjustment circuitry are indicative of the motion over a period of time, and the control signal generation circuitry is arranged to generate the control signals such that a current value of each control signal is dependent on motion indication data indicative of motion at a plurality of points in time.
17. The antenna apparatus as claimed in claim 15 , further comprising:
at least one motion sensor to detect the motion being imparted to the antenna apparatus, and the control signal generation circuitry is arranged to determine the control signals provided to the beam pattern adjustment circuitry based on movement data produced by the at least one motion sensor.
18. The antenna apparatus as claimed in claim 17 , wherein the at least one motion sensor comprises at least a sensor to detect a twisting motion imparted to the antenna apparatus.
19. The antenna apparatus as claimed in claim 17 , wherein the at least one motion sensor comprises one or more of a magnetometer and an accelerometer.
20. The antenna apparatus as claimed in claim 17 , wherein the control signal generation circuitry comprises filtering circuitry to apply a filtering operation to determine the control signals based on the movement data received at multiple points in time.
21. The antenna apparatus as claimed in claim 20 , wherein the filtering circuitry is arranged to produce the control signals from a filtered movement data value d(k), where k is a sampling time, by performing the following computation:
d ( k )=ρ up ·d ( k− 1)+(1−ρ up )· z ( k ), if z ( k )> d ( k− 1)
and
d ( k )=ρ down ·d ( k− 1)+(1−ρ down )· z ( k ), otherwise,
where z(k) denotes an item of movement data at sampling time k, ρ up is a first chosen value between 0 and 1, and ρ down is a second chosen value between 0 and 1.
22. The antenna apparatus as claimed in claim 20 , wherein the filtering circuitry is also arranged to receive an indication of observed variation in link quality, for use in determining the control signals.
23. The antenna apparatus as claimed in claim 22 , wherein the observed variation in link quality is used by the filtering circuitry to influence a decision, based on the movement data, as to when to adjust the beam pattern so as to widen the beam produced.
24. The antenna apparatus as claimed in claim 1 , further comprising:
a lookup table structure referenced by the beam pattern adjustment circuitry to determine a form of beam pattern to be employed having regard to the received control signals.
25. The antenna apparatus as claimed in claim 1 , wherein the control signals are indicative of an oscillating motion caused by an environmental influence.
26. The antenna apparatus as claimed in claim 25 , wherein the oscillating motion results from vibration of a mounting structure to which the antenna apparatus is fixed.
27. A method of controlling a beam pattern employed by an antenna apparatus using an antenna array, comprising:
using beamforming circuitry to employ the beam pattern in order to generate a beam using the antenna array to facilitate wireless communication with at least one further antenna apparatus;
receiving control signals indicative of a motion being imparted to the antenna apparatus;
adjusting the beam pattern to be used by the beamforming circuitry in dependence on the received control signals, so as to alter a width of the beam in order to mitigate variation in link quality of the wireless communication due to the motion; and
in response to an indication of an interruption in reception of received motion indication data used to generate the control signals, adjusting the beam pattern to be used by the beamforming circuitry to a default beam pattern.
28. An antenna apparatus comprising:
antenna array means;
beamforming means for employing a beam pattern in order to generate a beam using the antenna array means to facilitate wireless communication with at least one further antenna apparatus; and
beam pattern adjustment means for receiving control signals indicative of a motion being imparted to the antenna apparatus, and for adjusting the beam pattern to be used by the beamforming means in dependence on the received control signals, so as to alter a width of the beam in order to mitigate variation in link quality of the wireless communication due to the motion;
wherein in response to an indication of an interruption in reception of received motion indication data used to generate the control signals, the beam pattern adjustment means is configured to adjust the beam pattern to be used by the beamforming means to a default beam pattern.