1 / 47

Beamforming

Beamforming. Tx1. Tx1. Tx2. Tx1. +. Tx2. Tx1. Rx. Destructive superimposition. Tx2. Tx1. Zero signal. +. Rx. Tx2. Tx1. Constructive superimposition. Amplified signal (twice amplitude). Tx2. Tx1. Receiver at arbitrary location. Rx. +.

summersh
Download Presentation

Beamforming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Beamforming

  2. Tx1

  3. Tx1

  4. Tx2 Tx1

  5. + Tx2 Tx1 Rx

  6. Destructive superimposition Tx2 Tx1 Zero signal

  7. + Rx Tx2 Tx1

  8. Constructive superimposition Amplified signal (twice amplitude) Tx2 Tx1

  9. Receiver at arbitrary location Rx + Tx2 Tx1

  10. Arbitrary location, what’s the path difference Path difference = ??

  11. Path difference Rx + Tx2 Tx1

  12. Path difference and phase difference Rx + Path difference = Tx2 Tx1

  13. Radiation pattern: Rx amplitude as a function of angle

  14. Radiation pattern: Rx amplitude as a function of angle

  15. Radiation pattern: Rx amplitude as a function of angle

  16. Radiation pattern: Rx amplitude as a function of angle +

  17. Radiation pattern: Rx amplitude as a function of angle The initial phases can be controlled +

  18. Radiation pattern: Rx amplitude as a function of angle + =0 =-x A non zero initial phase can change the radiation pattern =0 =-x

  19. Multiple antennas

  20. Rx . . . Tx2 Tx1 Tx(N) Tx(N-1) ……..

  21. +

  22. Radiation pattern

  23. Rotating the beam + + A maxima occurs in the direction of

  24. Rotating the beam

  25. Networking applications

  26. Acoustic Beamforming – noise suppression Silent zone Audible Zone

  27. Other applications • Localization • Gesture tracking • RF Imaging

  28. Reception

  29. Sensing Angle of Arrival (AoA) Tx Path difference = Rx1 Rx2

  30. Antenna array Tx . . . Rx2 Rx1 Rx(N) Rx(N-1)

  31. Steering vector

  32. Multiple transmitters Tx2 Tx1 . . . Rx2 Rx1 Rx(N) Rx(N-1)

  33. Multiple transmitters Output is a linear combination of steering vectors from different directions

  34. Multiple transmitters Steering Matrix (N x K) K sources (Input Vector) N receivers (Output vector)

  35. Detecting AoA of K sources simultaneously

  36. Multiply by conjugate of steering vector of source 1 .. ..

  37. ..

  38. A = .. All energy from direction have been aggregated and amplified

  39. A = .. All energy from direction have been aggregated and amplified

  40. A = .. The resultant output is very low .. since multiplied steering vector does not match with any of the incoming signals

  41. Construct a graph of for all values of • Any active source from direction should have a peak in the above graph .. • This is called delay and sum beamforming A

  42. Detecting multiple AoA A AoA Spectrum Suc

  43. Close by AoAs cannot be resolved

  44. MUSIC algorithm has sharp peaks to resolve close AoA Based on eigen decomposition and PCA – reference to be provided

  45. Degrees of freedom for beamforming • Antenna separation • Initial phases of antenna sources • Number of antennas

More Related