AWR6843AOP: Questions about Beamforming and .cfg File Configuration for AWR6843AOP

Hsiu Che Chang

Part Number: AWR6843AOP

Tool/software:

Dear Sir,

The MMWAVE SDK User Guide states that I can perform a phase shift on three TX antennas by changing the <txPhaseShifter> parameter in the configuration file.

Furthermore, the document "Beamforming_in_LRPD.pdf" provides a MATLAB script as an example for calculating the <txPhaseShifter> parameter necessary for beamforming, using a one-dimensional antenna array indexed as m_ind = [0 1 2].

If I want to implement beamforming on the AWR6843AOP as well, I am wondering if there is a similar MATLAB script available to calculate the control numbers for the AWR6843AOP antenna array.

Sincerely,

HC.Chang

10 months ago

0 Clinton Rodgers 10 months ago

TI__Genius 13235 points

Hi,

Could you provide links and/or install paths to the documents you are referring to?

Thanks,

Clinton

0 Hsiu Che Chang 10 months ago in reply to Clinton Rodgers

Prodigy 30 points

Dear sir:

The MMWAVE SDK User Guide's path is: C:/ti/mmwave_studio_02_01_01_00/docs/mmwave_studio_cascade_user_guide.pdf

And the link of Beamforming in LRPD is: https://dev.ti.com/tirex/explore/node?a=1AslXXD__1.20.00.11&node=A__AE-Bpc-wQfi-OR.2V9TzCw__radar_toolbox__1AslXXD__1.20.00.11&r=1AslXXD__1.00.00.26&r=1AslXXD__1.00.01.07

Sincerely,

HC.Chang

0 Tim Henderson 9 months ago in reply to Hsiu Che Chang

TI__Expert 8782 points

Hello,

For the AOP device, we provide the layout of our antenna patterns also in the radar toolbox:

https://dev.ti.com/tirex/explore/node?node=A__AEHBDXaS3MIoORQMpX07MQ__radar_toolbox__1AslXXD__LATEST

You'll have to modify matlab script to work with such antenna pattern.

Regards,

Tim

0 Hsiu Che Chang 9 months ago in reply to Tim Henderson

Prodigy 30 points

Dear Tim,

Here is the MATLAB script we adjusted for calculating the phase shift based on the AWR6843AOPEVM antenna. Could you help us verify if the calculated phase shift control parameters are correct?

clear;

clc;

f = 60e9;

c = 3e8;

lambda = c / f;

k = 2 * pi / lambda;

dx = lambda;

dy = lambda;

phi_deg = input('Phi（degree）：');

theta_deg = input('Theta（degree）：');

phi = deg2rad(phi_deg);

theta = deg2rad(theta_deg);

I = [1 1; 1 0];

phase_shifts = zeros(2, 2);

for m = 0:1

for n = 0:1

x = m * dx;

y = n * dy;

phase_shifts(m+1, n+1) = k * (x * sin(theta) * cos(phi) + y * sin(theta) * sin(phi));

end

phase_shifts_deg = rad2deg(phase_shifts);

phase_shifts_deg_wrap = mod(phase_shifts_deg, 360);

phaseInc = 5.625;

phase_control = round(phase_shifts_deg_wrap / phaseInc);

combined_control = phase_control(1,1) * 2^0 + phase_control(1,2) * 2^8 + ...

phase_control(2,1) * 2^16;

packed_control = combined_control * 4;

disp('Phase control number:');

disp(num2str(packed_control, '%d'));

fprintf('Phase shifts (degrees):\n');

fprintf('tx1 (0, lambda): %f\n', phase_shifts_deg_wrap(1,2));

fprintf('tx2 (lambda, 0): %f\n', phase_shifts_deg_wrap(2,1));

fprintf('tx3 (0, 0): %f\n', phase_shifts_deg_wrap(1,1));

fprintf('tx4 (lambda, lambda) [DISABLED]: %f\n', phase_shifts_deg_wrap(2,2));

phi_vals = linspace(0, 2*pi, 360);

theta_vals = linspace(0, pi, 180);

[Phi, Theta] = meshgrid(phi_vals, theta_vals);

AF = zeros(size(Phi));

for i = 1:size(Phi, 1)

for j = 1:size(Phi, 2)

af_sum = 0;

for m = 0:1

for n = 0:1

if I(m+1, n+1) == 1

adjusted_phase = k * (m * dx * sin(Theta(i,j)) * cos(Phi(i,j)) + n * dy * sin(Theta(i,j)) * sin(Phi(i,j))) - phase_shifts(m+1, n+1);

af_sum = af_sum + I(m+1, n+1) * exp(1j * adjusted_phase);

end

AF(i, j) = abs(af_sum);

end

AF = AF / max(AF(:));

AF_dB = 20 * log10(AF);

AF_dB(AF_dB < -40) = -40;

figure;

[X, Y, Z] = sph2cart(Phi, pi/2 - Theta, AF);

surf(X, Y, Z, AF_dB);

title(sprintf('Radiation Pattern at Phi = %d°, Theta = %d°', phi_deg, theta_deg));

xlabel('X');

ylabel('Y');

zlabel('Z');

shading interp;

colorbar;

colormap jet;

view(140, 30);

hold on;

plot3([0 max(X(:))], [0 0], [0 0], 'k--', 'LineWidth', 1);

plot3([0 0], [0 max(Y(:))], [0 0], 'k--', 'LineWidth', 1);

plot3([0 0], [0 0], [0 max(Z(:))], 'k--', 'LineWidth', 1);

text(max(X(:)), 0, 0, ' \phi=0', 'HorizontalAlignment', 'right');

text(0, 0, max(Z(:)), ' \theta=0', 'HorizontalAlignment', 'right');

Best regards,

Hsiu-Che Chang

0 Kristien Everett 9 months ago in reply to Hsiu Che Chang

TI__Genius 9865 points

Hello,

Just a heads up, most of our engineers will be out until July 8th due to a United States holiday. If you have any updates or questions, please hold off on replying until next week when we can respond to you then. We will also try to get back to you next week as well.

Thank you for your patience,

Kristien

0 Clinton Rodgers 8 months ago in reply to Kristien Everett

TI__Genius 13235 points

Hi,

I wanted to check to see if you were able to move forward on your project.

Thanks,

Clinton

0 Hsiu Che Chang 8 months ago in reply to Clinton Rodgers

Prodigy 30 points

Dear Clinton,

As mentioned previously, we still need to verify whether the phase shifter parameters calculated by our proposed MATLAB script can correctly control the AWR6843AOP for phase shifting.
My MATLAB script is as follows:

Best Regards,

Hsiu-Che Chang

0 Clinton Rodgers 8 months ago in reply to Hsiu Che Chang

TI__Genius 13235 points

Hi,

Have you tried using the results of your calculations and observed the behavior of the device? Is it not working as you expect?

Thanks,

Clinton

0 Hsiu Che Chang 8 months ago in reply to Clinton Rodgers

Prodigy 30 points

Hi Clinton,

After enabling the TX phase shift, we initially intended to perform beamsteering on the TX array to improve the point cloud resolution for adults and children. However, the current experimental results show that after changing the phase shift parameters, firstly, the point cloud at the main beam position did not improve, and secondly, the points in the point cloud exhibit a deviation issue.

Best,

Hsiu-Che Chang

0 zigang Yang 8 months ago in reply to Hsiu Che Chang

TI__Mastermind 38235 points

Hi, Hsiu-Che:

Our understanding is TX beamforming can increase the SNR, but do not really improve the angle resolution.

From our TX beamforming notes https://dev.ti.com/tirex/explore/node?node=A__AE-Bpc-wQfi-OR.2V9TzCw__radar_toolbox__1AslXXD__LATEST, we provided an example of phase rotation for one-dimensional antenna.

theta_desired = -33.75;

m_ind = [0 1 2]; % antenna distance in unit of lambda in the azimuth direction

phaseTX_rad = 2*pi*(m_ind*sind(theta_desired));

For two-dimensional TX antenna layout, you can consider the following code.

theta_desired = -33.75; %desired beam focus-angle in azimuth direction

thetaE_desired = 20; % desired beam focus-angle in elevation direction

m_ind = [0 1 2]; % antenna distance in unit of lambda in the azimuth direction

n_ind = [ 0 1/2 0]; % antenna distance in unit of lambda in the elevation direction

phaseTX_rad = 2*pi*(m_ind*sind(theta_desired)*cosd(thetaE_desired) + n_ind*sind(thetaE_desired));

Note that this is not used in any of our formal release code, because we never try TX beamforming with AWR6843AOP or AWR6843ISK-ODS type of antenna. You can use this code at your own risk.

Other than this, we can not help you with any code review/debug.

Best,

Zigang

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AWR6843AOP: Questions about Beamforming and .cfg File Configuration for AWR6843AOP