AWR1843BOOST: What are the other differences between Beam Steering and non Beam Steering ?

Mostafa Besar

Part Number: AWR1843BOOST
Other Parts Discussed in Thread: AWR1642

Hello,

Is the only difference between Beam Steering and non Beam Steering the max range becomes greater in Beam Steering after +/-40 deg?

Are there any differences?

Thanks,

over 4 years ago

0 Aniket Mahajan over 4 years ago

TI__Genius 15046 points

Hi Mostafa,

Apart from this, since beamforming is used, all three antennas transmit together. This reduces the number of virtual antennas from numRx*numTx to numRx. This will reduce the angle resolution. Apart from this, there should not be any fundamental differences.

Regards,

Aayush

0 Mostafa Besar over 4 years ago in reply to Aniket Mahajan

Intellectual 470 points

Hello Aayush,

Could you explain me what's meaning of this statement?

Aniket Mahajan said:
This reduces the number of virtual antennas from numRx*numTx to numRx

Thanks,

Mostafa

+1 Aniket Mahajan over 4 years ago in reply to Mostafa Besar

TI__Genius 15046 points

Hi,

We usually operate the radar by turning on 1TX at a time for each chirp. So TX transmissions would look like: chirp0(TX0) chirp1(TX1) chirp2(TX2) chirp3(TX0), ....

If only 1TX were used, the angle resolution would depend on the number of receiving antennae, roughly speaking. With the sequence of chirps I described above, we can get better performance, as we end up creating virtual antennae. This is the TDM-MIMO (time division multiplexing, multiple-in, multiple-out) concept.

With 4Rx and 2Tx working, we get the same angular resolution performance as we would have if we had 8 Rx antenna and 1Tx.

With beamsteering, we don't get this MIMO advantage, as all TXs transmit at the same time.

I know my explanation above isn't comprehensive. We have some good resources that cover the MIMO topic in the radar context in more detail:

Introduction to mmWave radar sensing: FMCW radars training series

The fundamentals of millimeter wave radar sensors App Note

MIMO Radar App Note

Regards,

Aayush

0 Mostafa Besar over 4 years ago in reply to Aniket Mahajan

Intellectual 470 points

Hello Aayush,

Thanks for this information.

I read a part of MIMO Radar App Note and I come up with:

Is Beamsteering uses BPM-MIMO? if not why beamsteering doesn't use the advantage of BPM-MIMO which able to turn on all TX antennas as same time slot ? unlike TDM MIMO which turn on just on TX at one time slot.

Thanks & Regards

Mostafa

0 Aniket Mahajan over 4 years ago in reply to Mostafa Besar

TI__Genius 15046 points

Hi Mostafa,

The purpose of the lab was to demonstrate beamforming and beamsteering. To form a beam at a particular angle, you need to have the TX programmed at particular phase shifts. These phase shifts do not correspond to the phase shifts needed by the BPM scheme, hence, we can't have both beamsteering and BPM.

So, while we could have used BPM to enable all TXs (and we have a configuration for that in the AWR1642 out of box demo), this would not give us beamforming.

When we use beamforming, the dB gain is even higher than if we simply enable multiple the TXs under BPM scheme.

Regards,

Aayush

0 Mostafa Besar over 4 years ago in reply to Aniket Mahajan

Intellectual 470 points

Hello,

So the only advantages of Beam steering in mmWave radars is good ranges in maximum angles?

Thanks,

Mostafa,

0 Aniket Mahajan over 4 years ago in reply to Mostafa Besar

TI__Genius 15046 points

Hi Mostafa,

That is correct.

Regards,

Aayush

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AWR1843BOOST: What are the other differences between Beam Steering and non Beam Steering ?