IWR1642BOOST: question about maximum range in 'Traffic Monitoring Object Detection and Tracking' example

Hello,

I have a question about 'TI Designs: TIDEP-0090; Traffic Monitoring Object Detection and Tracking Reference Design Using Single-Chip mmWave Radar Sensor' document. 

The above table is a copy from the mentioned document.

For Medium-Range MIMO example, using the provided parameters, I think the maximum range should be 38.94m instead of 70m. 

My calculation is shown as follows:

maximum beat frequency = 1/2 * ADC sampling rate; (from Nyquist criterion)

maximum range = speed of light * maximum beat frequency * sweep duration / (2 * sweep bandwidth);

then I got maximum range equals to 38.94m.

My question is: how can we get maximum range equals to 70m with the provided parameters?

Thanks in advance.

Regards,

Jiadi