US 12,174,311 B2
Empty band doppler division multiple access
Anil Varghese Mani, Bangalore (IN); Sandeep Rao, Bangalore (IN); and Dan Wang, Allen, TX (US)
Assigned to TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US)
Filed by TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US)
Filed on Sep. 3, 2021, as Appl. No. 17/466,867.
Prior Publication US 2023/0072441 A1, Mar. 9, 2023
Int. Cl. G01S 7/02 (2006.01); G01S 13/58 (2006.01)
CPC G01S 7/0232 (2021.05) [G01S 13/583 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A non-transitory processor-readable medium storing instructions executable by one or more processors in a radar system, the instructions comprising instructions for:
modulating each of a plurality of transmitters of the radar system with a corresponding phase shift that is a function of the corresponding transmitter and a number of the plurality of transmitters;
transmitting, via the plurality of transmitters, frames of chirps, wherein each transmitter of the plurality of transmitters applies the corresponding phase shift to the chirps of the frame of chirps transmitted by the corresponding transmitter;
receiving, via a receiver of the radar system, reflected signals based on the transmitted chirps having been reflected by an object within a field of view of the radar system; and
determining, in a frequency domain, a Doppler representation of the reflected signals, the Doppler representation having a Doppler spectrum that includes multiple spectrum bands, wherein a relationship used to determine the phase shift of each of the plurality of transmitters is determined by

OG Complex Work Unit Math
where k is an index value identifying a corresponding transmitter transmitting the corresponding frame of chirps, N is the number of the plurality of transmitters, a is a constant integer, and r is a number of empty spectrum bands in the Doppler representation, in which the relationship is configured to cause the Doppler spectrum to include a number of spectrum bands greater than the number of the plurality of transmitters and to include at least one empty spectrum band of the multiple spectrum bands in which the object is not present.