Mixed multiple input multiple output (MIMO) radar

1. A radar sensor, comprising:

one or more multiple input multiple output (MIMO) receivers configured to receive radar signals generated by a plurality of MIMO transmitters; and

control logic coupled to the one or more MIMO receivers, the control logic configured to decode the received radar signals using a mixture of sub-set digital codes that discriminate between a plurality of sub-sets of MIMO transmitters of the plurality of MIMO transmitters and Doppler-division codes that discriminate between different MIMO transmitters within each of the plurality of sub-sets of MIMO transmitters such that, for a particular MIMO transmitter of the plurality of MIMO transmitters, a sub-set digital code associated therewith identifies a particular sub-set to which the particular MIMO transmitter is assigned and a Doppler-division code associated therewith identifies the particular MIMO transmitter within the particular sub-set to which the particular MIMO transmitter is assigned.

2. The radar sensor of claim 1 , wherein the radar signals generated by the plurality of MIMO transmitters include a plurality of frequency modulated continuous wave (FMCW) chirps, and wherein the control logic is configured to, for a first MIMO receiver in the one or more MIMO receivers:

perform range transformation over a plurality of chirps received by the first MIMO receiver to generate slow time radar data;

demodulate the slow time radar data using sub-set digital codes associated with the plurality of sub-sets of MIMO transmitters to generate sub-set partitioned slow time radar data;

perform Doppler transformation on the sub-set partitioned slow time radar data to generate sub-set partitioned Doppler radar data; and

demodulate the sub-set partitioned Doppler radar data using Doppler-division codes for the transmitters within each of the plurality of sub-sets of MIMO transmitters.

3. The radar sensor of claim 1 , wherein the sub-set digital codes are pseudo-random digital codes selected from pseudo-random code sequences associated with each of the plurality of sub-sets of MIMO transmitters.

4. The radar sensor of claim 1 , wherein the plurality of MIMO transmitters are disposed on a plurality of MIMO radar transceiver devices, and wherein the MIMO transmitters disposed on each MIMO radar transceiver device are in the same sub-set of MIMO transmitters.

5. The radar sensor of claim 1 , wherein the control logic is further configured to generate the plurality of sub-sets of MIMO transmitters during runtime of the radar sensor.

6. The radar sensor of claim 1 , wherein the control logic is configured to reassign MIMO transmitters to sub-sets during runtime of the radar sensor in response to one or more runtime conditions.

7. The radar sensor of claim 1 , wherein the control logic is configured to decode a first radar signal generated by a first MIMO transmitter of the plurality of MIMO transmitters using a first sub-set digital code that identifies a first sub-set of the plurality of sub-sets of MIMO transmitters to which the first MIMO transmitter is assigned and a first Doppler-division code that identifies the first MIMO transmitter within the first sub-set.

8. The radar sensor of claim 1 , wherein the sub-set digital code associated with the particular MIMO transmitter defines a first phase shift, the Doppler-division code associated with the particular MIMO transmitter defines a second phase shift, and a phase shift of a chirp in a radar signal generated by the particular MIMO transmitter has a phase shift that is controlled to be a sum of the first and second phase shifts.

9. The radar sensor of claim 1 , wherein the control logic is further configured to identify one or more targets in a field of view of the radar sensor using the received radar signals decoded using the mixture of sub-set digital codes and Doppler-division codes.

10. The radar sensor of claim 1 , wherein the control logic is further configured to generate a point cloud for a field of view of the radar sensor using the received radar signals decoded using the mixture of sub-set digital codes and Doppler-division codes.

11. The radar sensor of claim 1 , wherein the received radar signals include reflected signals generated by reflection of transmitted radar signals transmitted by the plurality of MIMO transmitters off of one or more targets in a field of view of the radar sensor.

12. A radar sensor, comprising:

one or more multiple input multiple output (MIMO) receivers configured to receive radar signals generated by a plurality of MIMO transmitters, wherein the radar signals generated by the plurality of MIMO transmitters include a plurality of frequency modulated continuous wave (FMCW) chirps; and

control logic coupled to the one or more MIMO receivers, the control logic configured to decode the received radar signals using a mixture of sub-set digital codes that discriminate between a plurality of sub-sets of MIMO transmitters of the plurality of MIMO transmitters and Doppler-division codes that discriminate between different MIMO transmitters within each of the plurality of sub-sets of MIMO transmitters, and wherein the control logic is configured to, for a first MIMO receiver in the one or more MIMO receivers:

perform range transformation over a plurality of chirps received by the first MIMO receiver to generate slow time radar data;

demodulate the slow time radar data using sub-set digital codes associated with the plurality of sub-sets of MIMO transmitters to generate sub-set partitioned slow time radar data;

perform Doppler transformation on the sub-set partitioned slow time radar data to generate sub-set partitioned Doppler radar data; and

demodulate the sub-set partitioned Doppler radar data using Doppler-division codes for the transmitters within each of the plurality of sub-sets of MIMO transmitters.

13. The radar sensor of claim 12 , wherein the sub-set digital codes are pseudo-random digital codes selected from pseudo-random code sequences associated with each of the plurality of sub-sets of MIMO transmitters.

14. The radar sensor of claim 12 , wherein the plurality of MIMO transmitters are disposed on a plurality of MIMO radar transceiver devices, and wherein the MIMO transmitters disposed on each MIMO radar transceiver device are in the same sub-set of MIMO transmitters.

15. The radar sensor of claim 12 , wherein the control logic is further configured to generate the plurality of sub-sets of MIMO transmitters during runtime of the radar sensor.

16. The radar sensor of claim 12 , wherein the control logic is configured to reassign MIMO transmitters to sub-sets during runtime of the radar sensor in response to one or more runtime conditions.

17. The radar sensor of claim 12 , wherein the control logic is configured to decode a first radar signal generated by a first MIMO transmitter of the plurality of MIMO transmitters using a first sub-set digital code that identifies a first sub-set of the plurality of sub-sets of MIMO transmitters to which the first MIMO transmitter is assigned and a first Doppler-division code that identifies the first MIMO transmitter within the first sub-set.

18. The radar sensor of claim 12 , wherein the control logic is further configured to identify one or more targets in a field of view of the radar sensor using the received radar signals decoded using the mixture of sub-set digital codes and Doppler-division codes.

19. The radar sensor of claim 12 , wherein the control logic is further configured to generate a point cloud for a field of view of the radar sensor using the received radar signals decoded using the mixture of sub-set digital codes and Doppler-division codes.

20. The radar sensor of claim 12 , wherein the received radar signals include reflected signals generated by reflection of transmitted radar signals transmitted by the plurality of MIMO transmitters off of one or more targets in a field of view of the radar sensor.