Frequency Domain MIMO For FMCW Radar

A method for transmitting and receiving signal for an automotive vehicle radar system, the method comprising:

• generating a plurality of chirp signals with each of the chirp signals having a frequency characteristic such that the chirp signals linearly increase in frequency from a first predetermined frequency at a first point in time to a second predetermined frequency at a second point in time, wherein the first predetermined frequency of each of the plurality of chirp signals is different;
• transmitting the plurality of chirp signals through a like plurality of transmit antennas;
• receiving a plurality of return chirp signals at a plurality of receive antennas, wherein each of the plurality of transmit antennas are paired with at least one of the plurality of receive antennas as a transmit reference;
• at each of the plurality of receive antennas,
• comparing one or more of the plurality of return chirp signals to one or more oscillator signals, each of the one or more oscillator signals corresponding to the transmit reference of the respective one of the plurality of receive antennas;
• determining an intermediate frequency for each of the one or more of the plurality of return chirp signals, wherein the intermediate frequency corresponds to a difference between a respective return chirp signal and a respective one of the one or more oscillator signals;
• and
• identifying a respective one of the plurality of transmit antennas that transmitted the one or more of the plurality of received signals.

In an automotive radar system, a sensor comprising:

• a multiple input multiple output (MIMO) transmitter comprising:
• a plurality of means for emitting;
• a like first plurality of transmit signal paths, each of the transmit signal paths having an input and an output with the output coupled to a corresponding one of said plurality of means for emitting;
• a first means for generating radiofrequency (RF) chirp signals to each of the transmit signal paths, wherein each RF signal path receives a corresponding one of a like plurality of RF chirp signals with each of said chirp signals having a frequency which linearly changes from a first frequency to a second, different frequency, and wherein each of the plurality of RF chirp signals has a different first frequency;
• and
• a MIMO receiver comprising:
• a plurality of means for receiving;
• and
• a like second plurality of receive signal paths, each of said receive signal paths having input coupled to a corresponding one of said means for receiving and coupled to receive a portion of a respective one of said RF chirp signals such that each of said receive signal paths receive a portion of a corresponding one of the RF chirp signal provided to each of said plurality of RF transmit paths.