Signaling in an orthogonal frequency division multiplexed radar system

1. A method comprising:

repeatedly transmitting, by a transmitter of a radar system during a first time interval, a first OFDM symbol into a scene to be characterized;

repeatedly transmitting, by the transmitter of the radar system during a second time interval that occurs after the first time interval, a second OFDM symbol into the scene;

generating, by a receiver of the radar system, a first channel response estimate for a first section of the scene based on: received reflections of the first OFDM symbol, at least one of which was received during transmission of the second OFDM symbol in the second time interval; and

generating, by the receiver of the radar system, a first channel response estimate for a second section of the scene based on:

the first channel response estimate for the first section of the scene;

received reflections of the first OFDM symbol; and

received reflections of the second OFDM symbol; and

detecting, by the receiver of the radar system, objects present in the scene based on the first channel response estimate for the first section of the scene and the first channel response estimate for the second section of the scene.

2. The method of claim 1 , comprising during a third time interval after the second time interval, generating, by the receiver of the radar system, a second channel estimate for the first section and a second channel estimate for the second section based on:

the first channel response estimate for the first section of the scene;

the first channel response estimate for the second section of the scene;

received reflections of the first OFDM symbol; and

received reflections of the second OFDM symbol.

3. The method of claim 2 , comprising during a fourth time interval after the third time interval, repeatedly transmitting, by the transmitter of the radar system, the first OFDM symbol into the scene.

4. The method of claim 1 , wherein:

the first section of the scene is between the radar system and a first boundary; and

the second section of the scene is between the first boundary and a second boundary that is farther from the radar system than the first boundary.

5. The method of claim 4 , comprising setting, by the radar system, duration of the first time interval based on length of the first section of the scene.

6. The method of claim 5 , comprising setting duration of the first time interval to be a round trip travel time of the first section of the scene.

7. A method comprising:

deciding, by radar system, a boundary of a first section of a scene to be characterized and a boundary of a second section of the scene to be characterized, wherein:

the boundary of the second section is farther than the boundary of the first section; and

the deciding the boundary of the first section and the boundary of the second section is based on a first characteristic of an object in the scene;

deciding, by the radar system, a quantity of OFDM symbols to repeatedly transmit into the scene, wherein:

the deciding the quantity of OFDM symbols is based on a second characteristic of an object in the scene; and

the second characteristic is the same as or different than the first characteristic,

repeatedly transmitting, by a transmitter of the radar system, a first of the OFDM symbols into the scene during a first time interval;

repeatedly transmitting, by the transmitter of the radar system, a second of the OFDM symbols into the scene during a second time interval;

generating, by a receiver of the radar system, a channel response estimate for the first section of the scene and a channel response estimate for a second section of the scene based on received reflections of the first of the OFDM symbols and the second of the OFDM symbols; and

detect, by the receiver of the radar system, objects present in the scene based on the channel response estimate for the first section of the scene and the channel response estimate for the second section of the scene.

8. The method of claim 7 , wherein the first characteristic of the object is one of speed and proximity of the object.

9. The method of claim 7 , wherein the second characteristic of the object is one of speed and proximity of the object.

10. The method of claim 7 , comprising setting, by the radar system, duration of the first time interval based on length of the first section of the scene.

11. The method of claim 10 , comprising setting the duration of the first time interval to be round trip travel time of the first section of the scene.

12. The method of claim 7 , wherein the generating the channel response estimate for the first section of the scene is based on: a reflection of the first symbol received during transmission of the second OFDM symbol in the second time interval.

13. The method of claim 12 , wherein the generating the channel response estimate for the second section of the scene is based on:

the channel response estimate for the first section of the scene;

received reflections of the first symbol; and

received reflections of the second symbol.

14. A system comprising:

a radar system comprising a transmitter and a receiver, wherein:

the radar system is operable to decide a boundary of a first section of a scene to be characterized and a boundary of a second section of the scene to be characterized;

the boundary of the second section is farther than the boundary of the first section; and

the decision of the boundary of the first section and the boundary of the second section is based on a first characteristic of an object in the scene;

the radar system is operable to decide a quantity of OFDM symbols to repeatedly transmit into the scene, wherein:

the decision of the quantity of OFDM symbols is based on a second characteristic of an object in the scene; and

the second characteristic is the same as or different than the first characteristic,

the transmitter is operable to:

repeatedly transmit a first of the OFDM symbols into the scene during a first time interval;

repeatedly transmit a second of the OFDM symbols into the scene during a second time interval;

the receiver is operable to:

generate a channel response estimate for the first section of the scene and a channel response estimate for a second section of the scene based on received reflections of the first of the OFDM symbols and the second of the OFDM symbols; and

detect objects present in the scene based on the channel response estimate for the first section of the scene and the channel response estimate for the second section of the scene.

15. The system of claim 14 , wherein the first characteristic of the object is one of speed and proximity of the object.

16. The system of claim 15 , wherein the second characteristic of the object is one of speed and proximity of the object.

17. The system of claim 16 , wherein the radar system is operable to set a duration of the first time interval based on length of the first section of the scene.

18. The system of claim 14 , wherein the radar system is operable to set duration of the first time interval to be round trip travel time of the first section of the scene.

19. The system of claim 14 , wherein the generation of the channel response estimate for the first section of the scene is based on: a reflection of the first OFDM symbol received during transmission of the second OFDM symbol in the second time interval.

20. The system of claim 19 , wherein the generation of the channel response estimate for the second section of the scene is based on:

the channel response estimate for the first section of the scene;

received reflections of the first OFDM symbol; and

received reflections of the second OFDM symbol.