Rapid doppler correction for mobile V2X communication in 5G/6G

1. A method for a mobile user device to communicate with a base station of a wireless network, the method comprising:

determining, by the mobile user device, a location of the base station, a location of the mobile user device using a satellite-based navigation system, a speed of the mobile user device using a speedometer mounted in or on the mobile user device, and a direction of travel of the mobile user device using an electronic compass mounted in or on the mobile user device;

determining, by the mobile user device, a channel frequency associated with the base station;

calculating, by the mobile user device, a Doppler frequency shift associated with wireless communication between the mobile user device and the base station, the Doppler frequency shift being proportional to the channel frequency and proportional to the speed of the mobile user device and proportional to a cosine of an angle between the direction of travel of the mobile user device and a direction toward the base station from the mobile user device; and

transmitting, by the mobile user device, to the base station, a first wireless message at a first frequency.

2. The method of claim 1 , wherein the message is transmitted according to 5G technology.

3. The method of claim 1 , wherein the first frequency is configured so that the first message is received, by the base station, at the channel frequency.

4. The method of claim 1 , wherein the first frequency is substantially equal to the channel frequency minus the Doppler frequency shift, wherein “substantially equal” refers to being “equal to within a predetermined fraction of the Doppler frequency shift”, and wherein the predetermined fraction is in the list of 1%, 5%, 10%, and 20%.

5. The method of claim 1 , further comprising receiving, by the mobile user device, from the base station, a second message at a second frequency substantially equal to the first frequency or to the channel frequency plus the Doppler frequency shift.

6. The method of claim 1 , further comprising receiving, by the mobile user device, from the base station, a second message at a second frequency substantially equal to the first frequency plus twice the Doppler frequency shift.

7. The method of claim 1 , further comprising receiving, by the mobile user device, information from a publicly accessible database of network properties, the information including the location of the base station.

8. The method of claim 1 , further comprising:

transmitting, by the mobile user device, to the base station, a third message specifying the location, speed, and direction of travel of the mobile user device.

9. The method of claim 8 , wherein the third message further includes a demodulation reference, a message-type code indicating that the third message includes the location, speed, and direction of travel of the mobile user device, and an identification code of the mobile user device.

10. The method of claim 9 , wherein the third message further includes an interval of unmodulated carrier signal.

11. A base station of a wireless network, in signal communication with a mobile user device, the base station configured to:

determine a channel frequency related to a channel of the base station;

determine a frequency shift related to a motion of the mobile user device, wherein the frequency shift is based at least in part on the speed of the mobile user device, the speed of the mobile user device determined using a speedometer mounted in or on the mobile user device the direction of travel of the mobile user device, wherein the direction of travel of the mobile user device is determined using an electronic compass mounted in or on the mobile user device, and the location of the mobile user device relative to a location of the base station, wherein the location of the mobile user device is determined using a satellite-based navigation system;

receive a first message, from the mobile user device, at the channel frequency; and

transmit a second message, to the mobile user device, at the channel frequency minus two times the frequency shift.

12. The base station of claim 11 , further configured to:

receive a third message, from the mobile user device, specifying the location, the speed, and the direction of travel of the mobile user device.

13. The base station of claim 11 , further configured to receive, from the mobile user device, a fourth message specifying the frequency shift.

14. The base station of claim 13 , wherein the channel frequency is related to one or more subcarriers in which the mobile user device has permission to transmit the fourth message.

15. A method for a first mobile user device to communicate with a second mobile user device, the method comprising:

determining, by the first mobile user device, a sidelink channel frequency allocated for wireless communication between user devices;

determining, by the first mobile user device, a location, a speed, and a direction of travel of the first mobile user device, the location of the first mobile user device determined using a satellite-based navigation system, the speed of the first mobile user device determined using a speedometer mounted in or on the mobile user device, and the direction of travel of the first mobile user device determined using an electronic compass mounted in or on the mobile user device;

receiving, by the first mobile user device, from the second user device, a message specifying a location, a speed, and a direction of travel of the second mobile user device;

calculating, by the first mobile user device, based at least in part on the location, speed, and direction of travel of the second mobile user device, a frequency shift proportional to the sidelink channel frequency.

16. The method of claim 15 , further comprising:

transmitting, by the first mobile user device, to the second mobile user device, a first message at the channel frequency; and

receiving, by the first mobile user device, from the second mobile user device, a second message at the sidelink channel frequency plus the frequency shift.

17. The method of claim 15 , further comprising:

transmitting, by the first mobile user device, to the second mobile user device, a first message at the channel frequency minus the frequency shift; and

receiving, by the first mobile user device, from the second mobile user device, a second message at the sidelink channel frequency.

18. The method of claim 15 , wherein the message comprises:

an interval of no transmission or of unmodulated carrier signal;

a demodulation reference exhibiting a maximum amplitude level, a minimum amplitude level, a maximum phase level, and a minimum phase level of a modulation scheme; and

an error-check field configured to reveal message faults.