Doppler effect compensation for radio transmission

Abstract

The goal of the invention is to keep the delay of a communication signal between a moving vehicle (mobile body) and a fixed base station constant. This is achieved by a Doppler compensation method for data to be transmitted within frames via radio transmission between a mobile body and some base station, both mobile body and base station comprise respectively a transceiver connected to an antenna for the radio transmission. The method comprises the step of determining the Doppler effect acting on the frames when transmitted as a signal through that radio transmission for a given speed and direction of motion of the mobile body with respect to the base station. It is then followed by the step to apply by the transceiver some sampling procedure comprising an allocation of different time delays to the signal, the different time delays being chosen following a law adapted to compensate the determined Doppler effect.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention will now be explained further with the reference to the attached drawings in which:

FIG. 1 is a schematic view of the principle according to the present invention;

FIG. 2 is a schematic view of an embodiment according to the present invention;

FIG. 3 is a schematic view of an alternative embodiment according to the present invention.

Claims

1. A Doppler compensation method for data to be transmitted within frames via radio transmission between a mobile body and a base station, both mobile body and base station comprise respectively a transceiver connected to an antenna for the radio transmission, the method comprises the following steps of: Determining the Doppler effect acting on the frames when transmitted as a signal through that radio transmission for a given speed and direction of motion of the mobile body with respect to the base station;The method being further wherein the step ofApplying by the transceiver some sampling procedure by allocating different time delays to the signal, the different time delays being chosen following a law adapted to compensate the determined Doppler effect.

2. The method according to claim 1 wherein the sampling procedure is performed at reception of a signal from the radio transmission before multiplexing the then delayed samples to regenerate the frames received from that radio transmission for a Doppler compensation at reception side.

3. The method according to claim 1 wherein the sampling procedure is performed after multiplexing a generated frame before transmission of the signal via the radio transmission for a Doppler compensation at transmission side.

4. The method according to claim 1 wherein the sampling procedure is achieved by transmitting the signal through a conducting path with along the path different outputs, the samples being tapped at a respective output according to the time delay to be allocated to.

5. The method according to claim 1 wherein the sampling procedure is achieved by transmitting the signal through conducting paths being delay lines with different propagation time property.

6. The method according to claim 1 wherein the sampling procedure is achieved by using a First In First Out (FIFO) buffer such that the signal buffered in the FIFO at a writing rate Rw different then the reading rate Rr at which the samples are read from the FIFO, the ratio between both rates Rr and Rw following the law adapted to compensate the determined Doppler effect.

7. The method according to claim 1 wherein a new determination of the Doppler effect is performed at regular time interval.

8. A radio frequency device comprising a transceiver connected to an antenna, the radio frequency device being comprises further a decision unit analyzing the Doppler effect acting on frames when transmitted as a signal through a radio transmission between a mobile body and a base station, the mobile body moving at a given speed and direction with respect to the base station while the decision unit controls a sampling unit from the transceiver such that different time delays is allocated by the sampling unit to the signal, the different time delays being chosen following a law adapted to compensate the determined Doppler effect.

9. The radio frequency device according to claim 8 wherein it is used for a Doppler compensation at reception side by applying the sampling unit on the signal received from the radio transmission, the signal being delayed accordingly by being transmitted through a time delay unit before being multiplexed to regenerate the frames received from that radio transmission.

10. The radio frequency device according to claim 8 wherein it is used for a Doppler compensation at transmission side by applying the sampling unit on already generated frames, the obtained samples being delayed accordingly by being transmitted through a time delay unit to generate the signal to be transmitted via the radio transmission.

11. The radio frequency device according to claim 9 wherein the time delay unit comprises a conducting path with along the path different outputs at which are taped the samples, the different paths corresponds to the different time delay to be allocate to the signal.

12. The radio frequency device according to claim wherein the time delay unit comprises conducting paths being delay lines with different propagation time property.

13. The radio frequency device according to claim 9 wherein the delay unit is made of a First In First Out [FIFO] buffer such that it is written in the FIFO at a writing rate Rw different then the reading rate Rr at which it is read from the FIFO, the ratio between both rates Rr and Rw being defined accordingly to compensate the determined Doppler effect.

14. A base station to be in connection via radio transmission with a mobile body moving at some given speed and direction with respect to the base station while the base station comprises a radio frequency device according to claim 8.

15. A mobile body to be in connection with a base station via radio transmission and moving at some given speed and direction with respect to the base station while the mobile body comprises a radio frequency device according to claim 8.