Method and apparatus for effecting a wireless exchange of data between a stationary station and moving objects

• US 5,757,285 A
• Filed: 12/11/1996
• Issued: 05/26/1998
• Est. Priority Date: 06/01/1993
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Robert Bosch GmbH
• Inventors: Dobias, Felix, Grabow, Wilhelm
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): LIEU, JULIE BICHNGOC
• Application Number:
  US08/764,673
• Time in Patent Office: 531 Days
• Field of Search: 340/928, 340/905, 340/825.5, 235/384, 235/385, 364/436, 364/438, 455/517, 455/507, 342/380, 342/383, 342/373, 342/457
• US Class Current: 340/928
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

A method for effecting a wireless exchange of data between a stationary station and transmitter/receivers on board objects, particularly vehicles moving relative to the stationary station. The reception profiles of an antenna array having a plurality of receiving antennas is directed electronically onto an object. The transmitter/receivers on the object transmit, in response to the received signal, an answer signal having the same carrier frequency as the signal received and having a level which is proportional to the level of the signal received. In the antenna array, a transmitting antenna is associated with each receiving antenna, and the transmitting antenna sends out signals having a transmission profile which corresponds to the reception profile of the receiving antenna. The damping factors of transmission profile and reception profile are thereby multiplied by each so that two relatively simple circuits are necessary in order to achieve a desired high side-lobe damping.

Claims

1. A method for providing a wireless exchange of data between a stationary station and at least one transmitter/receiver disposed on at least one respective object moving relative to the stationary station, the method comprising the steps of:

(a) setting a transmission profile for each of a plurality of transmitting antennas at the stationary station determined by a vectorial weighing process using a beam-forming network and controlled by a processor;

(b) setting a reception profile, under the control of the processor, for each of a plurality of receiving antennas at the stationary station corresponding to a respective one of the transmitting antennas, the reception profile for each of the plurality of receiving antennas corresponding to the transmission profile of the respective one of the plurality of transmitting antennas;

(c) transmitting, from each of the plurality of transmitting antennas at the stationary station, an original signal to a respective one of the at least one transmitter/receiver using the transmission profile, the transmission profile creating a damping effect on the original signal, producing a damped original signal;

(d) transmitting, in response to the damped original signal, a reply signal from the at least one transmitter/receiver, the reply signal having a carrier frequency and level which are equal to a carrier frequency and level, respectively, of the damped original signal; and

(e) receiving the reply signal by at least one of the plurality of receiving antennas at the stationary station using the reception profile, creating a damping effect on the reply signal;

wherein the damping effect on the original signal and the damping effect on the reply signal are multiplicative in effect.

2. The method according to claim 1, wherein step (a) includes the steps of transmitting a first original signal from one of the plurality of transmitters at a first carrier frequency, and transmitting a second original signal from an adjacent one of the plurality of transmitters at a second carrier frequency, and wherein the method further comprises the step of discarding any reply signal received at one of the plurality of receiving antennas corresponding to the one of the plurality of transmitting antennas when said any reply signal is not received at the first carrier frequency.

3. The method according to claim 2, wherein the plurality of transmitting antennas includes at least four transmitting antennas, and each of the at least four transmitting antennas transmits at a different carrier frequency.

4. A system for providing a wireless exchange of data, the system comprising:

(a) a stationary station including at least one processor and a plurality of antenna arrays, each of the plurality of antenna arrays including a plurality of transmitting antennas and a plurality of receiving antennas, each of the plurality of transmitting antennas corresponding to a respective one of the plurality of receiving antennas, each of the plurality of transmitting and receiving antennas including a beam-forming network, the at least one processor setting a transmission profile of each of the plurality of transmitting antennas corresponding to a reception profile of each of the plurality of receiving antennas, each of the plurality of transmitting antennas transmitting a signal using the transmission profile set by the at least one processor, the transmission profile creating a damping effect on the signal, producing a damped signal; and

(b) at least one transmitter/receiver located on at least one respective object moving relative to the stationary station, the at least one transmitter/receiver receiving the damped signal and transmitting, in response to the signal, a reply signal, the reply signal having a carrier frequency and level, respectively, of the damped signal, at least one of the plurality of receiving antennas receiving the reply signal using the reception profile, the reception profile creating a damping effect on the reply signal;

wherein the damping effect on the signal and the damping effect on the reply signal are multiplicative in effect.

5. The system according to claim 4, wherein each of the plurality of transmitting antennas is controlled by a respective processor of the at least one processor and is arranged adjacent to its respective one of the plurality of receiving antennas, the respective one of the plurality of receiving antennas also being controlled by the respective processor of the at least one processor.

6. The system according to claim 5, wherein a signal transmitted from one of the plurality of transmitters is at a first carrier frequency, and a signal transmitted from an adjacent one of the plurality of transmitters is at a second carrier frequency.

7. The system according to claim 5, wherein the at least one object includes a plurality of vehicles traveling in respective lanes of a road.