Method and device for transmission of data in an electronic shelf labeling system

• US 20040011868A1
• Filed: 08/19/2003
• Published: 01/22/2004
• Est. Priority Date: 10/31/2000
• Status: Active Grant

• Current Assignee: Pricer AB
• Original Assignee: Pricer AB
• Inventors: Backlund, Bjorn, Tjerneld, Fredrik
• Granted Patent: US 7,213,751 B2
• Time in Patent Office: Days
• US Class Current: 235/383
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2380/04 Electronic labels
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging

Abstract

A method for creating synchronized transmission of messages in a wireless electronic shelf labeling system comprising at least two transmitters, a plurality of receiving label-units and a central processing unit capable of issuing messages to be transmitted via said transmitters. Wherein a first step involves determining, for each transmitter, the signal delay between issuing of a message at the central processing unit and transmission of the message from the transmitter. Wherein a second step involves actively delaying, in response to said determined signal delay, transmission from the individual transmitters such that synchronized transmission from all transmitters is achieved. The present invention further relates to a wireless electronic shelf labeling system and a transmitter for such a system.

Claims

1. A method for creating synchronized transmission of messages in a wireless electronic shelf labeling system comprising at least two transmitters, a plurality of receiving label-units and a central processing unit capable of issuing messages to be transmitted via said transmitters, the method comprising

determining, for each transmitter, the signal delay between issuing of a message at the central processing unit and transmission of the message from the transmitter;

actively delaying, in response to said determined signal delay, transmission from the individual transmitters such that synchronized transmission from all transmitters is achieved.

2. Method according to claim 1 characterized in that the active delay of the transmission from the transmitters is performed by an active signal delay unit associated with each transmitter.

3. Method according to claim 1 or 2 characterized in that the step of determining the signal delay comprises setting the transmitters in a mirror-mode so that they automatically mirror all received pulses back to the central processing unit and measuring the time-diference between sending and receiving the same pulse.

4. Method according to any of the claims 1 to 3 characterized in that the active delay for each transmitter is set to the difference between the delay to that particular transmitter and a predefined maximum delay value.

5. Method according to any of the claims 1 to 3 characterized in that the active delay for each transmitter is set to the difference between the delay to that particular transmitter and the highest determined signal delay to any transmitter in the system.

6. A transmitter for a wireless electronic shelf labelling system, characterised in that it comprises an active signal delay unit that is arranged to delay transmission from said transmitter, and is adjustable in correspondence with an active signal delay parameter.

7. A transmitter for a wireless electronic shelf labelling system according to claim 6 characterised in that the active signal delay unit comprises a shift-register.

8. A wireless electronic shelf labelling system comprising at least two transmitters, a plurality of receiving label-units and a central processing unit capable of issuing messages to be transmitted via said transmitters, characterised in that it comprises one or more active signal delay units that are arranged to delay transmission from said transmitters, and adjustable in correspondence with an active signal delay parameter.

9. A wireless electronic shelf labelling system according to claim 8, characterised in that each active signal delay unit is arranged in a transmitter and arranged to delay transmission from said transmitter.

10. A wireless electronic shelf labelling system according to claim 8, characterised in that the active signal delay units are arranged at the central processing unit and arranged to delay issuing of messages their associated transmitters.

11. A wireless electronic shelf labelling system according to any of the claims 8 to 10, characterised in that the transmitters communicates with the central processing unit by means of distribution lines in the form of cables.

12. A wireless electronic shelf labelling system according to any of the claims 8 to 10, characterised in that the transmitters communicates with the central processing unit by means of wireless connections.