Data transmission method and apparatus in RFID and remote sensor systems

Abstract

A method and apparatus is provided for data transmission in RFID and remote sensor systems with at least one reader and a plurality of transponders or remote sensors being located in an electromagnetic field of the reader, in which a multipart return link header containing transmission parameters for the return link, such as timing or modulation references, is transmitted at the beginning of a return link transmission of useful data from a transponder or sensor to a reader. A relative time duration of individual subsymbols of the return link header is modified to select a data transfer mode from among a number of different data transfer modes. A combination of different return link transmission mechanisms is thereby possible, whereby these are mutually compatible and moreover are simple to realize in terms of circuitry and control engineering.

Description

[0001] This nonprovisional application claims priority under 35 U.S.C. § 119(a) on German Patent Application No. DE102004014562.8-35, which was filed in Germany on March 25, 2004, and which is herein incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method and apparatus for data transmission in RFID and remote sensor systems including at least one reader and one or more transponders or remote sensors that are located in an electromagnetic field of the reader, in which a multipart return link header containing transmission parameters for the return link, such as modulation references, is transmitted at the beginning of a return link transmission of useful data from a transponder or sensor to a reader. [0004] 2. Description of the Background Art [0005] Automatic identification methods, also called auto-ID, have been widely used in recent years in many service sectors, in acquisition and distribution logist...

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Benefits of technology

[0017] It is therefore an object of the present invention to provide a method and apparatus so that a combination of different link mechanisms is possible, whereby these are to be mutually compatible and moreover simple to realize in terms of circuitry and control engineering, which is particularly important with respect to transponders or sensors to be able to operate at a correspondingly low cost in chip manufacture and installation.

[0019] Simple transfer of time information within a data structure present by default in this manner enables pre-selection of the transfer mode that is to be used, whereby the mentioned time information is not supplied by the carrier but by a modulation of the carrier, which leads to a notch signal. This in turn is then simple to detect. Only the transmission of a narrow band carrier is necessary to accomplish this on the part of the reader (base station). This in turn leads to a limitation of the reflection / multipath propagation effects in the near range (associated with a positive effect on SNR values in asynchronous transmission; see above) and permits a simple evaluation of the signals received from the transponder. This last property in turn has economic effects on the technical realization of the readers that are used.

Problems solved by technology

This in turn leads to a limitation of the reflection / multipath propagation effects in the near range (associated with a positive effect on SNR values in asynchronous transmission; see above) and permits a simple evaluation of the signals received from the transponder.

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