Abstract: Data encoded in packets modulated onto a carrier wave is transmitted between a base station and a transponder. Each packet includes a header section that contains at least a reference symbol and that serves for adjusting one or more transmission parameters, and a further section such as a data section. The transponder transmits data back to the base station through modulation and backscattering of the carrier wave. During the transmission of the header section by the base station, the transponder transmits transponder operating information relating to the processing of data to be received and/or transmitted by the transponder, by corresponding modulation and backscattering of the carrier wave. In response to and dependent on the received transponder operating information, the base station adjusts at least one transmission parameter, whereby the highest data transmission rate within the capabilities of the particular transponder can be achieved.

Abstract: A method and system for data communication between a base station and at least one transponder via a high-frequency electromagnetic carrier signal onto which information packets are modulated. Each information packet has a header section, a middle section, and a trailer section. The header section can be provided in a forward link of a data communication between the base station and the transponders for controlling data communication. The header section is used in a return link of a data communication in order to transmit information from the transponder to the base station.

Abstract: A method and device for selecting one or more transponders, in particular backscatter-based transponders, from a plurality of transponders by a base station, which method is based on a slotted ALOHA method, in which the base station defines numbered time slots and a random number generated in a given transponder determines a time slot when the transponder transmits its transponder-specific identification to the base station.

Abstract: A method and apparatus for locating a transponder is provided. A carrier signal is transmitted by a base station and a transponder transmits a locating signal that is generated through phase modulation and backscattering of the carrier signal sent by the base station when the transponder is within a transmission range of the base station, whereby the transponder is located on the basis of the locating signal.

Abstract: A method for wireless data transmission between a base station and a transponder is provided, in which data are transmitted between the base station and the transponder in the form of data packets that include a header section with at least one symbol for setting one or more transmission parameters and include at least one additional section. The transponder monitors, during the data transmission, to determine whether a time period between two successive symbol delimiters transmitted by the base station exceeds a maximum time, and if the maximum value is exceeded, a receiver unit of the transponder is reset. The maximum time can be determined in the transponder on the basis of the at least one symbol in the header section.

Abstract: A method for recognizing time-variable functional states, e.g., in the course of a programming process, in RFID systems is disclosed, which includes at least one transponder or remote sensor and at least one base station, which transmits data and/or power to the transponder or sensor by a carrier signal. According to the invention, after a specified process state is attained at least one confirmation symbol is transmitted by the transponder or sensor to the base station. As a result, no unfavorable “worst case” scenario has to be provided for chronologically controlling time-variable processes because the base station is able to clearly recognize the beginning and end of the process, as well as the state thereof. RFID systems or remote sensor systems can thus be controlled more quickly and more reliably, resulting especially in reduced costs.

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.

Abstract: A method for communication between a base station and a plurality of transponders, whereby a group with at least two transponders is selected by the base station from among a plurality of transponders and a first transponder is selected from the group of transponders, whereby a session to exchange data is arranged with the first transponder, and whereby the session has a starting time and an ending time, and data are exchanged with the first transponder during the session and a second transponder of the group is selected by the base station during the session with the first transponder and a session is arranged with the second transponder.

Abstract: A method for selecting at least one transponder or a sensor in RFID or remote-sensor systems provided with a plurality of transponders or sensors (tags), in particular in systems provided with a plurality of reading devices, is disclosed. The inventive method includes the feature that in pre-selecting individual transponders or sensors by at least one reading device and, after the successful selection of at least one transponder or sensor, data, in particular for conforming the preselection, is asynchronously transmitted during at least one protocol section from the transponder or sensor to the reading device. The invention makes it possible to efficiently reduce the potentially disturbing control signals of the reading device(s), thereby improving the transmission characteristics of said systems.

Abstract: A method for transponder access control is disclosed, in which a first identification is stored in the transponder, which is transmitted to a reader unit upon appropriate request by the unit. At least one second identification and an identification selection criterion are stored in the transponder, during a request by the reader unit depending on the identification selection criterion either the first identification or the at least second identification is transmitted and, when the second identification is transmitted, access to the transponder, particularly to the first identification, is released by the transponder when the reader unit transmits a password assigned to the second identification to the transponder.

Abstract: A backscatter transponder for an HF communication system with modulated reradiation, is provided that includes an antenna for receiving high-frequency carrier signals, wherein the antenna has reflective characteristics, a control unit for providing transponder-specific parameters, and a modulator that can be driven by the control unit. The modulator altering the reflective characteristics of the antenna in accordance with at least one transponder-specific parameter.

Abstract: A method for transmitting data between a base station and at least one remote unit is provided. Conventional approaches to communication based on a predefined uniform transmission protocol do not function especially in open RFID systems with at least one base station and tags of a different (and variable) type and number, in which different customers are provided with one and the same tag solution. Primarily if several customers each wish to use a customer-specific solution, this can no longer be represented by a single uniform code. The method of the present invention makes it possible to introduce new, protocol-extending instruction sequences (protocol extensions) and to recognize these reliably as such, whereby these are not in conflict with the existing protocol.

Abstract: A method and apparatus for transmitting data in a radio frequency identification system, which includes a reader and at least one transponder, is provided. The reader transmits data sequences to the transponder including at least command data, associated check data, and a subsequent return link header data. Upon receiving unrecognized command data and/or unsupported parameter and address data the transponder notifies the reader of this condition. The notification takes place at times when the reader transmits end signals indicating an end of a data sequence, transmits an optional parameter and address data, or transmits the return link header data. Thus, communication between the reader and other transponders is not disrupted when a transponder cannot execute a command.

Abstract: A plurality of information symbols are transmitted by a carrier wave by assigning different modulation indices to the individual information symbols. Thereby the modulated carrier wave carries information not only by the digitally encoded (modulated) data words but also by the different modulation indices used for successive intervals that thus also represent information symbols. This increases the data rate of a wireless communication. When used in passive identification systems, for example transponders, the transmission of the superimposed clock information eliminates the need for the clock generation logic in the receiver. The reduced energy consumption enables the communication distance to be increased.

Abstract: A semiconductor structure, for improving rectifier efficiency in passive backscatter transponders or backscatter remote sensors for use in high-frequency electromagnetic fields, is provided. The semiconductor structure has a dielectric layer on whose upper side is arranged a first electrically conductive layer, and a second electrically conductive layer that is spaced apart from the first electrically conductive layer and is arranged essentially below the first electrically conductive layer and is at least partially embedded in the dielectric layer. The dielectric layer has its lower side arranged on a semiconductor substrate of a first conductivity type within which is formed a more highly doped first zone of the first conductivity type which surrounds an even more highly doped second zone of the first conductivity type connected to a reference voltage. Whereby, the first zone can be arranged essentially completely under the first and second electrically conductive layers.

Abstract: A method for wireless data transmission between a base station and one or more, in particular passive, transponders is provided, in which electromagnetic carrier waves are emitted by the base station. Data comprising successive characters are transmitted from a respective transponder to the base station by modulation and backscattering of the electromagnetic carrier waves, and a respective one of the characters is coded and transmitted by a respective transponder within a predefined time interval. Within at least one of the predefined time intervals, a safeguard character formed from the data to be transmitted is transmitted in addition to the character to be transmitted.

Abstract: A method and apparatus includes at least one transponder or sensor to transmit useful data in an asynchronous mode to at least one reader. Before the start of the useful data transmission, the reader transmits a return link header to the transponder or sensor, which contains at least one bit length reference symbol as a reference time to define the bit length in the return link.

Abstract: A storage circuit arrangement for a semi-passive or passive RFID transponder is provided. In prior-art circuit arrangements, storage capacitors are routinely discharged in an undefined fashion via leakage currents for a control mode of the transponder, so that the persistence times depend greatly on the ambient temperature and on existing manufacturing tolerances. It is proposed according to an embodiment to charge a first electrical storage device with a first reference voltage and then to discharge it again in a defined fashion during a time t via discharge device. Advantageously, in addition a storage mode of the first storage device to hold the control mode can be transmitted in a controlled fashion via a switching device to a second storage device with C2<<C1 to shorten a settle time and to accelerate the anticollision.

Abstract: A method and device for wireless data transmission between a base station and one or more transponders, in which electromagnetic carrier waves are emitted by the base station and symbols are transmitted from a given transponder to the base station by modulation and backscattering of the electromagnetic carrier waves, wherein a change in a modulation state takes place synchronously with synchronization markers transmitted by the base station. A change in the modulation state is carried out by a transponder with a specifiable time delay that is relative to the synchronization markers.

Abstract: A transponder is provided having at least one memory area, whereby the memory area is assigned an access password, the access password is assigned at least one attribute bit, and the length and/or structure of the access password can be set by the attribute bit. The invention relates further to a method for access to at least one access password-protected memory subarea of the transponder and to an RFID system comprising a transponder.