WO2008047338A1

WO2008047338A1 - Multi-function contactless data transaction transponder

Info

Publication number: WO2008047338A1
Application number: PCT/IL2006/001210
Authority: WO
Inventors: Ronnie Gilboa; Oded Bashan; Nehemya Itay; Moshe Aduk
Original assignee: On Track Innovations Ltd
Current assignee: On Track Innovations Ltd
Priority date: 2006-10-19
Filing date: 2006-10-19
Publication date: 2008-04-24
Anticipated expiration: 2009-04-19

Abstract

A multi-function contactless data transaction transponder having at least two contactless data transaction chips commonly coupled to the same coil antenna. The contactless data transaction chips are self-discriminating so that when the data transaction transponder enters an interrogation field communication with only one of the data transaction chips is maintained. The required self-discrimination may be achieved based on mutual relative sensitivities of the chips or on differences between protocols employed thereby or by use of an anti-collision mechanism or by suitable combinations of these factors.

Description

Multi-function contactless data transaction transponder

FIELD OF THE INVENTION

This invention relates to contactless smart cards.

BACKGROUND OF THE INVENTION

Smart cards having dual communication, modes are well known. For example, our earlier US Patent No. 6,045,043 discloses a data transaction device having contact and contactless modes of operation, wherein a semiconductor device operates in contact and contactless modes in accordance with a respective contact or contactless data communications protocol. A contact field includes contacts fixedly connected to the semiconductor device for allowing data transmission between the contacts and the semiconductor device in accordance with the contact data communications protocol, whilst a coil antenna allows contactless data transmission between the coil antenna and the semiconductor device, in accordance with the contactless data communications protocol. An antenna interface coupled to the coil antenna, to the semiconductor device and to at least some of the contacts in the contact field is responsive to an electromagnetic field across the coil antenna for effecting contactless data transmission.

Likewise, our earlier US Patent No. 6,161,762 discloses a data transaction device having a contactless mode of operation and comprising an antenna coil coupled to a processing unit via an antenna interface for allowing contactless data transmission between the data transaction device and a remote transceiver. The antenna interface may be customized for different applications and the data transaction device also includes a contact field thus allowing for either contact or contactless communication. These prior art smart cards provide dual communication modes but this is achieved by ensuring that one communication, mode is contactless while the other employs a set of contacts, typically complying with the ISO 7816 standard.

When contactless smart cards are used for different applications that operate in accordance with different protocols, this currently requires that separate smart cards be provided, each associated with a respective application and adapted to operate in accordance with a respective protocol. Thus, for example, one smart card may be adapted for use as a travel pass, while another may be adapted for use as an electronic purse. This means that when a user makes use of multiple contactless applications, he must currently carry multiple smart cards, which is inconvenient. It would therefore be desirable to allow a single smart card having dual processors to allow contactless operation for different applications and particularly those operating in accordance with different protocols.

The concept of multi-application transponders is known per se. For example, EP1688867 discloses the dual universal integrated circuit card (UICC) system for a portable device that includes a cellular phone or a personal digital assistance. The system comprises a slaver integrated circuit (IC) card having a first integrated circuit. A substrate is carrying for a master integrated circuit card having a second integrated circuit and a contact interface coupled to both integrated circuits. An antenna may be coupled to the second integrated circuit for transmitting information. In such a card, more than one IC is provided as distinct from the above-mentioned patents where only a single IC is provided, although it appears that the multiple ICs are not -mounted on a single card. Moreover, only a single antenna is provided and is coupled to the master integrated circuit. The slaver integrated circuit is coupled to a contact interface the master integrated circuit. Thus, only a single IC effects contactless communication via the antenna.

US2006/056216 (Rhelimi) discloses a portable object of the smart card type comprising a main circuit for internal processing and storage of data. The main circuit comprises several integrated circuits, each requiring a different supply voltage employing a contact interface complying with ISO 7816. No suggestion is made to effect contactless communication using multiple integrated circuits and no antenna is shown or described. US2003/030568 (Lastinger et al.) discloses monitoring systems and protocols that are flexible in mode operation and format depending on the environment in which they are used. Such monitoring systems and protocols are able to change their utilization automatically, or by received instruction to do so. In a location detection system, a low frequency transmitter transmits location identification information, such as the transmitter ID, to a tag in the vicinity of the transmission. The tag relays the transmitter ID using a higher frequency transmission sent from the tag to the receiver. Communication protocols are disclosed that enable deciphering of multiple tag transmissions starting simultaneously. The RF tags disclosed by this reference operate in contactless mode by means of an antenna, although there is no suggestion to effect contactless communication using multiple integrated circuits. It should also be noted that 'multiple tag transmissions starting simultaneously' relates to simultaneous or overlapping transmissions from multiple tags and not from a single tag.

Nevertheless the reference is interesting for its description of protocol discrimination based on received signal strength, whereby a tag is able to distinguish the stronger signal and thus determine which protocol to employ. Alternative approaches to the selection of protocol are presented in paragraphs [0157] to [0162]. Moreover, as noted in paragraph [0098], the ability to broadcast and receive signals according to different protocols allows the use of a single tag for multiple functions. It would thus be desirable to provide a single contactless smart card with multiple processors, each being adapted to serve a different application. Such a requirement not only does not appear to have been addressed by the prior art, but woμld appeal" to be counter-intuitive owing to the interaction between the multiple processors for reasons that will now be explained. Contactless smart cards operate when brought into proximity with an interrogation field that typically has a frequency of 13.56 MHz. Different contactless smart card communications standards are known having different ranges of sensitivity. For example, contactless cards complying with ISO/IEC 14443 are known as proximity cards and have a range of up to 10cm, while cards complying with ISO/IEC 15693 are known as vicinity cards and have a range of up to 1 meter. In all cases, data in the transponder is sent to the reader by loading the coil antenna in the transponder in response to the data so as to modulate the interrogation field and allow a reader to demodulate the modulated signal so as to extract the data. - A -

In order to provide a single contactless smart card having multiple processors, the inventors first conceived the idea of mounting two or more processor chips each coupled to a respective coil on the same card in order to allow the desired contactless communication with each chip. Clearly, in order that each processor be able to respond to the same interrogation field, each of the multiple coil antennas in the card must be tuned to the same transmitter frequency. But in order to allow for the possibility that all of the processors can effect communication, they must also be able to respond to a signal received by their respective coil antenna. Thereafter, only one of the processors may be allowed to continue communicating depending on suitable selection criteria, which may be signal strength as taught by above-mentioned US2003/030568, or protocol matching or any other suitable criterion. This means that while only one of the processors may be dominant, the other processors cannot be dormant, at least not during an initial stage when the smart card is first brought into the interrogation field and a desired processor is selected, after which the unselected processors may indeed be switched to standby state.

This sequence of operation means that during the initial stage when the smart card is first brought into the interrogation field, not only will the required processor load its coil antenna but so, too, will the processors that are not required load their respective coil antennas and this will act to detune the coil antenna to which the required processor is connected. Such de-tuning not only reduces the sensitivity of the smart card, but may even militate against effective reception and modulation of the interrogation field and/or the modulated interrogation field being sensed by the reader. In an attempt to reduce such de-tuning, the inventors contemplated increasing the mutual separation between coils but this resulted in reduced performance and an inefficient usage of card land. The inventors therefore concluded that it would be preferable to eliminate the need for two or more coil antennas each to be connected to a respective module and thus to allow all the modules to be connected to a common coil antenna.

SUMMARY OF THE INVENTION

According to the invention there is provided a multi-function contactless data transaction transponder, comprising: a coil antenna; and at least two contactless data transaction chips commonly coupled to said coil antenna; said contactless data transaction chips being self-discriminating so that when the data transaction transponder enters an interrogation field, communication with only one of the data transaction chips is maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, an embodiment will now be described, by way of non-limiting example only, of a dual-function contactless data transaction transponder and with reference to the accompanying drawings, in which:

Fig. 1 is a schematic circuit diagram of a dual-function contactless data transaction transponder according to an embodiment the invention; and

Fig. 2 is a flow diagram summarizing methods for effecting self-discrimination among different modules in a contactless data transaction transponder according to different embodiments of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 is schematic circuit diagram of a dual-function contactless data transaction transponder 10 according to an embodiment the invention comprising a coil antenna 11 and first and second contactless data transaction modules 12 and 13, respectively, commonly coupled to the coil antenna 11. It should be noted that within the context of the description and the appended claims, a module generally refers to a chip in a module having additional components, so that a single module may include two or more chips all commonly connected to the same coil antenna. However, each chip may be mounted in a separate module and commonly connected to the same coil antenna. In this case, there will be as many modules as there are chips. Likewise, a hybrid arrangement may be employed whereby there are commonly connected to the same coil, two or more modules at least one of which embeds more than one chip. Thus, use of the term 'module' envisages any of these arrangements.

For ease of description, it will be assumed that the two modules operate according to different protocols. For example, the first module 12 may operate according to the ISO 14443 Type A contactless protocol while the second module 13 may operate according to the ISO 14443 Type B contactless protocol. The main differences between these types concern modulation methods, coding schemes and protocol initialization procedures. Thus, the ISO/IEC 14443-3 Standard relating to proximity integrated circuit cards (PICC) includes a procedure for selecting one among several cards based on application criteria, i.e. the one it most likely has to transact with. In accordance with this procedure, a polling procedure is employed whereby in order to detect PICCs which enter its energizing field, a proximity coupling device (PCD) sends repeated Request commands and looks for an Answer to Request signal (ATQ). This process is referred to as "Polling". In Section 5.1.2 of the Standard, it is further noted that Type A and Type B commands and responses shall not mutually interfere. Polling Reset times are tabulated in Table 1 of the ISO/IEC 14443-3 Standard. Similar principles are applied to the modules 12 and 13, so as to allow only a single module to be polled. The same principles are employed by the present invention to select between different modules on the same card.

Part 2 of the ISO/IEC 14443-3 Standard defines the RF power and signal interface. Differences between Type A and Type B communication schemes include the modulation of the magnetic field used for coupling, the bit and byte coding format and the anti-collision method i.e., how the cards and readers respond when more than one card responds at the same time to a reader's request for data. Type A has an ASK of 100% Reader to Card modulation index, meaning that data is coded with short pauses in the transmission.- During these pauses no power is transmitted to the card. This dictates special requirements to the chip in the card. Type A uses Modified Miller bit coding. Type B, however, has an ASK of 10% Reader to Card modulation index, meaning that data is coded with only minor reduction of its normal amplitude, enabling both card and reader to maintain power throughout the communication process.

Anti-collision methods rely on a unique ID per module; however, depending on the communication type (A or B), the anti-collision method is different.

^■ Type A: Binary search method referring to the unique identifier (UID) of the module.

^■ Type B: Slotted Aloha method with special slot markers. Part 3 of the Standard defines the initialization and anti-collision protocols for Type A and Type B. The initialization and anti-collision scheme is designed to permit the construction of readers capable of communication with several cards of the same type, powered simultaneously. When applied to the present invention, both module types wait silently in the field for a polling command. A multi-protocol reader may poll one type, complete any transactions with the responding module, and then poll for the other type and transact with it. In a more likely scenario, each module of the multifunction card will respond to a single-protocol reader. According to the Standard it is not assumed that both types can be operative at the same time. However, so far as the invention is concerned, this is not a consideration. Indeed, all modules on the same card will inevitably be introduced into the reader's interrogation field at the same time and will thereby all be energized. But this does not mean that the chips in each module will be active since it is possible to configure the chips to be dormant until awakened by an activation signal. This may be done in a manner well-known in the art, such as described in US Patent No. 5,339,000 in the name of Easy Park and entitled "System for monitoring parked vehicles" , incorporated herein by reference and describing a portable parking tag that may be interrogated by a portable reading device carried by a parking official. The portable parking tag includes a data communications circuit powered by a battery or self-powered by a signal transmitted to the portable parking tag by the reading device and rectified within the portable parking tag in a manner well known in the art. When the portable parking tag is inactive, it may still be interrogated by the portable reading device and in this case the portable parking tag will likewise be self- powered in similar manner. This allows the parking tag to serve as a payment device for use in an automated parking system wherein a vehicle passing an entry barrier or exit receives an interrogation signal, which respectively awakens a dormant parking tag or shuts it down.

Fig. 2 is a flow diagram summarizing application of the above principles for effecting self-discrimination among two or more modules in the contactless data transaction transponder according to different embodiments of the invention. Thus, in the case of the two modules shown in Fig. 1, the modules 12 and 13 may be initially dormant and awakened by an energizing field transmitted by a card reader. Although both modules will thereby be wakened from their dormant state thus initiating the possibility of communication with both modules, only the one module that operates according to the reader's protocol will be able to effect communication with the reader. Thus, the use of different protocols serves to provide the desired self-discrimination whereby communication can be maintained with only a single chip. Any other modules will be partially shut down so as to put it into a dormant state wherein energy consumption is reduced while rendering the module amenable to activation during a subsequent session.

Each module has an associated internal capacitance denoted as 14 in Fig. 1. The coil antenna is tuned to the operating frequency using the combination of the associated internal capacitances, the coil internal capacitance 15 and an optional external capacitance 16.

Although the invention has been explained with regard to a multi-function card having chip modules that operate according to different protocols, the invention is also applicable for chip modules that operate according to the same protocol. In such case, on introducing the card into the energizing field, both modules will be energized and attempt to communicate. The resulting possible ambiguity is handled by an anti- collision protocol in known manner. Thus, in accordance with one known algorithm, the reader sends a message that requests the modules to generate a random number from 1 to n (n is defined by the reader). The reader then sends n. slots requests and each module answers in its preselected slot. If by chance the same random number was selected a collision will occur and the whole process will be initialized.

The invention thus provides a data transaction transponder having at least two self-discriminating contactless chip modules connected to a common coil antenna to operate when the data transaction transponder enters an interrogation field communication so that only one of the data transaction modules is or remains active. The required self-discrimination has been described with regard to the modules operating according to different protocols. However, the self-discrimination may be achieved by other means also. For example, when a hybrid data transaction transponder includes one or more 'proximity' modules conforming to ISO/IEC 14443 and a 'vicinity' module complying with ISO/IEC 15693, the 'vicinity' module will respond to an interrogation field from a range of up to 1 meter while the remaining data transaction modules, having a range of no more than 10cm, remain inactive. So in such case, self- discrimination may be based on the respective sensitivities of at least modules.

Likewise, self-discrimination may be based on combinations of different properties. For example, in the case of the above-mentioned hybrid data transaction transponder, if the reader does not operate in accordance with ISO/IEC 15693, then the high-sensitivity 'vicinity' module will be energized but will not send any data, and will stay in its initial dormant state. The data transaction transponder may now be brought close to the reader so that when the reader is in range of a low-sensitivity 'proximity' module operating according to the same protocol of the reader, the low-sensitivity 'proximity' module will awaken from its formerly dormant state and initiate communication.

Claims

CLAIMS:

1. A multi-function contactless data transaction transponder, comprising: a coil antenna; and at least two contactless data transaction chips commonly coupled to said coil antenna; said contactless data transaction chips being self-discriminating so that when the data transaction transponder enters an interrogation field, communication with only one of the data transaction chips is maintained.

2. The multi-function contactless data transaction transponder according to claim I₃ wherein the at least two data transaction chips have relatively high and low sensitivities, respectively, so that one of the data transaction chips responds to the interrogation field while all other of the data transaction chips remain inactive.

3. The multi-function contactless data transaction transponder according to claim 1 or 2, wherein the at least two contactless data transaction chips operate according to different respective contactless communication protocols.

4. The multi-function contactless data transaction transponder according to any one of claims 1 to 3, wherein the at least two contactless data transaction chips are adapted to operate according to an anti-collision protocol.