# US 9,038,916 B2 · Smart card with reconfigurable receiver

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- Number: US 9,038,916 B2
- Document ID: US9038916B2
- Status: Granted
- Kind: B2
- Application number: 13/252,999
- Filed: 2011-10-04
- Published: 2012-04-05
- Granted: 2015-05-26
- Earliest claimed: 2010-10-05
- Assignees: NXP B.V.
- Applicants: Ghiath Al-Kadi; Massimo Ciacci; Remco Cornelis Herman van de Beek
- Inventors: Ghiath Al-Kadi; Massimo Ciacci; Remco Cornelis Herman van de Beek
- Web page: https://patentgrep.com/patent/US9038916B2

## CPC

- G06K 19/0723: {the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs}
- G06K 19/07: with integrated circuit chips
- H04L 1/0053: {specially adapted for power saving}
- H04L 1/0075: {Transmission of coding parameters to receiver (H04L1/0023 takes precedence)}
- H04L 1/20: using signal quality detector
- H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
- Y02D 30/70: in wireless communication networks
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

The invention proposes a smart card which comprises a digital signal processing receiver that can automatically identify the type of a smart card reader based on the error vector magnitude of signals received from the reader. The digital signal processing receiver is able to reconfigure itself at runtime in order to optimally minimize its power consumption in dependence on the type of reader it is communicating with. Furthermore, the invention proposes a new preamble structure that comprises a basic part and an optional additional part.

## Claims

### Claim 1

A smart card for communicating with an NFC reader unit,
the smart card comprising a digital signal processing receiver,
characterized in that the digital signal processing receiver is arranged to determine the quality of a signal received from the NFC reader unit by determining the error vector magnitude of said signal
wherein the digital signal processing receiver is further arranged to reconfigure itself by shutting down power-hungry parts of itself in dependence on the quality of said signal, in order to minimize its power consumption, wherein the digital signal processing receiver comprises a power management unit configured to shut down an equalizer of the digital signal processing receiver if the quality of said signal is above a given threshold;
wherein the digital signal processing receiver is further arranged to determine whether the NFC reader unit transmits:
either a first preamble only, said first preamble comprising a basic training sequence for calibrating one or more signal parameters,
or both said first preamble and a second preamble, said second preamble comprising an additional training sequence for calibrating said signal parameters,
wherein the digital signal processing receiver concludes that both said first preamble and said second preamble is transmitted if the error vector magnitude is above a predetermined threshold;
wherein the signal parameters comprise one or more of the following parameters: DC offset, gain misadjustment, and timing offset.

### Claim 2 (depends on 1)

A smart card as claimed in claim 1,
wherein the second preamble is embedded in the payload of a transmitted frame.

### Claim 3 (depends on 1)

A smart card as claimed in claim 1,
wherein the additional training sequence comprises a white training sequence.

### Claim 4 (depends on 1)

A system comprising a smart card as claimed in claim 1 and an NFC reader unit adapted to communicate with said smart card.