Method and apparatus for communication in ultra-wide bandwidth RFID systems

• US 8,952,789 B2
• Filed: 02/25/2009
• Issued: 02/10/2015
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Alma Mater Studiorum Universita' Di Bologna (Repubblica Italiana)
• Original Assignee: Alma Mater Studiorum Universita' Di Bologna (Repubblica Italiana)
• Inventors: Dardari, Davide
• Primary Examiner(s): Mehmood, Jennifer
• Assistant Examiner(s): MORTELL, JOHN F
• Application Number:
  US12/920,031
• Publication Number:
  US 20110050399A1
• Time in Patent Office: 2,176 Days
• Field of Search: 340/10.4
• US Class Current: 340/10.3
• CPC Class Codes: G01S 13/02 Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
• CPC Class Codes: G01S 13/756 using a signal generator for modifying the reflectivity of the reflector G01S13/758 takes precedence
• CPC Class Codes: 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
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10306 ultra wide band
• CPC Class Codes: H04B 1/719 Interference-related aspects

Abstract

A method for communication in ultra-wide bandwidth RFID systems comprising generating through a transceiver device an interrogated signal, composed of at least a sequence of equally time spaced pulses with period (T3), transmitting said signal to at least one RFID identification device which generates a response signal and transmits it back to said transceiver device, said method further comprising coding said interrogation signal according to a numerical coding sequence, generating said response signal by varying, in each period (T3) of said pulse sequence of the interrogation signal, the polarity of pulses using said numerical coding sequence. An apparatus for communication in ultra-wide bandwidth RFID systems comprising a transceiver device (1,101) and a RFID identification device (11), suitable for communicating each other, said RFID identification device (11) comprises a backscatter modulator (12) suitable for modulating a signal reflected by an antenna (18) of the identification device RFID.

Claims

1. A method for the communication in ultra-wide bandwidth RFID systems, comprising the steps of generating through a transceiver device an interrogation ultra-wide bandwidth signal, said interrogation signal comprising a series of sequences of pulses with a period, each sequence of pulses being composed of a plurality of equally time spaced pulses, transmitting said interrogation signal to at least one RFID identification device, processing said interrogation signal according to the information stored in said RFID device and transmitting it back to the transceiver device as a response signal, receiving said response signal through said transceiver device and further processing said response signal to detect said information included in said response signal, wherein the method further comprises the steps of

coding said interrogation signal during said generating in said transceiver device according to a numerical coding sequence that determines the polarity of each pulse of each sequence of pulses;

generating, in said RFID identification device, said response signal by varying, in each sequence of pulses of said series of sequence of pulses of the interrogation signal, the polarity of the pulses using said numerical coding sequence, so that all reflected pulses in a same sequence of pulses have the same polarity, the polarity of the pulses in a same sequence of pulses depending on the information bit to be transmitted; and

summing together the pulses in each sequence of the response signal.

3. The method according to claim 1, wherein said numerical sequence is a binary c_nε

{−

1,1}, or ternary c_nε

{−

1,0,1} numerical sequence.

4. The method according to claim 3, wherein said numerical sequence is a zero or quasi-zero sum numerical sequence.

5. The method according to claim 4, wherein in each period of said numerical sequence the number of positive units is equal to the number of negative units.

6. The method according to claim 4, wherein in each period of said numerical sequence the number of positive units differs from the number of negative units in one unit.

7. The method according to claim 1, wherein the duration of each pulse in each sequence of pulses is less than one nanosecond.

8. The method according to claim 1, wherein a time interval between two successive pulses in each sequence of pulses is not less than 50 nanoseconds.

9. The method according to claim 1, wherein the time interval between two successive pulses in each sequence of pulses is greater than 100 nanoseconds.

2. A method for the communication in ultra-wide bandwidth RFID systems, comprising the steps of generating through a transceiver device an interrogation ultra-wide bandwidth signal, said interrogation signal comprising a series of sequences of pulses with a period, each sequence of pulses being composed of a plurality of equally time spaced pulses, transmitting said interrogation signal to at least one RFID identification device, processing said interrogation signal according to the information stored in said RFID device and transmitting it back to the transceiver device as a response signal, receiving said response signal through said transceiver device and further processing said signal to detect said information included in said response signal, wherein the method further comprises the steps of

generating said sequence of pulses so that all pulses of a same sequence of pulses have the same polarity;

generating, in said RFID identification device, said response signal by coding said interrogation signal according to a numerical coding sequence and to the information stored in said RFID device that determines the polarity of each pulse of each sequence of pulses;

decoding, in said transceiver device, said response signal by modifying, in each sequence of pulses of said series of sequences of pulses of the response signal, the polarity of pulses using said numerical coding sequence, so that all pulses in a same sequence of pulses have the same polarity; and

summing together the pulses in each sequence of pulses of the response signal after said decoding.

18. The method according to claim 2, wherein said numerical sequence is a binary c_nε

{−

1,1}, or ternary c_nε

{−

1,0,1} numerical sequence.

19. The method according to claim 2, wherein the duration of each pulse in said sequence of pulses is less than one nanosecond.

20. The method according to claim 2, wherein a time interval between two successive pulses of said sequence of pulses is not less than 50 nanoseconds.

21. The method according to claim 2, wherein a time interval between two successive pulses of said sequence of pulses is greater than 100 nanoseconds.

10. An apparatus for the communication in ultra-wide bandwidth RFID systems, comprising a transceiver device and a RFID identification device suitable for communicating with each other, wherein said transceiver device comprises a transmitting portion and a receiving portion, said transmitting portion comprising a first numerical sequence generator for generating an interrogation signal comprising a series of sequences of pulses with a period, each sequence of pulses being composed of a plurality of equally time spaced pulses, and wherein said RFID identification device comprises a backscatter modulator suitable for modulating a signal generated by said transceiver device and reflected back by an antenna of the RFID identification device, said backscatter modulator comprising a first switch placed in parallel with the antenna and a second switch, in parallel with the antenna and in series with a load impedance, said backscatter modulator further comprising a delay line placed in series with the antenna and comprising a third switch and a fourth switch, both said third switch and said fourth switch being placed in series with the antenna.

11. The apparatus according to claim 10, wherein said first numerical sequence generator is operationally associated with a pulse generator.

12. The apparatus according to claim 10, wherein said first numerical sequence generator is associated with a multiplier device suitable for multiplying the signal received by said receiving portion by said numerical sequence.

13. The apparatus according to claim 11, wherein said first numerical sequence generator generates a binary c_nε

{−

1,1}, or ternary c_nε

{−

1,0,1} numerical sequence.

14. The apparatus according to claim 11, wherein said receiving portion comprises a matched filter, a sampler device, an accumulation unit, a threshold detector, an antenna and a switch to alternatively connect said antenna to said transmitting portion and said receiving portion.

15. The apparatus according to claim 10, wherein said RFID identification device comprises a second numerical sequence generator, a control unit, a synchronization unit, and a memory unit.

16. The apparatus according to claim 15, wherein said second numerical sequence generator generates a numerical sequence identical to the numerical sequence generated by said first numerical sequence generator.

17. The apparatus according to claim 15, wherein said RFID identification device further comprises a power unit.

22. The apparatus according to claim 12, wherein said first numerical sequence generator generates a binary c_nε

{−

1,1}, or ternary c_nε

{−

1,0,1} numerical sequence.