Parallel RFID system using CDMA

• US 20070222560A1
• Filed: 03/23/2006
• Published: 09/27/2007
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Posamentier, Joshua
• Granted Patent: US 8,044,773 B2
• Time in Patent Office: Days
• US Class Current: 340/10.200
• 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 7/10019 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

Various embodiments of the invention may use code division multiple access (CDMA) technology in communications from radio frequency identification (RFID) tags to RFID readers, so that multiple RFID tags may respond to the same RFID reader at the same time on the same frequency and still be reliably decoded by the RFID reader. In some embodiments, orthogonal CDMA PN sequences for the RFID tags to use in creating their responses may first be transmitted to those RFID tags, possibly using a non-CDMA technique.

Claims

1. An apparatus, comprising

a radio frequency identification (RFID) tag circuit to encode data for wireless transmission using a code division multiple access (CDMA) technique.

2. The apparatus of claim 1, wherein the RFID tag circuit is to:

receive and store a CDMA pseudo-noise (PN) sequence; and

use the CDMA PN sequence to encode the data to transmit a response to an RFID reader device.

3. The apparatus of claim 2, wherein the RFID tag is to synchronize the response with timing based on a received signal.

4. The apparatus of claim 2, further comprising a dipole antenna coupled to the RFID tag circuit.

5. The apparatus of claim 1, wherein the transmission is to be a modulated reflection of a received signal

6. The apparatus of claim 5, wherein the received signal is not to be encoded using the CDMA technique.

7. An apparatus, comprising:

a radio frequency identification (RFID) reader device to transmit a first code division multiple access (CDMA) pseudo-noise (PN) sequence to a first RFID tag for the first RFID tag to use in transmitting a first response to the RFID reader device.

8. The apparatus of claim 7, wherein the RFID reader device is further to transmit a second CDMA PN sequence to a second RFID tag for the second RFID tag to use in transmitting a second response to the RFID reader device.

9. The apparatus of claim 8, wherein the RFID reader device is further to:

receive the first and second responses, with the first and second responses at least partially overlapping in time; and

decode, using a CDMA technique, the first and second responses into first data from the first RFID tag and second data from the second RFID tag.

10. The apparatus of claim 8, wherein the transmissions to the first and second RFID tags are not to use the CDMA technique.

11. The apparatus of claim 8, further including a dipole antenna coupled to the RFID reader device.

12. A method, comprising:

using, in a radio frequency indentification (RFID) tag, a code division multiple access (CDMA) pseudo-noise (PN) sequence to encode data for transmission; and

transmitting the transmission to an RFID reader.

13. The method of claim 12, further comprising receiving, by the RFID tag, a wireless signal modulated to contain the CDMA PN sequence prior to said using, wherein the wireless signal is not encoded using a CDMA technique.

14. The method of claim 12, further comprising synchronizing the transmission with timing derived from a received signal.

15. A method, comprising:

receiving a first transmission from a first radio frequency identification (RFID) tag and a second transmission from a second radio frequency identification tag, the second transmission at least partially overlapping the first transmission in time; and

using a code division multiple access (CDMA) technique to decode the first and second transmissions.

16. The method of claim 15, further comprising:

transmitting, prior to said receiving, a first CDMA pseudo-noise (PN) sequence to the first RFID tag to be used to encode data for the first transmission; and

transmitting, prior to said receiving, a second CDMA PN sequence to the second RFID tag to be used to encode data for the second transmission.

17. The method of claim 15, wherein said transmitting the first and second CDMA PN sequences does not use CDMA techniques.

18. An article comprising

a tangible machine-readable medium that contains instructions, which when executed by one or more processors result in performing operations comprising:

receiving a first transmission from a first radio frequency identification (RFID) tag and a second transmission from a second radio frequency identification tag; and

using a code division multiple access (CDMA) technique to decode the first and second transmissions.

19. The article of claim 18, wherein the operations further comprise:

transmitting, prior to said receiving, a first CDMA pseudo-noise (PN) sequence to the first RFID tag to be used to encode data for the first transmission; and

transmitting, prior to said receiving, a second CDMA PN sequence to the second RFID tag to be used to encode data for the second transmission.

20. The article of claim 18, wherein the operations of receiving the first and second transmissions comprises receiving the first and second transmissions at least partly at a same time.