Rfid tag device, tag identification device and radio communication system

Abstract

An RFID tag device has a random number generator which generates a random number or a pseudo-random number, an identification information holding unit which holds identification information having a plurality of bits, a noise addition processing unit which generates noise-added identification information by conducting either of reversal from “0” of a bit decided based on the random number generated by the random number generator to “1” or reversal from “1” of the bit to “0”, among a plurality of bits included in the identification information, and a radio communication unit which transmits the noise-added identification information by radio.

1 . A communication method of using an RFID tag device, comprising:
 generating a random number or a pseudo-random number;   holding identification information having a plurality of bits;   generating noise-added identification information by conducting either of reversal from “0” of a bit decided based on the generated random number generator to “1” or reversal from “1” of the bit to “0”, among a plurality of bits included in the identification information; and   transmitting the noise-added identification information by radio.   
   
   
       2 . The method according to  claim 1 , further comprising:
 storing the generated random number in an temporary storage unit,   wherein the random number stored in the temporary storage unit is transmitted with the noise-added identification information by radio.   
   
   
       3 . The method according to  claim 1 , further comprising:
 measuring a time after transmitting the noise-added identification information,   wherein a subsequent noise-added identification information is transmitted when the measured time is a predetermined time or more.   
   
   
       4 . The method according to  claim 1 , further comprising:
 generating a noise relating to a noise included in the noise-added identification information,   wherein the generated noise is transmitted with the noise-added identification information by radio.   
   
   
       5 . A communication method of using an RFID tag device, comprising:
 holding a filter having a plurality of bits capable of probabilistically detecting whether or not a certain bit string is included in a group of bit strings;   generating a random number or a pseudo-random number;   generating a noise-added filter obtained by either of reversal from “0” of a bit decided based on the generated random number or reversal from “1” of a bit decided based on the generated random number among a plurality of bits included in the filter; and   transmitting the noise-added filter by radio.   
   
   
       6 . The method according to  claim 5 , wherein the held filter is generated by using the identification information having a plurality of bits and a Hash function. 
   
   
       7 . The method according to  claim 5 , wherein the held filter is a fixed bloom filter. 
   
   
       8 . The method according to  claim 5 , wherein the noise-added filter is obtained by reversing “0” of a bit decided based on the random number generated by the random number generator to “1”, among the plurality of bits included in the held filter. 
   
   
       9 . The method according to  claim 5 , further comprising: selecting any of a plurality of filters held,
 wherein the noise-added filter is generated corresponding to the selected filter.   
   
   
       10 . The method according to  claim 5 , further comprising:
 storing the generated random number in a temporary storage unit,   wherein the random number stored in the temporary storage unit is transmitted with the noise-added filter by radio.   
   
   
       11 . The method according to  claim 5 , further comprising:
 measuring a time after transmitting the noise-added filter,   wherein a subsequent noise-added filter is transmitted when the measured time is a predetermined time or more.   
   
   
       12 . The method according to  claim 5 , further comprising:
 generating a noise relating to a noise added to the noise-added filter,   wherein the noise generated by the noise generating is transmitted with the noise-added filter by radio.