RFID system and method including tag ID compression

A method of compressing IDs of tags in an RFID system including a reader and a plurality of tags, different tags having different IDs, the IDs having a plurality of bits, the method comprising:

• (a) issuing from a reader a number n of sequential reads;
• (b) respective tags counting the reads and responding if bit n of their ID has a first value;
• (c) recording with the reader, bit locations at which a response was obtained;
• (d) issuing from the reader a number m of sequential reads;
• (e) respective tags counting the reads and responding if bit m of their ID has a second value different from the first value;
• (f) recording, with the reader, bit locations at which a response was obtained;
• (g) determining, with the reader, bit locations at which a response was received for both (c) and (f);
• and
• (h) sending a command from the reader to the tags to modify their IDs by shifting over bit locations other than those determined in (g).

A method of rapidly identifying RFID tags in an RFID system including a reader and a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations, the method comprising:

• (a) issuing from a reader a command indicating a group number y corresponding to a group of bits in the respective tags IDs, followed by a number of timeslots;
• (b) respective tags counting the timeslots and responding in a timeslot corresponding to decimal equivalent of the value contained in group number y;
• (c) recording with the reader, the responses;
• and
• (d) issuing from the reader, commands requesting certain tags to change the values located in their group number y.

An RFID system comprising:

• a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations;
• and
• an RFID reader configured to communicate with the RFID tags, the reader being configured to:
• (a) issue a number n of sequential reads;
• (b) record bit locations at which a response was obtained;
• (c) issue a number m of sequential reads;
• (d) record bit locations at which a response was obtained;
• and
• (e) determine bit locations at which a response was received for both (b) and (d);
• and
• the tags being configured to, during (a), count the reads and respond if bit n of their ID has a first value and configured to, during (c), count the reads and respond if bit m of their ID has a second value different from the first value.

An RFID system comprising:

• a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations;
• and
• a reader configured to communicate with the tags and configured to issue a command indicating a group number y corresponding to a group of bits in the respective tags IDs, followed by a number of timeslots;
• the tags being configured to count the timeslots and respond in a timeslot corresponding to decimal equivalent of the value contained in group number y;
• and
• the reader being further configured to record the responses;
• and
• issue commands requesting certain tags to change the values located in their group number y.