Active ID tags for increased range and functionality

1. An RFID assembly, comprising:

a first part, which includes a unique address indicative of an RFID tag and RFID information associated with said RFID tag;

a second, RFID modem, associated with said first part, which both receives first information from other RFID modems and also sends information in response to an interrogation directed to said unique address;

wherein said RFID modem sending said first information received from other RFID modems, and also sending said RFID information—in response to an interrogation; and

wherein said RFID modem carrying out a probabilistic routing that determines, when said second RFID modem receives a message from at least one other RFID modem, a distance between said second RFID modem, and said at least one other RFID modem, and where said second RFID modem calculates, based on said distance, a probable signal strength to said at least one other RFID modem, a propagation and a transmission power to said at least one other RFID modem, and wherein said probabilistic routing determines a probability of successful transmission to said at least one other RFID modem to determine whether to rebroadcast the message based on said probable signal strength, propagation and transmission power.

2. A tag as in claim 1 , further comprising a microcontroller, controlling operation of said second RF modem to send and receive information.

3. A tag as in claim 1 further comprising a sensor, which senses at least one characteristic of its environment, wherein said second RF modem sends information indicative of the sent characteristics.

4. A tag as in claim 1 , further comprising a substrate, holding said tag.

5. A tag as in claim 4 , wherein said substrate comprises an attachment part that allows the tag substrate to be attached to a support.

6. A tag as in claim 1 , further comprising an interrogator for the tag, wherein said interrogator includes a source of AC power.

7. A tag as in claim 4 , wherein said substrate includes an extra spot which can hold additional active portions.

8. A tag as in claim 1 , wherein said tag relays messages from other tags.

9. A method comprising:

on an RFID tag, receiving information from other RF tags; and

sending both information from other RFID tags, and also information indicative of the RFID tag's own information; and

wherein said sending comprising a probabilistic routing that determines, when said RFID tag receives a message from at least one other RFID tag, a probable distance between said RFID tag and said at least one other RFID tag, and where said RFID tag calculates, based on said distance, a probable signal strength to said at least one other RFID tag, a propagation and a transmission power to said at least one other RFID tag, and wherein said probabilistic routing determines a probability of successful transmission to said at least one other RFID tag to determine whether to rebroadcast the message based on said probable signal strength, propagation and transmission power.

10. A method as in claim 9 , further comprising a microcontroller, controlling operation of said RF modem to send and receive information.

11. A method as in claim 9 further comprising sensing at least one characteristic of an environment of the RFID tag, and sending information indicative of the sensed characteristic.

12. A method as in claim 9 , further comprising mounting electronics on a substrate.

13. A method as in claim 12 , wherein said substrate includes an extra spot which can hold additional active portions.

14. A method as in claim 9 , wherein said tag relays messages from other tags.