Patent ID: 8193913

Claim:
In a radio frequency identification system of elements including at least one reader and a plurality of tags, including a first tag and a second tag, a method for communicating between the at least one reader and the tags, the method comprising: addressing a wide-band-message signal by including in said signal a first-tag identifier of the first tag, thereby producing an addressed wide-band-message signal with a destination being the first tag along with other tag identifiers for respective other tags forming a first set of addressed tags; transmitting said addressed wide-band-message signal by the reader; determining a probability of collision for the addressed wide-band-message signal transmitted relative to a threshold and not conducting transmission of an additional addressed wide-band-message signal responsive to the probability of collision being below the threshold; transmitting the additional addressed wide-band-message signal addressed for a second set of addressed tags responsive to the probability of collision exceeding the threshold, the second set of addressed tags being a smaller set of tags than the first set of addressed tags; waiting to receive by the first tag said addressed wide-band-message signal; and upon receiving said addressed wide-band message signal and recognizing said identifier, responding to said addressed wide-band-message signal by transmitting by the first tag an addressed wide-band response signal.