System and Method for Radio Frequency Tag Group Select

A system for selecting a subset of slaves that satisfy a selection criterion, and causing the selected subset of slaves to participate in an identification and isolation process whereby slaves of the selected subset are successively identified and isolated from further participation in such identification and isolation process, said system comprising:

• (a) a master unit for communicating a command containing a selection criterion to a plurality of slaves;
• (b) each slave of said plurality of slaves being in one of three or more different possible conditions during the identification and isolation process;
• (c) a memory in said each slave containing at least one information value for use in evaluation of a selection criterion;
• (d) a receiving unit in said each slave for receiving the command containing the selection criterion from the master unit;
• and
• (e) a processing unit in said each slave that processes the command containing the selection criterion from the master unit;
• (f) the processing units of the slaves having a mode of operation such that a subgroup of slaves that have an information value that satisfies the selection criterion are moved from a first condition to a second condition for participation in an identification and isolation process;
• and
• (g) the processing units of the subgroup of slaves in the second condition having a mode of operation whereby individual slaves of said subgroup can progress to a third condition during the identification and isolation process, with slaves that have progressed to the third condition, and have been identified, being isolated from further participation in the identification and isolation process that continues so as to identify and isolate other of the slaves in the second condition.

A method for selecting a subset of slaves that satisfy at least one selection criterion during a selection process, and then identifying slaves of the selected subset, and causing identified slaves of the selected subset of slaves to be isolated from further participation in the identification process, said method comprising;

• (a) storing at least one information value in each of a plurality of slaves for use in evaluating at least one selection criterion;
• (b) representing at least one selection criterion in at least one selection criterion command;
• (c) communicating the at least one selection criterion command to the plurality of slaves;
• (d) processing the at least one selection criterion command at each of said plurality of slave and deeming certain of the slaves based on storage of the at least one information value to be selected as a result of the selection process;
• (e) carrying out an identification process with respect to the certain slaves deemed selected as a result of the selection process;
• and
• (f) causing slaves that are identified during the identification process of clause (e) to be isolated from responding further in the course of the identification process of clause (e).