Radio frequency identification readers, methods and computer program products for adjusting a query command slot-counter parameter Q

A tangible computer program medium storing a plurality of instructions which, when executed by a processor, causes the processor to perform operations for adjusting a query command slot-count parameter, the operations comprising:

• setting an initial value for the query command slot-count parameter for a first inventory round;
• issuing a query command comprising the initial value for the query command slot-count parameter to a plurality of radio frequency identification tags;
• monitoring replies from the plurality of radio frequency identification tags for identifying the plurality of radio frequency identification tags;
• and
• adjusting, via the processor, the initial value of the query command slot-count parameter for use in a second inventory round by a first amount if no reply is received for the query command that is issued, wherein the first amount is 0.1, and by a second amount different from the first amount if a tag collision reply is received for the query command that is issued, wherein the second amount is a lesser of 1.0 and a value of a formula (0.1)*(Ave_T coll/Ave_T idle), wherein Ave_Tcoll, is an average duration of a collided reply from the plurality of radio frequency identification tags, and wherein Ave_T idle is an average duration of no reply from the plurality of radio frequency identification tags, wherein the Ave_T coll is proximate to 1456 microseconds.

A radio frequency identification reader, comprising:

• a processor of a radio frequency identification controller;
• a transceiver coupled to the radio frequency identification controller;
• a radio frequency antenna coupled to the transceiver;
• wherein the radio frequency antenna transmits a command received from the processor of the radio frequency identification controller via the transceiver and receives responses from a plurality of radio frequency identification tags;
• and
• wherein the processor of the radio frequency identification controller performs operations, the operations comprising:
• setting an initial value for a query command slot-count parameter for a first inventory round;
• issuing a query command comprising the initial value for the query command slot-count parameter to the plurality of radio frequency identification tags;
• monitoring replies from the plurality of radio frequency identification tags for identifying the plurality of radio frequency identification tags;
• and
• adjusting the initial value of the query command slot-count parameter for use in a second inventory round by a first amount if no reply is received for the query command that is issued, wherein the first amount is 0.1, and by a second amount different from the first amount if a tag collision reply is received for the query command that is issued, wherein the second amount is a lesser of 1.0 and a value of a formula (0.1)*(Ave_T coll/Ave_T idle), wherein Ave_T coll, is an average duration of a collided reply from the plurality of radio frequency identification tags, and wherein Ave_Tidle is an average duration of no reply from the plurality of radio frequency identification tags, wherein the Ave_T coll is proximate to 1456 microseconds.