Radio frequency identification system with write broadcast capability

A base station for communicating with radio frequency tags in a field of the base station, each of the tags having a tag memory, the tag memory having one or more tag data locations with stored data related to the objects with which the tags are associated, and each of the tag data locations having a tag data address, the base station comprising:

• a computer that develops one or more selection commands specifying data related to the objects with which the tags are associated, and a write broadcast signal directed to no particular destination tag, the write broadcast signal containing a write broadcast command, sent data and zero or more sent addresses;
• a base station transmitter that encodes the one or more selection commands on a radio frequency carrier to create a selection signal specifying data related to the objects with which the tags are associated, and encodes the write broadcast signal on the radio frequency carrier to create a write signal directed to no particular destination tag;
• and
• the base station transmitting the selection signal to all the tags in the field to select a subgroup of a plurality of the tags having the specified data related to the objects with which the tags are associated, causing the subgroup of the plurality of tags to switch to a selected condition, and transmitting the write signal directed only to the sub- group of the plurality of tags that have switched to the selected condition to simultaneously write the sent data only to the tags having the specified data related to the objects with which the tags are associated.

A method comprising the steps of:

• (a) transmitting one or more commands by radio frequency radiation and transmitting a specified memory location of a plurality of tags and transmitting criterion data required to be present in the memory location of the plurality of tags as a criterion for selection thereof;
• (b) at each of a plurality of radio frequency tags, receiving the transmitted specified memory location and the transmitted criterion data, and a plurality of selected radio frequency tags with a match of stored data in the specified memory location with the transmitted criterion data, switching to a predetermined selected state;
• and
• (c) the plurality of selected radio frequency tags having stored data in the specified memory location that matches said criterion data, which stored data represents information relating to respective objects associated with said plurality of selected radio frequency tags and is unrelated to tag identification code of the tags.

A method of selecting a desired subgroup from a group of radio frequency tags in which each of the tags includes a memory storing information relating to the selection of the tag, the method comprising the steps of:

• (a) transmitting a radio frequency command signal to the group of radio frequency tags defining a certain selection criterion related to the objects with which the tags are associated and not related to tag identification codes for identifying the tags, which certain selection criterion is met by a subgroup of a plurality of tags;
• (b) changing the state of the plurality of tags in the subgroup meeting the certain selection criterion such that the plurality of tags meeting the certain selection criterion related to the objects with which the tags are associated and not related to tag identification codes for identifying the tags, remain in the changed state to facilitate subsequent processing;
• (c) transmitting a further radio frequency command directed to the tags in the changed state;
• (d) the plurality of tags in the changed state responding to the further radio frequency command, while tags not in said changed state do not respond to the further radio frequency command.

A transponder comprising:

• (a) a transponder memory having a transponder data location with a stored data value;
• and
• (b) a transponder receiver for receiving a write broadcast signal not associated with said transponder and not directed to any particular transponder, the signal having sent data;
• (c) the transponder writing the sent data to the transponder data location having the stored data value, so that the sent data is thereafter available for a subsequent reading operation where the sent data is read out from the transponder in response to a read command addressed to the transponder data location;
• and
• (d) the transponder in response to the write broadcast signal sending a response if the sent data is different than the stored data value and not sending a response if the sent data is the same as the stored data value;
• wherein a comparator compares the sent data and the data value in the transponder data location of said transponder memory, the receiver writing the sent data to the transponder data location if the sent data is determined by the comparator to be different than the data value previously in the transponder data location of said transponder memory, the transponder sending a response if the sent data is different than the data value previously in the transponder data location of said transponder memory, and not sending a response if the sent data is the same as the data value previously in the transponder data location of said transponder memory.

A radio frequency tagging system comprising

• (a) a base station for communicating with a group of radio frequency tags in a field of the base station, each of the tags having a tag memory;
• (b) the tag memory having one or more tag data locations with stored data related to the objects with which the tags are associated and not related to tag identification code, the base station comprising:
• (c) a computer that develops one or more commands specifying data related to the objects with which the tags are associated and not related to tag identification code;
• (d) a base station transmitter that encodes the one or more commands specifying data related to the objects with which the tags are associated and not related to tag identification code, on a radio frequency carrier to create a group signal, and
• (e) the base station transmitting the group signal to all the tags in the field to select a subgroup of a plurality of the tags based on the specified data related to the objects with which the tags are associated and not related to tag identification code, causing the subgroup of the plurality of tags to respond differently than other tags to a further signal from the base station.