Command sequence for initiating inventorying
Examples are directed to modifying RFID tag inventorying. A sequence of consecutive inventorying commands may be used to initiate an inventory round incorporating a selection functionality for efficient inventorying of large numbers of RFID tags. A command sequence may begin with a first inventorying command followed by one or more subsequent, consecutive inventorying commands, with each inventorying command defining a different filter criterion such that sub-group(s) of RFID tags identified by the combination of filter criteria may participate in the initiated inventory round. All inventorying commands in the sequence share a command code, but each inventorying command also has a starting signal and a continuation indicator, both used to begin, continue, and terminate the sequence.
1 . A Radio Frequency Identification (RFID) integrated circuit (IC) configured to receive and process a sequence of consecutive inventorying commands, the sequence configured to initiate an inventory round, the IC comprising:
a transceiver configured to receive commands and send replies; and
a processing block coupled to the transceiver and configured to:
receive, via the transceiver, a first command preceded by a first starting signal and including both a command code and a continuation indicator;
determine, from at least the command code and the continuation indicator, that the first command is a first inventorying command in the sequence;
receive, via the transceiver, a second command;
determine whether the second command is a second inventorying command in the sequence by at least determining whether the second command has the command code and is preceded by a second starting signal different from the first starting signal; and
if the second command is the second inventorying command in the sequence, then one of initiate the inventory round and await a third command in the sequence, otherwise discard the sequence.
2 . The RFID IC of claim 1 , wherein:
the processing block is further configured to determine that the first command is a first inventorying command in the sequence by determining that the first starting signal is a preamble; and
the second starting signal is a frame-sync.
3 . The RFID IC of claim 2 , wherein the first inventorying command in the sequence is a QueryX command according to the Gen2 Protocol and the second inventorying command in the sequence is a QueryY command according to the Gen2 Protocol.
4 . The RFID IC of claim 1 , wherein the processing block is further configured to determine that the second command is the second inventorying command in the sequence by determining whether the second command was received within a first time duration from the end of the first command.
5 . The RFID IC of claim 4 , wherein the first time duration is a T 8 timeout according to the Gen2 Protocol.
6 . The RFID IC of claim 1 , wherein the processing block is further configured to determine that the second command is the second inventorying command in the sequence by determining that no intervening commands were received between first and second commands.
7 . The RFID IC of claim 1 , wherein the processing block is further configured to, if the second command is the second inventorying command in the sequence, initiate the inventory round if a continuation indicator in the second command indicates that it is the final command in the sequence, otherwise await the third command in the sequence.
8 . The RFID IC of claim 1 , wherein the processing block is configured to discard the sequence by not initiating the inventory round and not awaiting the third command in the sequence.
9 . A method for a Radio Frequency Identification (RFID) integrated circuit to receive and process a sequence of consecutive inventorying commands, the sequence configured to initiate an inventory round, the method comprising:
receiving a first command preceded by a first starting signal and including both a command code and a continuation indicator;
determining, from at least the command code and the continuation indicator, that the first command is a first inventorying command in the sequence;
receiving a second command;
determining whether the second command is a second inventorying command in the sequence by at least determining whether the second command has the command code and is preceded by a second starting signal different from the first starting signal; and
if the second command is the second inventorying command in the sequence then one of initiating the inventory round and awaiting a third command in the sequence, otherwise discarding the sequence.
10 . The method of claim 9 , further comprising determining that the first command is a first inventorying command in the sequence by determining that the first command is preceded by a preamble.
11 . The method of claim 10 , wherein the first inventorying command in the sequence is a QueryX command according to the Gen2 Protocol and the second inventorying command in the sequence is a QueryY command according to the Gen2 Protocol.
12 . The method of claim 9 , further comprising determining that the second command is the second inventorying command in the sequence by determining whether the second command was received within a first time duration from the end of the first command.
13 . The method of claim 12 , wherein the first time duration is a T 8 timeout according to the Gen2 Protocol.
14 . The method of claim 9 , further comprising determining that the second command is the second inventorying command in the sequence by determining that no intervening commands were received between first and second commands.
15 . The method of claim 9 , further comprising, if the second command is the second inventorying command in the sequence, initiating the inventory round if a continuation indicator in the second command indicates that it is the final command in the sequence, otherwise awaiting the third command in the sequence.
16 . The method of claim 9 , further comprising discarding the sequence by not initiating the inventory round and not awaiting the third command in the sequence.
17 . A method for a Radio Frequency Identification (RFID) reader configured to send a sequence of consecutive inventorying commands, the sequence configured to initiate an inventory round, the method comprising:
initiating the sequence by transmitting an initial inventorying command, the initial inventorying command preceded by a preamble and including a first command code and an initial continuation indicator indicating that the initial inventorying command is not the final command in the sequence; and
ending the sequence by transmitting a final inventorying command, the final inventorying command preceded by a frame-sync and including the first command code and a final continuation indicator indicating that the final inventorying command is the final command in the sequence.
18 . The method of claim 17 , further comprising:
continuing the sequence by transmitting another inventorying command between the initial and final inventorying commands, the other inventorying command preceded by a frame-sync and including the first command code and another continuation indicator indicating that the other inventorying command is not the final command in the sequence.
19 . The method of claim 17 , further comprising beginning to transmit the frame-sync of the final inventorying command within a T 8 timeout of the end of an immediately preceding inventorying command in the sequence.
20 . The method of claim 17 , wherein the initial inventorying command is a QueryX command according to the Gen2 Protocol and the final inventorying command is a QueryY command according to the Gen2 Protocol.