RFID huffman encoded commands

• US 20060143163A1
• Filed: 11/09/2005
• Published: 06/29/2006
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Curtis L. Carrender, John Stephen Smith
• Inventors: Smith, John Stephen, Carrender, Curtis L.
• Granted Patent: US 7,562,083 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

Methods and Apparatuses for RFID with Huffman encoded commands are provided. Each command of a plurality of commands is Huffman encoded. A rarely used command of the plurality of commands has more command bits than another command of the plurality of commands. The plurality of commands includes QueryA, QueryB, QueryRep, ACK, and NAK.

Claims

1-94. -94. (canceled)

95. An RFID reader comprising:

first and second antennas;

a transmitter coupled to the first antenna;

a receiver coupled to the second antenna; and

a microprocessor configured to transmit to a tag a plurality of Huffman encoded commands,

wherein a first command of the plurality of encoded commands rarely used relative to a second command has more command bits than the second command.

96. The RFID reader of claim 95 operating in a frequency range of about 900 megahertz.

97. The RFID reader of claim 95 wherein the microprocessor is a microcontroller.

98. The RFID reader of claim 95 further comprising dynamic random access memory and a memory controller that controls the operation of the memory.

99. The RFID reader of claim 95 further comprising a network interface.

100. The RFID reader of claim 99 wherein the network interface is an Ethernet interface.

101. The RFID reader of claim 95 wherein the plurality of encoded commands includes a query command and a handshake command, the query command having fewer command bits than the handshake command.

102. The RFID reader of claim 101 wherein the query command comprises 6 command bits and the handshake command comprises 7 command bits.

103. The RFID reader of claim 101 wherein the plurality of encoded commands further includes a NAK command preventing a state change in the tag, the NAK command having more command bits than both the query and handshake commands.

104. The RFID reader of claim 95 wherein a QueryRep command has fewer command bits than a QueryA command.

105. The RFID reader of claim 95 wherein a QueryRep command has fewer command bits than a NAK command.

106. The RFID reader of claim 105 wherein an ACK command has fewer command bits than the NAK command.

107. The RFID reader of claim 95 wherein the reader transmits a signal to the tag which signal is used by the tag to synchronize an internal clock in the tag.

108. An RFID tag comprising:

an antenna, the antenna configured to receive RF energy to power operation of the tag; and

an integrated circuit coupled to the antenna, the integrated circuit comprising;

a receiver; and

a state machine configured to implement a command protocol, the command protocol including a plurality of Huffman encoded commands,

wherein a rarely used command of the plurality of encoded commands has more command bits than another command of the plurality of encoded commands.

109. The RFID tag of claim 108 wherein the tag receives a signal from a reader and uses the signal to synchronize an internal clock in the tag.

110. An RFID tag comprising:

an antenna, the antenna configured to receive RF energy to power operation of the tag; and

an integrated circuit coupled to the antenna, the integrated circuit comprising;

a receiver; and

logic configured to implement a command protocol, the command protocol including a plurality of Huffman encoded commands, wherein a rarely used command of the plurality of encoded commands has more command bits than another command of the plurality of encoded commands.

111. The RFID tag of claim 110 wherein the plurality of encoded commands includes a query command and a handshake command, the query command having fewer command bits than the handshake command.

112. The RFID tag of claim 111 wherein the query command comprises 6 command bits and the handshake command comprises 7 command bits.

113. The RFID tag of claim 111 wherein the plurality of encoded commands further includes a NAK command preventing a state change in the tag, the NAK command having more command bits than both the query and handshake commands.

114. The RFID tag of claim 110 wherein the integrated circuit is configured for fluidic self-assembly.

115. The RFID tag of claim 110 wherein the integrated circuit further comprises a switch coupled to a transmitter and the receiver.

116. The RFID tag of claim 110 wherein the tag receives a signal from a reader and uses the signal to generate an internal clock in the tag.

117. A method of operating an RFID reader, the method comprising:

transmitting a first command of a plurality of Huffman encoded commands;

receiving a response from a tag; and

transmitting a second command of the plurality of Huffman encoded commands, the second command being rarely used relative to the first command, and the second command having more command bits than the first command.

118. The method of claim 117 wherein the first command is a query command and the second command is a handshake command.

119. The method of claim 118 wherein the query command comprises 6 command bits and the handshake command comprises 7 command bits.

120. The method of claim 118 wherein the plurality of encoded commands further includes a NAK command preventing a state change in a tag, the NAK command having more command bits than both the query and handshake commands.

121. The method of claim 117 wherein the first command is a QueryRep command and the second command is a QueryA command.

122. The method of claim 117 wherein the first command is a QueryRep command and the second command is a NAK command.

123. The method of claim 117 further comprising transmitting a third command, the third command being an ACK command and having fewer bits excluding data bits than the NAK command.

124. The method of claim 117 wherein the reader includes first and second antennas.

125. The method of claim 117 further comprising transmitting a signal to the tag, which signal is used by the tag to synchronize an internal clock in the tag.

126. A machine readable medium containing instructions which when executed on a data processing system causes the system to transmit a plurality of Huffman encoded commands, wherein a first command of the plurality of encoded commands rarely used relative to a second command has more command bits than the second command.

127. The medium of claim 126 wherein a QueryRep command of the plurality of encoded commands has fewer command bits than a QueryA command.

128. The medium of claim 126 wherein a QueryRep command of the plurality of encoded commands has fewer command bits than a NAK command.

129. The medium of claim 128 wherein an ACK command of the plurality of encoded commands has fewer command bits than the NAK command.

130. The medium of claim 126 wherein the data processing system is coupled to a manufacturing tool.

131. The medium of claim 126 wherein the instructions further causes the system to transmit a signal to a tag, which signal is used by the tag to synchronize an internal clock in the tag.

132. An RFID reader comprising:

an antenna;

a transmitter; and

a microprocessor configured to broadcast a plurality of commands with the antenna and transmitter, each command of the plurality of commands being Huffman encoded, whereby a rarely used command of the plurality of commands has more command bits than another command of the plurality of commands and command bits of any command is not a prefix for another command to comply with Huffman encoding.

133. The reader of claim 132 further comprising an Ethernet network interface.

134. The reader of claim 132 wherein the reader transmits a signal to a tag which signal is used by the tag to synchronize an internal clock in the tag.