KR20100055707A - Rfid reader and transmitter/receiver of baseband modem in rfid reader - Google Patents

Abstract

PURPOSE: An RFID reader and transmitter/receiver of a baseband modem in an RFID reader are provided to reduce the size of a reader rather than a case in which each protocol is individually configured. CONSTITUTION: A frame generator(215) mixes the transmission data generated in an encoder, a CRC(Cyclic Redundancy Check) value generated at a CRC generator, a preamble signal and a frame synchronization signal. The frame generator generates a transmission frame, and transfers the generated transmission frame to an RF transmitter. If a response to the transmission frame at a tag does not exits for a certain time, a timer(216) generates a reception timeout signal to switch a modem in an idle state.

Description

RFID reader and its baseband modem transmitter and receiver {RFID READER AND TRANSMITTER / RECEIVER OF BASEBAND MODEM IN RFID READER}

The present invention relates to an RFID reader, and in particular, in order to support various RFID standards, the RFID standard protocols of ISO 18000-6B, EPC Class-1, and EPC Class-1 Gen2 (ISO 18000-6C) of the UHF band are supported. An RFID reader integrated with a band modem, and a transmitter and a receiver for a baseband modem thereof.

RFID (Radio Frequency Identification) technology is a method of identifying and utilizing information of an entity through wireless-based information exchange. Each object has a device (label type, card type, etc.) called an RFID tag (tag or transponder) attached to it, and a reader in charge of the master function is installed within an effective distance at which information can be exchanged with the tag. do.

RFID system is a wireless identification system that attaches a small tag to various items to acquire and process information, history, and surrounding environment information, and replaces existing barcodes, as well as access control, transportation card, distribution and logistics, It is applied to environmental management and provides various services, and it is a field that can provide a wider range of services by converging with commercial communication infrastructure. Recently, research has been conducted to identify a location of a mobile robot or to service a surrounding object by a service robot in connection with various sensor systems such as an RFID device and an ultrasonic sensor.

RFID uses low frequency band of 125 ~ 135KHz, high frequency band of 13.56MHz, 433.92MHz band, Ultra High Frequency (UHF) band of 860 ~ 960MHz, microwave band of 2.45GHz, etc. Therefore, it can be divided into mutual induction method and electromagnetic wave method. Mutual induction is used for short distances using coil antennas at frequencies below 13.56 MHz, and electromagnetic waves is used for medium distances using frequencies above the UHF band. In particular, the UHF band is currently attracting the most attention as the most suitable band to be applied to various applications including logistics distribution.

International standardization of UHF band RFID is being promoted by ISO / IEC, and EPC global proposes the de facto standardization standard. Representative standards include ISO 18000-6A, ISO 18000-6B, EPC Class-0, EPC Class-1, and EPC Class-1 Gen2 (ISO 18000-6C).

The demand for the RFID system is rapidly increasing in the industrial and logistics fields, and personal demand is expected to increase with the advent of Mobile RFID. Accordingly, RFID readers are being miniaturized from stationary or fixed type to handheld and mobile.

Such a small device requires a multi-protocol modem system on a chip (SoC) that can support multiple standards simultaneously and has built-in computing capabilities.

Until recently, the trend in commercialization has been used in single-chip protocols, such as EPC Class-1 Gen2 (ISO 18000-6C), in chip configurations or in DSP implementations. In other words, there are few cases where a research result that can be commercialized by presenting a multi-protocol is presented.

The purpose of the present invention is to integrate the RFID standard protocols of ISO 18000-6B, EPC Class-1, and EPC Class-1 Gen2 (ISO 18000-6C) of the UHF band into the baseband modem of the RFID reader. In addition, it is possible to reduce the size of the reader rather than to configure each protocol individually, and to provide an excellent RFID reader and its transmitting and receiving device for the baseband modem in terms of manufacturing cost.

The RFID reader of the present invention for achieving the above object, the RF transmitter for up-converting the power of the transmission frame generated by the baseband modem to amplify the power and transmits to the tag side; An RF receiver for down-converting the received frame received from the tag to remove noise and outputting the noise to a baseband modem; A PLL for supplying a local signal for up or down conversion of the RF transmitter and the RF receiver according to a predetermined control signal; And generate a transmission frame to be transmitted to the tag, convert it into an analog signal, output it to the RF transmitter or digitally receive the received frame transmitted from the tag through the RF receiver, and digitally restore power of the RF transmitter and the oscillation frequency of the PLL. Baseband modem for controlling the; characterized in that it comprises a.

The baseband modem includes a modem including EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B and EPC Class-1, which are standard protocols of the UHF band, and an on chip peripheral for connecting a multi-protocol modem. Bus) bus interface, two-channel OPB UART (Universal Asynchronous Receiver and Transmitter) interface, RF controller for controlling the local frequency of the PLL and power of the RF transmitter, and interrupt signals according to various memory and modem operation states. And a CPU for controlling operations of various devices in the baseband modem, an interrupt controller to be generated, a memory in which an internal operation program is stored, a memory controller to control the memory, and a baseband modem.

The baseband transmission apparatus of the RFID reader of the present invention for achieving the above object comprises: a FIFO memory for temporarily storing transmission data; An encoder for encoding the transmission data using any one of Manchester encoding, pulse width encoding or pulse interval encoding according to a standard multi-protocol; A modem state machine which checks a transmission and reception state of a modem through whether the transmission data is transmitted; A CRC generator for generating a cyclic redundancy check (CRC) value of transmission data according to the standard multi-protocol; A frame generator for generating a transmission frame by mixing the transmission data generated by the encoder, the CRC value generated by the CRC generator, a preamble signal, and a frame synchronization signal, respectively, and transferring the generated transmission frame to an RF transmitter; And a timer for generating a reception timeout signal and causing the modem to switch to an idle state when there is no response to the transmission frame in the tag for a predetermined time.

Specifically, the standard multi-protocol is characterized in that the protocol of the UHF band, ISO 18000-6B, EPC (Electronic Product Code) Class-1, and EPC Class-1 Gen2 (ISO 18000-6C).

The encoder uses a Manchester encoder in ISO 18000-6B, a pulse width encoder in EPC (Electronic Product Code) Class-1, and a pulse interval encoder in EPC Class-1 Gen2 (ISO 18000-6C). The FIFO memory is automatically converted to a receiving FIFO memory after all the transmission is completed, the CRC generator, CRC-CCIT type and CRC5 in EPC Class-1 Gen2 (ISO 18000-6C) The CRC value is generated using the type, ISO 18000-6B generates the CRC value using the CRC-CCIT, and EPC Class-1 generates 1Bit odd parity for each field of the transmission frame. It features.

A receiver for a baseband modem of an RFID reader of the present invention for achieving the above object, the high-pass filter for removing the DC offset of the signal input through the analog to digital converter from the RF receiver; A low pass filter for removing noise of a high frequency from a signal input from the high pass filter; A data / clock (D / C) generator for generating data and a clock using the signal input from the low pass filter; A preamble detector which receives data and a clock from the D / C generator, compares a preamble and a frame synchronization signal present therein, and informs a decoder side of the next stage of the start of a received frame; A decoder for decoding the data and the clock inputted from the D / C generator according to standard communication protocol; A CRC checker for performing a CRC operation from the start to the end of the received frame input by the decoder and determining whether the error is normal or an error based on the calculated CRC value when an end signal of the frame is generated; And a FIFO memory for storing the received frame decoded by the decoder in units of bytes.

The decoder, in EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B, which are standard communication protocols, has a data and a clock input from a D / C generator and decodes to '0' when a transition occurs in the middle of each data. If the transition does not occur, it is decoded as '1'. In EPC Class-1, when a transition occurs once in each data, it is decoded as '0' and when there are three transitions, it is decoded as '1'.

As described above, the present invention can simultaneously support various standards, and by securing a multi-protocol RFID reader system on a chip (SoC) incorporating computing functions, a small RFID reader device can be configured.

In addition, the size of the reader can be reduced compared to the existing commercial products using a single protocol, and the cost reduction effect is large when mass-produced chips. In addition, in the case of implementing a standard algorithm by using software, a systematic and in-depth verification process is carried out. If the mass production chip is used, the reliability is high and the error probability is low.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a circuit block diagram illustrating an RFID reader according to the present invention, wherein the RFID reader 100 includes an RF transmitter 110, an RF receiver 150, a PLL 190, a baseband modem 200, and the like. have.

The RF transmitter 110 is configured to up-convert the power of the transmission frame generated by the baseband modem 200 to amplify the power and transmit the same to the tag side.

The RF receiver 150 is configured to down-convert the received frame received from the tag to remove noise and output the noise to the baseband modem 200.

The phase locked loop (PLL) 190 is configured to supply a local signal for up or down conversion of the RF transmitter 110 and the RF receiver 150 according to a predetermined control signal.

The baseband modem 200 generates a transmission frame to be transmitted to the tag and converts it into an analog signal and outputs the RF frame to the RF transmitter 110 or receives the received frame transmitted from the tag through the RF receiver 150 and digitally restores it. In addition, it is configured to control the power amplification of the RF transmitter 110 and the oscillation frequency of the PLL (190).

That is, the RF transmitter 110 is composed of an I channel and a Q channel, and each channel includes a band pass filter 111 for selectively filtering I and Q signals respectively input from the baseband modem 200, and an input. The upmixer 112 up-converts the baseband signal input from the bandpass filter 111 to a predetermined RF frequency according to the local signal. The RF transmitter 110 includes an adder 113 for summing signals passing through the I and Q channels, a power amplifier 114 for amplifying the power of the signal passing through the adder 113, and the power. The filter 115 includes a filter 115 for filtering a signal of a specific frequency band among the signals output from the amplifier 114 and outputting the filtered signal to the antenna 116.

The RF receiver 150 filters a signal of a specific frequency band among the signals received through the antenna 151 and outputs the signal, and a noise of the signal output through the filter 152 is reduced and the signal is amplified. It consists of a low noise amplifier (153). The RF receiver 150 separates the signal output through the low noise amplifier 153 into an I channel and a Q channel, and each channel is input from the low noise amplifier 153 according to the input local signal. A down mixer 154 for down-converting an RF signal to a baseband, a band pass filter 155 for filtering an I signal or a Q signal input from the down mixer, and a signal input from the band pass filter 155 After the amplification, the amplifier 156 is output to the I and Q ports of the baseband modem 200.

The PLL 190 is configured to vary the frequency of the local signal according to the control signal output from the baseband modem 200 and to supply the mixers 112 and 154.

In addition to transmitting and receiving data, the baseband modem 200 includes a function of controlling the power amplifier 114 of the RF transmitter 110 and a function of controlling the PLL 190 generating a local signal.

Meanwhile, in the digital transmitter of the baseband modem 200, a block for generating transmission data, a block capable of converting a modulation depth, a raised cosine filter (RCF), and a PSK signal It consists of a Hilbert Transform that creates a. The signal generated by the digital transmitter is transmitted to the RF transmitter 110 through a digital to analog converter (DAC), the RF transmitter 110 is a single side band transmission (SSB), DSB through the mixer 112 A double side band transmission signal is generated and transmitted to the air through the antenna 116. The signal transmitted through the antenna is lost in the air (Free Space Loss), the receiving part of the tag, the signal transmitted from the reader 100 and the reflected signal, AWGN noise (Additive White Gausian Noise) The back is added.

The signal reaching the tag is back-scattered and sent to the RF receiver 150 of the reader 100. The RF receiver 150 of the reader 100 reflects the signal sent from the tag and the signal of the tag, AWGN. The noise and the signal reflected from the reader are added together to be received. The RF receiver 150 of the reader 100 down-converts the received signal through the mixer 154 and removes the DC offset and noise through the filter 155. The digital receiver of the baseband modem 200 receives the I and Q channel signals through a predetermined analog to digital converter (ADC) and restores the data transmitted from the tag.

In the above RF system, the local oscillator phase noise, transmission / reception channel coupling, reflection environment, AWGN noise, DC offset, I / Q mismatch, etc., affect performance. Among them, it is preferable to add a filter in the digital receiver of the baseband modem 200 in order to reduce the effects on DC offset and AWGN noise.

EPC Class-1 Gen2 (ISO 18000-6C), an RFID standard of the UHF band, encodes data at the time of transmission and uses DSB-ASK, SSB-ASK, or PR-ASK after encoding PIE (Pulse Interval Encoding). Other RFID standards in the band, ISO 18000-6B and EPC Class-1, use ASK.

In EPC Class-1 Gen2 (ISO 18000-6C), a frame sync signal (sync) or preamble is placed in front of data transmitted from a reader. The preamble is used when the Query command is used and all other commands use the frame synchronization signal. The structure of the preamble is composed of a start delimiter, a data-0 symbol, an RTcal (calibration) symbol, and a TRcal symbol as shown in FIG. 2A. The structure of the frame sync includes a start delimiter as shown in FIG. 2B, It consists of data-0 symbol and RTcal symbol.

The starting delimiter is 12.5 ㎲ 5%, and RTcal is equal to the length of the data-0 symbol plus the length of the data-1 symbol. In the tag, RTcal / 2 is calculated and called Pivot. When a signal shorter than the pivot comes in, the data is judged as '0', and when a signal longer than the Pivot is received, the data is determined as '1'. TRcal is used to determine the back-scatter link frequency of the tag.

Tari means a period of data-0 and may have values of 6.25 ms, 12.5 ms, and 25 ms 1%. The transmission data uses a pulse interval encoding scheme, and a data rate may have a maximum of 160 Kbps to 20 Kbps.

The tag responds in a back-scatter manner and uses ASK or PSK. The encoding uses FM0 or Miller subcarrier scheme.

The link frequency LF is determined by the TRcal value. The calculation method is as shown in Equation 1 below, and the DR may have a value of 8 or 64/3. Therefore, the FM0 method has a data rate range of up to 640 Kbps to 40 Kbps, and the Miller method has a range of 320 Kbps to 5 Kbps.

ISO 18000-6B uses Manchester for transmission and FM0 for reception. The transmit / receive data rate has 10Kbps or 40Kbps.

 In EPC Class-1, the pulse width method is used for transmission and the FM0 method is used for reception. The transmit data rate is 70.18 Kbps or 15 Kbps and the receive data rate is 140.35 Kbps or 30 Kbps.

FIG. 3 is a diagram illustrating a structure of a system on a chip (SoC) of a baseband modem of an RFID reader according to the present invention. As shown, the SoC is a multi-protocol modem (201, 202; EPC Class-1 Gen2 and ISO 18000). -6B), On chip Peripheral Bus (OPB) bus 203, two-channel OPB UART (Universal Asynchronous Receiver and Transmitter) interface 204, RF controller 205, CPU 206, interrupt controller 207 , A memory 208, a memory controller 209, and the like.

That is, the baseband modem 200 is a multi-protocol including modems 201 and 202 including EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B and EPC Class-1, which are standard protocols of the UHF band. An OPB bus interface 203 for connecting a modem, an OPB UART interface 204 for two channels, an RF controller 205 for controlling the local frequency of the PLL 190 and the power of the RF transmitter 110; An interrupt controller 207 for generating an interrupt signal according to various memory and modem operation states, a memory 208 in which an internal operation program is stored, a memory controller 209 for controlling the memory, and various kinds of the baseband modem 200. And a CPU 206 or the like for controlling the operation of the device.

In order to configure the SoC of the baseband modem 200, the CPU 206 used Microblaze, which is a 32-bit RISC processor of Xilinx, as an Intellectual Property (IP), and used IBM CoreConnect Technology provided by Xilinx as an IP as a system bus. do. Then, an OPB bus interface 203 is added to connect a multiprotocol modem to the OPB, and a two-channel UART interface 204 having an OPB bus interface is added for communication with the outside. The UART interface 204 changes the parallel signal in parallel or serially changes the signal output to the outside in order to quickly process the serial signal input from the outside.

In addition, the RF controller 205 may be added to control the RF transmitter 110 and the PLL 190. Such an implementation is merely an embodiment, and the SoC may be configured using hardware of various products.

4 is a detailed block diagram illustrating the multi-protocol modem of FIG. 3 according to the present invention. The multi-protocol modems 201 and 202 analyze a transmitter 210 for supplying data and power to a tag and data sent from the tag. It consists of a receiver 250 for transmitting to the host. Of course, the transmitter / receiver 210, 250 is controlled by the CPU 206, and communication with the host is performed through the UART interface 204.

FIG. 5 is a block diagram showing a transmitter 210 of the RFID reader modem of FIG. 4 according to the present invention, and FIG. 9 is a block diagram showing the receiver 250 of the RFID reader modem of FIG. 4 according to the present invention.

As shown in FIG. 5, the transmitter 210 (TX) of the RFID reader modem includes a FIFO (First-In First_Out) memory 211, an encoder 212, a cyclic redundancy check (CRC) generator 213, and a modem state machine 214. ), And a frame generator 215 and the like.

The FIFO memory 211 is configured to temporarily store transmission data to be transmitted by the tag.

The encoder 212 is configured to encode the transmission data using any one of Manchester encoding, pulse width encoding or pulse interval encoding according to a standard multi-protocol.

The modem state machine 214 is configured to check the transmission and reception status of the modem 200 through the transmission of the transmission data.

The CRC generator 213 is configured to generate a cyclic redundancy check (CRC) value of transmission data according to the standard multi-protocol.

The frame generator 215 generates a transmission frame by mixing the transmission data generated by the encoder 212 and the CRC value, the preamble signal, and the frame synchronization signal generated by the CRC generator 213, respectively. It is configured to deliver the frame to the RF transmitter (110).

The timer 216 generates a reception timeout signal to cause the modem to switch to an idle state when there is no response to the transmission frame in the tag for a predetermined time.

Meanwhile, the encoder 212 includes a Manchester encoder 212, a pulse width encoder 212, a pulse interval encoder 212, and the like. In order to send transmission data, the ISO 18000-6B uses the Manchester encoder 212. In the EPC Class-1, the pulse width encoder 212 is used, and in the EPC Class-1 Gen2 (ISO 18000-6C), the pulse interval encoder 212 is used. Each encoder 212 may change the data rate.

Commands that can be issued by the computing CPU for transmission and reception are composed of a transmission, a transmission, and a reception, and the transmission and reception operate to automatically switch to a reception mode after transmission. In ISO 18000-6B, Resync and Write commands may be added in addition to the above commands.

The modem state machine 214 transitions to a state as shown in FIG. 6, and the state value is used to control the transmission (TX) and the reception (RX) and simultaneously informs the system of the current state. The timer 216 generates a reception timeout signal when there is no response from the tag for a certain period of time, thereby moving the modem to an idle state so that the reader can perform another command.

The FIFO memory 211 is configured to store transmission data up to 64 bytes, and when transmitting data of 64 bytes or more, the transmission data is additionally added to the FIFO memory 211 when the modem state is in the transmission state after the transmission or reception or transmission command is performed. It is configured to extend the length of the transmission data by putting it. The FIFO memory 211 automatically switches to the receiving FIFO memory 257 after all transmissions are completed.

The IRQ controller 217 generates an interrupt to the CPU 206 by viewing the states of the IRQ enable register, modem state, and FIFO memory, and displays the current interrupt status.

In EPC Class-1 Gen2 (ISO 18000-6C), CRC is generated by using CRC-CCIT of FIG. 7 and CRC5 of FIG. 8, and ISO 18000-6B uses CRC-CCIT in CRC generator 213 to generate CRC. It generates and transmits it in the second half of the transmission data. In EPC Class-1, odd parity of 1 bit is generated and transmitted for each field.

The frame generator 215 combines the preamble and the frame start signal (Sync Start delimiter), the data generated by each encoder 212, and the CRC data, and transmits the signal to the RF transmitter 110.

Meanwhile, in FIG. 4, the structure of the receiver 250 is the same as that of FIG. 9, and the receiver 250 of FIG. 9 includes a filter 251, a data & clock (D / C) generator 252, a preamble detector 253, The decoder 254, the CRC checker 256, the FIFO memory 257, etc. are comprised. The filter 251, the D / C generator 252, the preamble detector 253, and the decoder 254 are separately configured for each channel (I channel and Q channel), but may also be configured as one channel. Of course.

The filter 251 is composed of a high pass filter (HPF) and a low pass filter (LPF), the high pass filter (HPF) is the DC of the signal input from the RF receiver 150 through a predetermined analog-to-digital converter The low pass filter LPF is configured to remove the noise of the high frequency of the signal input from the high pass filter HPF.

The D / C generator 252 is configured to generate data and a clock using the signal input from the low pass filter LPF, respectively.

The preamble detector 253 is configured to receive the data and the clock from the D / C generator 252, compare the preamble and the frame synchronization signal therein, and notify the decoder 254 at the later stage of the start of the received frame. have.

The decoder 254 is configured to decode the data and the clock input from the D / C generator 252 according to standard communication protocol.

The CRC checker 256 performs a CRC operation from the start to the end of the received frame input by the decoder 254, and when the end signal of the frame is generated, the CRC checker 256 is configured to determine whether it is normal or an error. .

The FIFO memory 257 is configured to store received frames decoded by the decoder 254 in units of bytes.

In addition, reference numeral 255 is a selector, which is operated according to a control signal of the CPU 206 to selectively output signals input from the plurality of decoders 254. That is, as illustrated in FIG. 9, the filter 251, the D / C generator 252, the preamble detector 253, and the decoder 254 are provided in plural, and the selector 255 is input from the plurality of decoders 254. Allow the signal to be output selectively.

The receiver 250 configured as described above finds the preamble signal from the signal sent from the tag, and then decodes the received data and stores the received data in the FIFO memory 257 and transmits its state to the CPU 206 through an interrupt.

The high pass filter HPF receives a signal from the RF receiver 150 through a predetermined ADC and removes the DC offset generated by the RF receiver 150. The signal from the high pass filter (HPF) is passed to the input of the low pass filter (LPF), and the low pass filter (LPF) removes noise of a higher frequency than the signal sent from the tag to prevent an error in data decoding. Can be.

The two filters HPF and LPF may adjust the characteristics of the filter by changing the coefficient value through the CPU 206.

The D / C generator 252 generates the data and the clock using the signal from the filter (LPF), and the signal sent from the tag as shown in FIG. have.

The FM0 decoder 254 for EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B has a clock and the data sent from the D / C generator 252 and a '0' when a transition occurs in the middle of each signal data. If no transition occurs, decode it to '1'. In the case of EPC Class-1, if a transition occurs once in each data time, it is decoded as '0' and if there are three transitions, it is decoded as '1'.

Whenever 8 bits are decoded, a write signal and 8 bit data are transferred to the FIFO memory 257 to be stored in a byte unit in the FIFO memory 257.

The preamble detector 253 receives the data and the clock from the D / C generator 252 and compares the preamble and the frame synchronization signal therein to the FM0 decoder 254 and the EPC Class-1 decoder 254. This sync signal is used to signal the start of a data frame.

In the CRC checker 256, both the ISO 1800-6B and the EPC Class-1 use the CRC-CCIT CRC, initialize the CRC to the synchronization signal, perform a CRC operation from the start of the data to the end of the frame. When the end of frame signal is generated, it is determined whether the error is normal or not by looking at the calculated CRC value.

Although not shown in detail, a collision detector included in the preamble detector 253 and a frame end detector included in the CRC checker 256 are configured in the receiver 250 to receive a signal from the low pass filter LPF. A collision signal and an end frame signal may be generated, and an error flag register may indicate a CRC, a collision, an FIFO memory 257 overflow error, and the like.

In FIG. 3, the FIFO memories 211 and 257 of the transmitter 210 and the receiver 250 may be commonly used to reduce the chip area.

According to the present invention, it is possible to reduce the size compared to existing commercial products that implement a single protocol, and the price reduction effect is great when mass-producing chips.

In the present invention, by integrating a multi-protocol algorithm supporting the ISO 18000-6B, EPC Class-1, and EPC Class1 Gen2 standards of the UHF band into the baseband modem of the RFID reader, coding the individual protocols in the C language in the DSP. Faster processing speeds are possible than with implementation.

In addition, it is possible to miniaturize the baseband modem than to configure each protocol individually, and may be applied in various fields in the future. It can be used for portable reader, small fixed reader, small reader module for location recognition and surrounding object recognition for service robot.

Preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit of the present invention. Therefore, such modifications, changes and additions should be determined not only by the claims below, but also by equivalents to those claims.

1 is a circuit block diagram showing an RFID reader according to the present invention.

2A and 2B are diagrams illustrating structures of a frame synchronization signal and a preamble according to a standard communication protocol, respectively.

3 is a view showing the structure of a SoC (System on a Chip) of the baseband modem of the RFID reader according to the present invention.

4 is a detailed block diagram illustrating the multi-protocol modem of FIG. 3 according to the present invention.

5 is a block diagram illustrating a transmitter of the RFID reader modem of FIG. 4 according to the present invention.

6 is a diagram illustrating a modem state transition according to the present invention.

7 and 8 are diagrams for explaining a CRC generation method according to the CRC type of the standard communication protocol.

9 is a block diagram illustrating a receiver of the RFID reader modem of FIG. 4 according to the present invention.

FIG. 10 is a diagram illustrating an error tolerance range of received data when generating data and a clock in the D / C generator of FIG. 9.

* Explanation of symbols for the main parts of the drawings

100: RFID reader 110: RF transmitter

150: RF receiver 190: PLL

200: baseband modem 201,202: multi-protocol modem

206: CPU 210: transmitter

211: FIFO Memory 212: Encoder

213: CRC Generator 214: Modem State Machine

215: frame generator 250: receiver

251: Filter (HPF, LPF) 252: Data & clock generator

253: preamble detector 254: decoder

256: CRC checker 257: FIFO memory

Claims (9)

A FIFO memory for temporarily storing transmission data; An encoder for encoding the transmission data using any one of Manchester encoding, pulse width encoding or pulse interval encoding according to a standard multi-protocol; A modem state machine which checks a transmission and reception state of a modem through whether the transmission data is transmitted; A CRC generator for generating a cyclic redundancy check (CRC) value of transmission data according to the standard multi-protocol; A frame generator for generating a transmission frame by mixing the transmission data generated by the encoder, the CRC value generated by the CRC generator, a preamble signal, and a frame synchronization signal, respectively, and transferring the generated transmission frame to an RF transmitter; And And a timer for generating a reception timeout signal to switch the modem to an idle state when there is no response to the transmission frame in the tag for a predetermined time. The method according to claim 1, The standard multi-protocol is a protocol of the UHF band, which is ISO 18000-6B, EPC (Electronic Product Code) Class-1, and EPC Class-1 Gen2 (ISO 18000-6C). Transmission device for modem. The method according to claim 1 or 2, The encoder uses a Manchester encoder in ISO 18000-6B, a pulse width encoder in EPC (Electronic Product Code) Class-1, and a pulse interval encoder in EPC Class-1 Gen2 (ISO 18000-6C). A transmitter for a baseband modem of an RFID reader. The method according to claim 1 or 2, And the FIFO memory is automatically switched to a receiving FIFO memory after all transmissions are completed. The method according to claim 2, The CRC generator generates a CRC value using an CRC-CCIT type and a CRC5 type in an EPC Class-1 Gen2 (ISO 18000-6C), and an ISO 18000-6B generates a CRC value using a CRC-CCIT. In EPC Class-1, an RFID reader baseband modem transmitting apparatus generates 1 bit odd parity for each field of a transmission frame. A high pass filter for removing a DC offset of a signal input through an analog-digital converter from the RF receiver; A low pass filter for removing noise of a high frequency from a signal input from the high pass filter; A data / clock (D / C) generator for generating data and a clock using the signal input from the low pass filter; A preamble detector which receives data and a clock from the D / C generator, compares a preamble and a frame synchronization signal present therein, and informs a decoder side of the next stage of the start of a received frame; A decoder for decoding the data and the clock inputted from the D / C generator according to standard communication protocol; A CRC checker for performing a CRC operation from the start to the end of the received frame input by the decoder and determining whether the error is normal or an error based on the calculated CRC value when an end signal of the frame is generated; And And a FIFO memory for storing the received frame decoded by the decoder in units of bytes. The method according to claim 6, The decoder, in EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B, which are standard communication protocols, has a data and a clock input from a D / C generator and decodes to '0' when a transition occurs in the middle of each data. If no transition occurs, it is decoded as '1'. In EPC Class-1, if a transition occurs once in each data, it is decoded as '0' and when it occurs three times, it is decoded as '1'. Receiver for baseband modems. An RF transmitter which up-converts the frequency of the transmission frame generated by the baseband modem, amplifies the power, and transmits the power to the tag; An RF receiver for down-converting the received frame received from the tag to remove noise and outputting the noise to a baseband modem; A PLL for supplying a local signal for up or down conversion of the RF transmitter and the RF receiver according to a predetermined control signal; And After generating a transmission frame to be transmitted to a tag and convert it into an analog signal, output it to an RF transmitter or digitally receive a received frame transmitted from the tag through an RF receiver, and digitally restore power of the RF transmitter and the oscillation frequency of the PLL. RFID reader comprising a; baseband modem for controlling. The method according to claim 8, The baseband modem, Modems including EPC Class-1 Gen2 (ISO 18000-6C) and ISO 18000-6B and EPC Class-1, which are standard protocols in the UHF band, an On Chip Peripheral Bus (OPB) bus interface for connecting multi-protocol modems, An OPB UART (Universal Asynchronous Receiver and Transmitter) interface of two channels, an RF controller for controlling the local frequency of the PLL and the power of the RF transmitter, an interrupt controller for generating an interrupt signal in accordance with various memory and modem operation states, And a memory for storing an internal operation program, a memory controller for controlling the memory, and a CPU for controlling operations of various devices in the baseband modem.

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