WO2009082742A1 - Rfid network control and redundancy - Google Patents
Rfid network control and redundancy Download PDFInfo
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- WO2009082742A1 WO2009082742A1 PCT/US2008/088048 US2008088048W WO2009082742A1 WO 2009082742 A1 WO2009082742 A1 WO 2009082742A1 US 2008088048 W US2008088048 W US 2008088048W WO 2009082742 A1 WO2009082742 A1 WO 2009082742A1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W76/00—Connection management
- H04W76/10—Connection setup
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/18—Service support devices; Network management devices
Definitions
- the present inventions relate generally to an RFID network control device
- RCD radio frequency identification
- the inventions are of particular use in RFID applications having a large number of antennas and/or other peripheral devices in which it is desirable to minimize the number of relatively expensive readers and/or hosts. This includes but is not limited to RFID smart shelving and other smart or RFID enabled retail fixture systems.
- the signals carried and directed by the routing device of the embodiments described herein may be RFID commands for communication between RFID readers and tags, or those signals may be control signals used to set switches, power on or off devices on the network, identify and/or configure devices on the network, or carry out other functions necessary to the effective operation of the RFID network.
- RFID Radio frequency identification
- transponders or tags are attached to or placed inside the items to be tracked, and these transponders or tags are in at least intermittent communication with transceivers or readers which report the tag (and, by inference, item) location to people or software applications via a network to which the readers are directly or indirectly attached.
- RFID applications include tracking of retail items being offered for public sale within a store, inventory management of those items within the store backroom, on store shelving fixtures, displays, counters, cases, cabinets, closets, or other fixtures, and tracking of items to and through the point of sale and store exits.
- Item tracking applications also exist which involve warehouses, distribution centers, trucks, vans, shipping containers, and other points of storage or conveyance of items as they move through the retail supply chain.
- Another area of application of RFID technology involves asset tracking in which valuable items (not necessarily for sale to the public) are tracked in an environment to prevent theft, loss, or misplacement, or to maintain the integrity of the chain of custody of the asset.
- These applications of RFID technology are given by way of example only, and it should be understood that many other applications of the technology exist.
- the RFID tag is powered by the electromagnetic carrier wave. Once powered, the passive tag interprets the radio frequency (RF) signals and provides an appropriate response, usually by creating a timed, intermittent disturbance in the electromagnetic carrier wave.
- RF radio frequency
- RFlD systems typically use reader antennas to emit electromagnetic carrier waves encoded with digital signals to RFID tags. As such, the reader antenna is a critical component facilitating the communication between tag and reader, and influencing the quality of that communication.
- a reader antenna can be thought of as a transducer which converts signal-laden alternating electrical current from the reader into signal-laden oscillating electromagnetic fields or waves appropriate for a second antenna located in the tag, or alternatively, converts signal-laden oscillating electromagnetic fields or waves (sent from or modified by the tag) into signal-laden alternating electric current for demodulation by and communication with the reader.
- Types of antennas used in RFID systems include patch antennas, slot antennas, dipole antennas, loop antennas, and many other types and variations of these types.
- the detection range of passive RFID systems is typically limited by signal strength over short ranges, for example, frequently less than a few feet for passive UHF RFID systems. Due to this read range limitation in passive UHF RFID systems, many applications make use of portable reader units or mobile carts with readers and antenna wands tethered to the readers with cables. These portable or mobile reader systems may be manually moved around a group of tagged items in order to detect all the tags, particularly where the tagged items are stored in a space significantly larger than the detection range of a stationary or fixed reader equipped with one fixed antenna.
- portable UHF reader and antenna units suffer from several disadvantages. The first involves the cost of human labor associated with the scanning activity.
- a large fixed reader antenna driven with sufficient power to detect a larger number of tagged items may be used.
- such an antenna may be unwieldy, aesthetically displeasing, and the radiated power may surpass allowable legal or regulatory limits.
- these reader antennas are often located in stores or other locations were space is at a premium and it is expensive and inconvenient to use such large reader antennas.
- a single large antenna is used to survey a large area (e.g., a set of retail shelves, or an entire cabinet, or entire counter, or the like), it is not possible to resolve the location of a tagged item to a particular spot on or small sub-section of the shelf fixture.
- U.S. Patent 7,132,945 describes a shelf system which employs a mechanized scanning antenna. This approach makes it possible to survey a relatively large area and also eliminates the need for human labor.
- the introduction of moving parts into a commercial shelf system may prove impractical because of higher system cost, greater installation complexity, and higher maintenance costs, and inconvenience of system downtime, as is often observed with machines which incorporate moving parts.
- Beam-forming smart antennas can scan the space with a narrow beam and without moving parts.
- active devices they are usually big and expensive if compared with passive antennas.
- the antennas themselves are small, and thus require relatively little power to survey the space surrounding each antenna.
- the system itself requires relatively little power (usually much less than 1 watt).
- the system can thus survey a large area with relatively little power.
- the UHF antennas used in the antenna array are generally small and (due to their limited power and range of less than 1-12 inches) survey a small space with a specific known spatial location, it must also be true that the tagged items read by a specified antenna in the array are also located to the same spatial resolution of 1-12 inches.
- systems using fixed arrays of small antennas can determine the location of tagged items with more precision than portable RFID readers and systems using a small number of relatively large antennas. Also, because each antenna in the array is relatively small, it is much easier to hide the antennas inside of the shelving or other storage fixture, thus improving aesthetics and minimizing damage from external disruptive events (e.g., children's curiosity-driven handling, or malicious activity by people in general). Also, an array of fixed antennas involves no moving parts and thus suffers from none of the disadvantages associated with moving parts, as described above. Also, small antennas like those used in such antenna arrays may be cheaper to replace when a single antenna element fails (relative to the cost of replacing a single large antenna). Also, fixed arrays of antennas do not require special manual labor to execute the scanning of tagged items and, therefore, do not have associated with them the high cost of manual labor associated with portable reader and antenna systems, or with mobile cart approaches.
- FIG. 1 is a schematic illustrating a typical prior art approach. Individual RFID antennas 100 are connected to a central common RF communications cable 105 using simple switches or relays 110. Over the common cable, the antennas are driven from an RFTD reader 120 which generates outgoing and interprets incoming RF signals, referred to herein as "RFID traffic signals" or just "traffic signals”.
- RFID traffic signals or just "traffic signals”.
- RFID traffic signals deals specifically with the signals used to communicate between RFID readers and tags, but in some cases specifically noted in this document “RFTD traffic” could also include device control and command signals.
- RFID traffic refers to signals to and from antennas for communication with RFID tags.
- the reader is controlled by commands received from a computer 130.
- tags or transponders
- the computer 130 selects an antenna and sends the identity of the selected antenna to the switch controller 150, which in turn activates the selected antenna using a control line 115 coupled between the switch controller 150 and the antenna's associated relay 110.
- the other antennas are deactivated over their respective control lines.
- the computer 130 then instructs the reader 120 to collect the required information, and the results from the reader 120 are returned to the computer 130 and associated with the active antenna.
- the technology used to control the multiplexers is crude, requiring manual configuration of the network, and not allowing failover from one reader to another when a reader on the network is disabled. That is, these crude network implementation based on simple multiplexers involve the direct assignment of each antenna to a specific, single reader, and rely upon the health of that single reader for its operation.
- the practical implementation of large arrays of small antennas using only a small number of readers depends upon a robust, simple, and economical signal routing approach.
- each antenna can be accessed by any one of a collection of two or more readers, depending upon need.
- each antenna is assigned to a particular reader and can be accessed by no other reader in the network. If a reader fails or goes off line for any reason, all of the antennas assigned to that reader are essentially dead to the network.
- the only way to make it possible to access a particular antenna from more than one reader is to use complex combinations of multiplexers, separate control lines, and external switches.
- the current embodiments replace all of those components with a single device which allows multiple RPID readers access to the same set of antennas, thus providing the reader failover capability (i.e., a reader failure is detected by the host system managing the network, and is replaced by an active reader such that all antennas in the network remain accessible). Furthermore, a great advantage of the current embodiments over complex combinations of multiplexers, control lines, and external switches is that the current embodiments of the device can be controlled over the same lines that are used to carry the RFID traffic for communication with RFID tags. This greatly minimizes the cabling or wiring requirements for the network, providing lower cost, shorter installation times, easier maintenance, better aesthetics, smaller space requirements, and a number of other advantages.
- the current embodiments makes it practical to introduce redundant pathways in the network, allowing multiple readers to access a given antenna, it allows for network loading balancing. That is, the RFID network host system managing the readers can track the use of readers (load on readers) and use the switching capabilities of the device described in the current invention to spread the load evenly over the readers assigned to a given area of activity in the network.
- the present inventions relate generally to RFID network control devices, and methods of using the same.
- a RFID network control device that has a bypass capability between two control ports that are part of the RFID network control device, which allow for RFID traffic signals to enter and exit the RFID network control device using a bypass transmission path, without passing through other internal circuitry of the RFID network control device.
- RFID network control device that has a bypass capability between two control ports that are part of the RFID network control device, which allow for RFID traffic signals to enter and exit the RFID network control device using a bypass transmission path, without passing through other internal circuitry of the RFID network control device.
- the RFID network control device contains an active RFID reader, also referred to as a smart reader, and can thus generate and decode RFID control signals.
- FIG. 1 illustrates a prior art approach to antenna network control using a common RF cable for a large number of RFE) antennas, but a separate control line for each antenna activation relay;
- FIG. 2 illustrates an RFE) network control device (RNCD), in accordance with a preferred embodiment
- FIG. 3 shows an example of an antenna network enabled by the RFE) network control device (RNCD) according to a preferred embodiment.
- FIG. 4 shows details of the control port switching block (see 230 of FIG. 2), according to a preferred embodiment.
- FIG. 5 shows details of the control port selector and command interpretation block (see block 240 of FIG. T), according to a preferred embodiment.
- FIG. 6 shows details of the control port selector and command interpretation block (see 240 in FIG. 2), according to a preferred embodiment, showing the switch setting which allows commands from control port RF In B (sampled by line 220) to access the RFE) antenna port switch controllers (via lines 245a-245d).
- FIG. 7 shows details of the control port selector and command interpretation block (see 240 in FIG. T), according to a preferred embodiment, showing the switch setting which allows commands from control port RF In A (sampled by line 218) to access the RFE) antenna port switch controllers (via lines 245a- 245d).
- FIG. 8 shows details of the control port selector and command interpretation block (see 240 in FIG. 2), according to a preferred embodiment, showing the switch setting which allows commands from either RF In A (sampled by line 218) or RF In B (sampled by line 220) to access the RFID antenna port switch controllers (via lines 245a-245d).
- FIG. 9 shows details of the RFID antenna port switch controller block (see 250 in FIG. 2), according to a preferred embodiment.
- FIG. 10 shows details of the RFID antenna port switch tree block (see 270 in
- FIG. 2 according to a preferred embodiment.
- FIG. 11 shows the details of the network path analysis block 280, according to a preferred embodiment.
- FIG. 2 is a drawing showing the preferred embodiment of the RFID network control device (RNCD), using functional blocks to represent several parts of the device.
- RCD RFID network control device
- the device has two control ports 210 and 212, and also fourteen RFED antenna ports 290.
- Each of the RFED antenna ports 290 can be connected to an RFED antenna or other RFED-enabled input-output device (e.g., an RFID signal amplifier, a video display using the RFED protocol for part of its function, an electronic price display device, or a device to convert optical barcode scans into signals appropriate for the network's RFID protocol based communications).
- an RFID signal amplifier e.g., a video display using the RFED protocol for part of its function, an electronic price display device, or a device to convert optical barcode scans into signals appropriate for the network's RFID protocol based communications.
- FIG. 2 When used with a set of low cost RFED antennas built into or attached to the outside of retail shelving, the device shown in FIG. 2 enables an external RFED reader or functionally equivalent host system to access any of the antennas connected to ports 290.
- Either of the control ports 210 and 212 can be used for either input or output. Also, the presence of two control ports allows a network designer to place a number of these RNCDs in a series and communicate with any one of the devices along the chain from either end of the chain, providing valuable redundancy in the network.
- FIG. 3 shows an example of an RFED antenna network enabled by the RNCD.
- each of the network control devices 320, 330, and 340 are shown with fourteen antennas attached to the RFED antenna ports 290 (not labeled in the figure).
- the control ports 210 and 212 are clearly shown on each of the three network control devices. Note especially that the devices have not been connected in a careful manner so as to preserve the order of connection of these two ports. For example, in the case of device 320, port 210 has been connected to the Reader 1 side of the network, whereas port 212 has been connected to the Reader 2 side of the network.
- the connection is reversed. That is, for those two devices port 212 is on the Reader 1 side of the network and port 210 is on the Reader 2 side of the network.
- a fundamental property of the embodiments described herein is that one can connect the devices in any order using any of the control ports, and the network control devices (devices 320, 330, and 340 in FIG. 3) will allow the readers on the network to determine how the control ports have been connected, in a manner described elsewhere in this document. That is, the RFID network control device (RNCD) can support multiple independent readers in a bi-directional manner without respect to the order of the port connections. The internal features of the RNCD which make this bi-directionality possible will be described below.
- the simple network shown in FIG. 3 can be used to illustrate another important feature of the embodiments - the bypass feature.
- reader 310 in order for the first reader, reader 310, to access an antenna connected to RNCD 330, it must be able to send and receive signals along a path which runs through the intervening device - RNCD 320. This is accomplished by providing switching and control internal to the RNCD which provides a short (low-signal- loss) path inside the device, from one control port to the other control port.
- the means of providing this bypass path will be described in more detail below. Note that in order for a reader to access an antenna port on a given device, it must first identify the intervening devices and give instructions which place these devices in the bypass state.
- control units inside the various RNCDs in the network could be configured to act as routers which maintain a knowledge of the other devices on their branch or portion of the network and either disregard (discard) signals or pass along the signals (in the bypass state), depending on what other devices are connected, either directly or indirectly. That is, a novel feature, enabled by the bypass feature and the bi-directionality of the devices according to the preferred embodiments allows the device to act as a selective RFID signal router. This allows network architects to de-centralize the management of the RFBD network (i.e., spread the network management functions among a collection of network control devices rather than placing all of that burden on one or a small number of host systems attached to the network).
- the network example shown in FIG. 3 shows two readers which are directly coupled to RNCDs. It should be understood, however, that such readers as shown and described here are not typical RFID readers which one can buy on the open market. Rather these readers are multi-functional in that they can generate and decode RFID signals, according to an RFID air interface protocol, for communication with RFID tags (e.g., passive tags on items of interest), and the readers are also capable of generating and decoding commands which communicate with the RNCDs to govern their behavior. Such signals can be carried along the same cables as the RFID traffic, and be encoded as AM, FM, PSK, or any other encoding approach known to those skilled in the art. The control commands could also be incorporated as specific commands in the RFID air-interface protocol.
- the RFID reader is really a "smart reader" which is capable of managing a collection of RNCDs, assigning each one tasks as necessary, and configuring each as needed to create a path between itself and a particular antenna attached to a particular RNCD.
- a smart reader would, in turn, be attached to some host system or network running business applications or interfaces to other systems (not shown in FIG. 3).
- the preferred embodiments are not limited to applications involving smart readers as described above.
- the preferred embodiments also include network configurations and applications in which the smart reader is replaced by a system which includes a simple reader (one which only generates and decodes RFID signal traffic to and from tags), a host system (e.g., a computer or microcontroller-based unit) which interfaces with any outside network to which the RFBD network may be attached, and another device which manages the RFED network and has the capability to code and decode commands for control of the RNCDs.
- a simple reader one which only generates and decodes RFID signal traffic to and from tags
- a host system e.g., a computer or microcontroller-based unit
- another device which manages the RFED network and has the capability to code and decode commands for control of the RNCDs.
- the external network interface and RFED network management functions can be combined into a single unit having a single enclosure, such that the smart RFED reader is in the same enclosure as the RFID antenna ports, the two control ports, the switch network, and the control unit of one of the RNCDs. It is also within the scope of the present invention that the smart RFED reader is in close proximity, such as 10 to 100 feet, to the RFID antenna ports, the two control ports, the switch network, and the control unit of one of the RNCDs, such that there is minimal latency between signals transmitted between the smart reader in close proximity to the one RNCD in close proximity.
- RF input/output lines 214 (RF In A) and 216 (RF In B) receive or send RF signals by control ports 210 and 212, respectively, and pass these to and from the control port switching block 230.
- RFID traffic signals intended for an RFID antenna coupled to the device are being received through either of the control ports 210 and 212, one of these ports is selected by the control port switching block 230 and then sent out of the control port switching block via line 260 to the RFID antenna port switch tree block 270.
- the RFID antenna port switch tree block then sends the RF signal from line 260 to one of the RFID antenna ports 290.
- the function of block 240 is to sample the signals on lines 214 and 216 via lines 218 and 220, respectively, and use commands in those signals to set the state of the control port switching block 230 to one of three states: (1) RF In A active, (2) RF In B active, or (3) Bypass active.
- These command and control signals may be encoded either as RF signals modulated on the carrier wave, baseband shifts, or any other form of data encoding by amplitude, phase, frequency or other wave changes well understood by those skilled in the art.
- In the bypass state of the control port switching block 230 a direct communications pathway between the RF In A port and the RF In B port is made and any signal introduced at one port is passed out of the other port.
- this direct path passes RF but not DC (direct current) or very low frequency AC signals because of the capacitors used to isolate the switches as shown in FIG. 4.
- the bypass of the DC and low frequency AC signals (e.g., switch control and command signals) through the RNCD is accomplished through lines 218 and 220, as described in more detail below.
- a key function of block 240 is to pass control commands from lines 214 and/or 216 to the RFID antenna port switch controllers in block 250.
- the RFTD antenna port switch controllers then set the state of the RFID antenna port switch tree 270 via lines 255.
- FTG. 4 shows the details of the control port switching block 230, according to a preferred embodiment.
- the main components of this block include three single-pole double-throw switches 410, 420, and 430, and two inverting gates 450 and 470.
- Each of the double-throw switches is controlled by two inputs (labeled RFCl and RFC2 on each switch) such that, in this case, the switch state is set to the side corresponding to the higher of the two voltages (RFCl or RFC2).
- the position of the switch depends on the relative voltage levels of RFCl and RFC2, and in this preferred embodiment these relative voltage levels are controlled by the inverted and non-inverted control lines as shown in FIG. 4.
- the RFC2 input of switch 410 and the RFCl input of switch 420 will both be set high, and a pathway from line 214 (via switch 410) and line 216 (via switch 420) will be opened to switch 430.
- the setting of switch 430 (as determined by the voltage on line 235b) will then determine which of these lines (214 or 216) is open to line 260. In this way the voltage level on control lines 235a and 235b determine which of the two control ports (RF In A or RF In B) have access to the RFK) antenna port switch tree 270 and, ultimately, the RFID antenna ports 290.
- FIG. 5 shows the details of the control port selector and command interpretation block, 240, of the RFTD network control device (RNCD), according to a preferred embodiment.
- This block of components includes two switches 510 and 520, each of which is a dual SPDT (single-pole double-throw) switch.
- RF command interpreter subcircuits 540 and 550 which are capable of interpreting switch control commands in the signals (encoded as part of the RFID protocol, or a separate RF protocol, as baseband feature changes, or other data encoding methods) received into the block via lines 218 and 220.
- the interpreter subcircuits 540 and 550 were implemented with Maxim / Dallas Semiconductor "1-Wire" chips DS28E04S-100+ and DS2408S+, respectively, using baseband pulse amplitude/time signaling techniques. It should be recognized, however, that subcircuits 540 and 550 could be implemented with any combination of components which allows the extraction of switch setting commands from the baseband data signal. Examples of such circuits include those which make use of combinations of directional couplers, analog-digital converters, and microcontrollers which extract a small portion of the signal and convert that to a digital code corresponding to the required switch settings.
- interpreter subcircuit 550 is used to control the RFID antenna port switch controllers 250 (see FIG. 2) via control lines 245. Because the RNCD is bidirectional, it must be possible to set the switches in the RFID antenna port switch tree 270 using commands from either of the two control ports of the device. For example, it is an objective to allow the selection of any one of the fourteen antennas on any one of the three network control devices shown in FIG. 3 using commands from either of the two readers 310 or 350. With respect to FIG. 5 this bi-directionality requirement is equivalent to requiring that commands from either line 218 or 220 be routable to command interpreter subcircuit 550 since it is from that interpreter that the RFTD antenna port switch controllers receive their input. This requirement is satisfied using the two switches 510 and 520 in combination with the XOR gate 530.
- FIG. 6 shows the particular settings for switches 510 and 520 which direct the signal from line 218 (sampling RF In A as shown in FIG. 2) into interpreter subcircuit 540, and also the settings which direct the signal from line 220 (sampling RF In B as shown in FIG. 2) into interpreter subcircuit 550.
- the two pathways opened by the switch settings are shown by the bold lines in FIG. 6. In this state, it is the commands encoded in the signal from line 220 (RF In B) which are ultimately used to select the active antenna port (i.e., select one of the fourteen RFID antenna ports 290) via the RFID antenna port switch controllers 250.
- FIG. 7 differs from FIG. 6 in the setting of switch 520. In this case the signal from line 218 (RF In A) is directed to interpreter subcircuit 550 and thus determine the settings in the RFID antenna port switch tree.
- the first dual SPDT switch 510 is set such that no signals are running through it. In those two cases it is the second switch 520 that determines which of the two RF signals (i.e., signals from lines 218 and 220) are directed to the two subcircuits 540 and 550. However, as shown in FIG. 8, the first dual SPDT switch 510 can be put in a state which results in a connection to both subcircuits 540 and 550 from either end of the network (line 218 or 220). This provides very significant flexibility to the network operation. A crucial utility afforded by switch 510 when used as shown in FIG.
- these control commands if they are in the form of DC or low-frequency AC signals, cannot pass through the bypass route through switches 410 and 420 taken by the higher frequency RF signals as described previously.
- the DC and low-frequency AC signals rather, pass through switch 510 when it is configured as shown in FIG. 8.
- FIG. 6 shows that a reader or other RFTD-enabled device at either end of the network (via line 218 or 220) can change the state of dual SPDT switch 520 and thus change which end of the network is in control of the RFID antenna port switch controllers 250 and, through those, the state of the RFID antenna port switch tree 290.
- a reader at either end of the network which is not in contact with subcircuit 550 (and is therefore in contact with subcircuit 540) can issue a command to subcircuit 540 instructing it to flip its signal to the XOR gate 530 (1 to 0, or else 0 to 1) and thus change the state of dual SPDT 520.
- switches 510 and 520 and their use as shown in FIGS. 6, 7, and 8.
- the host When the network is first activated (Le., when the host system is turned on), the host must have some way of determining the identity, capabilities, and connectivity (port-to-port connections) of the RNCDs in the network. This is done as follows: First the network powers up with switches 510 and 520 configured as shown in FIG. 6. The host sends a search (identification) request to determine the identity of any and all microcontrollers on the network.
- each RNCD configured as shown in FIG. 6 (i.e., not allowing command bypass)
- only one microcontroller will be in a position to hear and respond to that ID request - either controller 540 or 550 of the RNCD closest to the host, depending on the setting of switch 520 in that RNCD, and also depending on the end of the network (i.e., port RF In A or RF In B) that connects that RNCD to the host.
- the host sends that microcontroller a signal to flip the state of switch 520.
- the other microcontroller of that first RNCD is exposed to the host and is authenticated and associated.
- the host issues a command to the second microcontroller of the first RNCD to flip the state of switch 510 so that the command signals from the host can reach the second RNCD in the network, at which time its two microcontrollers are authenticated and associated as before. This process is repeated for all RNCDs in the network.
- FIG. 9 shows the details of the RFID antenna port switch controller block 250, according to a preferred embodiment.
- This part of the RNCD in the preferred embodiment is composed of two conventional high-speed CMOS logic 3-to-8 line decoder modules 910 and 920.
- An example of such a decoder module available on the open market is the Texas Instruments CD74HC238M chip. Each of the two chips has 3 inputs (AO, Al, and A2) and 8 outputs (YO through Y7).
- Subcircuit 550 of the input switches control and command interpretation block 240 sets the inputs of the two decoder modules 910 and 920.
- FIG. 10 shows the details of the RFTD antenna port switch tree block 270 according to a preferred embodiment.
- the main signal line 260 coming from the control port switching block 230 enters the first layer switch 1010 of the RFE) antenna port switch tree.
- the setting of this first layer switch is controlled by the four control lines 255a, 255b, 255c, and 255d coming from module 910 of the RFID antenna port switch control block 250 (see FIG. 9).
- the truth table of the decoder module 910 is such that only one of the lines 255a, 255b, 255c, and 255d is high (logic 1) at any instant in time.
- the choice of the high line via its action on switch 1010, determines which of the second layer switches (1020, 1030, 1040, and 1050 in FIG. 10) will receive the RF signal from line 260 (see FIG. 10).
- the first four outputs YO, Yl, Y2, and Y3 from module 920 are used to control only three of the four second-layer switches (1020, 1030, and 1040 in FIG. 10).
- the last switch in the second layer, switch 1050 has its own dedicated control lines coming from decoder module 920 (lines 255i, 255j, 255k, and 2551).
- all four switches of the second layer would be controlled by the same four lines (e.g., 255e, 255f, 255g, and 255h).
- the last switch of the second layer (switch 1050) has been given its own control lines so that, when the network control device is in a bypass mode (i.e., none of the antenna ports 290 are being directly accessed), the first three switches of the second layer (switches 1020, 1030, and 1040) can be turned off.
- FIG. 11 shows the subcircuit used to analyze RF path and signal loss in a variable and unpredictable network environment.
- RNCD' s in the control of a large RFID antenna network, it is useful and convenient to use the RNCD' s for RFID path integrity analysis. For example, if a physical line disruption or break occurs somewhere in the network, the circuit of FIG. 1 1 can be used to indicate to the host system that the RNCD is on line and operating correctly.
- Input lines 275a and 275b come from the RFID antenna port switch tree 270 (see FIG. 10).
- control signal cntrl 1 acting on switch 1150.
- control signal cntrl 1 originates in control port selector and command interpretation block 240 (see FIG. 5).
- the host system can determine the health of the RF cables and connections between the RFID reader or host system and each RNCD in the network.
- the RFID network control device as described in the preferred embodiments enables the creation of single-cable RFID antenna networks of widely varying structure which have the desirable properties of reader failover, load balancing over the collection of readers in the network, decreased complexity of network design and installation, and other desirable characteristics of a robust plug-and-play RFID antenna network.
- the embodiments are of particular use in RFID applications with large numbers of small, low-power antennas, such as retail smart shelving applications.
- an RFID network control device comprising: a plurality of RFID antenna ports adapted to couple with RFID antennas and convey RFID traffic signals between said RFID network control device and one or more RFID tags in the vicinity of said antennas; at least two control ports, each of said control ports adapted to couple directly or indirectly to an RFID reader, and each of said control ports adapted to convey both RFID traffic signals for conveyance to said antennas, and also command signals for control of the operation of said RFID network control device, or other devices connected to said RFID network control device through its ports; a set of switches capable of connecting any one of said control ports to any one of said antenna ports of said RFID network control device; and a control unit or units such that, by appropriate command from any RFID reader attached directly or indirectly to any control port of said RFID network control device, said set of switches may be configured to direct RFID traffic from said RFID reader to any antenna port of said RFID network control device.
- the RFID network control device may further comprise a bypass pathway created by a switch or set of switches which can be configured to directly couple a pair of control ports of the at least two control ports such that RFID traffic signals and command signals may pass from one control port of said pair to the other control port of said pair.
- the control unit or units of said device can be instructed, configured, and controlled by commands from an appropriate reader coupled directly or indirectly to any control port of said device.
- the control unit or units of said device can be instructed, configured, and controlled by commands from a host system, computer, or external controller coupled directly or indirectly to any control port of said device, and wherein the RFED traffic signals used to communicate with RFEO tags in the vicinity of antennas coupled to said device are generated by an RFEO reader either located inside or coupled to said host system, computer, or external controller.
- the control unit or units of said device can be instructed, configured, and controlled by commands included as part of the RFID protocol signals generated and decoded by a reader coupled directly or indirectly to a control port of said device.
- the device can generate signals which can communicate with a second device coupled directly or indirectly to a control port of said device and thereby indicate to the second device the identity, configuration, settings, capabilities, and other characteristics of either itself or any other devices coupled directly or indirectly to control ports or RFED antenna ports of said device.
- Such a device can generate signals to instruct external devices coupled directly or indirectly to the control ports of said device regarding the identity of the control ports to which those external devices are coupled, and to subsequently respond to commands received from one of those external devices instructing the control unit or units to reconfigure a switch or set of switches in such a way that the identity of the control ports is effectively altered in a way which makes network management more convenient for one or more of the external devices.
- the host system, computer, or external controller has capabilities of RFED data filtering, smoothing, storage, aggregation, and/or analysis. Also, the host system, computer, or external controller can have capabilities of managing the RFED network control devices and other devices coupled to it, including the identification, capability assessment, connectivity and configuration state determination, active operating mode determination, duty cycle and load assessment, and assessment of other states, configurations, and capabilities necessary to initiate and maintain effective operation of the network.
- the RFED antenna network can comprising two or more
- RFID network control devices as described above, one or more RFID antennas coupled to one or more of the antenna ports of one or more of said RFID network control devices; two or more host systems, computers, or external controllers, each of which is coupled directly or indirectly to a control port of one or more of said RFID network control devices; two or more RFID readers, each of which is coupled to one of said host systems, computers, or external controllers; and cabling which couples all of the RFID network controllers into a network which allows any of said host systems, computers, or external controllers to create a communications pathway between any of said readers and any of said RFID antennas.
- the RFID network control devices mentioned above can form a linear chain or daisy chain, and in which one of said host systems, computers, or external controllers is coupled to an RFTD network control device on one end of said chain, and a second of said host systems, computers, or external controllers is coupled to an RFID network control device on the other end of said chain. They can also form a branching structure in which two or more of said RFTD network control devices form a linear chain, and the RFID network control device on one end of said chain is coupled to two or more additional RFID network control devices. Still further, the RFTD network control devices can form a loop or ring structure.
- the RFUD network control devices and the RFID antennas coupled to said RFID network control devices can be incorporated into the structure of a storage or display fixture such as a shelf, cabinet, counter, bin set, closet, or other fixture.
- a storage or display fixture such as a shelf, cabinet, counter, bin set, closet, or other fixture.
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Abstract
Description
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Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2008340208A AU2008340208B2 (en) | 2007-12-21 | 2008-12-22 | RFID network control and redundancy |
ES08865058.5T ES2536358T3 (en) | 2007-12-21 | 2008-12-22 | RFID network redundancy and control |
JP2010531343A JP5061245B2 (en) | 2007-12-21 | 2008-12-22 | Application related to RFID network control and redundancy |
EP08865058.5A EP2223469B1 (en) | 2007-12-21 | 2008-12-22 | Rfid network control and redundancy |
CA2700837A CA2700837C (en) | 2007-12-21 | 2008-12-22 | Rfid network control and redundancy |
HK11102038.7A HK1148395A1 (en) | 2007-12-21 | 2011-03-01 | Rfid network control and redundancy rfid |
Applications Claiming Priority (2)
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US1641307P | 2007-12-21 | 2007-12-21 | |
US61/016,413 | 2007-12-21 |
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WO2009082742A1 true WO2009082742A1 (en) | 2009-07-02 |
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PCT/US2008/088048 WO2009082742A1 (en) | 2007-12-21 | 2008-12-22 | Rfid network control and redundancy |
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EP (1) | EP2223469B1 (en) |
JP (1) | JP5061245B2 (en) |
AU (1) | AU2008340208B2 (en) |
CA (1) | CA2700837C (en) |
ES (1) | ES2536358T3 (en) |
HK (1) | HK1148395A1 (en) |
WO (1) | WO2009082742A1 (en) |
Cited By (1)
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US11213773B2 (en) | 2017-03-06 | 2022-01-04 | Cummins Filtration Ip, Inc. | Genuine filter recognition with filter monitoring system |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US11062099B1 (en) | 2019-10-31 | 2021-07-13 | United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | System and method for wearable, ubiquitous RFID-enabled sensing |
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-
2008
- 2008-12-22 CA CA2700837A patent/CA2700837C/en not_active Expired - Fee Related
- 2008-12-22 ES ES08865058.5T patent/ES2536358T3/en active Active
- 2008-12-22 EP EP08865058.5A patent/EP2223469B1/en not_active Not-in-force
- 2008-12-22 AU AU2008340208A patent/AU2008340208B2/en not_active Ceased
- 2008-12-22 JP JP2010531343A patent/JP5061245B2/en not_active Expired - Fee Related
- 2008-12-22 WO PCT/US2008/088048 patent/WO2009082742A1/en active Application Filing
-
2011
- 2011-03-01 HK HK11102038.7A patent/HK1148395A1/en not_active IP Right Cessation
Patent Citations (5)
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US20050157699A1 (en) * | 2004-01-21 | 2005-07-21 | Sharp Kabushiki Kaisha | Data communications device, data communications system, data communications method, data communications computer program, and computer-readable storage medium containing computer program |
US20070053309A1 (en) * | 2005-09-06 | 2007-03-08 | Texas Instruments Incorporated | Policy-Based Topology Maintenance for Wireless Networks that Employ Hybrid Tree-Based Routing with AODV |
US20070206705A1 (en) * | 2006-03-03 | 2007-09-06 | Applied Wireless Identification Group, Inc. | RFID reader with adjustable filtering and adaptive backscatter processing |
WO2007103445A2 (en) | 2006-03-07 | 2007-09-13 | Vue Technology, Inc. | Network control |
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US11213773B2 (en) | 2017-03-06 | 2022-01-04 | Cummins Filtration Ip, Inc. | Genuine filter recognition with filter monitoring system |
Also Published As
Publication number | Publication date |
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EP2223469A1 (en) | 2010-09-01 |
HK1148395A1 (en) | 2011-09-02 |
JP5061245B2 (en) | 2012-10-31 |
AU2008340208A1 (en) | 2009-07-02 |
ES2536358T3 (en) | 2015-05-22 |
EP2223469B1 (en) | 2015-02-18 |
EP2223469A4 (en) | 2011-05-25 |
CA2700837C (en) | 2017-07-18 |
CA2700837A1 (en) | 2009-07-02 |
JP2011501329A (en) | 2011-01-06 |
AU2008340208B2 (en) | 2013-07-11 |
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