Abstract:
The invention is directed to encoding information in radio frequency identifier (RFID) tags disposed on cabling interconnects for the purpose of easier identification of the cables, especially when ascertaining the physical routing and connectivity of the cables. The encoding can be performed before, during, or after installation of the cable. The encoded information can then be read at any time using an RFID reader, for example to identify the cable at various positions along it, thereby enabling easy determination of the routing of the cable.

Description:
FIELD OF THE INVENTION 
     The invention is directed to systems, or subsystems, interconnected by a plurality of cables, also referred to herein as cabling interconnects, and to the use of radio frequency identifier (RFID) technology for identifying such cables. 
     BACKGROUND OF THE INVENTION 
     Evolution of network technologies resulted in a world of interconnected networks where businesses and households are now amazingly close to each-other. The notion of “network” turns out to be central to our times: the Internet, LANs, WANs, enterprise networks, home networks, etc. are today interconnected over the World Wide Web, changing our lives and the way we do business. This evolution presents significant challenges to service and network providers, which attempt to serve their clients faster and better, by continuously enlarging and upgrading their networks with a view to serve a growing number of clients and to implement the latest advances in networking technologies. 
     Typically, the equipment is situated in an environmentally hardened enclosure, such as a cabinet, or in a central office (CO) or a point-of-presence office which is generally environmentally controlled. Because the cost of space in these environments is high, the equipment is commonly organized in the most compact manner that is practical. As a result, there is often a confusing collection of cabling running through the environment to interconnect the equipment within the respective location (office, cabinet, etc) both to other equipment within the location and to equipment outside of the location. 
     Network deployment and upgrading presents complex challenges to providers, one of which is managing interconnections between equipment of various size, make and functionality (also referred to here as systems) that make-up the network. 
     Thus, techniques to ascertain the existing physical cabling connections between various systems within a certain location (e.g. a Central Office) are needed. These techniques would also apply to cabling connections of electronic systems in general, in situations where there are numerous systems to be interconnected at a particular installation site and there are a very large number of electrical or optical cables interconnecting them, such that there exists a very real possibility of incorrect connections and wherein determining the exact nature of the interconnection errors would be a very onerous and time consuming task. In addition, these techniques should be equally applicable to cables made of optical fiber or copper. 
     It is known to attach identifying tags to cabling; this may be as simple as attaching a paper tag with a tie-wrap or writing on a piece of tape that is adhered to the cable. However, physical tags may become separated from the cables and the labels may be rendered illegible. Further, locating a particular tag amongst a great many tagged cables in a crowded environment may be difficult. 
     It is also known to use unique connectors. The connectors may be affixed to multiple cables and have a geometry that allows insertion into only one type of device in one particular way. However, the connectors must be connected to the cables in the proper way. Further, designing and manufacturing unique connectors for a very large number of cables is difficult and relatively costly because each can only serve a particular function and production runs tend to be in relatively small numbers. 
     RFID technology, although nascent, is known for improving supply chain efficiency by facilitating tracking of goods. For example, RFID may displace the bar codes currently used to identify products. An RFID tag includes an antenna and a small, inexpensive circuitry chip which stores data such as a product&#39;s expiration date and Electronic Product Code (EPC). The circuitry is responsive to a particular RF signal transmitted by a reader to generate a corresponding signal including the stored data. The range of the corresponding signal is dependent on various factors, but may be effective up to ten meters. 
     For example, Hewlett Packard and Connectivity Technologies offer solutions in this area, particularly using RFID tags at the ends of cables and RFID readers at the input/output (I/O) interfaces of systems interconnected by the cables to read the tags, thereby identifying which endpoint of cables are connected to which I/O interfaces. The cable identification information is then sent to an Operation Support System (OSS) or Network Management System (NMS) that uses the information to determine the interconnection of the systems, which is made available to an operator, e.g. as a network map. However, this solution does not determine the physical layout of the cabling, which can be important for repairing or replacing faulty cables or to locate cables for various reasons, e.g. system relocation, site construction/maintenance, etc. 
     A system for locating the geographical position of network elements in a network has also been proposed, as described in the US patent application publication number 20030109267 (Bulut) filed on Jun. 12, 2003 and entitled “Network element locating system”. This patent application describes equipping network equipment with locators and connecting into the network a position manager. The locators acquire location information for the respective equipment and store it as position data. The equipment transmits the position data to the position manager over the network on request, and the position manager provides the user with the location of the equipment. However, this solution is mostly concerned with locating the equipment in case of faults and does not address the problem of determining the physical layout of the cabling. 
     Therefore, it would be desirable to have a solution to determine the physical routing of cables interconnecting communications systems for various purposes including repair or replacement of faulty cables, relocation of the communications systems, and maintenance or reconstruction of the immediate environment of the cables or the communication systems. 
     SUMMARY OF THE INVENTION 
     The invention is directed to encoding information in radio frequency identifier (RFID) tags disposed on cabling interconnects for the purpose of easier identification of the cables, especially when ascertaining the physical routing and connectivity of the cables. 
     Embodiments of the invention enable easy and efficient writing, or encoding, of identification information into RFID tags disposed along a cable interconnecting systems or subsystems. The encoding can be performed before, during, or after installation of the cable. The encoded information can then be read at any time using an RFID reader, for example to identify the cable at various positions along it, thereby enabling easy determination of the routing of the cable. 
     According to an aspect of the invention there is provided an RFID encoder for encoding information on RFID tags disposed on a cable. The RFID encoder includes an RFID interface for interfacing with the RFID tags; a controller operable to control the RFID interface to accomplish encoding of the information on the RFID tags; and a guide for positioning the cable in a correct position for encoding a selected on RFID tag. 
     In some embodiments of the invention, the guide includes one or both of two cable guides and a proximity detector. Each of the cable guides is situated on the RFID encoder such that both cable guides align with the longitudinal axis of the cable when the cable is positioned in both of the cable guides. The cable guides help hold the cable in correct alignment with the RFID encoder during an encoding operation. The proximity detector is for determining whether or not the selected RFID tag is within a range of positions for successful encoding of that RFID tag. 
     According to another aspect of the invention there is provided a method of encoding RFID tags disposed on a cable. The method includes the steps of positioning the cable in a first position with respect to an RFID encoder for encoding a first RFID tag of the RFID tags, and encoding a cable identifier into the first RFID tag. 
     According to yet another aspect of the invention there is provided a cable comprising a plurality of RFID tags disposed at approximately equal intervals along its length. 
     According to still another aspect of the invention there is provided a cable bundle comprising a plurality of cables held in close proximity to each other along their longitudinal axis by sheathing and a plurality of RFID tags disposed at approximately equal intervals along the sheathing. 
     Advantageously, embodiments of the invention could be used by network and service providers to troubleshoot cabling interconnection problems of communications equipment, both electrical and optical interconnections, as well as other types of electronic systems in general. Important reductions in the time needed to troubleshoot cablings errors may be obtained by addressing the problem of easily and accurately determining the physical routing of cables, e.g. of interconnection systems in a Telco&#39;s CO, Enterprise&#39;s datacenters or other cabling applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiments, as illustrated in the appended drawings, where: 
         FIG. 1  illustrates an RFID encoder according to an embodiment of the invention; 
         FIG. 2  is a functional block diagram of the RFID encoder of  FIG. 1 ; 
         FIG. 3  shows the format of information stored in the RFID tags of  FIG. 1 ; and 
         FIG. 4  illustrates an RFID encoder according to an embodiment that uses a cable bundle. 
     
    
    
     In the figures like features are denoted by like reference characters. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a cable  10  is equipped with multiple RFID tags  12 ,  14  disposed at approximately equal intervals along its length. The RFID tags  12 ,  14  each have an antenna that aligns lengthwise with the longitudinal axis of the cable  10 . The RFID tags  12 ,  14  are drawn in dotted line to denote that they are on the backside of the cable  10  with respect to the point of reference of the viewer. An RFID encoder  16  is shown behind the cable  10  in a position to read or write to the RFID tag  12 . 
     The RFID encoder  16  includes proximity sensors  18 ,  20  on a face adjacent to the cable  10 . The proximity sensors are used when an RFID tag  12  is being encoded by the RFID encoder  16  to verify that the RFID tag  12  is in a correct position for the encoding operation. The RFID encoder  16  also includes cable guides  19 ,  21  protruding from the face at either end of the RFID encoder  16  and situated such they align with the longitudinal axis of the cable  10 , thereby enabling the cable  10  to pass through the cable guides  19 ,  21  during write and read operations of RFID tags disposed on the cable  10 . Each of the cable guides  19 ,  21  is shown as surrounding the cable  10  against the face of the RFID encoder  16 ; however each cable guide could alternatively be a pair of prongs through which the cable  10  passes. Each cable guide  19 ,  21  could be fixed such the cable must be passed through it, or it could open, e.g. being pivoted at one end, to allow the cable to be inserted therein, and then be closed around the cable  10 . The cable guides  19 ,  21  may be adjustable to accept various sizes of cables while keeping the cable  10  in the correct position for the encoding operation. 
     The RFID encoder  16  also includes a coupling device  22  used in interfacing with the RFID tags  12 ,  14 . The coupling device  22  would typically be an RF antenna for transmitting RF signals to, and receiving RF signals from, the RFID tags  12 ,  14 . However, other ways of interfacing with RFID tags  12 ,  14  are known, for example using capacitive coupling to encode RFID tags  12 ,  14 . In that case the coupling device  22  would be a specifically formed capacitive plate or grid. 
     The RFID encoder  16  is portable and has a physical structure adapted for handheld operation by a user. That is, the physical structure of the RFID encoder  16  is of a size and weight that allows for easy handheld operation and includes a feature such as a handle that enables a user to easily grasp the RFID encoder in one hand. 
     Referring to  FIG. 2 , the RFID encoder  16  includes several functions which are depicted as functional blocks in this diagram. The RFID encoder  16  includes a controller  24  that preferably comprises a central processing unit (CPU) and memory in which a control program is stored and is executed by the CPU to communicate with, and control as necessary, other functional blocks to carry out operations such encoding and reading RFID tags  12 ,  14  as well as other functions, which will be explained later. The controller  24  also has the capability, via the aforementioned memory or another memory, to store data that will be written to, and data that has been read from, the RFID tags  12 ,  14 . The controller  24  is coupled to an RFID interface (I/F)  26 , which is used for physically interfacing with the RFID tags  12 ,  14 , for example by RF signals or capacitive coupling. The RFID interface  26  includes the previously mentioned coupling device  22  and associated electronics for generating the necessary electrical signals to drive it under the control of the controller  24 . For example, in the case of RF coupling the coupling device  22  would be an RF antenna and the associated electronics would be an RF transmitter and receiver, or transceiver, which operate under the control of the controller  24 . 
     The RFID encoder  16  also includes a proximity detector  28  for determining the position of the cable  16  and RFID tags  12 ,  14  with respect to the RFID encoder  16 . The proximity detector  28  includes the proximity sensors  18 ,  20  and associated electronics necessary to interface with the controller  24 , to which it is coupled. The proximity detector  28  provides a positive verification signal to the controller  24 , indicating that an RFID tag  12  is in a correct position for performing an encoding operation on the RFID tag, both before and during the encoding operation. The correct position could actually fall within a range of positions for successful encoding of the RFID tag  12 . If the RFID tag  12  being encoded moves outside this range of positions during the encoding operation the positive verification signal would be de-asserted, which would be indicated to a user. The proximity detector  28  can operate autonomously, or perform a proximity determination on request by the controller  24 , for example before an encoding operation is initiated. The proximity detector  28  can also trigger an encoding operation via positive verification signal when an RFID tag  12  is detected as being in the correct position for performing an encoding operation. For example, this would be useful when the RFID encoder  16  is in a sequential write mode in which the RFID encoder  16  is quickly passed over a length of cable and RFID tag  12  disposed thereon are sequentially encoded automatically as each moves into the correct position for encoding. 
     The RFID encoder  16  also includes a user interface  30  coupled to the controller  24 . The user interface  30  includes a display and a keypad for communicating information to and from a user, respectively. Alternatively, or additionally, the display could be of the touch screen type for receiving user input. Information communicated to the user includes information read from RFID tags embedded in or affixed to the cable  10 . Information communicated to the RFID encoder  16  from the user includes information to be written to the RFID tags. Examples of both types of information will be given later with reference to  FIG. 3 . The user interface  30  also provides the user with a capability to initiate RFID tag read and write operations and provides indications associated therewith as previously described, as well as providing an interface to change the operational mode of the RFID encoder  16 . 
     The RFID encoder  16  also includes a communications interface  32  coupled to the controller  24 . The communications interface  32  includes ports for wired communications, such as a serial and parallel port, as well capabilities for wireless communications, such as a transceiver and an antenna, e.g. for Wi-Fi or Bluetooth communications. The communications interface  32  also includes electronics associated with serial and parallel ports such as physical layer drivers, receivers, and buffers. Specialized devices for implementing one or more communication protocols may be included in the communications interface  32 . Alternatively, implementation of one or more of these protocols could be accomplished by software executed by the controller  24 . The communications capabilities provided by the communications interface  32  are useful for communicating information between the RFID encoder  16  and another system such as a network node or management system, e.g. an operation support system (OSS) or network management system. In particular, such information would include information read from, or to be written to an RFID tag  12  such as a cable identifier and a network identifier. 
     The RFID encoder  16  also includes a global positioning system (GPS) receiver  34  coupled to the controller  24 . The GPS receiver  34  is operable to receive GPS signals which indicate the global position of the GPS receiver  34 . This global position can be encoded in the RFID tag  12  for purpose of accurately locating the cable  10  on which the RFID tag  12  is disposed when the contents of the RFID tag  12  is read. Alternatively to encoding the global position on the RFID tag  12 , the global position could be associated with identifiers read from the RFID tag  12 , e.g. a cable identifier and a tag identifier, and transmitted to a management system for recording the physical routing of the cable  10 . 
     With reference to  FIG. 3 , the format and contents of information encoded on the RFID tags  12 ,  14  will now be described. This encoded information includes a cable identifier  36 , a tag identifier  38 , a location identifier  40 , and optional additional information  42 . The cable identifier  36  is preferably unique to the premises at which the cable  10  is installed. The cable identifier  36  could be assigned at the time of encoding the RFID tags  12 ,  14  before or during installation of the cable  10 , or it could be downloaded from a network node or management system via the communications interface  32  during or after installation of the cable  10 . The tag identifier  38  uniquely identifies the RFID tag  12 ,  14  onto which it is encoded with respect to at least the cable  10  on which the RFID tag  12 ,  14  is disposed. For example, the tag identifier  38  could be a sequence number that is local to the cable  10  or it could be a distance of the RFID tag  12 ,  14  with respect to one end of the cable  10 . The location identifier  40  provides positional information of the RFID tag  12 ,  14 . For example, the location identifier  40  could be a global position obtained via the GPS receiver  34  or positional information with respect the premises at which the cable  10  is installed (e.g. building E floor  2 ; pillar  2 A; conduit  15 ). The optional additional information  42  includes information such as a network identifier, a network operator identifier, or a customer identifier. 
     The RFID tags  12 ,  14  are preferably re-writeable or one-time programmable (OTP) passive RFID tags  12 ,  14  typically belonging to EPC types class 0+ or class 1 high frequency (HF), or class 1 ultrahigh frequency (UHF) generation 2 (GEN2) depending on the application. The HF RFID tags  12 ,  14  operate at 13 MHz and have a read range of about 3 feet, while the UHF RFID tags  12 ,  14  operate at 900 MHz and have a read range of 3 to 10 feet or more. In some applications, the smaller range and better penetration of the HF RFID tags  12 ,  14  may be more desirable than the UHF RFID tags  12 ,  14 , for example in installations having a very large number of collocated cables. If an EPC code is to be used in the RFID tags  12 ,  14 , which code is typically 96 bits in length, the GEN2 tags  12 ,  14  should be used because they have an extra 160 bits of memory for storing additional information. Passive RFID tags  12 ,  14  with up to 1 kilobyte of non-volatile memory are currently available. Preferably, the RFID tags  12 ,  14  would be under the sheathing of the cable. 
     Numerous modifications, variations and adaptations may be made to the embodiment of the invention described above without departing from the scope of the invention, which is defined in the claims. 
     An example of a variation of the RFID tags  12 ,  14 , which in the described embodiment are disposed such that the antenna of each RFD tag  12  is aligned with the longitudinal axis of the cable or cable bundle  10 , as depicted in  FIG. 4 , would to position one or more RFID tags  12 ,  14  such that the antenna of each either fully or partially encircles the cable or cable bundle  10  transversely to said longitudinal axis or even in a helical manner. Further, one or more of the RFID tags  12 ,  14  may have multiple antennas, wherein each antenna of a given RFID tag  12  has a different orientation with respect to other antenna of the same RFID tag  12 . This arrangement could be implemented for better transmission from and reception by the given RFID tag  12 . 
     Other variations to how RFID tags  12 ,  14  are disposed on a cable  10  besides the described technique of embedding the RFID tags  12 ,  14  beneath cable sheathing include affixing the RFID tags  12 ,  14  to the outside of the cable  10 . Furthermore, embedding the RFID tags  12 ,  14  beneath the cable sheathing should be understood to include affixing the RFID tags  12 ,  14  to a particular conductor or fiber of the cable  10 , over which the sheathing is applied. The same principles of disposing the RFID tags  12 ,  14  with respect to cables and conductors or fibers therein as well as cable sheathing apply equally to cable bundles  10  and their cables and sheathing. Furthermore, in cases where an RFID tag  12  is embedded beneath cable sheathing, a marking on the sheathing that indicates the location of the RFID tag  12 , e.g. directly opposite the RFID tag  12  on the outside of the sheathing, could be advantageous. 
     An example of a modification to the information stored in the RFID tags  12 ,  14  would be to encrypt all or part of the information to be encoded on a given RFID tag  12  and then to encode that RFID tag  12  with the encrypted information. This encryption could be performed by the controller  24  executing a software program for performing the encryption, or the encrypted information could be received by the RFID encoder  16  via the communication interface  32 . In some applications, the additional security provided by such a technique could be desirable, depending on the information being written to the RFID tag  12  and security vulnerabilities present at the premises at which the cable or cable bundle  10  is installed. A variation of the information stored on RFID tags  12 ,  14  would be to store a pointer to all or part of the information. This would be useful in cases where the memory storage space on an RFID tag  12  is too-small to contain all the desired information. The pointer could be used as a database index into an external system that stores more detailed information. For example: ABCD12345678 could index into “Cable 123511B, Conduit XYZ from LAX to DEN, Installed 813104, Tested Aug. 4, 2004, Cable Path: LAX—Palm Springs—Phoenix—Colorado Springs—DEN”. 
     An example adaptation could be made to the use of the RFID encoder  16  when operating in the aforementioned sequential write mode. In this scenario a cable manufacturer may pre-encode the RFID tags  12 ,  14  of an entire spool of cable  10 . For example, the encoded information on a given RFID tag  12  could be a unique manufacturer ID instead of the cable identifier  36  and the tag identifier  38  could represent a distance from one end of the cable  10 , the latter being as previously described. In this case it would be advantageous to have the RFID encoder  16  control a cable feeder that advances the cable  10  after each RFID tag  12  is successfully encoded. In this application the aforementioned positive verification signal could be communicated to the cable feeder via the communications interface  32  to control advancement of the cable  10 . Alternatively, or additionally, the RFID encoder  16  could read back information just encoded on an RFID tag  12  and to verify that the information was successfully encoded; and responsive verification of such success, provide a signal to the cable feeder via the communications interface  32  to initiate advancement of the cable  10  to the next RFID tag  12  to be encoded.