Abstract:
A network enables remote users to communicate with, and to control a variety of devices whose only electrical connection is to a power line network. In hybrid networks, communications between different network domains is only available if proper message mapping is done. Message mapping leads to the determination of correct frame conversion based on the specifications of protocols identifying different networks. This invention comprises a method that does bi-directional conversion between application level information entered into the remote access device by the user and related physical layer power line communications frames.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates generally to devices connected to AC power lines, and more particularly to communication information between wireless telephone devices, Internet devices, and home appliances.  
         BACKGROUND OF THE INVENTION  
         [0002]    There is a great interest in communicating information with devices connected to AC power lines. More particularly, users would like to control and sense home appliances remotely. Currently, it is possible to transmit and receive computer, television, and telephone signals on AC power lines. In the future, users would also like to be able to monitor and control thermostats, refrigerators, stoves, lighting fixtures, heating and cooling systems, and the like, while away from their homes.  
           [0003]    In such arrangements, one or more appliances, e.g., PCs, televisions, telephones, stereos, would be connected to the AC power line for receiving power, and a power line communication (PLC) adapter could be used for receiving and transmitting the information signals. The PLC adapter can be embedded in the appliances to extract information signals from the AC power line.  
           [0004]    Most prior art literature describing power line communication networks has mainly been concerned with the physical layer specification of power line communication (PLC) protocols. For example, the art has focused on modulators, demodulators, converters, filters, signal detectors, synchronizers, and the like.  
           [0005]    In addition, most prior art systems only permit communication between like devices, or communicating to a specific class of devices, for example, only between telephone, only between audio monitors, only to NTSC type devices, and so forth.  
           [0006]    U.S. Pat. No. 5,777,545 “Remote control apparatus for power line communications system,” issued to Patel, et al. on Jul. 7, 1998, describes a remote control device for a power line communications system that uses pulse code modulation.  
           [0007]    U.S. Pat. No. 5,805,053 “Appliance adapted for power line communications,” issued to Patel, et al on Sep. 8, 1998, describes electrical appliances receiving and transmitting information to each other over a power line. The arrangement uses a transformer, bandpass filter, and amplifier and shaper.  
           [0008]    U.S. Pat. No. 6,084,758 “Power distribution system with circuit breakers remotely resettable by signals transmitted over the power lines,” issued to Clarey et al. on Jul. 4, 2000, describes a power distribution system where circuit breakers at a load center are remotely reset by reclosers using a power line communication system, such as an X10 or CEBus system. A remote master unit, which generates reset signals, is connected to an unaffected branch circuit, preferably by plugging into an accessible location remote from the affected load center. The reclosers may be addressed individually or globally by the master unit.  
           [0009]    U.S. Pat. No. 6,218,931, “Home-appliance network with nodes identified by direct-sequence spreading codes,” issued to Asghar et al. on Apr. 17, 2001, describes a network interface that couples residential appliances into a code-division multiple access (CDMA) network to convey appliance control and status signals. A spreading-code generator generates the codes, and a spread mixer modulates a narrowband transmit signal with the spreading code that is then coupled into the physical medium of the network.  
           [0010]    U.S. Pat. No. 6,246,868 “Conversion and distribution of incoming wireless telephone signals using the power line,” issued to Bullock et al., on Jun. 12, 2001 describes a system where wireless signals are received, converted, and distributed over AC power lines to one or more telephone communication devices within a building, office or complex is disclosed. That system provides for the reception of PCS, cellular and/or satellite communication signals, and provides an interface to standard generally available telephone equipment. By making use of a power line carrier channel, telephone equipment located remote from standard telephone wiring can be accessed. Moreover, by distributing such received wireless signals over the power line a number of telephone devices can be used to receive the distributed signals. In addition, the system allows previously installed telephones to communicate over and with wireless communication devices. As a limitation, that system is only concerned with distributing telephony signals, and does not address the general problem of controlling and communicating with a variety of non-telephonic home appliances, and the problem of acquiring status information about the appliances.  
           [0011]    U.S. Pat. No. 6,288,632 “Apparatus and method for power line communication (PLC),” issued to Hoctor, et al. on Sep. 11, 2001, provides a transmitter that broadcasts a signal for communicating information over a power line. The signal includes a superset, and the superset includes tone sets. Specifically, the signals of the tone sets are characterized by a spectral shape exhibiting main lobes within a harmonic interval. There is a main lobe for each different tone set.  
           [0012]    Recently, IBM has described a software toolkit called the Service Management Framework™, which is designed to be fully compliant with the OSGI (Open Service Gateway Initiative). The OSGI specification is an open industry standard for connecting “smart devices” to the Internet, including everything from home appliances and set-top boxes to game machines and medical devices. Thus, the connected devices can be operated remotely. Unfortunately, that tool kit does not address the general problem of devices that only have a connection with a power line.  
           [0013]    Therefore, there is a need for a system, method and network that enables remote users to communicate with and to control a variety of devices whose only electrical connection is to a power line network.  
         SUMMARY OF THE INVENTION  
         [0014]    A network enables remote users to communicate with, and to control a variety of devices whose only electrical connection is to a power line network. In hybrid networks, communication between different network domains is only available if proper message mapping is done. Message mapping leads to the determination of correct frame conversion based on the specifications of protocols identifying different networks. This invention comprises a method that does bi-directional conversion between application level information entered into the remote access device by the user and related physical layer power line communications frames.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a block diagram of a home appliance network according to the invention;  
         [0016]    [0016]FIG. 2 is a block diagram of an application layer power line communication frame according to the invention; and  
         [0017]    [0017]FIG. 3 is a block diagram of conversion between application layer powerline communication frames and physical layer power line network frames according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    Network Architecture  
         [0019]    [0019]FIG. 1 shows a home appliance network  100  according to the invention. The primary purpose of the network  100  is to allow users to control and exchange information with home appliances using remote access devices. A power line communication interface (PLCI)  120  integrates at least two distinct and different sub-networks that comprise the home appliance network  100  according to the invention: a local AC power line network (PLN)  103  with a telephone communication network  101 , or the local AC power line network  103  with a wide area heterogeneous communication network  102 , e.g., the Internet.  
         [0020]    The telephone network  101  can include plain old telephone services (POTS) as well as remote access devices  111 , e.g., cellular telephones. The structure and operation of the Internet  102  is well known. It is understood that the Internet can be accessed on a worldwide basis. The AC power line network (PLN)  103  for a home  104  is also well understood. Home appliances  131 - 134  are connected to the PLN  103 .  
         [0021]    Hereinafter, the term “home appliance” is used broadly to mean any power line communication device (PLCD) that connects to the AC PLN  103  and includes a device adapter  140 . The device adapter  140  is configured to receive  141  and transmit  142  information on the PLN  103  using PLN frames, described in greater detail below. As a characteristic of the invention, the only electrical connection required for the PLCDs is a connection to the PLN  103 , although it should be understood that some devices, such as televisions, may also have other connections, e.g., a cable TV network connection, however the present invention is not concerned with such other electrical connections.  
         [0022]    The PLCI  120  includes a power line network adapter (PLNA)  126 , and a tone-to-power line communication (PLC) frame mapping unit (TMU)  122  and a presentation page server (PPS)  124 . The system also includes a power line communication adapter PLCA  128  with a graphical user interface  129  and external programming functionalities to be accessed by the user at home.  
         [0023]    As shown in FIG. 1, all network elements are connected via the PLCA  128 . The PLCI  120  performs as a network bridge between the TMU  122  and the PLNA  126 , and between the PPS  124  and the PLNA  126 . The PLCA  128  can also perform the same functions as the remote access device  111 , and therefore includes the I/O interface  129 . For example, the user of the system  100  can set and sense appliances properties while in the home  104 .  
         [0024]    Power Line Communication Frames  
         [0025]    The TMU  122  converts between tone frequencies and voice commands entered into the remote access device  111  by the user and PLC frames  200  as shown in FIGS. 2 and 3. The PLC frames are independent of the physical characteristics of the PLN  103 , and therefore can be considered to compatible with an application layer of the network  100 . The PLNA  128  can map PLC frames  200  to PLN frames  310  described below. The PLN frames are dependent on the physical layer of the PLN  103 .  
         [0026]    Each application layer PLC frame  200  according to the invention includes an authentication code field  201  as described below, this can be an ESN, or a personal user identification. In an action field  210 , PLC frames are classified into two types: frames that read device values from a PLC device connected to the network  103 , and frames that write values to a PLC device within the network  103 . For example, the entry of “1” on a phone keypad is mapped to “read” actions  211 , and the entry “2” is mapped to “write” actions  212 .  
         [0027]    A device ID field (Z)  220  selects a specific one of the home appliances  131 - 134  connected to the PLC network  103 . Each class of the PLC devices  131 - 134 , lamps, televisions, climate controller, security device, etc, has a set of associated properties such as, on/off status, thermostat settings, timer settings, etc. The home  104  may have several instances of the same PLC device, for example microwave ovens, at several locations. Therefore, for control of such devices independently from one another, a location ID (P) can be entered in field  230 . The object property field (Q)  240  specifies the specific device property to be read or written, and the property value field (R)  250  contains the value to be read or written, for example 78 (degrees).  
         [0028]    Power Line Network Frames  
         [0029]    As shown in FIG. 3, the PLCA  128  converts PLC frames  200  to PLN frames  310 . Each read or write action is inserted in a service code field (SC)  311  of the PLN frame  310 . The PLN frame  300  also includes a source ID  312 , a destination ID  313 , a byte counter (BC)  314 , an object property code (OPC)  315 , and the value (Payload)  316  to write to the device if the action is a write action. Depending on the action and data value to write or read, frame sizes may change, hence the byte count field  314 . The FCC  317  field provides a forward error correction code. PLNA  126  broadcasts the PLN frame on the PLN  103 , and waits for a response from a related one of the PLCDs  131 - 134 . If the PLCI  120  does not include a PLCA  128 , the frame conversion functionality  300  can be performed by the TMU  122  and/or the PLNA  126 . If the communication is via the Internet  102 , the frame conversion functionality  300  can be done by the PPS  124  and/or the PLNA  126 , or entirely completed within the PPS  124 . It is also possible to move the functionalities of TMU and PPS into the remote access device  111 . In such a case, with proper selections from a menu available on the remote access device  111 , the frame is generated and converted to the PLN  310  frame on the remote access device  111 , and then the PLN frame is sent to the PLNA  126 .  
         [0030]    Network Protocols  
         [0031]    The telephone network  101  can use any standard protocols including dual tone multi-frequency (DTMF) signals (touch tones) for signaling purposes, and CDMA for a carrier protocol on channel  112 . The line  114  between the PLNA  126  and the PLCA  128  can use RS-232 or infrared signaling. The protocol on lines  132  uses a power line communication protocol (PLCP), described in greater detail below.  
         [0032]    In the PLCP, the PLNA  126  sends the frame  310  to the PLN  103 , and waits for a response and a result from the device  131 - 134  the frame is sent to. The response information is an acknowledgment (ACK) packet that is sent back to the PLNA  126  from the PLC device. If PLNA does not receive an ACK packet from the PLC device  131 - 134  within a specified time interval, e.g., several milliseconds, it is considered to be non-acknowledgment. It may be necessary to send the same frame several times to the PLC device from PLNA, or until an ACK is received from the device. After the ACK packet, the PLC device sends a second frame that is the “result frame.” The “result frame” includes a value returned by the “read from” action.  
         [0033]    Network Operation  
         [0034]    During operation of the network  100 , users can exchange data with the home appliances  131 - 134 . The exchanged data can include status information, appliance settings, and commands. Status and settings information can include, for example, temperature readings, and thermostat setting. Other status information can include on/off status and timer information, and the commands to turn specific appliances on and off, initiate recording functions, and the like.  
         [0035]    User Authentication  
         [0036]    The user can initiate operations by calling a home telephone number associated with the PLCI  120 . A connection is only established when a user authentication is successful. In a mobile telephone network, user authentication relates to a set of functions used to prevent fraudulent access to the network  101  by phones illegally programmed with counterfeit mobile identification (MIN) and electronic serial number (ESN) information. A successful outcome of authentication occurs when it can be demonstrated that the mobile phone  111  and the network  101  possess identical results of an independent calculation performed in both the cell phone and the network  101 . If the remote access device  111  is not a cellular phone, authentication can be based on logging in with a predetermined and registered personal user identification stored in the TMU or PLCA. Note, the ESN or user identification can also be known to the TMU or PLCA so that access to the PLCI  120  is limited only to predetermined access devices.  
         [0037]    The TMU  122  has some of the same capabilities as a standard telephone set. That is, the TMU can go “off-hook” upon detecting a ring signal. That is to say that the access device and TMU are activated to enable the user to communicate with the PLCI  120 .  
         [0038]    After the application layer PLC frame  200  is constructed, the TMU  122  sends the frame to the PLCA  128 , and the PLCA converts the PLC frame  200  to the appropriate PLN frame  310  used on the lines  132  of the PLN  103 . Note as a feature, the PLCI  120  can be used with any number of PLC protocols because the PLC frame  200  is constructed at an application level, independent of the physical layer of the PLC network  103 . Thus only the PLNA  126  needs to aware of how the PLC network  103  is implemented, e.g. 60 HZ, 110 volt or 50 HZ 220 volt, or the specific modulation techniques that is used to provided a carrier signal on the power lines. Similarly, the PLCI  120  is insensitive to the structure and protocol of the telephone network  101 , other than at the TMU  122 . Thus, the PLCI  120  provides a universal application level interface that can be adapted anywhere, this is in contrast with prior art home network that is specific for a particular physical layer protocol.  
         [0039]    In response to the broadcast of the frame, the associated PLC device adapter  140  processes the read/write actions specified in the frame. In the case of a read action, the PLC device constructs a response PLC frame, similar in structure, which travels back to the TMU  122 , and the TMU maps the frame to signals that can be viewed or heard by the PLC access device  111 . For example, temperature readings or timer values can be converted to text, audio signals, or graphical output.  
         [0040]    Internet Access  
         [0041]    In an alternative embodiment, the remote access device  111  includes an Internet browser support, and the PPS  124  has an Internet address. For example, the access device is an standard Internet enabled personal computer or wireless device, e.g., cell phone, PDA and the like. The remote access device  111  may also store a template presentation page for each type of home appliance. Upon detection of a new PLC device in the network  103 , a new presentation page, with appropriate control buttons is constructed All active presentation pages maintained by the PPS  124  are periodically updated via the PLNA or PLCA. Any presentation page can be “uploaded’ to the PLC remote access device  111  at any time. The user can browse through any device&#39;s presentation page, and perform read and write actions as described above, but now using a graphical user interface.  
         [0042]    Although the invention has been described by way of examples of preferred embodiments, it is to be understood that various other adaptations and modifications may be made within the spirit and scope of the invention. Therefore, it is the object of the appended claims to cover all such variations and modifications as come within the true spirit and scope of the invention.