Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    There are a variety of different transmission interfaces for communications, including wireless and wired communications. Wired communications are typically employed over wires dedicated solely for supporting communications, e.g., the public switched telephone network (PSTN). Another type of wired communications, commonly referred to as powerline communications, employs electrical powerlines to carry communications. In particular, communication signals are modulated onto the powerline by a transmitter and then demodulated by a receiver. 
       SUMMARY OF THE INVENTION 
       [0002]    Powerline communications can be particularly useful for businesses. Specifically computer networks, such as local area networks (LANs), and private branch exchanges (i.e., private telephone networks) typically require dedicated wires. If the premises are not wired to support a LAN or PBX then the business will have to pay to have the wiring added. When the business later relocates to different premises the cost of wiring is not recouped. Additionally, once the outlets for the LAN or PBX are installed, the furniture must be arranged around these outlets. Unlike LAN and PBX installations, which require a home-run from the outlet to the switch, powerline communications can be supported using outlets that are coupled serially. Thus, a new outlet can be run off of an existing outlet. 
         [0003]    Systems and methods for powerline communications are provided. An exemplary system includes a controller and an extension unit. The controller includes a plurality of transceivers, each of the plurality of transceivers are coupled to a powerline network, and a switch coupled to each of the plurality of transceivers. The extension unit includes a transceiver coupled to the powerline network and an interface to a communication unit. The controller is coupled to a broadband wireless network via the powerline network and the switch of the controller switches communications between the extension unit and the broadband wireless network. 
         [0004]    The controller and extension unit can each include a voice compressor. The communication unit can be a public switched network (PSTN) or private branch exchange (PBX) telephone and the extension unit can also include a digital-to-analog/analog-to-digital converter coupled to the extension unit transceiver and a subscriber line interface coupled between the digital-to-analog/analog-to-digital converter and the PSTN or PBX telephone. The communication unit can be a Voice over Internet Protocol (VoIP) telephone or a computer and the extension unit can also include a session initiation protocol (SIP) and media gateway coupled between the extension unit transceiver and the VoIP telephone or computer. 
         [0005]    The extension unit can also include a digital-to-analog/analog-to-digital converter coupled to the extension unit transceiver, a subscriber line interface coupled to the digital-to-analog/analog-to-digital converter and a session initiation protocol (SIP) and media gateway coupled to the extension unit transceiver. 
         [0006]    The system can include a plurality of unit controllers, each of the plurality of unit controllers are coupled between a respective one of the plurality of transceivers and the switch. The system can also include a broadband transceiver coupled between the controller and the broadband wireless network. The extension unit transceiver and the plurality of transceivers can modulate communications onto a powerline of the powerline network. The communications can be voice communications and/or data communications. 
         [0007]    The controller can provide private branch exchange functions, including switching incoming calls to the extension unit, establishing an intercom between the extension unit and another extension unit, placing a call on hold, transferring a call from the extension unit to another extension unit, for varding a call from the extension unit to another extension unit. 
         [0008]    Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0009]      FIG. 1  is a block diagram of an exemplary system in accordance with the present invention. 
           [0010]      FIG. 2  is a block diagram of an exemplary central control unit in accordance with the present invention. 
           [0011]      FIGS. 3A-3C  are block diagrams of exemplary extension units in accordance with the present invention. 
           [0012]      FIG. 4  is a block diagram of an exemplary filter in accordance with the present invention. 
           [0013]      FIG. 5  is a flow diagram of an exemplary method in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]      FIG. 1  is a block diagram of an exemplary system in accordance with the present invention. The exemplary system includes a powerline network  102  that couples central control unit  104  to a plurality of extension units  106 ,  110 ,  114  and  118 . Central control unit  104  is coupled to the PSTN  126 , and broadband network  124  via broadband transceiver  122 . Broadband network  124  can be, for example, a WiMAX network, LTE network and/or the like. Central control unit  104  allows any type of telephone or computer to exchange communications with another telephone or computer, broadband network and/or PSTN by plugging an extension unit the central control unit and broadband transceiver  122  into an electrical outlet. Additionally, central control unit  104  can provide any type of PBX functionality to extension units  106 ,  110 ,  114  and  118  including switching incoming calls to different extension units intercom between extension units, placing calls on hold, transferring calls between extension units, forwarding calls to different extension units, and the like. 
         [0015]    Extension unit  106  couples Voice over Internet Protocol (VoIP) phone  108  to central control unit  104 , extension unit  110  couples public switched telephone network (PSTN) phone  112  to central control unit  104 , extension unit  114  couples computer  116  to central control unit  104  and extension unit  118  couples private branch exchange (PBX) phone  120  to central control unit  104 . 
         [0016]      FIG. 2  is a block diagram of an exemplary central control unit in accordance with the present invention. Central control unit  104  includes a power plug  202  that is inserted into an electrical outlet to couple the central control unit to powerline network  102 . Power plug  202  is coupled to a plurality of electrical components associated with each extension unit. For each extension unit central control unit  104  includes a powerline receiver  204   1  coupled to power plug  202  and a slave unit controller  206   1 . Slave unit controller  206   1  is coupled to slave unit controller  208   1 , which in turn is coupled to powerline transmitter  210   1 . Slave unit controller  206   1  is coupled to switching microcontroller  212 , which in turn is coupled to master microcontroller  214 . 
         [0017]    Powerline receiver  204 , and powerline transmitter  210   1  can be embodied as separate components or as a single transceiver. Regardless, the component will include the ability to support half-duplex frequency shift key (FSK) modulation, and include an integrated powerline driver with programmable voltage and current control. The transceivers can operate at programmable transmission frequencies and/or baud rates. The receiving sensitivity can be adjusted, and the transceiver also provides carrier or preamble detection. Any of the aforementioned functions can be adjusted using a programmable control register. 
         [0018]    Master microcontroller  214  is coupled to database  216  and voice compressor  218 . Voice compressor  218  includes a decoder  220  and encoder  222 . Master microcontroller  214  controls the interfacing with the subscriber line interface cards of the extension units and powerline transceivers. Master microcontroller  214  communicates with switching microcontroller using USART communications. Master microcontroller  214  also manages the PBX functionality, such as any of the PBX functionality discussed above. 
         [0019]    Switching microcontroller  212  is responsible for coupling communications between the various extension units, and also between extension units and broadband network  124  and/or PSTN  126 . This switching is controlled by master microcontroller  214 , using information stored in database  216 . Database  216  includes information about the status of each extension unit so that master microcontroller  214  can determine whether the extension unit is busy or available to take an incoming communication. Database  216  can also include other information necessary for supporting PBX functionality. 
         [0020]    Voice compressor  218  compresses and decompresses voice for transmission over the powerline network either to other extension units or to broadband network  124  or PSTN  126 . 
         [0021]      FIGS. 3A-3C  are block diagrams of exemplary extension units in accordance with the present invention. Extension unit  300 , can be used to support a PSTN telephone and/or PBX telephone  322  for communicating with powerline network  102 . Extension unit  300   1  includes a power plug  302  that can be inserted into an electrical outlet to couple the unit to powerline network  102 . Power plug  302  is coupled to a powerline receiver  304 , which in turn is coupled to a slave unit controller  306 . Slave unit controller  306  is coupled to decoder  314  of voice compressor  812 . Power plug  302  is also coupled to powerline transmitter  310 , which in turn is coupled to slave unit controller  308 . Slave unit controller  308  is coupled to encoder  316  of voice compressor  312 . 
         [0022]    Powerline transmitter and receiver  304  and  310  can be separate components or can be integrated into a single transceiver, Regardless, the component will include the ability to support half-duplex frequency shift key (FSI) modulation, and include an integrated powerline driver with programmable voltage and current control. The transceivers can operate at programmable transmission frequencies and/or baud rates. The receiving sensitivity can be adjusted, and the transceiver also provides carrier or preamble detection. Any of the aforementioned functions can be adjusted using a programmable control register. 
         [0023]    Voice compressor  312  is coupled to an analog-to-digital converter/digital-to-analog converter  318  (ADC/DAC), which in turn is coupled to a subscriber line interface card  320 . ADC/DAC converts digital voice from compressor  312  into analog voice for subscriber line interface card  320  and vice versa. Subscriber line interface card  320  includes an input to accept a connection to PSTN telephone/PBX telephone  322  in order to couple the telephone to the central control unit. 
         [0024]    The extension unit  302   2  of  FIG. 3B  is similar to that of extension unit  300   1  of  FIG. 3A , except that extension unit  302   2  is used for coupling a VoIP telephone and/or computer  326  to powerline network  102 . Extension unit  302   2  includes a session initiation protocol (SIP)/media gateway  324 . When extension unit  302   2  is coupled to a computer, communications between slave unit controllers  306  and  308  and SIP/media gateway, 324  need not pass through voice compressor  312 . If the VoIP phone/computer  326  is compatible with analog signals., then extension unit  302   2  can also include an ADC/DAC  318  and subscriber line interface card  320 . 
         [0025]    Extension unit  300   3  of  FIG. 3C  includes the ability to couple both PSTN telephone/PBX telephone  322  and VoIP telephone/computer  326  to powerline network  102 . This provides the added flexibility that extension unit  300   3  can be employed with any type of communication device. 
         [0026]    As discussed above., powerlines are particularly noisy. Accordingly, exemplary embodiments of the present invention can employ the filter of  FIG. 4  between the powerline and the transmitter/receiver of the central control unit and the extension units. The filter includes a transmit active filter  405  that receives signals from the transmitter and passes the signals to a transmit passive filter  410 . Transmit passive filter passes the signals to isolator  415 , which in turn passes the signals to the powerline network. Isolator  415  can be, for example an optical isolator. 
         [0027]    Communication signals received from the powerline network pass from isolator  415  to transmit passive filter  410 , and then to receive passive filter  420 . Receive passive filter  420  passes the filtered signals to the receiver of the central control unit or extension unit. The various filters can be arranged to filter out noise and can be tuned to particular frequencies and amplitudes in which the communication signals are carried. For example, the filters can be tuned to pass signals in the 1800 MHz and 2.4 GHz bands. 
         [0028]      FIG. 5  is a flow diagram of an exemplary method in accordance with the present invention. Master microcontroller  214  communicates with switching microcontroller  212  every 20 milliseconds (step  505 ) in order to determine whether there is an off-hook or ring signal (step  510 ). When there is not an off-hook or ring signal (“No” path out of decision step  510 ), master microcontroller  214  waits another 20 milliseconds to communicate with switching microcontroller  212 . When switching microcontroller  212  informs master microcontroller  214  of a ring signal (“Ring Signal”) path out of decision step  510 ) master microcontroller  214  initiates the ringing process (step  515 ). Specifically, master microcontroller checks the status of the destination extension unit (e.g., busy or available) and then sends a ringing signal to the destination extension unit. 
         [0029]    Master microcontroller  214  waits for an off-hook condition and then starts the voice communication between the call originator and the call destination (step  520 ). When master microcontroller  214  detects an on-hook condition for the extension unit then master microcontroller resets the extension unit in database  216  (step  625 ), and then it continues to communicate with switching microcontroller  212  (step  505 ). 
         [0030]    When switching microcontroller  212  informs master microcontroller  214  of an off-hook condition for a particular extension unit (“Off-Hook” path out of decision step  510 ), master microcontroller  214  updates the database of the off-hook status of the extension unit and waits for DTMF signals corresponding to a dialed telephone number (step  530 ). Master microcontroller  214  then sends the dialed digits in a packet header to the destination extension unit (step  535 ) and sends a ringing signal to switching microcontroller  212  (step  640 ). Master microcontroller  214  then waits for a busy signal or the initiation of the call (step  545 ) and in the case of a call initiation starts voice communications between the call originator and call destination (step  550 ). Upon detecting an on-hook condition: master microcontrouer  214  restarts the extensions (step  525 ) and continues to communicate with the switching microcontroller  212 . 
         [0031]    The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof

Technology Category: h