Abstract:
A system for establishing a universal or overlapping wireless broadband network composed of a plurality of Access Points (AP). These APs may be coupled to existing copper transmission lines, and may work alone or in groups to provide wireless network access. Different types of APs may be utilized to perform various communication-functions, and these nodes may obtain power and/or communication resources from the existing copper transmission lines. Further, peripheral devices may be coupled to nodes to provide ancillary functionality to the system.

Description:
BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to a system for providing a wireless connection to a wide area network, and more specifically, to establishing a network of wireless access points supported, at least with respect to power and communications, by existing transmission lines. 
     2. Description of Prior Art 
     Public access through copper wire connection to the Internet has for many years been provided by means such as Cable Modems or modems on Digital Subscriber Lines. One or more subscribers on Cable Modems may share the bandwidth of a single physical link, and so the available bandwidth may be limited if there are multiple concurrent transfers. Digital Subscriber Lines (DSL), on the other hand, provide a separate physical link per subscriber. Although DSL bandwidth was initially limited, emerging technologies, such as VDSL2, are able to provide up to 100 Mbit/second throughput per subscriber. Further, both of these access methods require a wired connection to a cable or telephony network which eventually connects to the Internet. 
     In a typical use scenario, at least one computing device may be coupled to a DSL modem providing access to the Internet for a subscriber through a standard telephone twisted copper wire pair. This copper-wire connection eventually couples to communication equipment, for example, a Digital Subscriber Line Access Multiplexer (DSLAM), which may aggregate a plurality of such front-end connections for the transmission of the combined signals over media capable of higher communication volume (e.g., fiber optic cable), but occasionally over landlines or radio links. Internet Service Providers manage these connections, receive subscriber information from DSLAMS, and convey the received information to required destinations, such as other ISPs and DSLAMS, over the Internet backbone. 
     More recently, emerging wireless technology has been able to provide telephony voice and data transmission—typically using mobile cellular communication devices—over licensed radio bands without requiring a user to be physically tethered to the network over a cable connection. However, licensed bandwidth is somewhat limited. Building on this idea of using wireless communication media to remove the need for a wired connection to a network, radio connection devices based on unlicensed radio bands, known in some cases as wireless Access Points (AP), have been introduced between a hardwired modem and wirelessly-enabled computing equipment. A wireless Access Point, typically powered by wired power connection, may allow one or more wirelessly enabled computing devices within effective transmission range of the of the Access Point to access the Internet. One exemplary technology known in the industry is Wi-Fi, and the region within the radio range of the AP is known as a Wi-Fi Hotspot. 
     Some municipalities are installing, or are proposing to install, a network of overlapping Hotspots in order to provide “universal” access to the Internet for public use. This wireless access may be used for education, for law enforcement, or for other government service use. To date, the majority of these wide-area public hotspot networks have been provided with Internet access directly through fiber optic cable or wireless broadband backhaul, and the Access Point nodes have been powered by connecting to the power grid through street lights or building wiring and where power grid failure must be ameliorated by the use of local batteries. Such wide-area networks have proved expensive and difficult to install, the expense and difficulty coming at least from installing new fiber cable and from obtaining access to power. 
     What is therefore needed is a system for providing universal or overlapping wireless broadband access to users that is easy and cost-effective to install, as well as being manageable to support while providing adequate coverage and performance to meet user needs. 
     SUMMARY OF INVENTION 
     The present invention includes at least a device and system for establishing a universal or overlapping wireless broadband network composed of a plurality of Access Points (AP). These APs may be coupled to existing copper transmission lines, and may work alone or in groups to provide wireless network access. Further, different types of APs may be utilized to perform various communication-functions. 
     In at least one embodiment of the invention, the relationship between a node and an existing copper transmission line may be multi-faceted. An aerial mounting on a transmission line may, for example, provide a beneficial vantage point from which the AP may be able to receive information from a large number of wireless-enabled computing devices. The transmission line may also provide a wired communication path for the AP to communicate with other APs or possible a central information collection facility. Further, the AP may receive power from the transmission line supplied from a central battery whose charge is maintained automatically. All of these requirements may be serviced by an existing copper transmission line, which minimizes the amount of installation required for the system and separates the power source from the vagaries of the power grid. 
     Further, in another example of the invention, different types of APs may be employed in the creation of the wireless network. These APs may include active nodes, support nodes and nodes that support connection of peripheral devices. For example, a surveillance system may be integrated with the wide area network to improve security. Again, all of these features may utilize existing wired resources in order to avoid a costly and difficult installation. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The invention will be further understood from the following detailed description of a preferred embodiment, taken in conjunction with appended drawings, in which: 
         FIG. 1  discloses an example of an array of overlapping network access points coupled to one or more transmission lines in accordance with at least one embodiment of the present invention. 
         FIG. 2  discloses an exemplary access point configuration in accordance with at least one embodiment of the present invention. 
         FIG. 3  discloses an exemplary access point configuration including an active node and a support node in accordance with at least one embodiment of the present invention. 
         FIG. 4  discloses an exemplary functional diagram of an access point active node configuration in accordance with at least one embodiment of the present invention. 
         FIG. 5  discloses an alternative functional diagram of an access point active node configuration in accordance with at least one embodiment of the present invention. 
         FIG. 6  discloses an exemplary functional diagram of an access point support node configuration in accordance with at least one embodiment of the present invention. 
         FIG. 7  discloses an exemplary access point active node source pair generating configuration in accordance with at least one embodiment of the present invention. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     While the invention has been described in preferred embodiments, various changes can be made therein without departing from the spirit and scope of the invention, as described in the appended claims. 
     I. Components of the PowerReach System 
     The present invention, in at least one embodiment, may provide an array of AP nodes, called a PowerReach array, made up of PowerReach Active Nodes and PowerReach Passive Nodes. Both types of nodes may contain at least a radio transceiver to provide coordinated xDSL wireless Internet access for a region larger than just one hotspot. In a further example of the present invention, coordinated xDSL Internet access may be provided for ancillary functionality by means of PowerReach Support Nodes, which may not contain a radio transceiver, and also by support facilities incorporated on PowerReach Active Nodes. Radio controlled ancillary functions may also be supported by the PowerReach Facility Passive Nodes. 
     Both xDSL Internet access and power may be provided over existing telephony copper wires for PowerReach Active Nodes (PAN) and PowerReach Support Nodes (PSN), and at least power may be provided over existing telephony copper wires for PowerReach Passive Nodes (PPN). The set of node types comprising the PAN, PSN, and PPN may be generically referred to as PowerReach Facility Nodes. The PowerReach Facility Nodes may operate together to provide a system with high reliability of area radio coverage and operational fault tolerance. 
     At least one important feature of the present invention is the ability to provide battery backed power to the PowerReach Facility Nodes over one or more pairs of existing copper wires. The basic power source may be a central telephony installation, in which batteries are continually replenished under trickle charge, and in some instances, this primary power source may be further backed up by diesel generators. However, standard −48 volt telephony batteries can only supply adequate power over short distances because of resistive loss on the copper wires, even if only the Ring line is used and terminated at a ground source instead of returning to the battery connection over the Tip line. For longer distances a form of “derived power” may be required, wherein the −48 volt batteries at the central telephony installation may be electronically “enhanced” to a much higher voltage, for example ±190 volts, before being placed on the Ring and Tip conductors. Enhancing the voltage in this manner reduces the current requirements, and hence the resistive transmission loss, for a given power transmitted. This enhanced voltage is then converted back to a local working voltage (e.g., −48 volts) at the PowerReach Facility Nodes, thereby providing the required power. 
     The following terms are defined only for the sake of example and explanation when used in the following disclosure, and are not intended to be limiting. A “network,” for example, may be a group of two or more nodes connected by radio, fiber, copper wires, or other media links for the purpose of transferring data among devices. The data may be a continuous isochronous stream composed of a series of dynamically sized packets, or alternatively, a series of uniform sized cells containing header and payload information. Control information may be contained in the header or in the payload. Connection links may be point-to-point, or point-to-multipoint. Each node may connect to multiple links and/or multiple devices through ports. A “bridge,” for example, may be defined as an element of a node that connects nodes of two or more networks that share the same protocol at the physical level: it decides only if an incoming cell or packet should be transferred to one or more ports on the node, or forwarded on a link to another network. A “router,” for example, may be an element of a node that knows how to forward a cell or packet in the node to its destination. A “gateway,” for example, may be a network node that connects two or more networks, acting as an exit and egress point: the networks may use different protocols. A “modem,” for example, may be a device that allows a computer or terminal to transmit data over a standard telephone line or a television distribution cable. A “transmission line,” for example, means a telephony copper twisted pair. The term transmission line in other contexts may include microwave transmission lines with specialized cable having wires held parallel at a predetermined fixed distance. 
     II. Overlapping or Universal Wireless Network Coverage 
       FIG. 1  discloses an idealized array of PowerReach Facility Nodes to support a Wireless Metropolitan Area Network (WMAN) in accordance with at least one embodiment of the present invention. The node array is shown powered, for example, from −48 Volt Central Power. 
     The black circles in  FIG. 1  depict the transmission areas reliably supplied with radio access to a set of PANs  112 , which are each depicted as connected by aerial copper wires to a central telephony installation (for example  102  and  106 ). The telephony installation may supply both power derived from −48 volt batteries, and Internet access for each PAN  112 . The copper wire connections are shown as connections to aerial transmission lines by way of example, as the connections could equally well be supplied by buried copper cables. 
     The grey circles depict the radio transmission areas reliably supplied with radio access to a set of PPNs  110  which are not directly connected to the Internet (for example  100 ,  104  and  108 ). These passive nodes may be interspersed between the PANs  112 , such that no PAN  112  is separated by more than one PPN  110  from any of its neighboring PANs  112  to improve the fault tolerance of the network. As a consequence, in this exemplary arrangement no subscriber or user need ever be further away than one PPN  110  effective transmission range diameter from any two PANs  112 . Internet access may be provided by supporting wireless routing or bridging capabilities in the APs to one or more PANs  112 . 
     The proportion of PAN  112  to PPN  110  is adjustable from an all PAN  112  network, to a PAN  112  to PPN  110  ratio determined by traffic capacity or fault tolerance requirements. In a scenario where fault tolerance and traffic capacity is of less importance, the ratio could go to an all PPN  110  network having a radio backhaul from one or more of the PPNs  110 . A mixture of radio bands may be used, providing that there are sufficient nodes present able to support bridging between more than one of the radio bands to ensure coordinated Internet access. Similar to the PAN  112  example disclosed above, each PPN  100  is depicted as being provided with operating power derived from −48 volt central batteries, and supplied over an aerial copper wire connection from a central telephony installation. The copper wire connections are shown as aerial connections by way of example, and the connections could equally well be supplied by buried cable. 
     In the example disclosed in  FIG. 1 , the PowerReach Facility nodes are shown as being placed in a regular array. This distribution may be an idealized situation, and it should be understood that practical limitations of mounting location, copper wire location, and radio transmission anomalies may cause the array to be irregular. If required, overlapping reliable radio transmission areas for each PowerReach Facility Node may be maintained in such a practical array by a mixture of the two aforementioned radio node types. Further, all PowerReach Facility nodes  110  and  112 , as disclosed in  FIG. 1 , depict omni-directional antennae coverage. Omni-directional antennae coverage is beneficial to maintain a blanket or overlapping coverage for the region served by a PowerReach Array. However, where circumstances require, a particular PowerReach Facility node may be provided with a directional antenna. 
     III. PowerReach Active Node 
     In  FIG. 2 , PAN  112  is depicted as consisting of two equipment boxes ( 204  and  206 ) connected together by a cable, such as category 5 (or greater) four pair cable. This cable may carry at least an Ethernet 10/100 bi-directional bus connection and −48 volt power, for example, in a configuration known as “Power over Ethernet” (PoE). The previously indicated boxes ( 204  and  206 ) may be suspended by metal brackets from an electrically grounded aerial copper telephony cable  210 . 
     On the left hand side of the drawing a connection from a copper aerial cable  200  to a distribution box  208  (DSP, or Distribution Signal Point) mounted on the telephone pole is disclosed. This connection may carry an xDSL signal and a derived power signal, and may be connected to the distribution box terminal as a means of securing the end of the connection. From there, a further connection is taken to convey the derived power and xDSL signals to the first of the two boxes  206  comprising the PAN  112 . The detail of the contents of this box is described in relation to  FIG. 4 , but its purpose, in accordance with at least one embodiment of the present invention, is to contain the circuitry for obtaining the necessary working voltage, for example −48 volts, from a derived power signal, to obtain control signals, and to extract and insert data (which may contain Internet and/or wireless data and/or voice), from and to the xDSL signal. 
     The control, bi-directional media and data signals, and power voltage may be carried from the first box  206  to a second box  208  by the previously indicated type of cable. Second box  208  may contain a Wi-Fi AP (or radio transceiver) that performs the active radio modulation/demodulation and other functions required to enable wireless communication with the node. 
     Although the example of PAN  112  disclosed in  FIG. 2  has been shown as two boxes, and suspended in an aerial transmission line configuration, this is only by way of an example, and it can alternatively have all of the required functionality contained in one box, and could alternatively be building or pole mounted with an adequate electrical ground connection. 
     IV. PowerReach Active Node and Support Node 
       FIG. 3  discloses an example of a PowerReach Support Node  300 , and additional support functionality added to a PAN  112 . On the left side of the figure is shown a PSN  300  supporting the operation of surveillance camera  302 , by way of an example of the possible functionality that PSN  300  may support. Other possible functionality supportable by PSN  300  may include, but is not limited to, a voice terminal, audio pickup equipment, audio broadcast equipment, alarms, and visual displays. Functionality such as surveillance camera  302  presently deployed in the field may require large amounts of local memory. With the availability of access to the Internet provided by PSN  300 , a shared central memory may be provided to fill this need. 
     On the right hand side of the figure is shown (e.g., at  304 ) a PAN  112  with a support function attached. Once again, surveillance camera  302  is shown by way of an example of equipment whose operation may be supported. The ultimate number of peripheral devices or functions that may be supported by a single node depends on the electrical power and/or bandwidth delivered to the node. If the power or bandwidth available from a single copper pair is insufficient, an additional one or more copper pairs may be attached to fill any deficiency. 
     The PSN  300  and the PAN/PSN combination  304  are shown supplied by different copper pairs from the same multi-pair cable. Once again, this is by way of an example, as the power and control and bidirectional data signals may be supplied by any copper pair connected to a central telephony installation. 
     V. PowerReach Active Node Components 
     Referring now to  FIG. 4 , PAN  112  may function to power a Wi-Fi Access Point transceiver  420  and activate a connection for data and control between the AP and an xDSL connection  414  to the Internet. It may also provide the power, data and control signals to other equipment, such as, for example, a surveillance camera, voice terminations, or other media in a configuration previously shown, for example, at  304 . To illustrate this, a connection to camera  302  is shown as a dotted section of the right side of  FIG. 4 . 
     On the left side of  FIG. 4  is shown an incoming copper pair from the centralized telephone facility. It may be first connected to a circuit  410  which provides protection to the node from lightning, surges, voltage spikes, and accidental cross connections with power lines. The signals from this incoming connection are then partitioned between the upper path through a low frequency pass filter (LPF)  400  to the power generation circuits  402 , and the lower path through a high frequency pass filter (HPF)  412  to the xDSL terminating circuits  414 . 
     An alternative arrangement (not pictured) may include having one pair of wires carrying the power derived from the copper pair transmission lines to a protection circuit and then directly to the power generation circuits  402 , and a second separate pair of wires carrying the xDSL signals to a similar protection circuit and then directly to the xDSL terminating circuits  414 . Where the derived power provided by one pair of wires is insufficient to support the load of multiple ancillary circuits, an additional pair, or pairs, of conductors carrying derived power may be brought in directly as described above to additional power generation circuits  402 . 
     Power circuit  402  generates a local working power voltage (e.g., −48 volts) from the incoming derived power. The power generating circuitry may be duplicated to provide fault tolerance, if required, to increase the overall reliability of the node. The regenerated working voltage may further be converted by equipment (not shown) to lower the voltage to levels required to power the xDSL modem  414  and power delivery circuits. The working voltage then passes through a second low frequency pass filter  404  before being available for transfer to the Wi-Fi AP  420  or other equipment. 
     The xDSL circuit may consist of at least an xDSL intelligent modem  414  that may provide gateway functions, and may further provide firewall, web server, security, configuration, management and/or other software features. The control and data streams from and to this modem then traverse through a second high pass filter  416 , before being available for transfer to the Wi-Fi transceiver or other equipment. Where additional throughput capacity is required, a technique is known to “bond” two xDSL circuits together. This bonding may require two copper pairs, and the traffic is partitioned between the two circuits. For PAN  112  to accommodate this configuration, a second copper pair carrying a second portion of the bonded signals must be coupled to the node, through a protection circuit such as  410 , and through high frequency pass circuit  412  into a specially designed modem to extract the data and control from the bonded set of signals. 
     A “Power over Ethernet (PoE)” circuit known as a Power Sourcing Equipment (PSE) Controller  418  may be used to combine the control and data stream carried on the Ethernet over two pairs, with the working power voltage (e.g., −48 volts) on the remaining two pairs of the four pair category 5 (or greater) cable to the Wi-Fi transceiver. The −48 volt power may also, or alternatively, be carried on the signal or data wires. A similar circuit  406  may be used for camera  302  or other equipment. A further connection is shown between the AP and the camera so that control signals received by radio on the transceiver may be sent to the camera. A connection and equipment similar to PAN  112  may be used in PSN  300  to drive and control a set of surveillance cameras and/or other peripheral devices as noted in the discussion of  FIG. 3 . 
     In  FIG. 5 , it is further anticipated that some Wi-Fi transceivers and ancillary equipment may require AC power, for example 110 volts at 60 cycles per second. For these, and any other peripheral devices noted in  FIG. 3-4  above that may require AC power, the PSE circuit  418  may be replaced by a power inverter (INV)  500  that converts the local working DC voltage into the required AC voltage. The rest of the functionality as described for  FIG. 4  remains the same. Control, data, and voice signals may be carried over an Ethernet bus over two pairs of the four pairs in Category 5 (or greater) cable and the AC power is supplied via a separate power cord. 
     VI. PowerReach Passive Node Components 
     A PPN  110  may be utilized to extend the effective range of surrounding PANs  112 . It may also provide for radio control of other equipment such as surveillance camera  302 . To illustrate this, a connection to a camera is shown as a dotted section in  FIG. 6 . The left side of  FIG. 6  shows an incoming copper pair from the centralized telephone facility in a similar manner to PAN  112 . It is first connected to a circuit  410  which provides protection to the node function from lightning, surges, voltage spikes, and accidental cross connections with power lines. The signals from this incoming connection are then taken through low frequency pass filter  402  to power generation circuit  402 . 
     Since, in at least one embodiment of the present invention, power requirements in the basic PPN  110  are much less than for PAN  112 , it is possible that a standard −48 volts may be sufficient. If −48 volt power is supplied, multiple copper wire pairs may be required. A further possibility is for −48 volts from the central telephony battery to be carried on both the Ring and Tip wires, both of which would need to be terminated on the ground wire. Although the Ring (or both) wires of these pairs will be terminated on an electrical ground wire, the voltage will be smaller than the original −48 due to resistive loss, and so voltage conversion may be required. 
     Thus, power circuit  402  will generate a local working voltage (e.g., −48 volts) from the incoming derived or unmodified power voltages. As in the case of PAN  112 , the power generating circuitry may be duplicated to provide fault tolerance, if required, to increase the overall reliability of the node. The local working voltage then passes through low pass filter  500  before being available for transfer to the Wi-Fi transceiver or other equipment by means of PSE circuit  418  or an inverter (not shown) as described for  FIGS. 4 and 5  above. As with PAN  112 , camera  302  may be coupled to the power and communications of PSN  110  through PSE  406 . 
     VII. Active Node Source Pair Generation 
     Base equipment located at the central telephony installation may be used, in at least one embodiment of the present invention, to reliably supply the combined power and xDSL signals through the copper wire connections to each PAN  112  and PSN  300 , and at least power for each PPN  110 . Each PowerReach Node is usually supplied with these resources individually. 
       FIG. 7  discloses exemplary equipment that may be located at a central telephony installation. In the case of PPN  110 , the power may, in some instances, be supplied directly from the telephony installation&#39;s batteries, and possibly applied to both Ring and Tip wires. For all PPN where such is not the case, and for all PAN  112  and PSN  300 , derived power  708  (e.g., ±190 volts) is generated per individual line by means of generating equipment, optionally duplicated or made fault tolerant, fed from the telephony installation&#39;s batteries. The power so generated is then fed through a low pass filter  710 , and merged with the xDSL signal. 
     The xDSL signals may be generated by one or more DSLAM units  700  which may supply multiple subscribers, and may obtain source data from the Internet in the form of multiplexed digital signals over optical fiber cables, or via wireless communication including technologies such as microwave antennae, or via electrical cables communicating using media such as, for example, SONET. In order to provide optional fault tolerant service, duplicate DSLAM units  700  may be provided as shown in  FIG. 7 , with A/B switch  702  to select the preferred server. As an alternative (not shown), optional fault tolerant service may also be provided using n+m redundancy, with a matrix switch for selecting an operable channel. The selected channel traverses a high pass filter  704  before being merged with the selected power source  708 . The merged signals are then passed through a circuit  706  which provides protection from lightning, surges, voltage spikes, and accidental cross connections with power lines. 
     The present invention includes, in at least one embodiment of the present invention, a wide area network may be installed using conventional copper transmission lines. This implementation may allow for easy and cost-effective implementation of a municipal or public access wireless network in locations that are convenient to provide universal or overlapping coverage to subscribers. Further, peripheral devices may be integrated into the system to allow for additional functionality that may benefit the public, for example, surveillance cameras to assist in public security, information displays for informing the public of civic events or during an emergency, etc. 
     Accordingly, it will be apparent to persons skilled in the relevant art that various changes in forma and detail can be made therein without departing from the spirit and scope of the invention. Thus the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.