Patent Publication Number: US-2007121548-A1

Title: Network generating system and method

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority to and benefit from U.S. application Ser. No. 60/730,064, filed on Oct. 25, 2005 under §119(e). 
    
    
     BACKGROUND OF THE INVENTION  
      1.Field of the Invention  
      The present invention relates generally to a system and method of generating a communications network and more specifically to a device or a plurality thereof that may be employed in combination to connect network hosts together to act as a cable, fiber or wire line communications network replacement.  
      2.Description of the Related Art  
      Wireless data communications networks are well known in the art, cellular phones being a prime example of such systems. Recent advances in radio frequency transceiver integrated circuitry and antennae which can be printed directly onto circuit boards have made very compact wireless communications devices relatively inexpensive to manufacture and as such, readily available to the public.  
      Furthermore, wireless Internet transmission technologies have proliferated as wireless local area networks (WLANs) have become more reliable and available in many urban centers. Typically, WLANs are implemented having an Internet connected port, typically a DSL line or DIA circuit, then have various clients connect to the WLAN at an access point, commonly known as a “hot spot”. The client is free to move within apredetermined localized range of the hot spot without interruption in Internet communications. In exemplary WLAN systems, the access point is coupled to a bridging device or wireless router that is in turn connected to a base station that serves as a Network Operations Center for Internet connection.  
      Other types of wireless communications networks include systems wherein wireless devices communicate point-to-point with each other. In this methodology, wireless devices transmit and receive from device-to-device (or structure-to-structure), thereby creating a mesh or matrix of communications nodes used to transmit data from one location to another. An example of this type of device is the ubiquitous microwave tower, prevalent across the landscape until replaced in large part by satellite communications systems.  
      The Internet functions as an enormous communications network by linking a plurality of host computers into a great series of networks that are interconnected by routers via the copper wire or fiber optic telecommunications infrastructure. Additionally, the predominant network communications protocol for modern networks is often Ethernet communications, due to its high speed and low cost data handling capabilities as well as the ease of providing most modern personal computers with Ethernet communications capability through the use of network interface cards (NICs).  
      There is a need, however, for a wireless Internet communications network that can extend far in excess of localized Wi-Fi hot spots, and that may be economically and robustly created by Internet service providers (ISP&#39;s) and client-users alike.  
     SUMMARY OF THE INVENTION  
      The present invention provides a system and method of generating a broadband wireless network by utilizing a plurality of network generating devices to transmit wireless data over a plurality of frequencies to other network generating devices placed within a specified distance. The network generating devices of the invention are capable of operating as host devices, routers, or network bridges depending upon user-supplied configuration inputs. Furthermore, the invention is relatively light and compact in size thereby facilitating its placement in a wide variety of locations throughout, for example, a neighborhood or local area.  
      The network generating devices of the present invention are further designed to provide a wireless communication system that is capable of both sending and receiving data by employing full-duplex Ethernet communications, utilizing CSMA/CA (carrier-sense multiple access/collision avoidance) to reduce or eliminate data loss due to collisions. The network generating devices of the present invention further incorporate multiple broadcast and receive channels carried over dedicated broadcast and receive antennas to permit the system to transmit and receive data in full duplex mode over multiple frequencies, in contradistinction to known wireless network devices.  
      A plurality of network generating devices may be placed at various locations, for example on structures in a local area wherein each device has at least one other device located within the transmission range thereof. Where a plurality of devices are located within transmission range of each other, a robust redundant network is provided that includes ample bandwidth for wireless Internet communications. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       FIG. 1  is a block diagram of a network generating device in accordance with one embodiment of the present invention.  
       FIG. 2  is a schematic diagram of a network generating device in accordance with one embodiment of the present invention.  
       FIG. 3  is a system diagram of a single network generating device connected to a host in accordance with one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)  
      Referring now to  FIGS. 1 and 2 , and in accordance with a preferred constructed embodiment of the present invention, a wireless network generating device  10  capable of implementing a wireless communications network comprises a plurality of antennas  20  capable of transmitting and receiving radio frequency (RF signals), particularly in the 2.4 GHz to 5.80 GHz range. The antennae  20  of the present invention are preferably capable of being integrated into a conventional printed circuit board as best seen in  FIG. 2 , thereby providing for an overall device  10  design package that is quite compact and capable of being contained within a weatherproof enclosure or the like. Furthermore, in one embodiment of the present invention at least one antenna  20  is dedicated to receiving data while at least one other antenna  20  is dedicated to transmitting data, thereby enabling the network generating device  10  of the present invention to operate in full duplex mode when transmitting data, as discussed in greater detail below.  
      Antennae  20  are electrically coupled to at least one amplifier  30  input  32  and/or output  34 . Amplifier  30  may operate as a signal conditioner and buffer for data signals transmitted by network generating device  10  as well as increasing the gain of signals supplied to amplifier input  32  for subsequent transmission over antenna  20 . Amplifier  30  may be one of many commercially available low-noise radio frequency amplifiers such as, for example a MAX 2649LNA integrated circuit produced and supplied by the Maxim Corporation. In one embodiment of the present invention a plurality of RF amplifiers  30  are electrically coupled to the plurality of antenna  20 , wherein each antenna  20  has a dedicated RF signal amplifier  30 . This feature of the present invention requires the dedicated receiving antenna  20  be electrically coupled to a buffer input  32  of amplifier  30  and further that dedicated transmit antenna  20  be electrically coupled to a transmit output  34  of amplifier  30 , to enable proper signal routing and enable full-duplex communications.  
      In one embodiment of the invention, the incoming data signal from the dedicated receiving antenna (the data signal being received) is not electrically coupled to amplifier  30 , but rather routed directly to an RF transceiver as discussed further herein below. In a yet further embodiment of the invention, amplifier  30  is capable of supplying an output  34  signal to be transmitted through antenna  20  at 950 mW of power, thereby providing sufficient signal strength to enable relative line of sight transmission of signals between network generating devices  10  within a predetermined distance. In one embodiment of the present invention, the device  10  transmits at a signal strength sufficient for the signal to be received by a corresponding device at a range of approximately two miles. One of ordinary skill will recognize that wireless Ethernet communications may be obtained at greater or lesser distances, depending upon various factors such as antenna size, radiating power, interference and geographical signal restrictions.  
      Network generating device  10  further comprises a radio frequency integrated circuit transceiver  50  having at least one signal input  52  and at least one signal output  54 . The input  52  of RF transceiver  50  is electrically coupled to the data signal received through dedicated receiving antenna  20  and may provide signal filtering and noise suppression. The output  54  of RF transceiver  50  is electrically coupled to an amplifier  30  input  36 , wherein the RF output signal is amplified prior to transmission. RF transceiver  50  further comprises at least one data output  56  electrically coupled to a data bus  100  and at least one data input  58  electrically coupled to data bus  100  wherein data signals to be transmitted are routed through input  58  from bus  100  while data signals being received are routed to data bus  100  through data output  56 .  
      The RF transceiver  50  may comprise alternative features such as programmable filters, signal gain controls, transmitted signal gain controls, and low power shutdown operation. Exemplary RF transceivers  50  include, but are not limited to a single/dual-band 802.11 integrated circuit transceiver, commercially available from the MAXIM Corporation and capable of operational compliance with 802.11 WLAN (wireless local area network) data communications standards. One of ordinary skill in the art will recognize that a wide variety of commercially available RF transceivers  50  may be employed in conjunction with the present invention, without departing from the scope thereof.  
      The network generating device  10  further comprises a microprocessor  140  having concomitant associated data memory in the form of flash RAM  142  and/or SDRAM  144 . Microprocessor  140  performs the function of a DSP (digital signal processor), conducting routing and gateway operations for the Ethernet network generated by the device  10  of the present invention, including segmentation tasks necessary to Ethernet network communications. Microprocessor  140  includes a port  146  in communication with bus  100  for routing data to and from microprocessor  100  as well as other components of network generating device  10 . In one embodiment of the present invention, microprocessor  140  is capable of providing a serial or parallel interface to an Ethernet communications network utilizing IEEE 802.11 or 802.3 communicating protocols. An exemplary microprocessor is an AT76C520 Network Processor available from, for example, the ATMEL® Corporation.  
      The network generating device  10  of the present invention further comprises an Ethernet controller  200  and associated RJ45 Ethernet jack  210  which enables a peripheral device such as a personal computer or other microprocessor or host capable of communications over an Ethernet communications network to access the network generating device  10  of the present invention. The Ethernet controller  200 , for example a 10/100 Base-T PX-5115 available from Mags.com® provides transmit and receive signal isolation as well as one port plug-in access to the network generation device  10 .  
      In a yet further embodiment of the present invention, a power-over-Ethernet injector  220  is employed to provide a direct current power source (DC) of, for example 6 to 12 volts, to the various components of device  10 . Furthermore a conventional power transformer  230  may be employed to step down the dc voltage supplied by the power-over-Ethernet injector  220  to a voltage level suitable for powering the integrated circuits required to implement the network generating device  10 . In one example power transformer  230  may provide a 3.5 Vdc output to the integrated circuits  30 ,  50 , and  140  employed in the invention  10 . An exemplary step-down voltage regulator is produced by National Semi-Conductor under part number LM2676 may be employed to step down an 8 to 40 Vdc input down to a suitable DC supply voltage for integrated circuit applications. This power arrangement permits for cable lengths from the network generating device  10  to a client device near the maximum allowable cable length for Ethernet communications, thereby providing for great flexibility in positioning the devices  10  depending upon customer needs and geographical requirements. In most n suburban neighborhoods, this distance greatly exceeds the distance from the street to most residences.  
      In operation, the network generating device  10  may be employed in conjunction with like devices  10  as well as one or more host computers to provide for a wireless Ethernet network which may extend indefinitely across free space. The network generating devices  10  communicate with each other via the wireless Ethernet network generated by each operating device, and are coupled to their host devices by wire, namely an Ethernet cable. Furthermore, the invention provides for a plurality of operational modes wherein each device  10  in a given network arrangement is configurable to operate as a wireless bridge, a wireless repeater and a wireless router. In the present invention, each device  10  forms a two-port node of a wireless network, each node having a wireless port and a wired port, where necessary, and, wherein a plurality of devices  10  may be interconnected to form a robust and wide-reaching wireless network over a virtually unlimited geographical area.  
      When a network generating device  10  is initially powered-up, it is programmed to transmit an RF addressing query over its wireless interface requesting the addresses of other nodes on the network. It also identifies itself as an extension of the network to all nodes detected in the initial query. Upon detection of another network generation device  10 , the new device requests an IP (Internet protocol) address and a gateway address. The contacted device  10 , if connected to an Internet gateway or a Dynamic Host Configuration Protocol (DHCP) server, supplies the requested information to the requesting node. If the contacted device is not connected to an Internet gateway or a DHCP, the contacted device simply acts as a wireless repeater, routing the request to a gateway or DHCP node.  
      If the initial addressing query fails to achieve network connectivity over the device  10  wireless port (antenna  20 ), the same address query is repeated over the device&#39;s wired port (Ethernet jack  230 ). Once these queries are conducted, each device  10  then requests routing tables from all detected nodes, generates a new routing table that includes itself, and broadcasts the new routing tables to its neighboring nodes, thereby including itself in the network. Finally, the device connects itself to its wired client, thereby functioning as either a host gateway, router, repeater or bridge as required for that specific node.  
      As can be readily seen, the presence of a plurality of network generating devices  10 , located at distances from each other sufficient to permit wireless Ethernet communications between adjacent devices, creates a wireless Ethernet infrastructure that is capable of acting as a wire line replacement. This system is particularly suitable for use in regions where wire line service is not readily available, or in urban locations where adding wire line communications functionality may be prohibitively expensive.  
      The network generating device  10  is capable of functioning as a router for its location in the overall network. Furthermore, the device utilizes carrier sense multiple access/collision avoidance (CSMA/CA) communications protocol, thereby enabling full duplex communications wherein data collision between Ethernet segments is nearly eliminated. Additionally, since the network generating device  10  employs dedicated transmit and receive antennae  20 , utilizing multiple broadcast frequencies, the system generated by the interconnection of a plurality of devices  10  is capable of both transmission and reception in full-duplex over multiple frequencies. Accordingly, the network created by the interconnection of a plurality of network generating devices  10  is not plagued by hidden node issues and is more robust as more devices  10  are added to the network.  
      In a yet further embodiment of the present invention, the network generating device  10  is capable of RF transmission and reception over a plurality of frequency bands. For example, the devices may transmit and receive at 2.45 GHz, 4.9-5.25 GHz, and 5.80 GHz. If transmission between neighboring nodes becomes garbled due to interference from external sources on one of the three operational frequencies, the device  10  transmits an outgoing signal at all three frequency ranges simultaneously, and receives incoming signals at all three frequency ranges simultaneously. This feature of the invention enables clear and error free data communications even when one frequency is unavailable or garbled due to electromagnetic interference or the like. In this embodiment of the invention, a plurality of dedicated antennae  20  may be employed, for example one antenna  20  for each operational frequency transmit and receive.  
      The present invention  10  is capable of production by modern manufacturing techniques wherein all components are located entirely on a single printed circuit board, thereby providing for an economical and compact network generating device that may readily be secured within a weatherproof enclosure  250 , that may further include a fastener or brackets necessary for mounting.  
      While the present invention has been shown and described herein in what are considered to be the preferred embodiments thereof, illustrating the results and advantages over the prior art obtained through the present invention, the invention is not limited to those specific embodiments. Thus, the forms of the invention shown and described herein are to be taken as illustrative only and other embodiments may be selected without departing from the scope of the present invention, as set forth in the claims appended hereto.