Abstract:
The present invention shows, among other things, how to build rapidly deployable ad hoc networks from a combination of wired communications components with wireless communication components. The resulting kind of network is entirely novel and has a number of advantages over existing wireless-only techniques. Namely, it combines automatic robustness in the face of errors and network destruction with the high speed and great resistance to jamming of wired network.

Description:
DESCRIPTION OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to methods and systems for facilitating rapid deployment of ad hoc networks.  
         [0003]     2. Description of Related Art  
         [0004]     Certain situations, such as military battlefields or scenes of disaster relief, require rapid deployment of communication networks. Rapidly deployed communication networks are referred to as “ad hoc networks” because they do not rely on a pre-established infrastructure. Each user participating in an ad hoc network forward data packets as needed to ensure that the packets are delivered from a source to a destination in the network.  
         [0005]     Ad hoc networks have generally relied entirely upon wireless networks because wireless elements in the wireless network may be easily emplaced. However, wireless networks usually have low throughput and are susceptible to jamming and accidental interference. In contrast, wired networks have high throughput and great resistance to jamming because they confine signals within a waveguide, such as fiber optic strands or metallic wires. However such wired networks can not be rapidly deployed in an ad hoc manner in redundant meshes. Hence a form of ad hoc networking that could self-organize, route around failures, and employ both wired and wireless links would be advantageous.  
       SUMMARY OF THE INVENTION  
       [0006]     Systems and methods consistent with the present invention provide for the creation of ad hoc networks by combining wireless elements and wired elements. Both elements may be rapidly deployed using unconventional means, such as missiles and helicopters, or more conventional means, such as trucks. The invention combines advantages of wireless networks, such as flexibility, rapid deployment and robustness in the face of errors and network destruction, with the high speed and great resistance to jamming of wired networks.  
         [0007]     One exemplary aspect of the present invention may be a rapidly deployable ad-hoc network. The network may include a first transceiver, a second transceiver connected to the first transceiver by a wired link to facilitate communication between the first transceiver and the second transceiver when necessary, and a wireless link established when necessary to facilitate communication between the first transceiver and the second transceiver. A routing protocol may dynamically determine a path selected from the wired link and the wireless link to communicate packets between the first transceiver and the second transceiver adjusting accordingly based on an available quality of service using at least one of the wired link and the wireless link.  
         [0008]     A second exemplary aspect of the present invention may be a rapidly deploying ad-hoc network. The network may include a plurality of transceivers, a plurality of wired links connecting some of the transceivers to facilitate communication between the connected transceivers and a plurality of wireless links, each wireless link established when necessary to facilitate communication between selected transceivers. A routing protocol may dynamically determine a path selected from the wired and the wireless links to communicate packets between transceivers adjusting accordingly based on a quality of service using the wired links and the wireless links.  
         [0009]     A third exemplary aspect of the present invention may be a method for communicating packets in a rapidly deployed ad-hoc network. The method may include providing a wired link to facilitate communication between a first transceiver and a second transceiver when necessary and providing a wireless link when necessary to facilitate communication between the first transceiver and the second transceiver. A routing protocol may dynamically determine a path selected from the wired link and the wireless link to communicate packets between the first transceiver and the second transceiver adjusting accordingly based on a quality of service using at least one of the wired link and the wireless link.  
         [0010]     A fourth exemplary aspect of the present invention may be a method of communicating packets in a rapidly deployed ad-hoc network. The method may include providing a plurality of wired links to facilitate communication between a set of transceivers selected from a plurality of transceivers when necessary and providing a plurality of wireless links when necessary to facilitate communication between selected transceivers. The routing protocol may dynamically determine a path selected from the wired and wireless links to communicate packets between transceivers adjusting accordingly based on any disruptions in communication using wired and wireless links.  
         [0011]     A fifth exemplary aspect of the present invention may be a device for use in an ad-hoc network. The device may include a processor, memory, means for facilitating communication using at least one wired link when necessary, and means for facilitating communication using at least one wireless link when necessary. A routing protocol may dynamically determine a path including at least one of the wired link and the wireless link to communicate packets adjusting accordingly based on a quality of service using at least one of the wired link and the wireless link.  
         [0012]     A sixth exemplary aspect of the invention may include a system. The system may include a means for specifying a missile destination and a means for launching a missile traveling substantially toward the missile destination. The missile may be connected to a wired link and communication between devices may be facilitated via the wired link after the missile and a transceiver connected to the wired link has been launched.  
         [0013]     Additional aspects of the invention are set forth in the description which follow, and in part are obvious from the description, or may be learned by practice of methods, systems, and articles of manufacturer consistent with features of the present invention. The aspects of the invention may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is understood that both the foregoing description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention and together with the description, serve to explain the principles of the invention. In the drawings,  
         [0015]      FIG. 1  illustrates a first exemplary form of building blocks for an ad hoc network in which methods and systems consistent with features and principles of the present invention may be implemented;  
         [0016]      FIG. 2  illustrates an exemplary means for deploying a network consistent with features and principles of the present invention;  
         [0017]      FIG. 3  illustrates a first exemplary ad hoc network in which methods and systems consistent with features and principles of the present invention may be implemented;  
         [0018]      FIG. 4  illustrates an abstract network graph of the first exemplary ad hoc network consistent with features and principles of the present invention;  
         [0019]      FIG. 5  illustrates a second exemplary form of building blocks for an ad hoc network in which methods and systems consistent with features and principles of the present invention may be implemented;  
         [0020]      FIG. 6  illustrates an abstract network graph of a second exemplary ad hoc network consistent with the features and principles of the present invention;  
         [0021]      FIG. 7  illustrates the second exemplary ad hoc network in which methods and systems consistent with features and principles of the present invention may be implemented;  
         [0022]      FIG. 8  illustrates an exemplary environment in which second form building blocks may exploit rich connectivity for network robustness consistent with features and principles of the present invention;  
         [0023]      FIG. 9  illustrates an exemplary environment in which an ad hoc network exploits rich connectivity for network robustness consistent with features and principles of the present invention;  
         [0024]      FIG. 10A  illustrates an exemplary hardware schematic of wireless transceivers consistent with features and principles of the present invention; and  
         [0025]      FIG. 10B  illustrates another exemplary hardware schematic of wireless transceivers consistent with features and principles of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0026]     Systems and methods consistent with the present invention provide for the creation of ad hoc networks by combining wireless elements and wired elements. The wireless and wired elements are self-organized to facilitate communication between devices over the ad hoc network. Self-organization involves the use of routing protocols that determine network paths for the communication. Self-organizing networks do not require substantial external organization such as those provided by pre-existing infrastructure in determining the network paths. Rather, ad hoc networks may be rapidly deployed without substantial regard to pre-existing infrastructure. The ad hoc networks may further configure themselves to route around disruptions or unacceptable quality in communication using both the wireless and wired elements.  
         [0027]     Reference is now made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts.  
         [0028]      FIG. 1  illustrates a first exemplary form of the basic building blocks for an ad hoc network  100  in which methods and systems consistent with features and principles of the present invention may be implemented.  FIG. 1  includes an external network  101 , an external router  102 , an external wire  103 , a wireless transceiver  104 , a first fiber-optic strand  105 , a fiber-optic cable  106 , a second fiber-optic strand  107 , a second wireless transceiver  108 , two wireless communication links  109 , and two wireless devices  110 . External wire  103  may physically and communicably link the external router  102  and the wireless transceiver  104  to form a wired communication link. Wireless devices  110  and the second wireless transceiver  108  may be communicably linked by the wireless communication links  109 . Wireless communication links may include a radio frequency link, infrared link, acoustic link, or any other communication link without wires. Fiber-optic cable  106  may form another wired communication link between the wireless transceivers  104  and  108 . Wireless transceivers  104  and  108  may contain routers (not shown). The routers may act as network bridges for the wireless transceivers  104  and  108  and the fiber-optic cable  106 .  
         [0029]     Fiber-optic cable  106  may contain two wires, fiber-optic strands  105  and  107 . One fiber-optic strand may be used for communication in one direction, and the other fiber-optic strand may be used for communication in the opposite direction. In an alternative configuration (not shown) a single fiber-optic or other physical communication link strand may be used for round-trip communication between the transceivers.  
         [0030]     The routers in the wireless transceivers  104  and  108  at each end of the fiber-optic cable  106  may contain an optical transmitter (not shown) attached to one fiber-optic strand and an optical receiver (not shown) attached to the other fiber-optic strand. Thus when one router transmits over the fiber-optic cable  106 , the other router may receive over the fiber-optic cable  106 . Commercial examples in the art illustrating simultaneous transmission and reception may include fiber-optic telephony networks.  
         [0031]     Each wireless transceiver  104  and  108  also may contain its own self-contained power supply such as a fuel cell, battery, solar power converter, etc. (not shown). A number of such wireless transceivers  104  and  108  and fiber cables  106  may be deployed in order to form an ad hoc network for a region.  
         [0032]     The use of the fiber-optic cable  106  in the building block  100  is exemplary and does not preclude the use of other wire medium, such as metal wire, to create physical communication links between wireless transceivers  104  and  108 .  
         [0033]      FIG. 2  illustrates an exemplary means for deploying a network  200  consistent with features and principles of the present invention.  FIG. 2  includes three launching points (LP)  201 - 203 , three trajectories  204 - 206 , three fiber-optic cables  207 - 209 , and three impact points (IP)  210 - 212 . Missiles or other similar devices (not shown) may be fired from the launching points  201 - 203 . The missiles travel along their respective missile trajectories  204 - 206  to land at their respective impact points  210 - 212 . As the missiles move along their missile trajectories  204 - 206 , they may deploy fiber-optic cables  207 - 209 . Wireless transceivers may be attached at the ends of the fiber-optic cables  207 - 209  after the missiles land at their impact zones  210 - 212  to form an ad hoc network. The wireless transceivers may also be pre-attached to the fiber-optic cables  207 - 209  and deployed by the missiles.  
         [0034]     Examples of situations where fiber-optic cables may be attached to missiles exist and include Tube-launched, Optically-tracked, and Wire-guided (TOW) anti-tank missiles. A TOW missile requires a gunner to spot such as an enemy tank through a sight. The gunner may fire the missile from a tube similar to a bazooka. A pair of thin wires may be connected to the rear of the missile and spool out from the launching tube. These wires may be used to send signals to control the missile&#39;s fins and thus direction of flight. However, the wires are not used to form a network.  
         [0035]     Further exemplary means of rapidly deploying wiring may include deploying wire from air-based, sea-based, land-based, and space-based vehicles, trucks, submarines, planes, satellites, and helicopters as they maneuver over a region and/or by human hand. Rapid deployment may include laying wire without regard to obstacles or intent to use existing infrastructure. Means of deploying wire may simply lay down the wire across a landscape. The wire may lie across ditches, over bushes, or hang from buildings and trees along its path.  
         [0036]      FIG. 3  illustrates how a number of deployed wires  313 - 316  may be organized into a first exemplary ad hoc network  300  in which methods and systems consistent with features and principles of the present invention may be implemented. As shown in  FIG. 3 , the exemplary ad hoc network  300  may be formed by a number of simple form ad hoc networks like the one illustrated in  FIG. 1 . The ad hoc network  300  may include eight wireless transceivers  301 - 308 , an external router  309 , an external network  310 , two wireless devices  311 - 312 , four deployed wires  313 - 316 , wireless communication links  318 - 323 , and wireless device communication links  317  and  324 . The wireless transceivers  301 - 304  may have wired communication links over the wires  313 - 316  to the wireless transceivers  305 ,  307 ,  306 , and  308 , respectively. The first wireless device  311  may be communicably linked with transceiver A  301  by the wireless device communication link  317 . Transceiver A  301  may be communicably linked with transceiver H  308  by the wireless communication link  318 . Transceiver G  307  may be communicably linked with transceivers H  308  and F  306  by wireless communication links  319 - 320 , respectively. Transceiver B  302  may be communicably linked with transceiver C  303  by the wireless communication link  321 . Transceiver D  304  may be communicably linked with transceiver C  303  and E  305  by wireless communication links  322  and  323 , respectively. The second wireless device  312  may be communicably linked with transceiver D  304  by the wireless device communication link  324 .  
         [0037]      FIG. 4  illustrates the corresponding abstract network graph  400  for the exemplary ad hoc network  300  in  FIG. 3 . In the network graph  400 , the solid lines indicate wired communication links  313 - 316  and  325 , and the dashed lines  317 - 324  indicate wireless or wireless device communication links. In essence, the set of wireless transceivers  301 - 308  may form an ad hoc network for communication between the devices  311 - 312  that access the ad hoc network via wireless device communication links  317  and  324 . When the two devices  311 - 312  communicate, a network path may be formed. A network path may be a combination of wireless and/or wired communications links in the ad hoc network that communicably links the two devices. For example, a network path comprising wireless device communication link  317 , wired communication link  313 , wireless communication link  323 , and wireless device communication link  324  may be used by the devices  311  and  312  to communicate with each other.  
         [0038]     The exemplary ad hoc network  300  may run under the Internet Protocol (IP) suite, but it may also run under an Asynchronous Transmission Mode (ATM) network protocol or any form of network protocol. Network paths through this network may be self-organized and computed by a routing protocol such as Link-State Routing (also called Shortest Path First), distance vector routing, Mobile Ad-Hoc Network (MANET) routing (such as Ad-Hoc On-Demand Distance Vector (AODV) or Dynamic Source Routing (DSR)), or any other routing protocol. Since the network graph  400  resembles that of many other forms of networks known in the art, all kinds of routing technology may be employed.  
         [0039]     For example, the exemplary ad hoc network  300  in  FIG. 3  may be running a Shortest Path First (SPF) routing protocol. Wireless device  311  may seek to communicate with wireless device  312  in  FIG. 3 . Under the SPF routing protocol, the ad hoc network  300  self-organizes to facilitate communication between the wireless devices  311 - 312  by dynamically determining a shortest network path consisting of wired and wireless communication links. The SPF routing protocol may organize a shortest network path comprising the wireless device communication link  317 , the wired communication link  316 , the wireless communication link  323 , and the wireless device communication link  324 . However, if the quality of communication over the network path is unacceptable, then the routing protocol may organize the next shortest network path. The next shortest network path may have more acceptable quality of communication and may comprise of the wireless device communication links  317  and  324 , the wireless communication links  318 - 320  and  322 , and the wired communication link  315 .  
         [0040]     In the above example, self-organization includes the control and determination of network paths without substantial external organization such as those provided by pre-existing infrastructure. The ad hoc network  300  controls and determines the paths and alternative paths as dictated by the routing protocols to provide acceptable quality of communication. Control over the network paths may reside in one component of the ad hoc network  300  or it may be distributed over all the components of the ad hoc network  300 . One of the transceivers  301 - 308  may be a master node and coordinate all the networks paths or some of the transceivers may co-operatively determine the network paths.  
         [0041]     In many ways, the wire communication links  313 - 316  are vastly superior to the wireless communication links  318 - 323 . They are much faster, resistant to jamming, and generally require less power. Thus these wired communication links  313 - 316  may be preferred over the wireless communication links  318 - 323  when forming a network path. This preference may be accommodated in most routing protocols by setting link metrics in the routing protocols accordingly. For example, wire communication links  313 - 316  may be assigned very low link metrics and wireless communication links  318 - 323  may be assigned very high link metrics. Therefore, a resistance of network paths that use wireless communication links may be much higher than those that use wired communication links. The protocol may choose the network path of least resistance. The chosen network path across the ad hoc network may consist of many different transitions from wireless to wired communication links and vice versa. The exemplary ad hoc network  300  in  FIG. 3  may handle many deployment scenarios. However some scenarios may require more wireless transceivers. For example, in the event that wires break or a great deal of terrain needs to be covered and the wired transceivers do not lie within wireless range of each other, additional wireless transceivers may be needed to bridge the break or cover the terrain. Therefore, another exemplary form of the invention may include a series of wireless transceivers along the length of the fiber cable.  
         [0042]      FIG. 5  illustrates a second exemplary form of building blocks for an ad hoc network  500  in which methods and systems consistent with features and principles of the present invention may be implemented. As shown,  FIG. 5  includes five wireless transceivers  501 - 505 , a wire cable  506  with two strands, and three tap connections  507 - 509 . The intermediate wireless transceivers  502 - 504  may create a daisy chain along the wire cable  506  connecting the first and last wireless transceivers  501  and  505 . The first wireless transceiver  501  may communicate directly with the next wireless transceiver  502 , which in turn may communicate with the next wireless transceiver  503 , and may continue so forth to the last wireless transceiver  505 . When all wireless transceivers  501 - 505  have power, a packet (not shown) may proceed along the wire cable  506 , hop by hop, retransmitted by each wireless transceiver. The packet may be information represented in a form communicable over the wire cable  506  and wireless transceivers  501 - 505 . This daisy chain form of building block  500  may require each wireless transceiver  501 - 505  to receive and retransmit the packet to the next wireless transceiver  501 - 505 . If one of the wireless transceivers  501 - 505  in the daisy chain is not operational, then the packet may not be communicated passed the non-operational wireless transceiver.  
         [0043]     An alternate embodiment may employ Passive Optical Networking (PON) versus retransmitting by each wireless transceiver. In PON, the wire cable  506  may be a fiber-optic cable and the wireless transceivers  502 - 504  in the middle may tap into the fiber-optic cable using passive techniques. The various wireless transceivers  501 - 505  may employ channel access arbitration to decide when and which wireless transceiver  501 - 505  transmits a packet and use channel-level addressing to determine which wireless transceiver  501 - 505  receives any transmitted packets on the wire cable  506 . The alternate embodiment may not require the wireless transceivers  501 - 505  to always retransmit the packet.  
         [0044]      FIG. 6  illustrates an abstract network graph  600  of a second exemplary ad hoc network consistent with the features and principles of the present invention. In addition to the elements illustrated in  FIG. 4 ,  FIG. 6  includes five intermediate wireless transceivers  601 - 605  and five more wireless connections  606 - 610 . The first two intermediate transceivers I 1   601  and I 2   602  may be situated along the wire cable  313  connecting transceiver A  301  and transceiver E  305 . The third intermediate transceiver I 3   603  may be situated along the wire cable  314  connecting transceiver G  307  and transceiver B  302 . The fourth intermediate transceiver I 4   604  may be situated along the wire cable  316  between transceivers H  308  and D  304 . The fifth intermediate transceiver I 5   605  may be situated along the wire cable  315  between transceivers F  306  and C  303 .  
         [0045]      FIG. 7  illustrates the second exemplary ad hoc network  700  corresponding to the abstract network diagram  600  in which methods and systems consistent with features and principles of the present invention may be implemented. The intermediate wireless transceivers  601 - 605  may increase the richness of connectivity in the ad hoc network  700  with the addition of wireless communication links  606 - 610 . Richness in connectivity may be the total number of wired and wireless communication links. Higher richness in connectivity may allow the ad hoc network  700  in  FIG. 7  to have more potential network paths than the ad hoc network  300  in  FIG. 3 .  
         [0046]      FIG. 8  illustrates an exemplary environment in which a building block  800  may exploit rich connectivity for network robustness consistent with features and principles of the present invention. Block  800  may include two wireless transceivers  801  and  806 , four intermediate wireless transceivers  802 - 805 , a wire cable  807 , two wireless communication links  810  and  811 , and two breaks  808  and  809  in the wire cable  807 . The wire cable  807  may form a wired communication link between the wireless transceivers  801  and  806 . The intermediate wireless transceivers  802 - 805  may tap into the wire cable  807  using passive techniques. The breaks  808  and  809  in the wire cable  807  may prevent wireless transceivers  801  and  806  from communicating through a network path consisting only of the wire communication link over the wired cable  807 . However, the rich connectivity created by the intermediate wireless transceiver  802 - 804  may allow communication between the wireless transceivers  801  and  806  using an alternate network path including the wireless communication links  810  and  811  and wired communication links over portions of the wired cable  807  to circumvent the breaks  808  and  809 .  
         [0047]      FIG. 9  illustrates an exemplary environment in which an ad hoc network  900  may exploit rich connectivity for highly robust connectivity consistent with features and principles of the present invention. The ad hoc network  900  may include four wireless transceivers  901 ,  905 ,  906 , and  911 , seven intermediate wireless transceivers  902 - 904  and  907 - 910 , two wire cables  917  and  918 , breaks  916  in the wireless cables  917  and  918 , and four wireless communication links  912 - 915 . The breaks  916  may prevent wireless transceiver A  901  from communicating with wireless transceiver B using a network path comprising of only a wired communication link over the wired cable  917 . However, another network path comprising of the wireless communication links  912 - 915  and wired communication links over portions of the wired cables  917  and  918  without breaks  916  may allow the wireless transceivers  901  and  905  to communicate.  
         [0048]      FIG. 10A  illustrates an exemplary hardware schematic  1000  of a wireless transceiver consistent with features and principles of the present invention. The schematic  1000  may be suitable for wireless transceivers attached at ends of fiber-optic cables or for intermediate wireless transceivers that may be daisy chained as illustrated in  FIG. 5 . The schematic  1000  may include central processing unit (CPU)  1001 , random-access memory (RAM)  1002 , wireless transceiver antenna  1003 , flash memory  1004 , network interfaces  1005 , optical transceiver  1006 , power supply  1007 , bus  1008 , fiber-optic strands  1009 , and external network connection  1010 . The CPU  1001 , RAM  1002 , wireless transceiver antenna  1003 , flash memory  1004 , network interfaces  1005 , and optical transceiver  1006  may communicate using the bus  1008 . The power supply  1007  may provide energy for the components  1001 - 1006  to perform their functions. The optical transceiver  1006  may transmit and receive packets of information over the fiber-optic strands  1009 .  
         [0049]     Wireless and intermediate wireless transceiver may contain one or more network interfaces  1005  for a wired communication link over an external network connection  1010  to an external network (not shown). Some exemplary network interfaces may be Ethernet transceivers, Asynchronous Transfer Mode (ATM) transceivers, serial lines, or any other conventional means known in the art. The network interface  1005  may also be used to connect two wireless transceivers, thus forming a wired communication link between the two wireless transceivers.  
         [0050]      FIG. 10B  illustrates another exemplary hardware schematic  1011  of wireless transceivers consistent with features and principles of the present invention. The schematic  1011  in  FIG. 10B  is the same as the schematic  1000  in  FIG. 10A  with one exception. The exception is that in place of the optical transceiver  1006  in  FIG. 10A , the schematic  1011  in  FIG. 10B  may have a passive optical network transceiver  1012 . This schematic  1011  may be suitable for use in an ad hoc network employing PON as described above.  
         [0051]     In the foregoing description, various features are grouped together in various embodiments for purposes of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects may lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this description, with each claim standing on its own as a separate embodiment of the invention.