Abstract:
Methods and devices for operating a wireless network including redundant communication. Methods involving redundantly connected nodes are discussed including addressing methods and/or methods of creating groups for such redundant communication. The use of primary and secondary redundant connections is discussed. The inclusion of a redundant network in association with a non-redundant network such as a Zigbee® protocol network is discussed. Also, devices for implementing such methods are described.

Description:
FIELD  
       [0001]     The present invention is related to the field of wireless networks. More specifically, the present invention relates to methods of integrating multiple wireless networks together including wireless networks that are connected to a wired network.  
       BACKGROUND  
       [0002]     Wireless communication systems are coming into wide use for routing information from one or more locations to a destination. In some environments, multiple wireless systems may be used simultaneously.  FIG. 1  illustrates a first network having devices A and B, and a second network having devices C and D, operating in the same general vicinity. Some nodes A and C operate as infrastructure nodes and/or access points for each system. The infrastructure nodes may provide single hop communication (node-to-node) as well as multi-hop communication (communication directed to the base/destination node via other infrastructure nodes). The two networks are shown as being completely separate and non-cooperative. The configuration shown is spatially inefficient, as there are more “infrastructure” nodes than necessary given the space covered by the two systems. Further, when configuring communications within each network, the existence of the other network tends to create noise difficulties and further inefficiencies.  
         [0003]     New and reliable configurations for such systems are needed.  
       SUMMARY  
       [0004]     The present invention in several illustrative embodiments provides methods and devices for operating wireless networks in environments where multiple systems are in use. In an illustrative embodiment, an infrastructure node for wireless communication is configured to determine whether a communication it receives should be routed using a first network or a second network. The infrastructure node then routes data from the received communication appropriately. The infrastructure node may first determine whether the communication is a communication that the infrastructure node should handle.  
         [0005]     In another illustrative embodiment, a method of operating a wireless device includes determining which of a first and a second communication networks a received communication belongs to. The method may include first determining whether the communication is one which the wireless device should handle.  
         [0006]     In yet another illustrative embodiment, two networks, such as a mobile worker network and a sensor network, may operate in proximity to one another. An infrastructure node for use with both networks may include first and second communication devices, for example antennae, with one communication device adapted for communication with the mobile worker network and the other adapted for communication with the sensor network. In some such embodiments, one or more of the communication devices may be directional antennae. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  illustrates a multi-network environment;  
         [0008]      FIG. 2  illustrates an example wireless network having a base station, several infrastructure nodes, and several leaf nodes;  
         [0009]      FIGS. 3A-3B  illustrate data channel timelines showing separate ( FIG. 3A ) and integrated ( FIG. 3B ) networking use of data channels;  
         [0010]      FIG. 4  illustrates an infrastructure node operation for receiving and retransmitting data;  
         [0011]      FIGS. 5A-5C  illustrate the use of integrating wireless devices to build a system adapted for multi-network operation;  
         [0012]      FIG. 6A  shows an illustrative infrastructure node for integrating networks;  
         [0013]      FIG. 6B  shows an illustrative integrated network environment;  
         [0014]      FIG. 7  shows another illustrative integrated network environment; and  
         [0015]      FIG. 8  shows in functional block form an illustrative network integrating device. 
     
    
     DETAILED DESCRIPTION  
       [0016]     The following detailed description should be read with reference to the drawings. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention.  
         [0017]      FIG. 2  illustrates an example wireless network. Most, if not all, of the communicative couplings shown in  FIG. 2  are intended to indicate wireless communication. The network includes a base node  10  that is communicatively coupled to a number of infrastructure nodes (I-nodes, each indicated with an I). Some I-nodes  12 ,  20 ,  22  communicate directly with the base node  10 , while other I-nodes  14 ,  16 ,  18  send data through hops to reach base node  10 . The I-nodes may also be communicatively coupled to a number of leaf nodes (L-nodes, each indicated with an L).  
         [0018]     With respect to the illustrative base node  10 , the base node may be given various descriptive terms used in the art (for example, gateway, access point, etc.). For purposes herein, the base node  10  may be considered as a destination node for one or more networks, where a destination node serves as the destination for data transmitted within a network. The base node may also be connected to and communicating on a wired network; such a base node may be referred to as a gateway or access point.  
         [0019]     Certain methods and examples for operating a redundant system having the I-nodes and L-nodes of  FIG. 1  are shown and described in copending U.S. patent application Ser. No. 10/870,295, entitled WIRELESS COMMUNICATION SYSTEM WITH CHANNEL HOPPING AND REDUNDANT CONNECTIVITY, filed Jun. 17, 2004, and copending U.S. patent application Ser. No. 10/905,971, entitled WIRELESS ROUTING SYSTEMS AND METHODS, filed Jan. 28, 2005, the disclosures of which are incorporated herein by reference. For example, in some embodiments discussed in these patent applications, first and second non-overlapping redundant paths may be defined from the leaf nodes L to the base node  10 . Other networks, for example, networks under the Zigbee® protocol or otherwise in accordance with IEEE® 802.15.4, do not call for redundant connectivity.  
         [0020]     As noted above, the collection of I-nodes and L-nodes may be configured for redundant connectivity of the L-nodes. However, as further shown in  FIG. 1 , there may be additional devices that are neither I-nodes nor L-nodes. The illustrated system provides for interconnectivity of more than one type of network. More specifically, devices using the Zigbee® protocol terminology are shown. These include an FFD  30  directly communicating with the base node  10 . FFD  30  is shown also communicating with an RFD  32 . Additionally, an FFD  34  communicates with I-node  16  as well as RFD  36 . Finally, an RFD  38  is shown communicatively coupled to I-node  18 .  
         [0021]     If one of the networks shown in  FIG. 2  is a sensor network, for example, some or all of the L-nodes or RFDs may be battery powered devices, sometimes referred to as energy constrained devices (ECD). An ECD may have multiple modes including a low power sleep mode and an awake mode. While asleep, an ECD is out of communication with the rest of the network. While awake, an ECD is capable of transmitting messages. In some examples, an ECD can also receive messages from other wireless devices.  
         [0022]     Another set of terminology may consider the leaf nodes as examples of data sending nodes, while the infrastructure nodes are data relaying nodes. Likewise, an RFD may be a data sending node and an FFD may be a data relaying node. The terminology may be used to indicate that data sending nodes are nodes in which data originates, though the data sending nodes may not perform the task of receiving and retransmitting data addressed to other devices. Data relaying nodes may receive and retransmit data while also originating data when desired. The data sending nodes may also receive data that is addressed to them, including, for example, acknowledgements, addressing or scheduling information, etc.  
         [0023]     In some embodiments, the data sending nodes may be nodes which provide access to a network from another network. For example, a data sending node may receive data gathered in a different network and send data in a network as shown in  FIG. 2 . This may be useful, for example, when a wireless system is retrofitted to an existing facility having an older, local sensor network, with a data sending node used to move data from the old network onto a new network.  
         [0024]     One aspect of the system as shown in  FIG. 2  is the provision of more than one network within the same network system. For example, I-node  18  receives communications from I-nodes  12 ,  16 ,  22 , several L-nodes, and an RFD  38 . As such, I-node  18  is configured to receive, identify, filter, and/or handle various communications from each of these sources. Communications coming from the L-nodes may be treated differently from the communications coming from the RFD  38  and/or other I-nodes  12 ,  16 ,  22 . Further, if communication from FFD  34  is routed from I-node  16  to I-node  18 , this communication may also be treated differently from other messages received from I-node  16  by I-node  18 .  
         [0025]     The I-nodes  12 ,  16 ,  22  that combine functionality for the two networks may reduce the number of devices needed to provide infrastructure for the overall system. The I-nodes  12 ,  16 ,  22  may use mobile worker type networking (such as Bluetooth®, IEEE® 802.11 (b), or IEEE® 802.11 (g)) as well as other device networking (such as Honeywell®&#39;s XYR5000 systems, 802.15.2, or the redundant networking shown in U.S. patent application Ser. No. 10/870,295). The I-nodes  12 ,  16 ,  22  and/or the overall system may include smart-channel allocation to aid in the non-interfering coexistence of the two systems. For example, the I-nodes  12 ,  16 ,  22  may allow a mobile worker network operating using IEEE® 802.11 (g) to operate on non-overlapping channels  1  and  6  (as defined for the IEEE® 802.11 (g) protocol), while allowing a separate network, such as an industrial wireless sensor network, to operate on non-overlapping channel  11 , without interference.  
         [0026]     In some embodiments, the I-nodes  12 ,  16 ,  22  may include separate radio hardware for each of several systems. In some embodiments, the I-nodes  12 ,  16 ,  22  may include multiple transceivers. In another illustrative embodiment, one or more of the I-nodes  12 ,  16 ,  22  may include one or more software defined radios, allowing the I-nodes  12 ,  16 ,  22  to readily adapt to different networks using the same hardware.  
         [0027]      FIGS. 3A-3B  illustrate data channel timelines showing separate ( FIG. 3A ) and integrated ( FIG. 3B ) networking use of data channels. Referring to  FIG. 3A , a first timeline  50  is shown for a first network N 1 . For illustrative purposes, only four channels are used. It should be understood that in a real world environment there may be any number of channels, depending upon the actual devices and regional regulations. A second timeline  52  indicates channel usage by a second network N 2 . As shown in the two timelines  50 ,  52 , the networks use different channels at different times. A channel-hopping sequence may be used, for example. Because there are a limited number of channels available, eventually, as shown at  54  and  56 , both networks N 1 , N 2  may attempt to use the same channel at the same time, resulting in interference between the networks and, likely, causing delays in data movement and/or lost data. Further, the two networks may not be time coordinated. For example, one network may define longer frequency hops than the other, and/or the beginning/end of the frequency hops for each network may not line up, decreasing channel availability even more.  
         [0028]     Referring now to  FIG. 3B , if the two networks can be coordinated or integrated together, for example, using certain embodiments of the present invention, the use of channels by the networks N 1  and N 2  can be coordinated to avoid interference. In the timeline  60 , first blocks  64  indicate channel usage by one network, N 1 , and second blocks  66  indicate channel usage by the other network N 2 . Frequency hops can be coordinated because control over the networks N 1 , N 2  may come from one device or a small number of devices that participate in each network. Alternatively, control may be such that one network (for example, N 1 ) is subservient to the other network (N 2 ) and its frequency hop sequence or channel allocation may be defined in response to the dominant network.  
         [0029]      FIG. 3B  shows the two networks using overlapping channels in a non-overlapping schedule. In other embodiments, channels may be entirely allocated to one network. For example, if there are four channels ( 1 ,  2 ,  3 ,  4 ) available, channels  1  and  2  may be allocated to network N 1 , and channel  3  may be allocated to network N 2 , with channel  4  reserved for system level communication or future use. Decisions regarding channel allocation may be made in a suitable fashion, for example, online during operation, at initial deployment, or manually. The I-nodes in a network may collectively determine allocation, or a central channel allocation device may be used for this purpose either during operation or at initialization. In yet another embodiment, a configuration tool may be used to provide channel scheduling or allocation, or both. An illustrative configuration tool may be, for example, that of U.S. patent application Ser. No. 11/160,314, entitled WIRELESS APPLICATION INSTALLATION, CONFIGURATION AND MANAGEMENT TOOL, the disclosure of which is incorporated herein by reference.  
         [0030]      FIG. 4  shows illustrative node operation for receiving and retransmitting data. First, the infrastructure node receives data, as shown at  100 , which may include basic data checking methods such as parity checking. Next, it is determined whether the address of the data matches the medium access control (MAC) identifier, as shown at  102 . This MAC identifier is used for the first network. If query  102  yields a YES, the frame is directed to the first network, as noted at  104 , and routed to a control center, destination or base node via the first network, as shown at  106 . An ACK may be generated in a form suitable for the first network, as shown at  108 .  
         [0031]     If step  102  yields a NO, the frame is directed to determinations relative a second network, as shown at  110 . Next, it is determined whether the address of the data matches the second network ID, as shown at  112 . If not, the frame is discarded. Otherwise, the frame is sent to the second network, as shown at  114 , and routed to a control center, destination or base node for the second network, as indicated at  116 . An acknowledgement may be sent to the sending node from the second network, as shown at  118 .  
         [0032]     For the illustrative example shown in  FIG. 4 , the first network may be a mobile worker network, a Zigbee® protocol layer, a wired network, or any other suitable communication layer. The second network may use a different communications protocol than the first network, if desired. For example, if the first network is configured for a Zigbee® protocol, the second network may use, for example, a redundant network method such as one of the methods set out in copending U.S. patent application Ser. No. 10/870,295, which is incorporated herein by reference.  
         [0033]      FIGS. 5A-5C  illustrate the use of integrating wireless devices to build a system adapted for multi-network operation. The infrastructure for the illustrative network is shown in  FIG. 5A . Three infrastructure nodes  130 ,  132 ,  134  are shown. In the illustrative embodiment, there is two-way communication between the illustrative infrastructure nodes  130 ,  132 ,  134 , and one or more of the infrastructure nodes  130 ,  132 ,  134  may serve as an access point, gateway, or destination node for one or more networks. The infrastructure nodes  130 ,  132 ,  134  may engage in a sequence including discovery  142  and initialization  144  to set up communications with one another. In some embodiments, one or more of the infrastructure nodes  130 ,  132 ,  134  may be given authority to allocate communication channels and times for use in the system. In other embodiments, a specific controller device may be used, separate from the system, to perform such configuration steps. In yet other embodiments, a decentralized system may allow multiple infrastructure nodes  130 ,  132 ,  134  to perform allocation and scheduling tasks.  
         [0034]      FIG. 5B  is the same as  FIG. 5A  except that a first network that has devices A is also shown. A sequence of discovery  145 , initialization  147 , and, optionally, scheduling  149  may be performed. During discovery, one or more of the wireless devices in the system may send out discovery beacons to determine what other devices are in communication proximity. Discovery may occur through any suitable method, but when completed will often (though not necessarily) result in at least some system devices having data relating to the other devices in the system. For example, an I-node  134  may have data related to one of the devices A  136 , or the device A  136  may have data related to the I-node  134 , or both. Discovery  145  may occur at intervals, continuously, at random, or as needed.  
         [0035]     After discovery  145 , initialization may occur. During initialization  147 , the various devices in the system may become “associated” with one another for the purposes of communication. The word “associated” is used herein in its general sense and is not limited to a definition such as that of the Zigbee® protocol. This selection of communication routes may occur using decentralized or centralized methods. Next, communications within the system may be scheduled, as shown at  149 . The schedule may allocate certain times/channels of communication for certain purposes, depending upon the application. Not all communications in a system need to be scheduled, but some may be. For example, with an emergency sensor network, a schedule may be used to call for periodic communications to determine that individual sensors are still operational and/or to collect data from the sensors. When an emergency occurs (for example, a fire alarm is set off), an unscheduled communication may take place.  
         [0036]     Referring now to  FIG. 5C , a number of devices B are now shown, for example, device B at  138 . This second network having device B may also be subject to the steps of discovery  152 , initialization  154  and scheduling  156 . Discovery  152  and initialization  154  may be similar to discovery  145  discussed above. In some embodiments, discovery  152  and initialization  154  are performed instead of discovery  145  and initialization  147 , while in other embodiments, separate discovery and initialization steps may be performed, one for each network. In another embodiment, rather than going through steps  145 - 147 - 149  and then steps  152 - 154 - 156 , the steps may be integrated such that all of the discovery and/or initialization are performed prior to scheduling. In some cases, this may allow more efficient or optimized allocation of system resources.  
         [0037]     In an illustrative embodiment, the devices A make up a deployed industrial wireless sensor network, while the devices B are mobile workers and may use IEEE® 802.11 (b) or other suitable mobile protocols. In one such embodiment, the industrial wireless sensor network devices (devices A) have generally fixed or predictable locations (a sensor on an elevator, for example, has a non-fixed but predictable location). Thus, discovery is relatively simple for these devices, and initialization is not needed except in occasional circumstances, for example, when a new device is added or one of the devices A goes offline for whatever reason.  
         [0038]     However, maintenance of working communications connections with the mobile workers (devices B) may be more difficult because of their transient nature. For example, if device B at  138  is mobile, it may be initially associated with I-node  130  because it has the best communication connection thereto (best received signal strength or other indicator, for example). However, if device B at  138  moves to location  140 , it may be closer to I-node  152  and may have a better communication connection thereto. As the device B shown at  138  moves, however, the optimal scheduling and/or mapping of communications with device B  138  may change.  
         [0039]     In some embodiments a hybrid communications mapping/configuration method is used, combining both centralized and decentralized mapping. For example, in some embodiments, scheduling and mapping for fixed devices may be performed using a centralized mapping methodology, which may be updated periodically, or as needed. In the same embodiment, mapping for mobile devices may be performed using decentralized methods, which may be almost continuously updated. Several concepts relating to centralized and decentralized communication mapping and scheduling are discussed in copending U.S. patent application Ser. No. 10/905,971, entitled WIRELESS ROUTING SYSTEMS AND METHODS, the disclosure of which is incorporated herein by reference.  
         [0040]     In some embodiments, a first network makes use of scheduled communications while a second network makes use of transmitter initiated communications.  
         [0041]     It should be noted that, in some embodiments, single-transceiver infrastructure nodes may be used. In other embodiments, a multi-transceiver infrastructure node may be used, as shown in  FIGS. 6A, 6B  and  7 .  FIG. 6A  shows an illustrative infrastructure node for integrating networks. The infrastructure node  160  is shown in the illustrative embodiment as including both a first communication antenna  162  and a second communication antenna  164 . The antennae  162 ,  164  are coupled to first and second transceivers, which may be physically embodied in any suitable form. In some embodiments, one or both transceiver/antenna pairs are adapted for specific applications. In some embodiments, one or both transceiver/antenna pairs take the form of software defined radios.  
         [0042]     In some embodiments, the antennae  162 ,  164  and corresponding transceivers may each be adapted to receive or transmit on distinct frequencies. For example, antenna  162  may be tuned to frequency F 1  and antenna  164  may be tuned to frequency F 2  at a given time. By knowing associated network communications protocols, it may be determined that a message received on F 1  by antenna  162  was generated by a first network, most likely, while a message received on F 2  by antenna  164  likely comes from a second network. The data content (addressing, FCS, etc.) of each message may be further used to determine whether each message is from a device in one or the other network.  
         [0043]      FIG. 6B  shows an illustrative integrated network environment. The network shown in  FIG. 6B  includes a first infrastructure node  170  and a second infrastructure node  172 . A mobile worker is shown at  174 , and communicates wirelessly with the first infrastructure node by communication with a first antenna  176 . An additional mobile worker is also shown in communication with the first antenna  176  on the first infrastructure node  170 . Any of a number of methods, for example, code or time division, may be used to allow communication with each of the mobile workers using the first antenna  176 . A number of sensors, including sensor  178 , are also shown in communication with a second antenna  180  on the first infrastructure node  180 .  
         [0044]     The second infrastructure node  172  communicates with a mobile worker  182  using a first antenna  184 , and with a sensor  186  via a second antenna  188 . The second infrastructure node  172  may be a base node or destination node as well, as it is shown connected to wired network WN. In an illustrative embodiment, the plural transceivers allow each infrastructure node  170 ,  172  to use more than one channel for communication at any given time. In addition to simply increasing communication capacity, the inclusion of multiple transceivers on each infrastructure node  170 ,  172  also allows for coordination of two wireless systems operating in the same space, while still allowing each of the two systems to operate independent of the other. For example, the mobile workers including mobile workers  174 ,  182  may communicate using a first network with first protocols, and the sensors including sensors  178 ,  186  shown in  FIG. 6B  may communicate in a second network using second protocols. The networks, as illustrated above in  FIG. 3B , can be coordinated because the infrastructures for each network are managed together.  
         [0045]     In the embodiment of  FIG. 6B , a communication plan that may include mapping and/or scheduling of transmissions in a first network having the sensors  178 ,  186  may operate without interfering with a communication plan including mapping and/or scheduling of transmissions for a second network having the mobile workers  174 ,  182 . Other network types may be used in additional embodiments.  
         [0046]      FIG. 7  shows another illustrative integrated network environment. In this environment, a first infrastructure node  200  and a second infrastructure node  202  are again equipped with multiple transceivers. The first infrastructure node includes a first antenna  204  and a directional antenna  206 , with the directional antenna communicating with sensor  208  using a directional beam. The second infrastructure node  202  communicates using a directional antenna  212  and another antenna  214 . Again, the directional antenna  212  is used to communicate with sensors.  
         [0047]     The illustrative system of  FIG. 7  may make use of the non-directional antennae  204 ,  214  to communicate with one or more mobile workers  210 ,  218 . As indicated by their name, the workers may be “mobile” and move throughout the available space. Thus, the non-directional antennae  204 ,  214  may be disposed to provide coverage for a given area/space. Meanwhile, the sensors, including sensor  208 , may be at fixed locations. For example, if the sensors are thermostats, smoke alarms or motion detectors, these devices may be placed in a facility at desired locations and left in place. By using directional antennae  206 ,  212 , the amount of noise created by communications with the sensors is reduced to a lesser area than would occur with non-directional antennae. The directional antennae  206 ,  212  have been shown as phased array antennae, though any suitable directional antennae may be used.  
         [0048]      FIG. 8  shows in functional block form an illustrative integrating device. The device  250  includes a variety of wired/wireless communication modules shown at  252  that may be used for a first set of communications via suitable media as shown at  254 . The device  250  may also include a set of wireless communications shown at  256  that operate on the same device as the wired/wireless communication modules of  252 . The wireless communications  256  may occur at suitable frequencies, as nodded at  258 . Various components  260  are also shown.  
         [0049]     In addition to the above embodiments, further systems, such as third, fourth, or more wireless or wired communication systems may be further incorporated. Certain of the devices in the network may be further adapted to operate with third and more networks.  
         [0050]     Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departures in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.