The present document relates to self-governing wireless communications systems and, in one example, to a wireless network of node-to-node communications for use on railway lines in remote regions where other forms of wireless communication are unavailable.
The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
Wireless mesh networks have been used for railway video surveillance, on-board systems communication, and troubleshooting. Remote areas pose a challenge for traditional networks to avoid the perils and uncertainties of gaps in cellular or other long-range communication networks.
A communications system is disclosed comprising: a plurality of nodes distributed within a geographical area, each of the plurality of nodes being in communication with one or more of the other of the plurality of nodes to collectively form at least a partially-connected wireless mesh network; and each of the plurality of nodes having: a node processor; a battery; a connection to a power source; a short-range transceiver for short-range communications between nodes of the plurality of nodes; and a long-range transceiver for long-range communication with a long-range network; and in which each of the plurality of nodes are configured to dynamically assign and use one or more of the plurality of nodes as a border router.
A method is disclosed comprising: using a plurality of nodes to communicate with each other in a partially-connected mesh network and dynamically assign one or more of the plurality of nodes as a border router, in which the plurality of nodes are distributed within a geographical area; and using the border router to relay communications from the plurality of nodes through the long-range network.
A communications system, according to the present disclosure, has a plurality of trackside nodes, arranged alongside a railway line, each in communication with at least one other of the plurality of nodes. A plurality of gateway routers installed periodically adjacent to the railway line, to facilitate communication between one or more nodes and a long-range network.
In another embodiment, each node has a first wireless transceiver for short distance communication and a second wireless transceiver for long distance communication. The system software gathers information on performance factors to evaluate each node and determine which nodes will communicate both with other nearby nodes and with the long-range network, in place of the plurality of gateway routers.
In another embodiment, the performance factors are one or more factors selected from the group consisting of: battery performance, number of other nodes in communication range, cellular signal strength, number of other nearby candidate uplink nodes, and distance to the nearest suitable candidate uplink node.
In another embodiment, the first transceiver is a low frequency radio transceiver, for example an IEEE™ 802.15.4E 2.4 GHz wireless transceiver, a 2GFSK transceiver or a device that operates using other protocols.
In various embodiments, there may be included any one or more of the following features: The plurality of nodes comprise one or more gateway routers. The one or more gateway routers are characterized by superiority relative to the other of the plurality of nodes, of one or more of battery performance, long-range link quality, power source capacity, power source permanence, and a wired connection to the long-range network. In a first mode, each of the plurality of nodes assign and use one or more gateway routers as the border router in preference to the other of the plurality of nodes. In a second mode, each of the plurality of nodes assign and use another of the plurality of nodes as a border router when a ranking of the gateway router drops below a predetermined threshold or a ranking of the another of the plurality of nodes. Each of the plurality of nodes are configured to dynamically assign a border router for the node based on rankings dynamically assigned to each of the plurality of nodes. A ranking of each node is based on one or more of the following performance characteristics: a battery capacity, battery performance, available charging capacity, long-range link quality, microcontroller unit (MCU) utilization, number of other nodes in communication range with the node, number of other nearby candidate border routers, distance to the nearest suitable candidate border router, long-range network load, and short-range bandwidth. The ranking of each node is based on at least battery capacity, available charging capacity, and long-range link quality. Each of the plurality of nodes are configured to broadcast, to other of the plurality of nodes, performance characteristics of the node at periodic intervals or as a result of a change in performance characteristics. Each of the plurality of nodes are configured to self-rank and broadcast a self-ranking for the node to other of the plurality of nodes. Each of the plurality of nodes are configured to dynamically assign and use one or more of the plurality of nodes as a border router based on the rankings provided by each of the plurality of nodes and a short-range link quality to each of the plurality of nodes. There are a plurality of border routers available for a node; and the plurality of nodes are configured to failover to other of the plurality of border routers when a first of the plurality of border routers is instructed, and fails, to send a long-range transmission through the long-range network. In the event of a border router being instructed, and failing, to send data through the long-range network, one or more of the plurality of nodes storing and subsequently re-attempting to send or instruct the sending of the data. The power source of one or more of the plurality of nodes comprises a low-watt power source. The power source has an average energy production capacity of 15 W/hr or less daily. The power source comprises a solar panel. Each of the plurality of nodes comprises a housing and is mounted above-ground on a pole. The long-range wireless network comprises one or more of the internet, a cellular network, and a satellite network. The geographical area comprises a transport corridor. The transport corridor comprises a railway track for a train. The plurality of nodes are configured to maintain a train on the railway track in continuous communication with the long-range wireless network. The geographical area comprises a remote geographical area with portions or the entirety of which being out of contact with a cellular network other than via one or more border routers. The long-range transceiver comprises one or more of: a cellular transceiver, a satellite transceiver, a broadcast radio transceiver, and a microwave transceiver. The short-range transceiver comprises one or more of a low frequency radio transceiver, an infrared transceiver, a Bluetooth transceiver, a Wi-Fi transceiver, and a mesh network transceiver. The short-range transceiver comprises a low frequency radio transceiver, such as a 2.4 GHz or 915 MHz wireless transceiver. A back-end system comprising a server processor connected to receive and transmit communications from and to, respectively, the plurality of nodes via the long-range network. The server processor is connected to serve and relay communications information from the plurality of nodes to third parties via the long-range network. A plurality of sensors connected to provide information to the plurality of nodes. The plurality of sensors are configured to sense and provide information on one or more of motion, temperature, vibration, tilt, rail or corridor integrity, seismic activity, humidity, water levels, weather, flooding, proximity, obstacle, wildlife, sound and visual elements. The plurality of nodes comprise one or more gateway routers; in a first mode, each of the plurality of nodes assign and use one or more gateway routers as the border router in preference to the other of the plurality of nodes; and in a second mode, each of the plurality of nodes assign and use another of the plurality of nodes as a border router when a ranking of the gateway router drops below a predetermined threshold or a ranking of the another of the plurality of nodes. E each of the plurality of nodes are configured to dynamically assign a border router for the node based on rankings dynamically assigned to each of the plurality of nodes. Each of the plurality of nodes broadcasting, to other of the plurality of nodes, performance characteristics of the node at periodic intervals or as a result of a change in performance characteristics. Each of the plurality of nodes self-ranking itself and broadcasting a self-ranking for the node to other of the plurality of nodes. At one of the plurality of nodes: assigning one of the other of the plurality of nodes as a border router based on the rankings provided by each of the plurality of nodes and a short-range link quality to each of the plurality of nodes; and transmitting a message to the border router. There are a plurality of border routers available for a node, and further comprising: attempting to transmit data by one of the plurality of border routers; and in the event of failure, attempting to transmit data by subsequent of the plurality of border routers. In the event of no other suitable border router being located or all possible border routers failing to transmit the data, storing and subsequently re-attempting to send or instruct the sending of the data. The plurality of nodes cooperate to collectively assign rankings to each node. The plurality of nodes collectively form a self-healing wireless mesh network. The low-watt power source has a wattage of 50 watts or less. Transmitting a message off-network through the long-range network via a border router.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the subject matter of the present disclosure. These and other aspects of the device and method are set out in the claims.
Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which:
Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.
Remote geographical areas exist where gaps in cellular or satellite networks (or other long-range networks) make long-range communications difficult or impossible. Many industrial operations, such as rail, mining, pipeline, harvesting, and others, are carried out in remote geographical areas, such as remote forests, mountain ranges, waterways, plains, or other topographies. Communications in such cases may be difficult, expensive, and time-delayed, and in some cases impossible. There are advantages in being able to permit real-time and/or continuous communications with remote or far-away areas, for example, the ability the monitor and respond quickly to changing conditions, weather, situations, and emergencies, and the ability to maximize efficiency of operations. Remote train lines are no exception to these issues. Many remote train lines are cut off from traditional communication lines, resulting in situations where a passing train may be out of communications with headquarters for an extended period of time. In such a situation, any major (such as an emergency, for example a derailment) or even minor (such as a rail blockage or weather obstruction) occurrence may be difficult to detect, trouble-shoot, and satisfactorily address, potentially leading to line delays, unexpected expenses, and in extreme cases catastrophic losses due to cascading events.
A mesh network may be used for local and in some cases external communications in an area. A mesh network (or simply meshnet) may comprise a local area network topology in which the infrastructure nodes (i.e., bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients. A wireless network may comprise an infrastructure made up of devices that are wirelessly coupled to each other. The devices may help forwarding packets for one another so that the network can cover a larger area without the user needing to set up a dedicated infrastructure or wired connection for each device. The lack of dependency on one node, and decentralized decision-making and node cooperation may allow for every node to potentially participate in the relay of information. Mesh networks may dynamically self-organize and self-configure, which can reduce installation overhead. The ability to self-configure enables dynamic distribution of workloads, particularly in the event a few nodes should fail. This in turn contributes to fault-tolerance and reduced maintenance costs. Mesh topology may be contrasted with conventional star/tree local network topologies in which bridges/switches are directly linked to only a small subset of other bridges/switches, and the links between these infrastructure neighbours are hierarchical. While star-and-tree topologies are very well established, highly standardized and vendor-neutral, vendors of mesh network devices have not yet all agreed on common standards, and interoperability between devices from different vendors is not yet assured.
Mesh networks may relay messages using either a flooding technique or a routing technique which makes them different from non-mesh networks. With routing, the message may be propagated along a path by hopping from node to node until it reaches its destination. To ensure that all its paths are available, the network may allow for continuous connections and must reconfigure itself around broken paths, using self-healing algorithms such as Shortest Path Bridging and TRILL (Transparent Interconnection of Lots of Links). Self-healing allows a routing-based network to operate when a node breaks down or when a connection becomes unreliable. As a result, the network may be quite reliable, as there is often more than one path between a source and a destination in the network. Although mostly used in wireless situations, this concept can also apply to wired networks and to software interaction.
Mesh networks may have a variety of features and parts. A mesh network whose nodes are all connected to each other is a fully connected network. Fully connected wired networks have the advantages of security and reliability—problems in a cable affect only the two nodes attached to it. However, in such networks, the number of cables, and therefore the cost, goes up rapidly as the number of nodes increases. By contrast, in a partially connected network, nodes may be connected to neighbouring or adjacent nodes, creating a subnet, but without direction connections with all other nodes in the network. Mesh networks may contain one or more of gateways or border routers, mesh devices or routers, and leaf devices. A border router, sometimes interchangeably referred to as a gateway router, may be the interface to the outside world, and may connect the wireless mesh network to a building Ethernet, or connecting to a cloud service via Internet, for instance via LTE (Long Term Evolution) or 3G. A mesh device may be a device that helps build up the actual mesh, and may act to forward, or route, data to and from other nodes hence being the mesh backbone. Leaf devices may be devices that are part of the mesh network, but do not help creating the infrastructure. Such may not forward traffic on behalf of others, but may communicate via the network. Leaf devices are often devices that needs to conserve energy due to constraints on battery. In a wired mesh, shortest path bridging and TRILL, may each allow Ethernet switches to be connected in a mesh topology, and allow for all paths to be active. IP (Internet Protocol) routing may support multiple paths from source to destination.
A wireless mesh network (WMN) may be a network made up of radio nodes organized in a mesh topology. Such may also be a form of wireless ad hoc network. In telecommunications networks, a node (Latin: nodus, ‘knot’) may be either a redistribution point or a communication endpoint. The definition of a node depends on the network and protocol layer referred to. A physical network node may be an electronic device that is attached to a network, and is capable of creating, receiving, or transmitting information over a communication channel. A passive distribution point such as a distribution frame or patch panel may consequently not be a node. Radio communication may be the technology of signaling and communicating using radio waves. Radio waves include electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). Such may be generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. A wireless mesh may be self-healing if it can automatically repair itself when the environment changes. It could for instance be that a link between two nodes that worked perfectly fine an hour ago is now blocked by a bookshelf, a truck, or a steel door. The network will then automatically, without the involvement of any user, change its topology to be able to route the traffic a different path.
Mesh networks may have various advantages and disadvantages. In a full mesh or fully connected mesh network, the nodes within the network may be connected with every other. For example, if there are n number of nodes during a network, each node will have an n−1 number of connections. A full mesh provides an excellent deal of redundancy, but because it is prohibitively expensive to implement, it's usually reserved for network backbones. The partial mesh may be more practical as compared to the full mesh. In a partially connected mesh, all the nodes aren't necessary to be connected with one another during a network. Peripheral networks are connected using partial mesh and work with a full-mesh backbone in tandem. Advantages of Mesh Topology may include one or more of a) failure during a single device won't break the network, b) there may be no traffic problem as there is a dedicated point to point links for every computer, c) fault identification is straightforward, d) the topology provides multiple paths to succeed in the destination and tons of redundancy, e) such provides high privacy and security, f) data transmission is more consistent because failure doesn't disrupt its processes, g) adding new devices won't disrupt data transmissions, h) the topology has robust features to beat any situation, and i) a mesh doesn't have a centralized authority. Disadvantages of Mesh Topology include one or more of: a) may be costly as compared to the opposite network topologies i.e. star, bus, point to point topology, b) installation is extremely difficult in the mesh, c) power requirement is higher as all the nodes will need to remain active all the time and share the load, d), complex processes are needed, and complex algorithms, e) the cost to implement mesh is above other selections, f) there is a high risk of redundant connections, g) each node requires a further utility cost to think about, and h) maintenance needs are challenging with a mesh.
Embodiments of this disclosure may include protocols that aim to create a reliable, reactive, and power efficient system for a low power wireless communication network in remote area where infrastructure for constant power and hi-speed internet is not available. Such protocols may aim to solve the challenges of wireless communication over a long linear infrastructure such as rail tracks, mining conveyor, pipe line where power options are limited, and where mainstream communication modes, such as cellular network, satellite network are spotty, expensive, or non-existent. In some cases, the systems disclosed herein may be used on any communication applications, whether residential, industrial, remote, urban or other variety. Such protocols may dynamically allocate higher energy communications to adapt to the local limitations created by the variation of natural sources of power such as solar and wind over long distance, linear infrastructure and selects the most power smart communication mode in real time. Such protocols may be used as an application layer for any low power wireless mesh network. A core component of some of these protocols is the dynamic assignment of a border router role based on the availability of energy, wireless wide-area network (WWAN) link quality, low power wireless mesh network link quality and microcontroller unit (MCU) utilization of the node for any smart nodes on the network.
A communications system, according to the present disclosure, may provide a cost-effective overlay system for remote communications and data transfer. The system may be used to transfer data from a locomotive or other railway or trackside equipment to data processing centres for analytics. The system may also be used for point-to-train communications in remote areas where other forms of wireless communications, such as cellular networks, are unavailable.
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Each node 12 may have a processor, a power source, and a wireless transceiver, which are mounted within a housing. Preferably, the power source is a battery charge by a solar cell mounted on or near the node 12. Other power sources may be used, where available, such as a wired power supply, a wind power generator, or other form of available harvested energy. The processor 118 may control the electrical components of the node 12 and may be mounted inside the housing 48. Preferably, the processor is a microcontroller unit (MCU) or central processing unit (CPU) installed on a printed circuit board (PCB) with the other electronic components of the node 12. The nodes 12 may also have a display 56 mounted within the housing 48. Preferably, the display 56 is a touch display, such as an OLED (Organic Light-emitting Diode) touch panel, to facilitate easy user interface for diagnostics, maintenance, or other such tasks. Other electrical components which may be mounted within the housing 48 of each node 12 include: memory, storage, and peripheral connections, such as USB or serial ports, or other types of data ports.
The wireless transceiver may use any suitable type of wireless communication, such as satellite communication, broadcast radio, microwave communication, cellular network, infrared communication, Bluetooth, Wi-Fi, mesh network, or other suitable type of wireless communication. Preferably, each node 12 may be capable of communicating with a cellular network for long distance communication (i.e., with the long-range network 18), via an IEEE™ (Institute of Electrical and Electronics Engineers) transceiver, and with a mesh network for short distance communication with adjacent nodes 12, via a low-frequency radio transceiver.
The use of a low-frequency radio transceiver for node-to-node communications provides a longer range for node-to-node communications and lower power consumption compared to many other types of wireless communication. Using this type of wireless transceiver to communicate node-to-node within the mesh network also permits fewer nodes to be used to cover long stretches of railway lines in remote regions where there are gaps in cellular coverage. The long-range of such a wireless transceiver also permits nodes 12 to communicate with non-adjacent nodes 12 and, thereby, provides some redundancy to the mesh network, in the event of a failure or communication error with one node 12. In the event of such a failure, the signal could “skip” the affected node 12 and thereby maintain communication between the other nodes 12 and the long-range network 18.
The gateway routers 26 are optional and, preferably, each node 12 has multiple wireless transceivers or a single wireless transceiver capable of multiple types of wireless communication to enable the nodes 12 to also perform the function of the gateway routers 26. Where gateway routers 26 are used, they are preferably installed on or with existing track-side communication equipment to facilitate communication over existing communication infrastructure. For example, a gateway router 26 could be installed where existing track-side equipment is already connected to a local power grid and wired (or wireless) communication network, to facilitate communication between nearby nodes 12 and the available connection to a long-range network 18, such as a fibre-optic network or cellular network.
Where gateway routers 26 are not used, each node 12 may be able to communicate via both short and long-distance wireless communication. Alternatively, only selected nodes 12, which are installed within range of a long-range network 18, may be configured for both short and long-distance wireless communication, to reduce the cost of nodes 12 located in gaps in cellular coverage. As a result, nodes 12 can operate both as a “local” node, communicating via the mesh network, and an “uplink” node, communicating via the long-range network 18. Nodes 12 may be assigned as either local nodes or uplink nodes (border routers) by the remote data processing centre system 30 or automatically. Local nodes may leave their long-distance wireless transceiver, such as a cellular modem, powered off to save power.
Preferably, uplink nodes are assigned automatically and dynamically by software running on each node 12 communicating over the mesh network. The software analyzes each node's 12 performance, based on a number of performance factors, to identify the best candidates for uplink nodes. The performance factors may include: battery performance, number of other nodes in communication range, cellular signal strength, number of other nearby candidate uplink nodes, distance to the nearest suitable candidate uplink node, or other relevant factors. For example, a node with consistently stronger cellular signal strength than other nodes would be a better candidate for an uplink node. Similarly, a node in range of more than one other node would be a better candidate, as would a node with consistently better battery performance (due to better positioning of its solar panel, etc.). The various performance factors may be weighted to produce an overall value that permits identification of the best candidate nodes.
The system may also periodically re-evaluate candidate nodes 12, and re-assign nodes 12 as local nodes or uplink nodes, when appropriate. For example, due to the additional power required for communication with the long-range network 18, an uplink node may drain its battery below a certain threshold, triggering another nearby local node to be re-assigned as an uplink node, at least until the former node can recharge its battery and resume service as an uplink node. In this way the system is able to dynamically assign uplink nodes to maintain optimal power consumption and a desired number of uplink nodes for optimal communications.
In operation, the system is installed track-side along a railway line to facilitate communication with a locomotive or other railway or track-side equipment. In one exemplary embodiment, the system may be used to facilitate communications for a train protection system, such as a positive train control (PTC) system. In such a system, information on track conditions ahead of a locomotive is sent to a control unit on the locomotive, which adjusts the speed of the train accordingly. Interruptions of communication with the locomotive's control system, such as occurs in remote areas with gaps in cellular coverage can compromise safety or train operations. For example, if track conditions ahead of a locomotive change after it enters a region of railway line in an area with a gap in cellular coverage, it may be too late for the control unit to safely slow the train by the time the locomotive exits the area and re-establishes communication. The communications system of the present disclosure provides an alternative method of communicating with the control unit on the locomotive in such remote areas to enable uninterrupted communication of information on track conditions.
If information on track conditions changes, such as in the event an emergency condition is detected, while the locomotive is out of communication contact with a long-range network the emergency condition would be transmitted to the nearest gateway router or uplink node, via the long-range network. The emergency condition would then be transmitted node-to-node, via the mesh network, until it reaches a node within communication range of the locomotive. The emergency condition is then transmitted, via the same type of wireless communication used between nodes, preferably a low-frequency radio transceiver, to the control system on the locomotive. The control system may then take appropriate action, such as applying the brakes, in response to the emergency condition, while the train is still within the region of railway line located in a gap in cellular coverage, before the locomotive is able to re-establish a direct connection with the long-range network. This provides vital additional time for the control system on the locomotive to respond to the emergency condition, thereby improving train safety and reducing the risk of derailments, collisions, or other serious incidents.
In addition to being used to facilitate communications with a long-range network in remote regions, the system may also be used to broadcast information locally within the mesh network. For example, if the system is connected with track-side sensors or other safety equipment to transmit that information to a data processing centre, the nodes or gateway routers may also have software to analyze the data from track-side sensors to determine if the data indicates an emergency condition. The system may then broadcast the emergency condition for a set number of node-to-node relays, from the node(s) detecting the condition, which may vary depending on the nature of the emergency condition. For example, a condition requiring a train to slow before passing through a certain section of track may be broadcast through the mesh network for a distance equal to the distance required for a train to slow from its normal travelling speed on that section of track to the reduced speed required by the track condition. This local signal may be broadcast, regardless of whether the signal is being transmitted to the data processing centre, via a gateway router or uplink node. This permits the control system on a locomotive to receive the information on the emergency condition even in the event of a communication failure between the system and the data processing centre.
The present disclosure has been described and illustrated with reference to an exemplary embodiment, however, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as set out herein. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed herein.
In the claims, the word “comprising” is use in its inclusive sense and does not exclude other elements being present. The indefinite articles “a” and “an” before a claim feature do not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2022/050798 | 5/19/2022 | WO |
Number | Date | Country | |
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63190511 | May 2021 | US |