A method for route discovery in a multi-PHY wireless network

Abstract

: A method (600) for discovering a route to a destination node in a wireless network (100), which comprises a plurality of nodes (300, 300') operated according to a first communication protocol associated with a first physical layer, PHY, and two or more nodes (300') also support a second PHY, the method (600) comprising steps of: modifying (S601), by a first node out of the two or more nodes (300'), a route request, formatted according to a 5 routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; broadcasting (S602), by the first node, the modified route request via the first PHY; receiving (S603) the modified route request by a second node out of the two or more nodes (300'); recording (S604), by the second node, the capability of the first node for the second PHY; updating 10 (S605), by the second node, the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node and rebroadcasting the modified route request after updating it.

Description

[0001] 2024PF80186

[0002] 1

[0003] A method for route discovery in a multi-PHY wireless network

[0004] FIELD OF THE INVENTION

[0005] The invention relates to the field of wireless communication. More particularly, various methods, apparatus, and systems are disclosed herein related to route discovery in a multi-PHY wireless network.

[0006] BACKGROUND OF THE INVENTION

[0007] Wireless mesh networks are becoming increasingly popular in the context of the Internet of Things (loT), where they are often used to facilitate communication between devices. For example, wireless mesh networks may be used for lighting control, home and building automation. In this scenario, a wireless mesh network can be used to connect a variety of smart devices, such as light bulbs, thermostats, home appliances, and security cameras.

[0008] By using a wireless mesh network, these devices can communicate with each other directly, without the need for a central hub or controller. This can result in a more reliable and efficient system, as devices can communicate even if some nodes in the network are offline or malfunctioning. Additionally, the use of wireless mesh networks can reduce the overall cost and complexity of home automation systems, as it eliminates the need for complex wiring and infrastructure.

[0009] Routing is an essential component of wireless mesh networks because it determines how data is transmitted between different nodes in the network. Unlike traditional wireless networks where devices communicate directly with a central access point, wireless mesh networks rely on a distributed network of interconnected nodes to relay data to its destination. Each node in the network may act as a router, forwarding data packets to other nodes until they reach their intended destination.

[0010] Sometimes, due to the dynamic nature of the network, as nodes may join or leave the network at any time, routing protocols need to be able to adapt to changes in the network topology in real-time. Additionally, the limited resources of individual nodes in the network, such as processing power and battery life, shall also be taken into account when designing a routing protocol. 2024PF80186

[0011] 2

[0012] US20180176119A1 relates to a method and apparatus for routing multiple data streams simultaneously through independent routes between multiple-input-multiple- output (MIMO) stations in a mesh network.

[0013] SUMMARY OF THE INVENTION

[0014] For wireless networks, as the requirements for data rates, energy efficiency, and support for new applications and services become higher and higher, it has become a trend to enable a second physical layer (PHY) in addition to the default PHY supported by the system. For example, one or more high-performance PHYs may be deployed additionally in some of the nodes in the network to meet new requirements.

[0015] However, the support of hybrid PHYs also brings new challenges to the network design. As discussed above, route discovery is very important for decentralized wireless networks in order to achieve efficient data transmission. At the same time, routing can also be resource-intensive, especially as the network scales up. For the efficiency purpose, it is not desirable to replicate all the protocol stacks for the second PHY, and then the compatibility among the nodes needs to be considered. Therefore, it is important to provide a route discovery mechanism that can efficiently handle multi-PHY scenarios.

[0016] It is recognized by the inventors that it is beneficial to employ a single route discovery procedure to search for a route to a destination node via hops according to the first PHY, the second PHY, or a combination of both PHYs. More particularly, the goal of this invention is achieved by a method as claimed in claim 1, and by a wireless communication system as claimed in claim 10.

[0017] In accordance with a first aspect of the invention a method is provided. A method for discovering a route to a destination node in a wireless network, wherein the wireless network comprises a plurality of nodes operated according to a first communication protocol associated with a first physical layer, PHY, and two or more nodes out of the plurality of nodes also support a second PHY, the method comprising steps of: modifying, by a first node out of the two or more nodes supporting the second PHY, a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; broadcasting, by the first node, the modified route request via the first PHY ; receiving the modified route request by a second node out of the two or more nodes supporting the second PHY; 2024PF80186

[0018] 3 recording, by the second node, the capability of the first node for the second PHY; updating, by the second node, the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node and rebroadcasting the modified route request after updating it; measuring, by the second node, a received signal strength of the modified route request received from the first node; determining if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

[0019] Since the first PHY is supported by all the nodes in the wireless network, it is beneficial to make use of the first PHY to broadcast the route request, without introducing compatibility problems. And the route discovery procedure in such a multi-PHY scenario is built on top of a routing protocol compliant to the first communication protocol.

[0020] A first node supporting the second PHY makes modification to a route request by adding an indication of its capability for the second PHY and its address associated with the capability, which enables a second node that is also second PHY capable to record such information related to the second PHY. As the modified route request propagates, all nodes with second PHY capability can build their local routing table with additional information about the second PHY compatibility of each neighboring node or build a separate routing table for the second PHY.

[0021] In a preferred embodiment, the method further comprises a step of: recording, by the second node, the capability of the first node for the second PHY only after determining that the first node is the transmitter from which it receives the modified route request.

[0022] For the second node to make the bookkeeping on the second PHY capability, it is beneficial to compare the address associated with the capability for the second PHY and the address of the node from which it receives the route request, such that the second node can identify if its direct neighbour support second PHY or not.

[0023] In one example, the method may further comprise a step of determining, by the second node, whether the address associated with the capability for the second PHY indicated in the modified route request is the same as the address of a transmitter from which it receives the modified route request. 2024PF80186

[0024] 4

[0025] Advantageously, the method further comprises a step of: sending, by a third node knowing a route to the destination node, a route reply formatted according to the routing protocol in response to a node from which the route request, the modified route request, or another updated version of the modified route request is received.

[0026] In one example, the method further comprises a step of: modifying, by the first node, the second node, or the third node if supporting the second PHY, the route reply by adding an indication of its capability for the second PHY and its address associated with the capability.

[0027] For nodes that have the second PHY enabled, it is beneficial to update the address information in the route reply to declare their support for the second PHY when passing through the route reply message.

[0028] Preferably, the method further comprises: receiving, by a further node out of the two or more nodes supporting the second PHY, the modified route reply; recording, by the further node, the capability for the second PHY of a node from which the modified route reply is received from.

[0029] For the further node to make the bookkeeping, it is beneficial to compare the address associated with the capability for the second PHY and the address of the node from which it receives the route reply, such that the further node can identify if the direct neighbour on the route support second PHY or not.

[0030] In one example, the method further comprises: measuring, by the second node, a received signal strength of the modified route request received from the first node; determining if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

[0031] Since the route request is transmitted via the first PHY, in order to evaluate the connectivity via the second PHY between the two nodes it is necessary to take the link budget offset into account. The link budget offset between two different physical layers refers to the difference in power levels required to achieve the same signal quality or bit error rate (BER) performance. This offset is due to differences in the modulation schemes, coding rates, and other parameters used by the different physical layers. Generally, a higher data rate 2024PF80186

[0032] 5 physical layer will require a higher transmit power to achieve the same signal quality as a lower data rate physical layer.

[0033] Advantageously, the method further comprises: preferably selecting by the first node a forwarding node that is the second PHY capable when there are more than one candidate nodes available for the next hop.

[0034] With a forwarding node that is the second PHY capable, it is possible to send a data packet with a higher data rate. By sending a packet with a higher data rate, it saves energy for both transmission node and receiving node, because less time is required for transmission and reception. This also helps to reduce the chance of packet collision in a network, since the airtime is shorter. Thus, it is beneficial to preferentially select the second PHY for both energy efficiency purposes and performance purposes.

[0035] In one example, the routing protocol is one of Ad hoc On-Demand Distance Vector, AODV, routing protocol, Dynamic Source Routing, DSR, protocol, Destination- Sequenced Distance-Vector, DSDV, routing protocol, Optimized Link State Routing, OLSR, protocol, Routing Protocol for Low-Power and Lossy Networks, RPL.

[0036] In another example, when modifying the route request by the first node, an additional field on a hop count related to the second PHY is added to the route request.

[0037] A hop count is the number of nodes that a packet must traverse to reach its destination. By recording the hop count, a routing protocol can determine the path with the least number of hops, which is typically the shortest path. This can be an important aspect when selecting a route, especially for time critical applications.

[0038] By recording the number of hops for the second PHY separately, it allows the routing protocol to select a route by considering both the data rate to be supported and the number of relays involved

[0039] In accordance with a second aspect of the invention a wireless network is provided. A wireless network comprising a plurality of nodes configured to operate according to a first communication protocol associated with a first physical layer, PHY; wherein two or more nodes out of the plurality of nodes also support a second PHY ; the wireless network comprising: a first node, out of the two or more nodes supporting the second PHY, configured to: modify a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; and broadcast the modified route request 2024PF80186

[0040] 6 via the first PHY; wherein the route request is used to discover a route to a destination node in a wireless network; a second node, out of the two or more nodes supporting the second PHY, configured to: receive the modified route request; recording the capability of the first node for the second PHY; update the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node; and rebroadcast the modified route request after updating it; measure a received signal strength of the modified route request received from the first node; and determine if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

[0041] Advantageously, the second node is further configured to record the capability of the first node for the second PHY only after determining that the first node is the transmitter from which it receives the modified route request.

[0042] Preferably, the first communication protocol is according to a Zigbee protocol, a Thread protocol, or a BLE mesh protocol.

[0043] In one option, the modification made to the route request is implemented via adding a Manufacturer Specific Global Type-Length-Value, TLV, data element.

[0044] A Manufacturer Specific Global Type-Length-Value (TLV) data element is a type of TLV data element that is used to carry proprietary data in a network protocol. It is typically used by manufacturers to add custom information to standard data structures. The Manufacturer Specific TLV typically comprises a three-byte header that includes a manufacturer ID and a type code, followed by a variable-length value field. The manufacturer ID is a unique identifier that identifies the manufacturer of the TLV, and the type code is used to identify the specific type of data carried in the TLV. The value field contains the actual data, and its length is determined by the length field in the TLV header.

[0045] Given the flexibility of using a TLV data element, it is considered to be a convenient approach to modify the route request via adding a TLV data element.

[0046] Beneficially, the second PHY supports a higher data rate than the first PHY.

[0047] In a wireless network, a higher data rate can reduce the end-to-end latency for routing messages among the nodes, which can improve the response time of the network. This is particularly important in time-critical applications where a delay in data transmission may result in a loss of data or even system failure. A higher data rate may also improve the 2024PF80186

[0048] 7 energy efficiency of the network since it helps the nodes to reduce the time used to transmit and / or receive data. This can help to conserve energy for battery-powered nodes and extend the lifetime of the network. Furthermore, the second PHY supporting a higher data rate can also increase the capacity of the network by allowing more data to be transmitted in a given time period, such that network congestion may be reduced.

[0049] Overall, enabling a higher data rate by the second PHY may provide significant benefits in terms of network performance, energy efficiency, and the ability to support new applications and services in a wireless network.

[0050] In one example, the wireless network comprises at least one node out of the plurality of nodes integrated in or connected to a lighting device.

[0051] Lighting systems are becoming more and more wirelessly connected for both professional and home use cases. Devices in these wireless connected systems communicate using either standardized or proprietary protocols.

[0052] Zigbee standard is widely adopted in home automation and lighting control applications. The Zigbee network layer natively supports both star and tree networks, and generic mesh networking. The powerful topology control provides it great flexibility in a control system, especially for reaching destination nodes that are far away from a source node with direct link.

[0053] A control command may be initiated by a central controller of the system, such as a proxy node, a gateway, or a central switch. The control command may be delivered via one or more nodes out of the plurality of nodes for the control of the lighting device.

[0054] BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In the drawings, like reference characters generally refer to the same parts throughout the different figures. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0056] Fig. 1 illustrates a wireless network comprising a plurality of nodes;

[0057] Fig. 2 illustrates one example of a network comprising 5 nodes; and Fig. 3 shows a flow diagram of a method for discovering a route to a destination node in a wireless network.

[0058] DETAILED DESCRIPTION OF EMBODIMENTS

[0059] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments. Upon reading the following description in light of the 2024PF80186

[0060] 8 accompanying drawings, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0061] FIG. 1 illustrates a wireless network 100 comprising a plurality of nodes 300, 300’. The plurality of nodes 300, 300’ are configured to operate according to a first communication protocol associated with a first physical layer (PHY); wherein two or more nodes 300’ out of the plurality of nodes 300, 300’ also support a second PHY.

[0062] The wireless network 100 comprises a first node, out of the two or more nodes 300’ supporting the second PHY, configured to: modify a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; and broadcast the modified route request via the first PHY; wherein the route request is used to discover a route to a destination node in a wireless network 100; and a second node, out of the two or more nodes 300’ supporting the second PHY, configured to: receive the modified route request; recording the capability of the first node for the second PHY ; update the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node; and rebroadcast the modified route request after updating it. The second node may be further configured to record the capability of the first node for the second PHY only after determining that the first node is the transmitter from which it receives the modified route request.

[0063] The first communication protocol may be according to a Zigbee standard, a Thread standard, or a BLE mesh standard. The first PHY may be the corresponding PHY of a Zigbee standard, a Thread standard, or a BLE mesh standard.

[0064] The second PHY is different from the first PHY. Beneficially, the second PHY supports a high data rate than the first PHY. The second PHY may be according to a proprietary mode.

[0065] For example, the second PHY may be a High-speed PHY, which is more performing with respect to bit rate and / or bandwidth, but at the cost of a more limited communication range. To support a higher bit rate, a larger link budget is typically required.

[0066] Routing or route discovery is the process of determining the most efficient path for transmitting data from a source node to one or more destination nodes in a network. In a wireless mesh network, routing is especially important because of the decentralized 2024PF80186

[0067] 9 nature of the network. Without proper routing, the wireless network may become congested, leading to slow data transfer and increased latency. In the meanwhile, routing in a wireless network can be quite resource intensive, especially with the scaling of the network. A route request is typically sent via broadcasting, which triggers many nodes in the network to communicate with its neighbours to determine the best path for data to travel. This type of communication can impose a significant overhead on network resources. Therefore, it is crucial to implement efficient routing algorithms and strategies to ensure the optimal performance of a wireless network.

[0068] The wireless network 100 addressed by the present invention comprises more than one PHY in a hybrid network setting. With certain nodes capable to support the second PHY, it is also desirable to take advantage of those nodes, such as supporting higher data rate and reducing end to end latency via the second PHY. Given the overhead of routing algorithms on the network load, the goal of the present invention is to make use of a single routing procedure to establish a route towards a destination node either via a first PHY, via a second PHY, or via a combination of both PHYs.

[0069] Since the first PHY is supported by all the nodes 300, 300’ in the wireless network 100, it is thus proposed to build up the routing procedure via the first PHY and based on a routing protocol known to the first communication protocol. And then the support to the second PHY by the two or more nodes 300’ is recorded or registered via modified routing messages.

[0070] The routing protocol may be one of Ad hoc On-Demand Distance Vector (AODV) routing protocol, Dynamic Source Routing (DSR) protocol, Destination-Sequenced Distance-Vector (DSDV) routing protocol, Optimized Link State Routing (OLSR) protocol. The selection of the routing protocol may be carried out based on the size of the wireless network 100, the mobility of the plurality of nodes 300, 300’ in the network, or the traffic load of the network.

[0071] In the following, we will take a Zigbee network with a subset of nodes supporting a second PHY and the AODV routing protocol as an example for the ease of explanation.

[0072] The route discovery procedure in such a hybrid Zigbee network may be built on top of the route discovery protocol of a conventional Zigbee network with the modification on the Route Request / response format and the selection criteria. Note that a Route Request is broadcast over the conventional Zigbee network. 2024PF80186

[0073] 10

[0074] It’s proposed to extend Zigbee’s Route Request command with a custom Zigbee Type-Length-Value (TLV) data element to signal anode’s High-speed PHY support. Nodes that receive this extended Route Request command can use this TLV to mark in their bookkeeping that the transmitter of the command is High-speed PHY capable. The Route Request command establishes the reverse route from the request’s destination to its originator, by creating / updating applicable routing table entries along the way.

[0075] The Route Reply command is sent via unicast to the originator of an incoming AODV Route Request command using the reverse route established earlier. The Route Reply command establishes the forward route from the initiator of the AODV Route Request to its destination, by creating / updating applicable routing table entries along the way. In case a node is High-speed PHY capable, then it extends the Route Reply command with the custom TLV to signal High-speed PHY support. Nodes that receive the Route Reply command can use this TLV to mark in their bookkeeping that the transmitter of the command is High-speed PHY capable.

[0076] Nodes use their High-speed PHY bookkeeping to determine if the next hop of an outgoing unicast message supports the faster High-speed PHY. The outgoing unicast message is sent to the next hop via the High-speed PHY in case that node is within Highspeed PHY proximity / range. To determine if a hop is within High-speed PHY proximity / range, the sending node applies an estimated link cost offset for the High-speed PHY compared to the hop’s (outgoing) cost as established for the standard 802.15.4 PHY, which also works for asymmetric links. Optionally, it is also possible to collect additional link cost information of High-speed PHY links, based on regular messages or dedicated High-speed PHY link status messages.

[0077] Using the mechanism as described above, the Route Reply commands may also be sent using the High-speed PHY. In case an incoming Route Reply command was sent via the High-speed PHY, then it means that the sending node supports the High-speed PHY. This may be used as an alternative (and preferred) mechanism to signal a node’s High-speed PHY support and thus omit the custom TLV from the Route Reply command.

[0078] In case of source routing, the Route Record command is a unicast message that may be sent before a regular unicast message is sent to a collector node. The Route Record command establishes the forward route from collector node to the command’s originator as the command traverses through the network to the collector node. The upcoming Zigbee R23 specification does not allow the addition of TLVs to the Route Record command, so the custom TLV cannot be added with this command to signal High-speed 2024PF80186

[0079] 11

[0080] PHY support. However, like the AODV Route Reply, the High-speed PHY support can be derived by checking if the Route Record command was sent via the High-speed PHY.

[0081] In summary, for the route-discovery phase it is proposed to extend Zigbee's Route Request command with a custom TLV that signals a node’s High-speed PHY support, and store this as additional routing information. The route reply may be sent via the first PHY to reverse the path established via the route request and by adding a TLV to the message when necessary. Optionally, the reply may already be sent by using the High-speed PHY where possible to avoid having to add a TLV to the reply. If a message is received via the High-speed PHY the additional routing information is also updated accordingly. Additionally, for sending messages (after the route discovery) it is proposed to use the additional routing information combined with link cost information related to the High-speed PHY to determine if a message can be sent using the High-speed PHY or not. The link cost can be obtained by computing an offset of the regular link cost, or by collecting information of messages sent via the High-speed PHY.

[0082] It can be seen that the proposed solution can work with any number of Highspeed PHY capable nodes, ranging from 2 nodes to the entire network. The solution provides a mechanism that enables High-speed PHY capable nodes to determine which of their neighbouring nodes also support the High-speed PHY and indicates how to determine if those nodes are within High-speed PHY range.

[0083] For illustration purpose, FIG. 2 provides an example with a small wireless network comprising 5 nodes. In this example, it’s assumed that node A is a concentrator node that broadcasts a many-to-one Route Request (MTORR). A many-to-one route request for routing is a type of communication protocol used in wireless sensor networks (WSNs) for data transmission. According to this protocol, multiple sensor nodes in a network send route requests to a single destination node, which then selects the best path for data transmission. This technique is useful in situations where multiple source nodes are trying to transmit data to a single base station or sink node, as it allows for efficient routing of data and reduces the overall energy consumption of the network.

[0084] It’s further assumed in this example that all nodes in the network can support the standard IEEE 802.15.4 PHY, and the second PHY is a proprietary High-speed PHY supported by most of the nodes in the network except for legacy node C. Note that the disclosed routing mechanism is not limited to the first and second PHYs used in this example, which also works with other combinations of two different PHYs. 2024PF80186

[0085] 12

[0086] Signalling of anode’s High-speed PHY support in the Route Request command can be done via a Manufacturer Specific Global Type Length Value (TLV) (see Zigbee R23, annex I). Only nodes that support the second PHY (or high-speed PHY in this example) are aware of this TLV. Nodes that support the High-speed PHY will add the TLV when sending / relaying the Route Request. Nodes that do not support the second PHY are not aware of the (custom) TLV and may either drop it or include it as-is in the forwarded Route Request. Forwarding of the Route Request - including the TLV as-is - may result in a receiving node concluding that the sender does support the High-speed PHY. To prevent this the High-speed PHY capable node adds its short address to the Manufacturer Specific Global TLV, which can be used by a receiving node to validate if it was really the direct transmitter of the incoming Route Request that supports the High-speed PHY.

[0087] Following the Zigbee specification, a node that receives an incoming Route Request may lead to creation / updating of a routing table entry for the source of the route request. Standard Zigbee behaviour on route selection is based on path cost. To maximize the use of the High-speed PHY, the route selection is changed such that the node favours Highspeed PHY capable nodes as a next hop, if the High-speed PHY link quality between that node and the next hop is deemed to be sufficient. The bookkeeping on which nodes support the High-speed PHY can be added as a custom extension to the existing routing table, or it may be implemented as a new custom table.

[0088] When a High-speed PHY capable node wants to send / forward a unicast message to the next hop, then it first checks if the next hop supports the High-speed PHY (via the new bookkeeping). If this is the case, then the node will send out the unicast message via the High-speed PHY. If this is not the case, then the standard 802.15.4 PHY is used to send the unicast message.

[0089] The Route Record command (as used for source routing) is sent via unicast and makes use of this mechanism that is described above. Thus, where possible, these commands traverse the network using the High-speed PHY. As such, the relay list that is build up when the Route Record command traverses the network runs via High-speed PHY capable nodes. This ensures that the forward route as copied by the concentrator from this relay list is also optimized to run as much as possible via High-speed PHY capable nodes.

[0090] The Route Reply command (as used in AODV) is also sent via unicast and thus makes use of the same mechanism described above. Upon receipt of a Route Reply command via the High-speed PHY and in case the receiving device is not the destination, then the device shall indicate in its High-speed PHY bookkeeping that the forwarder of the 2024PF80186

[0091] 13 route reply command supports the High-speed PHY. This mechanism ensures that the forward routes that are constructed due to this route reply are also optimized to run as much as possible via High-speed PHY capable nodes.

[0092] It’s also shown in FIG. 2 the build-up of routing tables throughout the network for nodes B, C, D, E. Each routing table comprises three columns representing the destination address, the next hop address, and if the next hop supports High-speed PHY. Specifically, note that nodes may prefer hops that are High-speed PHY capable over hops that only support the standard IEEE 802.15.4 PHY. Additionally, the custom TLV in the MTORR may include a field to store the number of High-speed PHY hops. The hop count is incremented every time the MTORR is sent over a High-speed PHY link. This High-speed hop count is stored in the bookkeeping table and used by the nodes to decide on which path to take for sending a message to the concentrator, node A. For example, node E has two options for the next hop to reach node A, via node C and via node D. Since node C is a legacy node that supports only the first PHY, node E may preferably choose node D as the next hop if higher data rate is needed. Similarly, node D also has two options for the next hop to reach node A, via node C and via node B. It can be seen that for high speed option, it is beneficial for node E to choose the route E-D-B-A, and for low latency, it is beneficial to choose the route E-C- A. The selection can be made based on the application requirements on latency, data rate, power consumption, etc.

[0093] FIG. 3 shows a flow diagram of a method 600 for discovering a route to a destination node in a wireless network 100. A method 600 for discovering a route to a destination node in a wireless network 100, wherein the wireless network 100 comprises a plurality of nodes 300, 300’ operated according to a first communication protocol associated with a first physical layer, PHY, and two or more nodes 300’ out of the plurality of nodes 300, 300’ also support a second PHY, the method 600 comprising steps of: modifying, in step S601, by a first node out of the two or more nodes 300’ supporting the second PHY, a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; broadcasting, in step S602, by the first node, the modified route request via the first PHY; receiving, in step S603 the modified route request by a second node out of the two or more nodes 300’ supporting the second PHY; 2024PF80186

[0094] 14 recording, in step S604, by the second node, the capability of the first node for the second PHY ; updating, in step S605, by the second node, the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node and rebroadcasting the modified route request after updating it.

[0095] The method may further comprise the following steps: recording, by the second node, the capability of the first node for the second PHY only after determining that the first node is the transmitter from which it receives the modified route request.

[0096] Optionally, the method may further comprise the following steps: measuring, by the second node, a received signal strength of the modified route request received from the first node; determining if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

[0097] The method according to the present invention may be implemented on a computer as a computer implemented method, or in dedicated hardware, or in a combination of both.

Claims

2024PF8018615CLAIMS:

1. A method (600) for discovering a route to a destination node in a wireless network (100), wherein the wireless network (100) comprises a plurality of nodes (300, 300’) operated according to a first communication protocol associated with a first physical layer, PHY, and two or more nodes (300’) out of the plurality of nodes (300, 300’) also support a second PHY, the method (600) comprising steps of: modifying (S601), by a first node out of the two or more nodes (300’) supporting the second PHY, a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; broadcasting (S602), by the first node, the modified route request via the first PHY; receiving (S603) the modified route request by a second node out of the two or more nodes (300’) supporting the second PHY; recording (S604), by the second node, the capability of the first node for the second PHY ; updating (S605), by the second node, the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node and rebroadcasting the modified route request after updating it; measuring, by the second node, a received signal strength of the modified route request received from the first node; determining if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

2. The method (600) of claim 1 further comprising a step of: recording, by the second node, the capability of the first node for the secondPHY only after determining that the first node is the transmitter from which it receives the modified route request.2024PF80186163. The method (600) of claim 1 or 2 further comprising a step of: sending, by a third node knowing a route to the destination node, a route reply formatted according to the routing protocol in response to a node from which the route request, the modified route request, or another updated version of the modified route request is received.

4. The method (600) of claim 3 further comprising a step of: modifying, by the first node, the second node, or the third node if supporting the second PHY, the route reply by adding an indication of its capability for the second PHY and its address associated with the capability.

5. The method (600) of claim 4 further comprising: receiving, by a further node out of the two or more nodes (300’) supporting the second PHY, the modified route reply; recording, by the further node, the capability for the second PHY of a node from which the modified route reply is received from.

6. The method (600) of any one of the previous claims further comprising a step of: selecting by the first node a forwarding node that is the second PHY capable when there are more than one candidate nodes available for the next hop.

7. The method (600) of any one of the previous claims, wherein the routing protocol is one of Ad hoc On-Demand Distance Vector, AODV, routing protocol, Dynamic Source Routing, DSR, protocol, Destination-Sequenced Distance-Vector, DSDV, routing protocol, Optimized Link State Routing, OLSR, protocol, Routing Protocol for Low-Power and Lossy Networks, RPL.

8. The method (600) of any one of the previous claims, wherein when modifying the route request by the first node, an additional field on a hop count related to the second PHY is added to the route request.2024PF80186179. A wireless network (100) comprising a plurality of nodes (300, 300’) configured to operate according to a first communication protocol associated with a first physical layer, PHY; wherein two or more nodes (300’) out of the plurality of nodes (300, 300’) also support a second PHY; the wireless network (100) comprising: a first node, out of the two or more nodes (300’) supporting the second PHY, configured to: modify a route request, formatted according to a routing protocol compliant to the first communication protocol, by adding an indication of its capability for the second PHY and its address associated with the capability; and broadcast the modified route request via the first PHY; wherein the route request is used to discover a route to a destination node in a wireless network (100); a second node, out of the two or more nodes (300’) supporting the second PHY, configured to: receive the modified route request; recording the capability of the first node for the second PHY; update the modified route request by replacing the address of the first node associated with the capability for the second PHY with its own address when the second node does not know a route to the destination node; and rebroadcast the modified route request after updating it; measure a received signal strength of the modified route request received from the first node; and determine if a communication link via the second PHY can be established between the first node and the second node based on a link budget offset between the first PHY and the second PHY.

10. The wireless network (100) of claim 9, wherein the second node is further configured to record the capability of the first node for the second PHY only after determining that the first node is the transmitter from which it receives the modified route request.

11. The wireless network (100) of claim 9 or 10, wherein the first communication protocol is according to a Zigbee protocol, a Thread protocol, or a BLE mesh protocol.

12. The wireless network (100) of claim 11, wherein the modification made to the route request is implemented via adding a Manufacturer Specific Global Type-Length-Value, TLV, data element.2024PF801861813. The wireless network (100) of claim any one of the previous claims 9-12, wherein the second PHY supports a higher data rate than the first PHY.

14. The wireless network (100) of any one of the previous claims 9-13 comprising at least one node out of the plurality of nodes (300, 300’) integrated in or connected to a lighting device.

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